Abstract: The constant quantity injection valve (1) comprises a valve housing (2), a first and a second valve (3, 4) respectively including valve pins (8, 9) and ring-like packings (10, 11), and a measuring chamber (5) formed in the valve housing between the two valves. The valve housing has a gas blow-out passage extending along its axis. The individual valves are located on the upstream and downstream sides (7a, 7b) of the blow-out passage, and the valve pins are axially movable and respectively include closing sections (12, 13), opening sections (14, 15) and inclined sections (16, 17) connecting the two sections. The ring-like packings are made of an elastic material with a rubber hardness of 90.degree. or above, the three sections of each of the valve pins being detachably mounted on the peripheral wall of the blow-out passage.

Abstract: The gas supply mechanism with a safety device of the present invention uses a small size high pressure gas container. In connection with a gas passage, a safety device is installed, which allows the gas in the passage to flow out gradually when the gas pressure in the passage rises excessively. A gas discharge port of this safety device is open on the same surface as the surface of the main body and does not protrude from the body.

Abstract: A portable torch including: a gas tank containing therein a combustible gas and another gas tank containing therein a combustion supporting gas; a plurality of pressure regulating mechanisms, in which the primary pressure sides are connected to said gas tanks through plug opening mechanisms, respectively; and a torch portion is connected to the secondary pressure sides of the pressure regulating mechanisms through flexible gas feeding tubes, respectively, provided at the forward end thereof with a jet and having no gas flow rate regulating function. The pressure regulating mechanisms regulate the secondary pressure and gas flow rate from the jet through the secondary pressure. Check valves for blocking the flow of gas from the torch portion to the pressure regulating mechanisms is interposed between the respective pressure regulating mechanisms and the torch portion, to thereby prevent backfire of the flame of the jet.

Abstract: The gas supply mechanism includes a main body, a nut, a packing having an O-ring part and a ringlike flange part, a piercing body and a valve housing. The O-ring part fits well the sealing cover of a gas cartridge even if the surface of the sealing cover is not flat. The valve housing has a gas passage and a bypass which enables to prevent pulsation of gas flow.