Improvements in and relating to Steam Engines.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in and relating to Steam Engines.
I, WILLIAM HUGGINS, of 20, Forest Park Road, Dundee, in the County of
Forfar, Scotland, Patternmaker, do hereby declare the nature of this invention
to be as follows:-
-
This invention relates to improvements in steam engines, the object being to
control the supply of steam to the cylinder in a new and improved manner so
that the clearance space may be reduced to a minimum, and also to simplify the
mechanism for actuating the valves and the parts relating thereto by making
each cover with its steam chest, valves and appurtenances selfcontained.
In carrying out my invention I preferably employ eccentrics, trip gear and
dash pots of the type used in connection with Corliss valves to actuate my improved
valves, although I do not confine myself to such but may use instead of, or in
addition to such, other known appliances such as cams, levers, toothed racks
and quadrants.
In one modification each end or cover of the cylinder is provided with flat or
disc grid valves which may be in one or two parts. Such disc valves are caused
to partially rotate backwards and forwards about the axis of the cylinder by
suitable mechanism, the openings in the valves and the cover being so arranged
that steam is admitted, cut off and exhausted in the usual manner.
In another modification two segmental grid valves are used for each end, one
to control the admission and the other the emission of the steam to and from the
cylinder, the openings in the valves and the cover being suitably arranged as
previously described. These valves may be so designed as to be wholly, partially
or intermittently balanced, as may be found most suitable.
In some cases instead of causing grid valves at each end of the cylinder to
oscillate about its axis, I may use one or two grid slide valves, such valves being
made to reciprocate by means of suitable mechanism.
To reduce the clearance to the smallest possible amount I may cause projections
on the piston to pass into the steam and exhaust ports when such piston is at the
extremes of its stroke.
T L
101
1000
Improvements in and relating to Steam Engines.
I, WILLIAM HUGGINS, of 20, Forest Park Road, Dundee, in the County of
Forfar, Scotland, Patternmaker, do hereby declare the nature of this invention
[Price 871
1

page_text: and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following stateinent:-
-
This invention relates to improvements in steam engines, the object being to
control the supply of steam to the cylinder in a new and improved manner so
that the clearance space, that is to say the condensing surface, may be reduced
to a minimum, and also to simplify the mechanism for actuating the valves and
the parts relating thereto by making each cover with its steam chest, valves and
appurtenances self-contained.
And in order that my said invention and the manner of performing or carry-
ing the same into effect or practice may be properly understood, I have hereunto
appended three explanatory sheets of drawings in which the same reference
numerals are used to indicate corresponding parts in all the figures where shown,
that is to say:
Figure 1 (Sheet 1) is a cross-section at A A (Figure 4) showing the valve ports
and the cams for actuating the valves.
Figure 2 (Sheet 1) is a view looking on the front of the cylinder and showing
the slide for the cross-head in section.
Figure (Sheet 2) is a section at 13 B (Figure 4) showing the admission and
exhaust valves, the admission valve being closed and the exhaust valve open.
Figure 4 (Sheet 2) is a longitudinal part section of the back portion of the
cylinder.
Figure 5 (Sheet 2) is an external side view of the back portion of the cylinder
looking in the direction of the arrow C (Figure 1).
Figure 6 (Sheet 1) is an enlarged face view of the cam for actuating the
admission valve.
1
Figure 7 (Sheet 1) is an enlarged face view of the cam for actuating the
exhaust valve.
Figure 8 (Sheet 3) is a part section at D 1) (Figure 10) showing a modified
form of cylinder and cover.
Figure 9 (Sheet 3) is a part section showing a section at E D (Figure 10).
Figure 10 (Sheet 3) is a part face view of the valve and cylinder end.
In carrying out my invention I may employ eccentrics and trip and dash pots
of the type used in connection with Corliss valves, although I do not confine
myself to such but may use instead of, or in addition to such, other known
appliances such as cams, levers, toothed racks and quadrants.
In the first modification, illustrated by Figures 1 to 7, which I have taken for
detailed description and illustration, two segmental grid valves 10 and 11 are
used for each end of the cylinder, one to control the admission and the other
the emission of the steam to and from the cylinder 12, the openings 13 in the
valves and the openings 14 in the cover being so arranged that the steam is
admitted, cut off and exhausted in the usual manner. The valves may be so
designed as to be wholly, partially or intermittently balanced, as may be found
most suitable. In this modification, as described later the valves are inter-
mittently and approximately balanced when being moved. The valves are
actuated and operated in the following manner:-
A side shaft 15 is made to rotate by suitable means, such as by a combination
of spur and bevel wheels or by means of bevel wheels alone, such shaft being
actuated by the crank shaft of the engine and made to rotate at the same speed.
On the side shaft is a duplex cam 16 of which one groove 17 governs the admis-
sion valve 10 while the other groove 18 governs the emission or exhaust valve 11.
The admission valve is actuated by a toothed segment 19 and the emission valve
by a similar device 20. The admission segment 19 is fixed to or forms part of a
shaft 21 which is made to partially rotate backwards and forwards by means of
a lever 22, and coupling rods 23, and 24, which in turn are actuated by the
cam 17 and cam roller 25. The emission segment 20 is operated in a similar
fashion by means of the shaft 26, lever 27, coupling rods 28 and 29, cam 18, and

page_text: cam roller 30. The cam for the admission valve is so designed that it opens
such valve to admit steam into the cylinder at the beginning of the stroke in the
usual way and cuts off at any determined portion of the stroke; while the emis-
sion valve may be open for about half the stroke and closed for the other half.
Referring to Figure 6 which shows the admission cam :-
As the cam roller travels relatively from S to T the valve is opening; from
T to it remains open and without motion: from U to V it is closing and
from V to S it remains closed without motion. The emission cami, Figure 7,
opens the valve as the cam roller relatively travels from X to Y; it remains
open from Y to Z: closes from Z to W and remains closed from W to X.
It is to be noted that these valves are intermittently balanced, that is to say
when the admission valve is being opened the steam pressure is about equal on
both its sides because of the terminal compression of the exhaust steam, and it
is also balanced when it is closing to cut off the steam because at that time the
pressure of the steam within the cylinder is about equal to the pressure of the
steam in the steam pipe. The exhaust valve may be similarly balanced by
regulating the terminal pressure relative to that of the atmosphere, or of the
receiver, should such be used. 31 are divisions in the cylinder end for separating
the admission from the exhaust steam, that is to say these divisions form separate
chambers in which the admission and exhaust valves work. The steam pipe
from the boiler is in communication with the aperture 32 and the exhaust steam
pipe with the aperture 33. I do not confine myself to such an arrangement but
may admit and exhaust the steam from the opposite direction, or even through
the cylinder cover 34, in such cases placing the admission and exhaust valves
to suit.
The modification illustrated by Figures 8 9 and 10 is given to show how a
simple type of cover may be applied to a cylinder.
In some cases, instead of causing grid valves at each end of the cylinder to
oscillate about their axis, I may use two grid slide valves, such valves being made
to reciprocate in a straight line by means of suitable mechanism, such as has
been previously described.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is;
(1) In steam engines, the use of separate grid valves for admitting and
emitting the steam to and from the cylinder, substantially as described.
(2) In steam engines, the combination of separate grid valves with cylinders.
and cylinder covers, substantially as described.
(3) In steam engines, the combination of separate grid valves with cylinders,
cylinder covers, and toothed segments, as described.
(4) In steam engines, the combination of separate grid valves with cylinders,
cylinder covers, and toothed segments operated by cams, as described.
(5) In steam engines, the combination of separate grid slide valves with
cylinders and cylinder covers, as described.
(6) The construction, arrangement and combination of parts, substantially
as described.
1011
1
1000
GEO. C. DOUGLAS & Co.,
41, Reform Street, Dundee, Agents for Applicant.