5276 5280.output

* GB785683 (A)
Description: GB785683 (A) ? 1957-11-06
Cyclopentanopolyhydrophenanthrene compounds
Description of GB785683 (A)
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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
7859683 Dte of Application and filing Complete Specification: Sept 16,
1953.
No 9553/56.
Application made in United States of America on Sept 17, 1952.
(Divided out of No 785,681).
Complete Specification Published: Nov 6, 1957.
Index at acceptance: -Class 2 ( 3), U 4 (A 1: A 2: Bi: C 3: C 5).
International Classification:-CO 7 c.
COMPLETE SPECIFICATION
Cyciopentanopolyhydrophenanthrene Compound's WC, MERCK & CO, INC, a
Corporation duly organised and existing under the laws of the State of
New jersey, United States of America, iof Rahway, New Jersey, 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 to
be performed, to be particularly described in land by the following
statement: -
This invention is concerned with novel
cyclopentanopolyhydrophenanthrene compounds and processes for
preparing them.
In brief, this invention provides novel
cyclopentanopolyhydrophenanthrene compounds having the formula:

c/IF a O /omi a in wich he 3 positio is ocuideihrb inywhich athree 3
potonmisocupids haing-therb formula FORMULA 3 in which the 3-position
is occupied by a univalent group which is convertible to keto by acid
hydrolysis.
lPrice 3 s 6 d l Examples of bivalent groups which may occupy the
3-position in the compounds of Formula a are cyclic ketal groups, eg.
ethylenedioxy, ethylene, dithioketal, and ethylene hemithioketal;
pairs of univalent groups which may occupy the 3-position in the
compounds of Formula a include noncyclic ketals such as dimnethyl
ketal; single univalent groups which may occupy the 3position in the
compounds of Formula b include enol ethers such as eithyl enol ether.
The preferred group is the ethylenedioxy group which gives a compound
of Formula a in which the 3-position has a N-.
substituent.
In the subsequent description for convenience and to avoid repetition,
reference will be made to the 3-ethylenedioxy compounds of the 45
invention and to the 3 ethylenedioxy compounds from which they are
prepared It is to be understood, however, that the reactions described
for such compounds apply alsoi to the analogous compounds in which the
3-position 50 of the molecule is substituted in iany of the ways
mentioned above in connection with the definition of Formula a and b,
so, that the compounds in question may have one or two nuclear double
bonds, depending on how the 55 3-position is substituted, i e when the
3-substituent is a ketal or cyclic ketal, the compound will be ia
A'-ene and when it ( 18 an ienol ether, the compound will be a A 1
',dieme 60 The function of this 3-substituent is to pro Ltect thec
3-keto group from reactions such as oxidation and addition, and the
manner of its introduction into the 7-position of 4 b-methyl-
1,4-dihydroxy-7 keto 1,2,3,4,4 a,,4 b,5,6,7, 65 9,10,10
a-dodecahydrophenanthrene forms part of the invention claimed in our
coptending Application No 29358/55 (Serial No.
763,208).
The novel compounds of the invention are 70 useful as starting
materials in the process described and claimed in the specification of
our copending Application No 9554/56 (Serial No 785,684).
In accordance with the invention, the novel 3-ethylenedioxy compounds
are prepared from A 5-3-ethylenedioxy-1 l keto-etienoylpyruvic acids
compounds of formula:
C/I 2 co cooa Co which compounds form the subject of our copending
Application No 25642/53 (Serial No 785,681).
The etienoylpyruvic acid compound is converted to the corresponding
21-iodo compound by reaction with iodine This reaction is most
conveniently carried out by intimately contacting an aqueous solution
of A 5-3-ethylenedioxy-ll-ekto-etienoylpyruvic acid, buffered with an

agent such as disodium phosphate, with iodine The preparation of the
21-iodo compound is completed by allowing the reaction mixture to
stand at room temperature for about 10-20 hours After the reaction is
complete, the resulting mixture is extracted with a water-immiscible
solvent such as ether.
When the ethereal extract is evaporated, the desired iodo compound is
obtained It is desirable in carrying out the preparation of the iodo
compound to protect the reaction mixture and the formed iodo compound
from light in 'order to avoid decomposition of this product.
The process of the invention is illustrated by the following example.
EXAMPLE.
To a solution of 1 804 g lof
d-A'-3-ethylenedioxy-11-keto-etienoylpyruvic acid in 450 cc.
of water containing 20 g of disodium phosphate was slowly added with
stirring a suspension of 1 05 g of iodine in 100 cc of ether.
After the iodine colour had disappeared, a solution of 1 g of
potassium hydroxide in 30 cc of water was added and the mixture
protected from light and stirred for 20 hours.
The ethereal layer was then separated, dried, and evaporated in vacao
to give crude crystalline d-Az-3-ethylenedioxy-11,20-diketo
-21hlodo-pregnene.
The procedure was repeated using as startS ing material
dl-A'-3-ethylenedioxy ll-ketoetienoylpyruvic acid to obtain the
dt-21-iodocompound.
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* 5.8.23.4; 93p
* GB785684 (A)
Description: GB785684 (A) ? 1957-11-06
Cyclopentanopolyhydrophenanthrene compounds

No 7859684 F o x Date of Application and filing Complete
Specification: Sept 16, 1953.
N.9554156.
R 2 S / Complete Specification Published: Nov 6, 1957.
Index at acceptance:-Class 2 ( 3), U 4 (A 1: A 2: B 1: C 4: C 5).
Cyclopentanopolyhydrophenanthrene Compoundsl We, MERCK & Co, INC, a
corporation duly organised and existing under the laws of the State of
New Jersey, United States of America, of Rahway, New Jersey, 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 to
be performed, to be particularly described in and by the following
statement:-
cyclopentanopolyhydrophenanthrene compounds and processes for
preparing them.
In brief this invention provides d I-11dehydrocorticosterone and
processes for preparing this compound and its stereoisomers, in
particular d-1 l-dehydrecorticosterone (Kendall's Compound A), al
naturally occurring hormone of the adrenal cortex The invention also
provides novel cyclopentanopolyhydrophenanthrene compounds having the
formula:
CEOR f ORA 9 ULA a Z in which the 3-position, is occupied clther by a
bivalent group convertible to keto by acid hydrolysis or by a pair of
univalent groups together convertible to a single keto group by acid
hydrolysis; and novel cyclopentanopolyhydrophenanthrene compounds
having the formula:
C#OR lPiice 3 s Co POBM>Uh A 5 (Price 3 s 6 d l 1 in which the
3-position is occupied by a univalent group which is convertible to,
keto by acid hydrolysis In the foregoing Formula a and b, R represents

a hydrogen atom or an acyl group.
Examples of bivalent groups which may occupy the 3-position in the
compounds of Formula a are cyclic ketal groups, e g ethylenedioxy,
ethylene dithioketal, and ethylene hemithioketal; pairs of univalent
groups which may occupy the 3-position in the compounds of Formula a
include non-cyclic ketals such as dimethyl ketal; single univalent
groups which may occupy the 3-position in the compounds of Formula b
include enol ethers such as ethyl enol ether The preferred group is
the ethylenedioxy group, which gives a compound of Formula b in which
the 3-position has a 6 ubstituent.
In the subsequent description for convenience and to avoid repetition,
reference will be made to the A
5-3-ethylenedioxy-cyclopentanopolyhydrophenanthrene compounds It is to
be understood, however, that the reactions described for such
compounds apply also to the analogous compounds in which the
3-position of the molecule is substituted in any of the ways mentioned
above in connection with the definition of Formula a and b, so that
the compounds in question may have one or two nuclear double bonds,
depending on how the 3-position is substituted, i e when the
3-substituent is a ketal or cyclic ketal, the compound will be a 4
A'-ene and when it is an enol ether, the compound will be a A 3 "
-diene.
The function of this 3-substituenu is to protect the 3-keto group from
reactions such as oxidation and addition, and the manner of its
introduction into the 7-position of 4 b-methyl-
1,4-dihydroxy 7 keto-1,2,3,4,4 a,4 b,5,6,7,9, 2 785,684 10,10
a-dodecahydrophenanthrene forms part of the invention claimed in our
copending Application No 29358/55 (Serial No.
763,208) The 21-hydroxy 3-protected compounds may, in accordance with
the invention, be hydrolysed by acid to, the corresponding A
4-3-keto-compound having the formula:
F:ORJIA C The novel 21-acyloxy 3-ethylenedioxy compounds are prepared
from the steroid compounds of formula CO oko which fonn the subject of
our copending Application No 9553/56 (Serial No 785,683), by reacting
them with an alkali-metal salt of a lower aliphatic acid This reaction
is conveniently carried out by heating a solution of the iodo compound
dissolved in acetone under refiux with potassium acetate for about one
hour After completion of the reaction, the product is readily
recovered by evaporating the acetone under diminished pressure,
extracting the resulting residue with ether and evaporating the
ethereal extract.
The z-'-3-ethylenedioxy-11,20-diketo-21acyloxy-pregnene so obtained is
readily hydrolysed to obtain 11-dehydrocorticosterone The 21-acyl
substituent is conveniently removed by hydrolysis with an alkali and

the 3-ethylenedioxy substituent can then be hydrolysed by treatment,
with acid to form ll-dehydrecorticosterone.
In carrying out the processes described above, the starting material
may be either dA 5-3-ethylenedioxy-11,20-diketo, 21 iodopregnene, or
the corresponding dl compound.
When the d-isomeric form is used as the start ing material, the
product obtained is identical with naturally occurring
ll-dehydrocorticosterone When the racemic mixture is used as the
starting material, a racemic mixture of the d and 1 forms of
11-dehydrocorticosterone is obtained.
The following example illustrates the process of the invention.
EXAMPLE.
The crude crystalline)'-3-ethylenedioxy11,20-diketo-21-iodo-pregnene,
obtained from d-A'-3-ethylenedioxy 11 keto etienoylpyruvic acid as
described in the Example of our copending Specification No 9553/56
(Serial Nc' 7835,683), was dissolved in 70 ccs.
of acetone and refluxed for 1 hour with 6 g.
of potassium acetate The acetate was then evaporated it vacuo, the
product was extracted with ether, and the ethereal solution was washed
with water, dried, and evaporated.
The crystalline residue was purified by chromatography on alumina
Elution with a mixture of petroleum ether and ether gave
dA-3-ethyltnedioxy-11,20-diketo 21-acetoxypregnene, m p 1950 C.
Upon hydrolysing this compound with alkali, the 3-ethylenedioxy
derivative of 11dehydrocorticosterone was obtained The latter was
hydrolysed with acid to remove the 3ethylenedioxy group and there was
obtained ll-dehydrocorticosterone, identical with naturally occurring
ll-deihydrocorticosterone (Kendall's Compound A).
When dl-X 5-3 ethylenedioxy 11 ketoetienoylpyruvic acid was -weated by
the procedure of the Example of the said copending Specification No
9553/56 (Serial No.
785,683) and the resulting dl- A-3-ethylenedioxy 11,20 diketo -21
iodopregnene was treated in accordance with the procedure of the
Example of the present specification, the corresponding dl compounds
were obtained.
The dl-A'-3 ethylenedioxy-l 1,20-diketo21-acetoxy-pregnene was
chromatographed on alumina and eluted with a mixture of benzene and
ether and its m p found to be 190-192 C This -was hydrolysed with
alkali and then with acid to obtain dl-ll-dehydrocorticosterone.
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* 5.8.23.4; 93p
* GB785685 (A)
Description: GB785685 (A) ? 1957-11-06
Steroid compounds
7 Date of Application and filing Complete Specification: Sept 21,
1953.
N.9817/56.
"' Complete Specification Published: Nov6, 1957.
Index at acceptance:-Class 2 ( 3), U 3, U 4 (A 1: A 2: B 1: C 4: CX).
Steroid Compounds We, MERCK & CO, INC, a corporation duly organised
and existing under the laws of the State of New Jersey, United States
of America, of Rahway, New Jersey, 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 to be performed, to be
particularly described in and by the following statement:-
cyclopentanopolyhydrophenanthrene corm pounds and processes for
preparing them.

In brief, this invention provides novel
cyclopentanopolyhydrophenanthrene compounds having the formula:
acid hydrolysis In the foregoing Formulae a and b, R represents an
acyloxy group.
Examples of bivalent groups which may occupy the 3-position in the
compounds of Formula a are cyclic ketal groups, e g, ethylenedioxy,
ethylenedithioketal, and ethylene hemithiolketal; pairs of univalent
groups which may occupy the 3-position in the compounds of Formula a
include non-cyclic ketals such'as dimethyl ketal; single univalent
groups which may occupy the 3-position in the compounds of formula b
the ethylenedioxy group, which gives a compound of Formula a in which
the 3-position has a in which the 3-position is occupied either by a
bivalent group convertible to keto by acid hydrolysis or by a pair of
univalent groups together convertible to a single keto group by acid
hydrolysis.
The invention also provides novel cyclopentanopolyhydrophenanthrene
compounds having the formula:
PO/?MCILS A in which the 3-position is occupied by a
univalenrroupiwhich is convertible to keto by substituent In the
subsequent particular description, for convenience, and to avoid
repetition, reference will be made to the 3ethylenedioxy
cyclopentanopolyhydrophenanthrene compounds It is to be understood,
however, that the reactions described for such compounds apply also to
the analogous compounds in which the 3-position of the molecule has a
substituent of any of the types mentioned above in connection with the
definition of Formulae a and b, so that the compounds in question may
be A, 17 ( 2 O)_dienes or 3 A 5 ' 20 '-trienes, depending on how the
3position is substituted The function of this 3-substituent is to
protect the 3-keto group from reactions such as oxidation and
addition, and the manner of its introduction forms part of the
invention claimed in our copending Application No 29358/55 (Serial No.
763,208).
The novel compounds of the invention may readily be converted to
cortisone esters by the method described and claimed in the
specification of our copending Application No.
9818/56 (Serial No 785,686).
The novel 3-ethylenedioxy compounds are 85,685 50:
55.
2 785,685 prepared, in accordance with the invention, from the
corresponding A'-3-ethylenedioxy11 keto 20
hydroxy-20-cyano-21-acyloxypregnene of formula:
subject of our copending Application No.
25992/53 (Serial No 785,682), by reacting it with a dehydrating agent.

The reaction is most conveniently effected by reacting the starting
compound with phosphorus oxychloride in the presence of pyridine at,
room temperature for about 16 hours The l'7 '20 '-cyano compound is
recovered by diluting the reaction mixture with water and allowing the
reaction mixture to stand, whereupon the product precipitates in
crystalline form.
The process of the invention may be illustrated by the following
example.
EXAMPLE.
A solution of 135 mg of z '-3-ethylenedioxy 11 keto 20
hydroxy-20-cyano-21acetoxy pregnene in 0 7 cc of pyridine was treated
with 0 07 cc of phosphorus oxychloride After standing at room
temperature overnight, the reaction mixture was diluted with water
After standing, the aqueous mixture deposited crystals of 2 A 3 172 'I
-3-ethylenedioxy-11-keto-20-cyano 21 acetoxypregnadiene which after
recrystallization was found to melt at 2030 C.
When the above procedure was repeated using dl-A'-3-ethylenedioxy 11
keto-20hydroxy-20-cyano-21-acetoxypregnene as the starting material,
dl-" 5 17 ( 20 '-3-ethylenedioxy11-keto-20-cyano 21
acetoxy-pregnadiene melting at 181-183 C was obtained.
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* GB785686 (A)
Description: GB785686 (A) ? 1957-11-06
Steroid compounds

785,686 Date of Application and filing Complete Specification: Sept
21, 1953.
I; No 9818/56.
Index at acceptance:-Class 2 ( 3), U 4 (A 1: A 2: Bi: C 4: C 5).
Steroid Compounds We, MERCK & CO, INC, a corporation duly organised
and existing under the laws of the State of New Jersey, United States
of America, of Rahway, New Jersey, 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 to be performed, to be
particularly described in and by the following statement: -
This invention is concerned with steroid compounds and processes for
preparing them.
More particularly, but not exclusively, it is concerned With the novel
compound dl-cortisone acetate and certain of its derivatives.
In accordance with the invention there is provided a process for
obtaining compounds of the formula:
Co There are also formulae:
FORMIL A I provided compounds of the Po O MULA M' In the Formulae I,
II and III, R is an;acyloxy group In the compounds of Formula II, the
3-position is occupied either by a bivalent gnoup convertible to keto
by acid hydrolysis or by two univalent groups together convertible to
a single keto group by acid hydrolysis, and in the compounds of
Formula Il I, the 3-position is occupied by a univalent group
convertible to keto by hydrolysis.
Examples of bivallent groups which may occupy the 3-position in tthe
compounds of Formula II are cyclic ketal groups, e g ethylenedioxy,
ethylene dithijoketal, and ethylene heemithioketal; pairs of univalent
groups which may occupy the 3-position in the compounds of Formula II
include non-cyclic ketads such as dimethyl ketal; single univalent
groups which may occupy the 3-position in the compounds of Formula III
the ethylenedioxy group which gives a compound of Formula II in which

the 3-position has a thy > substituent.
In the subsequent particular description, for convenience and to avoid
repetition, reference will be made to the 3-ethylenedioxyFOR Wa Ul A
if and 2 785,686 dodecahydrophenanthrene compounds It is, however, to
be understood that reactions described later may be applied to
compounds in which the 3-position of the molecule is substituted in
any one of the ways mentioned above in connection with the definitions
of Formulae II and III, so that the compounds involved may be either
A'-pregnene or A"'-pregnadiene compounds, depending on how the
3-position is substituted.
The function of the 3-substituent is to protect the 3-keto group from
reactions such as oxidation and addition, and the manner of its
introduction forms part iof the invention claimed in our copending
Application No.
29358/55 (Serial No 763,208) Compounds blocked in the 3-position may,
in accordance with the invention, be converted to the 3keto compounds
with acid, a suitable reagent being paratoluenesulphonic acid There is
thereby obtained a poilyhydrophenanthrene having the Formula I set
forth hereinbefore.
These compounds are a,%-unsaturated ketones.
The novel 3-ethylenedioxy compounds of the invention may be prepared
from At'T 70-3-ethylenedioxy-11-keto-20 cyano21-acyloxypregnadienes,
which form part of the invention claimed in our copending Application
No 9817/56, (Serial No, 785,685), by treating them with an oxidizing
agent, preferably a permanganate salt such as a permanganate of an
alkali metal or alkalineearth metal For example, this reaction can be
readily carried out by intimately contacting a solution of A 517 '20
'-3-ethylenedioxy-11ketco-20-cyano-21 acetoxypregnadiene in acetone
with powdered potassium permanganate at a temperature of about O ' C
for about 90 minutes The reaction mixture is then decomposed by the
addition of a solution of sodium sulphite and dilute sulphuric acid
The desired product is recovered by extracting the acidified reaction
mixture with a waterimmiscible solvent for the product, such as
chloroform Upon evaporation of the solvent extracts A
5-3-ethylenedioxy-11,20-diketo 17hydroxy-2-acetoxypregnene is obtained
in crystalline form.
The protecting ethylenedioxy substituent may then be removed by
hydrolysis with acid to regenerate the 3-keto substituent and cause a
shifting of the double bond from the 5,6 position to the 4,5 position,
thereby forming cortisone acetate Thus, the hydrolysis is conveniently
effected by heating a suspension of A 5-3-ethylenedioxy-11,20
diketo17-hydroxy-21-acetoxypregnene in acetone with p-toluenesulphonic
acid, when an exchange ketaflization takes place and the ethylenedioxy
group is transferred from the 3-position of the steroid compound to

the acetone molecule The cortisone ester is obtained by diluting the
reaction mixture with water whereupon the product is obtained in
-crystalline form.
The above described reactions can also be carried out using dl-A
5-3-ethylenedioxy-11,20diketo-21-acetoxy-pregnene to obtain the
racemic cortisone ester, dl-cortisone acetate.
The following examples illustrate methods of carrying out the
invention.
EXAMPLE 1.
A'-3-Ethylenedioxy-11,20-diketo-17hydroxy-21-acetoxypregnene.
A solution of 102 mg of A 5 17 " 20)-3-ethylenedioxy-11-keto-20 cyano
21 acetoxypregnadiene in 3 5 cc of acetone containing 0.11 cc of
piperidine was cooled to O O C.
and treated with 94 mg of powdered potassium permanganate After
stirring the mixture for 90 minutes at 00 C, 0 2 cc of acetone
containing 0 02 cc of acetic acid was added.
The mixture was stirred for an additional 90 minutes at room
temperature and then decomposed with a solution of sodium bisulphite
and dilute sulphuric acid The mixture was extracted with chloroform
and the chlorofoekm extract was washed with water, stirred with a 5 %
aqueous solution of potassium carbonate, and concentrated in vacao to
remove the chloroform The resulting crystalline suspension was
filtered and washed with water and methanol, giving A
2-3-ethyleredioxy-i 1, 20-diketo-17 o-hydroxy-21 acetoxypregnene.
Recrystallization from pyridine methanol gave pure material, m p
262-267 C with decomposition.
When the above described procedure was repeated using dl-5172 '0
'-3-ethylenedioxyll-keto-20-cyano-21-acetoxypregnene as the starting
material
di-A'-3-ethylenedioxy-11,20diketo-17-hydroxy-21-acetoxypregnene
melting at 247-252 C was obtained.
EXAMPLE 2.
Cortisone Acetate 105 A suspension of 50 mg of 3-ethylenedioxyZ
5-pregnene-17 %,21-diol 11,20 dione 2 iacetate in 3 cc of acetone
containing 15 mg.
of p-toluene-sulphonic acid was refluxed for minutes Dilution with
water gave crystal 110 line cortisone acetate, m p 238-244 C.
When the above-described procedure was repeated using
di-A'5-3-ethylenedioxy 11,20diketo-17 a-hydroxy-21-acetoxypregnenc as
the starting material, dl-cortisone acetate melting 115 at 240-245 ' C
was obtained.
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* GB785687 (A)
Description: GB785687 (A) ? 1957-11-06
Improvements in or relating to devices for sensing the magnitude of
deviation of operating conditions of an engine
785,687 d, I -Date of Application and filing Complete k
Specification: March 15, 1954 No 747
Application made in United States of America on April 10, 1953.
Index at acceptance:-Class 40 ( 1), N 1 A( 2:3 B), N 3 ( 57 E:87
F:VSP).
International Classification:-008 c.
Inprovements in or relating to Devices for Sensing the Magnitude of
Deviation of Operating Conditions of an Engine r 9154 o We, BENDIX
AVIATION CORPORATION, of 401 North Bendix Drive, South Bend, Indiana,
United States of America, a Corporation organized under the laws of
the State of Delaware, 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 to be performed, to be particularly
described in and by the following statement
This invention relates to devices for sensing the magnitude of
deviations of an operating condition of an engine, such as the
rotational speed of the latter and to compare the same with a
reference value, and more particularly to electrical sensing devices
of the above type.
In the past attempts have been made to use, as a speed sensing means,
a direct current tachometer which produces a direct current voltage

varying in magnitude with the speed of rotation It has been found,
however, that sensing speed on this basis is subject to considerably
more error than is acceptable for highly critical applications such as
fuel control devices for gas turbine engines.
According therefore to a first aspect of the present invention, there
is provided a device for sensing the magnitude of deviation of an
operating condition of an internal combustion engine from a reference
value, comprising electrical means for producing an alternating
current having a frequency proportional to said operating condition
and electron tube counter means for translating said alternating
current into a direct electrical voltage varying in magnitude with
changes in said operating condition, and cooperating with means to
compare said voltage with a direct reference voltage for creating an
error signal.
According to another aspect of the lPrice 3161 invention, there is
provided a device for sensing the magnitude of deviation of the
rotational speed of an engine from a predetermined value comprising
electrical means including electron tube counter 50 means operable to
produce a direct electrical voltage varying in magnitude with the
frequency of an alternating current, said frequency being proportional
to said rotational speed, and co-operating means 55 to compare said
direct voltage with a direct reference voltage for creating an error
signal.
A signal anticipating changes in rotational speed can be used in the
device 60 thus improving system stability and providing a speed error
signal which is highly accurate in reflecting variations from a
selected speed.
In order that the invention may be more 65 clearly understood, the
invention will now lie described by way of example with reference to
the accompanying drawings in which:Fig 1 is a block diagram of a speed
70 sensing device and control mechanism used in conjunction with a gas
turbine engine and incorporating the present invention, Fig 2 is a
schematic wiring diagram of the speed sensing device 75 With reference
to Fig 1, numeral 10 designates a control device containing a fuel
metering valve which controls the fuel passing from a source (not
shown) to a manifold 12, of a gas turbine engine 80 14 An alternating
current tachometer 16 is connected to the turbine in such manner that
the rotational speed of the tachometer is directly proportional to
that of the turbine A signal from the tacho 85 meter feeds into the
speed sensing device 18 which compares this signal with a reference
signal established by the throttle The speed sensing device then
supplies a signal representative of varia 90 a 4, a 785,687 tions from
the reference to 'he controller 22, which is a device for coordinating
and amplifying several control signals in such manner that a resultant

signal may be utilized by a mnetering valve actuator 24 This valve
actuator may consist of a reversible two-phase electric motor having
an exciting winding and a control winding.
In Fig 2 the tachometer 16 which is directly connected to turbine 14,
generates an alternating voltage across resistor 30, the frequency of
which is directly proportional to the rotational speed of the turbine
This alternating current signal is impressed upon grid 32 of triode
34.
which is one-half of a vacuum tube containing two triodes, and an
amplification takes place Because triode 34 is driven alternately
between saturation and cutoff, a squared and limited sine wave appears
at anode 36 Grid 32 is protected from drawing excessive current during
the positive half cycle by grid limiting resistor 38.
The amplified signal appearing on anode 36 is coupled to grid 40 of
triode 42 through condenser 44 The action of grid limiting resistor 45
corresponds to that of resistor 38 At plate 46 of triode 42 appears a
voltage of a square lwave form varying in frequency with turbine speed
Numerals 4 '-3 and 47 represent standard anode resistors.
Condenser 48 and resistor 50 comprise a differentiating network across
which the square wave signal from plate 46 is converted to alternating
positive and negative pulsations of short duration.
These pulsations are coupled to grid 52 of thyratron tube 54 by grid
limiting resistor 56 The action of the tube 54, which can be
considered a counter tube is as follows: Just prior to the arrival of
a positive pulse on grid 52, the tube 54 is held cut-off by the
negative grid voltage from the power supply Condenser 38 is charged to
the anode power supply potential or B plus voltage and no current is
flowing through either resistance 60 or resistance 62 When the
positive pulse appears on the grid 52, the negative grid bias is
overcome and the tube 54 ionizes, causing condenser 58 to discharge
rapidly through tube 54 and resistor 60 The action of condenser 58
prevents the rapid decay of cathode voltage and thereb-y allows the
grid to regain control of the tube Condenser 58 then charges throuo'h
resistor 62 to the polver supply potential and the tube is once again
in a quiescent state ready to accept the next positive pulse The
funetion of resistor 61 and capacitor 63 is to keep transient signals
from the counter eircuit from feeding back to triodes '34 and 42.
The average current through resistor 62 is directly proportional to
the capacity of condenser 58, the power supply voltage, and the
frequency of the firing pulses 70 Since E=IPR, then the average
voltage across resistor 62 is a function of the frequency and the
power supply voltae -when resistance 62 and capacitance 58 are held
constant With all circuit values 75 except the frequency of
pulsationls ac ross tube 3 held constant, the average voltage across

resistor 62 becomes dependent upii the frequency of pulsations alone
anld hence, upon the rotational speed of the 80 turbine 14 Inductance
wiindins 66 ( and 68 and condensers 64 and 70 constitute all average
filter, and across condenser 70 appears an average voltage
proportional to turbine speed 85 Resistors 72 and 74 and condenser 76
comprise an output dilrerelitiatiin', - r phase lead network such that
the o Litput across resistor 7-4 contains a voltage in linear
relationship with turbine speed ando 90 ill linear relationship with
the 1st derivative or rate of change of speed.
Resistor 78 and potentiometer S) comprise a voltage dividing netwurk
from ilee anode supply voltage to ground in wlm-hi 95 slider 82
actuated by throttle 20 picks off a reference signal The two signals,
one from the potentiometer 50 and one across resistor 74 are then
applied to the contacts of modulator or chopper 84 This 100 modulator
then alternately compares the two outputs, one a signal in linear
relatiotnship with actual engwine speed and to rate of change of speed
respectively, and the other a reference signal as established by 105
the throttle The resulting pulsating direct current voltage appearing
across resistor 86 is a speed error signal reflecting the magnitude
and direction of the difference in turbine speed from that set 110 on
the throttle 20 This error signal is then fed to the controller which
utilizes it and other signals to establish the desired turbine speed.
It will be noted by reference to Fig 2 115 that potentiometer SO is
fed through resistor 78 from the same power source as that whiell
supplies the anode eire'nt of the counter, thvratron tube 54 Since
counter output is proportional to its 120 applied anode voltage, a
change in anode voltage will be reflected both across resistor 74 and
potentiometer 80 Because these two signals are c omlpared tbrouih
modulator 84 it follows that the system 125 is self'-eompensatiiig for
chanlges in linle voltage.
Operation of ou 1 r speed sensiir dew is as follows: Assuming a
conditiolln wserue the engine is operating at the speed 130 785,687
established by the throttle setting, the signal from the counter
developed across resistor 74 will be equal to that from potentiometer
80 These signals will cancel and no voltage will be developed across
resistor 86 Hence, there will be no speed signal to the controller Now
assume the pilot moves the throttle in a direction corresponding to a
request for increased 1.0 speed The voltage from potentiometer 80 will
increase, thus developing a pulsating direct current voltage across
resistor 86.
This signal is used bv the controller to open the fuel valve, which
causes the engine to increase speed This change is reflected by the
tachoineter, which increases the frequency of its signal to the grid
of triode 34 This signal is amplified through triodes 34 and 42,

converted into unidirectional pulsations of the tachometer frequency
by counter tube 54 and is subsequently filtered This filtered signal
appears across resistor 74 as a smooth direct voltage of magnitude
propor Itional to tachometer frequency The function of condenser 76 is
to reflect changes in the direct current by means of a phase shifting
action which tends to anticipate the changes Because of this action,
the rate of speed increase falls off as the requested speed is
approached thus providing a damping action.
Conversely, if either through a request from the pilot or through
changes in external conditions, the engine is rotating faster than the
signal from the throttle demands, a pulsating direct current will be
developed across resistor 86 in a direction opposite to that
established in the example above The controller will utilize this
signal to rotate the fuel valve in a closing direction, causing engine
speed and hence, tachometer output frequency, to decrease This change
will be reflected through the amplifier and counter as outlined above.
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