Mechanical seal with automatic gap convergence control

摘要

A controllable mechanical seal for sealing a shaft rotatable relative to the housing of a fluid machine includes first and second face elements having first and second radial surfaces. The first element is adapted for rotation with the shaft. The second element is adapted to be stationary within the housing. One of the elements is movable axially relative to the shaft. The first and second surfaces are adapted to define a gap within which there is a thin lubricating fluid film. An actuator is provided for deforming at least one of the surfaces so that the gap converges in a direction from a high pressure side to a low pressure side of the seal. A sensor is provided for measuring a temperature indicative of incipient contact of said surfaces. A control system responsive to the sensor generates an external voltage which is applied to the actuator to control the convergence of the surfaces and thus maintain an optimum thickness of the lubricating film for a wide range of operating conditions.