IMPROVEMENTS IN OR RELATING TO THE VALVES AND THE CYLINDERS OF AIR-COMPRESSING ENGINES, A PART OF WHICH IS ALSO APPLI- CABLE TO OTHER ENGINES OR PUMPS
Year: 1877

page_text: LETTERS PATENT to John Scarisbrick Walker and Thomas Ascroft Walker,
both of Wigan, in the County of Lancaster, Mechanical Engineers, for the
Invention of IMPROVEMENTS IN OR RELATING TO THE VALVES AND THE
CYLINDERS OF AIR-COMPRESSING ENGINES, A PART OF WHICH IS ALSO APPLI-
CABLE TO OTHER ENGINES OR PUMPS."
Sealed the 21st May 1878, and dated the 28th November 1877.
PROVISIONAL SPECIFICATION left by the said John Scarisbrick Walker
and Thomas Ascroft Walker at the Office of the Cominissioners of Patents on
the 28th November 1877.
JOHN SCARISBRICK WALKER and THOMAS ASCROFT WALKER, both of Wigan, in
the County of Lancaster, Mechanical Engineers. "IMPROVEMENTS IN OR RELATING
TO THE VALVES AND THE CYLINDERS OF AIR-COMPRESSING ENGINES, A PART OF
WHICH IS ALSO APPLICABLE TO OTHER ENGINES OR PUMPS."
33
First. We prevent the inlet valves opening, except when there is a partial vacuum
behind them, and then by a gentle well-regulated friction and steadying prevent
their "dancing or flapping." The mode of doing this which we prefer is as
follows: We construct a flap valve of metal opening inward in the cylinder cover,
and hinged to a rod passing through the cover from edge to edge of the saine,
chainfered off at the ends to suit the contour of the cylinder cover. At the back of
this valve, on the cylinder cover, we cast a small cylinder, called the resistance
cylinder, with a removeable perforated cover. This small cylinder is bored out, and
a piston, called the resistance piston, is fitted therein; the rod of this piston is
hinged to both the piston and to the valve in the main cylinder cover. Near the
valve and in the resistance cylinder is a solid abutment, and between that abutment
and the piston we place a (preferably volute) spring or springs in compression, called
the resistance spring, abutting against the abutment on the one side and the piston
on the other.
The resistance spring keeps the valve closed, except when a partial vacuum is
formed behind it.

page_text: The resistance piston can be made broad and fitted with rings, but we prefer to
have a loose half bush or a long curved plate fitting into a longitudinal recess in the
resistance cylinder or in resistance cylinder and piston. On the back of this is
preferably a projection against which a spring, called the friction spring, re-acts,
except in compression, by a regulating screw or its mechanical equivalent.
By regulating the screw the pressure of the spring and plate or bush against the
resistance piston can be regulated to a nicety at all times.
The resistance spring is so constructed that it can only give way a certain distance,
so as to prevent the valve ever going too far in; we also put an abutinent on the
valve which supplements and completes this stoppage at the right point.
To the resistance piston we sometimes attach a long bolt jutting outwards in the
centre line of the resistance cylinder, and place a spring round it abutting against
a plate and nut on the bolt and against the resistance cylinder. This spring can
supplement or supersede the before-mentioned resistance spring. The bolt is turned
to a smaller diameter at the end, and slides in a suitable guide attached to the
resistance cylinder; this guide is usually a cross head in two pieces, bolted together
and supported by two long bolts or screwed pedestals projecting from the resistance
cylinder.
The friction spring and its accompanyments or any mechanical equivalent that
will regulate the friction in the guide can be fitted to the guide instead of to the
resistance cylinder.
We place a grating behind the valves to prevent it or any part of it entering the
main cylinder in case of bad working.
Second. In the ports of blowing cylinders and air pumps a great waste occurs
through air collecting in them, and re-expanding at each stroke; we therefore
construct our outlet valves with their surfaces when closed forming an actual part
of the cylindrical contour of the inside of the cylinder. To effect this we place the
valve seating embedded in the port, and so construct our valves with a contour of
the same curve of the cylinder that they shall exactly fill the cylinder void, leaving
no place for accumulation of air except the ordinary clearances at each end of
the cylinder, which we reduce to the lowest possible amount. This arrangement is
applicable to other engines and pumps, as well as to blowing engines.
Third. In single-cylinder air-compression engines used intermittently the pistons
are very apt to stop at the end of the stroke, in which case it is very difficult to start
them afresh; now, we avoid this by placing a cock, called the escape-cock, in each
cylinder cover of the air cylinder, and also bring a pipe with a stop-cock from the
compressed air chamber to each end of the cylinder.
When the engine stops, by opening the escape-cock at one end, admitting com-
pressed air to the other end, we start the engine and bring the piston to any desirable
part of the stroke. All the cocks being now closed, it remains in this position till
the engine requires starting in due course.

page_text: IL
Seal Patent Office on the 28th May 1878.
JOHN SCARISBRICK WALKER and THOMAS ASCROFT WALKER, both of Wigan, in
the County of Lancaster, Mechanical Engineers. "IMPROVEMENTS IN OR RELATING
TO THE VALVES AND THE CYLINDERS OF AIR-COMPRESSING ENGINES, A PART OF
WHICH IS ALSO APPLICABLE TO OTHER ENGINES OR PUMPS."
In the working of valves for compressing or exhausting air and other gaseous
fluids, it is found that the valves are apt to dance or flap while the air is passing
through the same, so preventing them working safely at any but a low velocity.
The first part of our Invention is designed to prevent this dancing, no matter
what velocity the engine is going at, by a gentle adjustable amount of friction and
steadying. The mode of doing this which we prefer is as follows:-It is shewn in
the Drawings, on Sheet 1, in which,-
Fig. 1 is a plan of apparatus.
Fig. 2 a section through r, y.
Fig. 3, section through spring and elevation of top bearing.
Fig. 4 is a section of valve and link, transverse to Figure 1.
Fig. 5, elevation of valve and part of cylinder cover.
We construct a flap valve A of metal opening inward in the cylinder cover B,
and hinged on a rod D passing through a cover B from edge to edge of the same,
chamfered off at the ends to suit the contour of the cylinder cover. At the back of
this valve, on the cylinder cover B, we cast a sinall cylinder E with a removable cover F.
This small cylinder is bored out, and a piston G is fitted therein. The rod or link C
of this piston is hinged to both the piston and the valve A. Near the valve and in
the cylinder E is a solid abutment H, and between that abutment and the piston
we usually place a (preferably volute) spring or springs I in compression, abutting
against the abutment on one side and the piston on the other.
The piston G is made broad and fitted with rings.
To the piston G we attach a long bolt J jutting outwards in the centre line of the
cylinder E, and place a spring K round it, abutting against a plate L and nut M on
the bolt and against the cylinder E. The spring K is employed, first, to assist in
balancing the friction at P. and G; and second, to moderate the violence of the sudden
opening of the valve and assist in returning it to its face. The bolt is turned to a
smaller diameter at the end, and slides in a suitable guide N attached to the
cylinder E. This guide N is usually a cross head in two pieces, bolted together
and supported by two long bolts or screwed pedestals O projecting from the
cylinder E.
In order to give a regulated friction and prevent the too free action of the valve,
we place against the loose and adjustable cap P of the guide N a spring or cylinder
of rubber Q, which can he compressed to any required extent by washer and screw R.
Instead however of this arrangement we sometimes put the friction on piston G;
this is shewn in detail on Sheet 2, Fig. 6. P¹ is a loose half bush or strip working
against piston G; it can, if desirable, be recessed into it by cutting a longitudinal
recess or slot in the surface of the cylinder E or cylinder E and piston G. On the
back of this half bush or strip is a boss T fitting into a cylinder S branching from
the side of cylinder E, and in this cylinder S is a spring Q' with a washer and
bolt R' above in nut, for exactly regulating the friction of the strip P¹ on the
piston G..
The object of making the tension of springs K and Q and Q₁ adjustable froin the
outside is to adjust them while the engine is working, it being found impracticable
to adjust then properly except by actual trial after the engine has started, the
friction at P or P₁ and compression of springs requisite varying with the velocity of
the engine, and other variable circumstances.
The apparatus is equally applicable to other forms of valves than that shown.

page_text: We sometimes place a grating behind the valve to prevent it or any part of it
entering the main cylinder in case of fracture.
Second. In the ports of blowing cylinders and air pumps a great waste occurs
through air collecting in them and re-expanding at each stroke; we therefore some-
times construct our outlet valves with their surfaces when closed formning an actual
part of the cylindrical contour of the inside of the cylinder. This is shown in Fig. 8,
Sheet 2; in these A¹ is the valve, having wings A₁ to guide it; B₁ is the cylinder;
U, seating for valve; F¹, L, cups to contain spring K₁; M', nut; V, screw to give
requisite amount of compression. Valves formed in this way exactly fill the cylinder
void, leaving no place for accumulation of air except the ordinary clearances at each
end of the cylinder, which we reduce to the lowest possible amount. This arrange-
ment is applicable to other engines and pumps, as well as to blowing engines, but
more especially in those cases where gaseous fluids are actuated upon.
Third. In single-cylinder air-compression engines used intermittently the pistons
are very apt to stop at the end of the stroke, in which case it is very difficult to start
then afresh; now, we avoid this by placing a cock, called the escape-cock, in each
cylinder cover of the air cylinder, and also bring a. pipe with a stop-cock from the
compressed air chamber to each end of the cylinder.
When the engine is about to stop, by opening the escape-cock at one end, admit-
ting compressed air to the other end, we place the engine and bring the piston to
any desirable part of the stroke. All the cocks being now closed, it remains in this
position till the engine requires starting in due course.
Having now described our Invention and the best modes known to us of carrying
it into effect, we wish it to be understood that what we believe to be new and
desire to protect under the herein-before in part recited Letters Patent is, -
1st. The mode described of preventing the violent action of valves very liable to
dance or knock, such as the inlet valves of air-compressing engines, by a combi-
nation of adjustable friction and spring resistance.
2nd. The arrangement of this adjustable friction and spring resistance in such
manner that they can be adjusted while the engine is working.
3rd. The apparatus for preventing violent action in valves of air-compressing
engines, substantially as described.
4th. The manufacture of exit valves of air-compressing and other cylinders, with
their faces following approximately or exactly the contour of the cylinder.
5th. The exit valve apparatus, substantially as described and shewn in Fig. 6.
6th. The mode of and also the apparatus for starting single-cylinder air compres-
sion engines, substantially as described in part three of this Specification.
In witness whereof, I, the said John Scarisbrick Walker, for and on behalf
of myself and the said Thomas Ascroft Walker, have hereunto set my
hand and seal, this Twenty-fourth day of May, in the year of our Lord
One thousand eight hundred and seventy-eight.
JOHN SCARISBRICK WALKER. (L.S.)
Witness,
W. P. THOMPSON,
British & International Patent Agent,
6, Lord Street,
Liverpool.