A thread groove pump portion, which is an exhaust element, is structured such that a Siegbahn structure is attached onto a cylindrical thread, and such that respective parts are connected to each other at this attachment section. A flow channel of the Siegbahn portion and a flow channel of the cylindrical thread (the thread groove pump portion) are connected to each other so as to substantially form a right angle when viewed from an axis direction of the vacuum pump, thus, the flow channel of the Siegbahn portion and the flow channel of the thread groove pump portion are connected to each other. the length of a compression flow channel of the thread groove pump portion can be increased in a radial direction due to the connected Siegbahn portion.

In a vacuum pump, a spiral plate on a downstream side of a slit is not disposed on an extended line of a spiral plate on an upstream side of the slit but is disposed after in a direction in which a gap formed by the slit is reduced. The distance by which the downstream spiral plate is moved corresponds to the distance in which the gap disappears and the upstream spiral plate and the downstream spiral plate overlap. When scraping the spiral plates, the radius of a machining end mill is set smaller than the width of the slit of the spiral plate, and the radius of the machining end mill is set smaller than the phase difference between the upstream spiral plate and the downstream spiral plate. In addition, end portions of the spiral plates between which the slit is formed are subjected to chamfering.

A roadway or pavement sweeper with multiple sweeping modes for the removal of debris from a swept surface may, in some embodiments, include a sweeper vehicle having a pair of side-brooms independently movable between a retracted and extended position for sweeping debris into an area therebetween and at least one material-transfer broom to sweep a portion of the debris accumulated between the side-brooms as the vehicle moves in its direction of travel. A fan-driven suction-inlet may be provided at or adjacent each side of the vehicle. The at least one material-transfer broom may rotate in a first or other direction to transfer debris for entrainment into a selected suction-inlet for transfer to a debris hopper. Other embodiments are also described.

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 pump includes; a rotor, a stator, a motor, a heating section heating the pump base portion, a base temperature detection section detecting a temperature of the pump base portion, a rotor temperature detection section detecting a temperature equivalent as a physical amount equivalent to a temperature of the rotor, and a heating control section to control heating of the pump base portion by the heating section such that a detection value of the rotor temperature detection section falls within a predetermined target value range. A monitoring device comprises: an estimation section configured to estimate, based on multiple temperatures detected over time by the base temperature detection section, maintenance timing at which the temperature of the pump base portion reaches equal to or lower than a predetermined temperature; and an output section configured to output maintenance information based on the estimated maintenance timing.

An electric blower includes a motor unit, a shaft, a centrifugal impeller, a fan cover, a motor unit case, and a bracket located away from centrifugal impeller and toward motor unit in a direction in which a central axis of the shaft extends. The bracket includes a first portion located outward of the vent in a radial direction, and a second portion located outward of the first portion and outward of an outer circumference of the motor unit case in the radial direction. A first airflow passage and a second airflow passage are formed in the bracket, the first and second airflow passages communicate with an airflow passage formed by the centrifugal impeller and the fan cover.

In the turbo molecular pump, at least one of the multiple stages of the rotor blades and the multiple stages of the stator blades is configured to satisfy any one of a first condition of Xout<Xc and Xin<Xc, a second condition of .Math.XcXin>Xc>Xout where =1.04, or a third condition of Xin<Xc<Xout.Math.Xc where =1.04.

A screw disassembly device includes a driving mechanism, an electric screwdriver, and a collecting mechanism. The driving mechanism is coupled to the electric screwdriver to drive the electric screwdriver to move. The electric screwdriver disassembles a screw and includes a head portion. The head portion adsorbs the screw. The collecting mechanism includes a stripping member, a transfer block, and a receiving box. The transfer block is mounted on the driving mechanism. The transfer block defines a transfer chamber. The head portion movably passes through the transfer block and the transfer chamber. The stripping member clamps the screw within the transfer chamber to remove the screw from the head portion. An inner chamber of the receiving box is coupled to the transfer chamber by the transfer tube. The receiving box generates a negative pressure to suck the screw through the transfer tube into the receiving box.

A roadway or pavement sweeper with multiple sweeping modes for the removal of debris from a swept surface may, in some embodiments, include a sweeper vehicle having a pair of side-brooms independently movable between a retracted and extended position for sweeping debris into an area therebetween and at least one material-transfer broom to sweep a portion of the debris accumulated between the side-brooms as the vehicle moves in its direction of travel. A fan-driven suction-inlet may be provided at or adjacent each side of the vehicle. The at least one material-transfer broom may rotate in a first or other direction to transfer debris for entrainment into a selected suction-inlet for transfer to a debris hopper. Other embodiments are also described.

A portable air extracting device includes a shell assembly and an electric air extracting pump. The shell assembly includes a top shell, a side shell and a bottom shell surrounding a fluid room. The bottom shell is provided with an external air-extracting hole. The external air-extracting hole connects the fluid room to a target space to be evacuated. The electric air extracting pump includes an intake nozzle and an outtake nozzle. In particular, the intake nozzle is misaligned with the external air-extracting hole.