Abstract: The present application provides a slide valve, wherein the slide valve is configured to regulate a load of a twin-screw compressor. The slide valve comprises a slide valve body, wherein the slide valve body has a connecting end and a free end, the connecting end is configured to connect to a slide valve connecting rod of the twin-screw compressor, and the slide valve is driven to slide by the slide valve connecting rod. A cavity is formed in the free end of the slide valve body, and the slide valve has a passage configured to fluidly couple the cavity with an external fluid to reduce air flow pulsations on a suction side of the twin-screw compressor and thereby reduce overall air flow pulsations in the twin-screw compressor.

Abstract: The present application provides a screw compressor that comprises a first male rotor and a second male rotor, each of the first male rotor and the second male rotor having convex-helical teeth, the first male rotor and the second male rotor being rigidly connected together; a first female rotor and a second female rotor, each of the first female rotor and the second female rotor having concave-helical teeth, the first female rotor being arranged separately from and opposite to each other; wherein the convex-helical teeth of the first male rotor are engaged with the concave-helical teeth of the first female rotor, and the convex-helical teeth of the second male rotor are engaged with the concave-helical teeth of the second female rotor. The male rotors in the screw compressor are symmetrically so that the axial force exerted on the first male rotor counteract with the axial force exerted on the second male rotor.

Abstract: The present disclosure relates to an oil flow switch, comprising a float device connected to a circulating oil passage and a floating liquid level switch element provided in the float device, wherein the float device comprises an oil inlet, an oil outlet, and a float chamber provided between the oil inlet and the oil outlet, the floating liquid level switch element is provided in the float chamber, and the float device is provided with a channel in communication with the float chamber. The oil flow switch according to the present disclosure may avoid a false alarm of the oil level switch and meanwhile mitigate disturbance to the float caused by liquid level fluctuation to reduce friction between the float and the sleeve rod. Further, a lubrication system with the above oil.

Abstract: A screw compressor is provided having adjustable internal volume ratio, including a body and a male rotor, a female rotor and a slide valve configured inside the body, a groove being configured at one side of the male rotor and the female rotor, and the slide valve being configured inside the groove with the slide valve movable inside the groove from a first position corresponding to a minimum internal volume ratio to a second position corresponding to a maximum internal volume ratio.

Abstract: An over-current protection method and circuit for a DC Inverter is provided in the present invention. Said over-current protection circuit comprises: a sampling unit for sampling output currents from a power module to form a sampling signal; a signal-processing unit for amplifying with various magnification factors and low-pass filtering the sampling signal to generate a first over-current signal and a second over-current signal; a signal-generating unit for generating a first interrupt trigger signal based on the first over-current signal; a comparison unit for comparing the second over-current signal with a reference voltage corresponding to an over-current threshold of a motor, with a comparison result being a second interrupt trigger signal; and a control unit for controlling the power module based on the first interrupt trigger signal, and the motor based on the second interrupt trigger signal.