Pulsafeeder Pulsa GLM DM7 - Manual (Page 8)

8
5.4 Discharge Pressure Requirements
All GLM ® DM7 metering pumps are designed for continuous service at the rated
discharge pressure. If system suction pressure exceeds discharge pressure (a
condition sometimes described as “pumping downhill”), flow would be generated
(siphoning) in addition to that caused by the pump. This results in a reduction in
accuracy and loss of control over the metering process. To prevent this flow-through
condition, the discharge pressure must exceed suction pressure by at least 0.35 Bar (5
psi). This can be achieved where necessary by the installation of a backpressure valve
in the discharge line. Conditions where the actual discharge pressure exceeds the
pump’s rating are to be avoided as they will cause damage to the pump components.
Figure 3, sample system configuration