Page 100 - Parker - Heavy Duty Hydraulic Cylinders

Catalog HY08-1114-4/NA Heavy Duty Hydraulic Cylinders
Common Modifications Series 2H / 3H Custom Modifications

Modifications: The following modifications can be Rod End Boots
supplied on most Parker cylinders. Cylinders have a hardened bearing surface on the
piston rod to resist external damage, and are equipped
Metallic Rod Wiper with the high efficiency “Wiperseal” to remove external
When specified metallic rod wipers can be supplied dust and dirt. Exposed piston rods that are subjected
instead of the standard synthetic rubber wiperseal. to contaminants with air hardening properties, such as
Recommended in applications where contaminants tend paint, should be protected. In such applications, the use
to cling to the extended piston rod and would damage of a collapsing cover should be considered. This is
the synthetic rubber wiperseal. Installation of metallic rod commonly referred to as a “boot”. Calculate the longer
wiper does not affect cylinder dimensions. It is available rod end required to accommodate the collapsed length
at extra cost. of the boot from the following data.
Parker Crown Wiper™ for Series 2HD
and 7" & 8" bore 3HD LF .13 .13 .13 .13 .13 .13 .13 .10 .10 .10 .10 .10
For environments that contain fine abrasive particulate OD 2.25 2.25 2.63 3.00 3.38 3.75 4.38 5.13 5.63 6.25 7.00 7.50
specify the Crown Wiper option. The Crown Wiper is a MM .500 .625 1.000 1.380 1.750 2.000 2.500 3.000 3.500 4.000 5.000 5.500
proven superior alternative to piston rod end boots or To determine extra length .50 .63
metallic wipers that can ingest particulate. It has a sharp of piston rod required to
leading edge to effectively clean the piston rod and a accommodate boot, calculate
beveled shape to prevent contaminant intrusion by BL = Stroke x LF + 1.13"
channeling it away from the gland. It also acts as a BL + Std. W + A = length of piston
secondary seal to wipe clean any oil film adhering to the rod to extend beyond the retainer. ØMM OD
rod on the extend stroke. NOTE: Check all Boot O.D’s
against std. “E” dimension from
Standard Crown Wiper material for Seal Class 1 and catalog. This may be critical on
2 service is durable polyurethane. Optional FKM foot mounted cylinders.
material is available for Class 5 service. The Crown BL
Wiper requires a unique gland but does not change Gland Drain
cylinder mounting dimensions Hydraulic fluids tend to adhere to the piston rods, during
the extend stroke, and an accumulation of fluid can
collect in the cavity behind the gland wiperseal on long
stroke cylinders.
Crown Wiper A /8" NPTF gland drain port can be provided in the
1
gland retainer. A passage in the gland between the
wiperseal and lipseal is provided to drain off any accu-
mulation of fluid between the seals. See drawing below.
It is recommended that the gland drain port be piped
back to the fluid reservoir and that the reservoir be
located below the level of the head of the cylinder.
On 1.50" bore with 0.625" rod the drain port is located in
the head adjacent to the port. The retainer thickness on
1.50" bore with 1.000" rod and gland drain is increased
to 0.63". On 2.00"-
8.00" bore sizes the
drain port is located
in the retainer as
Crown Wiper Rod Gland Kits are available to retrofit shown. On Style JJ
existing 2HD & 3HD cylinders. See 2HD/3HD Parts List with gland drain and
and Seal Kits page. 1.000"-4.000" rods
the retainer thick-
ness is increased
by 0.25".

Air Bleeds
In most hydraulic circuits, cylinders are considered
self-bleeding when cycled full stroke. If air bleeds are
required and specified, /8" NPTF Air Bleed Ports for
1
venting air can be provided at both ends of the cylinder
body, or on the head or cap. To order, specify “Bleed
Port”, and indicate position desired.

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