Importance

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Abstract

Control valve for a hydraulic elevator provided with a speed regulating plug which moves in response to the flow of the hydraulic fluid and whose position determines the flow of hydraulic fluid into the actuating cylinder of the elevator. At each end of the speed regulating plug, there is connected a system of hydraulic channels in which the hydraulic fluid flows, and which communicates with the main hydraulic circuit. An additional channel is connected to the hydraulic channel system, the additional channel being provided with a flow resistance component comprising a capillary throttle and a pressure compensated reservoir, such that the flow of hydraulic fluid through the additional channel is varied in inverse relation to the viscosity of the fluid. By this means, the closing speed of the speed regulating plug, and thus the deceleration rate of the elevator, is maintained constant throughout the operating temperature range of the hydraulic fluid.

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First Claim