891 Multi Spring Mechanical Seal

A multi spring mechanical seal uses several small coil springs spread around the seal head instead of one large spring. The springs load the rotary face evenly all the way around, which is what lets the design run at higher pressure and speed than a single-spring seal:

• Higher pressure - up to 2.5 MPa, versus about 1.0 MPa for typical single-spring seals
• Even face loading - no rotating high-spot, so faces wear uniformly
• Better at speed and misalignment - balanced spring force runs smoother at high rpm

For chemical, hydrocarbon and process pumps, the multi spring design is the engineering default. The 891 is the Qixing factory's most-shipped multi spring mechanical seal.

Why Buyers Choose the 891

Two reasons, beyond the 2.5 MPa / 15 m/s envelope. First, metric and imperial in one catalogue: few Chinese seal factories stock inch sizes, so the 891 Multi Spring Mechanical Seal is a natural fit for North American buyers, marine OEMs and oil & gas MRO that need fractional-inch shafts. Second, full material flexibility: any combination of Ceramic, Carbon, SiC or TC faces, NBR / EPDM / FKM elastomer, and SS304 / SS316 / Hastelloy springs, specified at order with no tooling charge above MOQ.

Specifications

Dimensions - Metric (mm)

Shaft diameter d is the seal cavity bore. Confirm before ordering.

Dimensions - Imperial

Inch shaft sizes from 1.000" to 4.000" in 1/8" steps, bores in millimetres. The imperial range is unique to Qixing at this size and lead time.

Applications

• Chemical processing - acid, alkali and solvent transfer (FKM + TC/SiC faces)
• Oil refining and petrochemical - light and heavy hydrocarbon pumps
• Water and wastewater - high-pressure booster and lift pumps
• Pulp and paper - black liquor, white water, recovery boiler auxiliary
• Marine and shipbuilding - seawater cooling, ballast, cargo transfer (imperial sizing)
• Mining - slurry transfer with TC/TC face pair
• OEM pump manufacturing - wholesale multi spring mechanical seal supply

Manufacturing

Faces lapped to ≤ 0.0009 mm flatness and verified optically. Multi-spring loads batch-tested against a master gauge. Spring metallurgy matched to the media at order. Each seal carries a traceable lot number; Certificate of Conformity and material certificate ship with the order at no extra charge for OEM and MRO accounts.

Frequently Asked Questions

How is the 891 different from a single-spring seal?

A single-spring seal loads the face at one point that rotates with the shaft, causing uneven wear and capping out near 1.0 MPa. The 891 uses multiple springs for even loading and roughly 2.5x the pressure capability. Above 1.0 MPa or 13 m/s, the multi spring design is the standard choice.

What is the maximum pressure of the 891?

2.5 MPa continuous, bi-directional. Short higher-pressure spikes are tolerable but should be reviewed with Qixing at quotation so the right face pair and spring grade are specified.

Do you supply the 891 in imperial shaft sizes?

Yes - 1.000" to 4.000" in 1/8" steps, alongside metric 25-100 mm. Imperial ships from the same lead time as metric, with no extra tooling charge above MOQ.

Can the 891 handle aggressive chemicals?

With TC/SiC or TC/TC faces and FKM elastomer it handles weak-to-moderate acids, alkalis and solvents. For strong acids or high-temperature aggressive duty, use the Qixing 58B / 59B Chemical Resistant Mechanical Seal instead.

Quotation

Send the shaft size, face material pair and media for a same-day quotation. Stock sizes ship 3-7 days; OEM custom orders 15-25 days. Buy the 891 multi spring mechanical seal direct from the Qixing factory in China at OEM and wholesale pricing.