When it comes to manway gaskets, we want to keep things simple, introducing them as the small sealing ring found in hatches/openings that are constructed for large tanks. Openings which give people access to the inside of the aforementioned tanks and vessels.
The types of tanks we mean include the large tankers which are used for filling and storing liquids — those used within the food, beverage, dairy and pharmaceutical industries.
In this post we’re going to look at manway gaskets in a little more depth, finding out just what they can offer, why they are used and some of the materials they are made from.
Manway Gaskets or Manway Seals
Manway Gaskets can also be known as Manway Seals or in the brewing industry, in particular, Brewery Door Seals (as they’re a seal which is used heavily in this industry, sealing the doors to the actual brewing tanks).
These seals/gaskets can be found in:
- the food and beverage sectors
- working farms and large dairy farms
- certain areas of the pharmaceutical industry
Acting as an industry standard when it comes to keeping liquids and fillings stored safely inside while still allowing for access when required.
These large tanks and containers can be used to store many different types of fluids and materials and manway gaskets can provide the seal for products such as sugar, flour, oils, chemicals, and beverages.
Of course, these small hatches and entranceways need to be properly sealed to stop anything like the above from getting out, making manway seals of vital importance.
In this instance, you also need a seal that helps with Non-Accident Releases (NARs), and you need a seal that avoids over-torquing, re-torquing, and ultimately general manway damage.
Materials used for manway seals
Development of manway seals has come a long way over the years with new, tried and tested materials being used reviewing what materials offer the best solutions for businesses who have experience of NARs.
Most manlid door seals are now made with rubber, as it has been reported that hinged and bolt manways have, in the past, been the number one cause of Non-Accident Releases, which has had dramatic consequences for the businesses and individuals involved.
For example, elastomeric gaskets are made from rubber materials including, Buna N, Viton, Nitrile, SBR, and EPDM.
Food grade silicone and EPDM produced gaskets are the most common in the market. Mainly due to their elasticity, meaning they don’t compress and they’re able to deform even under the lightest of loads.
However, silicone gaskets can withstand higher temperatures and are resistant to fungal attacks within tanks. But they do have a poor tolerance to steam.
EPDM manufactured gaskets have a lower upper-temperature limit, but these seals are resistant to steam, as well as ozone, acids, and alkalis.
Specialist Sealing Products (SSP) offer several manway door seals for access doors, vessels, tanks and more. Vulcanizing seals to any dimension, size, and section. From round oval to rectangular we can supply seals in a range of materials all dependant on specific requirements and range of fluid content.
Role of a Manway Seal
Large tankers and vessels etc, are all constructed with a manway so that someone can ultimately get into these big tanks and fix any problems inside, as well as clean them out!
Manways must be large enough for a person to be able to fit through and are most commonly found at the bottom of a tank. Each manway seal is different as the material and type of gasket used will all depend on the contents of what’s inside the container, i.e., the pressure and the temperature of the liquid contained inside.
Every manway needs a gasket/seal to stop it from leaking, and ideally these should be soft, can resist taking on a compression set and where appropriate must be of a food-grade standard to avoid any contamination.
If manway gaskets aren’t fitted correctly or they become broken, it can result in a full door gasket failure and pose significant safety risks as well as being extremely costly to repair.
SSP uses the latest technology to help overcome such potential issues, designing seals to achieve successful gasket sealing through entire cycles – making our manlid door seals more reliable, sustainable and cost-effective.
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