Improvements in Engine Slide Valves.
Year: 1899

page_text: Date of Application, 16th May, 1899
Complete Consification Loft 16th Fob 1000 Accented 24th Mor
1000
Improvements in Engine Slide Valves.
I, REUBEN THOMAS PRESTON, of Hayes Court, Hayes, Kent, Engineer, do hereby
declare the nature of this invention to be as follows:-
The object of these improvements in slide valves is to provide a means of
ascertaining when the face of same is worn down as far as it is safe and to prevent
the breaking when worn down too thin in the face part. For this purpose I form
holes recessed into the valve from the back near the inner edges of the hollow of
the valve to within such a distance of the face as it is desired the face to wear to
before replacing the valve by a new one. These holes are in such places that the
steam or other pressure fluid, when the face is worn so far, will blow through
from the pressure side to the exhaust side and by the whistling sound thus
produced call the driver's attention to the fact that the valve is worn out and
needs replacing. Assuming for instance that the valve shall not be allowed
to wear thinner than half an inch without giving warning, then I drill the
holes or recesses or otherwise form them so deep as to reach to within half an inch
of the face.
As an alternative or combined with the aforesaid holes I form the lateral
flanges of the valve with edge recesses to the width and depth required and by
preference two or more such recesses of half round notch form, whereby the
strength of the valve is not sensibly weakened and thus by anticipation "lead
or steam admission bringing a retarding influence to bear which at once suggests
to the driver that something is wrong with the slide valve.
"
The invention is applicable to D shaped and other slide valves and is of special
advantage in locomotive and marine engines.
I, REUBEN THOMAS PRESTON, of Hayes Court, Hayes, Kent, 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:-
دو
The object of these improvements in slide valves is to provide a tell-tale
means of ascertaining when the face of a valve is worn down as far as is safe
and thus to prevent the breaking which often takes place when the valve has
[DQ77

page_text: worn too thin. For this purpose I form holes or recesses from the back
of the valve near the inner edges of the hollow of the valve to within such a
distance of the face as it is desired to allow the face to wear before replacing the
valve by a new one or as an alternative or in combination with such firstly
described holes or recesses 1 form the valve with recesses at one edge or edges to
the width and depth required. These holes or recesses are in such places that
the steam or other pressure fluid will, when the face is worn so far, blow
through from the pressure side to the exhaust side and, by the whistling sound
thus produced, call the driver's attention to the fact that the valve is worn out
'and needs replacing.
Figure 1 of the accompanying drawings is an elevation of a slide valve con-
structed according to this invention.
Figure 2 is a plan thereof partly in section.
Figure 3 is an inverted plan of a modification.
Figure 4 is a cross section on the line X-Y Figure 3 and
Figure 5 is a plan.
Referring to Figures 1 and 2 it will be seen that the valve A is provided with
holes or recesses B indicated in dotted lines in Figure 1 and in full lines in the
plan view Figure 2. These holes B are in such places that the steam or other
pressure fluid will blow through from the pressure side to the exhaust side when
the face of the valve is worn so far and as the steam or the like escapes a
whistling sound will be produced which will call the attention of the driver or
attendant to the fact that the valve is worn out, or is worn as thin as is consis-
tently safe, and needs replacing. Assuming for instance that the valve shall not
be allowed to wear thinner than half an inch without giving warning, then the
holes or recesses B are drilled or otherwise formed of such a depth as to reach
within half an inch of the face of the valve. It is evident that the whistling sound
may be increased by applying a metal musical reed or the like to the hole.
As an alternative or combined with the aforesaid holes the flanges A¹ of the
valve are as shewn in Figures 3, 4 and 5, provided with four recesses B¹ at the
edge to the width and depth required. Instead of four recesses there may be less
or more but by preference there are at least two of such recesses. I do not confine
myself to the particular form of recesses shewn as other forms may be used
without departing from the invention, but in any case care must be taken that
the strength of the valve is not sensibly reduced by the recesses made therein.
By this means when the valve face is worn to such an extent that one or more
of the recesses B₁ affords or afford a passage through for the steam an anticipatory
lead or steam admission will ensue thus bringing a retarding influence to bear
which will at once suggest to the engine driver or attendant that something is
wrong with the slide valve. The particular construction just referred to is also
provided with holes B2 of the kind hereinbefore described and referred to by the
letter B in Figures 1 and 2.
The invention is applicable to D shaped and other slide valves and is of
special advantage in locomotive and marine engines.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is;
1. The application and use in a slide valve of a
as set forth.
"tell-tale" device substantially
2. The application and use in a slide valve of holes or recesses extending to
within a predetermined distance from the face of the valve for the purpose
specified.
and
3. The application and use in a slide valve of holes' recesses in the back
ог
of the valve and extending to within a certain distance from the face of the valve
substantially as set forth.

page_text: 4. A slide valve provided with holes in the back substantially as and for the
purpose set forth and shewn in Figures 1 and 2 of the drawings.
5. A slide valve provided with recesses in the edge or edges of the valve with
or without the holes B2 in the back of the valve substantially as and for the purpose
set forth and shewn in Figures 3, 4 and 5 of the drawings.
1
Ը Wa
1000
JENSEN & SON,
77, Chancery Lane, London, W.O., Patent Agents.