| 摘要 |
PROBLEM TO BE SOLVED: To prevent plunger's abrasion caused by mineral particles which are assumed to leak, and enlarge life of a packing device. SOLUTION: In packing elements 29, 31 inserted into a sliding portion between a plunger 8 and a cylinder, a vector of a liquid pressure P acting to any point on the outer surface of a part near a sliding portion directs outside in relation to the central line of the plunger. When the vector directs inside, an angle made between a surface orthogonal to the axis and the vector is larger than 60 deg.. High pressure fluid in a pump chamber infiltrates through between a plunger surface and the packing element 29 and therefore leaks in principle, but mineral particles such as cement particles contained in the fluid between them do not scratch the plunger surface. |
