Title: Actuator or VSD Flow control for metering pumps

There is controversy relative to the selection of actuators or variable speed drives for flow control of diaphragm metering pumps. This article comes down in favor of the VSD. A metering pump’s capacity is a function of the diameter of the plunger, the effective length of the stroke and the rate or speed of stroking. Since the diameter of the plunger must remain constant in any given pump, varying the stroke length and pump speed are the only ways to adjust flow. As automation gained in popularity, pneumatic and electronic actuators were attached to the stroke adjustment mechanism for both amplitude, modulated and lost motion metering pumps. Although they provide a level of convenience, the slow rate of change (typically 1 second/1% of stroke length) results in pumping inaccuracies during the adjustments. The advantages of the actuator approach are greater accuracy. One advantage is that AC and DC drives can respond more quickly, with approximate speeds of 0 to maximum RPM in 0.5 and 1.3 seconds, respectively. Faster flow correction results in greater long-term accuracy.

Click Here For Complete Article Text


   Person Information
   Application Sequencing
Company  Product  Process  Other  Subjects  Event  Event  Date  Location  Publication  Publication  Date Text  Descriptor
  • Actuator

  • Control

  • Metering

  • VSD







  • Article