When tackling pump leakage issues, repeat seal failure, or choosing a suitable sealing solution for a critical process, the first step is to grasp the understanding of mechanical seals for pumps UK industrial environments demand. When it comes to selecting the right seal for the job, things go wrong very fast – leakage, unexpected downtime, product contamination and in regulated industries – an HSE compliance problem that halts production and sets the clock ticking for the investigation. The Fluid Sealing Association (FSA) says mechanical seals eliminate product leakage by more than 90% compared to conventional gland packing systems, and add substantial reliability benefits to the pump. This performance benefit is a clear trend throughout industry in the UK. The problem for the maintenance engineers, reliability engineers and purchasing departments is not which to pick – it's which to select. It is choosing the appropriate seal type, face material, elastomer, and support system for the fluid, pressure, temperature and regulatory requirements in which the pump is used. This is a comprehensive mechanical seals for pumps UK selection process guide including seal types, face materials, elastomer types, failure analysis, API 682 compliance and flush plan guidelines as well as a pump buyers checklist for UK industrial buyers. The principles of choosing seals outlined in this guide are applicable to the procurement of seals for chemical processing pumps on Teesside, offshore platform pumps in the North Sea, water treatment plants throughout England and even pharmaceutical manufacturing plants. If you are looking for both sealing and pumping solutions on your project, our technical article Centrifugal Pumps UK: Industrial Buyer’s Guide offers complementary advice on selecting the right pumps and system integration, which are often specified in conjunction with mechanical seal installations. How a Mechanical Seal Works: The Engineering Basics A mechanical seal is a clearance-free seal that prevents fluid leakage through a rotating shaft between the pump's casing and the rotating parts. The principal sealing interface are two precision-machined seal faces - one face that is attached to the rotating shaft and the other face that is stationary in the pump housing. The sealing interface is created by a controlled contact force between these faces, which is generated by springs causing the shaft to rotate with a minimum fluid escape. The sealing interface does not have a dry contact. The process fluid or barrier fluid forms a film on the seal faces which, during operation, lubricates the seal faces, and, at the same time, it is the reason why a seal cannot be operated without lubrication. If this lubricating layer is not present, the face temperature increases quickly, there is transfer of materials between the faces, and failure can occur within minutes. Hence, the selection of the pump mechanical seal should also consider the fluid's lubricating qualities, as well as its compatibility with the mechanical seal materials. Secondary sealing elements, which are usually O-rings or bellows, seal the clearance between the rotating and stationary elements and the shaft sleeve or housing bore. Both the face materials and the secondary sealing materials need to be chemically compatible with the process fluid and acceptable for the temperature range. Even if a seal is properly specified for the fluid and the wrong O-ring material is used for the temperature, it will fail. Types of Mechanical Seals Used in UK Industrial Pumps The first choice in the mechanical seals for pumps UK selection process is deciding on the type of seal to use. Every configuration has its own set of pros and cons in terms of ease of installation, reliability in tough environments and applicability in different regulatory settings. Single Mechanical Seals One mechanical seal has one set of seal faces. It works best with clean, non-hazardous process fluids. The major advantage is its simple design, low-cost and easy maintenance. Twin Mechanical Seal Double seals consist of two seal faces separated by a barrier fluid. Suitable for aggressive, toxic or hazardous process fluids. The main advantage is that no process fluid leaks to atmosphere. Mechanical Seal – Cartridge A cartridge seal is a pre-assembled, complete unit. It is good for all industrial applications and especially where maintenance is frequent. You get faster changeouts and less installation errors. Component Mechanical Seal Component seals are individual components that are assembled at site. Best for Custom Applications, OEM Replacements and Stock Pumps. The strength here is flexibility and lots of configuration options. Split Mechanical Seal Split seals are constructed of two parts and are mounted directly on the shaft. These are perfect for difficult to access installations or large shafts. You do not need to dismantle the pump or shaft at all. Bellows Seal (Metal) Instead of the spring and O…