Improvements in Hydraulic or Liquid Brakes for Causing and Measuring Resistance on Rotating Shafts.
Year: 1887

page_text: Date of Application, 28th July, 1887
Complete Left; 28th Apr., 1888
Complete Accepted, 1st June, 1888
Improvements in Hydraulic or Liquid Brakes for Causing and
Measuring Resistance on Rotating Shafts.
I OSBORNE REYNOLDS of the Owens College Manchester in the County of Lancaster
Professor of Engineering do hereby declare the nature of said Invention for
IMPROVEMENTS IN HYDRAULIC OR LIQUID BRAKES FOR CAUSING AND
RESISTANCE ON ROTATING SHAFTS to be as follows:-
-
MEASURING
My invention relates to improvements in hydraulic or liquid brakes for causing and
measuring resistance on rotating shafts.
The class of brakes to which my Invention is applicable are those which consist of
a revolving wheel enclosed in an outer casing containing water or other liquid. This
wheel is provided with vanes which impart a rotational motion to the water within the
wheel and the casing bas passages or guides which destroy or reverse the direction of
the motion of rotation in the water passing from between the vanes in the wheel into
the passages or spaces between the guides in the casing so that the water which passes
from the spaces between the guides in the casing into the spaces between the vanes in
the wheel enters without rotation or with rotation opposite to that of the wheel
opposing by its inertia the motion of the wheel while it receives fresh rotation in the
same direction as that of the wheel.
My improvements consist chiefly in the application and arrangement of certain
passages which I severally designate air passages supply passages and exit passages
which passages are provided with valves by means of which the quantity of air and
liquid in the brake are controlled while at the same time a continuous current
of liquid through the brake is secured. The air passages are formed in the material
of the casing and guides or part in this way and part by pipes they lead from
the interior of the brake near those parts at which when the brake is full and rotating
the pressure in the liquid is least into open air.
The supply passages lead from any convenient source or reservoir of liquid which
will supply the liquid to the brake without suction through the casing to an interior
chamber adjacent to the wheel or equivalent revolving portion of the brake as near as

page_text: convenient to the axis of rotation thence by means of ducts in the material of the
wheel and vanes or partly by pipes to the interior of the brake near those parts at
which the pressure is least when the brake is full of liquid and revolving.
The exit passages lead from that part of the interior of the brake where when full
of liquid and revolving the pressure in the brake is greatest through the casing into
any convenient waste or escape passage. In these passages are suitable stop or
regulating valves by which they are severally controlled as previously stated.
The action of these passages is as follows:-When the brake is revolving being
empty of liquid and all the passages being open the pressure on the supply of water
or other liquid causes it to enter those parts of the passages which are within the
wheel in these the centrifugal force due to the revolution of the wheel together with
any pressure there may be in the supply tends to cause the water to enter the brake
driving out the air through the open air passages. Having once entered the brake
the liquid will at once proceed to leave it again by the exit passage and if the aperture
be sufficiently large the liquid will leave as fast as it enters without making any
accumulation in the brake or causing.any considerable resistance to the rotation of the
shaft but when the exit passage restricted by partially closing the valve the quantity
of liquid which escapes is less than that which enters so that the liquid accumulates in
the brake expelling and discharging the air through the air passages. As the liquid
in the brake increases its centrifugal force increases the pressure on the exit without
affecting the supply the pressure on which is determined by the pressure of the air so
that with a nice or particular adjustment of the supply and exit valves the liquid will
accumulate in the brake until the discharge equals the supply at which point it will
remain constant thereby causing a constant resistance so long as the speed of rotation
is constant. Further closing the exit or opening the supply will cause the resistance
of the liquid in the brake to increase until this again becomes constant so that as long
as the air passage is open these valves afford a complete means of adjusting and
controlling the resistance from the least resistance with the brake empty to the
greatest resistance with the brake full.
When the brake is running at a constant speed with any particular adjustment of
the supply and exit valves the work spent in overcoming the resistance of the liquid
is spent in heating the liquid. The heat thus generated may be carried away by the
steady stream of water through the brake without causing any considerable rise
of temperature or by restricting this stream the temperature may be made to rise until
the liquid boils when the vapour or steam passes away through the air passages
without causing any considerable increase of pressure within the brake while
the liquid that is evaporated is continually replaced from the supply. By measuring
the quantity of liquid which leaves the brake and the amount by which its temperature
is raised the amount of heat generated within the brake is ascertained and this is the
heat equivalent of the work that has been spent in overcoming the resistance of the
brake of which it therefore affords a measure.
For measuring the resistance imposed on the shaft. I adopt the usual method. The
casing is so adjusted as to exactly balance on the shaft when solely supported by this
then by means of suitable levers weight or springs the forces necessary to keep the
case from rotating with the shaft are exactly measured and these are exactly equal to
the resistance imposed by the case on the wheel by means of the fluid within.
Datad this 27th dov of July 1807

page_text: Improvements in Hydraulic or Liquid Brakes for Causing and
Measuring Resistance on Rotating Shafts.
1 OSBORNE REYNOLDS of the Owens College Manchester in the County of
Lancaster Professor of Engineering, 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 :-
My invention relates to improvements in hydraulic or liquid brakes for causing
and measuring resistance on rotating shafts.
The class of brakes to which my Invention is applicable are those which consist
of a revolving wheel enclosed in an outer casing containing water or other liquid.
This wheel is provided with vanes which impart a rotational motion to the water
within the wheel and the casing has passages or guides which destroy or reverse
the direction of the motion of rotation in the water passing from between the vanes
in the wheel into the passages or spaces between the guides in the casing so that the
water which passes from the spaces between the guides and the casing into the
spaces between the vanes in the wheel enters without rotation or with rotation
opposite to that of the wheel opposing by its inertia the motion of the wheel while it
receives fresh rotation in the same direction as that of the wheel.
My improvements consist chiefly in the application and arrangement of certain
passages which I severally designate air passages supply passages and exit passages
which passages are provided with valves by means of which the quantity of air and
liquid in the brake are controlled while at the same time a continuous current of
liquid through the brake is secured. The air passages are formed in the material of
the casing and guides or part in this way and part by pipes they lead from the
interior of the brake near those parts at which when the brake is full and rotating
the pressure in the liquid is least, into open air.
The supply passages lead from any convenient source or reservoir of liquid which
will supply the liquid to the brake without suction through the casing to an
interior chamber adjacent to the wheel or equivalent revolving portion of the
brake as near as convenient to the axis of rotation thence by means of ducts
in the material of the wheel and vanes or partly by pipes to the interior
of the brake near those parts at which the pressure is least when the brake is
full of liquid and revolving.
The exit passages lead from that part of the interior of the brake where when full
of liquid and revolving the pressure in the brake is greatest through the casing into
any convenient waste or escape passage. In these passages are suitable stop or
regulating valves by which they are severally controlled as previously stated.
The action of these passages is as follows:-When the brake is revolving being
empty of liquid and all the passages being open the pressure on the supply of water
or other liquid causes it to enter those parts of the passages which are within the
wheel; in these the centrifugal force due to the revolution of the wheel together
with any pressure there may be in the supply tends to cause the water to enter the

page_text: brake driving out the air through the open air passages. Having once entered the
brake the liquid will at once proceed to leave it again by the exit passage and if the
aperture be sufficiently large the liquid will leave as fast as it enters without making
any accumulation in the brake or causing any considerable resistance to the rotation
of the shaft but when the exit passage is restricted by partially closing the valve the
quantity of liquid which escapes is less than that which enters so that the liquid
accumulates in the brake expelling and discharging the air through the air passages.
As the liquid in the brake increases its centrifugal force increases the pressure on the
exit without affecting the supply the pressure on which is determined by the pressure
of the air so that with a nice or particular adjustment of the supply and exit valves
the liquid will accumulate in the brake until the discharge equals the supply at which
point it will remain constant thereby causing a constant resistance so long as the speed
of rotation is constant. Further closing the exit or opening the supply will cause the
resistance of the liquid in the brake to increase until this again becomes constant so
that as long as the air passage is open these valves afford a complete means of
adjusting and controlling the resistance from the least resistance with the brake empty
to the greatest resistance with the brake full.
When the brake is running at a constant speed with any particular adjustment of
the supply and exit valves the work spent in overcoming the resistance of the liquid
is spent in heating the liquid. The heat thus generated may be carried away by the
steady stream of water through the brake without causing any considerable rise of
temperature or by restricting this stream the temperature may be made to rise until
the liquid boils when the vapour or steam passes away through the air passages
without causing any considerable increase of pressure within the brake while the
liquid that is evaporated is continually replaced from the supply. By measuring the
quantity of liquid which leaves the brake and the amount by which its temperature
is raised the amount of heat generated within the brake is ascertained and this is the
heat equivalent of the work that has been spent in overcoming the resistance of the
brake of which it therefore affords a measure.
For measuring the resistance imposed on the shaft I adopt the usual method. The
casing is so adjusted as to exactly balance on the shaft when solely supported by
this then by means of suitable levers weights or springs the forces necessary to keep
the case from rotating with the shaft are exactly measured and these are exactly
equal to the resistance imposed by the case on the wheel by means of the fluid
within.
And in order that my Invention may be fully understood and readily carried into
effect I will describe the accompanying four sheets of Drawings reference being had
to the figures and letters marked thereon.
Figure 1 is a side elevation Fig. 2 an end view Fig. 3 a side sectional elevation and
Fig. 4 a transverse vertical section of a hydraulic or liquid brake embodying my
improvements and Figs. 5 to 8 are views of some of the parts of the apparatus.
In these views. a designates the spindle or shaft on which the liquid brake
is mounted this shaft is free to revolve in suitable bearings and is coned or tapered in
two places and on these coned surfaces are fitted two correspondingly tapered sleeves
or bushes 66. On these bushes are mounted the sides of the outer casing which
is made up of two flanged discs c c' each of which is secured by bolts d to a ring e
which forms the periphery of the casing.
I
The surface of that part of the shaft which lies between the two coned portions is
left plain and on it is fixed by set screws f, see Fig. 3, or other means a wheel made
up of two separate discs secured together by bolts h. The discs which compose the
outer casing and the inner wheel are so constructed and arranged that when in their
respective positions on the shaft a two chambers or passages ii are formed between
the sides of the two wheels each of which passages is oval in cross section and is
concentric with the shaft a and there are also two separate chambers or passages
concentric with the shaft one passage ; near the ring e and the other k nearer the
shaft. The oval passages ii are fitted with a number of vanes or guides consisting of
semicircular discs and m of which the vanes are secured to or formed with the

page_text: outer casing and the vanes m are formed with or secured to the inner wheel g;
these vanes are set parallel to one another and at an angle say of forty five degrees
to the axis of the shaft the straight edges of the semicircular vanes secured in the
outer casing just clearing the straight edges of those secured in the inner wheel.
On the exterior of the outer casing is formed a water chamber n which is connected
by a flexible tube n¹ to a water supply pipe n² controlled by a valve n³ and a stop
cock n to regulate the admission of water under pressure to the brake. The water
admitted to the chamber is free to flow into an annular recess o and thence through
openings o into the inner chamber which is provided with a number of ports k¹
leading into ducts or passages m¹ one of which is formed in each vane m secured to
the inner wheel g. Each of the vanes secured to the outer casing has a similar duct
or passage communicating with an annular recess p leading by a passage pl to a
chamber p² formed in the ring e which chamber p² has an outlet p³ communicating
with the atmosphere by a pipe pt. The oval passages i have ports leading into
i
the chamber which has an outlet j' connected to a waste. pipe j2 controlled by a
valve The inlet valve n³ and the outlet valve may either be operated separately
or may be coupled by the arrangement of links and levers and operated simul-
taneously by the screw s or the link may be pivoted to any convenient stationary
piece in such manner that any movement of the brake on its axis will automatically
open or close both valves ³ ³ simultaneously and so regulate the admission and
discharge of liquid. An arm or levert which supports adjustable weights u to
measure or indicate the motive power given off by the rotating shaft is secured to the
outer casing on the other side of which is secured a counterpoising weight v under
which is a standard to prevent the casing being turned over. There is also
mounted adjustably on the arm & an adjustable weight w which can be moved along
the arm t by a screw or other means, not shown, and under the case is a standard wi
to prevent its descending further than is convenient.
When the shaft a has been coupled to the shaft of the engine the latter may be
started and as the inner wheel revolves with the brake empty and all the passages
open the centrifugal force due to the revolution of the wheel together with the
pressure on the water admitted to the chamber n causes the water to enter those parts
of the passages which are within the wheel thereby driving out the air through the
passages 11 Pp p² into the atmosphere through the outlet på and pipe p. The
centrifugal force due to the revolution of the inner wheel drives the water
towards the periphery of the wheel and thus the greater pressure near the outer
side of the oval passages ii causes the water to circulate in the spaces between the
vanes and to flow at the point where the pressure is greatest through the ports i¹
into the passage j whence it escapes through the outlet j and waste pipe j².
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. The construction use and application of the air passages supply passages and
exit passages arranged and operating substantially as and for the purposes herein
described with reference to the Drawings annexed.
2. The several constructions combinations and arrangements of parts embodying
my improvements in hydraulic or liquid brakes for causing and measuring resistance
on rotating shafts substantially as herein described and as illustrated by the
Drawings.