How does adjusting the vacuum control the velocity?
The goal is to maintain a constant velocity at a constant pump speed. Select a velocity that you wish to maintain, say 14 feet per second (fps). If the velocity is faster than 14 fps, increase the vacuum setting to take in solids at a greater rate. The velocity will slow as the load of solids in the system increases. If the velocity slows to a rate below 14 fps, decrease the vacuum setting to take in solids at a slightly lower rate or enough to cause the velocity to slowly increase. Experience will tell the operator how much to increase or decrease the vacuum to keep the velocity constant. The CONVAC system touch pad enables the vacuum to be adjusted in one tenth of an inch of vacuum increments. With a little practice, adjustment may be required only every few minutes.
