IMPROVEMENTS IN PUMPING MACHINERY ACTUATED BY STEAM OR OTHER FLUID
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by John Isaac Thornycroft at the
Office of the Commissioners of Patents, with his Petition, on the
• 21st September 1875.
. I, JOHN ISAAC THORNYCROFT, of the Firm of John I. Thornycroft
and Co., Steam Yacht and Launch Builders, of Church Wharf, Chiswick,
in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN PUMPING MACHINERY ACTUATED BY STEAM
OR OTHER FLUID," to be as follows:-
This Invention has for its object improvements in pumping machinery
actuated by steam or other fluid.
•
Ordinary steam pumps with rotary motion are in many cases open to
the objection that considerable speed is necessary to ensure their¨¨
continued working. Moreover the fly wheels alternately have to take.
up and give out again a considerable amount of energy, causing great
wear and tear and necessitating strong proportions, and lastly if the
supply of fluid to be pumped fails or if an excess of motive fluid be
admitted to the valve chests the engines are liable to "run away."

page_text: Pumps worked with steam moved valves besides being liable to the
last mentioned objection are furthermore objectionable in having
internal parts liable to stick fast when impure steam, or in other words
steam containing dirty water, happens to pass through them.
Now my Invention is designed to produce a pumping engine which
whilst fulfilling the objects aimed at in pumps of the classes above
referred to shall be free from the objections I have indicated.
When herein-after-I-use the words "steam pump" in describing my
Invention it is to be understood that I mean the complete-machine, and
include also pumps actuated by other fluid.
In my improved steam pump there is only one steam valve and one
steam piston. The steam valve is moved in the first place through
suitable connections by the steam piston so far as to close the valve and
ultimately stop the motion of the piston, and the further motion of the
valve required to admit steam at the opposite side of the piston so as to
make the return stroke is obtained from a weight set in motion or lifted
during the motion of the steam piston.
The weight which acts as a kind of governor is so arranged and
applied that whatever may be the position of the piston on steam being
admitted the weight will by the movement of the piston be brought
into position in due time to cause the required movement of the valve
for ensuring the continued working of the pump, or in the event of any
accidental stoppage the pump may be instantly started by merely
moving the weight by hand.
One arrangement is as follows:-A transverse shaft is arranged over
the piston rod between the steam cylinder and the pump cylinder; on
this shaft is fixed an arm (herein-after called the weight arm), having its
free end upward-;-this arm carries a collar or piece for moving the valve
rod; above this collar or piece is the weight, a spring or other buffer
arrangement being interposed between them; centred freely on the shaft
is-a-lever, whose lower arm is moved to and fro radially by the recipro..
cating piston rod; its upper-arm-constitutes or carries a cam which at the
proper times comes in contact with the collar or piece on the weight arm,
which arm by the movement of the cam is tilted, thus bringing the
weight into operation in the required direction; the valve rod has a
link carrying two-projections, one of these enters a slot in the lower arm
1.

page_text: of the lever, the other enters a cam piece working freely on the transverse
shaft, and operated at the proper times by the collar or projecting piece
of the weight arm when that arm is caused to fall by the weight.
Whilst a port is open and the piston is being moved by the entering
steam, the lever cam will be gradually raising the weight arm and weight;
upon the closing of the port by which steam has been entering the
weight arm will have just passed the vertical position; the weight will
cause the arm to fall, bringing its collar or projection into contact with
and causing it to move the cam connected to the valve rod, thus
throwing over the valve and admitting steam to effect the return stroke.
The position of the weight on its arm may be adjusted according to the
speed at which it is desired to work.
It will be obvious that pumping engines in which the movement of
the valves is partially effected by means of a weight moved into position
for that purpose by the actuating piston may be constructed in various
forms without departing from the principle of my Invention, also that
such engines may be arranged in pairs or otherwise as circumstances
may necessitate.
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