Improvements in Water-tube Steam Generators or Water Heaters.
Year: 1895

page_text: Date of Application, 26th Apr, 1895
Complete Specification Left, 25th Jan., 1896-Accepted, 21st Mar., 1896
PROVISIONAL SPECIFICATION.
Improvements in Water-tube Steam Generators or Water Heaters.
EDWARD THOMAS DARKE Secretary of The Association for the Supply of
Pure Vaccine Lymph 12 Pall Mall East London S.W. do hereby declare the
nature of this invention to be as follows:-
The use of a valve or valves or the equivalent so placed that the water is made
to circulate in any desired direction. In order to make this more easily understood
suppose a tube is bent in the shape of an isosceles triangle A. B. C. the two open
ends communicating with a cistern at the apex A so that if water is placed in the
cistern it would be free to circulate in either directions A. B. C. A or A. C..B. A.
Now if the parts A. B. and A. C. are vertical and the part B. C. is horizontal and
heat applied to B. C. equally throughout its length it is clear that the water will
tend equally to circulate from C to A or from B to A and upon steam being
generated the water may be balanced in each leg and the part B. C. being left.
without water may be injured. But suppose a valve to be placed in the tube at C
opening towards B then the motion of the water towards C. A. will close the valve
and the circulation will be in the direction C. B. A and the impulse of the water
ejected from B. A. and the gravity of that in A. C. will both tend to recharge the
part C. B.
Dahin xth day of A...il 1905
Improvements in Water-tube Steam Generators or Water Heaters.
EDWARD THOMAS DARKE Secretary of The Association for the Supply of
Pure Vaccine Lymph 12 Pall Mall East London S. W. 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 the sectional drawing herewith A represents the apex of the isosceles.
triangle of which A. B. the one leg and A. C. the other lie in a vertical plane, the
base B. C. being horizontal to which figure the tube A" B. C¹ A' is supposed to be.
bent the open ends A" A terminating in a cistern or steam drum represented by
the circle ZA¹ A" the centre being at A. Now if the cistern or steam drum is
charged with water as represented, the tube being full and heat applied equally to
the tube B. C. it is clear that the water will tend to rise equally in each leg and
upon the generation of steam the water will be driven from the legs and all
circulation will be prevented but if a properly constructed valve be placed in the
horizontal tube B. C. near the bend Copening towards B as represented at V. the
motion of the contents of the tube V. c. A¹ in the direction V. c. A will close
the valve V. and the contents of the tube V. B. A" must be discharged wholly or in
part at A and the superior weight of the contents of the tube AC. V. together
with the impulse of the ejection will recharge the horizontal tube and so compel
the circulation in the direction A' C. B. A. From this description it will also
be clear 1st That a circulation may be set up and maintained in a tube led in the

page_text: direction of the broken line x. y. z. z in place of the leg B. A and hence it
follows that such valves may be used in water heaters in which the circulation is
set up by the generation of steam 2nd That the discharge may be under or over
the water level of the cistern or steam drum 3rd That one valve only would be
sufficient for two or more tubes when those tubes are so placed as to be heated
equally and in similar positions providing that the valve is placed in a supply or
downcast tube common to those tubes for example hollow fire bars or tubes used as
fire bars being beated equally and similar in position may be supplied from a
common pipe in which one valve would prove sufficient. 4th That under certain
circumstances an additional valve or valves may be placed to prevent the return of
the contents wholly or in part of the tube or group of tubes through which the
discharge passes.
5th That a natural circulation may be improved and the
priming and heating of the tubes prevented by the use of a valve or valves. Such
valves should be light or balanced so that they may be easily moved. I prefer
those commonly known as "flap valves the valve or flap hanging vertically
as shown and the box so placed and constructed as to be easy of access for
cleaning.
"
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 :-
The use of a valve or valves or their equivalents to compel circulation in any
desired direction or to assist the natural circulation in water tube and other boilers
and water heaters in which water tubes are used and in hollow fire bars as herein
before described.
Dated this Twenty-fourth day of January 1896.