Improved Method of and Apparatus for Automatically Regulating the Temperature and Circulation of Liquids in Boiling or Heating Tanks.
Year: 1894

page_text: Date of Application, 9th July, 1894
Complete Specification Left, 8th Apr., 1875-Accepted, 11th May, 1995
PROVISIONAL SPECIFICATION.
Improved Method of and Apparatus for Automatically Regulating
the Temperature and Circulation of Liquids in Boiling or
Heating Tanks.
I, FREDERICK NOEL MACKAY, of 242 York Road, King's Cross, in the County
of Middlesex, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to a method of and apparatus for automatically regulating
the supply of steam to steam-heated boiling or heating tanks, and for inducing
perfect circulation in such tanks.
The objects of my invention are to so provide that the temperature of the liquid
in the tank is kept practically uniform; and to promote circulation of the liquid
especially in the lower parts of the boiling tank, so as to obtain a uniform or nearly
uniform temperature throughout the liquid.
My invention is applicable to tanks heated by steam flowing into the liquid itself
and to tanks heated by steam boiling coils.
In carrying my invention into practice for the regulation of the steam supply,
I provide a hollow metal drum, open at the bottom, and closed at the top, and
arranged to float in the liquid in the tank. The drum rises and falls in accordance
with the increased or decreased buoyancy of the same due to the varying vapour
pressure contained in the upper part of the same. The vapour pressure varies
with the alterations of temperature of the liquid in the tank. These vertical
movements of the drum, by means of suitable connections with the steam supply
cock or the like, regulate the steam supply to the tank. I so arrange that the
liquid in the drum is always heated to a higher temperature than the main
body of the liquid in tank. I introduce the steam into the liquid within or just
under the drum.
To induce circulation of the liquid in the tank I provide a suitable vessel which
may be somewhat cone-shaped and having an outlet at the top and inlets at the
bottom, and I arrange the same over the steam coils. The liquid in the said
vessel above the coils becoming heated rises and passes out through the top
of same and draws in at the bottom colder liquid, thus setting up a circulation of
liquid.
I will now more particularly indicate how I may carry my invention int▸
practice.
My improved steam-regulator consists as before stated of a hollow drum open at
the bottom and closed at the top and immersed in the liquid to be heated. The
drum is fixed to a guide-rod, working in suitable guides, one end of the rod being
connected by suitable gear to a valve, steam-cock or other appliance for controlling
the flow of steam to the liquid to be heated, or in the case in which a boiling coil is
used, to the steam supply to the same.
Underneath the open end of the drum I preferably place a small supplementary
boiling-coil or similar appliance, through which steam passes on its way to the
liquid or to the main boiling-coils, so that the liquid immediately under the mouth
of the drum may be subjected to the highest temperature to ensure its being at
boiling point before the main body of liquid in the tanks. When no main boiling-
coil is used I may dispense with the supplementary heater steam being admitted to
the liquid within or immediately under the drum.

page_text: Balance weights may be placed on the drum or on the lever or other gear-
connecting the drum to the cock or valve which controls the steam supply. By
this means the drum can be made more or less buoyant according to the temperature
that it is desired to maintain in the liquid being heated. For example, when the
liquid is desired to be maintained at the full boiling temperature or above it, the
drum is then weighted, so that it does not rise and cut off the steam supply as soon
as it does when not so weighted; when a lower temperature is required in the tank,
the drum is rendered more buoyant by counter weights placed on the before
mentioned lever.
I place the cold liquid supply inlet to the tank directly under the open end of the
drum, and by means of a spray pipe or similar device cause the entering cold liquid
to act on the small supplementary boiling-coil which lessens at once the temperature
about the said coil.
The in-coming liquid can be also caused to spray into the vapour space above
the liquid at the upper end of the drum, which causes immediate condensation of
the vapour.
The effect of this is to immediately cause the drum to fall, thereby allowing steam
to enter the liquid or the boiling coils, as the case may be, and so the desired
temperature of the liquid is maintained.
When the apparatus is first started the liquid in the tank being cold, the drum
falls to its lowest level, and as soon as the temperature rises by the action of the
steam to such a point that vapour of sufficient pressure is given off, this vapour,
rising into the upper part of the drum, increases its buoyancy and causes it to rise
and so shut off steam.
When a fresh supply of cold liquid enters the tank it cools the small coil under
the drum and condenses the vapour inside the drum. This causes the drum to fall
and thereby turns on the steam again.
By these means a nearly uniform temperature in the liquid being heated is
automatically obtained. A vacuum and pressure valve separately or combined may
be fitted to the top end of the drum. This ensures air being discharged from the
inside of the druin at starting, and prevents a vacuum being formed inside the
drum.
The level of the liquid in the tank is maintained by an automatically acting ball
and cock placed by preference in a small vessel external to the main tank but
connecting therewith through a suitable pipe.
To obtain a good circulation throughout the tank I cause the heated liquid above
the coils to be collected in a double cone or other suitable shaped vessel which
vessel is placed over the heating coils. The liquid when heated passes out at the
top of said vessel through an injector shaped outlet, so formed that the partial
vacuum formed by the outflowing heated liquid, causes the colder liquid from under
the coils to rise up and flow out at the top of the vessel along with the heated
liquid. The cold liquid is replaced by other liquid from the tank which liquid
enters by suitable openings at the lower end of the cone. I sometimes provide pipes
connected with the cone and extending to near the sides of the tank to ensure that
the cone shall draw the liquid from the remotest parts of the tank.
I may dispense with the vessel described above and instead thereof use a simple
cone shaped or other vessel which is fitted over or onto or forms a part of the steam
coils. The liquid above the pipes as it becomes heated rises and passes out
through the opening in the top of the vessel. Colder liquid from below the coils
comes into the vessel at the bottom to take the place of the ascending heated
liquid.
By either of these methods a good circulation of the liquid is obtained thus
maintaining approximately the same temperature throughout the tank.
The circulator is most effective when placed on the steam coils nearest to the
steam inlet.
It can if desired be provided with a separate steam supply arranged to work
independently of the main boiling coils.

page_text: The simple cone or other shaped circulator may be used to promote circulation
in a different manner than that previously described. If the mouth at the top of
the same is closed, the steam gecerated in the vessel by the heat of the coils will be
forced to pass out through the bottom of the vessel and thus bubbling up through
the liquid will cause circulation of the same.
By the use of circulating apparatus of these kinds I am able to dispense with the
use of agitators or like appliances that have to be worked by power to give the
requisite circulation to the liquid being heated in the boiling tank.
Dated this 9th day of July 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improved Method of and Apparatus for Automatically Regulating
the Temperature and Circulation of Liquids in Boiling or
Heating Tanks.
I, FREDERICK NOEL MACKAY, of 242 York Road, King's Cross, in the County
of Middlesex, 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 a method of and apparatus for automatically regulating
the supply of steam to steam-heated boiling or heating tanks, and for inducing
perfect circulation in such tanks, and has for its objects to maintain the liquid in
the tank at a constant temperature and to so promote the circulation of the liquid,
especially in the lower parts of the tank, as to obtain a uniform or nearly uniform
temperature throughout the whole body of the liquid.
The chief feature of my invention is the use of the pressure of the vapour given
off by the liquid for governing the admission or exit of the steam.
My invention is applicable to those apparatuses where the steam flows into the
liquid as well as to those where the steam circulates through coils and does not come
into contact with the liquid.
In the accompanying drawings
Figure 1 is a vertical section of a tank having my improvements applied
thereto.
Figure 2 is a plan of a detail hereinafter described drawn to a smaller scale.
Figure 3 is a vertical' section of a device for improving the circulation of the
liquid in the tank.
Figure 4 is a plan of said device.
Figures 5 and 6 are similar views of a modified form of the circulating
device.
Like letters of reference denote corresponding parts in the several figures.
A is the tank containing the water or other liquid to be heated; B is the inlet
pipe and C the outlet pipe for the liquid. D is the steam coil for heating the
E is a valve in
liquid; d is the inlet pipe and d¹ the outlet pipe for the steam.
the inlet pipe d. In lieu of said valve I may use a cock or other equivalent
device. is a metal drum cr floating hollow vessel forming part of a device for
controlling the steam as will be hereinafter described. Connected with the inlet
pipe B is a shallow pan or dish G through which the bulk of the liquid entering-
the tank passes. The liquid flows over the rim of the dish in a thin cascade and is
thereby distributed over the surface of the liquid in the tank. To ensure that the
delivery of liquid shall be substantially uniform all round the rim of the dish,
I provide the said dish with a thin circular cover G' secured at its centre to a

page_text: bridge piece g.
The said cover has a number of radial slits as shown in Figure 2
extending from the outer edge nearly to the centre, and is thereby made very
flexible. The cover presses lightly on the rim of the dish and thus operates to
spread the liquid and to ensure as before stated that the liquid shall escape
uniformly all round the rim of the dish. In some instances the cover may be a
valve mounted on a spindle so that the whole of the cover may rise when the water
presses against it.
At the end of the pipe B is a rotary nozzle H or other form of spraying device
for a purpose hereinafter described.
The hollow metal drum or vessel F is open at the bottom, and closed at the top,
and is arranged to float in the liquid in the tank. It is attached to a central tube f*
that slides upon and is guided by another tube f' which is fixed to the cover of the
tank, or to a bracket fixed to the tank. J is a lever pivoted at J₁ to the tank and
connected at its inner end by pins f² to the tube f. The said lever is also connected
to the spindle e of the valve E. Jare balance weights hung on the outer end of
the lever. Within the tube f¹ and resting on the lower closed end of the tube f is
a rod K on which are placed balance weights K' that are so adjusted with reference
to the weights J as to give the desired balance to the drum F. The drum rises
and falls in accordance with its increased or decreased buoyancy due to the varying
vapour pressure contained in the upper part of the same, which vapour pressure
varies with the alterations of temperature of the liquid in the tank. These vertical
movements of the drum, operate through the lever J to open and close the valve E
and thus to regulate the steam supply to the tank. By means of the balance
weights the drum can be made more or less buoyant according to the temperature
that it is desired the liquid shall have. For example, when the liquid is desired to
be maintained at the boiling temperature or above it, additional weights are applied
to the rod K so that the drum does not rise and cut off the steam supply as soon as
it does when not so weighted; when a lower temperature is required in the tank,
the drum is rendered more buoyant by counter weights placed on the before
mentioned lever J. I arrange that the liquid within the drum shall be heated to a
somewhat bigher temperature than the main body of the liquid in the tank for
which purpose I provide within the mouth of the drum a box into which the
steam euters before passing to the coil or heating device D, so that the liquid in
the mouth of the drum is subjected to the highest temperature and will reach the
boiling point before the main body of liquid in the tank.
The incoming liquid discharged from the nozzle H is sprayed on the upper end
of the drum, and causes immediate condensation of the vapour or a portion thereof
in the drum whereupon the drum descends and opens the valve E thus allowing
more steam to enter the coil D. By this means the temperature of the liquid is
maintained at its normal level.
When the apparatus is first started, the liquid in the tank is cold and the drum
is at its lowest level; as soon as the temperature rises by the action of the steam to
such a point that vapour of sufficient pressure is given off, this vapour, rising into
the upper part of the drum, increases the buoyancy of the drum and causes it to rise
and so shut off steam. When a fresh supply of cold liquid enters the tank it
condenses a portion of the vapour inside the drum, and causes the drum to descend
and thereby turn on the steam again, as above described. By these means the
temperature of the liquid is maintained practically uniform. F is a pet cock by
which the discharge of the air from the inside of the drum at starting may be effected.
and by which at other times air may be admitted to the drum to prevent the
formation of a vacuum within the drum.
The level of the liquid in the tank is maintained by an automatically acting ball-
cock L placed by preference in a small vessel M external to the main tank but
communicating therewith through a pipe M'. The level of liquid in the vessel M
will be the same as that in the tank A.
The above described apparatus serves to control the supply of steam to the
coil D; it may however be arranged to control the outlet of steam from the coil,

page_text: for the same purpose. The same controlling apparatus may be used with slight
modifications in those instances where a coil D is not used. In such a case the
heating box is dispensed with and the steam is introduced into the tank just under
or within the mouth of the drum F.
To obtain a good circulation of the liquid in the tank, I, according to one con-
struction, rest on the heating coil D a double cone N Figures 3 and 4 open at the
apex as shown. From the base of the cone are suspended a number of tubes N'
which extend nearly to the floor of the tank. The heated liquid within the inner
cone passes out at the top of the said cone through the injector shaped outlet
thereof, and induces a partial vacuum in the annular space between the cones which
vacuum causes the colder liquid from under the coils to rise up the tubes N¹ and
the annular space aforesaid and flow out at the top of the outer cone along with the
heated liquid. The cold liquid is replaced by liquid from other parts of the tank
and thus a good circulation is established which ensures an approximately uniform
temperature throughout the liquid. I sometimes provide pipes N' Figures 5 and 6
connected with the cone and extending to near the sides of the tank to ensure that
the cone shall draw the liquid from the remotest parts of the tank.
I may dispense with the double cone described above and instead thereof use a
simple cone-shaped or other vessel N as shown in Figure 5 which is fitted over the
steam coils and is combined with a vessel N³ that rests on the floor of the tank.
Openings N are provided in the lower edge of the vessel N³ to allow the liquid to
pass into the vessel. The liquid above the pipes as it becomes heated rises and
passes out through the opening in the top of the cone and the colder liquid from
below the coil comes into the cone at the bottom to take the place of the
ascending heated liquid. The cone may be jacketed with air, or other non conductor
of heat.
The circulator is most effective when placed on the steam coil at a point near to
the steam inlet.
It can if desired be provided with a separate steam supply arranged to work
independently of the main boiling coil D. In some instances the cone may be
closed at the apex and still be used to promote circulation. In such a case the
steam generated within the cone by the heat of the coil D will be forced to pass
out through the bottom of the vessel and bubbling up through the liquid will cause
circulation of the same.
By the use of circulating apparatus of these kinds I am able to dispense with the
use of agitators or like appliances that have to be worked by power to give the
requisite circulation to the liquid.
Although I have hercinabove referred to steam as the heating medium, I wish it
to be clearly understood that I may use other media than steam, for example I may
use a heated vapour or gas.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In apparatus for heating water or other liquid by steam, heated vapour or gas,
a device for governing the admission or the exit of the heating medium, said device
being automatically controlled by the pressure of the vapour given off by the liquid,
for the purpose specified.
2. The floating drum or vessel open at the bottom and having the liquid therein
subjected to the greatest heat within the tank, and connected to the valve in the
steam inlet or outlet pipe, for the purpose specified.
3. Introducing the cold liquid supply in such a manner as to condense the vapour
in the drum, for the purpose specified.
4. The device comprising the floating drum or vessel F furnished with a suitable
guide, the means for balancing the said drum, and the connection with the valve E,
substantially as, and for the purpose, specified.
5. The combination, with the aforesaid device, of means such as the box d³ for

page_text: heating the liquid in the drum and other means such as the nozzle H for discharging
cold liquid on the drum to condense the vapour therein, substantially as, and for the
purpose, specified.
6. In the aforesaid apparatus for boiling or heating liquid by means of steam, or
heated vapour or gas, the device comprising the dish G and slit flexible cover G₁
for distributing the cold liquid supply, substantially as, and for the purpose,
specified.
7. The combination, with the steam coil or heating device, of a single or
double cone for inducing free circulation of the liquid in the tank, substantially as
described.
8. The means for inducing circulation of the liquid in the tank, constructed
substantially as described with reference to Figures 3 and 4 or to Figures 5
and 6.
9. The apparatus constructed substantially as described with reference to
Figure 1 for the purpose specified, said apparatus being a combination of steam
regulator, liquid regulator, liquid distributor, and liquid circulator, so constructed
and arranged as to automatically regulate the temperature of the liquid in the
boiling or heating tank or vessel.
D
1
1
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.