KAIFIL supplies O-ring seals for metal filter end connections, cover grooves and removable filter assemblies. NBR, EPDM, FKM and silicone compounds are available in metric and AS568 size series, with compound, hardness and section selected for the sealing groove.
Share a drawing, reference sample or application requirements to discuss the configuration.
Black EPDM O-ring seals
Large-diameter O-rings with circular cross sections
O-ring seals in assorted sizesBlack EPDM O-ring seals
An O-ring develops sealing contact when its circular cross section is compressed inside the groove. In filter assemblies, this supports compact face seals and radial seals at end connections or covers. We specify the free-state inside diameter and cross section together with the groove dimensions so the ring seats correctly during assembly.
Specify metric rings as inside diameter × cross section, in millimeters. AS568 rings are identified by dash number; common nominal cross sections include 1.78, 2.62, 3.53, 5.33 and 6.99 mm. These are separate size families, not interchangeable steps in the same groove. For an existing seal, measure an unused ring or use the original part drawing rather than a stretched service sample.
NBR is a practical choice for compatible mineral oils and lubricants. Common hardness selections are 70 and 90 Shore A. Select hardness alongside groove clearance and assembly force: the harder ring can resist extrusion better, while the seal geometry must still provide the intended compression.
EPDM is used for water-based filter duties and compatible cleaning solutions; 70 Shore A is a common selection. Peroxide-cured compounds can be specified for demanding hot-water and cleaning cycles. Keep mineral oils and petroleum-based lubricants out of the EPDM material selection and installation process.
FKM offers useful resistance to many oils and fuels and is selected for elevated-temperature duties with compatible media. Common hardness options are 75 and 90 Shore A. Silicone provides temperature flexibility for static joints but needs careful handling at sharp groove edges. Hot water, steam, solvents and cleaning cycles should be checked against the exact compound, rather than the polymer name alone.
Remove burrs and protect the ring from exposed threads during installation. Use a compatible lubricant, keep the ring untwisted and inspect that it is fully seated before closing the joint. Groove depth controls squeeze; groove width provides room for deformation and swelling. A larger cross section should not be used simply to compensate for a damaged groove.
Filter-end O-rings seal the removable connection between the element and its housing seat. Cover O-rings seal the housing closure; these are separate positions in the service kit. For 222 and 226 cartridge connections, identify the actual seal position, groove and mating bore with the end fitting. Record free-state ring size, compound, hardness and quantity for each position. Assembly inspection checks a clean groove, untwisted seating and continuous engagement after insertion.
| Component / interface | Defined function and inspection |
|---|---|
| Cartridge end fitting | Identifies the element-side groove and seal position |
| Housing bore or cover | Defines the mating sealing surface |
| O-ring | Free-state ID × cross section, compound and hardness |
| Lead-in and groove edge | Smooth entry protects the sealing surface |
| Service kit | Position, quantity and material identity remain separate |
| Nominal section (mm) | Nominal section (in) | Size definition |
|---|---|---|
| 1.78 | 0.070 | Free-state circular-section diameter; inside diameter is selected by the individual dash size. |
| 2.62 | 0.103 | Free-state circular-section diameter; inside diameter is selected by the individual dash size. |
| 3.53 | 0.139 | Free-state circular-section diameter; inside diameter is selected by the individual dash size. |
| 5.33 | 0.210 | Free-state circular-section diameter; inside diameter is selected by the individual dash size. |
| 6.99 | 0.275 | Free-state circular-section diameter; inside diameter is selected by the individual dash size. |
| Supply item | Order basis |
|---|---|
| Production lead time | 2–3 weeks after order and drawing confirmation. |
| Trial orders | Small trial quantities for fit and process evaluation. |
| Regular production orders | 50 pieces or US$3,000 per order. |
| Quotation basis | Material, finished dimensions, section geometry, mating interface and quantity. |
| Parameter | Specification | Notes |
|---|---|---|
| Cross-section shape | Circular | O-ring for a designed face or radial groove. |
| Size systems | Metric / AS568 | Metric: ID × CS; AS568: dash number. |
| Material options | NBR / EPDM / FKM / VMQ | Choose the compound and cure system for all fluid exposure. |
| Common hardness options | NBR 70 or 90; EPDM 70; FKM 75 or 90 Shore A | Hardness is specified by material, not as one shared value. |
| AS568 nominal cross sections | 1.78 / 2.62 / 3.53 / 5.33 / 6.99 mm | These are five separate nominal cross-section families. The dash number also defines the free-state inside diameter. |
| Free-state dimensions | Inside diameter × cross section | Use the uninstalled, unstretched dimensions. |
| Outside diameter relationship | OD = ID + 2 × CS | Geometric relationship for an unstretched circular-section ring. |
| Groove data | Depth / width / diameter / clearance | Include mating-surface finish and assembly lead-in. |
| Seal arrangement | Static face / static radial | Filter connections, covers and removable inserts. |
| Color identification | Black / compound-specific colors | Color is recorded separately from material and hardness. |
| Supply format | Individual sizes / matched seal kits | Label each ring by position, material, size and hardness. |
Materials: NBR, EPDM, FKM and silicone (VMQ). Compound and cure system are selected for the process fluid, cleaning exposure and temperature cycle.
Examine the part profile, contact faces and construction details.
Large-diameter O-rings with circular cross sections
O-ring seals in assorted sizes
Include these details when discussing your requirements.
Circular-section rings seal the groove between a filter end fitting and its mating seat.
Matched O-rings support repeatable assembly around machined connections.
Groove seals close the designated joint at basket housings and removable covers.
For a metric ring, provide free-state inside diameter × cross section. For AS568, provide the dash number. Add material and hardness to make the order description complete.
No. Several polymers can be black, and the same polymer can be produced in different colors. Use the compound specification or material record.
Material selection follows the fluid. FKM is useful for many oils and fuels; EPDM is frequently selected for water and compatible aqueous cleaning. The cleaning cycle can change the preferred compound.
Hardness influences deformation and extrusion resistance, but pressure capability also depends on groove clearance, section, temperature and mating parts. Select hardness as part of the complete groove design.
A used ring helps identify the general profile, but swelling, stretch and compression can change its dimensions. A groove drawing, original specification or unused sample gives a better replacement basis.
Yes. We organize rings by sealing position and mark the material, size, hardness and quantity for each position.
Explore related products and technical guidance.
KAIFIL supplies flat sealing gaskets for metal filter end faces, basket seats and removable filter holders.
View details
Kaifil manufactures stainless steel flanged filter cartridges with wedge wire, woven mesh, sintered mesh, perforated metal or pleated filtering bodies.
View detailsDefine the dimensions, media, joints and inspection records before confirming the order.
