The 4 most common mechanical seal types and variations
Mechanical seal types vary in design, setup, and how they disperse the hydraulic forces acting at their faces.
The most common design types are Rubber Diaphragm, Rubber Bellows, O-Ring Mounted & PTFE Wedge. Whilst, other common variations include balanced and unbalanced, pusher and non-pusher, single spring and multi-spring.
Below we take a deeper look at each of these mechanical seal design types, whilst also covering the variations mentioned.
TYPE 1: Rubber Diaphragm
These highly effective seals are widely utilised in pumps, mixers, agitators, compressors and other rotary shaft equipment.
TYPE 2: Rubber Bellows
Ideal for equipment with limited space, they can also be used where a previous seal has caused shaft damage.
TYPE 3: O-Ring Mounted
These seals offer the capability to align with the rotating shaft to ensure efficient productivity and stop misalignment.
TYPE 4: PTFE Wedge
Designed for use where expensive and corrosive liquids are being processed, especially for extremely corrosive fluid applications.
The common mechanical seal variations
In addition to the four primary types of mechanical seals it should be noted that some have sub-types that enable to seal to perform under differing environments such as pressure, temperature or the type of media that is being pumped.
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Balanced & Unbalanced
Find out moreSeals are available as balanced, for high pressure, and unbalanced, for low pressure, with both having advantages and disadvantages.
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Pusher & Non-Pusher
Find out moreAnother condsideration is if a pusher seal, for low temperatures, or non-pusher seals, for high temperatures, is best suited for the job.
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Single & Multi-Spring
Find out moreSome seals come with a single spring, however, there are times when a mutli-spring seal is required, when handling hazadous fluids.
Some mechanical seal variants can go by different names to the ones listed above. There can often be some overlap in how various manufacturers might name them so please be aware of possible confusion.
Our Promise
Mechanical seals are a complex topic and the above information has been provided as an overview of the subject. All of our information is provided in good faith and should be used as a guide. If you have any queries please get in touch to speak to an expert, we will be happy to help.
The basics of Mechanical Seals
Identifying, buying and replacing mechanical seals can be complicated if you don't know what you are doing. Find out how mechanical seals work, the components in them and why they should be used.
Our Mechanical Seals range
We can supply replacement seals for most major manufacturers: Eagle Burgmann, John Crane, Roten/Uniten, AES, Alfa Laval, Grundfos, MTU, PAC-Seal, US Seal and more.
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Use toolOur Mechanical Seal Idenitifcation tool can help you indentify the seal you need by selecting the key design features.
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View guideOur Mechanical Seals Materials Guide can tell you which material will give you the perfect seal.
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Check Chemical Compatibility
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