IMPROVEMENTS IN MACHINERY OR APPARATUS FOR COMPRESSING OR FORCING AIR
Year: 1877

page_text: LETTERS PATENT to John Shaw, of Ovenden, near Halifax, in the County of
York, Contractor's Agent, and William Timbrell Clarke, of Queensbury, near
Halifax, aforesaid, Mechanical Engineer, for the Invention of "IMPROVEMENTS
IN MACHINERY OR APPARATUS FOR COMPRESSING OR FORCING AIR."
Sealed the 13th April 1877, and dated the 3rd January 1877.
PROVISIONAL SPECIFICATION left by the said John Shaw and Williamı
Timbrell Clarke at the Office of the Commissioners of Patents on the 3rd
January 1877.
JOHN SHAW, of Ovenden, near Halifax, in the County of York, Contractor's
Agent, and WILLIAM TIMBRELL CLARKE, of Queensbury, near Halifax aforesaid,
Mechanical Engineer. "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR COM-
PRESSING OR FORCING AIR."
This Invention relates to apparatus to be used for opening and closing the valves
of air compressors, blast engines, and other similar apparatus, and consists,-
Firstly. In operating the inlet valves by means of a hydraulic apparatus com-
prising an ordinary cylinder and piston, the cylinder being attached to the piston
rod or other moving part of the compressor, and the hydraulic piston rod being
connected to a cross head, to which the said valve spindle of the compressor are
attached.
Secondly. We may also work the inlet valves by a piston and cylinder fixed as
above described, but without oil or water, the movement necessary for working the
valves being produced by the formation of a vacuum at the end of each stroke.
Thirdly. Instead of the appliances above described we may use a steam cylinder
and piston arranged so as to act either in conjunction with or independantly of the
moving parts of the compressor.
Fourthly. We may operate such valves by means of one or more eccentrics suitably
arranged and worked from any convenient source.
Fifthly. By using a small cylinder and piston to each inlet valve we may operate
the same by compressed air introduced into the small cylinders from the cylinder of
the compressor.
Sixthly. The valves may be worked by tappits or projections on the piston rod,
which strike the valve spindles or levers or rods connected therewith at each recip-
rocatory motion of the piston.

page_text: Seventhly. We may attach a rack to the piston rod gearing with a pinion suitably
fixed, which is caused to revolve with the motion of the rack. A stud or pin in the
said pinion at each revolution thereof actuates the valve either directly or through
the intervention of suitably arranged levers or rods.
Eightbly. We propose to close the exhaust or outlet valves by means of pins and
levers in connection therewith, which are actuated at each stroke of the cross head
of the inlet valves, or by friction in a similar manner to that in which inlet valves
are now operated.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Shaw and William Timbrell Clarke in the Great Seal Patent
Office on the 3rd July 1877.
JOHN SHAW, of Ovenden, near Halifax, in the County of York, Contractor's
Agent, and WILLIAM TIMBRELL CLARK, of Queensbury, near Halifax, aforesaid,
Mechanical Engineer. "NEW OR IMPROVED METHODS OF AND APPARATUS FOR
OPERATING THE VALVES OF AIR COMPRESSORS."
This Invention relates to apparatus to be used for opening and closing the valves
of air compressors, and consists,-
Firstly. In operating such valves by means of a hydraulic apparatus comprising
one or more ordinary cylinders and pistons which are attached to the piston rod or
other moving part of the compressor, and the hydraulic piston rod or rods being
connected to a cross head, to which the valve spindles of the compressor are
attached.
In order that our Invention may be more fully understood we have hereto
annexed two Sheets of Drawings marked with figures and letters of reference.
Figs. 1, 2, and 3 represent plan, sectional elevation, and end view of an ordinary
air compressor, with one form of the first part of our Invention applied thereto.
This air compressor is fixed upon the same bed as and actuated by an ordinary
horizontal steam engine, but can of course be placed on a separate bed and worked
by a belt or any other arrangement.
A is the air cylinder, B being the inlet valves, which are operated simultaneously
by the cross head C, to which they are connected; D is the piston rod of the air
compressor, receiving its motion from the crank of the steam engine, and attached
to this rod are hydraulic cylinders E (see detail, Fig. 4); F are the piston rods,
which pass through the hydraulic cylinders, and are connected to the cross head C.
Each cylinder has two ports or openings a, b, which communicate through the
passage c. It will be seen that if the cylinder is filled with fluid, and the piston
moved from end to end, the fluid will be displaced from the cylinder, and forced
through the port in front of the piston, but will enter through the one behind it,
according to the direction in which the movement is effected. According to our
Invention the cylinder is moved and the piston is stationary, except at the com-
mencement of the stroke in each direction, when the resistance offered by the fluid
causes the piston to move sufficiently to open or close the valves. This operation
may be reversed, the piston being made to move, and the cylinder made stationary,
and connected to the valves.
Secondly. In working such valves by a piston and cylinder fixed as above
described, but without oil or water, the movement necessary for working the valves
being produced by the formation of a vacuum at the end of each stroke. It will be
observed that the two pistons or collars m, n, are perforated, the perforations being
covered by the two loose collars o, p, which are pressed against the pistons by the
spring 8. When the cylinder or piston has reached the end of its stroke the air or
fluid between the cover and the port passes through the orifices in the piston, the
loose collar and spring acting as a valve. On the return stroke there will be &
yacuum formed until the piston has passed the port, and the air in the cylinder will

page_text: be compressed, the resistance offered to the formation of the said vacuum being
sufficient to effect the movement of the valves.
Thirdly. Such valves may be worked by one or more steam cylinders and pistons
arranged so as to act either in conjunction with or independently of the moving
parts of the compressor.
In Fig. 5 G is a steam cylinder, the piston H of which is connected to the cross
head C. The valve of the steam cylinder is operated at the end of each stroke of
the air compressor piston D by means of the slide rest d, which at each movement
of the said piston D strikes projection e on the rod f, which is connected to the valve
spindle by levers g.
Fourthly. We may operate such valves by means of one or more cams, tappets, or
eccentrics suitably arranged and worked from any convenient source.
In Fig. 6 is shewn a tappet J on the fly wheel or crank shaft of the steam engine,
this tappet working in a yoke or strap of which two sides are flattened, so that in
revolving the tappet will push the said yoke in opposite directions alternately, and
so operate the cross head C, and consequently the valves of the air compressor
cylinder.
Fifthly. The valves may be worked by tappets or projections on the piston rod,
which strike the valve spindles or levers or rods connected therewith at each recip-
rocatory motion of the piston.
In Fig. 7 the tappet or projection K on the piston rod works in the slotted rod L,
causing it to move slightly lengthwise at the end of cach stroke, and through the
medium of the levers h operate the cross head C.
Sixthly. We may attach a rack to the piston rod gearing with a pinion suitably
fixed, which is caused to revolve with the motion of the rack. A stud or pin in the
said pinion at each revolution thereof actuates the valves either directly or through
the intervention of suitably arranged levers or rods.
In Fig. 8 it will be seen that as the slide rest M reciprocates, the rack thereon
will impart an oscillatory motion to the toothed wheel N, so that the pin j in the
rim thereof will actuate the levers O and cross head C.
Seventhly. We propose to close the exhaust or outlet valves by means of pins
and levers in connection therewith, which are actuated at each stroke of the cross
head of the inlet valves.
In witness whereof, I, the said John Shaw, on behalf of myself and the
said William Timbrell Clark, have hereunto set my hand and seal, this
Twenty-fifth day of June, in the year of our Lord One thousand eight
hundred and seventy-seven.
JOHN SHAW. (L.S.)