Hydraulically controllable mechanical seal

Abstract

A controllable mechanical seal for sealing a shaft rotatable relative to a housing of a device which manipulates a fluid, the seal including: (i) a first face element having a first face surface, wherein the first face element is adapted to rotate with the shaft; (ii) a second face element having a second face surface, wherein the second face element is adapted to be supported within the housing; wherein the first face surface and the second face surface define a gap between the surfaces, physical dimensions of the gap contributing to defining a leakage rate of the fluid through the gap; wherein at least one of the first face element or the second face element includes at least one cavity wholly contained within the face element, the at least one cavity adapted to contain a hydraulic fluid; and wherein the at least one cavity is in fluid communication with at least one hydraulic intensifier and at least one pressure control valve, the at least one hydraulic intensifier being in pressure communication with a source of pressure; (iii) a sensor adapted to generate a signal indicative of the leakage rate; and (iv) a controller responsive to the signal for generating an output; wherein a state of the at least one pressure control valve is adapted to change in response to the controller output in order to increase or decrease the pressure of the hydraulic fluid in the at least one cavity, thereby deforming one of the first face surface or the second face surface to adjust the leakage rate.