1. * GB780085 (A)
Description: GB780085 (A) ? 1957-07-31
Improvements in or relating to electrical heating devices
Description of GB780085 (A)
PATENT SPECIFICATION
780085 Date of filing Complete Specification: July 29, 1955.
Application Date: Dec. 3, 1954. No. 35082/54.
Complete Specification Published: July 31, 1957.
Index at acceptance:-Class 39(3), H(1J2: 1X: 2E4C).
International Classification:-HO5b.
COMPLETE SPECIFICATION
Improvements in or relating to Electrical Heating Devices I, HENRY
HERBERT GOLDSTAUB, A.M.I.E.E., a British subject, of 61 Mount Pleasant
Road, Chigwell, Essex, do hereby declare the invention, for which I
pray that a patent may be granted to me, and the method by which it is
to be performed, to be particularly described in and by the following
statement:-
This invention relates to electrical heating devices and is concerned
with a device which can be used in a laboratory for heating test
tubes, small flasks and beakers, crucibles, and for welding
polyethylene-ware. When the device is inverted it can also be used to
provide the heat source for evaporation processes.
According to the present invention there is provided an electrical
heating device, comprising a main casing having an opening at one end,
a base member upon which the device can stand associated with the
other end of the casing, a secondary casing within said main casing
and located near said one end thereof, there being a space between the
walls of the main casing and the walls of the secondary casing, said
secondary casing having an open end adjacent said one end of said main
casing, an openended hollow refractory member for reception of
material to be heated, which member is supported within said secondary
casing in such manner that the open end of said member is directed
towards said open end of said secondary casing, and electrical
resistance wiring embedded within said refractory member for heating

2. the latter, the construction being such that the device can be stood
on its base with the open end of the refractory member upwardly
directed.
For a better understanding of the invention and to show how the same
may be carried into effect, reference will now be made to the
accompanying drawings in which:Fig. 1 shows a cross-section of a
heating device, Fig. 2 shows an outside view of the heating device
shown in Fig. 1, and Fig. 3 shows a cross-section of a modified
heating device of the kind shown in Fig. 1.
Referring now to the drawings, in which analogous parts have the same
references, a heating device includes a cylindrical main casing 1 open
at both ends. To one end of the casing is secured a base 2 which
includes a shortskirt-like member 3, the sides of which are outwardly
flared. Within the bottom of the skirt-like member is secured a flat
disc 4 from the underside of which protrude three spaced rubber feet
5, so that the device may be stood on a bench without undue conduction
of heat from the device to the bench. The periphery of the lower half
of the main casing has several rows of slots 6 therein, the rows lying
one above the other and each row including a number of slots spaced
around the circumference of the casing, the slots in one row being
staggered in relation to the slots in an adjacent row. A secondary
casing 7 open at its upper end, is supported within the upper half of
the main casing, this secondary casing carrying a refractory member 8
which may be made of aluminium oxide. The secondary casing is of
smaller diameter than the main casing so that there is an annular
space there-between.
The refractory member is a hollow cone in form, save that the apex of
the cone is rounded.
The refractory member is supported with the secondary casing with the
apex on the base 9 of the secondary casing and with the hollow in the
refractory member directed upwardly.
The space between the refractory member and the secondary casing is
filled with a packing 10 such as asbestos wool and the refractory
member terminates at the level of the open end of the main casing. A
winding of electric resistance wire is embedded within the refractory
member, the leads 11 from this resistance wire passing through the
base of the secondary casing and out through the base member
associated with the main casing. An annular cowl 12 with outwardly
flared sides is secured over the open end at the top of the main
casing, an aperture 13 in the cowl being slightly larger in diameter
than the open end of the refractory member.
In Fig. 3 a perforate baffle plate 14 is shown located between the
base 9 of the secondary casing and the base 2 of the main casing. The
perforate baffle plate is louvered by having tongues 15 which project

3. away from the plate 14 towards the base 2, each tongue being formed
directly from the plate by cutting on three sides and bending. The
effect of the baffle plate is to reflect heat back towards the base 9
of the secondary casing and to prevent the circulation of hot air to
the lower part of the main casing.
The baffle plate 14 is supported by brackets 16 and 17 located on the
base of the secondary casing and the side of the main casing
respectively, holes being provided in the baffle plate for passing
through the leads 11.
In the use of the device described above, when the resistance wire
associated with the refractory member is energised, the refractory
member is very quickly heated and, because of the shape of the
refractory member, radiant heat tends to be concentrated towards the
centre of the top of its hollow, i.e. the position the lower part of a
test tube might occupy when the heating device is in use. The cowl
over the open end of the main casing assists in deflecting hot air
away from the hand of a user of the device. Air can circulate through
the slots in the lower part of the main casing, through the annular
space between the secondary casing and the main casing and out through
the open end of the main casing, so preventing any undue temperature
rise of the casing and assisting the transference of heat in an upward
direction.
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