pneumatic seal

Pneumatic Seal Selection, Profiles, and Sourcing

Quick Answer: A pneumatic seal contains compressed air and controls leakage in pneumatic cylinders, valves, actuators, and air tools. CORASEALS supplies pneumatic piston seals, rod seals, wiper seals, O-rings, and wear rings in NBR, polyurethane, FKM, and HNBR. Send the cylinder bore, rod diameter, groove dimensions, operating pressure, temperature, air quality, and a sample photo or drawing to get a quote.

Pneumatic seals may look similar to hydraulic seals, but air service is different. Standard pneumatic cylinders operate in a lower pressure range than hydraulic cylinders. Many circuits run between 0.4 MPa and 0.8 MPa. Some industrial systems reach 1.0 MPa to 1.6 MPa. Compressed air is a thin fluid with little lubrication unless an oil mist is present. Friction, wear, seal geometry, and surface finish must be matched to air service. A hydraulic seal profile that works well in oil may not work well in a dry or lightly lubricated pneumatic cylinder.

Pneumatic Seal Types CORASEALS Can Supply

CORASEALS supplies seals for standard and special pneumatic cylinders. The product range includes:

Pneumatic piston seals
Pneumatic rod seals
Pneumatic wiper seals
O-rings for static and dynamic sealing
Wear rings and guide rings
Cushion seals for cylinder end positions

Piston seals use air pressure to drive the cylinder. Rod seals control leakage at the cylinder rod. Wiper seals prevent dust and particles from entering the cylinder. Wear rings support side load and reduce metal contact between the piston and cylinder bore.

Material Selection for Pneumatic Seals

Material selection depends on temperature, air quality, oil mist, wear, and cycle life. Hardness selection matters. O-ring seals are commonly 70 Shore A. Pneumatic polyurethane rod and piston seals are commonly 90 to 95 Shore A. The table below lists common pneumatic sealing materials as a general reference. Confirm the exact grade with the supplier because fillers and hardness change the limits.

Material	Common Pneumatic Use	General Temperature Range
NBR	O-rings, static seals, general air service	-30°C to +100°C
Polyurethane	Rod seals, piston seals, wiper seals, high wear	-20°C to +80°C
FKM	High temperature air, aggressive media, valve seals	-20°C to +200°C
HNBR	Air with oil mist, heat and ozone resistance	-30°C to +150°C

Polyurethane is common for dynamic pneumatic seals because it resists wear and extrusion. NBR is common for O-rings and static seals. FKM is selected when temperature or chemical resistance is more important than low-temperature flexibility.

Dimensions and Profiles

Pneumatic seals are supplied in metric and inch sizes. CORASEALS does not rely only on type codes because the same code may describe different profiles in different catalogues. The most reliable way to match a pneumatic seal is to provide:

Cylinder bore diameter
Rod diameter
Groove diameter, width, and depth
Seal ID, OD, and width
Existing seal drawing or sample photo

If the seal is worn or damaged, measure the groove instead of the old seal. An old seal can swell, shrink, or take a set. The groove is usually the better reference for correct replacement.

Common Failure Causes in Pneumatic Seals

Pneumatic seal failures are often linked to installation, contamination, or operating conditions. Check the following causes before replacing the seal:

Extrusion from excess clearance or high cylinder pressure
Wear from dry air, high speed, or high cycle rates
Seal damage from sharp edges or incorrect installation tools
Hardening or cracking from high temperature or ozone
Swelling from the wrong material or incompatible lubricant

Correct failure diagnosis helps CORASEALS recommend the right material and profile. Send the damaged seal photo and application conditions when requesting a replacement.

Applications for Pneumatic Seals

Pneumatic seals are used in standard cylinders, compact cylinders, rodless cylinders, air valves, actuators, grippers, air tools, and pneumatic control equipment. The same seal profile can be used in different cylinder brands, but the dimensions must be checked. Do not assume interchangeability by type code alone.

Pneumatic Seal Quote Information

For a specific pneumatic seal quote, send the seal type, material, ID × OD × width, operating temperature, pressure, air quality, shaft speed or cycle frequency, drawing, sample photo, and required quantity.

For pneumatic cylinder seal kits, also provide the cylinder bore, rod diameter, stroke, and any original seal kit reference. CORASEALS can match common profiles and custom machined or molded options based on the groove dimensions and application data.

Frequently Asked Questions

What is the difference between pneumatic seals and hydraulic seals?
Pneumatic seals work with compressed air at lower pressure. Hydraulic seals work with oil at higher pressure. Pneumatic seals often use lower friction materials and thinner lubricating films.

Which material is best for pneumatic cylinder seals?
Polyurethane is a strong first choice for dynamic rod and piston seals because of its wear resistance. NBR is common for O-rings. FKM is used for high temperature air or chemical exposure.

Can CORASEALS supply custom pneumatic seals?
Yes. Send the groove dimensions, bore, rod diameter, pressure, temperature, air quality, and required quantity. CORASEALS will match the profile or propose a producible alternative.

How do I measure a pneumatic seal without a drawing?
Measure the groove diameter, groove width, groove depth, cylinder bore, and rod diameter. Take a clear photo of the seal profile. Do not rely only on the worn seal dimensions.

What details do you need for a pneumatic seal quotation?
Send the seal type, material, ID × OD × width, operating temperature, pressure, air quality, speed, drawing, sample photo, and required quantity.

Send your pneumatic seal requirements through the pneumatic seal inquiry page.