IMPROVED VALVE FOR USE IN AIR AND OTHER PUMPS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by the said David Thomas at the Office
of the Commissioners of Patents on the 23rd January 1880.
DAVID THOMAS, of Cardiff, in the County of Glamorgan, Engineer.
IMPROVED VALVE FOR USE IN AIR AND OTHER PUMPS."
'
" AN
This Invention relates to a construction of valve for use in air circulating and
other pumps, as bucket, foot, or delivery valves, and more especially for use in
connection with marine engines.
The ordinary india rubber valves hitherto used are very apt to stick on the seats
when hot, and are not so durable as desirable.
I construct my valve of metal as follows:-
It consists preferably of a metal disc formed true on its lower face where it rests
on a seating over the port, and preferably slightly bevelled on its upper face, except
at that part which strikes against the guard when the valve is rising.
I usually construct it of brass or other metal not liable to corrosion.
The guard is preferably circular, formed truly on its under surface, perforated as
usual, and forming part of a bush turned accurately on which the valve rises and
falls, and the interior of which bush is screwed onto a spindle fitted in the centre of
the port by wings or otherwise, or, in the case of a pump bucket, the bush and
guard is screwed onto the pump rod, and can be secured by set screws or
otherwise.
The upper part of the bush above the guard plate is preferably shaped like a nut,
so as to be easily unscrewed with a spanner, and these also act as a nut to hold the
spindle or rod in place, which is formed conically or of lesser screwed diameter for
the purpose at its lower end.
I turn a groove or grooves in the under side of the guard plate to insert a ring
of packing, such as rubber or flax gasking, to ease the shock to the valve striking

page_text: it, and likewise insert similar packings in the outer and inner edges of the valve
seat for the same purpose.
The action of the valve is similar to those already in use, the valve rising and
falling by the pressure or vacuum produced by the movement of the piston or
bucket of the pump.
When the seating or bucket area is large, I prefer fitting several valves instead
of one arranged as usual in such cases.
In the case of foot valves used with the air pumps of marine engines, I prefer to
construct them of zinc, so as to destroy the galvanic action before the condensed
steam is pumped into the boiler, thus doing away with the application of so large a
quantity of zinc plate being placed in the boiler.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said David Thomas in the Great Seal Patent Office on the 22nd July
1880.
DAVID THOMAS, of Cardiff, in the County of Glamorgan, Engineer. " AN
IMPROVED VALVE FOR USE IN AIR AND OTHER PUMPS."
This Invention relates to a construction of valves for use in air circulating and
other pumps, as bucket, foot, or delivery valves, and more especially for use in
connection with marine engines. The ordinary india-rubber valves hitherto used
are very apt to stick on the seats when hot, and are not as durable as might be
desired.
An illustration of my valve is shown in the accompanying Drawings, in which
Fig. 1 is a sectional elevation of air-pump of marine engine with the head and foot,
and also the pump bucket fitted with my improved valves; Fig. 2, plan of head
valve, showing half valve and half seat; Fig. 3, plan of pump bucket, showing half
valve and half seat; Fig. 4, sectional elevation, and Fig. 5, plan of foot valves
generally applied when the air-pump is of large size.
In these A is the sides of the air-pump; B, the valve; C, the valve guard; D, the
valve seating; E, bush; G, spindle or collar; H, pump rod.
The valve B consists of a plate or disc rising on a bush E. against a guard C, and
falling again onto its seat D. The under face which rests on the seating is formed
true, the upper side is slightly bevelled, except at that part which strikes against
the guard when the valve is rising. I usually construct it of brass or other metal
not liable to corrosion.
The guard c is preferably circular formed, with the under surface true and parallel to
the face of the valve B, perforated as usual, and forming part of an accurately turned
bush E on which the valve B rises and falls. The interior of the bush E is screwed
on to a spindle or collar G, according to the situation of the valve. If for instance
it is applied as a foot valve a spindle is used, if as a head valve a collar through
which the pump rod H works. The spindle or collar is secured in the centre of
the port by wings or otherwise, or in the case of a pump-bucket the bush E and
guard c are screwed on to the pump rod H, and can be secured by set-screws or
otherwise.
The upper part of the bush E above the guard plate G is preferably shaped like
a nut so as to be easily unscrewed with a spanner, and in the case of the pump-
bucket this acts as a nut to hold the spindle or rod in place, said spindle or rod
being formed conically or with a shoulder for the purpose at its lower end.
If required, I turn a groove or grooves in the underside of the guard plate C, to
insert a ring of packing c, such as rubber or flax gasking, to ease the shock to the
valve striking it, and I may insert similar packings c in the outer and inner edges
of the valve seat for the same purpose, as seen in the pump-bucket, Fig. 1.
The action of the valve B is similar to those already in use. The valve B rises
and falls on the bush E by the pressure or vacuum produced by the movement of
the piston or bucket of the pump.
When the seating or bucket area is large, I prefer fitting several valves instead
of one arranged as usual in such case, as seen in Figs. 4 and 5 in the Drawings.
In the case of foot valves used with the air pumps of marine engines, I prefer to
construct them of zinc, so as to destroy the galvanic action before the condensed
steam is pumped into the boiler, thus doing away with the application of so large a
quantity of zinc plate being placed in the boiler.
Having now described my Invention, and the best modo known to me of carrying
it into effect, I wish it to be understood that what I believe to be new and desire
to protect under the herein before in part recited Letters Patent is,―
First. The manufacture of valves for use in air and other pumps of a solid plate

page_text: or disc rising and falling on a bush or spindle in a direction at right angles to the
valve seat, substantially as described.
Second. The manufacture of foot valves for the air pumps of steam engines of
zine, substantially as described, for the purpose of destroying the galvanic action
before the condensed steam is pumped into the boiler.
Third. The general arrangement and construction of valves for air and other
pumps, substantially as herein described and shown.
In witness whereof, I, the said David Thomas, have hereunto set my hand
and seal, this Sixteenth day of June, in the year of our Lord One thousand
eight hundred and eighty.
DAVID THOMAS. (L.S.)