Improvements relating to or connected with Clearance Spaces between Pistons and Cylinder Ends of Steam and other Elastic Fluid-pressure Engines
Year: 1897

page_text: Date of Application, 21st Dec., 1897
Complete Specification Left, 21st Sept., 1898-Accepted, 29th Oct., 1898
Improvements relating to or
connected with Clearance Spaces
between Pistons and Cylinder Ends of Steam and other Elastic
Fluid-pressure Engines.
I, JOSEPH EVANS, of Culwell Works, Heath Town, near Wolverhampton, in the
County of Stafford, Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention relates to clearance spaces between pistons and cylinder ends
of steam or other elastic fluid-pressure engines; and has for its object, in the
case of a vertical inverted cylinder engine, and more especially in the case of
an engine, such as a direct-acting pump, in which the downward movement of
the piston is stopped by a cushion of steam or other elastic fluid which is com-
pressed between itself and the end of the cylinder, to ensure that the water will
drain clear of a space within which the steam or other elastic fluid is trapped and
utilized as a cushion between the cylinder end and piston, and to ensure also
that water drained clear of such space will be readily forced, if pressed upon by
the piston, into the cylinder port as the piston completes its downward stroke;
and has for its object, in respect of steam and other elastic fluid-pressure engines
generally, to cut out from the main portion of the cushioning space between the
back of the piston and the cylinder end the recess into which the nut on the end
of the piston rod enters, to ensure that the steam or other elastic motor-fluid
within such main portion of such space will be more greatly compressed, for a
given travel of the piston after the escape of the steam or other elastic fluid has
been cut off, than would otherwise be the case, and the momentum of the moving
parts be consequently more satisfactorily cushioned; and the invention has the
further object, also, of providing a ready means of regulating the degree of
compression between the piston and bottom end of an inverted cylinder steam
or other elastic fluid-pressure engine in which the water is drained, according to
this invention, from a space within which the fluid is trapped to form the required
cushion, and comprises the application of such means, also, generally to the
purpose of regulating the degree of compression between a piston of a steam or
other elastic fluid-pressure engine and a cylinder end thereof.
In the case of a vertical inverted-cylinder pumping engine, or other vertical
inverted-cylinder engine, the piston is formed hollow at its underside, leaving an
annular portion which is of a thickness only which, is required to receive the
piston rings, and this hollow is bored to make it truly cylindrical inside. A
bung is formed at the upper side of the bottom end of the cylinder, for the depth,
or thereabouts, of the hollow of the piston, and is turned to be an easy or loose fit
within such hollow. An annular space is thus left between the interior wall of
the cylinder and the outside of the bung, into which any water in the cylinder will
drain. As the piston nears the bottom of its stroke the annular portion thereof

page_text: enters the annular space around the bung, and the steam or other fluid which is
thus trapped within the hollow of the piston forms a cushion against the momentum
of the piston. The annular portion of the piston passes preferably over, and closes,
the cylinder port somewhat before the piston reaches the end of the stroke, but
in such case a passage-way (or two or more of such) extends from such port to
the bottom of the annular space around the bung, and thus water which has
drained into such annular space is forced, if pressed upon by the annular portion
of the piston, into the port.
It is preferred to round off the upper corner of the bung and the lower corner
at the inner side of the annular portion of the piston, so that the bung may have
a lead into the hollow of the piston and any risk be avoided of the corners fouling
one another.
In the ease of steam or other elastic fluid-pressure engines generally, whether
vertical, horizontal or inclined, the space into which the nut on the back of the
piston rod enters, within the upper or back end of the cylinder, is formed with
a lower or inner portion which is bored out to make it truly cylindrical, and a
boss which is formed at the back of the piston is turned to be an easy sliding fit
within such bored portion of the recess. As the piston approaches the back end
of its stroke, this boss enters the bored portion of the recess in the upper or
back end of the cylinder, and closes the recess to the main space which is between
the upper or back side of the piston and the upper or back end of the cylinder,
and ensures, consequently, a greater degree of compression of the steam or other
elastic fluid which is within such space, for a given travel of the piston after the
escape of the motor-fluid has been cut off, than would otherwise be the case, with
the result, consequently, that the momentum of the moving parts is more satis-
factorily cushioned. It is preferred to round off the upper corner of the boss,
and also the corner of the bored portion of the recess, to give the boss a lead into
the recess, and avoid any risk of the corners fouling one another.
The means by which the degree of compression of the steam or other elastic
fluid within the trapped space, aforesaid, between the piston of an inverted
cylinder engine and the bottom of the cylinder, is regulated, consist of a bye-pass
passage, from such space into the annular space aforesaid, with a suitable appliance
by which the passage-way may be opened to any desired extent. This appliance
may conveniently consist of a screw which is screwed up through the bottom of
the cylinder and is formed at its inner end to screw up against a seat in the
passage-way, and the screw may be provided with a lock-nut to securely lock
it in any desired position. A similar arrangement of bye-pass, and means for
regulating the opening thereof, may be employed also generally for regulating the
compression between a piston of a steam or other elastic fluid-pressure engine and
a cylinder end thereof, the passage way in such case communicating between the
cushion and the cylinder port.
Doted this 20th day of Dacomb 180
STEPHEN WATKINS,
Wolverhampton, Agent for the Applicant.
CUALI LITE SPECIFICATION.
Improvements relating to or connected with Clearance Spaces
between Pistons and Cylinder Ends of Steam and other Elastic
Fluid-pressure Engines,
I, JOSEPH EVANS, of Culwell Works, Heath Town, near Wolverhampton, in the
County of Stafford, Engineer, do hereby declare the nature of this invention 5

page_text: and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
This invention relates to clearance spaces between pistons and cylinder ends
of steam or other elastic fluid-pressure engines, and has for its object, in the
case of a vertical inverted or other vertical cylinder engine, and more especially in the
case of an engine, such as a direct-acting pump, in which the downward movement of
the piston is stopped by a cushion of steam or other elastic fluid which is com-
pressed between itself and the end of the cylinder, to ensure that the water will
drain clear of a space within which the steam or other elastic fluid is trapped and
utilized as a cushion between the cylinder end and piston, and to ensure also
that wated drained clear of such space, will be readily forced, if pressed upon by
the piston, into the cylinder port as the piston completes its downward stroke;
and has for its object, in respect of steam and other elastic fluid-pressure engines
generally, to cut out from the main portion of the cushioning space between the
back of the piston and the cylinder end the recess into which the nut or cotter
of the piston rod enters, to ensure that the steam or other elastic motor-fluid
within such main portion of such space will be more greatly compressed, for a
given travel of the piston after the escape of the steam or other elastic fluid has
been cut off, than would otherwise be the case, and the momentum of the moving
parts be consequently more satisfactorily cushioned; and the invention has the
further object, also, of providing a ready means of regulating the degree of compres-
sion between the piston and bottom end of an inverted or other vertical cylinder
steam or other elastic fluid-pressure engine in which the water is drained, according to
this invention, from a space within which the fluid is trapped to form the required
cushion, and comprises the application of such means, also, generally to the
purpose of regulating the degree of compression between a piston of a steam or
other elastic fluid-pressure engine and a cylinder end thereof.
In order that the invention may be clearly understood, I will proceed to
describe the same with reference to the accompanying drawing, which though it
illustrates the cylinder and piston of a vertical inverted-cylinder pumping engine
will serve also to illustrate the application of the invention in the case of other
engines. Figure 1 is a vertical section taken through the centre of the cylinder
and through the steam chest, and Figure 2 is a vertical section of one side of the
lower end of the cylinder and the corresponding side of. the piston, the section
being taken at the point where the opening of the steam port into the cylinder
approaches most nearly to the end of the cylinder, that is to say, it is a section
taken through the back of the part shewn by Figure 1 in the plane indicated by
the liner.
In th case of a vertical inverted-cylinder or other vertical cylinder pumping
or other ngine, the piston A which works within the motor cylinder 13 is formed
hollow at its underside, leaving an annular part b which may be of such thickness
only as is required to receive the piston rings c, and the hollow a of the piston is
bored to make it truly cylindrical inside. A bung d projects from the upper
side of the bottom end D of the cylinder, and is of the depth, or thereabouts, of
the hollow a of the piston, and is turned to be an easy or loose fit within such
hollow. An annular space c is thus left between the interior wall of the cylinder
and the outside of the bung d into which any water in the cylinder will drain.
As the piston A nears the bottom of its stroke, the annular portion thereof
enters the annular space e around the bung d, and the steam or other fluid
which is thus trapped within the hollow a of the piston forms a cushion against
the momentum of the piston. The annular portion of the piston passes,
preferably, over, and closes, the cylinder port f somewhat before the piston reaches
the end of the stroke, but in such case a passage-way g, shewn by full lines in
Figure 2, but by dotted lines only in Figure 1, (or two or more of such) extends
from such port to the bottom of the annular space e, and water which has drained
into such annular space is forced, if pressed upon by the annular portion 6 of
the piston, into the port.

page_text: It is preferred to round off the upper corner of the bung d and the lower corner
at the inner side of the annular portion of the piston so that the bung may
have a lead into the hollow of the piston, and any risk be avoided of the corners
fouling one another.
In the case of steam or other elastic fluid-pressure engines generally, whether
vertical, horizontal or inclined, the space into which the nut F, or cotter, of
the piston rod G enters, within the upper, lower, or back end H of the cylinder,
as the case may be, is formed with a lower or inner portion which is bored out
to make it truly cylindrical, and a boss i which is formed at the back of the piston
is turned to be an easy sliding fit within such portion of the recess. As the
piston approaches the back end of its stroke, this boss i enters the portion of
the recess, and closes the recess to the main space which is between the upper
or back side of the piston and the upper or back end I of the cylinder, and
ensures, consequently, a greater degree of compression of the steam or other
elastic fluid which is within such space, for a given travel of the piston after the
escape of the motor-fluid has been cut off, than would otherwise be the case, with
the result, consequently, that the momentum of the moving parts is more satis-
factorily cushioned. It is preferred to round off the upper corner of the boss i, and
also the corner of the bored portion of the recess, to give the boss a lead into
the recess, and avoid any risk of the corners fouling one another.
When the back of the piston is the lower side thereof, in the case of a vertical
cylinder engine, the space into which the nut or cotter of the piston rod enters
in the bottom of the cylinder may be cut out from the cushioned space between
the piston and bottom of the cylinder, in addition to "adopting the means above
described by which the water is drained from such space, as will be readily
understood. When the recess for the nut or cotter is formed in the bottom of
the cylinder, it must of course have a suitable drainage opening.
The means by which the degree of compression of the steam or other elastic
fluid within the trapped space a, aforesaid, between the piston of an inverted or
other vertical cylinder engine and the bottom of the cylinder, is regulated, consist
of a bye-pass passage from such space into the annular space e, with a suitable
appliance by which the passage-way may be opened to any desired extent. This
appliance may conveniently consist of a screw 7 which is screwed up through the
boss m formed with the bottom of the cylinder, and is formed at its inner end
in a manner which permits of it being closed up against a seat formed in the
lower end of a vertical portion of the passage, and the screw may be provided
with a lock-nut to lock it in any desired position. The portion of the passage
is shewn to extend horizontally from the bottom of the vertical portion k into
the annular space e.
The form of bye-pass passage, and the means of regulating
the opening therethrough may, however, be varied, as will be obvious. sim
arrangement of bye-pass, and means for regulating the opening thereof, may be
employed also generally for regulating the compression between a piston of a
steam or other elastic fluid-pressure engine and a cylinder end thereof, the passage-
way communicating between the cushion and the cylinder port.
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. An inverted or other vertical cylinder of a steam or other elastic fluid-pressure
direct-acting or other pumping engine or other engine, having an annular recess,
such as e, in the lower end of the cylinder into which any liquid will drain, and
the piston formed with an annular portion, such as b, which as the piston nears
the bottom of its stroke enters within the annular recess, substantially as described.
2. An inverted or other vertical cylinder of a steam or other clastic fluid-
pressure direct-acting or other pumping engine or other engine, having an
annular recess, such as e, in the lower end of the cylinder into which any liquid
will drain, and the piston formed with an annular portion, such as b, which as

page_text: the piston nears the bottom of its stroke enters within the annular recess and
is a sliding fit around the inner wall thereof, substantially as described.
3. An inverted or other vertical cylinder of a steam or other elastic fluid-pressure
direct-acting or other pumping engine or other engine, having an annular recess,
such as e, in the lower end of the cylinder into which any liquid will drain, and
the piston formed with an annular portion, such as b, which as the piston nears the
bottom of its stroke enters within the annular recess and is a sliding fit around the
inner wall thereof, with means of communication between the lower portion of
such annular recess and the port through which the steam or other motor fluid is
brought into the corresponding end of the cylinder, substantially as described.
4. An inverted or other vertical cylinder of a steam or other elastic fluid-pressure
direct-acting or other pumping engine or other engine, in which the downward
movement of the piston is stopped or opposed by a cushion of steam or other
elastic fluid which is compressed between itself and the end of the cylinder, having
a part which projects upwards from the cylinder bottom and leaves an annular
space bounded by itself and the wall of the cylinder, and having the piston formed
with an annular portion which is just an easy fit around such upwardly pro-
jecting part and passes thereover as the piston approaches the bottom of its stroke
thus enclosing a cushion of steam or other elastic fluid within the hollow of the
piston which is surrounded by the annular portion thereof and is closed by the
upwardly projecting part of the cylinder bottom, substantially as described."
5. In a steam or other elastic fluid-pressure engine, a turned boss projecting at
the back of the piston, and surrounding the piston rod, a recess in the back end
of the cylinder formed with a bored portion to receive the boss of the piston as
an easy sliding fit therein, and with a portion which extends backwards from the
bored portion, to receive the nut, or cotter on the piston rod, substantially as
described for the purpose set forth.
6. The mears of regulating the degree of compression between the piston and a
cylinder end of a steam or other elastic fluid-pressure engine, which comprise the
use of a bye-pass passage from the cushion space between the piston and cylinder
end and the steam or other motor fluid port which is in communication with the
corresponding end of the cylinder, and means for regulating the opening of the
passage-way therethrough, substantially as described
7. The combination, with an inverted or other vertical cylinder steam or other
elastic fluid-pressure direct-acting or other pumping engine or other engine, of
an annular space formed in the lower end of the cylinder into which water is
drained, a bung formed with the cylinder bottom which enters a hollow space
formed in the underside of the piston and traps the steam or other motor fluid and
thereby opposes an elastic cushion to the downward movement of the piston, a
bye-pass passage which communicates with both the space containing the cushion
and the annular space in the lower end of the cylinder, and means for regulating
the opening of the passage-way through such bye-pass passage, substantially as
described.
73
odul .
1000