01 · SEALS
Reciprocating Seals
for Rods, Pistons and Plungers.
Plunger cups, U-cups, rod and piston seals, V-packings and wipers — moulded to your stroke, working pressure and clearance gap at our ISO 9001:2015 plant in Nashik. A reciprocating seal is not an oil seal with a different name: it has no garter spring, it works a stroke rather than a rotation, and the rod finish matters more than the compound.
- ISO 9001:2015
- MADE TO YOUR HOUSING
- 8 COMPOUNDS IN-HOUSE
02 · FIND YOUR SEAL
Seals Are Sorted by Motion, Not by Shape
What a seal has to do is decided by how the parts move against each other. Get that right and the rest — compound, hardness, section — follows. Below is where each family lives on this site.
01Do not move — a clamped joint in a groove
02Do not move — a bolted flange or face
03Rotate — a turning shaft in a housing
04Flex — a membrane deflecting under pressure
05Stroke — a rod or piston moving in and out
03 · TYPES
Six Sections, Chosen by Pressure and Duty
These are pressure-energised sections: the medium pushes the lip against the sealing surface, so the seal grips harder as pressure rises and runs light when it falls. Which section suits depends on the pressure, whether the duty is single or double acting, and how much clearance the housing leaves.
Plunger cups
A cup-section seal on a plunger, sealing on its outside diameter against the bore. Single acting, tolerant of a less precise bore than a U-cup, and the section that has been in service longest.
Typical useDosing and metering pumps, sprayers, hand and foot pumps
U-cups
A U-section lip seal for a rod or a piston, single acting. The lip is energised by pressure and relaxed without it, so it runs cooler and drags less than a squeezed section.
Typical useLow and medium-pressure cylinders, pump rods
Rod seals
Seals on the rod, keeping the medium inside the cylinder. Sized to the rod diameter, the groove and the clearance — housings to ISO 5597 where the design follows the standard.
Typical useActuators, jacks, press rams
Piston seals
Seals on the bore, keeping pressure on one side of the piston. Single acting to ISO 6547, or paired back to back for double acting.
Typical useSingle and double-acting cylinders
V-packings and chevron sets
Stacked V-rings between a male and a female adaptor, adjustable by the gland. The set is tightened as it wears rather than replaced, which suits plant that cannot be stripped often.
Typical usePlunger pumps, valve stems, high-wear duty
Wipers and scrapers
Keep dirt, dust and moisture off the rod on the return stroke. Not pressure seals — they protect the rod seal behind them, and they are the cheapest part in the assembly to renew. Housings to ISO 6195.
Typical useAny rod running in a dirty environment
04 · SPECIFICATION
What We Need to Quote
| Input | Range | Why we ask |
|---|---|---|
| Rod or bore diameter | Ø6 mm – Ø250 mm | Set by tooling, not by the compound. Larger is quotable against the part |
| Groove dimensions | to drawing | Width and depth, and whether the groove is closed or split |
| Clearance gap | to drawing | The row most enquiries omit. Pressure and clearance together decide whether a back-up ring is needed — see section 06 |
| Stroke | to drawing | Governs heat build-up and wear rate |
| Working pressure | to drawing | Continuous and peak, separately. They are different numbers and both matter |
| Medium | named fluid | Decides the compound. The input most often left out |
| Service temperature | −60 to +250 °C across the eight compounds | Narrows the compound with the medium |
| Rod or bore surface finish | Ra, µm | The single biggest cause of premature failure. See section 06 |
| Hardness | 70 – 90 Shore A | Our output, not your input. Reciprocating sections run harder than static ones |
| Dimensional tolerance | ISO 3302-1 class M1 | Tolerance follows the section, as on every moulded part in this catalogue |
Send a drawing in PDF, DWG, DXF or STEP — or send the seal you are replacing and tell us how it failed. A hardened, glazed lip means heat or a rod finish that is too smooth to carry a film; a lip nibbled on one edge means extrusion into the clearance; scoring across the lip means the rod is too rough or the wiper has failed.
05 · COMPOUND
The Medium Decides. The Pressure Sets the Hardness.
A reciprocating seal is submerged in the medium and dragged across a surface thousands of times an hour, so the compound is chosen for the fluid and the hardness for the pressure. Every compound we mix is available. These are ranked for reciprocating duty.
| If the medium is | Compound | Service temperature | Note |
|---|---|---|---|
| Mineral oil, hydraulic fluid, grease, fuel | NBR | −30 to +120 °C | The default for reciprocating duty and the compound most of this category is made from. Good abrasion resistance at seal hardnesses |
| Water, coolant, steam, dosing chemicals, brake fluid | EPDM | −40 to +140 °C | The default for pumps handling water and dosing chemistry. Never in mineral oil |
| Solvents, aggressive chemistry, hot hydrocarbons | FKM | −20 to +250 °C continuous to +200 °C | The escalation when NBR is out of range on temperature or medium. Poor in the cold, and it fails in steam and glycol brake fluid |
| Hot oil above nitrile’s ceiling | AEM | −40 to +175 °C continuous to +160 °C | The middle answer between NBR and FKM at well under FKM cost. Absent from almost every competitor’s menu |
| Refrigerants, marine, moderate oil | Neoprene | −40 to +120 °C | General purpose, with flame-retardant grades where a fire rating is specified |
| Low pressure, high stroke, water or air | Natural rubber | −20 to +90 °C | Best flex-fatigue resistance of the eight. Too soft for pressure duty and no oil contact — a narrow but real fit |
| Abrasive water, low cost | SBR | −30 to +100 °C | Where abrasion governs and pressure is low. No oil contact |
| Clean, high temperature, very low pressure | Silicone | −60 to +220 °C | Almost never right on a reciprocating seal. Low tear strength and poor abrasion resistance, and it extrudes readily — three properties this duty punishes. Available, and we will say so if you ask for it |
For high-pressure hydraulic rod and piston seals, polyurethane is usually the correct material and we do not mould it. Our reciprocating seals are rubber, for pump, sprayer, dosing and lower-pressure cylinder duty. If your specification calls for polyurethane, we will tell you rather than substitute.
06 · WHAT KILLS THEM
Most Reciprocating Seals Fail on the Housing, Not the Seal
Surface finish
Extrusion and the clearance gap
07 · QUALITY
Tested Before It Ships
| Property | Method | Where |
|---|---|---|
| Hardness | ASTM D2240 | In-house |
| Tensile and elongation | ASTM D412 | In-house |
| Compression set | ASTM D395 Method B | In-house |
| Tear strength | ASTM D624 | NABL partner laboratory |
| Abrasion loss | ISO 4649 · ASTM D5963 | NABL partner laboratory |
| Fluid immersion / volume swell | ASTM D471 | NABL partner laboratory |
| Dimensional conformity | ISO 3302-1 class M1 | In-house |
| Dynamic seal life / cycles to failure | — | no test rig |
Material test reports, dimensional inspection sheets and a certificate of conformance ship with every consignment. Batch records are retained per shipment and are available on request under NDA. Seals are packed so the lip is not deformed in transit.
ISO 9001:2015 · Certificate 09111526A
Integral Certification Ltd · Valid to 21 February 2027
Scope: rubber moulded components — quality management, not a product approval
IATF 16949 — upgrade in progress, certification targeted by end 2026
ISO 14001 and ISO 45001 — targeted 2027
FREQUENTLY ASKED QUESTIONS
Technical & commercial questions
10 · ENQUIRIES
Request a Seal Quotation
Send the rod or bore diameter, the groove, the clearance and the working pressure — or send the seal that failed and the rod finish, and we will tell you what killed it. Our engineering team responds within 48 hours with a section and compound recommendation, dimensional confirmation and a quotation.