It’s essential when working with specific applications and systems that you use the correct gaskets and seals in order to prevent leaks and contamination – and there are numerous types, sizes, and designs to choose from.
Two such types of seals come in the form of gaskets and packing, with both seals serving the same ultimate purpose, to prevent leaks; however, they have very distinct forms and functions, and are only suitable for specific applications.
In this post, we look at the difference between gaskets and packing in more detail, as well as their use and benefits, allowing you to make the most informed decision for your application, helping you to achieve optimal performance.
Gasket vs packing
When we look at gasket and packing differences, we start by examining the function of each, for example:
A gasket seal is static in its design and is placed in the space of two mating surfaces and then compressed. These surfaces are typically flat.
This mechanical seal is used to fill the space between two surfaces, under compression, to prevent leaks in mechanical systems.
Gasket seals can also be used to fill irregularities, and can be found in a range of material types such as cork, rubber, silicone, metal, nitrile, plastic, etc.
If you’re looking for a gasket seal that provides strong chemical resistance, opt for gasket materials Viton or EPDM, for high temperatures look for graphite gaskets and potentially silicone, for example.
In comparison, packing seals come in a range of flexible materials that can be used in moving components, with packing typically used as a dynamic seal. Used to fill the gaps or spaces between surfaces, packing seals consist of braided fibres, such as graphite or PTFE, that are then used alongside a sealing agent (braided, twisted, or consolidated) to provide a secure seal in moving parts.
For high chemical resistance, opt for PTFE packing seals or graphite, for high temperature applications opt for expanded graphite.
(As an aside, o rings are also popular sealing products that are suitable for static and dynamic situations and equipment, seated within a groove and then compressed between the mating surfaces to provide a seal, to find out more visit our website and check out our range of o ring options.)
When to use a gasket vs packing
Gaskets are typically used in:
- Pipework
- Manholes/access hatches
- Heat exchangers
Packing is suitable for:
- Pumps
- Valves
- Compressors
- Mixers
Gasket or packing – which should you use?
Depending on your application and also the environment in which the gaskets and seals will be exposed to will depend on which sealing type you opt for.
For example, gaskets are available in a range of material types such as rubber, PTFE (offering high chemical resistance), spiral wound, and kamprofiles, with spiral wound gaskets in particular most suitable for applications involving extreme pressure and temperature ranges due to their incredible resilience.
Braided compression packings are popular packing seals that are used in rotary or reciprocating motion applications, as they are able to handle high speeds and medium pressure. They are also adjustable, tolerant of shaft runout, and they can withstand high-temperature applications with ease. However, braided compression packing does require regular tightening and can increase wear.
It’s also important to note that packing seals are not suitable for flat surfaces. And you will also need to use a material for both packing and gasket seals that is compatible with the application where it will be used. This is essential, as you must avoid adverse chemical reactions, corrosion, and safety hazards.
You may also find that gaskets are less expensive compared to packing seals, however your decision should not solely be based on price. You must also consider material compatibility, environment, application requirements, pressure, temperature ranges, and more.
Gland packing vs gasket
A gland packing gasket is often used when there is a requirement to prevent leaks of gland steam in steam turbines.
Gland packing is the most suitable choice in this scenario instead of a gasket due to the dynamic application and rotary motion, which packing is more suited to.
Gland packing is also more flexible and can be adjusted with ease for this particular application, compared to gaskets, which prefer a flat and static surface.
Gaskets and seals
For all two common terms when sealing, both gaskets and packings are each engineered for different and specific conditions.
It’s important to make the most appropriate choice for your application, as wrong sealing choices can lead to leaks and damage to the equipment.
If you’re unsure or you would like further information, please contact the team at Specialist Sealing Products today. We’d be more than happy to help.
Providing our customers with a range of sealing solutions, including gaskets and packing contact us today on 01535 274 776 or email us at: sales@specialistsealingproducts.co.uk
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