IMPROVEMENTS IN APPARATUS FOR CON- TROLLING THE ADMISSION OF STEAM TO PRIME MOVERS
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Charles Grantley Beechey at the Office
of the Commissioners of Patents on the 27th November 1877.
CHARLES GRANTLEY BEECHEY, of Newton Heath, near the City of Manchester,
in the County of Lancaster, Engineer. "IMPROVEMENTS IN APPARATUS FOR CON-
TROLLING THE ADMISSION OF STEAM TO PRIME MOVERS."
My Invention relates to the apparatus employed to cut off the steam before the
termination of the strokes of the pistons of steam-engines, and to apparatus for
varying and controlling the points of cutting off, as may be required by the varying
loads upon such engines.
When carrying my said Invention into effect I employ a sliding cut-off valve or
sliding cut-off valves, and I control the movements of such valve or valves by
means of a sliding cam plate, and I actuate the said cam plate and the main slide
valve by means of a crank or of cranks acting upon cross heads or parts which are
formed with slots inclined in opposite directions.
In the form of valve which I prefer to employ, the cut-off valve slides within
the main slide valve casting or between the main valve and a covering plate, which
is or are formed with recesses corresponding to the steam inlet ports of the main
valve. The said cut-off valve is formed with through ports, or is formed in two
parts, each of which has a through port.
When a port of the cut-off valve is opening or closing it admits or cuts off the
steam at four points.
This construction of valve may be employed without being necessarily combined
with the remainder of my Invention.
I prefer to arrange the spindle of the cut-off valves to slide within a hollow
spindle which slides with the main valve.
The cut-off valve spindle is connected with a bell-crank lever which is mounted
on a slide or part which is connected with the main valve spindle. One end of the
said lever is connected with the cut-off valve spindle, the other end of the said lever
being provided with a bowl or roller which works in a slot in the aforesaid cam
ID 271

page_text: .
plate. The said cam plate is connected with the sliding block of a slotted curved
lever which is connected with the sliding spindle of one of the aforesaid slotted
cross heads.
The said sliding block is or may be connected with a suitable governor which
moves the said block in the slot, and thereby controls the cut-off. Each of the said
cross heads is formed with a slot in which a block which is mounted on the driving
crank pin is fitted to slide, or the said slot may be formed by two cheeks or parts
connected together, or the said block may be arranged to slide upon a bar or part
so long as the intended result is obtained. The said slot is inclined from a line
which would be at right angles to the line of notion of the cross head. The angles
of inclination of the two cross heads being reversed.
The effect of this arrangement is, that, although both cross heads may be actuated
by one crank, the two cross heads move in opposite directions at some parts of the
stroke, and also that the movements of the main valve and the said cam plate are
accelerated and retarded at certain parts of the stroke compared with the action of
the ordinary excentric.
When in action the said cam plate is caused to act upon the aforesaid bell-crank
lever at the times when the steam is to be cut off, the times of cutting-off being
controlled by the positions of the sliding block in the aforesaid slotted lever.
Ordinary eccentrics may be employed in lieu of the said slotted cross heads or
equivalent appliances, if preferred, and also the said slotted cross heads or appliances
provided with blocks or carriages sliding in directions inclined in the manner
indicated may be employed in lieu of the ordinary excentrics for actuating slide or
cut-off valves.