| 摘要 |
A fluid-driven reciprocating pump comprises a pair of pumping heads each containing a displaceable member defining a driving chamber and a pumping chamber, a mechanical connection coupling the two displaceable members for reciprocation together, and means for connecting the driving chamber of one pumping head to a source of pressurized fluid and the pumping chamber of that pumping head to a source of material to be pumped. The pump further includes means for connecting the driving chamber of the other pumping head to a source of pressurized fluid and for selectively connecting the pumping chamber of the other pumping head either to a source of material to be pumped to produce a double-action pumping operation wherein the material is pumped during both reciprocations of the displaceable members, or to the source of pressurized fluid to produce a single-action pumping operation wherein the material is pumped during only one of the two reciprocations of the displaceable members. |
