| 摘要 |
PURPOSE:To prevent accidents due to too much confidence upon a pressure gauge by indicating pressure by movement of a piston and by providing a safety valve on the least upper bound part. CONSTITUTION:The outside wall of a cylinder 2 is marked with degrees 7, and a needle 6 is bent at the position to read the position of a piston 4. A coil spring 9 is disposed, taking the upper seat portion 8 as a seat, and the piston 4 is pushed downward until it surpasses the pressure P of the cylinder. The upper portion of the cylinder 2 is provided with a safety valve jet hole 10, thereby to emit the internal pressure when the piston 4 goes upwards, passing by this position, so as to prevent accidents due to too much confidence upon a pressure gauge. |
