IMPROVED VALVES FOR AIR JAMES FORREST of the same placeer, COMPRESSORS
Year: 1882

page_text: LETTERS PATENT to Charles Pilkington of Haydock in the County of
Lancaster Engineer and James Forrest of the same place Engineer for an
PROVISIONAL SPECIFICATION left by the said Charles Pilkington and
James Forrest at the Office of the Commissioners of Patents on the
22nd November 1882.
CHARLES PILKINGTON of Haydock in the County of Lancaster, Engineer, and
"IMPROVED VALVES FOR AIR
JAMES FORREST of the same place, Engineer,
COMPRESSORS
"
The invention relates to the construction of the admission and emission valves of
apparatus in which air or aeriform fluids such as gases are compressed by means of
a pump or like appliance.
The object is to so construct such valves that they shall open and close freely
and smoothly without shock or vibration (when the engine is running at a high
speed) and give a large area for the passage of the aeriform fluid without undue
pressure on the valves either in opening or closing.
The invention consists essentially in constructing the said valves with inner and
outer faces which seat on two seats. The valves are of annular form or hinged of
the flap kind. They are held in position by a spring or springs and when open
(either for the entry into or egress from the cylinder) they allow the aeriform fluid
to flow past the faces in opposite directions that is to say, from a smaller periphery
to a larger in passing one face, and from a larger to a smaller in passing the other
face. We thus avoid the clatter usually made when air or aeriform fluid passes in
one direction only.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Pilkington and James Forrest in the Great Seal Patent Office
on the 21st May 1883.
CHARLES PILKINGTON of Haydock in the County of Lancaster, Engineer, and
JAMES FORREST of the same place, Engineer, "IMPROVED VALVES FOR AIR
COMPRESSORS
"
The invention relates to the construction of the admission and emission valves
of apparatus in which air or aeriform fluids such as gases are compressed by means
of a pump or like appliance.
The object is to so construct such valves that they shall open and close freely
and smoothly without shock or vibration when the engine is running at a high
'speed, and give a large area for the passage of the aeriform fluid without undue
pressure on the valves either in opening or closing.
The invention consists essentially in constructing the said valves with inner and
outer faces which seat on two seats. The valves are of annular form or are hinged
or of the flap kind. They are held in position by a spring or springs and when
open either for entry into or egress from the cylinder they allow the aeriforin fluid
to flow past the faces in opposite directions, that is to say from a smaller periphery
to a larger in passing one face and from a larger to a smaller in passing the other
face.
DESCRIPTION OF THE DRAWINGS
By constructing our said valves as herein before outlined each with two faces and
by adjusting the widths and areas of the said faces so that the vacuum formed by
the passage of aeriform fluid on the outer edge of the outer face is counteracted by
the increase of pressure on the inner, edge of the inner face we avoid the tendency
to clatter and dance so common in air compression valves especially in the inlet
valves when the neriform fluid flows in one direction only; obtain a large area for
the admission and emission of aeriform fluid so reducing the height of the lift
required; and avoid the heavy pressure on the back of the valve which causes
violent striking of the valves against their seats and consequent heavy wear and
tear, yet have sufficient pressure to close the valves quickly.
Fig 1 is a longitudinal vertical section of the end of a cylinder a with inlet
valve bannular shape connected by ribs c and boss d to a spindle e. ff valve
seatings connected by webs g. the centre seating f'being cast so as to form a guide
or bearing for the spindle e and carry a stuffing box h to prevent leakage of
aeriform fluid past the spindle e. The spring i rests on the top of the stuffing box
gland and reacts on the adjusting nut ; screwed on the spindle e A cylinder
•cover.
The valves and seatings are preferably of brass or gun metal and the tension of
the spring is such as to cause the valve after being opened to return lightly to its
seat. The arrows show the direction taken by the aeriform fluid which passes the
narrow face f of the seating from an inner to an outer periphery and the wider
face of the seating from an outer to an inner periphery. The only part of the
valve acted on by the pressure of the air is the space between the outer edge of
the outer face f¹ and the inner edge of the inner face f the ribs c and boss d.
The valve seating f¹ is bolted or secured to the cylinder cover k and the
valve and seating may be removed and examined without breaking the cylinder
cover joint.
1

page_text: Fig 2 is a longitudinal vertical section of the end of a cylinder showing an outlet
valve under our invention for aeriforin fluid, a cylinder, annular valve, c con-
necting ribs, d boss. e spindle. ff1 seatings. g connecting webs, delivery
box cast with or secured to the cylinder cover. m delivery box cover provided
with a guide bearing for the spindle e and with a stuffing box h spring sur-
rounding the spindle e and resting on the nut j screwed on the said spindle. The
spring i reacts against the cross head n held in position by the standards o secured
to the cover m of the delivery box. The air passes the faces ff' as shown by the
arrows in manner similar to that above described.
Fig 3 is a section of the end of a cylinder showing a hinged or flap inlet valve
under our invention. The valve b works on a pin p. ff¹ are the inner and outer
Beatings formed on the cylinder cover k. q links connecting the valve b to the
spindle e cg connecting ribs or webs; h stuffing box. i spring. j adjusting nuts.
The arrows show the direction of motion of aeriform fluid which is substantially
the same as shown in fig 1.
Fig 4 is a section of the end of a cylinder showing a hinged or flap outlet valve
constructed and acting in accordance with our invention. The valve 6 works on a
pin p and is connected to the spindle e by links q. ff' seatings formed on the
cylinder cover the other parts are substantially the same as those described under
fig 2 and like letters denote the same parts. The arrows show the direction of
motion of aeriform fluid. It will be observed that by taking off the cover m the
valve may be removed for examination.
Fig 5 is a view in section of a modification of annular inlet valve under our
invention. The same letters are marked on equivalent parts as in fig 1. In this
modification the bearing faces of the valve and seatings are beveled and a supple-
mentary bearing k to prevent leakage is provided.
It will be evident that modifications of various parts may be made without
departing from our invention for instance more than one spring or springs of
different forms or constructions may be used. The forms of the thrust for the spring
or springs and the shapes of the valves may be varied and the proportions and
areas of the seatings may differ.
Having now described and illustrated the said invention in such manner that
others will be enabled to carry our said improvements into effect We claim:-
Valves for air compressors with, inner and outer faces seating on two seats, a short
lift and large areas for passage of aeriform fluid past the faces in opposite directions
the whole constructed and the parts combined substantially as and for the purposes
setforth.
In Witness Whereof I the said James Forrest have hereunto set my hand
and seal this seventeenth day of May in the year of Our Lord, one thousand
JAMES JOHNSON
Patent Office
4 Clayton Sq*.
Liverpool
Witness
JAMES FORREST (L.S.)