Hydraulically powered diaphragm pump with pretensioned diaphragm
AssigneeLEWA Herbert Ott GmbH & Co.
InventorsNils Kohlhase, Waldemar Horn, Ruediger Schnorr
Life of this patent
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Abstract
A hydraulically driven diaphragm pump with a diaphragm clamped at its edge between a pump body and a pump cover separating a delivery chamber from a hydraulic chamber and pretensioned in the direction of its intake stroke by spring force. A hydraulic diaphragm drive in the form of an oscillating displacement piston is displaceable in the pump body between a reservoir chamber for the hydraulic fluid and the hydraulic chamber. The diaphragm is so strongly pretensioned by spring force that it exerts a substantial compressive force on the hydraulic fluid in the hydraulic chamber. Therefore a substantial hydrostatic pressure is built up in the hydraulic chamber relative to the delivery chamber.
Claims9
Hydraulically driven diaphragm pump comprising:
- a pump body,
- a pump cover,
- an edge of a diaphragm clamped between the pump body and the pump cover, the diaphragm separating a delivery chamber from a hydraulic chamber,
- a spring force pretensioning the diaphragm in a direction of an intake stroke, and
- a hydraulic diaphragm drive including an oscillating displacement piston, said oscillating displacement piston being displaceable in the pump body between a reservoir chamber for hydraulic fluid and the hydraulic chamber,
- the diaphragm being pretensioned by the spring force so that only the spring force controls a position of the diaphragm and the diaphragm follows an intake stroke of the piston even when a vacuum is present in the delivery chamber, and, when the pump is static, the diaphragm does not move in a direction of a compression stroke due to internal leakage even when the vacuum is present in the delivery chamber while the diaphragm remains in a rear dead center position, the diaphragm being only supported by a surface that is formed by part of the pump body and by a diaphragm coupling disk, the spring force being so dimensioned that a pressure in the hydraulic chamber is always at least 1 bar greater than a positive pressure in the delivery chamber.
Dependencies are inferred from the claim text.