| 摘要 |
<p>PURPOSE:To prolong the life of a first seal member by disposing a first and a second seal members respectively on the high pressure side and low pressure side of the shaft seal part of a plunger, and inserting an intermediate member, provided with an end connection for leading liquid leaking from the first seal member out into a liquid sump part, fixedly between both first and second seal members. CONSTITUTION:In the shaft seal part of a plunger 12 in a diaphragm pump, a first seal member 28 provided on the high pressure side and a second seal member 30 provided on the low pressure side are respectively disposed in the axial direction, and a cylindrical intermediate member 32 is fixedly inserted between the first and second seal members 28, 30. A slight clearance 34 is provided between the inner periphery of the intermediate member 32 and the plunger 12, and the intermediate member 32 is pierced with a liquid through hole 36 formed radially. An end connection 38 formed at a housing 24 so as to be communicated with this liquid through hole 36 is connected to a liquid sump part through a pipeline 40. The restriction of leak quantity from the first seal member 28 is thereby eased to enlarge the abrasion allowed quantity of the first seal member 28, resulting in prolonging its life.</p> |
