| 摘要 |
<p>A pump (110) including a housing having an inlet (112) and an outlet (114) with a respective one way inlet valve (122) configured to allow flow of fluid into the housing and one way outlet valve (124) configured to allow flow of fluid out of the housing, a pumping arrangement (115) having a piston member (120) positioned in the housing and a drive member (135), the drive member (135) extending through a drive member opening (133) in the housing and being operable to cause axial movement of the piston member (120) in first and second opposite directions, a piston seal (130) extending between the piston member (120) and the housing so as to separate a volume within the housing into a first chamber (116) defining a first volume at one side of the piston member (120) and a second chamber (118) defining a second volume at the other side of the piston member (120) and being in fluid communication with the drive member opening (133), the piston member (120) having a piston valve (140) allowing flow of fluid from the first chamber (116) to the second chamber (118), such that movement of the piston member (120) in the first direction causes the first volume to increase and the second volume to decrease thereby causing fluid to flow into the first chamber (116) through the inlet valve (122) and causing fluid to flow from the second chamber (118) through the outlet valve (124), and such that movement of the piston member in the second direction causes the first volume to decrease, thereby causing fluid to flow from the first chamber (116) into the second chamber (118) through the piston valve (140), and a drive member seal (132) through which the drive member (135) extends, that inhibits flow of fluid from the second chamber (118) through the drive member opening (133) in the housing.</p> |
