Haskel 8 Serie Instructions De Fonctionnement Et D'entretien page 14

8" Drive Liquid Pumps • OM-LP-800F
6.4 Theory - Pump Sections
The pumping action on either end may be single acting or double acting. However, note that there are no
complete models that are single acting output since all models that have single acting ends assume that
the user will interconnect the ends to provide double acting output (or specify this option at time of order).
For further reference, study the schematic diagrams in Fig.1 and relate the applicable diagram to the
individual assembly drawing included with your pump.
6.5 Testing Pump Section
(USE THE SAME TEST SETUP DESCRIBED IN 6.3 ABOVE)
6.5.1 SINGLE ACTING PUMP SECTIONS
Full of liquid, either end should stall indefinitely on the output stroke. If not, leakage must be occurring at:
a.) the inlet check valve, and/or b.) the plunger seal. An inlet check problem is best found by removing its
parts and inspecting for trash or damage. A plunger seal leak is quickly detected at the vent hole
provided.
The outlet check valve is tested by stalling, then venting the air to the drive section. This "relaxes" the
liquid in the pump section. The outlet check should solidly trap pressure in the outlet line and gauge. If it
falls off, the problem is best found by removing its parts and inspecting for trash or damage.
6.5.2 DOUBLE ACTING PUMP SECTION
Use the same test setup as described in 6.3 above. Full of liquid, the unit should stall indefinitely on the
"pull" or "push" stroke. Inability to stall (creep and recycle) on the "pull" indicates internal leakage of either
(or both) the pump piston seal and or internal ball check, or external leakage of the plunger seal (evident
at vent hole). Each should be inspected for trash or damage as should also the pump barrel for scratches.
Creep and recycle on the "push" indicates fault at a.) The inlet check valve and/or b.) The plunger seal.
Recommended action is the same as a.) and b.) suggestions 6.5.1 above.
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