Improvements in Compression Pumps.
Year: 1894

page_text: Date of Application, 22nd June, 1894-Accepted, 28th July, 1894
COMPLETE SPECIFICATION.
Improvements in Compression Pumps.
I, PETER STAHL, Engineer of 15 Mitterer Strasse, Munich in the Kingdom of
Bavaria, Germany, do hereby declare the nature of my invention and in what
manner the same is performed to be particularly described and ascertained in and
by the following statement :-
The present invention relates to the construction of the cylinders of compression
pumps for compressing gases, and consists in means for reducing the noxious space
before the piston to a minimum, and for augmenting the tightness of the piston in
the cylinder.
:
The invention consists in giving the ends of the compression cylinder or
cylinders a concave form, and the piston a convex form, and in arranging the
valves in the said concave cylinder cover radial to the curve of the concave
interior surface, and in providing a piston having a circular hollow passage round
the same behind the packing rings, into which the fluid at the front of the
piston has free passage, so that the pressure of the said fluid passing from one
cylinder to the other alternatively will be utilised to press the packing ring of the
said piston onto the sides of the cylinder and at the same time lubricate the said
piston.
And in order to make my present invention more easily intelligible reference is
had to the accompanying drawing in which similar letters denote similar parts
throughout the several views:-
Fig. 1 being a side elevation of one cylinder of a compression pump constructed
according to my invention as seen when the two cylinders are separated along the
line in Fig. 2,
Fig. 2 is a plan of the cylinders showing one of the same in horizontal
section,
Fig. 3 is a vertical section on the line y y in Fig. 2 and
Fig. 4 is a horizontal section through the suction and pressure valves arranged in
the concave cover of the cylinder.
Upon the bedplate A are arranged the two cylinders B and B' having pistons D
with piston rods F, F' and a cover G common to both cylinders, said cover being
concave at the interior of the cylinders and having a channel H connecting the
space in front of the two pistons of the cylinders. The piston D, (Fig. 4) is
provided with a circular groove or channel behind the packing ring, into
which a small channel f' leads from the forward side of the piston D. To the
back cover of the cylinders are attached the suction and pressure valves a and b,
mounted in the throat pieces I respectively. The said throat-pieces are
provided with flanges and suitable covers and are arranged radially to the inner
concave surface of the said cover. Within the suction valve a is a bush K,
having centrally arranged therein a guide sleeve a' for the valve spindle carrying
the valve, said spindle being held in a position to keep the valve on its seat by a
spring c. In the throat piece I' is a bush K having two sleeves to guide the
valve spindle band a spring e' arranged between the two sleeves to hold the valve
on its seat.
The operation of the apparatus when employed for the liquefaction of carbonic
acid gas takes place in the following manner :-
The gas to be compressed is led from the gasometer along the pipes to the
suction valve of the compression cylinder B and is compressed in this cylinder
to 10 to 15 atmospheres and passes then through the pressure valve 6 and along
the pipe into a purifier S, where it may be freed from any impurities by

page_text: some suitable reacting fluid. The gas thus purified is then drawn into the
second cylinder 13' along the pipe and driven thence into the coil of a con-
denser in which it is liquefied at about 60 atmospheres pressure whereupon it
may be drawn off in bottles or flasks or employed in any other manner.
The opposite sides of the pistons to those on which the valves are situated are
filled with glycerine or any other suitable oil, which on the working of the pump is
driven from one cylinder to the other alternatively, said fluid being able to enter
through the channel the hollow circular space in the piston behind the packing
ring, thus the packing ring will be continually pressed against the cylinder walls
by the fluid entering the piston behind it which fluid will simultaneously serve to
lubricate the said piston.
One or more channels may be provided in the piston.
Having now particularly described and ascertained the nature of my inven
tion and in what manner the same is performed declare that what I
claim is :-
1. In a double cylinder compression pump, the combination of a piston having
convex surfaces, and cylinder covers having a concave form and suction and
pressure valves arranged as specified and a channel H connecting the front ends
of the said cylinders substantially as described.
2. The combination of a piston having convex surfaces, and cylinder covers
having concave surfaces corresponding to the said convex surfaces of the piston, a
channel connecting the front ends of the two cylinders, suction and pressure
valves arranged radially to the inner concave form of the back cover and attached to
the said back cover, and suitable fluid in front of the said pistons to flow backward
and forward between the cylinders substantially as described.
3. The combination of a piston having convex surfaces, and cylinder covers
having a concave form, suction and pressure valves arranged radially in the back
cover of said cylinders, a channel H connecting the front ends of said cylinders,
suitable fluid in said front cylinder ends as specified, a circular groove around said
piston at the rear of the packing ring and access orifices for the said fluid
into the said piston groove in the manner and for the purpose substantially as
described.
Dated this 22nd day of June 1894.
W. P. THOMPSON & BOULT,
Agents for the Applicant.