IMPROVEMENTS IN SLIDE VALVES FOR STARTING, STOPPING, AND REVERSING STEAM AND OTHER ENGINES AND MACHINERY
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by Andrew Betts Brown at the
Office of the Commissioners of Patents, with his Petition, on the
25th September 1871.
I, ANDREW BETTS BROWN, of 80, Cannon Street, London, in the
County of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SLIDE VALVES FOR STARTING, STOPPING, AND REVERSING
STEAM AND OTHER ENGINES AND MACHINERY," to be as follows:-
This Invention has for its object improvements in slide valves and
details mainly applicable to the apparatus for which Patents were
granted to me, bearing date 8th January, 1869, No. 61, and 7th
April 1870, No. 1018.
In the Specifications of the said Inventions I have already described
the means by which I obtain a pressure of water by an automatic
pumping apparatus, and also the machinery employed for steering
and for working heavy steam and other engines. In such machinery
I have employed a slide valve of usual construction (as in the steam.
engine) having two admission ports and one central exhaust port, and

page_text: I describe in the Specification of my said Patent No. 1018, 1870, a
subsidiary slide valve which worked upon the back of the main slide
valve for the purpose of controlling the movement of the tiller with the
hydraulic cylinders which actuate it. This arrangement I have found
to be in practice so far imperfect, there being two working faces, and
the arrangement which I will now describe dispenses with the use of
the second, or subsidiary slide valve.
When a valve constructed in accordance with my Invention is applied to
reversing engines it is so arranged that when in the centre of its stroke
it covers the two admission ports. When it is moved in either direction
it will admit water to or from either of the reversing cylinders applied
for actuating the weigh shaft. The spindle which works this valve
passes through both ends of the valve casing, and inside the casing it
has a screw of single or double thread formed upon it. This screwed
part of the said spindle works in a corresponding nut, which is fixed
on the back of the slide valve. At one end of the said valve spindle
is placed the reversing wheel, which when turned by the attendant
causes the said spindle to revolve (jointed levers may be used instead
of the screw above described), the other or opposite end has a swivel
joint, which is connected by a rod to a small crank pin on the weigh
shaft or to a shaft receiving its motion from it. By this means the
motion given to the slide valve by the turning of the reversing wheel
in the direction of opening the admission port, is counteracted by the
valve spindle being pushed endways in the direction of closing the
admission port by the crank pin on the top of the weigh shaft. In
this manner the water admitted to the reversing cylinders by the slide
valve is automatically cut off at any point of the stroke of these
cylinders. When it is desired to stop, start, or reverse large engine
valves by hand power, I form in the back of engine slide valve a
cylinder having a valve face with two admission ports, one exhaust;
upon this face my improved slide valve works. The cylinder is fitted
with a stationery piston, so that when the valve moves in either
direction the cylinder moves, and with it the valve face which counter-
acts the motion given to the valve and shuts the admission ports.
Although I have described my said slide valves applied to reversing
apparatus, it will be obvious they are equally applicable arranged in the
same manner for steering engines and other machinery actuated by the

page_text: The accompanying Sheet of Drawings shews a modification of my
improved valve, where A is the valve face; B, the slide valve; C, the
screwed spindle; D, the nut; E and F, the pipes leading to reversing
cylinders; G, swivel of valve spindle; H, the reversing wheel; I, the
weigh shaft moved by the reversing cylinder; J, the crank pin; K, the
cut-off or connecting rod.