Improved Slide Valve Arrangement for Steam Engine Cylinders.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improved Slide Valve Arrangement for Steam Engine Cylinders.
I, ALFRED JOHN BALKWILL, of 6, Calder Vale Road, Wakefield, in the County
of York, Works Manager, do hereby declare the nature of this invention to be
as follows:-
The object of my invention is an improved slide valve arrangement for steam
engine cylinders whereby with special ports and valve, part of the steam after
completing its work at one side of the piston traverses the valve to give out work
on the opposite side of the piston the remainder of the steam being exhausted.
For the purpose of my invention, in addition to the usual steam entry and
exhaust ports in the valve face of the cylinder, I provide another or brauch port
in the valve face, but leading out from one of the ordinary ports, this double
port having only one port in the cylinder.
The slide is formed with an external chamber or port outside its ordinary
exhaust port for communication with the additional or auxiliary port and the
ordinary port on the opposite side for the passage of part of the steam from one
side of the piston to the other, or to one side of another piston in another
cylinder.
The working of my improved slide valve arrangement is as follows:-The
steam pushes the piston down and at stroke, the slide valve shuts the steam off.
Then it expands slightly. Just before the piston gets at the bottom end, steam
passes round through the top side through the external port of the slide valve to
The bottom side of the piston and pushes the piston upwards. At a certain point,
the steam is shut off but at the very instant it is shut off, the remainder is
exhausted to the atmosphere to the central port. On the return stroke, the
whole of the steam which had previously passed through the top to the bottom
is exhausted.
When the steam at the top side of the piston is exhausted there is only a
slight exhaust, but on the down stroke there is a full exhaust, the steam there-
fore carries out the conditions of working perfectly.
Although steam goes in at the top side, it is nearly all exhausted from the
bottom side. Thus for a single acting pump, this steam instead of exhausting
from the bottom side to the atmosphere by passing it over to the top side of the
piston of another pump, which would make it a double pump, would fulfill the
same conditions as in the first cylinder, so that it practically would have four
grades of expansion, two in one cylinder and two in the other. This latter
arrangement will reduce the consumption of steam again considerably from the
test I have made with one cylinder only on a single ram pump.
Dated this 18th day of February 1899
R. CORE GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said Alfred John Balkwill.

page_text: Improved Slide Valve Arrangement for Steam Engine Cylinders.
I, ALFRED JOHN BALKWILL, of 6, Calder Vale Road, Wakefield, in the County
of York, Works Manager, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
The object of my invention is an improved slide valve arrangement for steam
engine cylinders whereby with special ports and valve, part of the steam after
completing its work at one side of the piston traverses the valve to give out work
on the opposite side of the piston the remainder of the steam being exhausted.
For the purpose of my invention in addition to the usual steam entry and
exhaust ports in the valve face of the cylinder, I provide another or branch port
in the valve face but leading out from one of the ordinary ports this double
port having only one port in the cylinder.
The slide is formed with an external chamber or port outside its ordinary
exhaust port for communication with the additional or auxiliary port and the
ordinary port on the opposite side for the passage of part of the steam from one
side of the piston to the other, or to one side of another piston in another
cylinder.
The working of my improved slide valve arrangement is as follows:-The
steam pushes the piston down and at 4 stroke the slide valve shuts the steam off.
Then it expands slightly. Just before the piston gets at the bottom end, steam
passes round through the top side through the external port of the slide valve to
the bottom side of the piston and pushes the piston upwards. At a certain point
the steam is shut off but at the very instant it is shut off the remainder is
exhausted to the atmosphere to the central port. On the return stroke, the
whole of the steam which had previously passed through the top to the bottom
is exhausted.
When the steam at the top side of the piston is exhausted there is only a
slight exhaust but on the down stroke there is a full exhaust, the steam there-
fore carries out the conditions of working perfectly.
Although steam goes in at the top side, it is nearly all exhausted from the
bottom side. Thus for a single acting pump this steam instead of exhausting
from the bottom side to the atmosphere by passing it over the top side of the
piston of another pump, which would make it a double pump, would fulfil the
same conditions as in the first cylinder so that it practically would have four
grades of expansion, two in one cylinder and two in the other.
This latter arrangement will reduce the consumption of steam again consider-
ably from the test I have made with one cylinder only on a single ram pump.
My invention will be clearly understood from the accompanying drawings in
which each figure represents in section an engine cylinder, slide valve, and
valve casing.
Figure 1 shows the slide valve in position with the inlet port slightly open for
admittance of live steam to the top part of cylinder for commencement of pistons
stroke, the exhaust port being open to bottom of piston.
Figure 2, shows the slide valve moved for a full admission of live steam to the
top of piston, the piston at this time having reached about one third of its stroke.
Figure 3, shows the valve moved over to shut off the steam inlet, the exhaust
being open from opposite end of cylinder.
Figure 4 shows the piston at the end of its stroke and the ports and supple-
mentary passage in the valve open for the transfer of the used steam to the

page_text: opposite end of cylinder for re-use against the piston for the return stroke
expansively.
Figure 5 shows the position the valve and piston occupy when the steam trans-
ference passage is cut off and the exhaust open to top part of the cylinder.
A, cylinder, B, piston C 1) cylinder ports. E ordinary exhaust. I slide valve.
G slide valve casing. H additional through port in slide valve F. I branch
K valve rod.
port from port D of cylinder A for partial exhaust. piston rod.
L steam supply pipe. M usual exhaust passage in slide valve F.
The action is as follows presuming the piston B is at the top of its stroke as
indicated at Figure 1.
Steam 'enters valve casing G by the pipe L and passes through the port C for
exerting its power against the piston B until the valve F cuts off in the usual
manner and the piston B travels to about that portion of its stroke as indicated
in Figure 3, the steam contained within the cylinder expanding and operating
on the piston to complete the stroke. As the piston is just arriving at the end
of its stroke the slide valve is moved as at Figure 4 for the greater portion of
the used steam to return by the port C into and through the supplementary or
additional port I of the valve F and these through the port D
the back of the piston B for use expansively against the back
of the piston B for the return stroke and as soon as the piston arrives at a
certain portion of its return stroke (about as at Figure 5) the valve F closes the
ports HC and cuts off further transference of steam from one side of the
piston to the other, at the same time the port M is open to port C and the con-
tinued expansion of the steam on the underside of the piston causes the steam
remaining on the top part of the piston to be exhausted.
to
On the next motion of the slide valve F as at Figure 1 the supplementary or
additional port H is closed and the steam so used expansively passes through
port and branch I to the exhaust passage E simultaneously with the inlet of
a fresh charge of steam by the port C for a new power stroke of the piston B.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what
I claim is:-
An engine cylinder with a branch port I from the usual port 1 at the
steam expansion side in combination with a slide valve having a through port H
as specified.
!
1000
R. CORE GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said Alfred John Balkwill.