| 摘要 |
PURPOSE:To simplify the structure considerably while to increase the effective valve function of a pressure balance valve, by performing opening/closing of pressure balance valve and sliding of a pressure balancing sleeve through the piston itself. CONSTITUTION:At the final stage where a piston 3 will move in the arrow X direction in a cylinder 2 of the first stage pump 1, a stopper chip 15 provided on the head of the piston 3 will contact against a pressure balance first sleeve 10 and a ball valve 13 to open the valve port 12 thus to close a suction valve 6 and to block the gas compressed by the piston 3 from returning to the suction chamber 8. Simultaneously with opening of the valve port 12, pressure in the delivery chamber 9 will enter into the cylinder 2 to bring the pressure delivery chamber 9 near to balance. Consequently, the pressure of gas in the cylinder 2 will increase sufficiently to open the delivery valve 7 and to compress the gas into the delivery chamber 9, resulting in considerable simplification of the structure. |
