| 摘要 |
PURPOSE:To stop pressure reducing operation when entrance side pressure exceeds a set value, and hold exit side pressure as high as the entrance side pressure by providing an intake valve which opens a back pressure intake passage when the pressure in an inflow passage exceeds the set value to the back pressure intake valve. CONSTITUTION:When pressure higher than the set value set with a compression spring 31 for releasing is applied to the inflow passage 14 of a pressure reducing valve 10, an intake piston 30 is pressed down and the back pressure intake valve 37 leaves a back pressure intake valve seat. Consequently, the pressure in the inflow passage 14 is guided to the back pressure chamber 27 behind the differential piston 13 to rough a valve chamber 19, valve seat 36, intake cylinder chamber 28, and passage 29. Consequently, the area ratio to pressure operating on the differential piston 13 vertically becomes almost 1:1 and both pressures Pi and Po are balanced on the basis of the area ratio. Therefore, pressure reducing operation is stopped and the pressure Po in an outflow passage 15 rises as the pressure Pi in the inflow passage 14 rises. |
