| 摘要 |
PURPOSE:To settle the inner pressure quickly upon abrupt boost thereof by arranging a pair of openings for communicating the compression chamber at the innermost circumferential side with the gap at the back face of an element. CONSTITUTION:When the liquid is compressed and immediately before compression chambers 81, 82 at the innermost circumferential side are communicated with a delivery chamber 70, the inner pressure is at the highest level. A pair of openings 601a, 601b are provided such that the compression chambers 81, 82 at the innermost circumferential side are communicated with a gap 501 at the back face of an element 6. Consequently, the pressure in the gap section 501 is uniformed within the maximum level thus preventing collapse of the element 6. Since the pair of openings 601a, 601b are opened respectively to a pair of symmetrical compression chambers 81, 82, the pressure level is identical at all times and no pressure leak between them. |
