Parker Metric Seals

Back-up rings are the most common anti-extrusion devices in dynamic sealing. They provide simple solutions to safely increase system pressure or solve an existing seal extrusion problem. Backup rings function by positioning a more robust material adjacent to the extrusion gap, taking the seal’s place and providing a barrier against high pressures. Back-ups can be used to offset the reduced pressure rating effects of wear rings or to improve seal life at increased pressures. They can also be used to protect seals against pressure spikes, or to ensure seal performance at higher temperatures.

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BT Cross Section
AY Cross Section
BP Cross Section

BT Profile, Premium U-cup Rod Seal with Secondary Stabilizing Lip

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BT Cross Section

The BT profile is a non-symmetrical design for use in hydraulic rod sealing applications. Using Finite Element Analysis, the BT profile was designed to provide improved sealing performance and stability in the gland. A knife trimming process is used to form the beveled lip which is best for removing fluid from the rod. By design, the BT profile has a more robust primary sealing lip than the BS profile and the stabilizing lip is located at the base of the heel. The standard compound for the BT profile is Parker’s proprietary Resilon® polyurethane compound. The BT profile provides long life, extrusion resistance, low compression set, shock load resistance and increased sealing performance at zero pressure. The BT profile is designed for use as a stand alone rod seal or for use with the BR or OD profile buffer seals for more critical sealing applications.

Technical Data

Standard Materials Temperature Range Pressure Range† Surface Speed
P4300A90 -65°F to +275°F (-54°C to +135°C) 5000 psi (344 bar) < 1.6 ft/s (0.5 m/s)

*Dimensions: according to ISO 5597.

† Pressure Range: without wear rings.


AY Profile, Double-Lip Wiper

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AY Cross Section

The AY profile can be used as a heavy to light duty wiper. When used in high pressure applications with the proper Parker rod seals, the AY complements the sealing system by providing an additional beveled sealing lip, yielding excellent film-breaking and the driest rod sealing available. These dual acting features also enable it to be used by itself in low pressure applications as both the rod seal and the wiper. Knife-trimmed sealing lips ensure the best possible film breaking.

IMPORTANT: When using the AY wiper in conjunction with other rod seals, it is important to select a rod seal profile that enables pressure relief of fluid into the system, otherwise a pressure trap may form between the wiper and rod seal. Suggested rod seal profile is BT Profile u-cup.

Technical Data

Standard Materials Temperature Range Surface Speed
P4300A90 -65°F to +275°F (-54°C to +135°C) <1.6 ft/s (0.5 m/s)

Dimensions: according to DIN ISO 6195, Type C.


BP Profile, Premium TPU Cap Seal

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Metric BP Cross Section

Parker’s metric BP profile is a double-acting, squeeze type, piston seal for use in medium to heavy duty hydraulic applications. The standard material combination for the profile’s components are a TPU cap in Resilon® 4304 polyurethane with improved sliding and high modulus, and a rectangular cross-section NBR elastomer energizer. The BP profile is easy to install on a single part piston. The unique cap design of the BP profile makes the seal insensitive to pressure spikes.

Technical Data

Standard Materials Temperature Range Pressure Range† Surface Speed
Cap
P4304D60 -65°F to +275°F (-54°C to +135°C) 7,000 psi (482 bar) < 1.6 ft/s (0.5 m/s)
Energizer
A 70A Nitrile -30°F to +250°F (-34°C to +121°C)

Dimensions: according to DIN ISO 6195, Type C.

† Pressure Range: without wear rings.


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Parker Distributor Seal Technology Center

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