Page 97 - Parker - Heavy Duty Hydraulic Cylinders

Catalog HY08-1114-4/NA Heavy Duty Hydraulic Cylinders
Exclusive Hi Load Piston Series 2H / 3H Custom Modifications

The Exclusive Parker
Hi Load Piston

The effective difference... Comparative Piston Seal Friction
Parker’s bronze-filled PTFE ring design.
PISTON SEAL FRICTION
The Hi Load piston assembly is comprised of two 2 IN. BORE
square-cut bronze-filled PTFE piston rings (A) with Nitrile
rubber expanders underneath (B) and two non-metallic 200
wear rings (C) which uniquely work together, incorpo- CAST IRON RINGS
rating the best qualities of both elements to achieve
dramatic efficiency. 175

150
(C) Fabric bearings (A) Bronze-filled PTFE seals

125
FRICTION...LBS.

(B) Nitrile rubber expanders 100

Reduced scoring. Low friction. The non-metallic wear 75 LIPSEAL WITH LEATHER BACK-UP
rings eliminate all metal-to-metal contact between the
piston and cylinder body. Some scoring may occur even
with the use of compatible materials such as cast iron or 50 BRONZE-FILLED PTFE
bronze for the piston and steel for the cylinder body.
The combination of the high imbeddability factor and D
the wiping action of the wear rings prevent contamina- 25
tion from getting between the piston bearing and sealing
surfaces, therefore, scoring is greatly reduced. This also
contributes to the extended life of the bronze-filled PTFE
rings. Other benefits of the Hi Load piston are excellent 0 500 1000 1500 2000 2500 3000
lubricity and minimum wear when using water-based PRESSURE...PSIG
fluids, soluble oil and water and biodegradable fluids.
Extensive controlled contamination tests in our labor-
atory have shown the Hi Load piston to operate more Virtually zero leakage. The Hi Load piston assembly
than 4 times longer than lip seals when high degrees of means virtually zero leakage with hydraulic and/or
contamination are present. water base fluids because of the continuous bronze-
filled PTFE rings with a homogenous inner ring of
Note: Because the Hi Load piston prevents metal-to- Nitrile rubber to apply seal preloading. The Nitrile
metal contact with the cylinder bore, steel pistons may expanders provide enough initial radial force to elimi-
be used which are stronger than other types. nate low pressure leakage. At higher pressure (above
Higher side load carrying capacity. Under severe side 2,000 psi) the seals are pressurized underneath, and
load conditions such as long stroke or pivot mounted are therefore dynamically self-sealing just as cast iron
cylinders the characteristics of non-metallic wear rings rings are.
provides increased side load carrying capability, which The bronze-filled PTFE resists extrusion in the clear-
is another distinctive benefit. Non-metallic bearings can ance between the piston much better than Nitrile, and,
also absorb shock, and with increased side load can as a result, provides at least double the life, increasing
give and thus conform more to piston and cylinder body. life spans as pressure goes up.
The action of deformation increases the area of contact,
which in turn keeps the contact stresses from increas- When ordering the Hi Load piston option for Series 2H
ing and permits the Hi Load piston to have a higher side cylinders, please specify K in the piston seal field of
load carrying capacity. This can often reduce or eliminate the model code. The Hi Load piston is standard on all
the need for stop tubing. Series 3H cylinders.

87 Parker Hannifin Corporation
Industrial Cylinder Division
www.parker.com/cylinder Des Plaines, Illinois USA