| 摘要 |
A fluid dosing cartridge (110) comprising a fluid reservoir (112), a delivery conduit (114) with an output nozzle (22), a nozzle socket (24), a pump chamber (42) and plunger (44), and a check valve assembly (118). The check valve assembly (118) comprises a valve housing (26), defining a valve chamber (32), and first (34), second (36) and third (38) valve ports, and first and second check valves (28, 30). Each check valve (28, 30) comprises a stainless steel ball (46) resiliently biased under the action of a spring (50) and a valve seat (48). The valve seat (48) comprises a body member (52) and a circular wall member (56) defining a valve aperture (54). The valve seat (48) is formed from an ethylene based octene polymer material to give the valve seat (48) a degree of material compliance, such that the sealing section (56a) of the wall member (56) deforms under contact with the resiliently biased stainless steel ball (46), to thereby improve the seal closure between the valve seat (48) and the stainless steel ball (46).
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