A method is for surveillance of an operating state of a pumping device connected to a process chamber in order to determine a failing operating state of the pumping device. The pumping device includes at least one rough-vacuum pump including a motor for driving the rough-vacuum pump and a variable speed drive to control the rotation speed of the motor, to receive a first input parameter corresponding to a set point frequency and a second input parameter corresponding to a motor current, and to deliver to the motor an output parameter corresponding to a control frequency. A failing operating state is determined when in steady-state operation the difference between the first input parameter and the output parameter is equal to or exceeds 10% of the first input parameter for a predetermined time greater than 3 seconds. The method can be implemented in a pumping device and an installation.

A method of treating, tuning, assembling, and/or overhauling a twin rotor device includes applying a coating material on an internal set of working surfaces of the twin rotor device when at least partially assembled. The coating may be factory or field applied to a new or used twin rotor device. The working surfaces may be uncoated or previously coated and may be built-up as the coating material forms a coating on at least some of the working surfaces. Manufacturing variations of a pair of rotors and a housing may be compensated by the coating. One or more performance characteristics of the twin rotor device may be improved by the coating, and variation between a series of twin rotor device may be reduced or substantially eliminated. The coating may reduce internal leakage and increase volumetric efficiency of the twin rotor device. The twin rotor device may be a supercharger 200, a screw compressor 1200, or other twin rotor device.

Integrated rotary positive-displacement machinery, for example compressors and/or vacuum pumps, include a compressor core equipped with at least one shunt pulsation trap and at least one absorptive silencer integrated together along with other compressor components (such as inlet/outlet pulsation dampeners, gas filters, safety valves, etc.) into a unit or package with a reduced pulsation, noise, energy consumption, and size and weight. Some embodiments further include at least one 4-way valve and corresponding piping so that the same positive-displacement machine can be operated to selectively provide vacuum and pressure by operation of the valve and piping.

A twin shaft pump may include two cooperating rotors configured to rotate in opposite directions about parallel axes of rotation; a stator comprising a stator bore in which the rotors are mounted to rotate. The stator bore includes a central part between the two axes of rotation, and an outer part outside of the two axes, the rotors being configured to have cooperating dimensions with the stator bore such that an outer edge of each rotor that is remote from the other rotor seals with the stator bore when rotating in at least a portion of the outer part. A fluid inlet is provided in the stator bore, at least a portion of the fluid inlet being in the central part of the stator bore between the axes of rotation. A fluid outlet is provide in an opposing surface of the stator bore, the fluid outlet being in the central part of the stator bore. The fluid inlet and fluid outlet are arranged such that on rotation of the rotors, the rotors each move a pumping chamber between the fluid inlet and the fluid outlet; wherein at least a portion of the fluid inlet is arranged to extend beyond the central part of the stator bore.

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 rotary piston compressor/pump/blower includes a housing spatially limiting a working chamber, an intake connection for guiding fluid into the working chamber, a pressure connection for guiding the fluid out of the working chamber, and a rotor assembly having a first rotor rotatably arranged in a first working sub-chamber and a second rotor cooperating with the first rotor and rotatably arranged in a second working sub-chamber. The rotary piston compressor/pump/blower also includes a ventilation channel, formed in the housing and connected to the working chamber via a ventilation channel opening, for the temporally limited introducing of air into the working chamber, wherein the ventilation channel opening is open at least in sections, in particular completely open, in a compression phase.

A modularized integrated non-coaxial multiple chamber dry vacuum pump is formed by at least two modularized vacuum chambers that can be integrated into a solid multiple stage dry vacuum pump. These chambers are connected in serial to allow gas to pass through and be discharged directly to the atmosphere. Each chamber contains a pair of lobes of its own and at least one chamber does not share at least one coaxial axle with another chamber. At least two chambers do not share all co-axial(s) and can have their own power drive at different RPMs from either different motors or transmissions.

In a conventional screw compressor, two mating rotors which resemble screws are assembled in parallel with each other within a housing. These rotors are very costly to manufacture, and it is very difficult to extract all of the gas that has been compressed between the lobes of the rotor screws. This invention eliminates the twist of the lobes around the rotor of a conventional screw compressor. In this invention, the lobes are manufactured in line with the axis of the rotor (axially). As a result, the costs of manufacturing the rotors are reduced dramatically, and the natural tendency for the gas to be driven towards the center of the female rotor is taken advantage of, making it much easier to extract practically all of the gas that has been compressed between the lobes.

A multistage power saving vacuum device with a root vacuum pump in a first stage is used in condenser vacuuming of a fired power plant. A root vacuum pump is used in a first stage and then at least one second stage vacuum pump is used to further process the pumping gas so that the gas vented outside is compressed through multiple stages and thus volume of the gas to be vented out has reduced greatly so as to reduce power consumption. The multistage power saving vacuum device comprises a vacuum inlet gas-driving shut-off valve; a first root vacuum pump; at least one second vacuum pump serially connected to the first root vacuum pump; when there are more than one the second vacuum pumps, all the second vacuum pumps are serially connected. The multistage power saving vacuum device further comprises a last stage vacuum pump and a vapor separator.

A Rotary Claw Pump with at least one pair of intermeshing rotors has the same shape within a tolerance of 3% of the radii from edges to rotational centers. A convex portion of the claws has a nominal uniform rate of radius change with angle of rotation. There may be multiple stages wherein the thickness of each successive rotor pair maintains profile but has a thickness within 20% of the thickness of the first stage rotor pair multiplied by the inverse products of the compression ratios of the preceding stages. A discharge port is at least partially uncovered at any position of rotation from where intermeshing claw rotor tips are closest to where they are most distant. The discharge port is at least partially connected with a region connected with the rotor tips of both claws during rotation. The discharge port limits pressure increase in the region.