Improvements in and connected with the Valve Gear of Prime Movers.
Year: 1898

page_text: Date of Application, 4th May, 1898
Complete Specification Left, 31st Jan., 1899-Accepted, 4th Mar., 1899
PROVISIONAL SPECIFICATION.
Improvements in and connected with the Valve Gear of Prime
Movers.
I, JAMES APPLETON, of 23, Carlton Street, Eccles New Road, Salford, Manchester,
in the County of Lancaster, Engineer, do hereby declare the nature of this inven-
tion to be as follows;-
My said invention relates to improvements in and connected with valve gear
and refers more particularly to improvements upon a former invention for which
I have obtained Her Majesty's Royal Letters Patent No. 13177 of 1897.
In the specification of my former invention I described a method of positively
actuating the piston valves of double acting pumps. In such method the piston
of the steam cylinder was arranged to actuate tappets at the end of each forward
and backward stroke. The tappets were secured to spindles working within short
cylinders secured to the cylinder covers. Two chambers were formed within the
cylinders communication between which was controlled by valves on the spindles.
Springs were employed to return the valves on their seats when the tappets were
released by the piston.
It is found in practice that the constant action of the live steam has a detri-
mental effect upon the spring.
Moreover in the arrangement shown, the admission of steam to the back of the
piston valve was too prolonged as steam was admitted immediately the tappet was
operated by the piston in the steam cylinder and continued until released by the
piston. This presented difficulties in the rapid exhausting of the steam as soon
as the piston valve was traversed in the required direction.
The object of my invention is to overcome these defects which I do by dispensing
with the springs and utilizing the pressure of steam alone to return the tappet and
close the valve regulating the admission of steam to the valve chest.
Further I also arrange to regulate the admission of steam to the valve chest.for
operating the piston valve so that only sufficient steam to operate the valve is
admitted to the valve chamber which steam is readily exhausted.
In carrying my invention into effect I provide the steam cylinder covers with
short cylinders within which work pistons of suitable length. To the pistons are
attached tappets projecting within the interior of the steam cylinder. Steam is
admitted by means of pipes from the steam chest to the short cylinders by way
of ports in the front and rear of the short cylinders. Normally when the tappets
project to their fullest extent within the steam cylinder the pistons are at the
front end of the cylinders. In this position they cover the front steam ports and
close the pipes leading to the piston valve.
The rear ports being open the pressure of steam behind the pistons maintains
them in this position. On the tappets being operated by the piston in the steam
cylinder the pistons are thrust towards the rear of the short cylinders and the
front steam port being thus uncovered admits steam along the pipes to the piston
valve which is thus operated.

page_text: When the front steam port is thus opened the pressure of steam in front and
behind the pistons is in equilibrium but immediately the piston valve has been
traversed and the exhaust port in the valve chest is opened the equilibrium is
destroyed and the pressure of steam behind the piston in the short cylinder returns
it to its normal position thus cutting off steam from the front port and closing
the steam pipe communicating with the piston valve.
The front ports in the short cylinders may be so arranged that the tappets
must be traversed some little distance before steam is admitted to the pipe com-
municating with the piston valve, unlike my former invention in which steam was
admitted to the piston valve during the whole time in which the tappets were
operated by the piston of the steam cylinder.
Thus, just sufficient steam only may be admitted to the piston valve as is neces-
sary to operate it which minimum amount of steam is readily exhausted.
The area of the front ports may also be regulated by a screw or similar means.
In my present invention the handles for manually operating the valve
spindle to effect the starting of the pump are dispensed with. In lieu of these
I provide the piston valve with a lever or cam operated by a handle so that the
piston valve can be worked backwards and forwards by means of the handle. This
is particularly useful in case the piston valve should work stiff after a long rest,
or in case the piston valve should stop on a dead centre.
The method of exhausting the steam used for operating the piston valve
remains the same as is my said former invention.
COMI DEIN DIEULTIVATION.
Improvements in and connected with the Valve Gear of Prime
Movers.
I, JAMES APPLETON, of 23, Carlton Street, Eccles New Road, Salford, Manchester,
in the County of Lancaster, Engineer, do hereby declare the nature of this inven-
tion. and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement and accompanying drawings:-
My said invention relates to improvements in and connected with valve gear
and refers more particularly to improvements upon a former invention for which
I have obtained Her Majesty's Royal Letters Patent No. 13177 of 1897.
In the specification of my former invention I described a method of positively
actuating the piston valves of double acting pumps. In such method the piston
of the steam cylinder was arranged to actuate tappets at the end of each forward
and backward stroke. The tappets were secured to spindles working within short
cylinders secured to the cylinder, covers. Two chambers were formed within the
cylinders communication between which was controlled by valves on the spindles.
Springs were employed to return the valves on their seats when the tappets were
released by the piston.
It is found in practice that the constant action of the live steam has a detri-
mental effect upon the springs.
Moreover in the arrangement shown the admission of steam to the back of the
piston valve was too prolonged as steam was admitted immediately the tappet was

page_text: operated by the piston in the steam cylinder and continued until released by, the
piston. This presented difficulties in the rapid exhausting of the steam as soon
as the piston valve was traversed in the required direction.
The object of my invention is to overcome these defects which I do by dispensing
with the springs and utilizing the pressure of steam alone to return the tappet and
close the valve regulating the admission of steam to the valve chest.
Further I also arrange to regulate the admission of steam to the valve chest for
operating the piston valve so that only sufficient steam to operate the valve is
admitted to the valve chamber which steam is readily exhausted.
The accompanying sheet of drawings more clearly illustrates my invention.
Fig. 1 of the drawings shows in sectional elevation the steam cylinder of a pump
fitted with my invention.
Fig. 2 is a view of the same at right angles also in section.
Fig. 3 is a detail view.
In carrying my invention into effect I provide the steam cylinder covers A A
with short cylinders a a within which work pistons 6 of suitable length.
In Fig. 1 one of the cylinders a is shown in section and the other in outside view.
It will be understood however that a description of one applies equally to
the other.
The cylinders a a are formed with valve seatings a¹ for the pistons b. In
addition to the pistons 6 there are provided tappets c c projecting within the
interior of the steam cylinder B. The tappets c may be formed in one with the
pistons 6 if desired but are shown in the drawings disconnected so that different
metals may be employed.
For instance the cylinder a and piston 6 may be of brass or other anti-friction
metal and the tappets c may be made of steel.
Steam is admitted by means of pipes d from the steam chest e to the short
cylinders by way of ports f f¹ in the front and rear of the short cylinders, as shown
more clearly in the sectional plan view Fig. 3. Normally when the tappets pro-
ject to their fullest extent within the steam cylinder B the pistons 6 are at the
front end of the cylinders as shown in the drawings. In this position the piston b
covers the front steam port f¹ and the pipes g leading to the piston valve are
closed.
The rear ports f being open the pressure of steam behind the pistons 6 maintains
them in this position. On one of tappets being operated by the piston C in the
steam cylinder B the piston 6 is thrust towards the rear of the short cylinder and
the front steam port f being thus uncovered admits steam along the pipe g to the
back of the piston valve which is thus operated.
When the front steam port f¹ is thus opened the pressure of steam in front and
behind the piston 6 is in equilibrium but immediately the piston valve D has been
traversed and the exhaust port in the valve chest is opened the equilibrium is
destroyed and the pressure of steam behind the piston 6 in the short cylinder a
returns it to its normal position thus cutting off steam from the front port f¹
and closing the steam pipe g communicating with the piston valve D.
The front ports f¹ in the short cylinders a are arranged in the rear of the pipes g
so that the tappets must be traversed some little distance before steam is admitted
to the pipe g communicating with the piston valve D unlike my former invention
in which steam was admitted to the piston valve during the whole time in which
the tappets were operated by the piston of the steam cylinder.
Thus just sufficient steam only may be admitted to the piston valve as is
necessary to operate it which minimum amount of steam is readily exhausted.
The area of the front ports f¹ may also be regulated by a screw or similar means.
In my present invention the handles for manually operating the valve spindle
to effect the starting of the pump are dispensed with. In lieu of these I provide
the piston valve with a lever or cam h operated by a handle i so that the piston
valve D can be worked backwards and forwards by means of the handle i. This
is particularly useful in case the piston valve should work stiff after a long rest,

page_text: or in case the piston valve should stop on a dead centre. I do not however
claim as novel this means of operating the piston valve manually.
The method of exhausting the steam used for operating the piston valve remains
the same as in my said former invention.
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:-
The improved means of operating the piston valves used in steam pumps and
similar motors consisting of the cylinders a in communication with the steam
supply, secured to the steam cylinder covers, and provided with steam ports f f
and pistons 6 the pistons being operated by means of tappets at the required times
to admit steam from the cylinder a to the back of the piston valve and closed on
the release of the tappets by the pressure of steam behind substantially as described
and illustrated.
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1000