A vacuum pump, vacuum pump arrangement and method are disclosed. The vacuum pump includes at least one rotor; and a stator, an inlet for receiving gas during operation; and an exhaust for exhausting the gas. The vacuum pump includes a shaft extending through a centre of said pump and comprising a plate mounted on an end of the shaft towards the inlet. The vacuum pump includes control circuitry configured to control an axial position of the plate, a change in axial position of the plate providing a change in inlet conductance of gas to the vacuum pump. The plate is mounted such that it extends beyond the inlet in at least some axial positions of the rotor such that the plate is not on the same side of the inlet as the stator.

Decane (C10H22) is sprayed as a mist from spray nozzles toward a rotor blade via a supply pipe and communication passages. Since decane has a boiling point of 174° C. at atmospheric pressure, the decane is a liquid at normal temperature and normal pressure. On the other hand, the pressure inside a turbomolecular pump is in a substantially vacuum state of about 100 Pa, and the boiling point of decane at this pressure is 14° C. Thus, although the pressure is high and the decane is in a liquid state until the decane is sprayed, when the decane adheres to surfaces of the rotor blades and the temperature of the decane rises, the decane vaporizes. At this moment, since the amount of heat of the rotor blades is consumed as heat of vaporization, the rotor blades can be cooled.

A vacuum pump and a control device are capable of accurately determining timing of rotor blade replacement by creating an index which allows a degree of fatigue of a rotor blade to be determined quantitatively and easily. A motor current value output from a motor drive control portion is input to a time count processing portion, and time in which a current value of a rotating body remains in a range of a stage is totalized for each stage of the current value in the time count processing portion. A rotor blade temperature value output from a rotor blade temperature measurement portion is also input to the time count processing portion. A one-minute average value of the rotor blade temperature value acquired by sampling is calculated. For each stage of the rotor blade temperature value, time in which the average value remains in a range of the stage is totalized.

A pressure difference of liquid is generated between an upper end and a lower end of a thread groove by the action of a thread groove pump formed between the thread groove and a lower end wall portion of a rotating rotor shaft. As a result, liquid of a bottom space is sucked up and passes through a hollow hole and is discharged to the outside of the rotor shaft through communication holes. The discharged liquid passes through the inside of a hub of a rotating body and reaches an extension member where it is sprayed radially in the form of droplets from a protrusion. The droplets are received by a partition wall. Due to the presence of a protrusion in an upper portion of the partition wall, the droplets cannot cross over the partition wall. The accumulated liquid drops through a communication hole to the bottom space.

A drag pump for pumping gas and a set of vacuum pumps including the drag pump are disclosed. The drag pump comprises: a rotor configured to rotate within a stator component and to drive a gas to be pumped from a gas inlet to a gas outlet; magnetic bearings for rotatably mounting the rotor within the pump; wherein at least a portion of the rotor and stator component configured to contact the gas to be pumped are configured for operation at temperatures above 130° C.

A magnetic bearing device includes a magnetic bearing including a plurality of electromagnets, a displacement sensor configured to output an output signal in accordance with a displacement of a shaft, and a controller configured to control the electromagnets. The controller compensates for a change in levels of the output signal, the change occurring in accordance with a change in ambient temperature around the displacement sensor, based on one or more reference values correlating with the change in levels of the output signal. The one or more reference values are detected for use in controlling the rotary electric machine, a fluid machine system including the rotary electric machine, or an apparatus including the fluid machine system.

A vacuum pump and a sensor target are provided that are inexpensive and widen the linearity range of the sensor sensitivity as compared to a configuration in which a ferromagnetic material is used for the sensor target of a displacement sensor, and also reduce the possibility of touch down even when a disturbance occurs. An axial displacement sensor 109 includes a shaft 109A, which is extended through and fixed to the central section of a holder 5 holding an axial electromagnet 106, and a bobbin 109B, which is coupled to the upper end of the shaft 109A and around which a coil 7 is wound. A shaft end portion 113B, which has the shape of a small-diameter column, projects from the lower end of a rotor shaft 113 and is separated from the coil 7 by a gap 2. An external thread is formed on the outer circumference of the shaft end portion 113B so that a nut 19, which has an internal thread on the inner side, is engaged with the shaft end portion 113B. The area where the internal thread is formed does not extend over the entire thickness of the nut 19 and extends only partially. That is, the nut 19 has a threaded hole 19A opening only at the upper end. The nut 19 is made of a single material of low-carbon steel.

The present invention relates to a vacuum pump, in particular to a turbomolecular pump, having at least one pump stage and having a pressure determination unit for determining a pressure present at a suction side of the vacuum pump, said pump comprising a measurement device, with a measurement tap of the measurement device being provided in the region of the pump stage or downstream of the pump stage.

Oil feed nut for providing a lubricant to a bearing of a vacuum pump comprising a first end and an opposite second end and being configured to be connected to a shaft of the vacuum pump. Further, the oil feed nut comprising an oil feeding element extending between the first end and the second end, wherein the oil feeding element has an increasing diameter towards the second end to create an increasing rotational force acting on the lubricant in order to convey the lubricant towards the second end, and a bearing journal element having a cylindrical surface configured to be received in a back-up bearing of the vacuum pump. Therein, the back-up bearing is arranged in a cartridge of an oil reservoir.

A pump bearing holder has a carrier portion configured to carry a static set of magnets of a pump magnetic bearing and a support portion extending outwardly of the carrier portion to connect with a pump casing such that the pump bearing holder spans an inlet provided in the pump housing. The support portion defines a plurality of internal through-passages that, in use, allow a gas flowing through the inlet to flow through the support portion.