| 摘要 |
<p>A plural component dispensing system includes supplies which furnish first and second components, such as a resin and catalyst, under pressure to a hand-held dispensing device having first and second valves, respectively. First and second passageways lead from the first and second valves to a mixing chamber in which the components are mixed, and from which the components are ejected. Upon mixing, the components are subject to increasing viscosity and hardening. A third valve controls flow of a purging medium from a supply of such a medium to the mixing chamber. A sensing device, such as a pressure sensor, senses the orientation of either/or both of the first and second valves. When the first and second valves are moved to positions to halt the flow of the two components, the sensing device generates a signal to start a first timing device. At the end of a predetermined time interval, the first timing device generates a signal which opens the third valve, permitting the purging medium to flow into the chamber and purge the mixed components from the chamber before they harden, The first timer also starts a second timer. At the end of a second predetermined time interval, the second timer generates a signal which closes the third valve, halting the flow of the purging medium.</p> |
