Milton Roy PRIMEROYAL Instruction Manual page 7

Figure 2
Piping should be sloped to prevent vapor pockets, because vapor in the liquid end will
cause inaccurate pump delivery.
When pumping suspended solids (such as slurries), install plugged crosses at all 90 degree
line turns to permit line cleaning without dismantling piping.
Suction Piping
It is preferable to have the suction of the pump flooded by locating the liquid end below the
lowest level of the liquid in the supply tank. Installing a hold-up tower or supply vessel on the
suction line close to the pump can help ensure a flooded suction line. (Consult the Milton Roy
Company, Flow Control Division for assistance in such applications.)
Avoid negative suction pressure conditions (suction lift), as such conditions adversely affect
metering accuracy. If such conditions are unavoidable, contact Milton Roy Flow Control
Division for recommendations.
When pumping a liquid near its boiling point, provide enough suction head to prevent the
liquid from "flashing" into vapor when it enters the pump liquid end on the suction stroke.
If possible, use metal or plastic tubing for the suction line because tubing has a smooth
inner surface and can be formed into long, sweeping bends to minimize frictional flow losses.
A strainer should be used in the suction line to prevent foreign particles from entering the
liquid end. This and any other measures which prevent debris from entering and fouling the
ball-checks will give increased maintenance-free service.
Keep suction piping as short and straight as possible.
When suction piping is long, and particularly at stroke speeds above 70 strokes per minute (spm),
piping size should be larger than the liquid end suction fitting to prevent pump starvation.
If long suction lines are unavoidable, install a float box or auxiliary feed tank (stand pipe) near the
suction side of the pump. The float box may be calibrated and used to check pump capacity by
measuring the time required for pumping a specific quantity of liquid from the box. In many cases,
installing an accumulator or pulsation dampener at the pump suction connection will promote
flooded suction even when the suction line is long. Consult Milton Roy Flow Control Division for
details.
6