Adaptive control system for mechanical seal assembly

An adaptive control system for a mechanical seal assembly of the type including first and second seal faces, a housing for containing fluid adjacent the seal faces, one of the seal faces being movable toward and away from the other seal face to regulate a gap, and thus adjust a film thickness, between the respective seal faces, an actuator connected to regulate displacement of the movable seal face to adjust the film thickness, a first sensor positioned to provide a first signal which varies as a function of the temperature of one of the seal faces, a second sensor positioned to provide a second signal which varies as a function of the fluid temperature, said control system being coupled to both sensors and to the actuator, and a signal conditioner circuit in the control system connected to receive the first and second signals and provide a resultant signal which varies as a function of the temperature difference between the fluid and the seal face in which the first sensor is positioned, for regulating the actuator as a function of said temperature difference, the control system being operable, in response to identifying the presence of a limit cycle oscillation on the resultant signal, to identify a reference position of the movable seal face, and thereafter to displace the movable seal face away from the reference position and from the other seal face to establish a film thickness at which a limit cycle oscillation is not present.

The method of controlling a mechanical seal assembly having two faces, one face being displaceable with respect to the other face to adjust the gap and thus regulate the thickness of a film defined between the faces, comprising the steps of:

• initiating seal assembly operation with a given film thickness greater than an optimum film thickness;
• gradually decreasing the film thickness;
• examining a parameter of the seal assembly for an indication of a given phenomenon;
• and
• upon recognizing that the phenomenon has occurred, increasing the film thickness until the phenomenon is no longer present, thus providing seal assembly operation at an optimum film thickness.

The method of using a data processor with a memory array in controlling a mechanical seal assembly having two faces and fluid adjacent the faces, one face being displaceable with respect to the other face to adjust the gap and thus regulate the film thickness of the fluid between the faces, comprising the steps of:

• initiating seal assembly operation with a given film thickness which produces excessive leakage;
• sensing the temperature of one face to provide a first signal which varies as a function of the face temperature;
• examining the first signal for an indication of a limit cycle oscillation;
• and
• upon recognizing that a limit cycle oscillation has occurred, increasing the film thickness by a predetermined amount, thus providing seal assembly operation at an optimum film thickness.

The method of using a data processor with a memory array in controlling a mechanical seal assembly having two faces and fluid adjacent the faces, one face being displaceable with respect to the other face to adjust the gap and thus regulate the film thickness of the fluid between the faces, comprising the steps of:

• initiating seal assembly operation with a given film thickness which produces excessive leakage;
• sensing one parameter of the system to provide a first signal which varies as a function of said one parameter;
• examining the first signal for an indication of a given phenomenon;
• and
• upon recognizing that a given phenomenon has occurred, increasing the film thicknes by a predetermined amount, thus providing seal assembly operation at an optimum film thickness.