Abstract: A pipe line for fluid to be detected is formed so that heat from a flow rate detector in which a thin-film heating element and a thin-film temperature sensing element are laminated on a first surface of a substrate through an insulating layer is transferred to and absorbed by the fluid. In the flow rate detector, the temperature sensing which is affected by the heat absorption of the fluid due to the heating of the thin-film heating element is executed by the thin-film temperature sensing element, and the flow rate of the fluid in the pipe line is detected on the basis of the temperature sensing result. A fin plate extending into the pipe line is joined to a second surface of the substrate of the flow rate detector by a joint member, and the fin plate extends so as to pass through the central portion on the circular section of the pipe line. The dimension of the fin plate in the direction of the pipe line is larger than the dimension L2 of the thickness.

Abstract: A helium gas compressing apparatus constructed in such as manner that: an oil separator in a high-pressure gas passage is connected to a low-pressure gas passage; and oil return path having first and second branch paths is provided between the high- and low-pressure gas passages; a capillary tube is installed in one of the two branch paths; and an adjustment valve is installed in the other branch path to adjust the pressure difference between the supply gas in the high-pressure gas passage and the return gas in the low-pressure gas passage. Because of this construction, the adjustment valve can be manipulated from outside to make fine adjustments on the pressure difference or change it to a desired value with ease even during operation of the apparatus, thereby adjusting the refrigerating capability of a helium refrigerating machine connected to the apparatus and the power consumption of the helium gas compressing apparatus.

Abstract: A multistage discharge type rotary vacuum pump comprises a rotor rotably mounted within a cylinder chamber and dividing the cylinder chamber into first stage and second stage working chambers. A plurality of radially extending vanes are slidably mounted in the rotor in angularly spaced relation, and the vanes undergo radial sliding movement during rotation of the rotor such that the vane tips maintain sliding contact with the cylinder chamber. Each working chamber has an inlet port at the upstream side thereof for admitting exhaust gas evacuated from a confined space during use of the pump, and an outlet port at the downstream side thereof for discharging the exhaust gas which has been compressed in the working chamber in response to rotation of the rotor. The outlet port of the first stage working chamber communicates through a discharge valve with a storage chamber, and the storage chamber communicates through a pressure-responsive discharge valve with the inlet port of the second stage working chamber.

Abstract: A refrigerator comprising a piston which is driven in a reciprocating fashion within a cylinder by the difference in pressure of working gas alternately supplied to first and second variable-volume chambers separated by said piston, a motor, a rotary valve which is attached to an output shaft of said motor and which switches a passageway for said working gas provided between said first and second variable-volume chambers alternately to a high-pressure supply side and low-pressure return side, and at the same time blocks said passageway, and a cam which is mounted on an output shaft of said motor and which guides the reciprocation of said piston in accordance with the motion of said rotary valve connected to said piston rod.