Self-powering three-way change valve

The invention discloses a self-operated three-way reversal valve. The reversal valve comprises a valve body, and a first piston, a second piston, a sliding guide and a sliding block which are arranged in the valve body, and a spring. A valve seat, an adaptor tube C, an adaptor tube E and an adaptor tube D which are arranged on the valve body form a receiving cavity together with a low-pressure capillary tube and a high-pressure capillary tube. The sliding block is arranged on the valve seat. The sliding guide is fixed with the sliding block. The sliding guide is connected with the first piston and the second piston to form a piston and sliding guide assembly which can move axially in the valve body. The spring is arranged between the second piston and a left end cap. The sliding block is provided with a radially limiting structure in the valve body. The radially limiting structure is as follows: the sliding block comprises a transverse structure and a vertical structure arranged above the transverse structure; and the bottom of the transverse structure is closely attached to the valve seat; a top surface of the vertical structure of the sliding block has a longitudinal groove; and top surfaces of twp convex parts of a convex shape of the groove are closely attached an inner wall of the valve body. The structure of the valve can improve heat tube circulation refrigeration efficiency and is high in efficiency and energy-saving.