Barmag Ag

Barmag Barmer Maschinenfabrik Ag

Otwin Eich

Franz-Peter Salz

Heinz Schippers

Siegfried Hertell

Karl-Heinz Post

Hydraulic system

A hydraulic throttle valve is disclosed which includes a choke piston slideably mounted in a bore for movement between an open position and a closed position. A differential piston is coaxially mounted with respect to the choke piston, and a control valve is mounted for slideable movement in a second bore which is laterally spaced from and parallel to the first bore. The control valve is operated by an electromagnet to selectively direct a control fluid to either side of the differential piston, and thereby open or close the choke piston. A feedback spring arm interconnects the choke piston and the control valve, with the spring arm resisting the opening of the choke valve and with the resisting force being a function of the force applied to the control valve by the electromagnet. A balance of forces acting on the choke piston is thereby achieved, with the choke piston being opened to an extend functionally related to the magnitude of the input current to the electromagnet. A shuttle valve is also provided which is operatively connected to each of the hydraulic inlet channel and the hydraulic outlet channel of the throttle valve, with the output of the shuttle valve being operatively connected to the control valve. The shuttle valve acts to connect that one of the inlet and outlet channels having the higher pressure, to the control valve.

Throttle valve

A positive displacement reciprocating pump for conveying a liquid or gaseous fluid is disclosed and which comprises a fluid enclosure having a movable piston means mounted therein which sealably divides the enclosure into a pumping chamber on one side and an actuating chamber on the other side. The piston means may comprise either a slideable piston or a flexible diaphragm. An inlet valve and a separate outlet valve are each connected to the pumping chamber, and a control system is provided for intermittently supplying a pressurized working fluid to the actuating chamber so as to intermittently move the piston means in the discharge direction, with the piston means being moved in the opposite or suction direction by either the pressure of the fluid being conveyed, or a suitable spring. The control system for advancing the piston means in the discharge direction includes a source of pressurized working fluid, a working fluid line extending between the source and the actuating member, and a valve operatively connected to the working fluid line for intermittently opening the line to a discharge tank or the like to release the pressure therein.

Control apparatus for a positive displacement reciprocating pump

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Remscheid, Germany

Otwin Eich