IMPROVEMENTS IN APPARATUS FOR INDICATING THE SPEED AND DIRECTION OF ROTATION OF ENGINE AND OTHER SHARTS.
Year: 1879

page_text: LETTERS PATENT to Beauchamp Tower, of No. 3, Grote's Place, Blackheath,
in the County of Kent, for the Invention of "IMPROVEMENTS IN APPARATUS
FOR INDICATING THE SPEED AND DIRECTION OF ROTATION OF ENGINE AND
OTHER SHARTS.
"
PROVISIONAL SPECIFICATION left by the said Beauchamp Tower at the
Office of the Commissioners of Patents on the 19th December 1879.
BEAUCHAMP TOWER, of No. 3, Grote's Place, Blackheath, in the County of Kent.
"IMPROVEMENTS IN APPARATUS FOR INDICATING THE SPEED AND DIRECTION OF
ROTATION OF ENGINE AND OTHER SHAFTS."
In many cases it is of advantage to be able to ascertain by inspection the
condition of an engine shaft or some other revolving shaft working at a distance
from the place of observation, as for example, on shipboard, where it is often
necessary for an officer to know the direction in which the engine shaft is at any
time rotating, and the speed of its rotation. My Invention relates to apparatus
for indicating either or both of these conditions, so that by simple inspection
of an instrument the velocity or the direction of rotation can be ascertained.
I will first describe the portion of the apparatus which serves for indicating
speed. For this purpose I provide a vessel divided into two compartments
which communicate with each other through a centrifugal pump driven from
the rotating shaft, the one compartment communicating with the centre of the
pump and the other with its circumference. These two compartments also
communicate with one another by a small passage at some height above the
pump. One of the compartments is open to the atmosphere, and the other
which is closed has a pipe extending from its upper part to a pressure gauge
at any place where the indication is required, or to a number of such gauges
at different places. The centrifugal pump and the two compartments are charged
with a liquid, preferably mercury, up to the level of the small passage by which
the compartments cominunicate. To one of the compartments, namely, that from
which the pipe leads, I supply air by a pump so as to maintain pressure in that
compartment, which pressure being communicated along the pipe is indicated on

page_text: the pressure gauges connected to it. When the shaft rotates in either direction the
centrifugal pump driven by it tends to raise the level of the liquid in the one
compartment and to lower it in the other, but the air pressure in the former
compartment acting on the surface of the liquid. keeps it at its level. This level is
automatically determined by the position of the small passage through which, when
the liquid is by excess of air pressure forced below it, the excess of air escapes.
Thus the air pressure in the pipe as indicated by the gauges is made to correspond
with the pressure of the liquid due to the action of the centrifugal pump. As this
pressure depends on the speed with which the pump is driven, the pressure gauges
indicate this speed, and consequently the speed of the shaft which drives the
centrifugal pump. The arrangement may be modified by inverting the connection
of the gauges to the compartments, the gauges then indicating the speed by
reduction of pressure, and in this case the air pump is arranged to exhaust instead
of to compress, and for it may be substituted a steam ejector or a communication
with the condenser of the engine. For indicating the direction in which the shaft
rotates I work from it an air pump having a cylinder oscillating on trunnions and
provided with ports arranged to be alternated by the oscillation of the cylinder in
such a manner that when the shaft rotates in the one direction the pump
compresses air, and when it rotates in the opposite direction the pump exhausts
air. A pipe connects the pump to one or more gauges which shew whether, the
pressure in the pipe is above or below that of the atmosphere, and consequently
whether the shaft is rotating in such direction as causes the pump to compress, or
in the opposite direction causing the pump to exhaust. This pump may be
employed to compress or exhaust the air in one of the compartments of the
apparatus above described for indicating speed, and when it is so applied, the pipe
connecting it with the said compartment is provided with suitable valves so
arranged that notwithstanding change of direction in the rotation of the shaft, the
pump always acts so as to compress in that compartment or to exhaust from it as
the case may be. The two gauges, namely, that indicating the speed and that
indicating the direction of rotation are conveniently arranged in one instrument, a
simple inspection of which shows at once the condition of the shaft as to velocity
and direction of rotation. In some cases, instead of employing two gauges as
above described, each with its connecting pipe, 1 employ a single pipe and gauge
shewing by increase of pressure the speed in the one direction of rotation and by
decrease of pressure the speed in the opposite direction. For working the apparatus
in this manner I provide at the centrifugal pump a rotating or other slide, which,
when the direction of rotation of the shaft is reversed reverses the communications
between the centrifugal pump and the two compartments, thus subjecting the
compartment which is connected to the gauges to an increase of pressure when the
shaft rotates in the one direction, and to a reduction of pressure when it rotates in
the opposite direction; or, instead of providing for reversal of the communications
to a centrifugal pump I employ a rotary pump of reversible kind, such as that
known as the helical pump.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Beauchamp Tower in the Great Seal Patent Office on the 18th
June 1880.
BEAUCHAMP TOWER, of No. 3, Grote's Place, Blackheath, in the County of Kent.
"IMPROVEMENTS IN APPARATUS FOR INDICATING THE SPEED AND DIRECTION OF
ROTATION OF ENGINE AND OTHER SHAFTS."
In many cases it is of advantage to be able to ascertain by inspection the
condition of an engine shaft or some other revolving shaft working at a distance
from the place of observation, as, for example, on shipboard, where it is often
necessary for an officer to know the direction in which the engine shaft is at any
time rotating and the speed of its rotation. My Invention relates to apparatus for
indicating either or both of these conditions, so that by simple inspection of an
instrument the velocity or the direction of rotation can be ascertained. I will first
describe the portion of the apparatus which serves for indicating speed. For this
purpose I provide a vessel divided into two compartments which communicate with
each other through a centrifugal pump driven from the rotating shaft, the one
compartment communicating with the centre of the pump and the other with its
circumference. These two compartments also communicate with one another by &
small passage at some height above the pump One of the compartments is open
to the atmosphere, and the other, which is closed, has a pipe extending from its
upper part to a pressure gauge at any place where the indication is required, or to
a number of such guages at different places. The centrifugal pump and the two
compartments are charged with a liquid, preferably mercury, up to the level of the
small passage by which the compartments communicate. To one of the compart-
ments, namely, that from which the pipe leads, I supply air by a pump so as to
maintain pressure in that compartment, which pressure being communicated along
the pipe is indicated on the pressure gauges connected to it. When the shaft
rotates in either direction the centrifugal pump driven by it tends to raise the level
of the liquid in the one compartment and to lower it in the other, but the air
pressure in the former compartment acting on the surface of the liquid keeps it at
its level. This level is automatically determined by the position of the small
passage through which, when the liquid is by excess of air pressure forced below it,
the excess of air escapes. Thus the air pressure in the pipe, as indicated by the
gauges, is made to correspond with the pressure of the liquid due to the action of
the centrifugal pump. As this pressure depends on the speed, with which the pump
is driven the pressure gauges indicate this speed and consequently the speed of the
shaft which drives the centrifugal pump. The arrangement may be modified by
inverting the connection of the guages to the compartments, the gauges then
indicating the speed by reduction of pressure, and in this case the air pump is
arranged to exhaust instead of to compress, and for it may be substituted a steam
ejector or a communication with the condenser of the engine. For indicating the
direction in which the shaft rotates I work from it an air pump having a cylinder
oscillating on trunnions, and provided with ports arranged to be alternated by the.
oscillation of the cylinder, in such a manner that when the shaft rotates in the one
direction the pump compresses air and when it rotates in the opposite direction the
pump exhausts air. A pipe connects the pump to one or more gauges which shew
whether the pressure in the pipe is above or below that of the atmosphere, and
consequently whether the shaft is rotating in such direction as causes the pump to
compress or in the opposite direction, causing the pump to exhaust. This pump may
be employed to compress or exhaust the air in one of the compartments of the apparatus
above described for indicating speed, and when it is so applied the pipe connecting
it with the said compartment is provided with suitable valves so arranged that

page_text: notwithstanding change of direction in the rotation of the shaft the pump always
acts so as to compress in that compartment or to exhaust from it, as the case may
be. The two guages, namely, that indicating the speed and that indicating the
direction of rotation, are conveniently arranged in ono instrument, a simple inspec-
tion of which shews at once the condition of the shaft as to velocity and direction
of rotation. In some cases instead of employing two guages, as above described,
each with its connecting pipe, I employ a single pipe and gauge shewing by
increase of pressure the speed in the one direction of rotation and by decrease of
pressure the speed in the opposite direction. For working the apparatus in this
manner I provide at the centrifugal pump a rotating or other slide which, when
the direction of rotation of the shaft is reversed, reverses the communications
between the centrifugal pump and the two compartments, thus subjecting the
compartiment which is connected to the gauges to an increase of pressure when the
shaft rotates in the one direction and to a reduction of pressure when it rotates in
the opposite direction. Or instead of providing for reversal of the communications
to a centrifugal pump I employ a rotary pump of reversible kind, such as that
known on the halient
•
Fig. 1 is a vertical section of apparatus according to my Invention for indicating
speed and direction of rotation; Fig 2 is an elevation partly in section of the
apparatus arranged to indicate speed only without regard to direction of rotation;
Fig. 3 is a transverse section to an enlarged scale through the reciprocating air
pump of Fig. 1, and its passages and valves. A is a spindle driven by gearing or
otherwise from the shaft whose speed and direction are to be indicated; it drives
by bevil gear the vertical spindle of a centrifugal pump B (which may be simply
a wheel with blades, as shewn in the plan Fig. 1a) working in mercury or other
heavy liquid; C and D are the two compartments of a vessel, the one C com-
municating with the central part of the pump case, and the other D with its
circumference. The compartment C is open to the atmosphere, but the com-
partment D communicates by a pipe with a pressure gunge E, or with several
Buch pressure guages. A small hole F forms a communication between the two
compartments C and D a little above their bottoms. The spindle A works by a
crank or eccentric a small air compressing pump, which may bo arranged as shewn
at G, Fig. when it is required to get an indication of speed only, but which is
differently arranged, as I will presently explain, when it is required to have an
indication of direction as well as of speed. For indicating speed of rotation the
action of the apparatus is as follows:-The centrifugal pump B by its rotation
tends to raise a column of liquid in the compartment D, but this column is kept
down to the level of the overflow orifice F by the pressure of air forced by the
pump G into the pipe communicating with D, the surplus air escaping by the
orifice F, through which also tho liquid column raised by the pump B overflows.
The pump must sustain in D a pressure equivalent to the pressure which the
column of liquid would develop if it rose to the height due to the velocity of
the pump B, and this pressure communicated to the guage E produces an indication
thereon corresponding with the speed of the pump B, and consequently of the shaft
which drives it. For convenience of reading the dial of the guage E instead of
being divided so as to indicate pressures is divided to indicate velocities, as for
example, numbers of revolutions per minute. For the purpose of indicating
direction of rotation without regard to speed, I employ an apparatus as shown
in Fig. 4.
In this apparatus the spindle H, the direction of whose rotation
is to be indicated, works by a crank or eccentric the piston of an air pump, the
cylinder K of which is mounted on trunnions L, so that it is caused to oscillate by
the action of the crank or eccentric. At the side of the cylinder K there are faces
against which it works, these faces having ports M communicating by a pipe with
a guage N containing a flexible diaphragm connected to an index after the manner

page_text: of an aneroid barometer. When the spindle H revolves in one direction the
opening of the ports M is so timed by the oscillation of the cylinder K that the
panip compresses air in the pipe, and the pressure acting on the diaphragm in N
forces it outwards, the index connected to it being thus moved in one direction so
as to point on a dial to a mark which may be "ahead." When the spindle H
revolves in the opposite direction the opening of the ports M is so timed that the
pump exhausts air, and the diaphragm in N is pressed inwards, moving the index
to a mark which may be "astern." The combined apparatus by which both speed
and direction are indicated is shewn in Figs. 1 and 3. In this case the pump
cylinder K, which oscillates on the trunnions L against a facing presenting ports M,
acts both as a forcing and as an exhausting pump, and the passages from the two
sets of ports are provided with check valves, as shewn in Fig. 3, so that whichever
way the spindle A revolves there is always compression of air in the passage O
leading to the compartment D of Fig. 1; but in the passage P their is either
compression or exhaustion of air according to the direction of rotation, as explained
with reference to Fig. 4. The latter passage P communicates by a pipe with a
guage, such as N, Fig. 4, shewing the direction of rotation. Instead of counter-
balancing the column of liquid acted on by the centrifugal pump by compressing
air into the compartment D which receives the discharge from the pump, it may be
counterbalanced by exhausting air from the compartment C which supplies the
pump, as shewn in the section Fig. 5, and elevation Fig. 6. In this case the
centrifugal pump B on the spindle A tends to lower the column of liquid in C; but
a steam ejector Q exhausts air from this compartment, and the reduction of
pressure shewing on the guage E indicates the speed of the pump, and conse-
quently of the shaft or wheel which drives it. By the arrangement shewn in
section at Fig. 7, and in elevation at Fig. 8, a single guage E is made to serve for
indicating both speed and direction according as its pointer is moved to the one
side or the other of the zero Z. In this case the spindle A works the oscillating air
pump K, which is arranged with ports M, as described with reference to Fig. 4,
so as to compress or exhaust according to the direction of rotation of the spindle A.
The centrifugal pump B is driven by sun and planet gear S, the planet wheel S
being mounted on an arm which is connected to a threeway cock R; this arm is
free to move between two fixed stops 8, 8. When the spindle A revolves in one
direction the arm of S is brought against one of the stops a, s³, and the cock R is
thereby turned into such a position that air is forced into the compartment D, and
the pressure of this air communicated by the pipe produces an indication on the
guage E, say, towards the right hand of the zero point, shewing the speed of
rotation in the one direction "ahead." When the spindle A revolves in the opposite
direction the arm of the planet wheel S is brought against the other of the
stops a, a¹, and the cock R is turned to such a position that air is exhausted.from
the compartment C. The reduction of pressure produces on the guage E an
indication of speed in the direction "astern."
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim,-
First. Indicating the speed of rotation of a shaft by a pressure guage subject
to the pressure of air forced into or exhausted from a pipe in opposition to the
increase or reduction of pressure produced in a heavy liquid by a centrifugal pump
driven by the rotating shaft, substantially as herein described.
Second. Indicating the direction of rotation of a shaft by a pressure guage
subject to the pressure of air which, by means of an oscillating pump worked
by the rotating shaft, is compressed or exhausted according as the shaft rotates
in the one direction or the other, substantially as herein described.
Third. The apparatus for indicating speed of rotation, herein described with
reference to Fig. 2 of the accompanying Drawings.
Fourth. The modified apparatus for indicating speed of rotation, herein described
with reference to Figs. 5 and 6.

page_text: Fifth. The apparatus for indicating direction of rotation, herein described with
reference to Fig. 4.
Sixth. The combined apparatus for indicating both speed and direction of rotation,
herein described with reference to Figs. 1, 1*, and 3.
Seventh. The modified apparatus for indicating both speed and direction of 5
rotation, herein described with reference to Figs. 8 and 9.
In witness whereof, I, the said Beauchamp Tower, have hereunto set my
hand and seal, this Eleventh day of June, in the year of our Lord One
thousand eight hundred and eighty.