A pressure relief arrangement in refrigerant circuits with one high-pressure side and one low-pressure side, which is characterized in that the high-pressure side is fluidically connected with the low-pressure side of the refrigerant circuit via an overpressure relief device, wherein the overpressure relief device causes pressure reduction of the overpressure in the case of overpressure on the high-pressure side and fluid flows from the high-pressure side to the low-pressure side of the refrigerant circuit.

This disclosure is directed to systems and methods for controlling compressor motors, particularly varying the operation parameters of the motor to provide heat to a lubricant of the motor. The operation parameters include one or more of a pulse width modulation switching frequency, a pulse width modulation frequency switching pattern, or a torque/amp ratio of a drive of the compressor. The efficiency of the motor may be reduced to provide heat, with the heat improving lubricant quality and drive efficiency, to increase an overall efficiency of compressor operations. Methods may include determining a lubricant quality, and determining operational parameters that improve lubricant quality.

A leak detector is provided for leak-testing objects that are to be tested by spraying tracer gas, the leak detector including: a detection inlet configured to be connected to an object that is to be tested; a pumping device including a vacuum line connected to the detection inlet, a rough-vacuum pump connected to the vacuum line, and a turbomolecular vacuum pump connected to the vacuum line, a delivery of which is connected to the rough-vacuum pump; and a gas detector connected to the turbomolecular vacuum pump, the pumping device further including an ancillary pump connected to the rough-vacuum pump and being configured to lower an ultimate-vacuum pressure of tracer gas in the rough-vacuum pump. A leak detection method for leak-testing objects that are to be tested by spraying tracer gas is also provided.

A leak detector is provided for leak-testing objects that are to be tested by spraying tracer gas, the leak detector including: a detection inlet configured to be connected to an object that is to be tested; a pumping device including a vacuum line connected to the detection inlet, a rough-vacuum pump connected to the vacuum line, and a turbomolecular vacuum pump connected to the vacuum line, a delivery of which is connected to the rough-vacuum pump; and a gas detector connected to the turbomolecular vacuum pump, the pumping device further including an ancillary pump connected to the rough-vacuum pump and being configured to lower an ultimate-vacuum pressure of tracer gas in the rough-vacuum pump. A leak detection method for leak-testing objects that are to be tested by spraying tracer gas is also provided.

A method for monitoring an oil-injected screw compressor configured to compress aspirated air by returning oil from an oil separator vessel (11) to a compression chamber (12) of a compressor block (30), for condensate formation in the oil circuit due to a too low compression discharge temperature (VET), determines a water inlet mass flow {dot over (m)}.sub.ein(t) and a water outlet mass flow {dot over (m)}.sub.aus(t) for a point in time t and determines generated condensate flow Δ{dot over (m)}.sub.w(t)={dot over (m)}.sub.ein(t)−{dot over (m)}.sub.aus(t) on the basis of difference formation.

A method for monitoring an oil-injected screw compressor configured to compress aspirated air by returning oil from an oil separator vessel (11) to a compression chamber (12) of a compressor block (30), for condensate formation in the oil circuit due to a too low compression discharge temperature (VET), determines a water inlet mass flow {dot over (m)}.sub.ein(t) and a water outlet mass flow {dot over (m)}.sub.aus(t) for a point in time t and determines generated condensate flow Δ{dot over (m)}.sub.w(t)={dot over (m)}.sub.ein(t)−{dot over (m)}.sub.aus(t) on the basis of difference formation.

A fluid pump with a housing, a fluid duct which is provided in the housing, a temperature sensor which is assigned to the fluid duct in order to detect the temperature of a medium situated therein, and a metal thermally conductive element.

A fluid pump with a housing, a fluid duct which is provided in the housing, a temperature sensor which is assigned to the fluid duct in order to detect the temperature of a medium situated therein, and a metal thermally conductive element.

A sensor assembly for use in an apparatus comprising at least one moving part and at least one stationary part is provided. The assembly comprises a probe and means for mounting the sensor to a stationary part of the apparatus. The probe comprises a portion of an incomplete circuit which, when completed, produces a signal. In use, when the probe is engaged by a moving part of the apparatus, a signal is produced. A vacuum pump or a compressor pump comprising the sensor and a method for preventing failure of an apparatus are also provided.

A sensor assembly for use in an apparatus comprising at least one moving part and at least one stationary part is provided. The assembly comprises a probe and means for mounting the sensor to a stationary part of the apparatus. The probe comprises a portion of an incomplete circuit which, when completed, produces a signal. In use, when the probe is engaged by a moving part of the apparatus, a signal is produced. A vacuum pump or a compressor pump comprising the sensor and a method for preventing failure of an apparatus are also provided.