Conformal coating applicator and method

摘要

An applicator (10) for dispensing a liquid conformal coating material onto a substrate. The applicator (10) includes a body assembly (12) with a liquid flow passage (40) having a liquid inlet (16) adapted to receive the coating material and a liquid outlet (44). A valve seat (62) is positioned between the liquid flow passage (40) and the liquid outlet (44). A valve stem (70) is mounted in the body assembly (12) for reciprocating movement between an open position and a closed position. The valve stem (70) includes a first end (70a) and a second end (70b). The first end (70a) of the valve stem (70) engages the valve seat (62) in the closed position to stop flow of the liquid coating material through the outlet (44) and disengages from the valve seat (62) in the open position to allow flow of the liquid coating material through the outlet (44). A valve actuating mechanism is operative to move the valve stem (70) from the open position to the closed position and is further operative to move the valve stem (70) from the closed position to the open position. A resilient dampening element (180) is operatively coupled between part of the body assembly (12) and the valve stem (70). The resilient dampening element (180) provides a biasing force against the valve stem (70) as the valve stem (70) moves from the closed position to the open position to reduce rebounding movement of the valve stem (70) toward the closed position.