| 摘要 |
A quick color change powder coating system has a powder supply, a powder pump that receives powder from the powder supply through a suction pick-up tube, a spray gun and a powder hose that connects the pump to the gun. The apparatus includes a purge air switch assembly and a first air source that provides air at purge pressure to a first inlet of the purge air switch assembly. A second air source provides flow rate air to a first pump inlet and atomizing air to a second inlet of the pump via a purge air switch assembly. Powder is drawn up the tube and into the pump by suction produced by flow rate air into the pump. A purge inlet is associated with the powder inlet to the pump. The purge air switch assembly operates in response to a purge control signal to connect purge air to the atomizing inlet at the pump and to the pump's purge inlet; whereby the pump, hose and gun can be purged at the same time. Purge air may also be provided between the pump and hose and between the hose and the gun to further increase purging efficiency. A powder hose cleaning device is also provided which includes a wiper device such as an annular seal that closely fits about the tube exterior. As the tube is, withdrawn, the wiper device knocks powder off the tube exterior back into the hopper to reduce clean up time and waste of powder. |
