An Improved Form of Instrument for Automatically Recording Pressure or Vacuum of Gaseous Bodies contained in Closed Vessels.
Year: 1893

page_text: Date of Application, 14th Oct., 1893-Accepted, 18th Nov., 1893
COMPLETE SPECIFICATION.
An Improved Form of Instrument for Automatically Recording
Pressure or Vacuum of Gaseous Bodies contained in Closed
Vessels.
I WILLIAM REGINALD CHESTER, Civil Engineer of The Woodlands,
Mapperley Hill, Nottingham in the County of Nottingham, 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 :-
The instrument is shewn in elevation on the accompanying plan inside the case
which is shown in section and consists of :-
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A lever "a" of the third kind which has an adjustable counterbalance
weight "a¹
at the extreme end and is attached to the forked head of a vertical
column "d" by a turned pin "a" which acts as fulcrum the intermediate portion
of the lever is attached by means of a forked rod "c" to a float "c" which rises
or falls with the liquid in the vessel "6" caused by any variation in the pressure
or vacuum of the gaseous body. The other end of the lever has an ink pen or
pencil "e
attached to it which as the lever rises or falls marks on the paper
diagram fixed on the clockwork cylinder "f." The forked head to which the
lever is attached by the turned pin "a" is pivotted on the top of the column "d”
so that it may move in a horizontal direction away from the diagram. In this way
the pen or pencil can be thrown out of contact with the diagram at will: a small
adjustment screw "a" is attached to the forked head of the column which is set
so as to allow the pen or pencil to be brought into sufficient contact with the
diagram and no more.
"
A liquid vessel "6" formed of an inner cylinder "1" open at the top and
communicating at the bottom with the outer cylinder "62" which is hermetically
closed at the top except at the point where the gas enters above the surface of the
liquid by the pipe "g." In the inner cylinder is a float "c" which may be made
of any light substance having buoyancy in the liquid used. When the pressure of
the gas acts upon the surface of the liquid in the outer cylinder the liquid is
depressed in this cylinder and rises in the inner cylinder "6" thereby raising the
Hoat "c" which in its turn raises the lever ", a and causes the pen or pencil to
mark the variation on the paper diagram. The converse of course takes place
when the pressure is decreased. The areas of the two cylinders may be in any
proportion to each other according to the range of pressure or vacuum to be
recorded but for convenience I make them so that the annulus in the outer cylinder
is as near as may be twice the area of the inner cylinder so that for every inch of
variation in the height of the liquid in the outer cylinder there will be a rise or
fall of double the extent in the height of the liquid in the inner cylinder.
A cylinder "f" on which the diagram paper is fixed actuated by clockwork
placed in the interior and which is made to revolve thereby, is fixed on a vertical
column "f1"
An ordinary shaped glass pressure gauge "h" is attached to the supply pipe
and to the top of the outer cylinder by the pipe "g" for the purpose of comparing
the recorded pressures with those indicated on the gauge at any particular
moment.
At the bottom of the liquid vessel "6" are placed two plugs ";" and "j"-the
plug "i" is for emptying the cylinder of the liquid and the plug "j" is for drawing
off any condensate which may separate itself from the gas.
The whole instrument is enclosed in a wood case "k" having glass panels and
may be either portable or fixed at will.

page_text: 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 combination and arrangement of an improved form of instrument for
automatically recording pressure or vacuum of gaseous bodies in closed vessels.
Dated this 9th day of October 1893.
WILLIAM REGINALD CHESTER.