| 摘要 |
<p>PURPOSE:To form a low pressure drain passage in which pressure is equal to atmo spheric pressure by forming a circular groove on a second abutting surface of a valve block on the outer side position of each port, and opening a drain joining passage communicated therewith to a first abutting surface and the second abutting surface of the valve block. CONSTITUTION:A circular groove 40 is formed for instal.ling an O-ring which seals a valve block abutting surface on the outer side of a second abutting surface 10b, which groove is opened to a first abutting surface 10a and the second abutting surface 10b of a valve block 10. An O-ring 41 is installed in the circular groove 40 on the side of an outer peripheral edge 40a. A circular drain passage 42 is formed between an inner peripheral edge 40b and the O-ring 41 independently on first and second tank ports 19, 20, and opened to the first abutting surface 10a at a drain joining passage 43. The plural first abutting surfaces 10a and the second abutting surfaces are in contact brought into connection with each other. The drain passages 42 are communicated with a each other, while are not communicated with the respective first and second tank ports 19, 20. Thus, they are independently communicated with the tank. The pressure inside the drain passages 42 is substantially equal to atmospheric pressure.</p> |
