Improvements in Hydraulic Engines for Blowing Organ Bellows or other purposes.
Year: 1892

page_text: Date of Application, 24th Oct., 1892
Complete Specification Left, 19th June, 1893-Accepted, 12th Aug., 1893
PROVISIONAL SPENTATION.
Improvements in Hydraulic Engines for Blowing Organ Bellows
or other purposes.
ALEXANDER MORRIS MELVIN 28 Charles Street, Saint Rollox, Glasgow in
the County of Lanarkshire, Engineer do hereby declare the nature of this invention
to be as follows:-
:-
The object of this invention is to control the motion of the main piston of the
engine at the reversal of its stroke so that no jerking may arise from the sudden
admission of the water through the ports.
And my invention consists in automatically controlling the motion of the main
valve at the time of reversal of the main piston.
This is effected by means of having two pairs of ports near each end of the main
valve casing which are alternately covered by the main valve in its travel. This
main valve is an equilibrium one of the piston type having three or more pistons
for controlling the admission & escape of the water to either end of the main
cylinder.
This main valve is moved backwards & forwards by the water pressure which is
alternately admitted & exhausted at either end of the main valve through passages
communicating with a four way cock or slide valve having its motion derived from
the main piston & which alternately places these passages in communication with
the water pressure & the exhaust. Each end of these passages at the point where
they enter the main valve casing is covered by a check valve which allows the
water to enter but prevents it passing back again. The two pair of ports before-
mentioned have communication between the passages beforementioned & the main
valve casing & enter the passages between the four way cock or slide valve & the
check valve beforementioned. One port of each pair is placed so that when the
main valve is at the centre of its travel it will be just covered by it. The other
port of each pair is placed near the end of the main valve casing & is provided
with an adjustable stop screw which will open or close this port as required. The
result of this arrangement is that when the main piston arrives at the end of its
stroke & moves the four way cock or slide valve so as to place the passages before-
mentioned in communication with the water pressure & the exhaust the main valve
moves along until it arrives at the centre of its travel when it closes the main ports
leading into the cylinder & also one of each of the two pair of ports before-
mentioned. The only exit now remaining open for the escape of the water at the
end of the main valve which is exhausting is through the port having the stop
screw beforementioned & the speed at which the main valve moves during the
remainder of its travel is determined by the flow of water through this port. This
is regulated by the stop screw beforementioned & the main valve made to travel
slowly or quickly as required. The pistons which compose the main valve are
rounded at the ends which pass over the ports in the casing communicating with
the inlet & outlet passages so as to effect a more gradual opening when passing the
ports. This system of automatically controlling the main valve by means of two
pairs of ports being alternately covered by the ends of the main valve is also
applicable to a main valve consisting of a slide valve for controlling the inlet &
outlet of the water from the main piston this slide valve being actuated by a piston
valve the ends of which alternately cover two pairs of ports near the ends of the
main valve casing in the same inanner as already described.
Another modification consists in having the main valve which in this case would
be the same as that first described namely an equilibrium valve of the piston type
having three or more pistons for controlling the admission & escape of the water

page_text: from the main piston. This main valve as already described is moved backwards
& forwards by the water pressure which is admitted & exhausted at either end of
the main valve through passages communicating with a four way cock or slide valve
having its motion derived from the main piston & which alternately places these
passages in communication with the water pressure & exhaust.
The water pressure is admitted to the four way cock or slide valve through a
passage leading to it from the main inlet port or passage in the main valve casing
this passage being covered by the central portion of the main valve when it arrives
at the centre of its travel. This cuts off the supply of water to the four way cock
or slide valve & consequently the speed of the main valve is checked at this part of
its travel until it has moved slowly over the covered passage beforementioned by
means of the water leaking past the central portion of main valve when the passage
is again uncovered & the water passing freely through the four way cock or slide
valve to the end of the main valve moves it along to the end of its stroke.
Dated this 22nd day of October 1892.
ALEXANDER MORRIS MELVIN.
COMPLETE SPECIFICATION.
Improvements in Hydraulic Engines for Blowing Organ Bellows
or other purposes.
: :
ALEXANDER MORRIS MELVIN, 28 Charles Street, St. Rollox, Glasgow, in the
County of Lanarkshire, 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 :-
1 X
In order that my invention may be fully understood will describe it more
particularly by reference to the accompanying drawings which represent the parts
of apparatus above referred to.
Figs. 1 & 2, Sheet 1, are a sectional elevation & plan of a hydraulic engine
shewing one modification of my improvements.
The main valve consists of 3 pistons A', A2, A3, connected together in one
casting, which open & close the ports formed in the main valve casing & alternately
place the main piston B in communication with the water pressure and exhaust.
The ends of these pistons A1, A2, A3, which pass over the ports communicating
between the main. piston and water pressure and exhaust are rounded or tapered SO
as to assist the motion of the main valve in allowing the water to enter into and
pass out from the main cylinder more gradually.
C&D are passages which enter the ends of the main valve casing through the
covers E and F. G, and H, are check valves which allow the water to pass freely,
into the main valve, but prevent its exit at this point. The passages C and D
communicate with 4 way cock I. K is a passage communicating between 4 way
cock I and exhaust. L is a passage communicating between 4 way cock I and
water pressure. C and D are ports communicating between main valve casing
and passages C and D and are placed so that the ends of the pistons A' and A³
cover both when main valve is at the centre of its travel. C and D² are 2 ports
communicating between main valve casing & passages C and D. M and N are
2 screw valves for opening and closing the ports C², and D².
The 4 way cock I has 2 passages on opposite sides of the key, so that when the
cock I is moved round either way, the passages C and D are alternately placed in
communication with the water pressure and exhaust. The motion for working the
4 way cock I is derived from a lever O fixed on the outer end of 4 way cock I
which lever is caused to move by a rod P having 2 tappetts Q and R and
connected to main piston B of engine in the ordinary way.
Figs. 3 and 4 Sheet 2 shew a sectional elevation and plan of a hydraulic engine
having a slide valve A' which is actuated by a piston valve having
pistons A¹

page_text: and A connected by à bar with a projection fitting into slide valve A' which is
moved backwards & forwards over the ports formed in main cylinder and
alternately place the main piston B in communication with water pressure and
exhaust. The 2 pistons A' and A³ of the piston valve are moved backwards &
forwards by means of 4 way cock I which has passages communicating with either
end of main valve casing, these passages having a pair of ports at either end
arranged exactly as shewn in Figs. 1 and 2 Sheet 1 for the purpose of preventing
sudden admission of water through the ports into main cylinder..
In the foregoing arrangements the action of the main valve will be as follows:-
When the water is admitted to the main piston B with the various parts in position
shewn on drawing Figs. 3 and 4 it will move in the direction indicated by the
arrows, carrying with it the tappett rod P until the tappett R strikes the lever O
which moves round the way cock I and places the passage C in communication
with the water pressure and the passage D in communication with exhaust.
The main valve A' A' A' then moves in the direction shewn by arrow until at
nearly the centre of its travel the piston A³ covers the port D¹ when the water
being confined by check valve H the travel of main valve is checked and the
speed at which it now travels-is controlled by means of the quantity of water
allowed to pass through passage D' this being adjusted by opening or closing
passage D with the screw-valve N. When the main valve A' has moved so as to
admit the water to the reverse side of main piston B and to open the passage to the
exhaust the motion of the main piston B will be reversed and the ports and C
of main valve will act on its reverse stroke in the same manner as already
described.
Another modification of my improved valve is shewn on Figs. 5 and 6 Sheet 3
which represents a sectional elevation and plan of a main valve.
The water pressure for actuating said valve is admitted through port L to 4 way
cock I thence alternately by passages C and D to valve pistons.
When cock I is turned round so as to place passage D in communication with
the water pressure and passage C in communication with the exhaust the main
valve will travel until piston A partially closes port L. The speed of main valve
is thereby checked. The central port is made if necessary a little longer than the
piston A so that it may not be quite covered and bring the valve to a stand.
soon as piston A' has moved over port L the water passes freely through passage D
and moves main valve to the end of its travel.
As
Another modification is shewn on Figs. 7 and 8 Sheet 3 in which an ordinary
slide valve is used having a projection A which travels over a port L leading to
4 way cock so as to partially cut off the supply of water to pistons A' and A³ in a
similar manner and for the same purpose as already described.
Another method of controlling the main valve is shewn on Figs. 9 and 10 Sheet 4,
which are a sectional elevation and plan of a main valve only, similar to that shewn
on Figs. 5 and 6 Sheet 3 with the exception that instead of employing a central
port to be covered by the main piston I control the valve by means of suitably
shaped plugs S and T fixed either on main valve or as shewn on Figs. 9 and 10
fixed on covers of main valve casing.
The interior of the 2 pistons of main valve A' and A' at either end have
narrow strips U and V which are turned concentric with the exterior of pistons A¹
and A and are the same dia. as that of plugs S and T. C' and D' are passages
through the plugs S and T and, lead from the points of plugs to their base.
M. and N. are screw valves for opening or closing the passages C and D'. In this
method of controlling the main valve when the strips U. and V travel on to the
parts of plugs S and T which are the same diameter as strips U. and V. the water
is confined in the recess of pistons A' and A' and the only exit for the water being
through the passages C¹ and D¹ the speed at which the main valve travels at this
part of its stroke is controlled by the quantity of water allowed to pass through
passages C and D this being adjusted by opening or closing the passages C¹
and D with the screw valves M. and N. The same method of controlling the

page_text: main valve is applicable where instead of the central piston A² of main valve, an
ordinary slide valve A2 as shewn on Figs. 11 and 12 Sheet 4 is substituted.
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 :-
First. The means whereby the speed of the main valve A', A', A³ at or near the
centre of its travel is checked by means of water cushions and the water thus
confined allowed to escape past an adjustable screw valve, the speed of main valve
being thereby controlled to admit the water gradually to main piston. All as
substantially described.
Second. Admitting the water for working main valve. A A A³ through a
port L over which the said valve works, partially shutting off the water at the
centre of its stroke and thereby checking its speed all as substantially described.
Dated this Seventeenth day of June 1893.
ALEXANDER MORRIS MELVIN.