Abstract: A regenerative type engine which improves efficiency is provided. The regenerative type engine with fluid control mechanism comprises a radiator arranged in a position which is at least one of between the pressure fluctuation source and a regenerator and between a cold head and a phase regulating mechanism, and a flow path controller connected to the radiator, for independently regulating the flow path in the forward process and the flow path in the backward process of the operating fluid within the system of the regenerative type engine, the flow path controller independently regulating the flow path in the forward process and the flow path in the backward process such that the flow path in the forward process passes through the radiator and the flow path in the backward process bypasses the radiator.

Abstract: A pulse tube refrigerator includes a compression space defined by a compression piston inside a cylinder, an expansion space defined by an expansion piston inside a cylinder, the expansion piston being reciprocated at an advance angle of a constant phase difference within a range of 10.degree.-45.degree. relative to the compression piston, and first and second thermal systems communicating the compression and expansion spaces. Each thermal system has a radiator, a regenerator, a cold head and a pulse tube, with the regenerator of the second thermal system being composed of two regenerator sections. The cold head of the first thermal system is made to perform a heat exchange with the second thermal system between the two regenerator sections thereof, whereby a very low temperature is obtained from the cold head of the second thermal system.

Abstract: A pulse tube refrigerating system comprising a compressing cavity for compressing a working fluid, a heat radiator connected with the compressing cavity and a regenerator connected with the heat radiator. A pulse tube is provided and connected with the heat radiator through a refrigerating section. The pulse tube is connected through a heat exchanger and a flow regulating valve with an expansion cavity which is operable with a phase difference with respect to the compressing cavity, whereby the working fluid from the compressing cavity is cooled by the heat radiator and passed through the refrigerating section into the pulse tube, the working fluid in the pulse tube being compressed by the working fluid from the refrigerating section to be increased in temperature and passed to the heat exchanger to radiate heat.