Improvements in and Connected with Pumps for Pumping or Moving Air and Gases.
Year: 1887

page_text: Date of Application, 14th Mar., 1887.
Specification Accepted, 15th Apr., 1887.
COMPLETE SPECIFICATION.
Improvements in and Connected with Pumps for Pumping or
Moving Air and Gases.
1 ERNST HÜBNER, Manufacturer, of Halle "/S., in the Kingdom of Prussia and
German Empire do hereby declare the nature of my said invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement:-
For the purpose of avoiding special slides, valves, or channels and the like for
equalizing the pressures in the clearance and other waste spaces of air and gas pumps,
the controlling slide according to this Invention consists of a slide valve with a
negative outer lap, or covering and the space in the valve box is used for the passing
of the air, or gases at the dead point positions of the piston. In order to render this
possible the delivery valve (which is fitted with a spring as ordinarily used in the
delivery pipes of such pumps) is applied to the cover of the valve box. The latter is
kept as small as possible and made to suit the outside shape of the slide valve. The
delivery valve therefore regulates the escape of air, or gases out of the cylinder into
the atmospheric air in vacuum pumps, or into the delivery pipes of compressing
pumps, but remains shut during the equalization of pressure, so that the slide box can
serve as a receptacle for the passage of air, or gases and thus serves as a means of
equalizing the pressure. The controlling and equalization of pressure are therefore
both effected by the cooperation of the slide valve having outside negative lap and
made to suit the valve box, and the delivery valve, the said valve being provided with
a spring and applied to the cover of the slide box. In operation air, or gas enters
the cylinder through the slide valve only and it escap
capes into the air, or into the delivery
pipes solely through the delivery valve and finally the equalization of the pressures is
effected by the valve box, the entrance of air, or gas being shut off by the slide valve
and the escape is closed by the delivery valve.
The pump is represented in longitudinal section Figure 1 and in cross section
Figure 2 in the accompanying Drawings. These Figures 1 and 2 show that the slide
valve A is provided with negative outside lap, that is, it is of such dimensions that
when in its middle position, that is to say when the piston B is in its dead point
positions, the forcing space is connected with the suction space of the cylinder for a
short time by means of the ports a a' and the space d of the slide box Ď. The slide
valve A as above described is fitted for this purpose with a negative lap, or outside

page_text: covering, that is to say, it does not completely cover the two ports a a¹ when in its
middle position as may be seen in Figure 1.
The slide valve works in the space d of the slide box D. The dimensions of the
latter are made as small as possible. The delivery valve which is provided with a
spring and applied direct to the cover of the slide box opens outwards. If the
pump is used for compressing air, or gas, the delivery pipe is attached to the cover f
of the slide box as is indicated by dotted lines in Figure 1.
9
In the indicated position the plunger B has just completed its stroke, the slide
valve A has shut off the suction port e from a and has established a connection of the
forcing space before and behind the plunger by means of the port a space and
port a. The compressed air, or gas rushes from the left side to the right side of the
piston and in this way equalization of pressure is effected. During the equalization
the valve box space d is shut off by means of the delivery valve from the outside, or
from the delivery pipe h. When the equalization of pressure is completed, the slide A
while moving to the left shuts off the channel a first and opens it towards whereas
the plunger while moving to the right draws in fresh air, or gas behind it, compresses
the air, or gas in front of it and forces it through the port a, space d and valve b.
This operation is continued until the slide A which has in the meantime altered the
direction of its movement shuts off the suction port al from e¹ and opens itto the valve.
box space d when the plunger has reached the dead point position on the right. At
the same moment and when the delivery valve is shut, the compressed air, or gas
rushes from the right side to the left side of the cylinder.
h
As may be seen from the operations just described, the slide A regulates only the
entrance of air, or gas into the cylinder, the delivery valve opens as soon as one of
the two ports a a¹ is opened to the space d and closes before the said port is shui off
again by the slide A. This valve therefore regulates the escape of air, or gas into
the open air, or into the delivery pipe and consequently forms a material part of the
regulating and compensating contrivance. It is placed direct onto the cover of the
slide box to keep the space d as small as possible and to permit the equalizing of
the pressure to take place fully. During the equalization the slide A shuts off the
entrance of air or gas into the cylinder, the valve prevents the escape of air, or gas
into the open air, or into the delivery pipe, so that the air, or gas can rush out of the
forcing space of the cylinder through the space d of the slide box into the suction
space of the cylinder.
Having now particularly described the nature of my said Invention and in what
manner the same is to be performed, 1 declare that what I claim is :-
First. Equalizing the pressures on opposite sides of the piston of an air, or gas
pump by the cooperation of a slide valve provided with negative outside lap and of a
delivery valve placed and fitted in such a manner that during the equalization of the
pressures such delivery valve is shut and the equalization of the pressures is effected
by the passage of the air, or gas through the hollow space of the slide box, while ou
the other hand the said valve regulates the escape of the air, or gases into the open
air, or into the delivery pipe during the compressing, or forming of a vacuum
substantially as set forth.
Second. The slide valve A valve box D. delivery valve ports a a and c arranged
constructed and operating substantially as set forili with reference to the Drawings.
Data: Cl
1007