Improvements in Apparatus for Imparting a Predetermined Temperature to Liquids for Use in Developing Photo- graphic Plates, and for other purposes.
Year: 1894

page_text: Date of Application, 14th Nov., 1894
Complete Specification Left, 12th Aug., 1895-Accepted, 29th Sept., 1895
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Imparting a Predetermined
Temperature to Liquids for Use in Developing Photo-
graphic Plates, and for other purposes.
I CHARLES EDWARD HEARSON of No. 5 Templar Street Camberwell in the
County of Surrey Engineer do hereby declare the nature of this invention to be
as follows:-
In developing photographic plates it is important that the developing liquid be
brought to a standard temperature immediately before use and it is also important
that the water used for warming the developing dish be also brought to the same
temperature. To provide means whereby the said liquids may be readily brought
to the standard temperature when they are about to be used is the object of my
invention which consists of the improvements hereinafter described in apparatus for
imparting a predetermined temperature to liquids for the said purpose and for
other purposes.
According to my said invention I support a vessel for containing water above a
gas burner surrounded with a light proof shield having inlets and outlets for air
and I mount within the said vessel a thermostat which I so connect to a valve
governing the supply of gas to the burner that gas is allowed to pass thereto or is
shut off therefrom automatically according as the temperature of the water in the
said vessel is below or above a predetermined degree at which the thermostat will
act. I prefer to provide the thermostat with means for adjustment in order that it
may be caused to act at any desired temperature within a given range and I provide
for constant burning of a small jet of gas at the burner by means of a by-pass the
passage of gas through which is uncontrolled by the thermostat. Within the said
vessel I form passages which may consist of coils of tubing.one of which passages
is connected with a supply of water and the other with a funnel to admit of ready
insertion of the developing liquid and each of the said,passages is provided with an
outlet pipe from which the liquids which become warmed while flowing through the
said passages are received as required.
The kind of thermostat which I prefer consists of a hermetically sealed
expansible and collapsible case or capsule containing a liquid which boils at about
the temperature required for the water in the vessel herein before described and, the
provision for adjustment of the said thermostat consists or may consist of a spring
acted on by a screw.
Where the heating apparatus hereinbefore described is required for use where
the light produced by a gas jet is not objectionable the light proof shield herein-
before referred to may be dispensed with.
Dated this Fourteenth day of November 1894
W. T. WHITEMAN,
Agent for the Applicant.

page_text: Improvements in Apparatus for Imparting a Predetermined
Temperature to Liquids for Use in Developing Photo-
graphic Plates, and for other purposes.
I CHARLES EDWARD HEARSON of No. 5 Templar Street Camberwell in the
County of Surrey Engineer do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
In developing photographic plates it is important that the developing liquid be
brought to a standard temperature immediately before use and it is also desirable
that the developing dish be also brought to the same temperature. To provide
means whereby the said liquid and dish may be readily brought to the standard
temperature when they are about to be used is the object of my invention which
consists of the improvements hereinafter described in apparatus for imparting a
predetermined temperature to liquids for the said purpose and for other purposes.
According to my said invention I support a vessel for containing water above a
gas burner surrounded with a light proof shield having inlets and outlets for air
and I mount within the said vessel a thermostat which I so connect to a valve
governing the supply of gas to the burner that gas is allowed to pass thereto or is
shut off therefrom automatically according as the temperature of the water in the
said vessel is below or above a predetermined degree at which the thermostat will
act. I prefer to provide the thermostat with means for adjustment in order that
it may be caused to act at any desired temperature within a given range and I
provide for constant burning of a small jet of gas at the burner by means of a
by-pass the passage of gas through which is uncontrolled by the thermostat.
Within the said vessel I form passages which may consist of coils of tubing one of
which passages is connected with a supply of water which when warmed is used for
warming the developing dish and the other of which passages is connected with a
funnel to admit of ready introduction of the developing liquid and each of the said
passages is provided with an outlet pipe from which the liquids which become
warmed while flowing through the said passages are received as required.
The kind of thermostat which I prefer consists of a hermetically sealed expansible
and collapsible case or capsule containing a liquid which boils at about the
temperature required for the water in the vessel herein before described and the
provision for adjustment of the said thermostat consists or may consist of a spring
acted on by a screw.
A convenient form of the apparatus hereinbefore described is illustrated in
vertical section in Figure 1 of the accompanying drawing. In the following
description the parts of the apparatus illustrated are referred to by the letters and
figures marked on the said drawing.
a is the water vessel which consists of a metal cylinder closed at the lower part
and provided at the upper part with an outwardly projecting flange a¹ by means of
which the said vessel is connected to and supported within a metal casing 6 and
with an inwardly projecting flange a² which is secured to and supports a perforated
cylindrical diaphragm c within the said vessel. The passage for the developing
liquid consists of a tube coiled around the diaphragm c the several convolutions of
which tube are marked d d. The passage for the water for warming the developer
dish consists of another tube also coiled around the diaphragm c the several
convolutions of which tube are marked e e. d is the inlet end of the developer
tube. is the funnel connected thereto and d² is the exit end of the said tube.
is the inlet end of the water tube e which is connected to the water supply by

page_text: means of a flexible tube partly shown at e² and e³ is the exit end of the said water
tube. In order to admit of direction as may be required of the liquids issuing from
the exit ends de of the tubes de convenient lengths of flexible tube are connected
thereto portions of which flexible tubes are shown at d³ et. g is the gas burner for
heating the water in the vessel which burner is arranged within the lower part
of the casing b and is connected by tubes y g² g3 with the outlet of the valve box
hereinafter described. bare holes in the lower part of the said casing b for
admission of air to the said burner and 622 are holes at the upper part of the said
casing for exit of the products of combustion. 63 4 5 6 are baffles within the said
casing which prevent passage of light from the gas flame through the holes b².
b is a door closing an aperture 68 in the casing which admits of access to the gas
burner g. The arrows indicate the course through the casing 6 of the currents of
air entering by the holes bb.
The valve and valve box and the part in which is placed the thermostat by
means of which the passage of gas to the burner is controlled are shown detached
from the other parts of the apparatus in Figure 2 which represents a section of the
said valve and valve box taken in a plane at right angles to that in which the
section Figure 1 is taken the part containing the thermostat being represented in
elevation in the said Figure 2. Figure 3 is a plan of the valve box. In the
following description of the said parts all the figures of the drawing are referred to.
The valve box consists of two metal castings i secured together by screws h¹¹
and having formed in and between them passages for the gas and a hollow in which
the valve is arranged as hereinafter described. The passages for the gas which
are formed in the upper casting à consist of a tubular inlet communicating with
an annular hollow & formed around a central tube which is in direct communication
with the gas outlet m and communicates with the hollow both at its lower end
and by means of a small passage or by-pass o o' provided with a pin valve p. The
lower edge of the central tube constitutes the seating for the valve controlling the
main passage of gas from the inlet ; to the outlet m which valve consists of a piece
of oiled silk or other suitable flexible materialy held between the contiguous parts
of the castings h, i and having secured to its upper or acting side a disc of paper
or other slightly compressible material and to its underside a thin disc of cork faced
on its outer or lower side with a disc of metal 7'. The main gas passages which
are open when the valve 9 is away from its seating consist of the inlet the part
of the hollow k above the said valve the central tube and the outlet m. When
the passage between the valve y and its seating is closed by the rising of the said
valve gas is prevented from passing to the burner through the main passages but is
free to pass through the by-pass o o' which communicates between the hollow k
and the central tube 1. The said valve q is normally pressed away from its seating
by means of a spring r arranged within the central tube the compression of which
spring may be increased or decreased by turning in one or other direction a screwed
caps which is engaged with a screw thread formed on the outer face of the said
central tube and which bears on a cylindrical plug t resting on the upper end of
the spring r.
u is the thermostat which automatically actuates the valve thereby
controlling the flow of gas to the burner through the main passages of the valve
box. The said thermostat consists of an expansible and collapsible metal capsule
containing a liquid which boils at a temperature slightly lower than that required
for the water within the vessel a the construction of which capsule may be the
same as that described in the Specification of Letters Patent granted to me and
bearing date 4 August 1891 No. 13178. The said capsule is placed in a metal
box which is connected to the part of the valve box by means of a tube w of
such length that the said box will be below the level of the water in the vessel a
when the said vessel is sufficiently charged. is a rod resting on the said capsule
and touching or nearly touching at its upper end the metal facing q on the underside
of the valve q which rod is furnished with annular projections a¹ a loosely fitting the
interior of the tube w within which tube the said rod x is capable of moving freely
up and down. When by rise of temperature in the vessel a the capsule is caused

page_text: to expand its expansion pushes up the rod x pressing the valve q against its seating
and thereby closing the main gas passages in the valve box and consequently
reducing the size of the flame at the gas burner which is then fed with gas only
through the by-pass o o¹. On reduction of temperature in the vessel a below the
degree at which the liquid in the capsule u will boil the said capsule collapses and
allows the rud a to descend the valve g being then pushed away from its seating by
the spring and the main gas passages thereby reopened. y is a sliding collar
surrounding the tube w and engaged with a stud which projects from the rod
and is engaged with a slot w' in the said tube w which collar y has affixed to it a
wire z the free end of which passes through and projects above the part of the
valve box. The object of this arrangement is to admit of the valve g being raised
to its seating by hand when the pin valve p is being adjusted as hereinafter
described.
9
In order to prepare the said apparatus for use the parts shown in Figure 2
are removed and water of a temperature not higher than about sixty five degrees
Fahrenheit is poured into the vessel a until it is charged to the height of the upper-
most of the coils d, e. The said parts are then replaced the water inlet e is
connected to a supply of water the gas inlet j is connected to a supply of gas the
gas is turned on and the jet issuing from the burner g is ignited the tap of the
supply being turned until the flame at the burner is about the size of the bowl of
a dessert spoon.
The main gas passage in the valve box is then temporarily closed
by raising the wire and while the said passage is thus closed the pin valve p is
turned until the by-pass oo is sufficiently blocked to reduce the flame at the
burner to the size of a pea. The said wire is then released and the apparatus
is left untouched until the temperature of the water in the vessel a has risen
sufficiently to cause expansion of the capsule u whereby the valve q is pressed
against its seating through the medium of the rod a the main supply of gas bring
thus automatically shut off. If when this happens the water in the vessel a is
below the temperature required the pressure of the spring on the valve Y is
increased by screwing down the cap s on the central tube l of the valve box until
it is found that the closing of the valve q by expansion of the capsule is delayed
until the water in the vessel a has acquired the desired temperature. The
apparatus is then ready for use and is used as follows. Water from the water
supply to which the water inlet el is connected is admitted to the apparatus and
allowed to flow through it into the developing dish and to remain in the said dish
until it has acquired the temperature of the said water which is then removed from
the said dish. The photograph to be developed is then placed in the dish and the
required developing solut on is poured into the funnel and allowed to pass through
the apparatus into a vessel held or placed below the tube d secured to the exit
end of the coils d. The said solution which is heated to the required
temperature in passing through the apparatus is then used as required.
Although I have described my invention only in connection with photographic
operations I wish it to be understood that apparatus constructed substantially as
hereinbefore described is suitable for use in connection with other operations in
which liquids of a predetermined temperature are required.
Where the heating apparatus herein before described is required for use where
the light produced by a gas jet is not objectionable the light proof shield or casing b
herein before described may be dispensed with.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that
I claim ;- -
First. The improvements herein before described in such apparatus for heating
liquids as consists essentially of a vessel for containing water and arrangements for
heating the same and for admitting of passage through the apparatus of the liquids
to be heated and communication to the said liquids while so passing of heat from
the water in the said vessel that is to say the combination with such apparatus of

page_text: means for automatically maintaining a predetermined temperature of the water in
the water vessel substantially as herein before described.
Secondly. The general combination and arrangement of parts constituting the
apparatus hereinbefore described and illustrated in the accompanying drawings.
Dated this Twelfth day of August 1895.
W. T. WHITEMAN,
Agent for the Applicant.