In order to prevent excessive motor loading or system overheating due to the accumulation of particulate or dust, from SACVD type CVD processes, in the running clearances of the vacuum pump a vacuum pumping arrangement is provided having a plurality of vacuum pumping stages and comprising a first pump inlet through which process fluid from the vacuum chamber can enter the pump and pass through each of the pumping sections towards a pump outlet, and a second pump inlet through which process fluid can enter the pump and pass through only one or more pumping stages downstream of the most upstream pumping stage, wherein the apparatus configured to conveying process fluid from the vacuum chamber to the first pump inlet for pumping during the second processing step and conveying process fluid from the vacuum chamber to the second pump inlet for pumping during the first processing step.

The present disclosure relates to a dual-stage compressor, a control method thereof, and an air conditioning unit. The dual-stage compressor includes a low-pressure stage; a high-pressure stage connected in series with the low-pressure stage; and a volume ratio adjustment mechanism arranged at the high-pressure stage and configured to adjust the volume ratio of refrigerant compression at the high-pressure stage. When the final compression pressure of the compressor is lower or greater than the exhaust pressure, the volume ratio adjustment mechanism is operated to increase or reduce the volume ratio of refrigerant compression at the high-pressure stage so that the final compression pressure of the compressor is equal to the exhaust pressure, and overcompression and undercompression are improved to adapt to changes in external conditions, increase the energy efficiency of the compressor, and reduce the noise of the compressor.

A spiral compressor may include a stationary first spiral member and an orbiting second spiral member intermeshing with the first spiral member. The spiral compressor may include a pendulum slide mechanism that may have an inner ring and a stationary outer ring connected to the inner ring via a plurality of pendulums. The pendulum slide mechanism may include an eccentric member disposed on a radial inside of the inner ring with respect to a central access of the inner ring. The inner ring on an inner circumferential side may be drivingly connected to the eccentric member and on an outer circumferential side may be rigidly connected to the second spiral member. The second spiral member may transmit an orbiting motion in relation to the first spiral member via the pendulum slide mechanism when the eccentric member is driven.

In a scroll compressor, a first flow passage is formed in a fixed base plate and a frame to supply oil separated by an oil separating mechanism provided in a sealed container to an oil sump at the bottom of the sealed container. In the fixed base plate, a second flow passage is formed to supply the oil separated by the oil separating mechanism into a compression mechanism.

A two-stage rotary compressor for gas, in particular air. The compressor comprises a bottom plate and a head enclosing between them two compression stages. The compressor is characterized in that an interconnection device is arranged between the two compression stages, said device being suited to establish a communication “in series” or “in parallel”, to be selected by the manufacturer, between said two compression stages.

A two-stage rotary compressor for gas, in particular air. The compressor comprises a bottom plate and a head enclosing between them two compression stages. The compressor is characterized in that an interconnection device is arranged between the two compression stages, said device being suited to establish a communication “in series” or “in parallel”, to be selected by the manufacturer, between said two compression stages.

A vacuum exhaust system and method of evacuating a plurality of chambers is disclosed. The vacuum exhaust system is within a clean room and comprises: a plurality of branch process gas channels each configured to connect to a corresponding chamber and a shared process channel formed from a confluence of the branch channels and configured to provide a shared fluid communication path for process gas from each of the chambers to flow from the clean room to a process channel outside of the clean room. There is also a plurality of branch pumpdown channels each configured to connect to a corresponding chamber and a shared pumpdown channel formed from a confluence of the branch pumpdown channels and configured to provide a fluid communication path for fluid to flow from the clean room to a pumpdown channel outside of the clean room during pumpdown of at least one of the vacuum chambers.

A method of operating a vacuum pump system, the method including the steps of: operating a primary vacuum pump having a variable speed motor; connecting at least two secondary vacuum pumps in parallel with said primary vacuum pump; dividing the secondary vacuum pumps in groups, each group including at least one secondary vacuum pump; and assigning a priority for each of said groups. The method further includes the steps of measuring the inlet pressure p1, comparing the measured inlet pressure p1 with a predetermined pressure value p0, and if p1 is higher than p0, starting the secondary vacuum pump at a first predetermined startup load S.sub.startup,1 if it includes a fixed speed motor, and/or starting the secondary vacuum pump at a second predetermined startup load S.sub.startup,2, if it includes a variable speed motor.

A method of operating a vacuum pump system, the method including the steps of: operating a primary vacuum pump having a variable speed motor; connecting at least two secondary vacuum pumps in parallel with said primary vacuum pump; dividing the secondary vacuum pumps in groups, each group including at least one secondary vacuum pump; and assigning a priority for each of said groups. The method further includes the steps of measuring the inlet pressure p1, comparing the measured inlet pressure p1 with a predetermined pressure value p0, and if p1 is higher than p0, starting the secondary vacuum pump at a first predetermined startup load S.sub.startup,1 if it includes a fixed speed motor, and/or starting the secondary vacuum pump at a second predetermined startup load S.sub.startup,2, if it includes a variable speed motor.

A pumping installation includes at least one first positive-displacement machine and one second positive-displacement machine, as well as a control module, in which installation a gas is evacuated from an enclosed volume by means of the first positive-displacement machine and/or the second positive-displacement machine. The pumping installation includes at least one control valve controlled by the control module and a pressure sensor for sensing the value of the pressure at the outlet of the first positive-displacement machine and/or a temperature sensor for sensing the value of the temperature at the outlet of the first positive-displacement machine in order to control the flow of gas between the enclosed volume and the outlet of the pumping installation.