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HALLITE SEAL INFORMATION

The following information is provided to assist customers when selecting a Hallite seal for their application. If you need assistance choosing a Hallite product for your application feel free to contact us for assistance.  

 
hallite

HOUSING & INSTALLATION DATA

Hallite 87 & 506 Bearing Strip

Hallite 87 strip is a low friction PTFE & Bronze compound produced in a flat tape style ready for easy cutting to size to suit individual applications and is particularly effective in friction conscious applications such as servo cylinders.

Hallite 506 can be supplied in spiral lengths, generally in 10 meter, as individual cut bearings and also in 10 meter lengths packed flat in a box dispenser. Hallite 506 bearing strip is manufactured to extremely accurate thickness tolerances, ensuring reliable cylinder alignment. Other sizes of type 506 are available on request, special sections and diameters can also be produced to suit individual requirements.

 
Bearing Type Standard Material
87 PTFE + Bronze
506 Polyester + PTFE

Bearing Strip Housing Tolerances

As tolerances are not specified “on line” for Hallite Types 87 & 506, please refer to the information below for tolerances:

 
Hallite 506 Specified Tolerances (mm)
Bearing Length L1 Bearing
Cross Section S
-0.1 to -0.6 -0.02 to -0.1
Hallite 506 Specified Tolerances (in)
Bearing Length L1 Bearing
Cross Section S
-0.005 to -0.015 -0.001 to -0.004

HALLITE 87 & 506 SPECIFIED TOLERANCES

HALLITE 87 & 506 SHAFTS & BORES - METRIC

HALLITE 87 & 506 SHAFTS & BORES - INCH

HOUSING DESIGN

Hallite Seals’ product data sheets give information indicating the allowable extrusion gap a seal can see at pressure during its working life. The extrusion gap can be calculated using the tolerance build ups within the cylinder and any dilation that may occur under pressure. Maximum extrusion gap = F max (see drawing below). F max is the maximum extrusion gap for the seal Minimum metal to metal clearance = F min (see drawing below). F min for cylinders with minimal side loading should be > 0.1mm (0.004”).

Rods

InfoNote: Rod is not concentric with gland, because of clearances.
(shown exaggerated)

InfoNote: Piston is not concentric with cylinder bore, because of clearances.
(shown exaggerated)

Pistons

Calculate both F max and F min.
Ensure the F min is greater than 0.1mm (0.004”) and F max is less than the maximum extrusion gap stated on the seal data sheet at the application’s working pressure.

For built-in metal bearings, the extrusion gap calculation is simpler.

For F max:
Rod = ØD3 max – Ød1 min + dilation
Piston = ØD1max – Ød3 min + dilation

F min must be zero

Extrusion is closely linked to pressure and temperature. In general, the best seal performance and life is provided by specifying the smallest possible extrusion gap. The figures shown for the extrusion gap within the operating conditions of Hallite’s product data sheets, relate to the maximum permissible, worst case situation with the gap all on one side.

HOUSING DESIGN & SEAL OPTIONS

The following diagrams illustrate how Hallite’s wide range of products can be applied to a selection
of some of the most popular cylinder designs servicing the world’s fluid power industry.

The diagrams show different gland and piston arrangements to illustrate alternative sealing methods
currently in use and a suitable Hallite product.

If the application which you are interested in is of a non-standard nature please contact Hallite’s
technical department.

HALLITE SEALS - Storage Guidelines

Most polymeric items including vulcanized rubber and other elastomers tend to change their properties during storage and may become unserviceable. This may be due to hardening, softening, cracking, crazing or other degradation and may be the result of oxygen, ozone, light, heat and/or humidity. Use the the following informational chart for most suitable conditions for storing elastomeric items, whether as a single item or composite product.

 

ENVIRONMENTAL FACTORS

Factor

Recommendations

Temperature

Storage temperatures should not exceed 75°F. Low temperatures are not permanently harmful provided the rubber items are handled carefully and not distorted. When taken from low temperatures items should be raised to approximately 85°F before they are used.

Humidity

Optimum humidity is about 65% in a draft-free atmosphere.

Light

Protection from direct sunlight and strong artificial light with a high ultraviolet content is important. Unless packed in opaque containers, it is advisable to cover windows with red or orange screens or coatings.

Oxygen and Ozone

Elastomeric items should be protected from circulating air wherever possible. As ozone is particularly harmful to rubber, storage rooms should be free from equipment that may give rise to electric sparks or discharge. Wrapping, storage in airtight containers or other suitable means should be used for vulcanised rubber items.

Deformation

Where possible, rubber items should be stored in a relaxed position, free from tension or compression. Laying the item flat and avoiding suspension or crushing keeps it free from strain and minimizes deformation.

Contact with Liquid and Semi-Solid Material

Contact with liquids and semi-solid materials, particularly solvents, such as oils or greases should be avoided unless so packed by the manufacturer.

Contact with Metals

Metals such as manganese, iron and copper, or copper alloys can have a harmful effect on rubber. A layer of paper, polyethylene or cellophane will keep these separated.

Contact with Non-Metals

Contact with other rubbers or creosotes should be avoided.

Stock Rotation

Elastomers should be stored for as short a period as possible, and strict stock rotation should be practiced