Improvements in Pumps and Compressors for Air and other Gases.
Year: 1895

page_text: COMPLETE SPECIFICATION.
Improvements in Pumps and Compressors for Air and other Gases.
I, ERNST HÜBNER, of Halle on the Saale, in the Province of Saxony, German
Empire, Councillor of Commerce 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 :-
This invention refers to double-acting vacuum-pumps and compressors for air
and other gases, in which the piston co-operates with a slide-valve, as in an ordinary
steam-engine; my improvements in pumps or compressors of said kind relate to the
construction of the slide-valve as well as to the configuration of the valve seat, and
the purpose of my improvements is to do away with the injurious influence resulting
from the clearance of the cylinder proper and the inlet and outlet.
Said injurious influence consists in the lessening of the volume of the sucked gas
by the compressed gas remaining within the clearance, and I obviate said loss of
volume by letting said remaining compressed gas escape into the cylinder-chamber
at the other side of the piston.
For this purpose, I construct the slide-valve in such a manner, that in the middle
position of the same the sucking channel (c) of the cylinder and the delivery-
ports (ff) of the slide-valve are perfectly closed, whilst there is established a
communication between the inlet- and outlet-gas-port (de) of the cylinder. There
occurs thus during that time in which the slide-valve is in the position just described,
the escape of the remaining compressed gas into the cylinder-chamber at the other
side of the piston; if the parts are in the position shown in the drawing, the
remainder of the compressed gas within the cylinder-chamber k' flows through d, a
and e into the cylinder-chamber k².
The slide valve a is on its face provided with four ribs 6 forming five slide-valve
ports, and the valve-seat is furnished with three ribs d' c'e' forming each two
ports; there are thus two ports for either of the channels c, d and e, and the
opening or closing of either of said channels occurs thus at two ports simultaneously,
which allows of opening and closing said channels in very short time.
The positions of the ribs b and the face-portions of the inner wall of the slide-
valve a with regard to the ports of the channels C, and e is such a one, that there
is established a communication between the channels de as soon as the slide-valve
arrives in its middle position (compare the drawing).
When the slide-valve a is in either of its end-positions, there communicates either
the cylinder-channel d with the slide-valve channel f, or the cylinder-channel e with
the slide-valve channel f1, and the compressed air or gas is thus forced into the
valve-box i through one or the other of said channels ff. Each of the latter is
provided with a closing-organ that may be formed by valves such as g or h, or by
any other suitable contrivance. Owing to the arrangement of said closing-organs
directly upon the slide-valve, the clearance is but a small one, and the gas already
compressed re-acts upon the piston during the escape-period only, i.e. when the
degree of compression of the gas contained within the cylinder is equal to that
existing within the valve-box.
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 :-
1. In a vacuum-numn or compressor for air and other cases the combination

page_text: with the cylinder having channels such as d, e, c, of a slide-valve having ribs such
as b, the latter being arranged so as to cause closing of said channel c, as well as
communication between said channels d and e at each change of stroke, for the
purpose as described.
2. In a vacuum-pump or compressor for air and other gases, the combination
with the cylinder having channels, such as d, e, c, of a slide-valve having channels
such as ff, the latter being provided with closing-organs such as g or h, for the
purpose as described.
3. In a vacuum-pump or compressor for air and other gases, the combination
with the cylinder having channels such as d, e, c, with double or multiple ports at
the valve-seat, of a slide-valve having ribs such as b, and channels such as ff';
said ribs being arranged so as to cause closing of said channel c as well as com-
munication between said channels d and e at each change of stroke; said closing as
well as the opening of either of said channels e, d, c occurring at at least two parts
simultaneously, substantially as described.
Dated this 12th day of March 1895.
ERNST HÜBNER,
By Geo. H. Rayner,
37 Chancery Lane, London, W.C., Agent for the Applicant.