Name: Bearing Isolator
Brand: Sungturn
SKU: ST-BI
Availability: InStock

Six Major Advantages

Why Choose Sungturn Bearing Isolators?

A bearing isolator — also known as a labyrinth seal or non-contact seal — is a permanent bearing protection device widely used in electric motor protection, pump seals, gearbox seals, and compressor bearing housings. Unlike conventional lip seals that suffer from shaft wear, heat buildup, and limited service life, Sungturn bearing isolators feature a precision labyrinth design with no moving contact surfaces, ensuring zero friction, zero maintenance, and unlimited operating life. As a trusted motor protection solution exported to Europe, North America, and Southeast Asia, Sungturn bearing isolators are the preferred alternative to Inpro/Seal, Garlock, and SKF bearing isolators for industries requiring maximum equipment uptime and minimal maintenance costs.

Six Major Advantages of Bearing Isolators

Key Features

✓
Non-Contact Labyrinth Design
Zero friction, zero wear, zero heat generation — bearing isolators last the lifetime of the machine.
✓
Zero Leakage & Zero Contamination
Precision labyrinth + centrifugal effect blocks lubricant leakage and prevents contaminant ingress.
✓
Maintenance-Free Operation
No scheduled replacement, no lubrication required — dramatically reduces maintenance costs and downtime.
✓
Extreme Temperature Resistance
Operates reliably from −40 °C to +200 °C. Suitable for steel mills, chemical plants, and wind turbines.
✓
High-Speed & High-Load Capable
Non-contact design imposes no speed limit. Proven at shaft surface speeds exceeding 60 m/s.
✓
Universal Drop-In Retrofit
Shaft diameter coverage from 20 mm to 500 mm. Direct replacement — no machining required.

Application Areas

Application of Bearing Isolators

Sungturn bearing isolators are trusted across a wide range of industrial applications for their reliability and performance.

Motors

1. IEEE841 specifies the sealing forms
2. By integrating the conductive fiber shaft grounding technology, the problem of shaft voltage can be effectively resolved.
3. The bearing isolator has no friction and does not consume power.
4. With special structure design, bearing isolator can solve the problem of oil leakage and protection at shaft end of large motor.

Gearboxes

1. Custom internal structural designs are available for different lubrication conditions, including splash lubrication, forced lubrication, and oil bath lubrication.
2. Suitable for both high and low-speed gearbox applications; maintenance-free design provides long-lasting bearing protection.
3. IP66 protection rating, preventing external water vapor from entering the bearing housing during equipment shutdown (ideal for power plant gearboxes and cooling tower fan gearboxes).

Bearing Housings

1. Suitable for rolling bearings, sliding bearings, and split bearing housings, with no modification to the end cover required.
2. Eliminates leakage, requires no maintenance, and is reusable.
3. Can be installed on equipment in steel plants, power plants, paper mills, including rolls, fans, conveyors, agitators, crushers, etc.
4. Designed for challenging conditions such as shaft scoring, large deflection, high vibration, high axial movement, and heavy contamination environments.

Pumps

1. Specified bearing seal design for API 610 chemical pumps.
2. Widely used in ISO/ANSI chemical pumps, nuclear power pumps, high-end fire pumps, circulation pumps, slurry pumps, boiler feed water pumps, and more.
3. Custom designs tailored to operating conditions, including: corrosion-resistant versions with stainless steel or PTFE materials; designs for high axial movement in multi-stage pumps.

Product Gallery

Precision-Engineered Bearing Protection

High-precision machining with excellent adaptability. Bronze and aluminum alloy construction for superior durability and wear resistance.

Standard Bearing Isolator

Bronze or aluminum alloy construction with precision-machined labyrinth grooves. Complete range from 20mm to 205mm shaft diameter.

Magnetic Bearing Isolator

Building on the technology of general-purpose bearing isolators, this product uses impregnated carbon-graphite rings and permanent magnet blocks to form a positive-pressure sealing barrier. It completely blocks external contaminants, prevents lubricant leakage, and causes no damage to the shaft.

IP67 Bearing Isolator

It is ideal for VFD motors in harsh conditions (humidity, water, dust), passing long-term water immersion tests. IP67-rated protection, modified PTFE seal, and anti-scratch shaft sleeve for harsh industrial applications.

Split Bearing Isolator

Suitable for non-disassemblable large equipment including fans, gearboxes, large motors and bearing housings. Split design for both rotating and stationary rings, enabling fast installation and easy maintenance. Available in aerospace-grade anodized aluminum alloy for outstanding corrosion resistance. Optional bronze construction with precision machining for perfect sealing performance.

PTFE Bearing Isolator

PTFE bearing isolator provides cost-effective bearing protection for highly corrosive conditions. Non-contact design prevents shaft damage and allows easy installation, ideal for splash and grease lubrication. Dual O-ring stationary ring enables tool-free mounting and direct replacement of original oil seals. FDA-compliant composite material is available for selection.

Stainless Bearing Isolator

Stainless steel construction for superior corrosion resistance in marine, food & pharmaceutical, and chemical applications. FDA-compliant material options available for washdown and high-humidity environments.

Technical Specifications

ST-A Series Specification Table

Complete range from 20mm to 205mm shaft diameter. Custom sizes available on request.

Product No. 产品编号	Shaft Dia. 轴径 (mm)	Hole Dia. 孔径 (mm)	Total Sealing Thickness 密封总厚度 (mm)	Min. End Cover Thickness 端盖最小厚度 (mm)	Min. External Space of End Cover 端盖外向最小空间 (mm)
ST-A-2046-0	20	46	19	10	9
ST-A-2551-0	25	51	19	10	9
ST-A-2652-0	26	52	19	10	9
ST-A-2854-0	28	54	19	10	9
ST-A-3056-0	30	56	19	10	9
ST-A-3258-0	32	58	19	10	9
ST-A-3359-0	33	59	19	10	9
ST-A-3561-0	35	61	19	10	9
ST-A-3662-0	36	62	19	10	9
ST-A-3864-0	38	64	19	10	9
ST-A-4066-0	40	66	19	10	9
ST-A-4268-0	42	68	19	10	9
ST-A-4571-0	45	71	19	10	9
ST-A-4874-0	48	74	19	10	9
ST-A-5076-0	50	76	19	10	9
ST-A-5278-0	52	78	19	10	9
ST-A-5581-0	55	81	19	10	9
ST-A-5682-0	56	82	19	10	9
ST-A-5884-0	58	84	19	10	9
ST-A-6086-0	60	86	19	10	9
ST-A-6288-0	62	88	19	10	9
ST-A-6389-0	63	89	19	10	9
ST-A-6591-0	65	91	19	10	9
ST-A-6894-0	68	94	19	10	9
ST-A-7096-0	70	96	19	10	9
ST-A-7298-0	72	98	19	10	9
ST-A-75101-0	75	101	19	10	9
ST-A-78104-0	78	104	19	10	9
ST-A-80106-0	80	106	19	10	9
ST-A-83109-0	83	109	19	10	9
ST-A-85111-0	85	111	19	10	9
ST-A-87113-0	87	113	19	10	9
ST-A-90116-0	90	116	19	10	9
ST-A-92118-0	92	118	19	10	9
ST-A-95121-0	95	121	19	10	9
ST-A-98124-0	98	124	19	10	9
ST-A-100126-0	100	126	19	10	9
ST-A-105131-0	105	131	19	10	9
ST-A-110136-0	110	136	19	10	9
ST-A-115141-0	115	141	19	10	9
ST-A-120146-0	120	146	19	10	9
ST-A-125151-0	125	151	19	10	9
ST-A-130156-0	130	156	19	10	9
ST-A-135161-0	135	161	19	10	9
ST-A-140166-0	140	166	19	10	9
ST-A-145171-0	145	171	19	10	9
ST-A-150176-0	150	176	19	10	9
ST-A-155181-0	155	181	19	10	9
ST-A-160186-0	160	186	19	10	9
ST-A-165191-0	165	191	19	10	9
ST-A-170196-0	170	196	19	10	9
ST-A-180206-0	180	206	19	10	9
ST-A-185211-0	185	211	19	10	9
ST-A-190216-0	190	216	19	10	9
ST-A-195221-0	195	221	19	10	9
ST-A-200226-0	200	226	19	10	9
ST-A-205231-0	205	231	19	10	9

* Custom sizes available for shaft diameters below 20mm and above 205mm. Please contact us for full range availability.
* 更多规格可定制，请联系我们获取完整选型表。

Material	Advantages	Best For
Bronze	Excellent wear resistance, self-lubricating, cost-effective	General industrial, pumps, compressors
Stainless Steel (316L)	Corrosion resistance, FDA-approved for food	Marine, food & pharma, chemical
PEEK	Lightweight, chemical resistant, FDA-approved	Food, pharma, high-speed applications
PTFE	Low friction, chemical inert, wide temp range	Specialty chemicals, high-speed

Bearing Isolators