Improvements in or relating to Valves for Engines, Pumps and the like.
Year: 1897

page_text: Date of Application, 16th Mar., 1897
Complete Specification Left, 7th July, 1897-Accepted, 2nd Oct., 1897
PROVISIONAL SPECIFICATION.
Improvements in or relating to Valves for Engines, Pumps and
the like.
A communication from MORITZ HOCHWALD, Engineer of 30 Calvinstrasse, Berlin,
N.W. in the Empire of Germany.
I, ALFRED JULIUS BOULT of 111 Hatton Garden in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention to be as
follows:-
The present invention relates to improvements in slide valves. These improve-
ments have for their object to obtain a multiple opening for admission and
multiple opening for exhaust, the result of this arrangement being, first, that the
valve-travel is reduced and, second, that the speed with which the ports are opened
and closed, is increased. At the same time the invention has for its object to give
to the slide-valve such a form so that the surface of the slide-valve, exposed to
pressure is as small as possible and equilibrium of pressure is obtained behind
and in front of the piston when the valve is in its central position.
Although there is, as usually, only one port for each side of the cylinder, the object
of the present invention is attained by providing the valve on its face with several
slots or openings which it brings at each stage of opening over the cylinder-ports,
whereupon a multiple admission or multiple exhausting takes place, according to
the position of the valve.
The valve may be either an ordinary slide-valve or a piston or a rotary-valve,
and may be used for a motor-cylinder (steam-engines, compressed-air motor and
the like) as well as for driven cylinders (air-pumps and the like). These valves
also may be provided with outer admissions, as is usual in ordinary slide-valves of
steam-engines, or with inner admissions as in some piston valves.
In one form of the invention the cylinder ports lead the steam to and from the
cylinder ends in the well-known manner. The exhaust ports are in open com-
munication with each other. A central recess in the cylinder is always in
communication with the valve-chest. Each half of the slide-valve which are
coupled together serves both for admission and exhaust of its respective half of
the cylinder and is provided besides its usual valve with an additional U-shaped
port, one of the openings of which at each period of the movement of the valve
is always in communication with the cylinder-ports, the second orifice being closed
when the valve is in the central position by a wall between the exhaust ports,
and admitting steam into the cylinder through the central recess during the move-
ment of the valve in one direction, while during the movement of the valve in
the opposite direction it places the exhaust port in communication with the
exhaust. In this way the valve which admits the steam and enables it to escape
in the usual manner, receives in each opening position a second admission or
exhaust, thus doubling the cross-sectional area of the passage for admission as
well as for exhaust so that the usual amount of opening is obtained with about
half the extent of travel necessary with an ordinary valve.
A further modification consists of a slide-valve which differs from the previous
one by the ordinary valve cavities being always in communication with each other
through a passage in the valve. In this way the admission is not altered in any
way but the method of exhausting is different. The exhaust takes place, say

page_text: from the port when the valve moves towards the left on one hand through both
passages, so that two co-operating exhaust passages need be only half as wide as
in the previous cases. Thus the surface of the valve exposed to steam-pressure
and consequently also the work expended to overcome friction is reduced.
A further modification consists in forming "the walls of the ordinary valve
chambers with laps or flanges to cover the exhaust ports.
The object of this construction is to increase the bearing surface of the slide-
valve.
Another object of the additional flange is that the distance between the edges of
the inner walls of the trick passages being made greater than the distance between
the inner edges of the steam ports of the cylinder. The result of this will be
that when the valve is in its central position, the two sides of the cylinder com-
.municate with each other through the valve, in consequence of which the pressure
on both sides becomes the same. This property of the valve may be utilised in
steam-engines to increase compression when the engine has to do much work and
to reduce it when the work to be done decreases.
In another modification the valve-laps or flanges covering the exhaust ports
being provided with cavities which act in exactly the same manner as the cavities
of an ordinary slide-valve; by this arrangement a third exhaust opening is created.
The three valve-ports on one side, and the three valve-ports on the other side are
equal to each other, and the treble exhaust from the cylinder port begins to take
place, as soon as the edge of the valve comes to lie over the edge of the port-face,
for at the same time the other ports also come into communication.
Each of the valves described may be also provided with an expansion-valve.
The valve may be provided with a Trick-passage, thus creating a third admission
opening.
Each valve of the present construction provided with a Trick-passage, can
receive steam from the recess in the centre of the port-face through an auxiliary
passage leading from the Trick-passage down to the port-face, the orifice of said
passage resting in the central position of the valve on a bar which divides the
recess into two parts.
1
When the valve moves in one direction the Trick-passage is placed in double
communication with the valve-chest so that the two steam ports are connected in
turn with the valve-chest by four steam-passages.
1
1001
BOULT & WADE,
Agents for the Applicant.
Improvements in or relating to Valves for Engines, Pumps and
the like.
A communication from MORITZ HOCHWALD Engineer of 30 Calvinstrasse, Berlin
N.W. in the Empire of Germany.
i
I, ALFRED JULIUS BOULT of 111 Hatton Garden in the County of Middlesex,
Chartered Patent Agent, 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 present invention relates to improvements in slide valves. These improve-
ments have for their object to obtain a multiple opening for admission and
multiple opening for exhaust, the result of this arrangement being, first, that the

page_text: valve travel is reduced and, second, that the speed with which the ports are opened
and closed is increased. At the same time the invention has for its object to give
to the slide-valve such a form that the surface of the slide valve exposed to
pressure is as small as possible and equilibrium of pressure is obtained behind
and in front of the piston when the valve is in its central position.
Although there is as usually only one port al a³ for each side of the cylinder the
object of the present invention is attained by providing the valve on its face with
several slots or openings which it brings at each stage of opening over the cylinder
ports whereupon a multiple admission or multiple exhausting takes place according
to the position of the valve.
The valve may be either an ordinary slide valve or a piston or a rotary valve
and may be used for a motor cylinder (steam engines compressed air motor and
the like) as well as for driven cylinders (air pumps and the like). These valves
may also be provided with outer admissions as is usual in ordinary slide valves
of steam engines or with inner admissions as in some piston valves.
Figs. 1, 1 are longitudinal and cross sectional views respectively of a slide
valve of a steam engine with outer admission. The valve is shown in its central
position; in one form of the invention the cylinder ports a¹ a lead the steam
to and from the cylinder ends in the well known manner. The exhaust ports b¹ b²
are in open communication with each other in the construction illustrated in the
drawing. A central trough like recess in the cylinder is always in communica-
tion with the valve chest. The slide valve is divided into two valve m¹ m² and
each side of the valve is provided with an auxiliary U-shaped or curved port a
one of the openings of which at each period of the movement of the valve is always
in communication with the cylinder ports a a² the second opening being closed
when the valve is in the central position by a wall between the exhaust ports
and admitting steam into the cylinder through the central recess c during the
movement of the valve in one direction while during the movement of the valve in
the opposite direction it places the port 61 62 in communication with the exhaust.
In this way the valve which admits the steam at the edges 6 and 1 and enables
it to escape at the edges 9 and 2 in the usual manner receives in each opening
position a second admission or exhaust thus doubling the cross sectional area of
the passage for admission as well as for exhaust so that the usual amount of
opening is obtained with about half the extent of travel necessary with an ordinary
valve.
Figure 1 shows such a piston valve in its extreme left hand position.
Fig. 2 is a longitudinal section and Fig. 2 a cross section on the lines a
and y y of a slide valve which differs from the previous one by the ordinary valve
cavities m¹, m³, being always in communication with each other through the
passages in the valve. In this way the admission is not altered in any way but
the method of exhausting is different. The exhaust takes place say from the
port al when the valve moves towards the left on one hand through passages a', k₁, bl
on the other hand through passages a¹, m³, 1, m², 63. Owing to the shape of
the valve the co-operating exhaust passages b1, b2, need be only half as wide as in
the previous cases Figures 1 1* 1* Thus the surface of the valve exposed to
steam pressure and consequently also the work expended to overcome friction is
reduced.
The only difference between Figs. 2 and 3 is that in the latter the parts d³, d³,
forming the walls of the valve chambers m', m² are provided with laps or flanges
to cover the exhaust ports b', 2. Thus the exhaust takes place say for a¹ at the
edges 11 and 4, as well as at 10' and 3¹, while in Fig. 2 this was effected at the
edges 11 and 4, and 9 and 2. The object of this construction is to increase
the bearing surface of the slide valve.
Another very important object of the additional lap will become apparent on
examining Fig. 4. This Figure differs from Fig. 3 in the distance between the
edges 9, 91, on the inner walls of the trick passages being greater than the distance
between the edges 2, 21, of the steam ports of the cylinder. The result of this will be

page_text: that when the valve is in its central position the two sides of the cylinder com-
municate with each other through the valve in consequence of which the pressure
on both sides will be the same. This property of the valve may be utilized in steam
engines to increase compression when the engine has to do much work, and to
reduce it when the work to be done decreases.
Figs. 5, 5, 5, differ from Fig. 4 by the valve laps or flanges covering the exhaust
ports b¹, b, being provided with cavities p¹, 73, which act in exactly the same
manner as the cavities of an ordinary slide valve; by this arrangement a third
exhaust opening is created. The three valve ports 12 to 2, 11 to 4, and 10 to 3¹,
on one side, and the three valve ports 121 to 2, 11' to 41, and 10 to 3, on the other
side are equal to each other and the treble exhaust from say the cylinder port a¹
begins to take place as soon as the edge 12 of the valve comes to lie over the edge 2
of the port face for at the same time 11 is situated over 4 and 10' over 3'. Fig. 5
shows this valve in its central position Fig. 5^ being a cross section on the line r
and yy and Fig. 5 a section showing it in the position in which admission takes
place at the left and exhaust at the right hand end of the cylinder.
The cavities p, 23, could be connected with each other by means of passages
in the valve in similar way to the cavities m¹ m² whereby the length of the slide
would become smaller than that of the valve shown in Figs. 5 and 5* in which
such connection does not exist. These passages can be arranged so that they do
not open at the same time as the other two passages for exhaust, as in the example
illustrated, but successively.
Fig. 9 shows a slide valve in central position which is adapted from a valve
according to Fig. 4, by providing each of the auxiliary passages or with
branch passages with orifices 16, 17, or 16' 171, passing through the valves m¹
or m³. At the same time the outlet ports are provided with a second orifice 18, 19,
or 18 19¹, on the slide surface.
It will be seen that the slide valve is also provided with the slots already
mentioned with reference to Fig. 4, so that the edge 2, or 21, of the valve at the
beginning of the exhaust has already opened to an extent equal to the width of
the slot 2-9, or 21-91, plus the exhaust lap. In the drawing this amount is made
equal to of the width of the port.
If this valve is moved from its central position towards the left-hand side, to
the extent equal to the exhaust-lap, then the edge 16 of the valve stands over the
edge 19, and edge 11 over the edge 4, and thus owing to the co-operation of the
auxiliary passage with the outlet 6' there are formed two exhaust passages.
At the same time, however, the edges 10', or 20', of the valves m³ will be over
the edges 31, or 18', of the cylinder, and therefore, owing to the co-operation of
the exhaust-passage m³, 1 m³, with the exhaust port 62, there are formed two more
exhaust passages. The latter two passages will remain, owing to the supposition
made for the lead of the edge 2, until the valve has moved the distance s,' i.e., equal
to the exhaust-lap + width of port, as four exhaust passages are simultaneously
formed until the maximum opening for exhaust is attained. This position of the
valve is shown in Fig. 9. The dimensions with regard to exhaust are chosen
in the drawing so that this maximum width of opening for exhaust attained by
one movement is maintained constant until the valve comes into the end position
shown in Fig. 9. When the valve has reached the latter position, it begins to
return, and the exhaust still remains fully open until the valve has returned
into the position shown in Fig. 9, from which time quick closing of the port
takes place.
This valve therefore opens the exhaust suddenly and maintains it fully open
for a very long time, so that the steam pressure falls quickly and the exhaust takes
place in a very favourable manner.
Fig. 9 is a longitudinal section through the connecting passage on the
line y-y, and Fig. 9° a cross-section on the line --.
The widening of the opening of the cylinder-port necessitated by the lead of
the edge 2 or 21 as well as by the thickness of the wall 8-9, or 81-9', results

page_text: in a slight increase of clearance. By arranging an intermediate wall this increase
can be avoided. This is especially advisable when the valve is formed as a
circular valve. The action of the valve itself will be in no way influenced by such
an additional intermediate wall in the orifice of the cylinder-port.
Each of the valves described may be also provided with an expansion-valve.
Fig. 6 illustrates such arrangement for the valve shown in Fig. 2.
Fig. 7 shows a valve (Fig. 2) with a Trick-passage, thus creating a third admis-
sion opening. This passage may be of course also used in the construction of
valves according to Figs. 13, 4 and 5.
Each valve of the present construction provided with a Trick-passage t can
receive steam from the recess c in the centre of the port-face, through an auxiliary
passagen, leading from the Trick-passage down to the port-face, the opening of
said passage n resting in the central position of the valve on a part r, which divides
the recess into two parts c³ ³.
Figs. 8 and 8 show such a construction of the Trick passage.
When the valve moves into its right-hand position, the Trick-passage t is placed
in double communication with the valve-chest by passages c², n, as well as 131, 141, t³
for the port t, t', a', and when the valve moves towards the left the Trick passage
is placed in communication with the valve-chest for the port t, t, a², through
passages c¹, n, as well as 15, 14, t¹. In this way a¹ as well as a³ are connected in
turn with the valve chest by four steam-passages, viz:-
cdn t t¹ a¹
ck al
15 14¹¹ a¹
6, 1, a¹
or
cln t ta aª
c² k³ aª
15, 14, t¹tt a³
61, 1¹, a³
Having now particularly described and ascertained the nature of this in-
vention as communicated to me by my foreign correspondent and in what
manner the same is to be performed I declare that what I claim is:-
1. A slide valve provided with chambers as m¹ m², longitudinal passage, as 1, for
connecting said chambers, and auxiliary passages, as 2, in combination with
the valve face of a cylinder with admission ports, as a¹ a², exhaust ports, as 61 62,
and a cavity c in the path of the slide valve, substantially as described.
2. A slide valve provided with chambers m¹, or m², trough-like cavities, as p¹, p³,
in the valve laps covering the exhaust ports, longitudinal passages for connecting
the chambers m¹ m² with the auxiliary passages or 2, in combination with the
face of a cylinder, with admission ports as a¹ a², exhaust ports as 162, and cavity c
in the path of the slide valve, substantially as described.
3. A slide valve provided with chambers, as m¹ m², longitudinal passages, as 1,
for connecting these chambers, auxiliary passages, or 2, with branch
passages 16-17, or 161-171, passing through the chamber m' m², in combination
with the cylinder face having admission ports, as a a², exhaust ports, as 61 62,
and a cavity, as c, in the path of the slide valve, substantially as described.
4. In combination with slide valves of the character described, the arrangement
of a trick passage which can co-operate with the cavities c¹ c² in the valve face by
a central branch passage n substantially as described.
5. The combination and arrangement of parts constituting the complete slide
valve apparatus substantially as described and illustrated in Figure 1, or in
Figure 2, or in Figure 3, or in Figure 4, or in Figure 5, or in Figure 6, or in
Figure 7, or in Figure 8, or in Figure 9, of the accompanying drawings.
BOULT & WADE,
Agents for the Applicant.