A method and computer program product for defining a PWM drive signal having a defined voltage potential. The PWM drive signal has a plurality of “on” portions and a plurality of “off” portions that define a first duty cycle for regulating, at least in part, a flow rate of a pump assembly. At least a portion of the “on” portions of the PWM drive signal are pulse width modulated to define a second duty cycle for the at least a portion of the “on” portions of the PWM drive signal. The second duty cycle regulates, at least in part, the percentage of the defined voltage potential applied to the pump assembly.

A method and computer program product for defining a PWM drive signal having a defined voltage potential. The PWM drive signal has a plurality of “on” portions and a plurality of “off” portions that define a first duty cycle for regulating, at least in part, a flow rate of a pump assembly. At least a portion of the “on” portions of the PWM drive signal are pulse width modulated to define a second duty cycle for the at least a portion of the “on” portions of the PWM drive signal. The second duty cycle regulates, at least in part, the percentage of the defined voltage potential applied to the pump assembly.

A retainer nut assembly for a fluid end of a pump system includes a fastener with a generally cylindrical configuration, first and second ends, external threads configured to engage corresponding threads of a fluid end block, and a cavity formed at the first end. A suction cap is configured to sealingly fit to the fluid end block. A load piston is movably disposed in the cavity adjacent the suction cap. A bore is formed through the fastener in communication with the cavity and provided with hydraulic fluid. A pressure piston is movably disposed in the bore. A threaded passageway is formed through the fastener in communication with the bore and open to the second end. A locking bolt is disposed in the threaded passageway and, when inserted into the threaded passageway, contacts the pressure piston and generates fluid pressure on the load piston.

A retainer nut assembly for a fluid end of a pump system includes a fastener with a generally cylindrical configuration, first and second ends, external threads configured to engage corresponding threads of a fluid end block, and a cavity formed at the first end. A suction cap is configured to sealingly fit to the fluid end block. A load piston is movably disposed in the cavity adjacent the suction cap. A bore is formed through the fastener in communication with the cavity and provided with hydraulic fluid. A pressure piston is movably disposed in the bore. A threaded passageway is formed through the fastener in communication with the bore and open to the second end. A locking bolt is disposed in the threaded passageway and, when inserted into the threaded passageway, contacts the pressure piston and generates fluid pressure on the load piston.

Systems and methods for controlling a pump system for use in negative pressure wound therapy are described herein. In some embodiments, a method for controlling a pump system includes causing provision of negative pressure, via a flow path, to a wound dressing configured to be positioned over a wound, the flow path configured to fluidically connect the pump system to the wound dressing, measuring a first pressure value in the flow path at a first time, measuring a second pressure value in the flow path at a second time, calculating a first rate of pressure change using the first and second pressure values, and in response to determining that the calculated first rate of pressure change satisfies a threshold rate of change, providing an indication that the wound dressing is full, wherein the method is performed under control of a controller of the pump system.

Systems and methods for controlling a pump system for use in negative pressure wound therapy are described herein. In some embodiments, a method for controlling a pump system includes causing provision of negative pressure, via a flow path, to a wound dressing configured to be positioned over a wound, the flow path configured to fluidically connect the pump system to the wound dressing, measuring a first pressure value in the flow path at a first time, measuring a second pressure value in the flow path at a second time, calculating a first rate of pressure change using the first and second pressure values, and in response to determining that the calculated first rate of pressure change satisfies a threshold rate of change, providing an indication that the wound dressing is full, wherein the method is performed under control of a controller of the pump system.

A machine monitoring system automatically determines an optimal trigger angle for monitoring the rod drop of a reciprocating compressor, and sets the trigger angle configuration value accordingly. A key pulse is monitored using a key phase sensor, the amplitude of the rod drop transducer voltage versus time (or rotation angle) is analyzed, and a position of the minimal change in slope of the rod drop transducer voltage signal relative to the key mark is determined. The optimal trigger angle is determined based on this temporal position, the current speed and the configured piston angle. The optimal trigger angle is provided to the machine monitoring system for configuration. The system thereby relieves the service engineer from having to test several trigger angles with manually-operated test instruments to determine the optimal trigger angle.

A machine monitoring system automatically determines an optimal trigger angle for monitoring the rod drop of a reciprocating compressor, and sets the trigger angle configuration value accordingly. A key pulse is monitored using a key phase sensor, the amplitude of the rod drop transducer voltage versus time (or rotation angle) is analyzed, and a position of the minimal change in slope of the rod drop transducer voltage signal relative to the key mark is determined. The optimal trigger angle is determined based on this temporal position, the current speed and the configured piston angle. The optimal trigger angle is provided to the machine monitoring system for configuration. The system thereby relieves the service engineer from having to test several trigger angles with manually-operated test instruments to determine the optimal trigger angle.

A flow control device is disclosed. The flow control device includes a solenoid, the solenoid including an armature. Also, a piston connected to the armature. The piston includes a primary orifice. The piston having an open position and a closed position. A piston spring connected to the piston is also includes and at least one secondary orifice. The movement of the piston to the open position at least partially opens the at least one secondary orifice and the movement of the piston to the closed position at least partially closes the at least one secondary orifice. The movement of the armature actuates the piston movement and controls fluid flow from the primary orifice through the at least one secondary orifice.

Apparatus and methods for measuring backlash of a gear train of a pump unit for pumping a fluid. An example method may include locking a crankshaft of the pump unit such that the crankshaft cannot rotate. The method may further include commencing operation of a processing device to receive rotational position measurements indicative of rotational position of an output shaft of a prime mover, cause the prime mover to rotate the output shaft in a first direction until the output shaft reaches a first rotational position, and cause the prime mover to rotate the output shaft in a second direction until the output shaft reaches a second rotational position. The processing device may then determine backlash of the gear train by determining rotational distance between the first rotational position of the output shaft and the second rotational position of the output shaft.