| 摘要 |
A plunger pump arrangement 30 includes a chamber 32 with an inlet 34 and outlet 36. Inlet and outlet valves 38, 40 are automatically (i.e. passively) actuated by a pressure differential thereacross. A main plunger 42 and a primer plunger 44 are selectively moveable into the chamber 32. The arrangement 30 is configured such that at the beginning of a pumping stroke the primer plunger 44 moves into the chamber prior to the main plunger 42, and at the beginning of a supply stroke the primer plunger 44 moves outwardly from the chamber 32 prior to the main plunger 42 moving outwardly. This reduces sudden changes in flow rate, especially as valves are opening and closing, resulting in quieter and more reliable performance with lower wear. The invention may be used for pumping thickened sludge. |
