A monitoring apparatus is adapted to monitor lubricant in a hydraulic fracturing pump system, and includes a gateway and one or more sensors configured to be in communication with the gateway. The one or more sensors are configured to measure quality of the lubricant, a pressure of the lubricant, and a temperature of the lubricant. The gateway is configured to receive sensor data associated with the quality of the lubricant, the pressure of the lubricant, and the temperature of the lubricant. To monitor the lubricant, the gateway is configured to: store the sensor data on the non-transitory computer readable medium; transmit to another computing device the sensor data and/or representative data based on the sensor data; visually indicate a status of the quality of the lubricant; visually indicate a status of the pressure of the lubricant; visually indicate a status of the temperature of the lubricant; or any combination thereof.

In order to improve a refrigerant compressor, including a compressor unit having a compressor housing and at least one compressor element that is arranged in the compressor housing, for compressing refrigerant, and further including a drive unit having a drive housing and an electric motor that is arranged in the drive housing and connector terminals that are arranged on the drive housing, for the electric motor, and further including an electronic functional unit, such that the connection between the refrigerant compressor and the electronic functional unit is achievable as simply as possible, it is proposed that the connector terminals should be provided in a housing that is arranged on the drive housing, and that an electronic functional unit which performs at least one compressor function should be provided in the housing.

The present disclosure provides a compressor system operable for compressing a working fluid such as air. A conditioner is positioned upstream of the compressor to reduce the humidity and in some embodiments may control a temperature of the working fluid entering the compressor. A working fluid aftercooler and a lubricant cooler is positioned downstream of the compressor. A first heat exchange system directs water from a source through the conditioner and then to the aftercooler and oil cooler in parallel. A second heat exchange system directs oil from the compressor to the oil cooler and then to a regenerator prior to reentry into the compressor. A control system with one or more control valves is configured to provide oil to the compressor at a target temperature defined to ensure that the temperature of the discharged compressor is above a pressure dew point temperature.

A mixing valve arrangement for a hydraulic system is provided with a medium cavity, in which a mixing cylinder, a first and a second inlet chamber as well as an outlet are provided. A mixing piston is axially mounted and movable in the mixing cylinder, provided with a flow path with an inlet opening, a variable cross-section of said inlet opening culminating into the first and/or the second inlet chamber, according to the axial position of the mixing piston, and with an outlet opening culminating in the outlet of the mixing cylinder. A thrust rod is axially mounted and movable and connected to the mixing piston, to change the axial position thereof. A drive is connected as an actuator to the thrust rod, for the axial movement of the same. The drive is an electrical motor, which is completely arranged inside the medium cavity.

A system includes a sensor and a controller for a refrigeration or HVAC system having a compressor. The sensor senses a temperature of the compressor during operation of the compressor. The controller is configured to determine a rate of change of the temperature relative to time and to perform one or more procedures to protect the compressor based on the rate of change of the temperature. The one or more procedures to protect the compressor include shutting down the compressor, throttling a pressure regulator valve of an evaporator associated with the compressor, adjusting an expansion valve associated with the evaporator, reducing speed of the compressor, and partially or wholly unloading the compressor.

A linear compressor according to the present disclosure may include a cylinder provided with at least one groove, a piston reciprocating within the cylinder, a motor configured to provide a driving force to move the piston within the cylinder, an inverter configured to perform a switching operation to transmit electric power to the motor, and a controller configured to receive temperature information from the electronic device and control the inverter to preheat the motor based on the received temperature information.

An arrangement (100) for specifying the pressure (64), produced by a pump (30) driven by an electric motor (31), includes a processor (116) which derives a target pressure value (62, 118) from an internal torque value (114) and a loss torque (108). The arrangement (100) further derives (112) the internal torque value (114) from a motor current value (110) and a motor constant k.sub.e.

A monitoring apparatus is adapted to monitor lubricant in a hydraulic fracturing pump system, and includes a gateway and one or more sensors configured to be in communication with the gateway. The one or more sensors are configured to measure quality of the lubricant, a pressure of the lubricant, and a temperature of the lubricant. The gateway is configured to receive sensor data associated with the quality of the lubricant, the pressure of the lubricant, and the temperature of the lubricant. To monitor the lubricant, the gateway is configured to: store the sensor data on the non-transitory computer readable medium; transmit to another computing device the sensor data and/or representative data based on the sensor data; visually indicate a status of the quality of the lubricant; visually indicate a status of the pressure of the lubricant; visually indicate a status of the temperature of the lubricant; or any combination thereof.

A refrigerant compressor for refrigeration plants having a compressor unit driven by a drive unit. At least one of the compressor and drive units has a control unit which is controllable by delivery rate control system to control the refrigerant compressor at different delivery rates. An external delivery rate setpoint value is communicated to the delivery rate control system to prevent critical operating states. The delivery rate control system is configured to acquire, via a sensor, a compressor unit reference temperature. The delivery rate control system is configured to ascertain an operating state value group to acquire an operating state of the refrigerant compressor, and specify a delivery rate for operation of the refrigerant compressor outside of the critical operating states, if the value of the ascertained operating state value group based upon the compressor reference temperature permits a critical operating state of the refrigerant compressor.

A computer-implemented method for detecting condensate in an oil system of a compressor, having an inlet and an outlet. The method incudes the steps of: determining the humidity at the inlet and at the outlet or downstream of the outlet of the compressor; determining the amount of water vapor that enters and exits the compressor based on the humidity determined at the inlet and the outlet or downstream of the outlet; determining the amount of condensate that remains in the compressor by determining the difference between the amount of condensate that enters and exits the compressor; storing the amount of condensate that remains; and repeating the aforementioned steps at regular intervals and storing the amount of condensate and how long said condensate remains in the compressor.