An Improved Form of Slide Valves for Steam Engines.
Year: 1894

page_text: Date of Application, 7th Dec., 1894
Complete Specification Left, 13th Aug., 1895-Accepted, 28th Sept., 1895
PROVISIONAL SPECIFICATION.
An Improved Form of Slide Valves for Steam Engines.
CECIL ROBERT BOSWELL 76 High Street Dartford Kent Apprenticed
Engineer I do hereby declare the nature of this invention to be as follows:-
Two metal rings which fit round the outside of the cylinder in a steam engine,
onc at, or near, each end, and connected to each other by means of metal rods.
In my drawings
Figs. 1 & 2 are an end & side elevation respectively of the slide valve.
Figs. 3 & 4 are an end & side elevation respectively of the slide valve in position
on a plain cylinder.
Fig. 5 is a longitudinal section of a horizontal steam engine cylinder, showing
how the valve is fitted to it.
Fig. 6 has the left hand half an end elevation with the cylinder cover removed &
the right hand half a section through the centre of the cylinder.
The construction of the slide valve is clearly shown in Figs. 1 & 2 where A are
the two metal rings & B the metal rods.
The way in which it is placed on a cylinder is shown in Figs. 3 & 4, a portion
of one ring being removed in Fig. 4 so that the cylinder ports through which the
steam enters & leaves, may be clearly seen. The valve is worked by being moved
backwards & forwards along the cylinder, so that the ports may be opened to
steam or exhaust at the proper time; the movement may be obtained by eccentrics
or any other suitable means; two or more valve spindles may be necessary however,
in order to impart a smooth & steady motion to the valve; two spindles are shown
in the drawings at C.
In order that the steam may not escape past the valve from the passages D₁ or D₂,
Figs. 5 & 6, to the exhaust chamber E (or the reverse, in the 2nd arrangement of
the valve hereinafter described) without entering the cylinder, the rings of the
valve are made to fit round the cylinder exactly & may have one or more joints
with suitable means of adjustment. By this means the steam will be prevented
from passing the inner side of the ring, that is between the ring of the valve & the
cylinder; & in order that the steam may not escape past the valve on the outer
side of the valve ring, it is surrounded by another metal ring F, Fig. 5, having
suitable means of adjustment so that it may fit exactly round the valve ring. The
ring F is held firmly between the flange G & the metal ring H the latter being
similar to a junk ring in a piston & fastened down by set bolts screwed into the
casting at J, or any other suitable means.
The slide valve may be arranged to work in two ways.
1st. As is supposed to be the case in the drawings, the steam may enter the
steam chest K through the opening L & flow along the passages D₁ & D₂; after
having been used in the cylinder it will flow through the exhaust chamber E & out
through the opening M.
2nd. With a slight alteration of the position of the rings A with regard to
the steam ports in the cylinder, the steam may enter the chamber E through
the opening M; after having been used in the cylinder it will flow through the
passage D, or D2, & the chamber K, & out through the opening L.
Dated this 6th day of December 1891

page_text: 1, CECIL ROBERT BOSWELL 76 High Street Dartford Kent Apprenticed
Engineer do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :----
Two metal rings which fit round the outside of the cylinder in a steam engine,
one at, or near each end & connected to each other by means of metal rods.
In my drawings left with the Provisional Specification
Figs. 1.& 2 are an end & side elevation respectively of the slide valve.
Figs. 3.&.4 are an end & side elevation respectively of the slide valve in position
on a plain cylinder.
Fig. 5 is a longitudinal section of a horizontal steam engine cylinder showing
how the valve is fitted to it.
Fig. 6 has the left hand half an end elevation with the cylinder cover removed
& the right hand half a section through the centre of the cylinder.
The construction of the slide valve is clearly shown in Figs. 1 & 2 where A are
the two metal rings & B the metal rods. The way in which it is placed on a
cylinder is shown in Figs. 3 & 4, a portion of one ring being removed in Fig. 4 so
that the cylinder ports through which the steam enters & leaves may be clearly
seen. The valve is worked by being moved backwards & forwards along the
cylinder, so that the ports may be opened to steam or exhaust at the proper time ;
the movement may be obtained by eccentrics or any other suitable means; two or
more valve spindles may be necessary however in order to impart a smooth &
steady motion to the valve; two spindles are shown in the drawings at C.
In order that the steam may not escape past the valve from the passages D, or D₂
Figs. 5 & 6, to the exhaust chamber E (or the reverse, in the 2nd arrangement
hereinafter described) without entering the cylinder, the rings of the valve are
made to fit round the cylinder exactly & may have one or more joints with suitable
means of adjustment in order that the rings may fit more tightly round the cylinder,
by chis means the steam will be prevented from passing the inner side of the ring,
that is between the ring of the valve & the cylinder & in order that the steam may
not escape past the valve on the outer side of the valve ring, it is surrounded by
another metal ring F, Fig. 5, having suitable means of adjustment so that it may
fit-exactly round the valve ring. The ring F is held firmly between the flange G
& the metal ring H, the latter being similar to a junk ring in a piston & fastened
down by set bolts screwed into the casting at J or any other suitable means.
The slide valve may be arranged to work in two ways.
1st. As is supposed to be the case in the drawings, the steam may enter the
steam chest K through the opening L & flow along the passages D, & D₂; after
having been used in the cylinder it will flow through the exhaust chamber E & out
through the opening M.
2nd. With a slight alteration of the position of the rings A with regard to
the steam ports in the cylinder, the steam may enter the chamber E through
the opening M; after having been used in the cylinder it will flow through the
passages D, or D, & the chamber K & out through the opening L.
Having now particularly described & ascertained the nature of my said inven-
tion, & in what manner the same is to be performed, declare that what I
claim is:
1. The fact of having a slide valve which extends round the outside of the
cylinder

page_text: 2. The fact of having a slide valve which is practically a hollow piston slide
valve the interior of which is filled by the cylinder itself.
3. The fact of utilizing the outside circumference of the cylinder of an engine,
in order that a slide valve of large capacity may be used without occupying much
space.
Dated this 10th day of Avant 1905
CECIL R. BOSWELL.