Improvements in the Valves of Steam and other Fluid Pressure Engines.
Year: 1898

page_text: Date of Application, 26th Feb., 1898
Complete Specification Loft 26th Nov 1898 Accented 21st Jan
1899
Improvements in the Valves of Steam and other Fluid Pressure
Engines.
I, JOHN WILLIAM MELLING, of 82, Swinley Road, Wigan, in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in double faced tapered slide valves
employed in steam and other fluid pressure engines and my improvements consist
in combining and fitting such slide valves with cut off or expansion valves
actuated independently of the main valve in any suitable and convenient way
for the purpose of cutting off and regulating the supply of steam or other elastic
fluid to the cylinder. These expansion valves might have parallel faces but I
prefer to employ expansion valves with tapered faces for convenience of adjust-
ment. Also I give a double admission so that the pressure of steam or other
elastic fluid on one end or face is perfectly balanced and counteracted by the
pressure on the opposite end or face.
H. B. BARLOW & GILLETT,
Agents for Applicant.
COMPLETE SPECIFICATION.
Improvements in the Valves of Steam and other Fluid Pressure
Engines.
I, JOHN WILLIAM MELLING, of 82, Swinley Road, Wigan, in the County of
Lancaster, 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:-
My invention relates to improvements in double faced tapered slide valves
employed in steam and other fluid pressure engines and my improvements consist
in combining and fitting such slide valves with cut off or expansion valves
actuated independently of the main valve in any suitable and convenient way
for the purpose of cutting off and regulating the supply of steam or other elastic
fluid to the cylinder. These expansion valves might have parallel faces but I
prefer to employ expansion: valves with tapered faces for convenience of adjust-
ment. Also I give a double admission so that the pressure of steam or other
TD 017

page_text: elastic fluid on one end or face is perfectly balanced and counteracted by the
pressure on the opposite end or face.
In the accompanying six sheets of drawings-
Figure 1 is a side elevation partly in section, Figure 2 is a plan partly in
section and Figure 3 is a transverse vertical section, taken on the plane of the
line AB, Fig. 2, of a pair of double faced tapered slide valves each of which is
fitted with a cut off or expansion valve according to my improvements.
Figures 4, 5 and 6 are similar views to Figs. 1, 2 and 3 respectively of a single
double faced tapered slide valve fitted with a pair of cut-off or expansion valves
according to my improvements.
Referring first to Figures 1, 2 and 3, in these views, 1 denotes the cylinder,
2 the piston, 3 the two valve boxes one near each end of the cylinder, 4 the main
double faced tapered slide valve which admits steam through the ports 5 to the
ports 6 and so to the cylinder 1. The main valve 4 is fitted with a sliding cut-
off or expansion valve 7 through each end of which steam flows and enters the
main valve ports 5, and exhausts through the main valve ports 8 into the cylinder
exhaust passages 9, which lead to the main exhaust passage 10, see Fig. 2. The
fresh steam is supplied to the main steam chest through a pipe not shown con-
nected to the port 12.
The cut-off valves 7 (one of which is applied to each main valve 4) may be of
any suitable type of slide valve but I prefer to employ valves with tapered faces
for convenience of adjustment and these cut-off valves may be operated by any
suitable means but prefer to actuate them as illustrated in Fig. 1 where 13
denotes a reciprocating bar, 14 a three armed lever pivoted thereon, 15 connecting
rods, 16 rocking levers, 17 connecting rods and 18 valve rods of the cut-off
valves 7, which therefore receive a regular reciprocating motion from the bar 13.
The remaining arm of the three armed lever 14 is connected by a rod 19 to the
governor or other regulator which can thereby vary the relative positions of the
cut-off valves 7 to each other and to the main valves 4 according to requirements
of the load.
Referring now to Figures 4, 5 and 6, in these views, 1 denotes the cylinder,
2 the piston, 3 the valve box, 4 the main double faced tapered slide valve, 5 the
valve ports, 6 the cylinder ports, 7 the cut-off valves which receive a reciprocating
motion from the bar 13, system of three levers 14 (which correspond to the three
armed lever 14 in Fig. 1) connecting rod 15 to one cut-off valve rod 18 and con-
necting rod 15, rocking lever 16 and connecting rod 17 to the other cut-off valve
rod 18. The system of levers 14 is connected by the rod 19 to the governor or
other regulator which controls the relative position of the cut-off valves to one
another and to the main valve. For example, if the governor raises its connected
lever 14 to the highest position the cut-off valves 7 which are shown in mid-
position are drawn farther apart into the position that would give the latest cut-off
but if the governor put the connected lever 14 into the lowest position the cut-
off valves would be moved nearer together and would cut off steam at the earliest
part of the stroke.
Instead of employing two cut-off valves 7 in combination with a single double
faced tapered slide valve as illustrated in the arrangement Figs. 4, 5 and 6, I
might employ only a single cut off valve with double ports and actuate such valve
by means of a trip gear or other suitable valve gear in place of the means herein
shown and described.
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 combination with each double faced tapered slide valve, of a cut-off or
expansion valve actuated independently of the main valve substantially as and

page_text: 2. The combination with a double faced tapered slide valve, of a pair of cut-off
or expansion valves or one such valve with double ports actuated independently
of the main valve substantially as and for the purposes herein described and as
illustrated by ligs. 4, 5 and 6.
1000
H. B. BARLOW & GILLETT,
Agents for Applicant,
17. St. Ann's Square, Manchester.