| 摘要 |
<p>Two materials, especially ones which react together, are applied by means of a spraying device 26. Each material is supplied from its own tank 48, 50 via a three-way valve 25, 26 to a mixer upstream of the sprayer. To avoid wastage when the spray-gun trigger is released, the valves 25, 26 are automatically switched to positions where each material is recirculated to its respective reservoir. The returned materials flow through back-pressure valves 47, 49 which may be adjusted so that the pressure drop in each fluid line is the same during recirculation as it is when spraying. This gives "steady-state" conditions throughout spraying.</p> |
