Year: 1894

page_text: Date of Application, 1st Jan., 1894
Complete Specification Left, 1st Oct., 1894-Accepted, 10th Nov., 1894
I, THOMAS CAINK of Woodland View London Road in the City of Worcester
City Engineer's Assistant do hereby declare the nature of this invention to be as
follows:-
:-
The usual forms of gauges for indicating at a distance the height of water in
reservoirs are
(1) Gauges which have their indications transmitted by electric currents
operated by means of a float which rises and falls with the water in the reservoir.
(2) Gauges which have their indications transmitted by means of a column of
water in a pipe, the pressure and therefore the height of the column being
measured by a counterbalancing column of mercury or other means.
(3) Gauges which have their indications transmitted by means of air enclosed in
a tube. A bell with its open end downwards is usually placed at the bottom of the
reservoir and from the top of the bell a tube rises above the surface of the water
and is carried to a counterbalancing column of mercury or other gauge where the
indications are required.
In the method number 2 the column of mercury must have a height corre-
sponding to the total difference of level between the gauge and the level of the
water in the reservoir and a strength of pipe from the reservoir to the gauge
In the method
sufficient to resist the pressure of such a column of water.
number 3, the length of the column of mercury in the gauge need only correspond
to the height and pressure of water in the reservoir itself and the strength of the
air pipe between the reservoir and gauge only such as to resist that pressure. Such
a method of transmitting the indications of the height of water in a reservoir
cannot however be adopted for distances exceeding a few hundred yards, owing to
the compression of the air in the tube allowing an appreciable rise of water up the
Variations
same and consequently indicating a smaller depth than there really is.
of temperature also seriously affect the indications.
The advantages and economy of such a method if the objections to it to which I
have referred were removed are sufficiently obvious, and it is an invention of means
for their removal that forms the subject of this application for a Patent to be
granted to me.
The means consist in pumping air into the tube which transmits the pressure of
water in the reservoir to the gauge. It is convenient but not essential to use a
small water or other motor for that purpose and to keep it constantly working at a
conveniently slow rate. Or the pump may be set working for a short time when
indications require to be taken.
The effect of thus pumping air into the transmitting tube is to drive out any
water that may have risen in the tube from either of the causes which I have
mentioned or from any other cause, and so keep the tube fully charged with air
and thus the exact pressure and height of the water in the reservoir is communicated
to the gauge, any excess of air which may be pumped in escaping in bubbles from
under the bell in the reservoir.
It is desirable to prevent the possibility of water from condensing in the air pipe
as any accumulation therein may vitiate the indications. This may be done by
drawing the air through any hygrometric substance before passing it into the pipe
such as strong sulphuric acid, calcium chloride &c., but the method which I prefer,
is to pump the air into a strong closed vessel subjecting it to a greater pressure than
that which it can receive in the air pipe and, after allowing it to cool either by the

page_text: exhaust water from the motor falling upon the vessel or other means, discharging
it into the transmission pipe through a very small orifice either intermittently or
continuously.
The subjection of the air to the increased pressure will raise its temperature, and
upon cooling, the moisture which the air contains will be condensed in the vessel
and may be removed by a cock provided for the purpose.
Dated this Thirtieth day of December 1893.
COMPLETE SPECIFICATION.
Improvements in Reservoir Gauges.
I THOMAS CAINK of Woodland View London Road in the City of Worcester
Civil 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 :-
This improvement consists in a device whereby the pressure due to the height of
water contained in a reservoir or other receptacle may be transmitted to any
distance pneumatically and there indicated by a gauge or other means without
being affected by variations of temperature or barometric pressure, by compression
or absorption, and whereby condensation of moisture within the pneumatic tube is
prevented. The essential features of the contrivance are shewn on the drawings
hereto annexed in which in Fig. 1A is a reservoir B an air pipe having its lower
end open and its upper end connected with the pneumatic tube C which com-
municates with the gauge shewn on Figures 2 and 3 in which D is a mercury or
other gauge communicating with the pneumatic tube C, E is a water or other
motor driving an air pump F having its outlet communicating by means of tube G
with cooler or condenser H, at the lower end of which is a drain cock J. K is the
supply pipe to motor, L is the exhaust, M is a pressure gauge for indicating the
pressure of air in condenser, N is a cock which transmits through a small orifice
the air from condenser to pneumatic tube and gauge D.
The action is as follows:-The water in reservoir compresses the air within the
tube B which transmits the pressure to mercury in tube D whereby the column of
mercury is lifted until its weight equals and balances the pressure yielded by the
water in reservoir thereby indicating the height thereof. The weight of water in
reservoir would by compressing the air in tube diminish its volume and the water
would rise in tube B and as the mercury would only indicate the difference of level
between the water within the tube B and that in the reservoir the true height of
the water in reservoir would not be shewn. To overcome this the motor E is
employed to slowly pump air into the tube B by means of air pump F, the tube is
thereby kept constantly fully charged any excess escaping below the bottom in
bubbles in reservoir, the same means compensates for any reduction in volume of air
that may be due to any other cause.
In a long length of tube it is probable that some parts may be lower than others,
into which lower parts any water which may condense in the tube would collect
and prevent the correct transmission by the air of the pressure of water in reservoir.
To prevent that, the air is first pumped at a high pressure into a strong receiver H
which raises its temperature but which is again lowered by radiation from the
surface of the receiver or cooler and also by the exhaust water from pump falling
upon it.
The air then escapes in a dry condition through a small orifice in cock N
from cooler.
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. The employment of means whereby the pressure due to the water or other

page_text: liquid in a reservoir or other receptacle may be transmitted to any distance
pneumatically and there indicated by a gauge or other means, without being
affected by variations of temperature of the air within the pneumatic tube or
barometric pressure or by compression or absorption and whereby condensation is
prevented.
2. The employment in conjunction with reservoir gauges of an air pump driven
either by water or other motor or by hand for the purpose of keeping the air tube
fully charged between the outlet or inverted bell in reservoir and the gauge
substantially as described.
3. The employment of the operation of air compression for the purpose of
intercepting moisture in a receptacle so as to prevent the condensation thereof
within a pneumatic tube.
Dated this 29th day of September 1894.
THOMAS CAINK.