4606 4610.output

* GB785013 (A)
Description: GB785013 (A) ? 1957-10-23
Acylated dl-proline salts and their use in obtaining d-and l-prolines
separately
Description of GB785013 (A)
Translate this text into Tooltip
[75][(1)__Select language]
Translate this text into
The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
PATENT SPECIFICATION
Date of Application and filing Complete Specification: March 8, 1955,
No 6828/55.
Application made in France on March 29, 1954.
Complete Specification Published: Oct 23, 1957.
Index at acceptance:-Class 2 ( 3), C 2 B( 10; 34), C 3 A 10 A( 4 G: 5
C: 5 F).
International Classification;-CO 7 c, do COMPLETE SPECIFICATION
Acylated DL-Proline Salts and their use in obtaining D and L-Prolines'
Separately We, U C L A F, formerly nmown as Usines Chimiques Des
Laboratoires Francais, of 89, Rue du Cherche-Midi, Paris VI , France,
a Body Corporate, organised according to the laws of France, do hereby
declare the invention, for which we pray that a patent may be granted
to us, and the method by which it is to be performed, to be
particularly described in and by the following statement:-
The present invention relates to a process for producing D and
L-proline by resolving derivatives of DL-proline, D and L-proline
havingthe general formula (I) The notation DL-prolline designates
racemic proline, a mixture in equal proportions of L-proline and its
enantiomorph, D-proline The present invention also relates to 1 the
salt of N-3,5-dinitrobenzoyl L proline with

D-()-threo-1-pnitrophenyl-2-aminoprop:ane-l,3-diol and the salt of
N-3,5-dinitrobenzoyl-D-proline with L ( +) threo, 1 -,p nitrophenyl 2
-amino propane-l,3-diol, said two salts, being new compounds The last
mentioned two, compounds are obtained from N
3,5-dinitrobenzoyl-DL-proline, II.
H f 1 Proline is one} of the glucose forming amino, acids which occur
in their levo rotatory form (L-proline), in the animal metabolism It
occurs otherwise in both its D and L form in the structure of various
polypeptides: in its D form the polypeptides of thie ergot of rye:
the L form occurs in', for example, gramicidin, ACTH and ocytocm.
As the methods of synthesizing proline lead to, the racemic comepound,
in order to obtain the isomers, it is necessary to have at lPrice 3 s
6 d 1 one's disposal a process for the resolution of racemie proline
which, is uncomplicated The only method for the resolution of
DL-proline which is actually known uses, as intermediate comnpound the
cinchonine salt of N-n-nitrobenzoylproline (of E FISCHER AND ZEMPLEN,
Ber dtsch chrnl Ges, 1909, 42, 2989).
According to the authors of thiis method the yield of the resolution
does not exceed 40 %.
Furthermore, when saponification of the Nm-nitrobenzoylated
derivatives of D and Lproline resulting thereby is effected, partial
racemisation is caused and this malwes it necessary to purify the D or
the L-proline by means of metallic salts as intermediate compounds.
In accordance with the present inventiont a process for the production
of D and L-proline comprises reacting L-(+) and D-(-)-threo1 p
-nitrophenyl-2-amnopropanel,3-diol as resolution agent with
N-3,5-dinitroblenzoylDL-proline in an inert solvent in which only one
of the two enantiomorphs givesi a salt with the resolution agent
sparingly soluble in the solvent, separating the salts of the two
enantiomorphs by means of the difference in their solubility,
liberating the N-3,5-dinitrobenzoyl-D and -L-proline from their
separated salts with the resolution agent by treatment with a base
followed by acidification, and saponifying the resulting D and
L-N3,5-dinitrobenzoylprolin Os separately to form D and L-proline
respectively Preferably the said inert solvent is an aliphatic
alcohol, e g.
ethyl alcohol.
The yield of the resolution effected by the p Tocess of the invention
as described in the examples given hereinafter is generally from to,
90 % The process according to the invention has the advantage of
leading to, the N-3,5 dinitrobenzoyl-D-proline and the
N-3,5dinitrobenzoyl 1 -proline which it is possible to hydrolyze
without significant racemisation taking place.
785,013 In patent application No 24,416/53 (Serial No 745,097) the

applicants have described the use of L-(
+)-threo-1-p-nitrophenyl-2aminopropan-1,3-diol as a means for the
resolution of DL-acyltryptophanes, for example the N-acetyl and
N-formyl-DL-tryptcphanes.
However, it has been found that, owing to the fact that they are too
soluble, the N-acetyland N-formyl-DL-prclines are not suitable for
resolving DL-proline On the other hand, it is possible to work with
N-3,5-dinitrobenzoylDL-proline (II): while the L-enantiomorphs of
acyltryptophanes form sparingly soluble salts with L (+)
threo-l-p-nitrophenyl-2aminoprepane-1,3-diel, the N 3,5 dinitrobenzoyl
D proline with L-(+)-threo-l-pnitrophenyl-2-aninopropane-1,3-diol
forms, a salt which is sparingly soluble in water or certain organic
solvents, e g ethyl alcohol, While the corresponding salt of
N-3,5-dinitrobenzoyl-L-proline remains entirely dissolved under these
conditions In accordance with the process of the invention it is
sufficient to isolate, e g by centrifuging or filtering the
precipitate resulting by the action of L-(+)threo-l-p-nitrophenyl 2
aminopropane-1,3diel on the racem ate of N-3,5-dinitrobenzoylproline
and to treat with a base, e g a caustic alkali in order to obtain the
alkali metal salt of N-3,5-dinitrobenzoyl-D-proline, which is
acidified teo give N 3,5 dinitrobenzoyl-Dproline, which is then
saponified to give Dproline By meanr, of a similar treatment of the
filtrate there is obtained N 3,5 dinitrobenzoyl-L-proline which,
however, may be contaminated by small quantities of the racemate In
general, a series of recrystallizaticns from an appropriate solvent is
sufficient in order to purify this roeduct When a more complete
purification is necessary, it is advantageous to treat the mixture by
means of D(-) thre-l-p-nitrcphenyl-2-amineprepanz1,3-diol which, in
contradistirnction to, its Le-nantiomorph, gives rise to a sparingly
soluble salt with N 3,5 dinitrobenzoyl-L-proline under the above
mentioned conditions This salt crystallizes and may be separated (e g.
by centrifuging or filtering while the corresponding salt formed with
N 3,5 dinitrobenzoyl D proline remains dissolved By treatment with a
caustic alkali followed by acidification and then saponifying it is
possible to obtain the pure L-proline quite easily.
For example, when one operates in an aqueous medium or in an organic
solvent such as ethyl alcohol, the
L-(+)-threo-l-p-nitrophenyl-2-aminopropane-1,3-diol gives riseto a
sparingly soluble salt of N-3,5-dinitrobenzoylD-proline, while the
salt of N-3,5-dinitrobenzoyl-L-proline remains dissolved The
N3,5-dinitrobenzoyl-D-preline obtained by the process of resolution in
accordance with the invention is used, as already indicated, in order
to obtain the D-proline The salt of N-3,5-dinitrobe-nzoyl-L-prclinc
which remains may be re-used in the resolution cycle either after

racemisation of the corresponding N-3,5dinitrobenzoyl-L-proline in
accordance with a known process (cf CARTER AND STEVANS, J.
Biol Chem 1940, 133, 127), or after racemisation of the L-proline
obtained by saponification of the N-dinitrobenzoylated derivative It
is known that optically active proline is easily racemised, for
example by heating to 140-145 ' C, in the presence of baryta water,
(compare Z Physiol Chem 1901, 33, 167).
By means of successive alternating resolutions and racemisations of
the L-form of proline, substantially the entire quantity of the Lform,
which occurs in nature, may b: converted to the D-form It is also
possible to operate in a similar manner in order to convert by means
of resolutions and racemisations effected successively substantially
the entire quantity of D-isomer occurring in nature into the L-form It
will be appreciated that there will always remain some L or D form in
the unconverted state since only half of the L or D form is converted
after each successive racem,-isation to the D or L form.
By liberating the N-3,5-dinitrbenzoyl-Dand L-prolines from their salts
by means of a caustic alkali, e g sodium hydroxide, more than 90 % of
the resolution reagent used for the process can be recovered The
recovered resolution reagent may be used again.
The N-3,5-dinitrobenzoyl-DL-proline may easily be prepared by
N-3,5-dinitrobenzoylation of DL-proline in accordance with the method
of SCHOTTEN-BAUMANN (cf SAUNDERS, J.Ghem Soc 1938, p 1397) It must be
noted that the said author' had not contemplated the use of this
derivative for the resolution of proline.
The L-( +)-threo-l-p-nitrophenyl-2-aminopropane-1,3-diol, a compound
obtained in the synthesis of chloramphenicol, is obtained by the
resolution of the corresponding racemnic base according to the process
described by VELLUZ, AMIARD AND JOLY (Bull Soc Chinm, 1953, p 342) It
has the structure HI Its physical constants are as follows: melting
point = 162-163 C; lD, = + 28 + 2 ( 2 % concentration in 0 1 normal
hydrochloric acid).
e V Q C H - l' # O d 011 (D (-) threo-l-p-nitrophenyl-2
aminopropane-1,3-diol: l,= =-28 ' + 2 ( 2 % concentration min 0 1
normal hydrochloric acid)).
In order to obtain N-3,5-dinitrobenzoyl 120 DL-proline it is possible,
for example, to effect dinitrobenzoylation of the DL-proline by any
known method or to react 3,5-dinitrobenzoyl 785,013 ( 37 %) of the
resolution reagent is recovered.
The above filtrate is acidified by means of 0.7 cc of a concentrated
hydrochloric acid.
The N 3,5 -dinitrobenzoyl-D-proline which crystallizes is then
filtered with suction, washed with a little water and dried In this
way 2 01 g ( 80 % with respect to the N-3,5dinitrobenzoyl-DL-proline

used) of crysitalline product are obtained, melting point 179o C, lal
20 = + 92 + 1 ( 0 5 % concentration in 50 % ethanol).
c) Separation of D-proline.
A solution of 1 g of the N-3,5-dinitroe benzoylo-D-proline is heated
in 10 cc of 5 N hydrochloric acid for 30 minutes, at reflux.
Filtering, evaporation to dryness in a vacuum and crystallization of
the resulting hydrochloride of D-pdine from acetone are effected The
product is then taken up, m 10 cc of water and treated during one hour
with 2 g of Amberlite I R 4 B (the word "Amberlite" being a Registered
Tradie Mark) After filtration andr evaporation to dryness in a vacuum
there are obtained 300 mg ( 80 %) of crystalline D-proline ll 20 = +
83 , 5 _+ 2 ' ( 0 5 % concentration in water).
chloride with an ester or like functional derivative of proline from
which it is then possible to regenerate easily the N-acylated amino
acid By known method as used herein is meant a method in actual use or
described in the literature on the subject.
EXAMPLE OF THE PREPARATION OF N-3,5DINITROBENZOYL-DL-PROLINE.
Operation is effected according to SAUNDERS (J Chem Soc 1938, p 1397)
2 7 g of DLproine are dissolved in 52 cc of sodium hydroxide, cooling
to O C is effected and 6.25 g of 3,5-dinitrobenzoy 1 chloride are
added The cooling mixture is removed and stirring is effected for 15
minutes at ambient temperature After filtration 5 cc of concentrated
hydrochloric acid are introduced In this way 6 8 g ( 95 %) of
N-3,5-dinitrolbenlzoylDL-proline, melting point 221-222 C, are
obtained.
The following examples illustrate the invention without, however,
limiting it; in particular, it is possible in said examples to, change
the solvent for the production of the D-()or L
(+)-threo-l-p-nitrophenyl 2 -aminopropane-1,3-diol salts, the
temperatures at which dissolution is effected, the crystallization
procedure and the time of cooling without going outside the scope of
the present invention.
EXAMPLE 1.
RESOLUTION BY MEANS OF
L-(+)-threo1-fi-NITROPHENYL-2-AMINOPROPANE-1,3DIOL AND SEPARATION OF
DAND L-PROLINES.
a) Formation of the salt of N-3,5-dinitrobenzoyl-D-prolire with
L-(+)-threo-l-pnitrophenyl-2-aminopropane-1,3-diol.
g of the above N 3,5 -dinitrobenzoylated derivative are dissolved in
25 cc of water at 700 C and 3 75 g of
L-(+)-threo-l-pnitrophenyl-2-aminopropane 1,3 -diol are added.
Cooling to 40 C is effected during 30 minutes while stirring and the
resulting precipitated salt is filtered off and is washed with a
little water After recrystallization from water and drying in a stove

at 60 C the hydrated product melts at about 1000 C, llD 20 =+ 730 _ 10
( 0 5 % concentrations in ethanol of a strength of 50 %) Yield 3 5 g (
85 %).
The salt of L-( +)-threol-p-nitrophenyl-2amiopropane 4-1,3-diol with N
3,5 dinitrobenzoyl-D-proline is a new compound.
b) Production of N 3,5 dinitrobenzoylD.-,protine.
3.5 g of the salt obtained; id a) above are treated with 7 cc of
normal sodium hydroxide solution at 40 C Dissolution of the product is
noticed and then crystallization of L-(+)threo 1 p nitrophenyl 2
amnopropane1,3-diol which is filtered with suction and washed with a
little water In this way 1 4 g d) Separation of L-proline 90 By
treating the aqueous solution from which has crystallize the salt of N
3,5 dinitrobanzoyl-D-proline with L ( + three 1 -pn
trophenyl-2-aminopropane-1,3-diol by means of 1 cc of a 35 % solution
of sodium 95 hydroxide, there is recovered as indicated under b) above
2 1 g ( 56 %) of the resolution reagent The filtrate to which has been
added 1 cc of concentrated hydrochloric acid then.
gives 2 7 g of N-3,5-dinitrobenzoy-L-proline 100 in the impure state
which is recrystallized using known methods or which is purified by
means of the salt which it gives with D-()threo 1 p nitrophenyl 2
aminopropane.
1,3-dieol (compare Example 2) 105 The product which is recuperated
from the mother liquors of recrystallizationl of
N-3,5dinitrobenzoyl-L-proline may be used as a fresh source for
racemic material to be resolved 110 The L-pline is obtained by
hydrolysis with hydrochloric acid of N 3,5 dinitrobenzoyl-L-proline as
described at c) above in the case of D-proline.
EXAMPLE 2 115
PURIFICATION OF N-3,5-DINITROBENZOYLL-PROLINB BY MEANS OF
D-(-)threo-I-p-NITROPHENYL-2AMINOPROPANE-1,3-DIOL.
2.8 g of N-3,5-dinitrob'enzoy-L-proline in 120 the impure state and
obtained according to Example 1, d) are treated at 40 C with 2 g of D
( -) threo-l- -nitrophenyl 2-aminopropane-1,,3-diol in, 14 cc of water
In this way there are obtained 3 9 g of the hydrated 125 785,013 salt
of N-3,5-dinitrobenzoyl-L-proline and of D () threo 1 p
nitrophenyl-2-aminopropane 1,3 diol, melting point = 100 C llD 20 =-73
:+ 1 ( 0 5 % concentration in 50 % ethanol) After alkaline treatment
and separation of the base followed by acidification as indicated id
Example 2, b), there are obtained 2 1 g of pure
N-3,5-dinitrobenzoyl-Lproline, melting point 179-180 C, l l 20 = 92 +
1 ( 0 5 % concentration, in 50 % ethanol).
The salt of D-()-threo-l-p-nitrophenyl-2aminopropane-1,3-diol with N
3,5 -dinitrobenzoyl-L-proline is a new compound.

* Sitemap
* Accessibility
* Legal notice
* Terms of use
* Last updated: 08.04.2015
* Worldwide Database
* 5.8.23.4; 93p
* GB785014 (A)
Description: GB785014 (A) ? 1957-10-23
Process for the resolution of dl-serine
COMPLETE SPECIFICATION
Process for the Resolution of DL-Serine
We, UCLAF, (formerly known as Usines
Chimiques Des Laboratoires Francais) of 89, rue du Cherche-Midi,
Paris, VIe, France, a
Body Corporate organised according to the laws of France, do hereby
declare the invention, for which we pray that a patent may be granted
particularly described in and by the following statement :-
The present invention relates to a process for the resolution of
DL-serine, a compound which has the formula (I). The notation"DL"
designates racemic serine which is a mixture in equal proportions of
L-serine and its enantiomorph, D-serine.
<img class="EMIRef" id="026415689-00010001" />
Serine is an-aminoss-hydroxy acid which occurs in its levo rotatory

form (L-serine) in animal metabolism. Both the D-and L-forms of serine
are constituents of various polypeptide molecules; the D-form, for
example, forms part of various polymyxines ; the L- form forms part of
viomycine, hypertensine, azaserine and numerous polypeptides of
various kinds.
As the method for the synthesis of serine leads to racemic serine, it
is necessary to have at one's disposal an easy and uncomplicated
process for the resolution which rapidly leads to D-and L-serine in
the optically pure state so that it is possible to use these isomers,
for example, in the synthesis of polypeptides containing the said
isomers.
The only method for the resolution of DLserine actually known uses as
intermediate compound the quinine salt of N-p-nitrobenzoyl-D-serine
and the brucine salt of N-pnitrobenzoyl-L-serine (c. f. E. FISCHER and
JACOBS, Ber. dtsch. chem. Ges., 1906,39, 2942). This process for the
resolution is complicated.
In Patent Specifications Nos. 24416/53 (Serial No. 745, 097), 6828/55
(Serial No.
785,013) and 6827/55 (Serial No. 785,012) the applicants have
described the use of D- (-)-and L-(+)-threo-l-p-nitrophenyl-2-
aminopropane-1, 3-diols as resolution reagents in the process for the
resolution of N-acyl-DL- tryptophanes (Patent Specification No.
745,097), DL-proline and DL-hydroxyproline respectively.
It has now been found that DL-serine may be resolved in the form of an
N-3,5-dinitrobenzoylated derivative (II), by using these resolution
reagents.
The present invention consists in a process for the production of D-or
L-serine from N3,5-dinitrobenzoyl-DL-serine, which process comprises
reacting L- (+)- or D- (-)-reo-l- p-nitrophenyl-2-aminopropane-1,
3-diol as resilution reagent with N-3,5-dinitrobenzoyl-DLserine in a
solvent medium, one of the two enantiomorphs of the racemic serine
derivative giving rise to a sparingly soluble salt with the resolution
reagent, separating this sparingly soluble salt and liberating the
N-3,5-dinitrobenzoyl-D-or L-serine therefrom by treatment with alkali
followed by acidification, and then hydrolysing it to obtain D-or
L-serine. It should be noted that the resolution reagent should be
removed from the liberated serine derivative and may then be recovered
for reuse.
Suitably, the solvent medium in which the salt formation with the
1,3-diol takes place, is an alcohol containing 6 carbon atoms or less,
e. g. methanol. Advantageously there may be added to the said solvent
medium another solvent which is miscible therewith but immiscible with
water, e. g. ethyl acetate. By this means the yield of salt with the
diol may be increased. Suitably 8-10 volumes of ethyl acetate for

every one volume of methanol may be used.
It should be noted that the process of the invention may be effected
in such a way that L- (+)-threo-l-p-nitrophenyl-2-aminopropane-1,
3-diol is reacted with a hot solution of
N-3,5-dinitrobenzoyl-DL-serine in methanol, the amount of said
1,3-diol being approximately half the amount required to salinify all
of the said DL-serine, separation of the resulting sparingly soluble
salt of N-3,5-dinitrobenzoyl-L-serine with L-(+)-threo-l-p-nitro-
phenyl-2-aminopropane-1, 3-diol is effected after cooling by
filtration or centrifuging and N-3, 5-dinitrobenzoyl-L-serine is
liberated by an alkaline treatment followed by acidification,
hydrolysis being effected in order to obtain the optically active
serine from its N-3, 5-dinitrobenzoyl derivative.
When L- (+)-threo-1-p-nitrophenyl-2aminopropane-1, 3-diol is used as
the resolution reagent in the process of the invention, a sparingly
soluble salt with N-3,5-dinitrobenzoyl-L-serine is formed and this
salt is precipitated in the crystalline state. In contradistinction,
N-3,5-dinitrobenzoyl-D-serine preferentially forms a sparingly soluble
salt with D- ()-threo-l-p-nitrophenyl-2-aminopropane-1, 3-diol.
The invention also consists in a process for the production of
optically active serine from
N-3,5-dinitrobenzoyl-DL-serine, which process comprises reacting
L-(+)-threo-l-p-nitrophenyl-2-aminopropane-1, 3-diol with a hot
solution of N-3,5-dinitrobenzoyl-DL-serine in methanol, the amount of
said 1,3-diol being approximately half the amount required to salinify
all of the said DL-serine, adding 8-10 volumes of ethyl acetate, based
on the volume of methanol, to the reaction mixture, separating after
cooling the resulting sparingly soluble salt of
N-3,5-dinitrobenzoyl-L-serine with L-
(+)-tlzreo-l-p-nitrophenyl-2-aminopropane-1, 3-diol by filtering or
centrifuging and liberating the N-3,5-dinitrobenzayl-Lserine by an
alkaline treatment followed by acidification. When the D- (-)-diol is
used as resolution reagent N-3,5-dinitrobenzoyl-Dserine forms a
sparingly soluble salt therewith, as already indicated above.
In the process of the invention alkaline treatment of-the crystalline
precipitate followed by acidification, after almost quantitative
recovery of the resolution reagent, leads to the required optically
active N-3,5-dinitrobenzoyl serine which gives the corresponding
serine by acid hydrolysis and without appreciable racemisation.
Starting with the filtrate from which the sparingly soluble salt of
the optically active serine derivative has crystallised, extraction
with an aqueous acid is effected, the agent of resolution is recovered
from the resulting aqueous acid extract with an alkali and the
optically active serine derivative having a rotatory power opposite to

the first mentioned enantiomorph is isolated from the aqueous acid
extracted filtrate by precipitation through adding a liquid
precipitation agent (e. g. petroleum ether); the enantiomorph which
has been isolated in this way, in general, is contaminated by small
quantities of racemate. This enantiomorph may be either (i) purified
by recrystallisation from a suitable solvent or by precipitation with
the corresponding threo-l-p-nitrophenyl-2-aminopropane-1, 3-diol, or
(ii) directly racemised by a known process, e. g. by alkaline
treatment of the corresponding free serine according to CRAWHALL and
ELLIOTT (Biochem. J.
(1951), 48, 237) and may be added to a new batch of racemate for
resolution. By successively alternating resolution operations and
racemisation operations the entire quantity of naturally accurring
racemate may be transformed into the required enantiomorph.
The D- (-)-and L- (+)-tJzreo-l-p-nitrophenyl-2-aminopropane-1,
3-diols, which are intermediate compounds for the synthesis of
chloramphenicol, may be obtained according to the process described by
VELLUZ,
AMIARD and JOLY (Bull. Soc. Chim., 1953, p. 342). They have the
structure (III). Their characteristics are as follows: Melting point
162163 C ; [a] D2 of the D-base-28' 2 , [a] D20 of the L-base +2S +2
(26r concentration in hydrochloric acid).
<img class="EMIRef" id="026415689-00020001" />
The following examples illustrate the invention without, however,
limiting it. In particular it is possible to effect the
N-3,5-dinitrobenzoylation by any known methods or even to react
3,5-dinitrobenzoyl chloride with an ester, an ether or another
derivative of serine from which it is then possible to easily
regenerate the N-acylated amino acid. Furthermore, it is possible, for
the production of the salts of D- (-)-or L- (+)-threo-l-p-nitro-
phenyl-2-aminopropane-1, 3-diol, to use a solvent other than the one
indicated, to vary the temperature at which dissolution is effected
and at which crystallisation is effected and the time for cooling
without going outside the scope of the present invention.
EXAMPLE 1.
PRODUCTION OF N-3, 5-DINITROBENZOYL-DL
SERINE.
6.3 g of DL-serine are dissolved in 60 cc of normal sodium hydroxide
solution, cooling is effected and 6.9 g of 3,5-dinitrobenzoyl chloride
are added. A further 10 g of 3,5-dinitrobenzoyl chloride are added
while making the reaction medium alkaline, by means of the addition of
normal sodium hydroxide solution (75 cc), 15 cc of hydrochloric acid
are added, cooling is effected, filtering with suction, the solid
washed with ether in order to eliminate the dinitrobenzoic acid, and

dried. In this way 16.7 g (93 O) of N-3,5-dinitrobenzoyl-DLserine are
obtained. The monohydrate of this substance melts at 100101 C (on a
block).
EXAMPLE 2.
RESOLUTION AND PRODUCTIONOF D-AND
L-SERINE.
(a) Formation of the salt of N-3,5-dinitro
benzoyl-L-serine with L-(+)-threo-l-p-
nitrophenyl-2-aminopropane-1, 3-diol.
First MetAlod.
10 g of N-3,5-dinitrobenzoyl-DL-serine are dissolved in 30 cc of
methanol and 4.2 g of L- (+)-threo-l-p-nitrophenyl-2-aminopropane-1,
3-diol are added at 60 C. By cooling to +10 C, 6.8 g (80%) of the
optically pure salt of N-3,5-dinitrobenzoyl-L-serine with
L(+)-threo-l-p-nitrophenyl-2-aminopropane- 1,3-diol are obtained,
melting point 160-161
C, [ < ''=+33 1 (1% concentration in water). This product is new.
Second Method.
At 60 C, 10 g of N-3,5-dinitrobenzoyl-DLserine are dissolved in 5 cc
of methanol and 4.2 g of L- (+)-threo-l-p-nitrophenyl-2-
amino-propane-1, 3-diol are added, 55 cc of ethyl acetate are then
introduced into the reaction mixture. Cooling is effected, the
resulting salt is filtered with suction ; it is then washed and dried.
In this way 8.2 g (96.5, %) of the optically pure salt of
N-3,5-dinitrobenzoyl-L-serine with L- (+)-threo-l-p-nitro-
phenyl-2-aminopropane-1, 3-diol, are obtained.
(b) Production of N-3,5-dinitrobenzoyl-L
serine.
8.2 g of the above salt are dissolved in 16.5 cc of normal sodium
hydroxide solution. The L- (+)-threo-l-p-nitrophenyl-2-aminopro-
pane-1, 3-diol which crystallises is filtered with suction and is
dried. In this way, 3.1 g (74%) of the resolution reagent are
recovered. After having acidified the filtrate with 1.7 cc of
concentrated hydrochloric acid, the N-3,5-dinitrobenzoyl-L-serine
crystallises. Filtration with suction is effected and the solid is
washed and dried. In this way 4.5 g (90% of the
L-isomer based on the N-3,5-dinitrobenzoyl
DL-serine used as starting material) of crystalline product are
obtained. The monohydrate has a melting point of 110112 C, [ff] D20=
+23. 5 +. 1 (1% concentration in 50% ethanol).
(c) Separation of L-serine.
During one hour at reflux there is heated a solution of 4.3 g of
N-3,5-dinitrobenzoyl-Lserine in 60 cc of five times normal
hydrochloric acid. After filtration, evaporation of the filtrate to

dryness is effected in a vacuum and the resulting hydrochloride of
L-serine is recrystallised from acetone. The product is taken up in 1
cc of water, 1.4 cc of aniline and 10 cc of absolute alcohol are
added. After cooling, 1.3 g (90%) of L-serine in the crystalline state
and optically pure, melting point 228 C, [] D20=+15 +1 (4%
concentration in normal hydrochloric acid), result.
(d) Separation of D-serine.
The ethyl acetate/methanol solution from which the salt of
N-3,5-dinitrobenzoyl-Lserine with L- (+)-threo-l-p-nitrophenyl-2-
aminopropane-1, 3-diol has crystallised (see
Example 2 (a), second method) is extracted with 10 cc of 0. 5 normal
hydrochloric acid and then with 5 cc of water. The aqueous solutions
are combined and made alkaline with normal sodium hydroxide solution.
In this way 0.4 g (10%) of the resolution reagent are recovered. The
organic phase is then concentrated and petroleum ether is added. In
this way 4.85 g (97% of D-isomer based on the
N-3,5-dinitrobenzoyl-DL-serine used as starting material) of
N-3,5-dinitrobenzoyl-D-serine is recovered which may easily be
purified by recrystallisation. The crude product melts at 109111 C, []
D2 =-22 ~1 (1% concentration in 50% ethanol). The corresponding
D-serine is obtained by hydrolysis with hydrochloric acid as indicated
at (c) above in the case of L-serine.
EXAMPLE 3.
PRODUCTION OF N-3, 5-DINITROBENZOYL-D-
SERINE BY MEANS OF D- (-)-THREO-1-p-
NITROPHENYL-2-AMINOPROPANE-1, 3-DIOL
N-3,5-dinitrobenzoyl-DL-serine is treated
with D- (-)-threo-l-p-nitrophenyl-2-aminopropane-1, 3-diol as
indicated at (a) in Example 2 In this way the salt of
N-3,5-dinitrobenzoyl
D-serine with D- (-)-threo-l-p-nitrophenyl-2- aminopropane-1, 3-diol
is obtained, melting point 160161 C, [ff] D20=-33 +1 (1l%
concentration in water). This product is new.
It leads, on treatment as described in Example 2 (b), to
N-3,5-dinitrobenzoyl-D-serine in the optically pure state. The
monohydrate has a melting point of 110112 C, [] D20=
-23.5 1 (1 % concentration in 50 % ethanol) ; then, as described in
Example 2 (c), there is obtained D-serine, [a] 21 =-15'
1 (4% concentration in normal hydrochloric acid). The
N-3,5-dinitrobenzoyl-Dserine has not hitherto been described.
What we claim is :-
1. A process for the production of D-or
L-serine from N-3,5-dinitrobenzoyl-DLserine, which process comprises
reacting L (+)-or D- (-)-threo-l-p-nitrophenyl-2- aminopropane-1,

3-diol as resolution reagent with N-3,5-dinitrobenzoyl-DL-serine in a
solvent medium, one of the two enantiomorphs of the racemic serine
derivative giving rise to a sparingly soluble salt with the resolution
reagent, separating this sparingly soluble salt and liberating the
N-3,5-dinitrobenzoyl-D- or Lserine therefrom by treatment with alkali
followed by acidification, and then hydrolysing it to obtain D-or
L-serine.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* 5.8.23.4; 93p
* GB785015 (A)
Description: GB785015 (A) ? 1957-10-23
Improvements in or relating to method of preparing agglomerate calcium
phosphate andthe product resulting from said method
A:T = rA:
785,015 S 22 > Date of Application and filing Complete Specification
June 17, 1955.
No.17540/55.
X - Application made in United States of America on June 18, 1954.

Complete Specification Published Oct 23,1957.
Index at acceptance: Class 1 ( 3), Al(D 37: G 47 D 37) International
Classification: -C O olf.
C Oi MIPLETE SPECIFICATION
Improvements in or relating to method of preparing Agglomerate Calcium
Phosphate and the Product resulting from said method We, INTERNATIONAL
MINERALS & CHEMICAL CORPORATION, a corporation organised under the
laws of the State of New York, -United States of America, of 20, North
Wacker Drive, City of Chicago, State of Illinois, -United States of
America, do hereby declare the invention, for which 'we pray that a
patent may be granted to us, and the method by which it is te be
performed, to be particularly described in and by the following
statement: -
This invention relates to the preparation of agglomerated phosphates
lMore particularly it relates to a method of treating animal feed
grade powdered dicalcium phosphate to eliminate dusting.
The present invention provides a nonhygroscopic agglomerate animal
feed supplement phosphate product which comprises substantially
fluorine-free dicalcium phosphate material bonded together with
sufficient acidic calcium-contaihing phosphatic material to give a
final product having a Ca 0/P,05 mol ratio in the range of between 1
55:1 0 ' and 1 95:10.
The present invention also provides a method of producing
honhygroscopic agglomerated dicalcium phosphate which comprises
admnixing dicalcium phosphate having a particle size less than 80 mesh
with an acidic calcium-containing phosphatic soluttions in proportions
to produce a na O/P 2,O mol ratio in the final product in the range
between 1 55:1 0 ' and 1.95:1 0, and drying the mixture.
Animal food supplement material, i e, dicalcium phosphate, is
precipitated from defiuorinated phosphate solution by reaction with
lime or calcium carbonate This dicalcium phosphate material
precipitates as fine small crystals which with any attrition during
drying are reduced to a low bulk density powder most of whose
partidles are of less than 100 mesh particle e 3 s6 d 1 size This low
bulk density powder or dust presents a serious handling problem both
in the manufacturing plant or in an animal food processing plant.
It is a primary object of this invention 50 to overcome the
disadvantages and shortcomings of animal food supplement phosphate
products heretofore manufactured.
It is another object of this invention to provide a granular animal
food grade 55 dicalcium phosphate, It is still another object of this
invention to provide a product containing both water soluble and
citrate soluble calcium phosphate components which is non 60 dusting.
It is a further object of this invention to provide a method of

treating dicalcium phosphate with acidic phosphatic solutions to
produce a dense agglomerated pre 65 dominantly dicalcium phosphate
material.
These and other obj ects will be apparent to those skilled in the art
from the following description.
In producing the nonhygroscopic 70 agglomerate phosphate products of
the present invention dicalcium phosphate is reacted with aqueous
solutions of water soluble calcium-containing acidic phosphatic
materials, the proportions of 75 reactants being such as to render the
mixture an agglomerate mass of Ca O 1 P 20, mol ratio of between 1
55:1 0 and 1.95 1 0 The agglomerate mass after reaction is dried under
temperature con 80 ditions low enough to maintain the phosphates in
the ortho-phosphate state.
The granular phosphatic products of the present invention consist
predominantly of crystals of dicalcium phosphate 85 bonded together
with a minor amount of predominantly water soluble monocalcium
phosphate.
In the production of these materials the ratio of dicalcium phosphate
to phos 90 , 785,015 phatic solution must be maintained within since
this apparently results in a more specific-limits Too small a
quantity-of -complete-reaction.
phosphatic binder is almiost as ineffective The following examples are
given as for agglomeration of dicalcium phosphate illustrative of-the
preferred embodiment, as water The latter mnaterial produces but the
invention is not to be construed as 70 agglomerates in the wet form,
-but upo limited t 6 the details set forth therein.
drying the agglomerates dust off and: EXAIPLB, I break down to the
original small grain About 60 tons per hour of Florida phosparticles
under normal handling and; phate rock are ground to a particle size,
shipping conditions On the other hand, approximately 52 % of which are
passed 75 -if too large a quantity of aqueous phos _through a 200 mesh
standard screen.
phatic solution is added, the agglomerates This rock analyzed about 68
% bone phoswill in addition to coating the dicalcium phate of lime The
ground rock was mixed phosphate with binder become exteriorly with
about 36 tons per hour of 98 % sulcoated with hygroscopic aon
ocalciuim fui Hc acid added as approximately 53 Be 80 phosphateand
present ahandling problem aqueous solution The mixture was of entirely
dierent nature, i e, hygro thoroughly agitated for about one minute,
scopicity of produicts The granular final after which it was
discharged onto a conproducts in order to exhibit the proper tinuous
belt provided with exhaust means cohesive character must have a Ca O/P
205 for gases such as sulfur dioxide, silicon 85 -mel ratio -in the
range of between tetrafluoride, and the like adjacent the 1.95:1 O and

1 55: 1 0, and preferably in point of discharge of slurry onto the
belt.
the range of between 1 75:1 O ' and The belt length and its speed were
such 1.9:1 O that the mix remained on the belt approxiAccordingly the
method of producing mately 20 minutes The discharge from 90 the
granular product contemplates mix the belt was stored in a pile for
about 30 ming and reacting fine particle size dicaldays cium phosphate
material whose particle The stored material was then removed size is
generally of less than 100 mesh par from storage, broken up, and
tidele size and has a Ca O /PO 5 mol ratio sufficient water added to
give 95 in the range of betweek 2 0:1 0 and a slurry of about 35 %
undis2.3:1 0 with an aqueous monocalcium -solved solids The slurry was
subjected to prosphate solution, and preferably with four stages of
continuous countercurrent fluorine-free predominantly monocalcium
-leaching and filtering, the final filtrate phosphate solution whose
Ca O/I Pi O mol being a leached solution containing about 100 ratio is
in the range of between 0 20: 1 0 30 % dissolved solids and being of
approxiand 1 O:L 1 O These reactants are com mutely 320 Be gravity The
d Iiscar led mingled in proportions to give a Ca O/ -tailings
contained about 2-l% of the 37: % PO O mol ratio for the final product
in the total P 205 in the original rock The range of between 1 55:1 0
and 1 95:1 0, filtrate from the leaching operation was 105 and are
agitated to effect an intimate mix further processed by adding
approxiing This reacted mixture is then dried mately 4 7 tons per hour
of limestone or as in a rotary kiln at temperatures in the its
equivalent in calcium hydroxide range of 90 Oto 120 O added in the
form of hydrated Moonocalcium phosphate has the for lime or other
suitable calcium 110 mula -Ca El(P O 04)2 and corresponds to a oxide
source material After slurrying for Ga O/PE 2 Q mol ratio of 1 0):1 O
Pre approximately 3 ( minutes, the slurry was -dominantly monocaleiumn
phosphate solu filtered on a drum filter to remove pretions have a Ca
O/I 2, moi ratio less than cipitated solids such as calcium fluoride
-10 1 O In the leaching of superphos aluminum phosphate, iron
phosphate, as 115 phaotes, for example, aqueous solutions are well as
any unreacted limestone.
obtained consisting predominantly of The filtrate from the slurrying
or monocalcium phosphate and having a defluorination step analyzed as
follows:
Ca O/P 2 00mol ratio generally ih the Parts by range of -0 25:1 0 to O
h 7: 1 0 weight 120 Predominantly-monocalcium phosphate PO 100
solutions react with dicalcium phosphate Fluorine O 2 in the presence
of some moisture Accord Ga Oe 37 5 ingly, if the commingling or mixing
is Solids 160 sufficiently thorough, the phosphatic solu Water 750 125
tions may be mixed with wet dicalcium Total 910 phosphate such as the

forim in which it is The defluornated extract totalling -removed from
the filters Preferably, approximately 136 tons per hour was split
however; -phosphatic-sol-utions are mixed into two streams havihg a
ratio of 80 % to with water-wetted dicalmm phosphate 20 % by weight
130 785,61:5 On a parts by weight basis comparable to the analysis of
the feed being delivered to the dicalcium phosphate precipitation, the
minor portion split -from the main stream corresponds to a feed as
follows: Parts by weight P 2 05 26 6 Ca O 10 Solids 42 6 Water 200
Total 242 6 This portion of the solution was heated to boiling, i e
about 215 F, and held at that temperature for about 10 mihutes A
precipitate was formed upon heating and was recovered by filtration
These solids analyzing Parts by weight P 205 - 6 6 Qa O 5.
Solids 13 2 Water 3 3 Total 16 5 were mixed with the dicalcium
phosphate being dried in the Nichols-Hlerreschoff hearth furnace.
Hllot filtrate from the heating and filtering operation ahalyzed as
follows:Parts by weight P 205 20 c'ao 4 8 Solids 29 4 Water 197 Total
226 4 This hot filtrate was then concentrated by evaporation which
removed 163 parts by weight of water leaving a concentrated solution
which analyzed as follows:Parts by weight P 20 O 20 Ca O 4 8 Solids 29
4 Water 34 1 Total 63 5 The major portion of the defluorinated
extract, totalling approximately 110 tons per hour of defiuorinated
reactor, was treated with approximately 11 3 tons per hour of calcium
carbonate, i e Ocala limestone, to precipitate dicalcium phosphate The
resultant slurry was filtered and the solids dried in a Nichols-
Herreschoff multiple hearth furnace at a temperature of about 110 O
This filtered dicalcium phosphate was mixd with the precipitated
solids filtered from the beat treated portion of the extract.
Dry dicalcium phosphate received from the Nichols-l Herreschoff dryer
analyzed a, follows:P 2,0 Ca O Solids Water Total Parts by weight - 69
This dry product was mixed with the above described concentrate in a
pug mill in proportions to give a mixture analyzing as follows:Parts
by weight P 20 10,0 C Ga O- 73 7 Solids 200 Water 34 Total 234 This
mixture was dried in a rotary dryer at 1 i 00 'C The dry product was
screened on a 20 mesh size standard screen Over size material was
crushed and the crushed material returned to the screen The 20 mesh +
80 mesh size particles were recovered as product and analyzed as
follows:Parts by weight P 205 100 Gao 73 7 Solids 200 Water Total 200
The original dry dicalcium phosphate material delivered by the
Nichols-Herreschoff dryer was of particle size such that approximately
100 %/o would pass through an 80 mesh size standard screen The final
product has a Ca O/PO 26 moel ratio of approximately 1 87.
E Xm P Lw, II 105 Predetermined equal quantities of the above
described dry dicalcium phosphate material, i e 150 ' grams, were each
mixed with quantities of the above described concentrate solution so

as to produce mix 110 tures containing 21 %, 25 %, 28 %, and 31 %,
respectively, of the total P 205 content of the mixture as
mono-calcium phos ' phate binder Each sample was dried in an oven at a
temperature of approxi 115 mately 110 C for approximately two hours A
150 gram portion of each sample was then removed from the oven and
placed in a bag within a six inch diameter ball mill and the mill
rotated for approxi 120 mately ten minutes Each sample was then
removed from its grinding mill and the product screened on an 80 mesh
size standard screen to determine the quantity of fines produced
Results were as 125 follows:785, 015 % P 20 as mono-calcium :
phosphate binder 2 1 2528 31 Our copending application No.
17541/55 (Serial No 785,016) describes andi claims a method of
producing nonhygroscopic agglomeratedl dicalcium phosphate which
comprises admixing dicalcium phosphate having a particle size of less
than 80 mesh with solutions of free acids in proportions to produce a
Ca O/P 205 mol ratio in the final product in' the range between 41
55:1 O and 1.95:1 0, huand-drying theamixture.
What we ciaim is:
1 A noiihygroscopic agglomerate animal feed supplement phosphate
product which comprises substantially fluorine-free dicalcium
phosphate material bonded together with sufficient acidic
calcium-coitaining phosphatic material to give a final product having
a Ca O/PQ O mol ratio in the range of between 1 55:1 O and 1 95:1 0.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* 5.8.23.4; 93p
* GB785016 (A)
Description: GB785016 (A) ? 1957-10-23
Improvements in or relating to method of producing agglomerate calcium
phosphate mixtures

PATIENT SFE Mi FICATON
785,016
Date of Application and filing Complete Specification June 17, 1955.
No 17541/55.
Application made in United States of America on June 18, 1954.
Complete Specification Published Oct 23, 1957.
Index at Acceptance: -Class 1 ( 3), A 1 (D 37: G 47 D 37).
International Classification: C 0,.
Improvements in or relating to method of Producing Agglomerate Calcium
Phosphate Mixtures We, INTERNATIONAL MINERALS & CHEMICAL CORPORATION,
a corporation organised under the laws of the laws of the State of New
York, United States of Armerica, of 20, North Wacker Drive, City of
Chicago, State of Illinois, United States of America, do hereby
declare this invention, for which we pray that a patent may be granted
particularly described in and by the following statement: This
invention relates to the preparation of agglomerated phosphates More
particularly, it relates to a method of treating animal feed grade
dicalcium phosphate powder to eliminate dusting.
The present invention provides a method of producing nonhygroscopic
agglomerated dicalcium phosphate which comprises admixing dicalcium
phosphate having a particle size of less than 80 mesh with solutions
of free acids in proportions to produce a Ca O/P O, mol ratio in the
final product in the range between 1.55: 1 O and 1 95: 1 0, and drying
the mixture.
Animal food supplement material, i e dicalcium phosphate, is
precipitated from fluorine-free phosphate solution by reaction with
lime or calcium carbonate This dicalcium phosphate material
precipitates as fine small crystals which with any attrition during
drying are reduced to a low bulk density powder, most of whose
particles are of less than 100 mesh particle size This low bulk
density powder or dust presents a serious handling problem, both in
the manufacturing plant and in an animal food processing plant.

It is a primary object of this invention to overcome 'ide
disadvantages and shortcomings of animal food supplement phosphate
products heretofore manufactured.
It is another object of this invention to provide a granular or
agglomerate animal food grade dicalcium phosphate.
It is still another object of this invention to provide a product
containing both water soluble and saturated soluble calcium phoslPric/
3 s 6 d I phate components which are nondusting.
It is a further object of this invention to provide a method of
treating dicalcium phos 50 phate with solutions of free acids to
produce a dense agglomerated predominantly dicalcium phosphate
material.
These land other objects of the instant invention will be apparent to
those skilled in 55 the art from the following description.
In producing the nonhygroscopic agglomerated phosphate products of the
instant invention, feed grade dicalcium phosphate is reacted with
aqueous solutions of free acids, 60 the proportions of reactants being
such as to render the mixture an agglomerate mass of Ca O/P O Q, mol
ratio of between 1 55:1 0 and 1.95:1 0, this range being exclusive of
any Ca O content tied up as the calcium salt of 65 the acid used such
as calcium sulfate The agglomerate mass, after mixing and reaction, is
dried to temperature conditions low enough to maintain the phosphate
in the ortho-phosphate state 70 Aqueous acid solutions which enter
into a reaction with dicalcium phosphate are phosphoric acid, sulfuric
acid, hydrochloric acid, tartaric acid, or mixtures thereof The
reaction of the acids other than straight phosphoric acid 75 with
dicalcium phosphate results in the formation of binders in situ
through the production of phosphoric acid or binders by reaction
between dicalcium phosphate and the acid or through the reaction
between added mono 80 calcium phosphate solution and an acid, which in
turn reacts to form a calcium phosphate material Phosphoric acid has
the advantage that less acid needs to be added, since phosphoric acid
is present for immediate reaction 85 to form a calcium phosphate
material, rather than having to form phosphoric acid as an
intermediate step Mixtures of other acidic materials such as HPO 4
with sulfuric acid has the advantage that it gives control over the 90
P 20,O content of the final product.
The agglomerate phosphatic products of the instant invention consist
predominantly of crystals of dicalcium phosphate bonded 785,016
together with a minor amount of predominantly water soluble
monocalcium phosphate.
In the production of these materials, the ratio of dicalcium phosphate
to binder solution must be maintained within specific limits Too small
a quantity of phosphatic binder is almost as ineffective for

agglomeration of dicalcium phosphate as water The latter material
produces agglomerates in the wet form, but upon drying, the
agglomerates dust off and break down to the original small grain
particles under normal handling and shipping conditions On the other
hand, if too large a quantity of phosphatic binder is added or
produced, the agglomerates will, in addition to coating dicalcium
_phosphate with binder, become masses exteriorly coated with
hygroscopic monocalcium phosphate and present a handling problem of
entirely different nature, i e, hygroscopicity of products The
agglomerates, in order to exhibit the proper cohesive character, must
have a Ca O/Po O.
mol ration in the range of between 1 95:1 O and 1 55: 1 0, and
preferably in the range between 1 75:1 0 and 1 9:1 0.
Accordingly, the method of producing granular products contemplates
mixing and reacting dicalcium phosphate whose particle size is
generally such as to pass through an 80 mesh size standard screen and
a major portion of which will pass through a 100 mesh size standard
screen with an aqueous solution of free acid The reactants are
thorougly mixed in proportions to give a Ca O/P O, mol ratio for the
final product in the range between 1.55:1 0 and 1 95:1 0, and
preferablyin the range between 1 75:1 0 and 1 9:1 0, and the reacted
mixture dried in a rotary kiln at ternmperatures in the range of 90 C
to 120 C.
The reaction between acid and dicalcium phosphate forms monocalcium
phosphate, either directly or through the formation of the
intermediate free phosphoric acid Acid solutions react with the
dicalcium phosphate in the presence of some moisture Accordingly, if
the commingling or the mixing is sufficiently thorough, the acid
solutions may be mixed with wet dicalcium phosphate such as the form
in which it is removed from the filter as hereinafter described
Preferably, however, acid solutions are mixed with a water wetted
dicalcium phosphate, since this apparently gives a more complete
reaction.
The following examples are given as illustrations of the invention,
but the invention is not to be construed as limited to the details set
forth therein.
EXAMPLE I
About 60 tons per hour Florida phosphate rock is ground to a particle
size, approximately 52 % of which passed through a 200 mesh size
standard screen This rock analyzed approximately 68 % B P L The ground
rock was mixed with about 36 tons per hour of about 98 %? sulfuric
acid added as approximately 530 Be aqueous solution The mixture was
thoroughly agitated for about one minute after which it was discharged
onto a continuous belt provided with exhaust means for gases such as

sulfur dioxide, silicon tetrafluoride, and the like The discharge from
the belt was stored in a pile for about 30 days.
The stored material was then removed from storage, broken up, and
sufficient water added to give a slurry of about 35 %, undissolved
solids The slurry was subjected to continuously countercurrent
leaching and filtering, the final filtrate being a leached solution
containing about 30 % dissolved solids and being of about 32 Be
gravity The discarded tailings contained about 2 5 % of the 30 %,
total P O, in the original rock The filtrate from the leaching
operation was further processed by adding approximately 4 7 tons per
hour of limestone After slurrying for approximately minutes the slurry
was filtered on a drum filter to remove precipitated solids, such as
calcium fluoride, aluminium phosphate, iron phosphate, as well as any
unreacted limestone.
The defucrinated extract totaling approximately 136 tons per hour was
reacted with additional, approximately 14 7 tons per hour, calcium
carbonate to precipitate dicalcium phosphate The resultant slurry was
filtered and the solids dried in a Nichols-I Herreschoff multiple
hearth furnace at a temperature of about 110 C The dry dicalcium
phosphate was a fine powder substantially 100 %/ of which passed
through an 80 mesh size standard screen.
EXAMPLE II
Five portions of the dicalcium phosphate material prepared as
described in Example I were segregated and treated as follows:To each
sample was added, on a unit weight 105 basis of one hundred parts by
weight of dicalcium phosphate, 5 %, 7 5 %, 10, 12 5 i%, and 17 % by
weight, respectively, of sulfuric acid, calculated on a 98 % sulfuric
acid basis.
Each of these samples was fed to a pug mill 110 and the mixing carried
on for approximately minutes The pug mill material was then dried in
an oven held at a temperature of approximately 110 C for 2 hours Each
of the dried samples was then introduced into a 115 ball mill and the
materials subjected to the action of approximately one-half inch
diameter flint rock balls for 10 minutes Material was then removed
from the ball mill and screened on an 80 mesh size standard screen to
deter 120 mine the proportion of the sample which would pass through
the screen Results were as follows:% Sulfuric acid 7.5 12.5 ' Passing
Through an Mesh Size Screen 125 42 29 2.5 Substantially O 785,016
EXAMPLE III
Five portions of the dicalcium phosphate material prepared as
described in Example I were segregated and treated as follows:To each
sample was added, on a unit weight basis of one hundred parts by
weight of dicalcium phosphate, 8 5 %, 12 7 %, 17 % and 21 % by weight,
respectively, or phosphoric acid, calculated on a 98 % phosphoric acid

basis Each of these samples was fed to a pug mill and the mixing
carried on for approximately 10 minutes The pug mill material was then
dried in an oven held at a temperature of approximately 110 C for
about 2 hours Each of the dried samples was then introduced into a
ball mill and the materials subjected to the action of flint rock
balls for 10 minutes Material was then removed from the ball mill and
screened on an 80 mesh size standard screen to determine the
proportion of the sample which would pass through the screen Results
were as follows:% Passing Through an % Phosphoric Acid 80 Mesh Size
Screen 8.5 12 12.7 6 12.7 (double mixed) 2 17 2 5 21 0 1 Prolonged
mixing improves results.
EXAMPLE IV
Five portions of dicalcium phosphate material prepared as described in
Example I were segregated and treated as follows:To each sample was
added on a unit weight basis or one hundred parts by weight of
dicalcium phosphate, 10 parts by weight, 12 5 parts by weight, and 17
parts by weight, respectively, of a mixture of acids consisting of 10
parts by weight phosphoric acid and 7 parts by weight of sulfuric
acid; each of the acids being calculated on a 98 % purity acid basis
Each of these samples was fed to a pug mill and the mixing carried on
for approximately 10 minutes The pug mill material was then dried in
an oven held at a temperature of approximately 110 C for approximately
2 hours Each of the dried samples in turn was then introduced into a
bag within a 6 inch diameter ball mill and the material subject to
ball mill action for 10 minutes The ball mill material was then
removed from the ball mill and screened on an 80 mesh size standard
screen to determine the proportion of the sample which would should
pass through the screen Results were as follows:% by Weight of Acid
Mixture 10 12.5 % Passing through an Mesh Size Screen 8 4 0.5 EXAMPLE
V
Dicalcium phosphate material prepared as described in Example I was
treated as follows: 65 Defluorinated extract prepared as described in
Example I (a mixture of monocalcium phosphate and phosphoric acid) was
heated to F for one hour and the precipitated solids removed by
filtering The solids-free 70 extract was concentrated from
approximately 11 % POA content to approximately 20 8 % Po Q,
concentration.
To each approximately 4 4 units by weight of the above dicalcium
phosphate material of 75 47.1 % PO, content being agitated in a pug
mill was added approximately 0 25 units by weight of concentrated
extract of 20 8 % P 2,O, 0.21 units by weight of 93 % surfuric acid
and 0.4 units by weight of recycled fine product 80 of -80 mesh screen
size The damp mixture from the pug mill was dried in a rotary drier at
a temperature of approximately 110 C.

where it agglomerates The dry discharged material from the kildn was
screened to remove 85 + 14 mesh size and -35 mesh size material.
The + 14 mesh size material was pulverized in a hammer mill and
screened on a 35 mesh screen, the + 35 mesh size material being
conveyed to product storage The -35 mesh size 90 material was mixed
with the -80 mesh size material from the original product screening
and recycled to the pug mill for addition in the proporations
described This fraction of -14 + 80 mesh size material is the hard 95
agglomerated product of commerce.
Our copending Application No 17540/55 (Serial No 785,015) describes
and claims a nonhygroscopic agglomerate animal feed supplement
phosphate product which com 100 prises substantially fluorine-free
dicalcium phosphate material bonded together with sufficient acidic
calcium-containing phosphatic material to give a final product having
a Ca O/PRO 5 mol ratio in the range of between 105 1.55: 1 0 and 1
95:1 0.
Application No 17540/55 (Serial No.
785,015) also describes and claims a method of producing
nonhydrogroscopic agglomerated dicalcium phosphate which comprise
admix 110 ing dicalcium phosphate having a particle size less than 80
mesh with an acidic calcium-containing phosphatic solution in
proportions to produce a Ca O/PO, mol ratio in the final product in
the range between 1 55:1 0 and 1 95: 115 1.0 and drying the mixture.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* 5.8.23.4; 93p
* GB785017 (A)
Description: GB785017 (A) ? 1957-10-23
Pressing of bricks, briquettes and the like

Inventor: NORMAN BARDSLEY Date of filing Complete Specification Jan
25, 1954.
f, > ', " ? ' ' Application Date Oct 23,1952.
Complete Specification Published Oct 23, 1957.
Index at Acceptance: -Class 87 ( 2), A 1 P 1 B. International
Classification: -B 28 b.
Pressing of Bricks, Briquettes and the like We, SUTCLIFFE, SP/EAIMAN
AND COMP.NY, LMI Tir ED, a British joint-stock Corporation, of Leigh,
Lancashire, do hereby declare the invention, for which we pray that a
patent may be granted to us, and the method by whichl it is to be
performed, to be particularly described in and by the following
statement:-
The invention relates to a press for the manufacture of bricks,
briquettes and the like.
In the manufacture of bricks, briquettes and the like, it is known to
provide presses which impart two pressings or pressures of different
intensity to brick or briquette material in a mould, for the purpose
of increasing the density of the bricks or briquettes and of reducing
the tendency of the bricks or briquettes to laminate.
Generally, such presses have either been provided with two separate
pressing mechanisms or the two pressures have been applied at two
different positions around a rotary table press.
It is an object of the invention to provide a press having simple and
reliable means for imparting two pressures of different intensity to
the material being pressed in the mould.
According to the invention, a press for the manufacture of bricks,
briquettes or the like is provided with means for applying at least
two pressings through the same plunger to material in a mould of the
press, and with means comprising a movable taper plate to alter the
effective stroke of the press plunger whereby the pressure on the
material in the mould in the second pressing is greater than in the
first pressing.
Advantageously, a second taper plate is provided integral with the
pressing foot of the press, the movable taper plate being adapted to
slide on the taper of the second or fixed taper plate Alternatively
the second taper plate may be secured to lPrice 3 s 6 d l 785017 No
26683/52.
the base of the press plunger By varying the distance by which the two
taper plates overlap, or by the use of a series of taper plates having
different angles of taper, the 50 effective stroke of the plunger or
plungers may be made shorter or longer and the pressures on the

material in the mould may be varied accordingly Thus the pressure in
the second or subsequent pressing 55 may be made greater than the
pressure in a preceding pressing of the material in the mould.
Preferably, the press is of the type ih which the moulds are formed 60
within a rotary table which is driven through a pawl and ratchet
mechanism Means are provided according to the invention whereby the
table is rotated to bring a further mould 65 or set or moulds into the
pressing position at every alternate stroke of the press, thus
permitting the two pressings to be applied to each brick or briquette
produced Where more than two pressings are to be applied 70 to the
material in each mould, then means are provided to cause the
press-table to dwell whilst the requisite number of pressings is
carried out The dwell of the table is preferably effected by
disengaging the 75 pawl from the ratchet.
According to the invention furthermore, a cam mechanism is provided to
synchronise and interlock the movement of the taper plate with the
rotation of the 80 press-table and the reciprocating movement of the
pressing foot, the table being caused to dwell whilst the pressing
foot is actuated two or more times to give a corresponding number of
pressings to the 85 material in each mould.
The cam mechanism advantageously comprises a cam drum mounted on a
rotary shaft and provided with a series of circumnferential cam
surfaces, and a series of 90 cam followers which control the means
effecting the movements of the taper plate 785,017 and the means
determining the rotation of the press-table The rotary shaft of the
cam drum is advantageously driven from the main crankshaft of the
press, thereby permitting the movement of the taper plate and the
rotation of the press-table to be readily synchronised with the
reciprocating motion of the pressing foot and the plungers Where the
material in each mould is to be given two pressings, the drive from
the main crankshaft of the press to the rotary shaft of the cam
mechanism will be through a 2:1 reduction gear.
The means for effecting movement of the taper plate and the means for
determining the rotation of the press-table may comprise air cylinders
and air valves and/or electrical circuits for energising solenoids.
The apparatus of the invention is particularly adapted to the pressing
of nonplastic bricks or briquettes including bricks or briquettes of
clinker, iron ore, concrete, refractory material and sand lime For
example, a refractory brick material having a moisture content of
about 6 % and being of a fairly coarse grading of about '/I", is
particularly suitable for pressing in the press of the invention.
Oe construction of apparatus according to the invention, in its
application to a press of the rotary table type, is diagrammatically
illustrated by way of example in the accompanying drawings, in

which:Figure 1 is a side elevation of the mechanism for operating the
sliding, taper plate; Figure 2 is a plan view of the mechanism shown
in Figure 1; Figure 3 is an end elevation of the mechanism shown in
Figure 1; Figure 4 is a side elevation of the mechanism controlling
the rotation of the rotary table;
Figure 5 is a plan view of the' mechanism shown in Fitgure 4; Figure 6
is a plan view of control mechanism of the air valves; Figure 7 is a
longitudinal section on the line A-A of Figure 6; Figure 8 is a
transverse section of Figure 6; and Figure 9 is a valve cycle diagram.
A pressing foot 1 is mounted on a crosshead 2 disposed below the
rotary table (not shown) of a power-driven press, the crosshead 2
being adapted for reciprocation in a vertical direction in known
manner to apply pressure, through one or more plungers (not shown), to
the material in the moulds of the rotary press table.
The pressure on the material in the moulds L is applied upwardly
through the plunigers disposed in guides, the pressure being resisted
by a pressure block resting on the upper surface of the table of
moulds A plate 3 (hereinafter referred to as the fixed 70 taper plate)
is secured to the upper surface of the pressing foot 1 in such manner
that the upper surface of the fixed taper plate 3 is inclined to the
horizontal.
A wedge or taper plate 4 is provided to 75 rest with its taper face on
the upper surface of the fixed taper plate 3, the taper plate 4 being
adapted to slide or ride over the fixed taper plate 3 between lateral
guide plates 5 The upper surface of the 80 taper plate 4 is
substantially horizontal and during upward travel of the pressing foot
1 it comes to bear, either directly or indirectly, on the outer end or
ends of the press plunger or plungers The upper sur 85 face of the
taper plate 4 may be advantageously overlaid by a plate 14 of a heavy
duty alloy.
Movement of the taper plate 4 over the surface of the fixed taper
plate 3 is 90 effected through a cranked operating lever 6 which is
pivotally mounted on a pin 7 carried in a bracket pivoted on the
pressing foot 1 One arm of the lever 6 is provided with a slot 13 in
which a pin 12 pro 95 vided on the taper plate 4 is engaged, whilst
the other arm of the lever 6 is pivotally connected to the piston rod
S of a double-acting air cylinder 9 The air cylinder 9 is supported at
its upper end 100 by trunnions 10 which are mounted in brackets 11
provided on the pressing foot 1 Compressed air is passed into or
released from the cylinder 9 through lines 15 and 16, the line 15
being connected to the top 105 of the cylinder and the line 16 to the
base of the cylinder A number of limit stops 17 are provided on a
shaft 17 a provided with a head 17 b to limit the rotary movement of
the operating lever 6 The stops 110 17 comprise a series of short

cylinders 17 e of different diameters mounted adjacent to one another
on the shaft 17 a, longitudinal movement of the shaft 17 a serving to
bring any one of the cylinders 17 c into 115 the plane of the lever 6
to function as a limit stop The head 17 b is provided with a peg 17 c
which is adapted to be received in a series of holes 17 ( 1 of
different depths disposed in one of the brackets in which 120 the
shaft 17 a is mounted By manual rotation of the head 17 b, the peg 17
c may be brought into alignment with one of the holes 17 d and upon
longitudinal movement of the shaft 17 a the peg 17 c may be 125 pushed
home in the particular hole 17 d to bring the corresponding stop lee
into the plane of the lever 6.
The flow of air into and out of the cylinder 9 is controlled by valves
which 130 7865,1 i 7 are actuated by the cam mechanism hereinafter
described.
The rotary motion of the press-table is operated in synchronism with
the plunger pressing operation in known manner by means of a crank
(not shown), a connecting rod 20 G, and a pawl and ratchet mechanism,
the connecting rod 20 a being secured, at the end remote from the
crank, by means of a pin and swivel block to the catch-plates as shown
in Figure 5 A catch pawl 21, which is also attached by a pmin to the
catch-plates, is normally engaged with a catch or ratchet wheel 20 '
which is secured on the vertical spindle 20 b of the table of moulds A
spring 22 urges the catch pawl 21 into engagement with the teeth of
the catch wheel 20, and whilst this engagement is maintained an
intermittent rotary motion in one direction only is given to the
rotary table by the pull of the connecting rod 20 a, to bring the
moulds into position for pressing On the return stoke of the
connecting rod 20 'a, the pawl 21 rides over the ratchet without
imparting motion to the table.
In order to permit the material in a mould to be given a further
pressing whilst the mould remains in the same position, the pawl 21 is
brought out of engagement with the catch wheel 20 by means of a
single-acting air cylinder 23 which is pivotally mounted on a pin 24
provided on a bracket 25 secured to the table turning catch plates The
free end of the piston rod 26 of the cylinder 23 is pivotally secured
to one end of a pawl lever 27, the pawl lever 27 being rigidly secured
at its other end, and advantageously over the greater part of its
length, to the catch pawl 21 The passage of compressed air into the
cylinder 23 is effective to swivel the pawl 21 on its pivot to
disengage it from the catch wheel 20, thus preventing the press-table
from being turhned on a forward stroke of the connecting rod 20 a.
Wheu the compressed air is released from the cylinder 23, the spring
22 is effective to bring the pawl 21 into engagement with the catch
wheel 20 so permitting the press-table to be turned; this movement

also returns the piston of the cylinder 23 to its original position
The compressed air passes into and out of the cylinder 23 through a
line 28, the flow of air being controlled by a valve actuated by the
cam mechanism.
The cam mechanism for synchronising and interlocking the alteration in
the effective length of the plunger strokes, by movement of the taper
plate 4, and the rotation of the press-table with the reciprocation of
the pressing foot 1, comprises a cam drum 30 (Figures 6, 7 and 8)
mounted on a rotary shaft, 31 which is provided with a chain wheel 32
driven from the main crankshaft of the press.
The cam drum 30 is provided with three similar circumferential
projections 33 at right angles to its axis, the outermost peri 70
pheral surface of each projection 33 being cylindrical in form The
three projections are spaced apart at equal intervals to provide two
grooves between the projections 33 and a space between 75 each of two
outer projections and the ends of the drum, the two spaces ahd the two
grooves being substantially 6 f equal width The spaces and the grooves
are both identified hereinafter as 80 grooves 34.
The cam surfaces are provided as the flanges 3-5 of arcuate 'segments
36, each segment 36 being substantially of L-shape in cross-section
The lower arm of each 85 segment 36 is adapted to seat in one of the
grooves 34 on the drum '301 with the upright arm of the segment
resting against the side-wall of one of the projections 33 and the
flange 3 5 resting on the 90 outer circumferential surface of the
projection The width of each flange 35 is preferably a little less
than half the width of each circumferential projectiob 33.
Each segment 36 is secured to the cam 95 drum 30 ' by one or more
screws passing through the lower arm of the segment and engaging in
tapped holes provided in the grooves 34 in the surface of the drum In
order that the position of a segment 36 100 may be readily adjusted
angularly on the surface of the drum, the lower arm of each segment 36
is provided with a slot or slots 37 through which the screw or screws
pass.
The ends of the flanges 35 are advan 105 tageously cut away at an
angle or bevelled in order that a cam follower may ride smoothly onto
and off the cam surface from and onto the circumferential projection
33 110 Each cam surface is advantageously formed by the flanges 35 of
two segments 36, the two segments being seated in adjacent grooves 34
with the flanges 35 bearing on the same circumferential pro 115
jection 33 of the cam drum 30 The length of each cam surface is thus
readily adjustable by movement of one or of both of the segments 36,
the maximum length of the cam surface being the sum of the lengths 120
of the arcs of the flanges 35 and the minimum length of the cam
surface being the length of the arc of one flange 35 or, where the

segments are of different arcuate length, being the length of the arc
of the 125 shortest flange or segment.
Thus three cam surfaces are provided on the circumferential
projections 33 of the cam drum 30 A cam follower in the form of a
roller 38 is provided for each 130 cam surface, eacl 'roller being
mounted on a rocker arm 39, the three rocker arms 39 and the cam drum
30 being advantageously enclosed within a casing 40 On one side wall
or walls of the casing 4 Q, three similar air valves 41 a, 41 b, 41 c,
are mounted so that each valve is opened in such manner as to permit
compressed air to pass into one of the two air cylinders 9 and 23,
when the cam follower 38 of its corresponding rocker arm -39 rides
over the corresponding cam surface or flange and is closed: when the
cam follower rides over and in contact with the corresponding
circumferential projection 33 on the cam drum 30 on which the cam
surface or flange 35 rests.
Each cam follower 38 is urged into contact with one 6 f the
circumferential projections 33 of the cam drum 30 by means of a spring
42 mounted on a hollow valve rod 49, which valve rod 43 bears at one
end against the rocker arm 39 on which the cam follower 38 is mounted
and which 25: extends through a side wall of the casing enclosing -the
cam drum 30 and into one of the three air valves Each of the air
valves 41 a, 41 b, 41 c, is normally kept closed by an internal spring
44 which urges the valve head 45 on to its seating 46, but the valve
is opened, whien the cam follower 38 rides over its cam surface or
flange:35,: by movement O of the hollow : valve rod 43 inwardly into
the valve to lift the valve-head 45 from its seating 46.
W: hen the cam follower 38 rides off the flange 35 o N to its
corresponding circumferential projections 33, the spring-pressed
hollow valve rod 43 moves outwardly of the valve and, out of
engagement with the valve-lihead 45; compressed air cannot then pass
into the cylinder 9 or 23 fed -by that partieutilar valve.
Each of the three air valves is provided with two ports, one port 47
of each valve being connected through a line 48 to a source of
compressed air Tlhe other ports 49 of the two valves 41 b, 41 c, are
connected to the double-acting air cylinder 9 which effects movement
of the taper plate 4, the valve 41 b, being connected through the line
15: to the trunnion end of the cylinder-9 and the valve 41 G, being
connected throu Lgh the line 16 to the other' end of cylinder 9 The
port 49 of the third valve 41 a is connected through the line 28 to
the single-acting air cylinder 23 which controls the rotation of the
press-table.
In the position of the cam drum 30 illustrated in l Figures 6, 7 and
8, the valve 41 a is open and compressed air is passing from the line
48 through the valve 41 a, port 49 and the line 28 into the

singleacting air cylinder 23 to disengage the pawl 21 from the catch
wheel 20 The valve heads 45 of the valves 41 b and 41 o are on their
seatings 46 aned the doubleacting air cylinder 9 is therefore not in
communication with the source of compressed air Any compressed air
present 70 in-the cylinder 9 can, however, escape {rom the cylinder,
and the route for the escape of the air may be described with
reference to valve 41 c as shown on Figure 7 Any compressed air
present in the 75 cylinder 9 under the lower face of its piston, is in
communication with the valve 41 c through the line 16 and the port 49.
l The inner end-of the hollow valve rod 43 is clear of the valve head
45 of the valve 80 41 o, and the compressed air from the cylinder 9
passes around the inner end of the valve rod 43, through its bore and
out into the ceasing 40 through one or more transverse holes 50 t
provided in the wall 85 of the valve-rod 43 One-or more vent holes 51
are provided in the cover andlor walls of the cam casing 40, through
which the compressed air from the cylinder 9 and 23 escapes to the
atmosphere Compressed 90 air is released from the trunnion end of the
cylinder 9 in similar mnianner through the valve 41 b, whilst the
compressed air is similarly released from the cylinder 23 through-the
air valve 41 a; 95 The cam drum 30 is geared to the main crankshaft of
the press to rotate at half the speed of the main crankshaft to give
two pressings to the material in each of the n oulds for each rotation
of the cam 100 drum In the apparatus illustrated in the drawing the
two cam surfaces 35 corresponding to the two air valves 41 b and 41 c
which are connected to the double-acting cylinder 9, each extend over
an arc of 105 about 167 and they are symmetrically spaced on the
surface of the cam drum 30 their ends being separated by an angle of
about 13 The cam surface 35 which controls the valve 41 a of the
single-acting 110 cylinder 23 extends over an arc of about 1,03 and
overlaps the two cam surfaces of the valves 41 b and 41 c which
control the cylinder 9, the overlap over the rear end of the cam
surface which serves to 115 withdraw the taper plates 4 being about '
and the overlap over the-front end of the cam surface which serves to
move the taper plate 4 inwardly over the fixed taper plate 3 being
about 25 120 The operation of the air valves in relation to one
another and to the two pressings given to the material in the moulds,
is shown in Figure 9 the cycles L, M, and X being those of the valves
41 c, 41 b 125 and 41 respectively for one revolution of the cam drum
30 The shaded parts of Figure 9 ' indicate the relative periods during
-which the three valves are held fully open to the source-of
compressed air, 130 785,017 while the unshaded parts indicate the
relative periods during which the valves are closed to the source of
compressed air except for the short periods when the valves are being
opened or closed as their cam followers 38 ride on or oft their

respective cam surfaces 35 Thus moveme t of the taper plate 4 between
its position of minimum overlap and its position of maximum overlap
(determined by one of the limits stops 17 e) relative to the plate 8,
takes place during the intervals X and Y.
Thus once in every revolution of the cam drum 30, the air valve 41 a
connected to the cylinder 28 is opened and compressed air passes into
the cylinder 23 The catch pawl 21 connected to the cylinder 23, is
thereby disengaged from the catch wheel 20 during the period indicated
by the shaded part of cycle N (Figure 9), and during this period
revolution of the main crankshaft driving the connecting rod a, is
ineffective to rotate the table of moulds Rotation of the table
through a determined angle through connecting rod a and catch pawl 21
occurs ohence during the period indicated by the unshaded part of the
cyle N to bring a further mould or set of moulds into position for
pressing of the material contained therein, this rotation of the table
occurring once in every two revolutions of the main crankshaft.
The pressing foot 1, reciprocating in unison with the rotation of the
main crankshaft thus completes two to-and-fro movements for every
revolution of the cam drum 30 and the material in each mould receives
two pressings.
During part of one revolution of the cam drum 3 (), the valve 41 c is
opened to permit compressed air to pass through line 16 into the base
of the double acting air cylinder 9 to cause its piston to travel in
one direction to move the taper plate 4 inwardly over the fixed taper
plate 3 to the extent permitted by the particular limit stop y 7 e,
and during another part of the revolution of the cam drum the valve 41
h is opened to permit compressed air to pass through line 15 into the
trunnion end of the cylinder 9 to cause its piston to travel in the
opposite direction to move the taper plate 4 outwardly over the fixed
taper plate 3 into the position of minimumi or no overlap Thus at each
reciprocation of the piston of the cylinder 9, the taper plate 4 will,
through the operating lever 6, be reciprocated over the taper face of
the fixed taper plate 3 When the two taper plates 3 and 4 are in the
position of minimum overlap, the material in a mould will be given its
first pressing.
and when the taper plates are ih the position of maximum overlap,
thus, in effect, increasing the stroke of the press-plunger, the
mnaterial will be given its second pressing I Tpon completion of the
second pressing of the material, compressed air passes through the
valve 41 b and the line 1 T 5 into 70 the trunnion end of the cylinder
9 to move the taper plate 4 back to its outermost position The two air
cylinders 9 and 23 are exhausted in the manner hereinbefore described
75 The air cylinder 23 has been described as a single-acting cylinder
It may, however, be provided as a double-acting air cylinder, in which

case a further circumferential projection, cam surface, cant 80
follower and air valve will be provided on the cam mechanism, and the
cylinder will also be connected to the supply of (ompressed air
through this further air valve.
The catch pawl 21 will then be returned 85 into position to engage the
next tooth of the catch wheel 20 under the positive action of the air
cylinder.
Thus in the apparatus particularly described, two pressings are
imparted to 90 the brick or briquettes material in the mould, the
pressure of one pressing being completely released before the next
pressing begins During the latter part of the outward travel of the
press hlumger or 95 phingcer: from a second pressings of the material
in one mould or set of moulds and during part of the inward travel of
the plunger or plungers for the first pressing of the material in a
further mould or set 100 of moulds, compressed air passes into the air
cylinder 9 at its trunnion end, to move the taper plate 4 into its
position of inimum overlap with respect to the fixed taper plate 3
During the return of the 105 plunger or plungers and during the early
part of the next inward stroke of the plungers, compressed air passes
into the air cylihder 9, at its piston rod end, on the other side of
its piston to bring the taper 110 Mlate 4 into its position of maximum
overlap with the second taper plate before the actual pressing begins
in the second pressing of the material The pressure in this second
pressing will then be greater than 115 the pressure in the first
pressing On the return stroke of the plunger, the air cylinder 9 is
actuated to withdraw the taper plate 4 from its position of maximum
overlap, so commencing a further 120 cycle in the movement of the
taper plate 4 for the first pressing of the material in a succeeding
set of moulds.
During the return movement of the plungers from a second pressing
rotation 125 of the press-table occurs to bring, the succeeding mould
or set of moulds into the pressing position.
It will be understood that the terms "minimum overlap " and "maximum
130 785,017 overlap " used in relation to the taper plates, are purely
relative, the degree of overlap being adjustable by varying the stroke
of the piston in the air cylinder 9 by means of the limit stops 17 of
the operating lever 6.
Furthermore, it will be evident that the brick or briquette material
in each mould may be given more than two pressings, the pressure of
each pressing being completely released before the next pressing
begins The pressure in each pressing may be varied as desired,
according to the nature or quality of the material being pressed, for
example, by advancing the first taper plate in two or more steps
between its position of minimum overlap and its position of maximum

overlap.
Thus, for example, each pressing may be effected under a higher
pressure than a preceding pressing, or each pressing may be of the
same intensity.
One or each air cylinder may be replaced by other means, for example,
a solenoid and its plunger, in such a case, the corresponding air
valve or valves will be replaced by a switch or switches and the
compressed air lines by an electrical circuit A valve rod may also be
replaced by a solenoid and core or plunger.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* 5.8.23.4; 93p

4606 4610.output

Recommended

Recommended

More Related Content

What's hot

What's hot (14)

Viewers also liked

Viewers also liked (14)

Similar to 4606 4610.output

Similar to 4606 4610.output (20)

More from j1075017

More from j1075017 (20)

Recently uploaded

Recently uploaded (20)

4606 4610.output