or other Description of Pumps.
Year: 1885

page_text: or other Description of Pumps.
I, JOHN HIRST MITCHELL of Bank End, Brockholes, near Huddersfield
Yorkshire, Engineer and Millwright do hereby declare the nature of my
invention for IMPROVEMENTS IN PISTONS OF STEAM ENGINES, AND HYDRAULIC,
AIR, OR OTHER DESCRIPTION OF PUMPS to be as follows:-
"
:-
This invention has reference to the pistons of steam engines, and also to the
pistons of Hydraulic, Air, or other description of pump, and the object of my
invention is to provide a simple and effective means for expanding the metallic
rings of the piston, so that the steam cannot pass between the piston and the
cylinder.
In order to carry out my invention I employ two metallic rings, accurately
turned both on the inner and outer sides and fitted between the flange and the lid
of the piston block; these rings are each cut through in one place to allow of
expansion and compression.
Between the inner circumference of the metallic rings and the neck of the piston
block I insert another metallic ring or spring equal in depth to the two outer rings.
A part of the circumference of the inner ring is cut away so that when the ring is
fixed into its place the part cut away leaves a space into which I insert a strong
steel spring, which forces out or expands the inner and outer rings, causing the
periphery thereof to bind tightly against and correctly fit the inside of the
cylinder.
When the steel spring has lost its elasticity and fails to expand the rings, a thin
key may be inserted between the said spring and the edge of the spring ring, by
which means the steel spring is again rendered serviceable.
By the method above described, the proper expansion of the metallic rings is
effected in a simple and effective manner, and the waste of steam by escaping
between the piston and the inner circumference of the cylinder is prevented.

page_text: Improvements in Pistons of Steam Engines, and Hyaraune, Air,
or other Description of Pumps.
"
I, JOHN HIRST MITCHELL of Bank-end Brockholes, near Huddersfield
Yorkshire, Engineer and Millwright do hereby declare the nature of my
invention for IMPROVEMENTS IN PISTONS OF STEAM ENGINES, AND HYDRAULIC,
AIR, OR OTHER DESCRIPTION OF PUMPS" and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
This invention has reference to the pistons of steam engines, and also to the
pistons of hydraulic, air, or other description of pump, and the object of my
invention is to provide a simple and effective means for expanding the metallic
rings of the piston so that the steam cannot pass between the piston and the
cylinder.
In order to carry out my invention I employ two metal rings, accurately turned
both on the inner and outer sides and fitted between the flange and the lid of the
piston block; these rings are each cut through in one place to allow of expansion
and compression.
Between the inner circumference of the metallic rings and the neck of the piston
block I insert another metallic ring or spring equal in depth to the two outer rings.
A part of the circumference of the inner ring is cut away, so that when the ring is
fixed into its place the part cut away leaves a space into which I insert a strong
steel spring, which forces out or expands the inner and outer rings, causing the
periphery thereof to bind tightly against and correctly fit the inside of the
cylinder.
In order that my invention may be more fully understood I herein make
reference to the accompanying sheet of drawings illustrative thereof.
Fig. 1 is elevation of a piston with my improvements added thereto; Fig. 2 is
cross section of same, and Fig. 3 is plan view with the lid or cover of the piston
removed. A is the piston rod connected in the ordinary manner to the piston
block B, and C is the lid or cover which is secured to the piston block by the
bolts a.
Between the lid or cover C and the flange b of the piston block are fitted
two metallic rings D placed one above the other, each ring being cut through in
one place c to allow of expansion and compression.
An annular recess d is formed in the two rings D in which are placed a number
of flat springs e for the purpose of keeping the two rings close against the cover C
and flange b.
In order to make the piston steam tight another metallic ring E is employed,
equal in depth to the two rings D, which ring E is inserted between the inner
circumference of the rings D and the neck of the piston block. A part of the
circumference of the said ring E is cut away as shewn in plan view Fig. 3, so that
when the said ring is fitted in its place, a small space or opening is left into which
is forced a strong steel spring F strong enough to expand the metallic ring E and
also the two outer rings D until the peripherys of the two rings D bind tightly
against and correctly fit the inside of the cylinder.

page_text: When the rings have become worn by constant friction and the spring has lost
its expansive pressure, a thin key may be inserted on one or both sides of the steel
spring F which will again renew its. elasticity and preserve the piston from
leakage."
CC
By the method above described, the metallic rings of the piston are expanded in
a simple and effective manner, and the waste of steam by escaping between the
piston and the inner circumference of the cylinder is prevented. The rings and
spring are of the simplest construction and cannot get out of order, they are
durable, steamtight, and work with the least possible friction; they can also be
fitted to any ordinary pistons whether of steam engines or of hydraulic, air, or
other description of pumps.
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
The combination with the metallic rings D and E of the steel spring F applied
substantially in the manner herein shewn and described, or a mere modification
thereof.