Improvements in Slide Valves.
Year: 1890

page_text: Improvements in Slide Valves.
I, GUSTAV DUVINAGE, Engineer, of Pasewalk in the Kingdom of Prussia and
German Empire 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 :-
The hereinafter described invention refers to a cylindrical three-ported slide-valve,
and the object of the invention is to construct a slide valve which shall be almost
entirely relieved of steam pressure.
The invention is illustrated in the accompanying drawings.
Fig. 1 shows in cross section the almost entirely relieved cylindrical three-ported
slide-valve with its casing and the steam cylinder belonging to it.
Fig. 2 is a longitudinal section of fig. 1.
Fig. 3 is a plan view of the cylindrical three-ported slide-valve.
Fig. 4 shows to a smaller scale a modification of the valve.
The new three-ported slide-valve A forms a cylinder, enclosed in a cylindrical case
and having a slot or opening s cut along its entire length at the top or side opposite to
the exhaust port G, (see figs. 1 and 3) The valve, as usual, possesses at its under-
side a chamber y.
Instead of the chamber having the usual flat working surface it
has, of course, since the valve is of cylindrical shape, a curved working surface.
The working surface has, as usual, an outer cover or lap H and inner cover or
lap j.
By walls Z, Z arranged lengthwise along the cylinder the slide-valve is divided
into divisions, namely the division or chamber y already mentioned, and the
divisions x.
The latter allow a free passage of steam through the slide valve and
admission to both sides so that the valve is balanced.
The upper divisional walls Z' Z' serve to stiffen the cylindrical body of the slide-
valve. The upper slit S in the cylindrical body of the slide-valve is for giving a
certain amount of spring or elasticity to the valve body so that it may fit close
against the interior of the slide-valve casing. The pressure of steam on the slide-
valve depends on the width of the slit S.
The steam enters the slide valve casing B through the opening C, passes through
the valve so as to have steam pressure at each end and balance the valve; and, as the
valve is moved backwards and forwards, enters by the steam supply ports D and F
to the cylinder E as usual. The exhaust steam passes off through the port G.
In the modification shown at fig. 4 there are only two dividing walls Z instead of
four as in fig. 1 and consequently only one division or steam spacer.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is-
An almost entirely relieved three-ported slide-valve characterised by a cylindrical
valve, which is enclosed in a cylindrical slide-valve casing and has a curved working
surface, the chamber y of the valve being separated by dividing walls Z from the
steam space or spaces and the valve, opposite its working surface, being slit length-
wise in order that it may fit close against the interior of the slide valve casing,
substantially as hereinbefore described and shown on the drawings annexed.
Dated this 14th May 1890.
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.