A pump with variable suction/discharge amount and a transmission drive device and a driving method thereof. The pump is a rotary vane pump having a vane chamber body. The vane chamber body is composed of a fixed wall member, a movable wall member, a movable vane chamber sleeve and a vane rotor. The vane chamber is extendable/retractable in an axial direction of the vane rotor. At least two pumps are assembled in communication with each other to form a closed loop for the active pump to drive the passive pump. In operation, passive the vane chambers of the active pump and the passive pump are automatically extended/retracted and modulated until the driving force and the load resistance achieve a balanced state passive, the vane chambers and the rotational speeds of the active pump and the passive pump are automatically adjusted to be in inverse proportion to each other.

A method is provided for controlling a temperature of a vacuum pump of a dry vacuum pump type subjected to variable pumping loads, the pump including a stator, a pumping stage, two shafts extending into the stage and respectively bearing a rotor to rotate synchronously in opposite directions in the stator and to drive a gas from a suction inlet to a delivery outlet, a cooling element coupled to the stator, a temperature sensor to measure a stator temperature, and a controller to control the stator temperature by the cooling element and the temperature sensor; and the method including controlling the pump temperature by the cooling element based on a temperature setpoint and a measurement of the stator temperature, and monitoring whether a value of a pumping load parameter is below a load threshold and, if so, increasing the setpoint. A vacuum pump and a system are also provided.

A load identification method for reciprocating machinery based on information entropy and envelope features of an axis trajectory of a piston rod. According to the present disclosure, firstly, the position of an axial center is calculated according to a triangle similarity theorem to obtain an axial center distribution; secondly, features are extracted from the axial center distribution of the piston rod by means of an improved envelope method for discrete points as well as an information entropy evaluation method; thirdly, a dimensionality reduction is carried out on the features by means of manifold learning to form a set of sensitive features of the load; and finally, a neural network is trained to obtain a load identification classifier to fulfill automatic identification on the operating load of the reciprocating machinery. The advantages of the present disclosure are verified by means of actual data of a piston rod of a reciprocating compressor.

A load identification method for reciprocating machinery based on information entropy and envelope features of an axis trajectory of a piston rod. According to the present disclosure, firstly, the position of an axial center is calculated according to a triangle similarity theorem to obtain an axial center distribution; secondly, features are extracted from the axial center distribution of the piston rod by means of an improved envelope method for discrete points as well as an information entropy evaluation method; thirdly, a dimensionality reduction is carried out on the features by means of manifold learning to form a set of sensitive features of the load; and finally, a neural network is trained to obtain a load identification classifier to fulfill automatic identification on the operating load of the reciprocating machinery. The advantages of the present disclosure are verified by means of actual data of a piston rod of a reciprocating compressor.

A method of operating a rolling piston compressor includes determining a pressure difference (?P) between a discharge pressure (P.sub.d) within a compression volume and a suction pressure (P.sub.s) within a suction volume; determining a pressure ratio (r.sub.p) equal to the discharge pressure (P.sub.d) over the suction pressure (P.sub.s); estimating a discharge pressure (P.sub.d) based at least in part on the pressure difference (?P) and the pressure ratio (r.sub.p); determining that the discharge pressure (P.sub.d) is greater than a predetermined pressure limit (P.sub.d-limit); and lowering a target speed (?.sub.target) of the rolling piston compressor.