Liquid Silicone Insulating Gasket for Transformers High Temperature Resistant

# Liquid Silicone Insulating Gasket for Transformers (High Temperature Resistant)

Product Overview

Our Liquid Silicone Rubber (LSR) Insulating Gasket for Transformers is a high-performance sealing and insulating component engineered specifically for medium- and high-voltage power transformer systems, addressing the critical demands of long-term operation under extreme thermal, electrical, and mechanical stress. Manufactured via precision injection molding of food-grade, high-purity liquid silicone rubber, this gasket delivers exceptional dielectric strength, thermal stability, and weather resistance, outperforming traditional EPDM, neoprene, and nitrile rubber gaskets in transformer applications.

Core selling points include a continuous operating temperature range of -60°C to 220°C (with short-term resistance up to 250°C), zero brittleness or performance degradation after 1000+ hours of thermal aging, and a 15+ year service life in enclosed transformer environments. The gasket is designed to form a hermetic seal between transformer tank flanges, bushing mounting surfaces, cooling system interfaces, and tap changer compartments, preventing leakage of insulating oil and ingress of moisture, dust, and other contaminants that could compromise transformer insulation performance. It is compatible with all conventional transformer insulating oils, including mineral oil, ester-based synthetic oil, and silicone oil, with no measurable weight change or mechanical property loss after 180 days of immersion.

Technical Specifications

Material Properties

All gaskets are formulated with platinum-cured addition-type liquid silicone rubber, free of low-molecular-weight siloxanes, plasticizers, and volatile organic compounds (VOCs) to avoid contamination of transformer insulating fluid. Key material properties are as follows:

Physical Performance

The gasket’s mechanical and electrical properties are optimized to withstand the dynamic operating conditions of power transformers:

Process Parameters

All gaskets are manufactured with tight dimensional tolerances to ensure perfect fit with standard and custom transformer flanges:

Product Advantages

1. Superior Long-Term Thermal Stability

Unlike conventional rubber gaskets that harden, crack, or lose elasticity after 3~5 years of operation at 100°C+, our LSR gaskets maintain 90% of their original tensile strength and elongation after 1000 hours of continuous aging at 180°C, eliminating the need for frequent gasket replacement during transformer maintenance cycles and reducing unplanned downtime.

2. Exceptional Dielectric Insulation Performance

The high-purity silicone formulation delivers consistent dielectric strength even after long-term exposure to moisture, oil, and electrical stress, preventing partial discharge and insulation breakdown at the flange interface. Its low dissipation factor minimizes energy loss from capacitive heating, improving overall transformer operational efficiency by 0.2~0.5% compared to EPDM gaskets.

3. Reliable Hermetic Sealing Performance

With a compression set of ≤8% at 150°C, the gasket maintains consistent contact pressure on flange surfaces even under thermal cycling, vibration from transformer core operation, and pressure fluctuations from insulating oil expansion and contraction. It eliminates oil leakage risks even at internal pressures up to 1.2 MPa, complying with IEC 60076 leakage tightness requirements for power transformers.

4. Broad Chemical Compatibility

The gasket is inert to all common transformer insulating fluids, corrosion inhibitors, and outdoor environmental contaminants including sulfur dioxide, ozone, and salt spray. It shows no degradation or leaching of harmful substances after decades of immersion in mineral oil, avoiding contamination that could reduce the insulating performance of transformer oil.

Applications

Our LSR insulating gaskets are designed for use across all types of oil-immersed and dry-type transformer systems:

1. Power Transformer Sealing: Flange gaskets for main tank bodies, radiator interfaces, conservator tanks, and bushing mounting plates in 10kV ~ 1000kV power transformers, including both pole-mounted and substation-installed units.
2. Distribution Transformer Components: Seals for tap changer compartments, oil level gauge interfaces, explosion vent assemblies, and low-voltage side terminal boxes in 10kV ~ 35kV distribution transformers for residential and industrial power grids.
3. Specialty Transformer Applications: Insulating gaskets for traction transformers in high-speed rail and urban rail transit systems, offshore wind farm transformers (with enhanced salt spray resistance), and high-temperature industrial transformers for steel mills and smelting facilities.
4. **Transformer Accessory Sealing: Gaskets for cooling system pumps, oil filtration equipment, and on-load tap changer drives, providing both sealing and electrical isolation between metal components to prevent stray current corrosion.

*Application Note: For transformers operating in altitude regions above 3000m, we recommend selecting gaskets with a dielectric strength rating of ≥25 kV/mm to compensate for reduced air insulation performance at high altitudes. For offshore applications, add a UV-stabilized surface coating to extend service life to 20+ years.*

Selection Guide

Hardness Selection

• 40~45 Shore A: Recommended for uneven flange surfaces, low-pressure transformers (<0.3 MPa internal pressure), and applications requiring high conformability to seal minor surface defects.
• 50~55 Shore A: Standard grade for most 10kV ~ 110kV power transformers with flat flanges, balancing sealing performance and mechanical durability.
• 60~70 Shore A: Recommended for high-pressure transformers (>0.8 MPa internal pressure), large flange diameters (>800mm), and applications with high mechanical vibration loads, reducing gasket extrusion and creep under long-term stress.

Size Specifications

• Standard sizes are available for all IEC 60076 and GB/T 10237 standard transformer flanges, with pre-configured hole positions matching common bolt spacing.
• Custom sizes are available for non-standard transformer designs: provide flange drawing, outer diameter, inner diameter, thickness, and hole position details when placing an order, and we will provide a dimensional verification report within 2 working days.
• For new transformer designs, our engineering team can provide gasket design optimization services to minimize sealing stress and improve long-term reliability.

Material Grade

• Standard Industrial Grade: Suitable for most indoor and outdoor substation transformer applications, RoHS 2.0 and REACH compliant.
• High Thermal Conductivity Grade: For transformers with high heat load, 0.8~1.2 W/(m·K) thermal conductivity to improve heat dissipation from flange surfaces, reducing operating temperature by 3~5°C.
• Flame Retardant Grade: UL94 V-0 rated, recommended for transformers installed in indoor substations, underground power facilities, and other locations with strict fire safety requirements.
• Food Grade: For transformers used in food and beverage processing facilities, pharmaceutical factories, and drinking water treatment plants, complying with FDA 21 CFR 177.2600 and EU 10/2011 food contact standards.

Quality Assurance

All our LSR transformer insulating gaskets are manufactured in an ISO 9001:2015 certified facility, with strict quality control at every production stage:

1. Incoming material inspection: Each batch of LSR raw material is tested for purity, dielectric strength, and oil compatibility before entering production, with traceability records for all raw material batches.
2. In-process inspection: Dimensional verification is performed on every 50th unit during production, with 100% visual inspection for surface defects, flash, and voids.
3. Finished product testing: Each production batch undergoes random sampling for compression set testing, dielectric strength testing, and oil immersion testing to ensure compliance with stated specifications.
4. Certification: All products comply with IEC 60311 electrical insulation rubber standards, RoHS 2.0, REACH SVHC, and UL safety requirements. Third-party test reports from CNAS or ILAC accredited laboratories are available on request.

We offer a 10-year warranty against material defects and performance degradation under normal operating conditions, with free technical support for gasket installation and maintenance guidance. In case of product non-conformity with stated specifications, we provide free replacement or full refund according to our quality commitment policy.