Improvements in and relating to Apparatus for Heating by Steam.
Year: 1892

page_text: Date of Application, 10th May, 1892-Accepted, 2nd July, 1892
COMPLETE SPECIFICATION.
Improvements in and relating to Apparatus for Heating by Steam.
I, WALTER BURNHAM, of 57, West Lake Street, Chicago, County of Cook,
Illinois, United States of America, Steam Engineer, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particularly
lescribed and ascertained in and by the following statement:-
This invention relates to apparatus for heating by steam, and is designed to
provide for the efficient regulation or control of the action of such apparatus,
and for the return to the generator of the water of condensation from the said
apparatus.
The main object of the said invention is to provide for advantageously applying
to heating-coils the apparatus described in the Specification of my former Letters
Patent No. 18,435 dated 18th December 1888, which apparatus is now known in
the trade as a ❝ steam loop."
In the use of large steam-coils, as heretofore constructed and operated, for
heating water, the following facts commonly exist, namely:-1st. The radiation
from the coil is so great that the inlet of steam must be at first partially closed,
or the boiler-pressure would fall, which partial closing of the steam-inlet reduces
the pressure in the coil. This would necessitate the use of an impracticably high
steam loop. 2nd. All of the steam delivered into the coil is condensed and the
drainage from the coil is solid water, which would render the application of a
direct steam loop impossible.
To secure the desired object, therefore, I govern the amount of condensation
taking place in the coil, whilst maintaining approximately boiler-pressure therein,
and connecting therewith the steam loop.
In the accompanying drawing:
--
Figure 1 is a sectional elevation of an apparatus embodying my invention.
Figures 2 and 3 are detail views, showing modified forms of some of the parts.
A is a steam-generator, B a tank containing water to be heated, C a steam-coil
located in the lower part of the said tank, D a steam supply pipe leading from the
steam generator to the upper end of the coil. E is a steam loop or return pipe,
constructed as described in my said former Specification, and adapted for returning
water of condensation from the steam-coil into the generator by the direct action
of steam and without the agency of any pump or similar mechanical device, the
said steam loop comprising a riser E', a drop leg E', and a horizontal E³ connecting
the said riser with the drop leg. The said drop leg enters the boiler at a point
below the water-level therein and is adapted to contain a pressure balancing
liquid column, above which is located a space, subject. to low pressure, towards
which steam flows through the riser, and into which water is carried or swept
upwardly in the form of short pistons filling the bore of the riser, or of waves on
the sides of the riser, or of globules suspended in the steam, by steam which
passes upwardly through the riser to the upper part of the loop, as fully set forth
in my said former Specification.
Fis a pipe forming a continuation or branch of the pipe D, and leading down-
ward to and connected at its lower end with the riser E. G is a pipe connected
with the lower end of the coil C, and leading downward to and connected with the
lower end of the riser E'. The said pipe G is provided with a regulating valve
and a check-valve g', which valves are herein shown as located in a lower hori-
zontal part of the said pipe G. H is a pipe connecting the lower end of the steam-
coil with the pipe F. The pipe H is provided with a valve h, and the pipe F is
provided with a valve located between the upper end of the coil C and the
junction of the pipe H with the said pipe F, c is a discharge pipe at the lower end

page_text: of the coil C, the same being controlled by a valve c¹. C¹ is a valve controlling
the passage of steam into the upper end of the coil C.
The operation of the parts constructed as above described is as follows:-
Supposing the coil to be cold, the valve C' is opened and the valve c¹ slightly opened,
and all air thereby blown out of the coil. The blow-off valve c¹ is then closed,
and the valves f, g, and are opened so as to place the return system in operation,
or, in other words, to effect the return to the boiler through the loop E of water
of condensation accumulating in the pipes D and F, the coil C, and pipes G and H,
back to and into the generator. If now the valves g and h are closed, water of
condensation will fill the pipe G and coil C, and the pressure in the return system
will then be greater than the steam-pressure acting through the coil upon the
upper end of the pipe G. The water column in the said pipe G will, however, act
upon the valve g with a pressure which, when added to that of the steam upon
the upper end of the said water column, will be greater than the steam-pressure in the
return system. It follows that, if the valve g be opened, water will flow from the
coil through the pipe G and valves g, g-into the riser E', and will be returned
to the boiler by the action of steam passing through the steam-pipe and
carrying the said water in separated or detached masses upward through the
riser. As water is drawn from the coil, the coil will be filled with steam, and
it follows that, by opening the valve g to a desired extent, water may be allowed
to escape from the coil just as fast as it will accumulate therein by condensation
when the apparatus is working under normal conditions. That is to say, assuming
that all of the steam made in the generator is employed for heating water in the
tank, then the valve g may be turned to allow the escape of water of condensation
from the coil at the same rate that it is condensed therein, and this can be
determined by gradually opening the said valve g until the boiler-pressure begins
to fall, when the maximum amount of water which the boiler can evaporate and
still hold a desired steam-pressure will be determined. In other words, assuming
the boiler will evaporate two gallons of water per minute and the valve g is set so
that only two gallons of water per minute can pass through it, then the water
evaporated will be condensed in and escape from the coil as fast as it is produced,
and all the steam made will be employed in heating the water in the tank B.
Furthermore, any increase in the quantity of water allowed to escape from the
coil, will result in a lowering of the boiler-pressure, because the balance between
evaporation and condensation will then be destroyed and more steam will be
condensed in the coil than is produced in the boiler. By so controlling the exit of
water of condensation from the coil, therefore, the amount of condensation in the coil
may be governed or controlled without reference to the temperature of the water;
it being obvious that, if the water is so cold as to produce more water of con-
densation than can escape through the valve, then the coil will be filled with water
up to a point where the steam-space is so reduced as to give a condensing surface
sufficient only for condensing that quantity of water which will pass through the
regulating valve. It follows that, as the heat of the tank-water increases, conden-
sation in a given steam-space of the coil will be diminished, but, as a definite
quantity of water is drawn off through the regulating valve, if the steam-space
in the coil is so small as to produce water in quantity less than is drawn off, the
steam-space will be increased and will continue to increase until the amount of
condensation is just equal to the quantity of water discharged, when evaporation
'and condensation will again be in equilibrium. When the tank-water is very hot,
the coil will be entirely filled with steam, in which case the valve f may be closed
and the valve opened, when the coil will be thrown into direct circuit with the
return system, and water of condensation as fast as it is formed will pass into
the riser of the return or steam loop and will be carried back to the boiler.
follows from the above that, by the use of the apparatus, described, the water in
the tank may be kept at any temperature desired and the full or any desired boiler
pressure retained in the coil and return system. Such regulation may be easily
effected by manipulation of the valve, the lever of which is shown as arranged
It

page_text: to pass over a divided or graduated segment g³, by which the extent of-its
movement may be easily seen and controlled. It is obvious, for instance, that the
lower the temperature which it is desired to retain in the tank, the less steam will
be used and the less condensation will take place. The valve g will, therefore,
be set to allow the escape of a less quantity of water from the coil when a lower
temperature in the tank is desired; cutting off the escape of water of condensation
obviously resulting in the coil becoming partially filled and a consequent reduction
of the steam space and of the amount of steam condensed. Similarly, to secure
a higher temperature of water in the tank, the valve g is opened to allow the
escape of a greater quantity of water from the coil in a given time, and a greater
part of the coil will then be filled with steam, the amount of heat lost in con-
lensation or conduction will be greater and the quantity of water condensed will
be proportionally greater. Finally, when the desired temperature is so great as
to require that all of the coil should be filled with steam to accomplish the
heating of the water, then the valve may be opened as before described, and
the coil brought into direct connection with the return system. The apparatus
described, therefore, constitutes a means of regulating perfectly the temperature
of the water in the tank.
Such apparatus also affords a means of automatically regulating the quantity of
steam used so as to prevent lowering of the pressure in the boiler, because, as
before stated, if condensation in the coil increases so as to produce more water of
condensation than can escape through the regulating valve g, then the steam-space
of the coil will be diminished by the filling of the coil with water, and the amount
of steam used thereby decreased until condensation is so small as to call for the
normal consumption of steam only.
In the apparatus described, regulation may be accomplished otherwise than by
the use of the valve g as above set forth. For instance, let it be assumed that the
evaporating capacity of the boiler is two gallons and that said valve is set to
allow the escape of three gallons per minute when the valve C₁ is open and the coil
subject to the full steam pressure. If the said valve C is then closed so as to shut
off three fourths of the steam passage, the small amount of steam passing through
it cannot maintain a high pressure of steam because the steam-pressure in the coil
added to the water-pressure in the descending pipe G do not equal at the check-
valve the pressure in the return system. Under these conditions, therefore, the
said check-valve remains closed and no water will pass from the coil, but it will
remain in the coil so as to reduce the steam-space thereof until the small quantity
of steam passing through the valve C will keep up the boiler pressure therein,
when the increased pressure thereby produced on the water-column in the pipe G
will enable the water to flow ont through the check-valve to the return system. It
follows, therefore, that regulation may be effected either by the use of the valve C¹
or of the valve gor by both valves.
In Figure 2 I have shown a construction in which the lower part of the pipe F is
enlarged and the pipe G located within the same. In this construction the steam
in F transmits its heat to the water in the pipe G which is of about the same
temperature when it enters the said pipe G as the water in the tank. By this
construction, therefore, I utilize the steam which is constantly passing through the
pipe F during the operation of the return system, for heating the water of con-
densation before the latter passes into the return system and is carried back to the
generator. In small pipes the water when carried along with the steam or air may
move in pistons filling the bore of the pipe. In such case the air or steam will pass
the regulating valve g very rapidly, but the piston of water following it at a high
speed, will be instantly stopped when it reaches the said valve g, thereby producing
a shock or 46 water-hammer." To prevent this result I greatly enlarge the pipe G
at its upper end so as to form a chamber 9 in which the water may pass around
the air or steam instead of passing along with it, thereby securing a solid body of
water at the valve g.
The difference in pressure between the steam within the coil and that in the

page_text: return system determines the extent of steam area in the coils necessary to keep up
a certain pressure, it being obvious that the height of the water-column in the
pipe G must be such as to balance the pressures in the coil and return systems, so
that the greater the differences in pressures the higher will be the said column.
The height of the water-column in the pipe G is, therefore, one of the factors by
which the extent of the steam-space in the coil is determined.
is
Figure 3 shows a construction in which regulation is effected by changing or
shifting vertically the position of the lower end of the water-column in the
pipe G.
In this instance, the pipes F and G are connected by horizontal
passages, f, f, f³ etc. at different heights. When the water is cold and a dis-
charge of a small quantity only of the water of condensation from the coil is
When the
desired, the highest passage f¹ is opened and all the others left closed.
tank-water becomes hotter, one of the lower cross-pipes is opened and the upper
one is closed. If the valves in all of the cross-pipes are closed and the valve
also closed, water will fill the said pipe G and the coil and none can escape. If,
however, one of the lower valves is opened, water will pass through the corre-
sponding cross-pipe and will act against the steam pressure in the return system
with a pressure due to the steam-pressure in the coil added to the weight of the
column of water in the pipe G and coil C above the cross-pipe through which water
is escaping. When one of the lowermost valves is open, this water-column will fill
only a small part of the coil, and thus give a large steam-space therein, while, if
one of the uppermost valves is open, the water-column will nearly fill the coil, and
a relatively small steam-space will be afforded in the said coil. It follows, there-
fore, that, by opening one or other of the cross-pipes, the steam area of the coil
may be controlled so as to increase or decrease the quantity of steam condensed in
the coil, and to thereby regulate the quantity of steam used.
The apparatus shown in Figure 3 has the disadvantage of not being automatic or
of requiring hand manipulation of the valves to secure proper results, and this form
is herein shown solely for the purpose of more fully illustrating the principles
involved in the regulating devices, and is not recommended for practical use.
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 :-
First. The herein described method of regulating or controlling the action of
steam heating apparatus, by the employment of a column of water between the
said coil and a steam-loop, such as I have herein before referred to, by which
the water of condensation from such apparatus is returned to the steam-generator.
Second. The combination, with a steam-generator, a heating-coil, and a steam-
loop, such as I have hereinbefore referred to, for returning the water condensed in
the coil to the generator, of suitable means for controlling at the drainage end of
the coil the exit of water of condensation therefrom to the steam loop, substantially
as described.
Third. The combination, with a steam-generator, a steam heating-coil and a
steam-loop, such as I have herein before referred to, for returning the water of
condensation from the coil to the generator, of a depending pipe connected with the
lower end of the coil to afford a water-column adapted to overcome the difference
in pressure between the coil and the steam-loop, substantially as described.
Fourth. The combination, with a steam-generator, a heating-coil and a steam-loop
such as I have hereinbefore referred to, of a depending pipe connected with the
lower and discharging end of the coil and with the steam-loop, to afford a water-
column of sufficient height to overcome an excess of pressure in the loop over that
in the coil, and means for controlling the exit of water from the said pipe into the
steam-loop, substantially as described.
Fifth. The combination, with a steam-generator, a heating-coil and a steam-loop,
such as I have herein before referred to, for returning the water condensed in the
coil to the generator, of a depending pipe connected with the lower and discharging

page_text: end of the said coil and delivering into the loop, and a valve for controlling the
flow of liquid from the said pipe to the said steam-loop, substantially as described.
Sixth. The improved apparatus constructed substantially as described with
reference to either of the forms or modifications shown in the accompanying .
drawings and operating as, and for the purposes, above specified.
Dated this 10th day of May 1892.
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.