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.

One embodiment of a method for operating an internal combustion engine under a pressure less than atmospheric pressure includes the steps of positioning a vacuum pump such that said vacuum pump is in fluid communication with a crankcase of said internal combustion engine, connecting a discharge of said vacuum pump to a separator, wherein a portion of said discharge of said vacuum pump condenses in said separator, connecting a vapor discharge of said separator to a filter, wherein said filter removes a portion of volatile organic compounds from said vapor discharge, and venting said filter to an ambient atmosphere.

A hydraulic pump includes a casing, an impellor pump comprising a rotor that is rotationally mobile with respect to the casing about a first axis, the rotor comprising several blades in helix form, a transition zone belonging to the casing and having, on the side of the impellor pump, a ramp in helix form developing in the same direction as the helix form of the blades, a trochoid pump comprising a rotor with outer toothing secured to the rotor of the impellor pump, and a rotor with internal toothing that is rotationally mobile with respect to the casing about a second axis parallel to and offset from the first axis, the trochoid pump being fed by the impellor pump through the transition zone running along the ramp.

A screw spindle pump, comprising a pump housing having a lead screw received therein and at least one running spindle which meshes with said lead screw, as well as a connector housing which is placed onto the pump housing and has a suction connector and a pressure connector, the two latter fluidically communicating with a suction inlet and a pressure outlet of the pump housing, wherein the connector housing is composed of a first housing part and a second housing part, one of the two latter having the suction connector and the other having the pressure connector, both said housing parts being rotatable relative to the pump housing and both being rotatable relative to one another.

A rotor is shown with an asymmetrical structure for a pump, wherein the rotor includes at least one cutting edge and at least one rounded edge, as well as the pump as such including one or more rotor(s). The rotor (1) has a first circular element (4) where a material-moving cavity (5) is provided in the first circular element (4).

A screw spindle pump, comprising a pump housing having a lead screw received therein and at least one running spindle which meshes with said lead screw, as well as a connector housing which is placed onto the pump housing and has a suction connector and a pressure connector, the two latter fluidically communicating with a suction inlet and a pressure outlet of the pump housing, wherein the connector housing is composed of a first housing part and a second housing part, one of the two latter having the suction connector and the other having the pressure connector, both said housing parts being rotatable relative to the pump housing and both being rotatable relative to one another.

A screw compressor for a heating, ventilation, and air conditioning (HVAC) system. The screw compressor includes a housing having an inlet end and an outlet end for refrigerant to pass into and out of the housing. A motor is within the housing. A plurality of screw sets are arranged about the motor. The screw sets receive refrigerant entering through the inlet, compress the refrigerant between meshed rotors of the plurality of screw sets, and direct refrigerant out of the housing through the outlet end of the housing.

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 screw compressor for a heating, ventilation, and air conditioning (HVAC) system. The screw compressor includes a housing having an inlet end and an outlet end for refrigerant to pass into and out of the housing. A motor is within the housing. A plurality of screw sets are arranged about the motor. The screw sets receive refrigerant entering through the inlet, compress the refrigerant between meshed rotors of the plurality of screw sets, and direct refrigerant out of the housing through the outlet end of the housing.

A hydraulic pump includes a casing, and an impeller pump having a rotor that is rotationally mobile with respect to the casing about a first axis. The rotor includes several blades in helix form, a transition zone belonging to the casing and having, on the side of the impeller pump, a ramp in helix form developing in the same direction as the helix form of the blades. A trochoid pump includes a rotor with outer toothing secured to the rotor of the impeller pump. A rotor with internal toothing is rotationally mobile with respect to the casing about a second axis parallel to and offset from the first axis. The trochoid pump is fed by the impeller pump through the transition zone running along the ramp.