Improvements in Apparatus and Appliances for Indicating and Registering the Mean Pressures of the Steam in Steam Engine Cylinders and the like.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Apparatus and Appliances for Indicating and
Registering the Mean Pressures of the Steam in Steam Engine
Cylinders and the like.
I, William RipPER, of 22, Wellesley Road, Sheffield, in the County of York,
Professor of Engineering, do hereby declare the nature of my said invention
to be as follows:-
My invention though applicable to various classes of steam engines is more
particularly applicable to high speed engines.
The primary object of my invention is to provide the means of recording on a
pressure gauge the mean effective pressure on the piston of an engine and to
record the same continuously if desired.
I carry out my invention in the following manner.
I provide two small barrels or cylinders in each of which are two ports opened
and closed as required by a valve which may have either a rotating or reciprocating
motion.
The barrels are each surrounded by a chamber to which is attached a pressure
gauge for recording the pressure in the chamber. The valves are arranged to
work so that the chamber surrounding one barrel is connected continuously with
the impulse side of the piston only, while the chamber surrounding the other
barrel is connected continuously with the exhaust side of the piston only.
The separation of the impulse stroke from the exhaust stroke in the two
chambers is obtained by arranging the passages leading from each end of the
engine cylinder so that each passage connects one end of one barrel of the indicator
with the opposite end of the other barrel.
The valves move simultaneously and are worked by an eccentric set 90° ahead
of the engine crank or by any other equivalent means.
The pressure in the respective chambers surrounding the barrels may be taken
by two separate gauges or by a single differential pressure gauge from which the
reading of the mean effective pressure in the engine cylinder may be read
directly.
In some cases I provide a registering apparatus so that a continuous record of
the pressures may be obtained during a given number of strokes or revolutions of
the engine, which number of strokes or revolutions may also be recorded by the
same or by a separate instrument.
100
R. HEBER RADFORD,
Agent for the Applicant.

page_text: Improvements in Apparatus and Appliances for Indicating and
Registering the Mean Pressures of the Steam in Steam Engine
Cylinders and the like.
I, WILLIAM RIPPER, of 22, Wellesley Road, Sheffield, in the County of York,
Professor of Engineering, do hereby declare the nature of my said 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 though applicable to various classes of steam engines is more
particularly applicable to high speed engines.
The primary object of my invention is to provide the means of recording on a
pressure gauge the mean effective pressure on the piston of an engine and to
record the same continuously if desired.
I carry out my invention in the following manner.
I provide two small barrels or cylinders in each of which are two ports opened
and closed as required by a valve which may have either a rotating or reciprocating
motion.
The barrels are each surrounded by a chamber to which is attached a pressure
gauge for recording the pressure in the chamber. The valves are arranged to
work so that the chamber surrounding one barrel is connected continuously with
the impulse side of the piston only, while the chamber surrounding the other
barrel is connected continuously with the exhaust side of the piston only.
The separation of the impulse stroke from the exhaust stroke in the two
chambers is obtained by arranging the passages leading from each end of the
engine cylinder so that each passage connects one end of one barrel of the indicator
with the opposite end of the other barrel.
The valves move simultaneously and are worked by an eccentric set 90 degrees
or thereabouts ahead of the engine crank or by any other equivalent means.
The pressure in the respective chambers surrounding the barrels may be taken
by two separate gauges or by a single differential pressure gauge from which the
reading of the mean effective pressure in the engine cylinder may be read
directly.
In some cases I provide a registering apparatus so that a continuous record of
the pressures may be obtained during a given number of strokes or revolutions of
the engine, which number of strokes or revolutions may also be recorded by the
same or by a separate instrument.
My invention will be better understood on reference to the accompanying
4 sheets of drawings in which the same letters refer to similar parts throughout
the several views.
Fig. 1, Sheet 1, represents one of my improved indicators in which I provide
two small barrels or cylinders, A, A, in each of which is a port or ports opened or
closed as required by a valve or valves, B, B, which valves move to and fro over
their respective ports. The barrels, A, A, are each connected by a pipe C, D¹,
with a pressure gauge, one barrel being connected to the gauge C, for indicating
the impulse or driving pressure of the steam acting on the engine piston; and
the other barrel with the pressure gauge, D, for indicating the back or exhaust
pressure acting on the engine piston. The reciprocating valves, B, B, are shewn
in mid-position and the engine piston is supposed to be at the end of its stroke;
say for example at the top. If the pipe, E, is connected with the top side of the
engine piston and the pipe, F, with the bottom side, then on the movement of

page_text: the said piston, the valves, B, B, move downwards opening the port and putting the
forward or impulse steam from the pipe, E, in communication with the pressure
gauge, C, whilst the exhaust steam from the pipe, F, is put into communication
with the pressure gauge, 1). On the reverse stroke when the engine piston is at
the bottom of its stroke the valves, B, B, will be again in mid-gear and on the
upward movement of the piston, the valves, B, B, rise, open their respective ports
and again turn the forward or impulse steam now coming from the pipe, F, into
the pressure gauge, C, and the backward pressure steam now coming from the
pipe, E, is turned into the pressure gauge, D, as shewn by the arrows. In this
arrangement the two valves, B, B, are connected to one common cross head, G,
and are driven by one small eccentric rod, H. The eccentric driving the valves
may be driven from the main engine shaft or from a countershaft on which it is
fixed 90 degrees or thereabouts ahead of the engine crank.
Fig. 2, Sheet 1, illustrates a similar arrangement to Fig. 1, but the valves, B, B,
are here driven by separate eccentrics placed opposite each other on the shaft.
The arrangements of the barrels and the ports being thus simplified.
Figs. 3, 4, 5, 6 & 7, Sheet 2, illustrate a modified form of my improved indicator,
the action of which is regulated by an oscillating valve, B, working in a single
barrel, A.
.
Fig. 3, shews the apparatus in transverse sections, the valve, B, being in mid-
position and the steam from both ends of the engine cylinder being thereby shut
off from the gauges. When the valve moves in the direction K to J, communica-
tion is opened between the top side of the engine piston from the pipe, E, to the
pressure gauge attached to the pipe, C', and at the same time communication is
opened between the bottom side of the engine piston from the pipe, F, to the gauge
attached to the pipe, D¹, conversely when the valve, B, oscillates in the direction J
to K the communication is reversed so that the pressure effect of the forward or
impulse steam is thereby always indicated on one and the same gauge, whilst
that of the backward or exhaust steam is always indicated on the other gauge.
Then the difference between the effects recorded by these two gauges will represent
the net mean pressure in the engine cylinder. Fig. 4, is a sectional elevation of the
apparatus, and, Fig. 5, is a plan.
Figs. 6 & 7, are a front and side elevation of the general arrangement of the
apparatus with its fittings and gauge or gauges as connected to the cylinder of
an engine.
Figs. 8, 9, 10, 11 & 12, Sheet 3, shew a further modified arrangement of my
improved apparatus in which the valve, B, is made to rotate on its axis. The steam
entering the barrel, cylinder or valve case, A, at E, & F, is directed, as before
explained, to one or other of the respective gauges connected to the pipes C¹ & D¹,
through openings, L, M, formed in the end flange of the valve.
Fig. 8, is a longitudinal section through the centre of the barrel, cylinder or
valve case A. Fig. 9, is a plan partly in section. Fig. 10, being a transverse
section taken on the line S, T, (Fig. 8). Fig. 11, being a transverse section on
the line X, Y, (Fig. 8), and, Fig. 12, a longitudinal section of the valve, B, shewing
the channels or passages leading to the pipes connected with the respective gauges.
Fig. 13, Sheet 4, shews an arrangement by which my improved apparatus may
be divided into two parts for use with long stroked engines in which the oscillating
valve is used as in Fig. 3, Sheet 2, but modified for use when the instrument is
divided as shewn. The object in view in this design is to open the ports suc-
cessively during a half revolution of the crank to the two gauges, C & D), for
recording forward and backward pressure respectively. Also that the pressure
cting upon the water in the pipe at one end is opposed by the metallic surface of
the valve which closes the port at the other end thereby preventing oscillation
of the water in the pipes and transmitting the pressure without loss to the
gauges.
Fies 14 & 15 Shoot 4 are trenavarca cations o
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page_text: 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:
1. In a mean pressure indicator the arrangement and combination of parts and
appliances by means of which a valve or valves move over ports in such a manner
that the pressure of the steam driving the engine piston is communicated directly
and continuously to one pressure gauge, while the pressure resisting the piston is
communicated directly and continuously to another pressure gauge, the two effects
always being kept separate and distinct in the manner and for the purposes
substantially as herein described and illustrated.
2. In a mean pressure indicator as described in Claim 1, the arrangement and
combination of parts and appliances by means of which, at or before the beginning
of the stroke of the engine piston, the valve or valves of the instrument open
communication between the two opposite ends of the cylinder and the pressure
gauges, and maintain the communication open in each case during a half revolu-
tion of the engine, the forward and backward pressure steam being directed into
the forward and backward pressure gauges respectively, and in like manner during
the other half revolution, and in the reverse stroke of the engine by the movement
of the valve or valves of the instrument the forward and backward
pressure steam
is directed into the forward and backward pressure gauges respectively in the
manner and for the purposes substantially as herein described and illustrated.
3. The construction of a mean pressure indicator as described in the foregoing
Claims 1 & 2 by means of which the reading of the mean effective pressure in an
engine cylinder on a time basis may be ascertained by taking the difference
between the readings of the two gauges as described in Claim 1, in the manner
and for the purposes substantially as herein described and illustrated.
Dated this 14th day of May 1898.
R. HEBER RADFORD,
Agent for the Applicant.