A magnetic bearing control apparatus and a vacuum pump which do not require a displacement sensor, which enable control with high accuracy, and which are small and low cost. A rate of change (di/dt) that is a time derivative of a current value I.sub.m flowing through an electromagnet varies in accordance with a magnitude of a displacement of a gap between a target member and the electromagnet. The rate of change (di/dt) can be obtained by detecting a voltage value V.sub.s that is generated at both ends of an inductive element. Therefore, by detecting the voltage value V.sub.s, the magnitude of the displacement of the gap can be estimated by calculation. Inductive elements are connected in series to electromagnets and the voltage V.sub.s between the inductive elements is detected by the differential input amplifier. A single period of switching of a PWM switching amplifier is constituted by a current control period of the electromagnet and a displacement detection period for detecting the rate of change (di/dt). In addition, the displacement detection period is further constituted by a current increase period and a current decrease period which are certain periods of time. The current increase period and the current decrease period are equal to each other.

A vacuum pump comprises: a base; a rotor shaft rotatably provided at the base; a rotor including rotor blades arranged in multiple stages and a rotor cylindrical portion, and attached to the rotor shaft; stationary blades each arranged between adjacent ones of the rotor blades, the stationary blades and the rotor blades forming a turbo exhaust portion; a stator forming, together with the rotor cylindrical portion, a screw groove exhaust portion; and a hexagon socket head cap screw configured to fix the stator to an upper surface of the base in a guiding path of the screw groove exhaust portion to which gas is guided from the turbo exhaust portion. The hexagon socket head cap screw is a bolt having a smaller height of a head portion than that of a hexagon socket head cap screw according to a provision of a country of use or an international organization.

According to one aspect of the present disclosure, a turbomachine (100) is provided. The turbomachine includes: a rotor extending in an axial direction and comprising a driven side configured to be connected to a driving unit and a second side opposite the driven side; a housing extending around at least a portion of the rotor, wherein a main flow path for a process fluid extends between the rotor and the housing; a sealing arrangement, particularly a dry gas seal, configured for sealing a gap between the rotor and the housing at the driven side of the rotor; and a first magnetic bearing supporting the second side of the rotor. A fluid passage for a portion of the process fluid extends from the main flow path through a bearing gap of the first magnetic bearing. According to a further aspect, a method of operating a turbomachine is described.

The present invention relates to a turbo-molecular vacuum pump comprising bearings for supporting the drive shaft and/or the rotor in relation to a pump body, wherein a first bearing is coupled to the rotor and disposed on supporting mount at the high vacuum side of the rotor and radial struts extend from the supporting mount and form an integral part of the body; the invention is characterised in that the radial struts comprise a hinge portion that can flex to allow relative movement of the inlet flange with respect to the supporting mount to reduce distortion effects.

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 vacuum valve connected to a vacuum pump, comprises: a valve plate to be openably/closably driven; a drive section configured to openably/closably drive the valve plate; a signal input section to which a pump information signal indicating an operation state of the vacuum pump is input; and a valve control section configured to control operation of the valve plate based on the input pump information signal.

A magnetic bearing device comprises a radial magnetic bearing configured to magnetically levitate and support a rotor shaft in a radial direction; an axial magnetic bearing configured to magnetically levitate and support, in an axial direction, a rotor disc rotatable together with the rotor shaft; and an axial displacement sensor disposed on a surface of an electromagnet core of the axial magnetic bearing facing the rotor disc and configured to detect axial displacement of the rotor disc.

Bobbins of an annular electromagnet each have a bobbin body that has a coil wire wound around an outer periphery thereof and is attached to a respective tooth of an annular stator core by having the corresponding tooth inserted therethrough. A first flange portion in a rectangular hallow shape is provided on an end surface of the bobbin body near the center of the annular stator core and a second flange portion in a rectangular hallow shape is provided on the other end surface of the bobbin body. A coil winding amount increasing means is formed at least on the first flange portion or the second flange portion and increases the amount of winding of the coil wire wound around the bobbin body.

In a vacuum pump, the lower Ra sensor target, the fourth spacer, and the Ra electromagnetic target are configured in this order, from the inlet port side toward the outlet port side, at the lower side of the shaft of the 5-axis control magnetic bearing Likewise, at the lower side of the stator, the lower Ra sensor and the lower Ra electromagnet are configured in this order, from the inlet port toward the outlet port. In other words, the lower Ra sensor is disposed above the lower Ra electromagnet. According to this configuration, the third spacer fixed above the lower Ra sensor target is shortened. As a result, the height of the 5-axis control magnetic bearing and the length of the stator column enclosing electrical components constituting the 5-axis control magnetic bearing is reduced, thereby reducing the overall height of the vacuum pump.

Provided are a vacuum pump, a magnetic bearing device, and a rotor that suppress swinging and vibration of a rotor. A vacuum pump includes, in the following order in the exhaust direction of a gas, the center of gravity of a rotor, an active radial bearing that supports the rotor in the radial direction in a non-contact manner by using a magnetic force, and a passive radial bearing that supports the rotor in the radial direction in a non-contact manner using a magnetic force.