Quiet parts tend to tell the loudest truths about equipment health. That is exactly what the o ring series does: it seals out ambiguity. Across pumps and motors, hydraulic manifolds and robotic actuators, o rings define whether a system holds pressure, resists media, and survives heat cycles. DEDE has invested decades in getting this right from compound to groove fit, so engineers can stop babysitting leaks and start trusting their assets.
What defines an o ring series
An O‑ring family is more than a circular cross‑section. It is a system of sizes, materials, and durometers that map to global standards and real‑world duty.
· Size systems: AS568 inch sizes, ISO 3601, and JIS B 2401 metric codes organize inside diameter and cross‑section so the same part number fits the same gland anywhere. Proper sizing keeps stretch, squeeze, and gland fill within design windows.
· Static versus dynamic: Static face or radial seals tolerate higher squeeze and pressure. Dynamic motion (reciprocating or low‑speed rotary) demands careful finish, lubrication, and lower compression to avoid abrasion and heat build‑up.
· Durometer: Commonly 70 Shore A for general purpose; 80–90 Shore A for higher pressure or extrusion‑prone clearances; softer 50–60 Shore A for low‑temperature sealing and delicate housings.
· Gland types: Piston, rod, and face glands each target different squeeze geometry. Backup rings are added when pressure and extrusion gaps push limits.
Materials and the performance envelope
Selecting the right elastomer is the one lever that changes everything—chemical resistance, temperature window, compression set, and long‑term resilience. The o ring series typically spans these compounds:
· NBR nitrile:
Strengths: Petroleum oils and fuels, good abrasion resistance.
Typical temperature: −40 to 125°C depending on acrylonitrile content.
Uses: General hydraulics, gearboxes, engines.
· EPDM:
Strengths: Steam, hot water, many polar chemicals; excellent weathering.
Typical temperature: −40 to 125°C.
Uses: Water treatment, braking systems, HVAC, household appliances with water.
· FKM fluoroelastomer:
Strengths: Oils, fuels with ethanol, many solvents; low gas permeability.
Typical temperature: −20 to 250°C.
Uses: Pumps and valves in chemical service, engine bays, energy sector.
· VMQ silicone:
Strengths: Wide low‑temperature flexibility, good thermal stability.
Typical temperature: −60 to 225°C.
Uses: Aerospace connectors, electronics, static seals with low clamping force.
Pressure reality check: in static glands with tight clearances and 90‑durometer compounds plus backup rings, O‑rings can seal very high pressures. As pressure climbs, extrusion risk rises quickly; many designs introduce backups around 10–15 MPa, earlier for large gaps or high temperatures. In dynamic motion, friction and heat lower the safe ceiling; reciprocating applications often trade pressure margin for longer life.
O‑ring is only as good as its groove and installation. A few rules carry most of the load:
· Squeeze and stretch: Target 10–30% radial squeeze depending on duty; keep installed ID stretch around 2–5% for dynamic seals and up to ~8% for static, while avoiding compression set over time.
· Gland fill: Aim for ≤85% at maximum swell and thermal expansion. Overfilling accelerates wear and increases assembly damage.
· Surface finish: Fine Ra on mating surfaces reduces abrasion and micro‑leak paths, especially in dynamic seals. Hard anodized or coated pistons/rods help.
· Lubrication: Compatible assembly lube prevents nicks and reduces startup friction. For oxygen service or food contact, use approved lubricants.
· Backups and clearances: When extrusion gaps cannot be tightened, add single or double backups. Choose PTFE for chemical breadth.
· Installation discipline: Lead‑in chamfers, deburred edges, and avoiding twist during fitment prevent spiral failure and cuts—two of the most common, avoidable issues.
O-ring series application
· Pumps and valves: Static casing joints, mechanical seal secondary seals, and instrument tap plugs rely on elastomers that match media—from potable water EPDM to solvent‑service FKM.
· Motors, gearboxes, and engines: Cover plates, inspection ports, and connector interfaces commonly use NBR for oil resistance and stable compression set under heat.
· Hydraulic and pneumatic systems: Manifolds, cylinders (piston and rod glands), and quick‑connects mix NBR with backups for pressure, or low‑friction blends for pneumatics.
· Industrial machinery and robotics: Actuators, end‑effectors, and tool changers prioritize repeatability—material choice balances wear with low compression set.
· Energy sector: Wind turbines, conventional power, and oilfield auxiliaries see wide temperature ranges; FKM and low‑temperature compounds provide margin.
· Construction and agricultural equipment: Field shocks and contamination make gland design and backup selection as important as compound.
· Metallurgy and chemical processing: High temperature and aggressive media push toward FKM; groove fill control becomes critical during swell.
· Water treatment: EPDM dominates for hot water and chloramine resistance; hygiene‑focused compounds support disinfection cycles.
· Transportation: Rail, aviation, automotive, and heavy trucks need predictable aging and vibration tolerance—validated compounds and controlled durometer are the foundation.
· Household appliances: Pumps, valves, and manifolds in washers and
dishwashers depend on water‑compatible EPDM and careful gland fills to handle
thermal cycling.
How we support you
DEDE is a manufacturing brand with more than three decades focused on oil seals and O‑rings, supported by ERP and certified quality systems. The factory footprint, dedicated R&D, and standardized management underpin reliable scale and consistency across batches.
· Standard inventory, fast shipment: More than ten thousand specifications across O‑rings, oil seals, and related profiles, held for quick response to urgent production or maintenance needs.
· End‑to‑end customization: From material selection and groove design to prototyping and validation testing, we build non‑standard seals matched to your media, pressure, motion profile, and installation constraints.
· Technical enablement: With 30+ years in the field, our engineers help optimize sealing performance, control compression set and wear, and lower maintenance cost through better compounds and glands.
DEDE Highlights
· Manufacturing capability: Entity factory with intelligent manufacturing practices and process control that scales from prototypes to volume.
· Industry standing: Recognized for sealing expertise and long‑term reliability across diverse sectors.
· Breadth of models: A wide catalog with extensive on‑hand inventory reduces waiting and simplifies qualification.
· Global reach: Products shipped to customers in 80+ countries, supporting multinational maintenance and production teams.
· Brand recognition: DEDE is known by many industrial buyers for consistent quality over time.
· Innovation credentials: Provincial technology innovation center, provincial “specialized and innovative” enterprise status, and high‑tech enterprise qualifications.
· Ecosystem role: Active participant in a specialized industrial cluster, collaborating upstream and downstream to improve availability and performance.
A practical path to the right O‑ring
· Medium first: Match elastomer to chemistry; for mixtures, choose the limiting fluid and consider worst‑case concentration and temperature.
· Thermal reality: Use the real bracket—startup lows, steady‑state highs, and spikes. Add margin for hot spots and soak.
· Pressure and motion: Define maximum pressure and extrusion gap. If you cannot tighten clearances, step up durometer and add backups. For dynamic seals, value low friction and good wear resistance over brute force squeeze.
· Size standard and tolerance stack: Decide on AS568/ISO/JIS early to align with readily available glands and spares. Validate gland fill at max swell.
When you are ready to specify, bring us your constraints and the duty that worries you most. The o ring series works best when it is designed around the toughest minute your system will see. DEDE will help you seal that moment—and the thousands that follow—with a combination of compound science, disciplined groove design, and a supply chain built to keep you running.
