Sourcing agitator mechanical seals from China

UK duty on agitator mechanical seals

Heading 8484 covers mechanical seals alongside composite metal gaskets and packed assortments of gaskets. Complete agitator mechanical seals are candidates for its mechanical seals, other line, 8484 20 00 90. The table shows configurations within that same line, rather than separate tariff subdivisions.

Read from the UK Trade Tariff on 1 October 2026, the mechanical seals, other line carried 0% duty for goods from China. The supplied tariff record lists no anti-dumping or countervailing duty, suspensions or import controls for this line. Import VAT is normally 20%; see import duty and VAT.

Confirm the commodity code against the complete assembly and its intended use before declaring it. Identify separately supplied elastomer rings and gasket kits rather than assuming they share the assembly's code. For related shaft-seal purchasing advice, see pump mechanical seals.

Specify the agitator shaft and operating conditions

Send a drawing showing shaft diameter, mounting flange, bolt pattern, installation length and available clearance. State whether the agitator is top-entry, side-entry or bottom-entry, its rotation direction, shaft movement and runout. Agree whether the seal is single, double or cartridge-mounted and whether it operates wet or dry.

Describe the process fluid, solids, viscosity, temperature, pressure, vacuum and cleaning cycle. Specify face materials and elastomer grades by name. For a double seal, agree barrier-fluid compatibility, connections and operating instructions. Obtain the supplier's operating limits for the exact assembly.

Finished products must comply with all applicable legislation when placed on the Great Britain market. Agree the compliance evidence appropriate to the supplied assembly through testing and certification. Confirm applicable asbestos restrictions with the relevant authority; ask for an asbestos-free declaration and supporting laboratory evidence for supplied fibre gaskets.

Worked duty example

Illustrative example, not a quote: 40 cartridge agitator mechanical seal assemblies, illustrative only under 8484 20 00 90, invoiced at £30,000 free on board, with £1,500 of freight and insurance to the UK. The customs value is £31,500. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £31,500, so it is £6,300. With no duty, the only import tax is the VAT, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.

Inspection checklist

Fit: measure the shaft bore, flange, bolt pattern and installation length against the approved drawing; check connection positions and cartridge setting instructions.

Faces: inspect for chips and scratches, check face flatness with an optical flat, and match face and elastomer materials to the agreed specification.

Operation: review a leak-test record identifying the assembly, test medium and conditions; agree how the test represents the intended pressure, vacuum and shaft movement.

Arrival: check batch identification, protected sealing faces, corrosion, loose components and installation instructions. Retain the inspection record; see quality inspection.

What goes wrong

A replacement can fit the shaft but fail because its installation length, rotation direction or allowance for shaft movement differs. A wet-running seal selected for dry service can overheat, while incompatible elastomers swell or harden. Abrasive solids can damage faces and obstruct moving parts.

Double seals can leak when barrier connections are misidentified or the operating instructions do not match the installation. Resolve drawing changes and material substitutions before production. Treat a static leak test as evidence of that test, and agree an operating trial for the intended agitator conditions.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For machinery and equipment, see machinery imports.