PURPOSE: To control both flows and allow two pipelines to be closed simultaneously by setting the voltage applied to a solenoid pilot valve in three ways, thereby controlling a first and a second valve bodies to act in three ways.
CONSTITUTION: When 100% voltage is applied to a pilot valve 20, a piston 23 is pulled up to communicate a high pressure conduit 25 with a first pressure conduit 7, and a low pressure conduit 26 with a second pressure conduit 8 respectively. As a result, the pressure of a first valve control chamber 13 becomes higher than that of pipelines 6, 8, 10, and a first communicating hole 4 is closed by the movement of a first valve 11. On the other hand, the pressure of a second valve control chamber 14 becomes lower than the pipelines 6, 8, 10, so that a second communicating hole 5 is opened by a second valve body 12. When current application to the pilot valve 20 is cut off, the piston 23 is pushed down by spring force, so that the pressure relation becomes the reverse of the above- mentioned case, and the communicating hole 4 is opened and the communicating hole 15 is closed. When the voltage applied to the pilot valve 20 is 50%, the piston 23 is fixed at an intermediate point, and the pressure of both first and second valve control chambers 13, 14 becomes high, and therefore both communicating holes 4, 5 are closed.
IIJIMA HITOSHI
TANAKA NAOKI
