{"id":13195,"date":"2026-09-16T16:00:00","date_gmt":"2026-09-16T14:00:00","guid":{"rendered":"https:\/\/www.lidering.com\/what-is-a-mechanical-seal\/"},"modified":"2026-09-16T16:02:18","modified_gmt":"2026-09-16T14:02:18","slug":"what-is-a-mechanical-seal-working-principle-types","status":"publish","type":"post","link":"https:\/\/www.lidering.com\/en\/what-is-a-mechanical-seal-working-principle-types\/","title":{"rendered":"Mechanical seals: operation, types and selection for industry"},"content":{"rendered":"

Mechanical seals are key elements for optimal sealing in industrial machinery that requires fluid circulation. Equipment like pumps or compressors are prone to liquid leaks that reduce performance and eventually lead to breakdowns over time. Therefore, it\u2019s essential to choose the right mechanical seal to boost installation reliability and reduce unexpected maintenance downtime.<\/p>\n

At Lidering, we’ve been studying the behaviour of mechanical seals for years to meet the most demanding needs of our clients. In this article, we’ll explain in detail what a mechanical seal is, how it works, what alternatives exist, and which one best suits each type of use.<\/p>\n

What is a mechanical seal and how does it work?<\/h2>\n

\"Close-up<\/p>\n

A mechanical seal is a dynamic element that seals the leakage point between two parts that move relative to each other. In the case of pumps, for example, the shaft spins pulling an impeller while the casing remains fixed, so the mechanical seal would be placed between the two parts to prevent fluid from leaking out.<\/p>\n

The system consists of two seal faces: one stationary, attached to the equipment structure, and the other rotating, mounted on the shaft. Both stay in constant contact by a spring that compensates for small movements and vibrations in the system. Each face seals statically with its respective component (in this case, the structure and the shaft) using an elastomer, which completes the seal.<\/p>\n

Comparison between mechanical seals and other sealing elements<\/h2>\n

Mechanical seals are not the only solution for sealing rotating equipment, but they have been the most widely used for decades. The most well-known alternative is gland packing, which, although it generates pressure between the material and the rotating shaft, needs a small, controlled leak to operate with some lubrication and avoid potential damage.<\/p>\n

For decades, mechanical seals have been replacing gland packing in most industrial uses as they provide a much more effective seal and significantly reduce energy consumption due to friction.<\/p>\n

Below is a table comparing the three most well-known sealing systems along with their key features:<\/p>\n\n\n\n\n\n\n
Sealing system<\/span><\/b><\/td>\nSealing level<\/span><\/b><\/td>\nNeeds controlled leak<\/span><\/b><\/td>\nMaintenance<\/span><\/b><\/td>\n<\/tr>\n
Mechanical seal<\/span><\/td>\nPractically total<\/span><\/td>\nNo<\/span><\/td>\nLow, if well aligned<\/span><\/td>\n<\/tr>\n
Gland packing<\/span><\/td>\nPartial<\/span><\/td>\nYes<\/span><\/td>\nFrequent, due to wear<\/span><\/td>\n<\/tr>\n
Lip seal<\/span><\/td>\nHigh, but only with low pressures and temperatures<\/span><\/td>\nNo, but the lip does need lubrication<\/span><\/td>\nIt should be completely replaced after each disassembly.<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Types of mechanical according to design and materials<\/h2>\n

\"Selection<\/p>\n

There is no “universal” mechanical seal that fits all types of uses. The design and suitable materials will vary depending on the equipment operating pressure, temperature and fluid. Therefore, it’s essential to choose the right combination to avoid early breakdowns and extend the lifespan of the installation. Next, we’ll briefly explain the most common alternatives:<\/p>\n