Component Mechanical Seals for Pumps and Rotating Equipment

A component seal is selected as individual sealing parts rather than as a complete pre-set cartridge assembly. The rotating seal, stationary seat, secondary seals and setting dimensions must suit the equipment and operating duty.

Match more than the shaft diameter

Two seals with the same nominal shaft size can have different working lengths, seat dimensions, materials and operating limits. A similar-looking seal is not enough to confirm interchangeability.

The replacement needs to match the rotating assembly and stationary seat, the available installation space, and the equipment's required setting arrangement. Use the relevant equipment drawing and seal instructions where available.

What to send for identification

• Pump or equipment make, model and any drawing or part number.
• Shaft or sleeve diameter at the seal location.
• Photographs of the complete old seal, both faces, the stationary seat and any markings.
• Seat outside diameter, housing dimensions and the required working length, where known.
• Process fluid, concentration, normal and maximum temperature, pressure and speed.
• Cleaning fluids, steam exposure or other changes in duty.
• What happened before the seal was removed, including leakage, dry-running events or repeated failures.

If a dimension is unknown, say so. Do not estimate a working length from a damaged or uncompressed old seal and treat it as a confirmed setting dimension.

Choose the faces and secondary seals for the process

Face materials and secondary seals need checking together. Fluid chemistry, solids, temperature, pressure, lubrication and cleaning conditions can affect the choice. A carbon, silicon carbide, tungsten carbide or elastomer name does not establish that every combination suits the duty.

Food or pharmaceutical applications may also require specific material documentation. Confirm the requirement for the selected parts rather than assuming a general material description proves compliance.

Component seal or cartridge seal?

A like-for-like component replacement may be suitable when the existing arrangement and duty are established. A cartridge alternative can be considered where the equipment dimensions, access and support requirements allow it. Conversion is not automatic, and changing the seal does not by itself correct a pump or process problem.

If the last seal failed early

Keep the removed parts and record how the equipment was operating. The damage pattern, failure timing, process conditions and support arrangement can be more useful than ordering the same part again. Photographs can help start the review, but inspection or further measurements may be needed. See our Failure analysis guidance.

Send the pump and seal details

Start with the information you have. We will check what is missing before recommending the replacement.