Cut Off or Expansion Valve
Year: 1885

page_text: Cut Off or Expansion Valve.
ROLAND BENTLEY of 2 Carlisle Street, Dresden, in the County of Stafford
Mechanical Engineer and THOMAS FORD of 41 Anchor Terrace Longton in the
County of Stafford Mechanical Engineer, do hereby declare the nature of our
invention for AN EQUILIBRIUM SLIDE VALVE FOR STEAM ENGINES WITH VARIABLE
CUT OFF OR EXPANSION VALVE, to be as follows:-
:-
This invention consists of an equilibrium hollow cylindrical slide valve, worked
by an eccentric from the main shaft as in the ordinary way, with cylindrical valve
enclosed therein, and worked by the governors or otherwise, and intended to act as
a variable cut off or expansion valve. The main valve is fitted in the cylindrical
valve chest, the passages of which are placed in a diagonal or oblique form the
object of which, is to quicken the variation of the expansion valve, but the
inventors claim the right of using either the diagonal or parallel passages, as
the main valve may be used either with or without the variable expansion valve.
The variable expansion valve being fitted inside the main valve travels with the
same, and regulates the steam to engine by a rotary motion given by the governors,
to which provision is attached for adjustment at will, or, by any other application
or arrangement we may think fit to adopt to work the expansion valve."
J
I

page_text: .
An Equilibrium Slide Valve for Steam Engines with Variable
Cut Off or Expansion Valve.
ROLAND BENTLEY of 2 Carlisle Street Dresden in the County of Stafford
Mechanical Engineer, and THOMAS FORD of 41 Anchor Terrace Longton in the
County of Stafford Mechanical Engineer do hereby declare the nature of our
invention for AN EQUILIBRIUM SLIDE VALVE FOR STEAM ENGINES WITH VARIABLE
CUT OFF OR EXPANSION VALVE to be as follows and in. what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention consists of an equilibrium hollow cylindrical slide valve worked
by an excentric from the main shaft as in the ordinary way with cylindrical valve
enclosed therein and worked by the governors or otherwise and intended to act as
a variable cut off or expansion valve. The main valve is fitted in the cylindrical
valve chest the passages of which are placed in a diagonal or oblique form, the
object of which is to quicken the variation of the expansive valve, but the
inventors claim the right of using either the diagonal or parallel passages as
the main valve may be used either with or without the variable expansion valve
The variable expansion valve being fitted inside the main valve travels with the
same and regulates the steam to engine by a rotary motion given by the governors
to which provision is attached for adjustment at will or by any other application
or arrangement we may think fit to adopt to work the expansion valve.
And in order that our invention may be clearly understood we will proceed to
describe the same with reference to the drawings annexed.
Figure 1 shews a section of cylinder and valve chest and main and cut off valves
through line C. D. (Figure 4) The steam enters the valve chest I by branch E
(Figure 2) thence into the cylindrical cut off valve B (Figure 1) after passing
through cut off valve B the steam enters the cylindrical main valve A thence into
the ports J & K into cylinder, and exhausting by port L in valve to port M in
cylinder as in the ordinary way.
The valve chest I is truly bored out to receive the main valve A. which is made
a perfect sliding fit, the cylindrical main valve A (Figure 1) has a to and fro
sliding motion imparted to it by spindle C which is connected to rod worked by an
excentric on the main shaft.
The cylindrical cut off valve B (Figure 1) is properly turned to fit in main
valve A (Figure 1) which receives its sliding motion in a similar manner to the
main valve A. from a second excentric on the main shaft the rod of which is
coupled to the spindle F.
The spindle F of cut off valve B has a feather key sunk in at N and secured to
valve B by 2 collars and set screws or taper pins. The arm X (Figure 1) is cast on
the valve chest cover on which provision is left for receiving brass bush Y through
which the spindle F travels to and fro: at this end of spindle F there are two
feather keys which pass through two seats in bush Y: the lever H being secured
to bush Y when lifted by the governor to which it is attached, gives the rotary

page_text: motion to cut off valve B to which it gives the necessary lap over the oblique ports
simultaneously with the sliding motion given to the same by the excentric on the
main shaft.
.
Figure 2 shews a section of the cylindrical valve chest through line R. S.
(Figure 4) and shews the oblique ports or passages O. P (Figure 2) which extend
nearly half way round the cylindrical valve chest.
The valve chest I (Figure 2) is truly bored between T & U on the top and V & W
on the bottom and vice versa on the other side of the valve chest: the rest portion
of the valve chest I being cored out to a wider diameter to allow the steam to get
at the back of the valve, so as to counterbalance the steam in front of it, and thus
render the main valve an equilibrium or truly balanced one.
Figure 3 on the annexed drawing shews the cut off valve B: it will be seen that
the back and front of the valve being of the same area, and the steam being
admitted inside the valve, makes the valve also an equilibrium one. This valve
being of an oblique form the rotary motion given to it by the governors increases
the lap of the valve, thereby giving it the variable cut off: when the governor balls
are down, the valve B cuts off steam at three quarters stroke: and when extended
at full cuts off at one quarter stroke, the rotary motion thus varying the cut off
from one quarter to three quarter stroke.
Having now particularly described and ascertained the nature of our said
invention we now proceed to our claim.
First. The improved method of imparting steam to the cylinder through our
equilibrium cylindrical slide valve A (Figure 1) and general arrangement and
construction of valve chest I (Figure 1) and for the proper working of the same, all
being arranged to act substantially in the manner and for the purpose hereinbefore
fully described and represented in the Drawings hereto annexed.
Second. We claim the improved method of cutting off steam by our equilibrium
cylindrical cut off or expansion valve B (Figure 1) and the general arrangement of
its simultaneous rotary and sliding motions substantially as described and shewn in
the drawings annexed.
.
Third. We claim this method of balancing or making perfect equilibrium both
main and cut off valves substantially as described and shewn in the drawings
annexed.
Lastly. We claim the improved general arrangement and combination of main
and cut off valves and gear, for working and regulating steam engines substantially
in the manner hereinbefore described and represented in the drawings annexed.
ROLAND BENTLEY,
THOMAS FORD,
Patentees.