| 摘要 |
<p>A powder spray system (10) includes a powder pump with a body (16) having a passage (26) which receives pressurized air, mixes powder particles therein and conveys the mixture to a powder gun for spraying from the gun. The mixing of powder particles occurs via generation of a negative pressure region (30) within the passage. This negative pressure region (30) is created by a venturi (28), which is removably received in the body (16), and which has a bellmouth shape at both ends (50,52). By providing a bellmouth shape at each end (50,52) of the plastic venturi (28), the venturi (28) may be used during an initial period of powder coating, then removed, reversed and relocated in the body for a second period of coating. This minimizes the adverse affects of consumption or wearing away of the venturi (28) at the upstream end, a susceptibility of plastic venturis, and thereby doubles the useful life of the venturi. <IMAGE></p> |
