Double Lip Dust Seal

Double Lip Dust Seals combine an outward wiping lip with a second lip that helps control lubricant. They are used on rotating shafts in construction equipment, agricultural drives, transmissions, gearboxes, rollers, and similar assemblies exposed to dust, mud, splash, or abrasive debris.

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Product Introduction

Product Overview

Core Advantages

Primary and Secondary Lip Separation
The primary lip maintains contact toward the lubricant side while the outward secondary lip acts as a scraper against external particles. Shafts exposed to mud, silica dust, metal shavings, or crop debris, the two contact zones separate lubricant control from contaminant exclusion so the two jobs are handled by separate contact zones.

Up to 12 m/s Shaft Speed
The profile is specified for shaft speeds up to 12 m/s when surface finish, lubrication, and compound selection are suitable. On reducers, conveyor drives, rollers, and other rotating shafts, this speed capability lets both lips keep working without excessive heat from uncontrolled radial interference.

Controlled Shaft Contact
Hardness is adjustable from 70 to 90 Shore A, with a recommended shaft finish of approximately Ra 0.2 to 0.6 micrometers. During continuous rotation, the combination of controlled hardness and a smooth, lead-free running surface reduces localized scoring while keeping enough contact to block debris.

Elastomer Material Selection & Operating Limits

Selection of the correct polymer compound depends on thermal exposure, chemical compatibility, and peripheral velocity.

Material	Temperature Range	Tensile Strength / Elongation	Primary Industrial Application & Fluid Compatibility
NBR (Nitrile)	-40C to +100C	15-20 MPa / 300-400%	Standard gearboxes, agricultural drives, and mineral-oil-based lubrication systems.
HNBR (Hydrogenated Nitrile)	-40C to +150C	20-25 MPa / 350-450%	High-load automotive transmissions, severe-duty construction equipment exposed to high shear and moderate heat.
FKM (Fluorocarbon / Viton)	-20C to +200C	12-18 MPa / 200-300%	High-temperature industrial pumps, chemical processing gearboxes, and synthetic lubricants.
Silicone (VMQ)	-60C to +200C	6-10 MPa / 150-300%	Low-temperature cold-room drives, electrical motor shafts with minimal mechanical shear.
PU (Polyurethane)	-35C to +110C	35-45 MPa / 400-500%	Heavy-duty hydraulic cylinders, mining scrapers, and extreme abrasive environments.

Technical Parameters

Shaft Speed Capability	Up to 12 m/s (dependent on surface finish, lubrication efficiency, and compound selection).
Shaft Surface Finish Recommendation	Ra <= 0.2 to 0.6 um (Rz <= 1.0 to 4.0 um), ground without spiral lead.
Hardness Range	70 to 90 Shore A (customized according to pressure and structural support needs).
Operating Pressure	Designed primarily for non-pressure or low-pressure splash applications (<= 0.05 MPa).

Customization

Dimensional Range

Inner diameter, outer diameter, axial width, and lip contact angle can be produced in metric, inch, or non-standard dimensions from drawings or physical samples.

Identification and Packing

Color coding, part-number identification on applicable inserts, private-label bags, and carton labeling can be matched to the customer part system.

Quality Control

We check incoming elastomer against the specified compound before molding. Where hardness, tensile properties, compression set, or thermal-aging performance is defined by the project, we verify the required item against the approved material specification.

We check both lip positions as functional dimensions, together with inner diameter, outer diameter, and width. We screen finished profiles for lip edge damage, flash, molding voids, and distortion that could change radial contact between the primary and secondary lips.

We complete final inspection before packing each production lot, including product identity and quantity checks. We accept third-party inspection when required by the purchase specification.