Improvements in or Applicable to Heating Water by the Combustion of Gas and to the Automatic Regulating of the Gas Supply.
Year: 1888

page_text: Improvements in or Applicable to Heating Water by the Combustion
of Gas and to the Automatic Regulating of the Gas Supply.
We, CHARLES LLOYD BRAITHWAITE Junior and ISAAC BRAITHWAITE, both of
Kendal, in the County of Westmoreland, Manufacturers do hereby declare the nature
of this invention to be as follows:-
The invention relates to improvements for heating water by gas, and for obtaining
a mechanical motion on change of temperature applicable to the regulation of the gas.
In carrying out the invention, we arrango that the water coming from the heating
apparatus shall pass through a pipe, having a sufficient full between the two valves
to be hereafter described, and with the tap or taps, by which water is drawn from the
apparatus, below the lower valve. The upper valve is so arranged that the head of
water in the apparatus above it will be insufficient to open it, but that, when water
is drawn, the suction of the column of water between the two valves in addition to the
head will open it freely. We thus secure that when the water is drawn from the tap,
there is a reduction in the pressure immediately below the upper valve, and it is
this reduction in the pressure which we employ to open the gas supply, when the
water is drawn. This may be done in various ways, one of the simplest is as
follows:
A tube joined into the pipe (just below the upper valve) is connected with a chamber
behind a flexible diaphragm, of suitable material, placed at such a level below the
upper valve as to secure sufficient pressure of water to force the diaphragm against
the end of a pipe, through which the gas supply passes. When water is drawn from
the apparatus, the suction required to open the upper valve also draws back the
On closing the
diaphragm from the end of the gas pipe, thus setting on the gas.
water outlet, the suction is relieved by the passage of a small quantity of water
through a small hole through or beside the upper valve, and the pressure of the water
closes the diaphragm against the gas, thus shutting off the gas supply. The lower
valve, above mentioned, is to secure the escape of any air from the water, which
might otherwise accumulate in the pipe below the upper valve, and prevent its action.
It may consist of a valve opening in the direction of the current of water, but

page_text: From
weighted (or controlled by a spring) so as to cause a difference of pressure in the
water at the two sides of it. A very small byepass pipe is carried from immediately
below the upper valve to below the lower valvo. As the lower valve is weighted,
there is always a quick current in the byopass pipe, which removes any accumulation
of air, if even only a small quantity of water is drawn from the apparatus,
just below the lower valve a pipe is carried up to above the level of the head of water
to remove the air, and also to admit air in case the water is drawn from the taps
faster than the apparatus can supply it. In caso the taps are about the same level as
the lower valve ought to be, and when it is never required to draw less than tho
full quantity of water, the lower valve and byepass may be omittel.
To obtain a mechanical motion on change of temperature applicable for regulating
the gas supply a mechanical motion is produced by a slight change of temperature
at a given degree of heat, by enclosing in a completely sealel apparatus, part or all
of which may consist of a flexible motal box, a small quantity of liquid. The pressure
in this apparatus is adjusted by either exhausting or compressing the air contained
in it, until the boiling point of the liquid is brought to the temperature required.
We apply this to our water heating apparatus. in order to shut off the gas before the
effluent water reaches the boiling point. This we accomplish by placing a flat,
circular box, made of thin metal," with circular corrugations, in the current of the
outflowing water, close to the upper valve before mentioned. This box contains a
little liquid, preferably water, in which case the pressure is reduced to about half an
atmosphere, and the box is completely sealed. If the sides of the box are not in
themselves sufficiently elastic, a spring is enclosed in it. This box is so placed that
when it expands by the boiling of the inclosed water, a stud on the side of the box
presses against the spring, by which the upper valve is held closed, so as to tend to
open that valve, and allow the water to pass without diminishing the pressure below
it. In this way the gas valve is closed.
We apply the same principle also to shut off the main gas supply, in case the
pilot light, which is kept constantly burning, should by any means become extinguished.
For this purpose, a small closed metal vossel is placcil above the pilot light, connected,
by a tubo going downwards from the lowest part of it. to a thin metal box similar to
that last described. The box, pipe, and metal vessel are completely filled with spirit
when cold. When the pilot light is lighted, the spirit in the small vessel is boiled, and
the vapour produced drives all the spirit down the small tube into the flexible box,
till the pressure is such, that the boiling point of the spirit coincides with the
temperature of the point in the small pipe at which the surface of the spirit stands.
A spring valve, closing the gas supply, is held open as long as the flexible metal box
is thus distended. But if the pilot light goes out, the spirit vapour is condensed,
and the spirit again flows up the tube, and the flexible metal box contracts, so as to
liberate the spring valvo, which at once shuts off the gas supply.
n: ol
1000
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Patent Agents for the Applicants.

page_text: Improvements in or Applicable to Heating Water by the Combustion
of Gas and to the Automatic Regulating of the Gas Supply.
We, CHARLES LLOYD BRAITHWAITE, Junior, and ISAAC BRAITHWAITE, both of
Kendal, in the County of Westmoreland, Engineers, 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 :-
This invention relates to improvements in the heating of water by the combustion
of gas with the object of automatically controlling or regulating the gas supply by
cutting off or reducing the supply of gas at such times as the full flame is not required,
and to the obtaining of a mechanical motion on a change of temperature which may be
applied thereto.
The invention is primarily intended to be applied to instantaneous heating apparatus
of our own or of other construction to cut off or reduce the supply of gas:-1st when
the water ceases to flow from the heating apparatus 2nd when the heat of the water
reaches a given temperature, 3rd should the pilot light to the burner become
extinguished. In the first instance this is effected by creating a diminution in the
pressure of the water at a certain point in the pipes as it flows from the heating
apparatus and causing it to act direct upon a valve through which the gas supply
passes and in the second and third cases by means of a flexible metallic box or casing
containing a fluid from which a mechanical motion is obtained as it expands or
contracts consequent upon an increase or lessening of internal pressure as the
temperature rises or falls which acting upon a lever or otherwise opens or closes the
gas valve.
The invention will be fully described with reference to the accompanying drawings,
which will we consider be sufficient as an example to illustrate the invention without
showing or specifying other arrangements of apparatus whereby the invention may
be applied.
Fig. 1, is a diagram illustrating the general arrangement by which the invention
is applied.
Fig. 2, sectional elevation of a gas supply valve applicable in some cases for the
purpose of the invention.
Referring to the first part of our invention we construct or arrange the pipe
through which the water flows from the heating apparatus preferably with two
valves, one placed at a higher level than the other and with a considerable fall
between the two, the tap or taps through which the water is drawn from the
apparatus being placed below the lower valve. The upper valve is held to its seat by a
spring or weight or otherwise, with sufficient resistance to overcome the head of water
in the apparatus above it, but so that any slight reduction in pressure below it or of
the force of the spring will allow it to open. When water is drawn from the
apparatus the suction or reduction of pressure in the column of water between the

page_text: two valves will in addition to the head open the top valve, thus the drawing off of
the water from the tap will secure a reduction in the pressure immediately below
the upper valve and it is the variation of this pressure, at this point, which we
utilize to regulate the gas supply, the reduction in pressure when the water is drawn
being employed to open the supply valve which is closed when the pressure below the
valve increases again to that above it.
This may be carried ont in various ways, of which a simple form is illustrated in
the drawings.
In the discharge pipe A, leading from the heating apparatus the upper valve B, is
placed in any suitable position with a head of water above it. At any convenient
distance below the upper valve B, is placed a second or lower valve C, at a higher
level than the draw off taps. A tube D is jointed into the discharge pipe A at a
point immediately below the upper valve B. The tube D is connected with a chamber
of a diaphragm valve E, which controls the gas supply. The supply valve E is
placed at any suitable distance below the level of the upper valve B, to give
sufficient pressure to close the valve, and the tube D leads into a chamber e, behind
the flexible diaphragm e', (made of any suitable material) which is forced against its seat
when the pressure in the tube D overcomes the resistance of the diaphragm and the
pressure of the gas and thus shuts off the gas supply. The diaphragm valve may
be of any suitable form such as shown at E, with an internal pipe through which the
gas flows. A very small bye-pass is placed to connect the two sides of the upper
valve B, to equalise the pressure, when the drawing of the water has ceased and tho
valve is closed, and so close the gas supply valve E.
The function of the lower valve C, is to secure the escape of any air from the
water, which might otherwise accumulate in the pipe below the upper valve, and
prevent its action. It may consist of any suitable valve opening in the direction of
the current of water, but weighted (or controlled by a spring) so as to cause a
difference of pressure in the water at the two sides of it. A small ball valve is
shown in the drawing which acts very well. A very sunall bye-pass pipe F', is carried
from immediately below the upper valve B, to below the lower valve ( As the
lower valve is weighted, there is always a quick current in the bye-pass pipe,
which removes any accumulation of air, oven if only a small quantity of water is
drawn from the apparatus. From just below the lower valve (, an air pipe G, is
carried up to above the level of the head of water to remove the air, and also to
admit air in case the water is drawn from the taps faster than the apparatus can
supply it.
When water is drawn from the apparatus, the reduction in pressure or suction
caused below the upper valve B, before it opens, draws back the water from or reduces
the pressure in the pipe D, which connects with the supply valve E. On the pressure
in the pipe D, heing relieved the diaphragm of the valve springs or is drawn back
from its seating allowing a free supply of the gas to the burner. On closing the
water outlet the suction below the upper valve B, is relieved and the pressuro
equalized by the passago of a small quantity of water through the very small holo or
bye-pass which connects the upper and lower sides of the valve B, and the pressure
of water in the pipe D, shuts down the diaphragm onto its seat and thus closes the
gas supply.
Under certain conditions the lower valve and the column between it and the upper
valve may be dispensed with, for instance, when the draw off taps aro about the lovel
at which the lower valve ought to be placed, and it is not intended at any time to
draw off less than the full quantity of water, which the heater can supply; or when
there is sufficient head or pressure of water upon the upper part of the beating
apparatus to allow for an appreciable difference of pressure being established above
and below the upper valvo without the suction of a column of water below it. In
this case the difference in prossuro above and below the valve is utilized to regulato
the gas supply. Fig. 2, shows a suitable valve for effecting this which differs from
that shown at E, Fig. 1, in that it is provided with two chambers and two diaphragms,
one of which is in communication with the upper side of the valve B and the other

page_text: with the lower side of the valve B. The metal casing H is divided into two
compartments by the plate & forming, with the diaphragms I and J two chambers i
and j. The spindle K, passes through the plate and diaphragmns I and J and is
connected to the latter by the coupling plates k. A small hole or bye-pass h¹ connects
the two chambors or they may be connected by making the spindle slightly smaller
than the hole through which it passes. The diaphragm in one chamber preferably the
lower one acts as a valve to control the gas supply while the other acts to raise the
valve. The upper chamber is by the pipe L connected to the water above the upper
valve B, and the lower chamber by pipe M, with the water below the upper valve B,
the surface of the diaphragms upon which the pressure of the water acts being the
same area. It will follow that on water being drawn there will be a greater pressure
in the upper chamber than in the lower one which acting on the diaphragm I will
raiso the spindle K drawing with it the plate and diaphragm J and so open the gas
way O. On the flow of water being stopped at the outlet the pressure in both
chambers becomes the same, the spindle and diaphragms descend and the gas is shat
off by the pressure of the water above the diaphragm J.
Referring to the second part of our invention a mechanical motion is produced by a
slight change of temperature at a given degree of heat, by enclosing in a completely
sealed apparatus, part or all of which may consist of a flexible metal box, a small
quantity of liquid. The pressure in this apparatus is adjusted by either exhausting
or compressing the air contained in it, until the boiling point of the liquid is brought
to the temperature required. This we apply to the heating apparatus in connection
with a supply valve such as described to shut off the supply of gas before the offluent
water reachos the boiling point or to prevent the flow of gas when the water is being
drawn from the apparatus should the temperaturo of the water reach the maximum
degree. In the latter case we place a flat circular box P, made of thin metal, with
circular corrugations, in the current of the outflowing water, close to the upper valve B.
The box P, contains a little liquid, preferably water, in which case the internal pressure
is reduced to about half an atmosphere, and the box is completely sealed. If the sides
of the box are not in themselves sufficiently elastic, a spring p, is enclosed in it.
This box is so placed that when it expands by the boiling of the enclosed water, a
stud, on the side of the box presses against the spring R or lever by which the
upper valve is held closed, so as to tend to open that valve, and allow the water to
pass without diminishing the pressure below it. In this way the gas valve is closed.
We apply the same principle also to shut off the gas supply, in case the pilot
light S which is kept constantly burning, should, by any means, become extinguished.
For this purpose, a small closed metal vessel T, is placed above the pilot light,
connected by a tube or pipe t, to a thin metal box D', similar to that last described.
The box P, pipe t, and metal vessel T, aro completely filled with spirit when cold.
When the pilot light is lighted, the spirit in the small vessel T, is boiled, and the
vapour produced therein produces a pressure in the flexible box, which expands it, a
pin p", acting against a spring valve U, holds it open so long as the pilot light is
burning and the pressure which distends the metal box P¹ maintained. Should the
pilot light S be extinguished the pressure is reduced and the flexible metallic box P¹
contracts, liberating the valve U, which closes the other end of the gas way in the
valve E, by pressing two diaphragms with glycerine between them or other suitable valve
against the seat and this at once closes the gas supply. The gas flows to the
valve E, through the pipe V, and from it to the burner X, through the pipe VI, and
to the pilot light S, through the pipe v.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. The method of regulating the supply of gas to water heating apparatus which
consists in creating or maintaining two pressures in the delivery pipe and utilizing
the difference between such pressures to open the supply valve and allow the flow of
gas when the water is being drawn off, substantially as described.

page_text: 2. The method of regulating or cutting off the supply of gas to a water heating
apparatus by a mechanical motion obtained on a change of temperature by means of
a corrugated bulb or box containing fluid, which expands as the heat increases,
substantially as described and shown.
3. A heating apparatus having one or two valves hold or weighted against the
flow of water, placed in the delivery pipe to create a reduction of pressure at a
certain point therein for the purpose of opening and closing the gas supply valve,
substantially as described.
4. In an apparatus for heating water by the combustion of gas the combination
with a valve in the delivery pipe held to its place by a spring or weight to create a
reduction of pressure below it, of an expanding box or hulb which counteracts the
action of the spring or weight as the temperaturo increases, substantially as and for
the purposes
described.
5. In an apparatus for hoating water by the combustion of gas the combination
with the pilot light of an enclosed metal vessel placed to receive heat from the flame,
and an expanding metallic box or bulb by means of which mechanical motion is
obtained on a change of temperature and the gas supply shut off should the pilot
light become extinguished, substantially as described.
6. The means, substantially as herein shown and described for automatically
regulating the supply of gas to an apparatus for heating water by the combustion
of gas.