The invention relates to a displacement machine according to the spiral principle, in particular a scroll compressor or scroll expander, with a high-pressure chamber, a low-pressure chamber and an orbiting displacement spiral, which engages in a counter-spiral such that chambers are formed between the displacement spiral and the counter-spiral for receiving a working medium, wherein a counter-pressure chamber is formed between the low-pressure chamber and the displacement spiral. According to the invention a pressure regulating device which is fluidically connected to the counter-pressure chamber sets a pressure difference between the counter-pressure chamber and the low-pressure chamber by means of a set value specified by the computing unit.

A compressor system includes a screw compressor and a controller. The screw compressor includes a slide valve selectively actuatable between a first position and a second position to facilitate modulating a capacity of the screw compressor between fully-loaded and fully-unloaded. The controller is communicably coupled to the slide valve. The controller is configured to receive a chilled fluid temperature setpoint for a fluid in heat transfer communication with a refrigerant of the refrigeration circuit; receive temperature data indicative of a chilled fluid temperature of the fluid; determine a difference between the chilled fluid temperature and the chilled fluid temperature setpoint; and provide one of a load command and an unload command to the slide valve based the difference between the chilled fluid temperature and the chilled fluid temperature setpoint. According to an embodiment, the controller does not receive feedback from the screw compressor regarding a position of the slide valve.

A compressor system includes: a compressor having a suction side and a discharge side, wherein the compressor is operative to compress a gas using oil, wherein the suction side operates at a suction pressure and is operative to receive a the gas and the oil into the compressor; and wherein the discharge side is operative to discharge the compressed gas and the oil; a gas/oil separator tank operative to store oil separated from the compressed gas for subsequent use by the compressor; a supplemental oil reservoir in fluid communication with the suction side; and a valve operative to, when opened, expose the supplemental oil reservoir to the suction pressure of the suction side of the compressor, and draw oil from the supplemental oil reservoir by suction into the suction side of the compressor.

Systems and methods are used to control operation of a rotary compressor of a refrigeration system to improve efficiency by varying the volume ratio and the speed of the compressor in response to current operating and load conditions. The volume of the axial and/or radial discharge ports of the compressor can be varied to provide a volume ratio corresponding to operating conditions. In addition, permanent magnet motors and/or control of rotor tip speed can be employed for further efficiency gains.

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.

Systems and methods are used to control operation of a rotary compressor of a refrigeration system to improve efficiency by varying the volume ratio and the speed of the compressor in response to current operating and load conditions. The volume of the axial and/or radial discharge ports of the compressor can be varied to provide a volume ratio corresponding to operating conditions. In addition, permanent magnet motors and/or control of rotor tip speed can be employed for further efficiency gains.

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 compressor includes a housing, a partition, a first scroll, a second scroll, and a valve assembly disposed within the second scroll. The valve assembly includes a valve housing, a valve body, and a first biasing member configured to displace the valve body from a first position to a second position relative to the valve housing. When in the first position, the valve body inhibits fluid communication between a fluid source and one of a series of compression pockets formed by the first and second scroll. When in the second position, the valve body allows fluid communication between the conduit and one or more of the series of compression pockets. The valve body is displaceable between the first and second positions in response to a change in operating temperature of the compressor.

A variable displacement pump is provided which better distributes stress across the rotor structure thereby reducing the risk of the rotor cracking and/or failing. The variable displacement pump includes a housing, a vane control ring, a rotor, a plurality of vanes, a slider ring, a biasing means, and a regulator valve. The housing defines an inlet port and a discharge port. The rotor may be rotationally driven by a drive shaft and coaxially aligned with the drive shaft. The rotor may define a plurality of primary ribs and a plurality of corresponding secondary ribs with an aperture defined between each primary rib and secondary rib. Each primary rib defines a primary rib thickness and each secondary rib defines a secondary rib thickness which is less than the primary rib thickness.

Systems and methods are used to control operation of a rotary compressor of a refrigeration system to improve efficiency by varying the volume ratio and the speed of the compressor in response to current operating and load conditions. The volume of the axial and/or radial discharge ports of the compressor can be varied to provide a volume ratio corresponding to operating conditions. In addition, permanent magnet motors and/or control of rotor tip speed can be employed for further efficiency gains.