Haskel 8 Serie Instructions De Fonctionnement Et D'entretien page 11

8" Drive Liquid Pumps • OM-LP-800F
5.6.6 Refer to assembly drawing for special notes including torque required for tie rod nuts on some
models.
5.7 Pump Section Pistons and Plungers
The -40 and -65 models are the only two that use a packed piston. All other models use a packed
plunger.
5.7.1 The packed piston in the -40 and -65 models seals on the "pull" stroke only providing output flow
while at the same time providing inlet suction. The ball type check valve is installed inside the piston to
provide free flow through the piston on the "push" stroke. The assembly drawing provides construction
detail. Note that the threaded in seat is sealed with Loctite CV (Blue). Maintenance is rarely required but if
disassembly is necessary, moderate heat with a heat gun is suggested to soften the Loctite. (Ref. 5.1 for
reassembly)
5.7.2 Piston seals. Refer to the assembly drawing. As you can see, the piston and rod can be removed
from the barrel after removal of the inlet port end cap and the cross pin through the rod on the opposite
end.
NOTE: The 52183 round retaining ring cannot be put in, or pried out of its groove with the 52199 split
bearing in place. Therefore this split bearing is first out and last in.
5.7.3 Plunger seals. Refer to the assembly drawing detail. Note that all plunger seals are provided with a
leak passage terminating in a 1/8" NPT drain port. Use this port to monitor the start of seal failure.
Therefore it is recommended that it be left open (not connected to liquid source). Disassembly and
reassembly should be self evident. Particular care should be taken during reassembly to not scratch any
of the parts as they are being seated into place.
5.7.4 Always inspect the polished surface of the plunger O.D. (all models) and barrel I.D. (-40 and -65
models only) for scratches. Many can be polished out with #600 emery paper. If scratch remains, the part
will probably require replacement if full performance is expected.
5.7.5 The remainder of disassembly and reassembly depends upon the parts makeup shown on your
particular assembly drawing. The extent of disassembly should be determined by the initial reasons for
disassembly; that is end cap seal leakage, piston seal leakage, or rod seal leakage. O-rings, seals and
backup rings are the most likely parts requiring replacement and are coded for kit replacement.
5.7.6 Clean all parts (Ref. paragraph 5.1) and inspect for nicked, grooved, scratched or scored wear
surfaces.
5.7.7 Replace all parts that are damaged. Static o-rings, although usually included in seal kits can often
be reused in emergencies without problem.
NOTE: Avoid lubricating any pump section bearings, seals, o-rings, backup rings, plungers or inner
surface of barrels. These parts are designed to be self-lubricating.
5.7.8 Reassemble parts in reverse order of disassembly. Refer to assembly instructions on assembly
drawing for final details.
5.7.9 Alternately (crosswise) torque tie rods nuts to maximum torque value per assembly drawing notes.
6. Functional Operation and Theory
6.1 Purpose
To understand the principles of both drive and liquid sections as an aid to proper application, installation
and trouble shooting.
6.2 Theory- Drive Section
The drive section is a "Linear" air motor which will continuously reciprocate when the drive air (or gas) is
applied to its 3/4" NPT inlet while exhaust is freely permitted from its dual 1 -1/4" NPT exhaust ports. The
drive piston is alternately powered and exhausted on its opposite sides by the 4-way, 2-position spool
valve to provide a power stroke in both directions ("push" and "pull").
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