Improvements in Liquid Heaters.
Year: 1895

page_text: Date of Application, 29th Oct., 1895
Complete Specification Left, 9th July, 1896-Accepted, 12th Sept., 1896
PROVISIONAL SPECIFICATION.
Improvements in Liquid Heaters.
1, MOSES GRANT WILDER, of 816 Cherry Street, in the City and County of
Philadelphia, State of Pennsylvania, United States of America, Mechanical
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in devices for heating liquids by gas,
and the object of my invention is to produce a practically instantaneous liquid
heater which will be economical in the use of fuel, and in which there will be a
perfect combustion thereby preventing the discharge from the apparatus of
poisonous gases.
In my improved liquid heating apparatus I so arrange the burner that its
flame and heat will be concentrated within and upon the upper turns of a coil of
pipe in which the water or other liquid circulates from the bottom upward to
a discharge outlet. In order to conserve the heat of the burner the coil is
surrounded and covered, except at its lower end, with an inverted cup-shaped
heating chamber. This chamber is preferably composed of, or lined with, a non-
conducting mineral substance which may be heated, even to redness, without
injury. The burner is placed within the coil of pipe and well up towards the top
of the coil so that the hottest part of the flame is brought to bear upon the upper
end of the coil.
The heated gases from the burner pass through the interstices of the coil and
downward outside the coil and are discharged at the lower end of the cup-shaped
casing.
A flue or chimney within the coil surrounds the burner and separates the
ascending and descending currents of air and gas, the heated gases in passing
downward are thereby confined laterally between this chimney and the cup-shaped
casing and are compelled to circulate amongst the lower turns of the coil which
are kept cool by the inflowing liquid. The effect of this is to transmit a very
large proportion of the heat of the gases to the liquid circulating in the coil, and
the gases when discharged below the casing are reduced to a comparatively low
temperature.
With the above device I have obtained in practice a higher thermal efficiency
than is possible with any other apparatus for the same purpose of which I am
aware.
The inverted cup-shaped heating chamber is furnished at its top with a valve
which is adapted to be opened simultaneously with the shutting off of the gas
from the burner, aud to be closed simultaneously with the turning on of the gas to
the burner. The purpose of this device being to prevent the accumulation of
explosive or other gases in the heating chamber when the apparatus is not in use.
The means for operating this valve consist of a suitable system of links and cams
which are operated through the movement of the operating handles of the gas and
water valves.
Dated 10th day of October 1895

page_text: Improvements in Liquid Heaters.
1, MOSES GRANT WILDER, of 816 Cherry Street, in the City and County
of Philadelphia, State of Pennsylvania, United States of America, Mechanical
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 :-
My invention relates to improvements in devices for heating water or other
liquids by gas.
The object of the invention is to produce a practically instantaneous liquid-
heater which is economical in the use of fuel and in which there is perfect
combustion, thereby preventing the discharge from the apparatus of poisonous
gases.
In my improved apparatus I arrange for the concentration of the flame of the
burner within and upon the upper turns of a coil of pipe in which the water or
other liquid circulates from the bottom upward to a discharge-outlet. The coil is
surrounded and covered excepting at its lower end, by an inverted cupshaped
heating-chamber. The chamber is preferably composed of or lined with a mineral
non-conducting substance, which may become red hot on its inner surface under
the action of the burner without being injured. The burner is placed well up in
the coil, so that the hottest part of the flame acts upon the upper end of the coil.
The hot gases then pass through the interstices of the coil and thence downward
and discharge at the lower end of the cup-shaped casing. A flue or chimney
surrounds the burner within the coil, and the gases in passing downward are
confined laterally between the chimney and the casing and compelled to circulate
among the lower turns of the coil, which are kept cool by inflowing liquid. The
effect of this is to transmit a very large proportion of the heat of the gases to
the liquid circulating in the coil and the gases at the point of discharge below the
easing are reduced to a comparatively low temperature. In actual practice I have
attained a higher thermal efficiency with the present invention than is possible
with any other apparatus of the kind of which I am aware.
My invention further consists in other details of construction, all of which will
Le fully described in connection with the accompanying drawings, in which-
Figure 1 is a vertical central sectional view on the line A of Fig. 3. Fig. 2 is a
side elevation. Fig. 3 is a plan view, partly in section, on the line B of Fig. 1 ;
and Figs. 4 and 5 are details of the valve at the bottom of the burner, Fig. 5 being
a section on the line C of Fig. 4.
Referring to the drawings, 1 indicates an inverted cup-shaped casing open at
the bottom and normally closed at the top. The casing consists of or is lined
with some suitable refractory non-conducting material, and it rests upon a
perforated or slotted ring 2, which, in turn, rests upon a base 3. Within the
casing is a vertically-arranged coil 4, through which the liquid to be heated
travels upward. The coil preferably extends from below the bottom of the
casing to the top of the chamber within the casing. As shown, the supply of
liquid to the coil is controlled by a valve 5 and the hot liquid is delivered from the
upper end of the coil through a valve 6. Within the coil, and extending upward
from below the casing to a point somewhere near the middle thereof, is a flue or
chimney 7, and within the chimney is arranged a burner 8, which, as shown, is an
ordinary Bunsen burner.
The tue or chimney is so proportioned in diameter that only sufficient air to
effect complete combustion of the gas can pass upward between the burner and

page_text: flue. The chief purpose of the flue, however, is to separate the incoming air and
gases from the lower part of the coil and direct the outgoing products of com-
bustion onto the lower turns of the coil, so that the heat may be more completely
absorbed by the coil and transmitted to the liquid within. The gas is supplied
through a pipe 9, controlled by a valve 10. A pilot-light 11 is usually provided
for convenience for igniting the burner.
The operation of the invention, so far as it has been described above, is as
follows: The liquid being turned into the coil, so as to circulate upward therein
and the burner lighted, combustion will take place within the coil at or close to
its upper end, and the heated gases will then pass laterally out through the
interstices of the coil at the upper end and thence downward and cut through the
openings in the supporting-ring 2. The burner is placed well up in the chamber
of the casing, so that no direct heat from the flame is imparted to the lower part of
the coil, the chimney serving to partly protect the coil from this direct heat, as well
as to separate the incoming from the outflowing gases. The air-supply, which
comes in around the burner, passes up around the flame and serves to complete the
combustion of gases at the top of the chamber. Above the chimney 7 the current
within the coil is upward, and between the coil and the casing there is a downward
flow of the heated gases, but below the top of the chimney or flue the outflowing
gases may pass down either inside or outside of the coil, or the coil may be placed
in the middle of the space between the casing and the flue, thus compelling the
gases to travel on both sides of it and to impinge upon all parts of the lower half
of the coil. As shown in the drawings, the gases pass within the coil at the top of
the chimney and flow downward between the coil and the chimney, passing out
through the interstices of the coil at the bottom. Most of the heat of the gases is
absorbed by the cool liquid entering the coil, and any heat which is imparted to
the chimney is taken up by the cool air flowing to the burner. In this manner
nearly all of the heat which tends to escape is conveyed back to the top of the coil
upon which the hottest part of the flame plays. I have found that with this
arrangement a moderately strong stream of hot liquid can be obtained from the
heater in less than a minute, the temperature of the liquid and its amount of
course depending somewhat upon the size of the burner. The escaping products
of combustion I have found to be quite cool and free from deleterious gases. In
fact the cooling effect upon the escaping spent gases is such that the moisture in
them is largely condensed at the lower end of the coil, and I provide a trough 12
for carrying off the water of condensation. The force of the inflowing gas and the
highly-heated gases within the upper end of the coil create an upward current
which has sufficient force to drive the spent gases down through the annular space
between the chimney and the casing and out at the bottom. The interior of the
casing at the top becomes very highly heated, but if the casing be of suitable
material heat is prevented from passing through it, and as it has no other avenue of
escape except by traveling down the coil and over the cool lower portion of it, it
will be evident that nearly all of the heat-units are eventually imparted to the
liquid.
The gas-valve 10 is operated by a hand-lever 13 and the liquid-valve 5 is
operated by a similar lever 14. In order to conveniently arrange for turning on
the gas and liquid in proper proportions I connect the lever 13, by means of a
link 15, with a lever 16, having a slot 17, into which projects a pin 18 upon the
lever 14 of the liquid-valve. A set-screw 19 in the lever 16 projects into the slot
and regulates the length thereof. It will be seen that when the lever 13 is moved
to turn on the gas a certain amount of movement will be given to the lever 14 of
the liquid-valve, the amount of movement thus imparted depending upon the
position of the set-screw 19. If it be desired to increase the flow of liquid without
increasing the gas-supply the lever 14 may be moved independently to further open
the valve 5, the pin 18 being free to move in the slot 17 without disturbing the
position of the gas-valve. The effect of this will be to give a larger supply of
liquid at a lower temperature.

page_text: In Figs. 4 and 5 I have shown in side view and section a supplementary
gas-valve which may be employed to regulate the flow of gas in connection with a
thermostat. It consists of a casing 29, having an inlet 23 and an outlet 24, the
valve proper consisting of a fixed disk 20 and a moveable disk 21, arranged in a
chamber of a casing, the disks being provided with perforations which register
when the valve is open. The movable disk 21 is connected to a rocking stem 25,
provided with a lever 26, which is connected by a link 27 to any suitable
thermostatic regulator which is controlled by the temperature of the outflowing
liquid. The burner 8 is supported upon a ring 28, which is attached to the
casing 29 of the valve.
In order to ventilate the casing when the apparatus is not in operation, and to
prevent the accumulation of gas which might leak from the burner and produce
an explosive mixture, I provide an opening 30 in the top of the casing and a
valve 31, which normally closes said opening. The valve, as shown, is operated by
a rod 32, the lower end of which is connected to a lever 33, pivoted to the base.
The lever 33 carries a roller 34, which rests npon the link 15. Upon the upper
surface of the link is a cam 35, which, when the valves are thrown to shut off the
gas and liquid, raises the lever 33 and lifts the valve 31, thereby opening the
casing, so that the gases therein, may escape. As shown in the drawings, there is
an ornamental cap 36 upon the casing, provided with perforations 37 for
ventilation.
My invention is susceptible of various modifications in the matter of design and
mechanical detail without departing from the spirit thereof, and I do not wish to
be considered as limiting myself to the precise construction and arrangement of
parts illustrated and described.
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 what I
claim is―
1. In a liquid heater, the combination of an inverted cup-shaped casing normally
closed at its upper end, a burner located within the chamber of the casing, a coil
within the chamber, surrounding the burner, and extending from below the buruer
to the top of the chamber, said coil having its outlet at its upper end, and a flue or
chimney within the coil and surrounding the burner, the course of the gases from
the burner being first to the upper part of the chamber within the coil, thence
through the interstices of the coil, and thence downward between the flue and
casing and discharging at the lower end of the casing, the flue or chimney serving
to separate the ascending currents of gas and air from the descending products of
combustion in the lower part of the casing, substantially as described.
2. In a liquid beater, the combination of an inverted cup-shaped casing, composed
of non-conducting material, and normally closed at its upper end, a burner
located centrally within the chamber of the casing, a coil within the chamber,
surrounding the burner, and extending from below the burner aud casing to the
top of the chamber, said coil having its outlet at its upper end; and a flue or
chimney within the coil and surrounding the burner, the course of the gases from
the burner being first to the upper part of the chamber within the coil, thence
through the interstices of the coil, and thence downward between the flue
and casing and discharging at the lower end of the casing, the flue or chimney
serving to separate the ascending currents of gas and air from the descending
products of combustion in the lower part of the casing, substantially as described.
3. The combination of the inverted heating chamber, a gas burner discharging
its products upward into said chamber, a valve and valve seat in the top of said
chamber, and means for opening said valve simultaneously with the shutting off of
the gas from said burner and for closing it simultaneously with the turning on of
the gras.
4. The combination in a liquid heater, of an inverted cup-shaped heating
chamber, a coil of pipe within said chamber receiving liquid at the bottom and

page_text: discharging it from the top, a flue or chimney within said coil, a burner within said
flue, a gas cock, a safety valve in the top of said cup-shaped heating chamber, and
means for automatically opening said valve when the gas cock is closed and for
closing it when the gas cock is opened.
5. The combination in a liquid heater, of a vertical normally closed heating
chamber, a coil of pipe within said chamber, a valve for controlling the flow of
liquid to the lower part of said coil, a gas burner within said coil, a valve for
controlling the flow of gas to said burner, a link connecting the operating haudles
of the gas and water supply valves, a cam ou said link, a valve for closing the top
of the heating chamber and means operated by the cam for opening the last named
valve when the gas valve is closed, substantially as described.
Dated this 30th day of June 1896
MOSES GRANT WILDER.
D. Young & Co.,
11 and 12 Southampton Buildings, London, W.C.,
Agents for the Applicant.