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.

A compressor operable in a heat pump mode of a refrigerant circuit includes a compression space in which a refrigerant is compressed. The compression space includes a discharge port and an injection port. A discharge chamber is fluidly coupled to the compression space by the discharge port. An injection chamber is fluidly coupled to the compression space by the injection port. A discharge recirculation pathway selectively provides fluid communication between the discharge chamber and the injection chamber. An injection of the recirculated refrigerant into the compression space through the injection port results in an increase in pressure, and hence temperature, of the refrigerant when discharged to the discharge chamber. The increased temperature of the discharged refrigerant increases a heating capacity of a condenser of the associated refrigerant circuit.

A compressor operable in a heat pump mode of a refrigerant circuit includes a compression space in which a refrigerant is compressed. The compression space includes a discharge port and an injection port. A discharge chamber is fluidly coupled to the compression space by the discharge port. An injection chamber is fluidly coupled to the compression space by the injection port. A discharge recirculation pathway selectively provides fluid communication between the discharge chamber and the injection chamber. An injection of the recirculated refrigerant into the compression space through the injection port results in an increase in pressure, and hence temperature, of the refrigerant when discharged to the discharge chamber. The increased temperature of the discharged refrigerant increases a heating capacity of a condenser of the associated refrigerant circuit.

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.

Oil-injected multistage compressor device including a low-pressure compressor element (2) with a gas inlet (4a) for gas to be compressed and a gas outlet (5a) for low-pressure compressed gas and a high-pressure stage compressor element (3) with a gas inlet (4b) for low-pressure compressed gas and a gas outlet (5b) for high-pressure compressed gas. The gas outlet (5a) of element (2) is connected to inlet (4b) of element (3) via a conduit (6). The conduit (6) has a regulatable intercooler (9) configured to regulate the temperature at the gas inlet (4b) of the high-pressure stage compressor element (3) so that it is above the dew point. The intercooler (9) includes a regulatable air cooler and/or a regulatable water cooler, and is configured to adjust the temperature of the air or water by using a bypass conduit (16) and/or by screening off part of the intercooler (9).

Oil-injected multistage compressor device including a low-pressure compressor element (2) with a gas inlet (4a) for gas to be compressed and a gas outlet (5a) for low-pressure compressed gas and a high-pressure stage compressor element (3) with a gas inlet (4b) for low-pressure compressed gas and a gas outlet (5b) for high-pressure compressed gas. The gas outlet (5a) of element (2) is connected to inlet (4b) of element (3) via a conduit (6). The conduit (6) has a regulatable intercooler (9) configured to regulate the temperature at the gas inlet (4b) of the high-pressure stage compressor element (3) so that it is above the dew point. The intercooler (9) includes a regulatable air cooler and/or a regulatable water cooler, and is configured to adjust the temperature of the air or water by using a bypass conduit (16) and/or by screening off part of the intercooler (9).

A portable vacuum pump with a lubricating oil system having a quick oil change system. The oil change system includes at least two containers of oil and a switch mechanism operable to initially place the first container in fluid communication with the vacuum pump to serve as the primary oil reservoir while isolating the second container from such fluid communication. Then in a snap action, the switch mechanism can be flipped to place the second container with clean oil in fluid communication with the vacuum pump to serve as the primary oil reservoir and isolate the first container from fluid communication when its oil becomes dirty, all while the vacuum pump is still operating to evacuate an AC/R system. The first container can then be removed, refilled with clean oil, and returned in place and the switch mechanism flipped back to it when the second container of oil becomes dirty.

A dry type primary vacuum pump is provided, including at least two pumping stages mounted in series between a suction and a discharge of the pump; two rotors extending in the pumping stages and being configured to rotate synchronously in a reverse direction to drive a gas to be pumped between the suction and the discharge; an injection device configured to distribute a purge gas in at least one pumping stage, the injection device including at least one injector and at least one injection valve with an on or off control configured to be interposed between a purge gas supply source and the injector; and a control device configured to control opening and closing of the injection valve to inject a purge gas by successive pulses into the at least one pumping stage. A method for controlling the injection of a purge gas the vacuum pump is also provided.

A dry type primary vacuum pump is provided, including at least two pumping stages mounted in series between a suction and a discharge of the pump; two rotors extending in the pumping stages and being configured to rotate synchronously in a reverse direction to drive a gas to be pumped between the suction and the discharge; an injection device configured to distribute a purge gas in at least one pumping stage, the injection device including at least one injector and at least one injection valve with an on or off control configured to be interposed between a purge gas supply source and the injector; and a control device configured to control opening and closing of the injection valve to inject a purge gas by successive pulses into the at least one pumping stage. A method for controlling the injection of a purge gas the vacuum pump is also provided.

A pump device includes a rotating body, a pump housing including a suction port and a discharge port, and a relief valve. In the pump device, a fluid is sucked from the suction port and discharged from the discharge port by rotation of the rotating body. The relief valve includes a valve body and a biasing member. The discharge port includes an one end in a direction in which the discharge port extends. The one end is shallower than a middle portion of the discharge port. The pump housing includes a relief flow path through which the fluid flows when the relief valve opens. The relief flow path is provided so as to be open to a groove bottom surface of the one end of the discharge port.