3–600 Page 9
FIGURE 4 – CUP TYPE PISTON
Temperature
Pressure
Texture
–20
_
F to 212
_
F
0 to 125 PSI
Soft
(–28.9
_
C to 100
_
C)
(0 to 8.79 kg/cm2)
–20
_
F to 300
_
F
100 to 500 PSI
Medium
(–28.9
_
C to 148.9
_
C) (7.03 to 35.15 kg/cm)
30
_
F to 300
_
F
500 to 1000 PSI
Hard
(–1.1
_
C to 148.9
_
C) (35.15 to 50.31 kg/cm)
FIGURE 5 – PISTON TEXTURES
2.
Fit cup snugly to the hub.
3.
Mount the spacing plate.
4.
Mount the outer cup.
5.
Mount the follower plate and tighten the nut and
locknut securely.
For the texture of the cups, see FIGURE 5.
Clean Oil or Petroleum Products Service (All Pres-
sures) – Solid metal pistons with grooves and metal
snap rings or non–metallic rings with expanders are
recommended. Piston ring grooves have the proper
clearance but it is necessary to check rings for end
clearance. Insert each ring in the cylinder liner and
check end clearance with a feeler gauge. Metal rings
should have from .003” (.076 mm) to .004” (.1 02 mm)
per inch (25.4 mm) of ring diameter and nonmetallic
should have from .006” (.152 mm) to .008” (.203 mm)
per inch (25.4 mm) of ring diameter.
High Pressure Pistons For Abrasive Service – For
high pressure slush service or mud with abrasive par-
ticles, a regular oil field rubber type piston is recom-
mended.
High Temperature Service – Consult the Factory for
recommendations.
Fluid Piston Rod Packing – Braided synthetic pack-
ing is standard for water, oil and general service. Maxi-
mum service ratings for this packing are 250 PSI and
250
_
F.
Molded convex packing is standard for mud service.
Maximum rated service temperature is 180
_
F.
Molded rubber and duck packing is standard for grout
and cement service and optional for other services.
Maximum rated service temperature is 250
_
F.
Rod packings should always be installed in a clean
stuffing box. Each ring should be firmly seated by tamp-
ing as it is applied. When box is full, gland nuts should
be tightened with a wrench just enough to seat the
packing properly; then slacken off and tighten nuts by
hand, locking the gland with a final quarter turn with a
wrench. DO NOT TIGHTEN GLANDS TOO TIGHT.
Some fluids require special packing and should be re-
ferred to the factory.
Fluid Piston Rod Baffle – All pumps are supplied with
an oil resistant rubber baffle which is mounted on the
piston rod between the piston rod stuffing box and the
oil stop head. The baffle must be kept in place to pre-
vent foreign material following along the piston rod from
the stuffing box into the power end.
Warranty is void if this baffle is not in
place.
Frame Oil Stop Head Packing – Oil stop head pack-
ing is cut square fibrous rings. The packing should be
inspected frequently and adjusted if necessary. Re-
place when worn.
Fluid Cylinder Liner Packing – Current liner packing
construction consists of two ”square rubber hydraulic
rings” with a metal spacer between them and is suitable
for most services.
