Components
Mechanical Seals for Process Pumps
The mechanical seal is where a process pump most often succeeds or fails. It closes the gap where the rotating shaft passes through the stationary casing, and its selection depends as much on the liquid and duty as on the pump itself.
Why the Seal Is Critical
A seal that is wrong for the service leaks, drives unplanned downtime and can create a safety or environmental problem with an aggressive liquid. Most process-pump reliability programs track seal life closely, because the seal usually reaches the end of its life before the pump does.
Seal Arrangements
Single vs dual
A single seal suits many clean, non-hazardous services. A dual (double) seal adds a second sealing stage with a barrier or buffer fluid for hazardous, toxic or valuable liquids, or where zero visible leakage is required.
Cartridge vs component
A cartridge seal arrives pre-assembled and pre-set, which reduces installation error and speeds change-out. Component seals are built into the pump and can cost less but need careful setting.
Seal Chamber and Support
The seal sits in a seal chamber whose shape affects how well the faces are cooled and kept clean. Standard-bore, big-bore and taper-bore chambers each suit different services, and a flush or support arrangement circulates clean, cool liquid across the faces to extend life. The right combination depends on temperature, solids and the vapor margin of the liquid. YSM series pages list the chamber options available for each family.
The arrangement that circulates or conditions that liquid is described by a numbered API piping plan. API seal flush plans sets out plans 11, 13, 21, 23, 31, 32, 52, 53A/B and 62, and what each one asks of the seal chamber and the pump tappings.
Faces and Materials
Seal faces are chosen from combinations such as carbon, silicon carbide and tungsten carbide, matched to the liquid’s abrasiveness, temperature and chemistry. Our guides go deeper: types of mechanical seals, choosing the face material and replacing a seal.
Mechanical Seal FAQ
What information is needed to select a seal?
The liquid and concentration, temperature, suction and discharge pressure, any solids and whether the service is hazardous or requires zero visible leakage. These decide the arrangement, chamber and face materials.
When should I use a double seal?
For toxic, flammable, crystallizing or environmentally regulated liquids, or where leakage cannot be tolerated. A barrier or buffer fluid then keeps the process liquid contained.
Can YSM match the seal in my existing pump?
Send the pump model, nameplate and the current seal details. We review the arrangement and face materials against your liquid and duty before confirming.
Get a Seal Matched to Your Service
Send your liquid, temperature, pressure and any existing seal details for a reviewed recommendation.
This is general engineering guidance for buyers of ANSI/ASME B73.1 process pumps. Final selection always depends on your verified duty point, liquid data and installation conditions. Send your data for a reviewed proposal.