Introduction
If you are new to the industry, you might not know the difference between Ring Type Joint and Raised Face. The difference is actually pretty simple and refers to the type of flange that you need to use when making your join.
In this post, we will compare RTJ and RF so that you understand the differences more completely. Both types of joins are useful, but each has their own advantages and disadvantages. This post should give you more clarity and help you to identify what projects the different flanges are best suited for.
Differences: Ring Type Joint vs Raised Face
Raised Face
This is the type most commonly found in processing plants. When you see it, you will be able to recognise it straight away. In this model, the surfaces to attach the gasket to are raised. The bolting circle will always be lower than the gasket surfaces.
The advantages are :
- You can use a wider range of gaskets – from spiral wound types to flat ring sheet types.
- As the surface is raised, it is more easily accessible. Replacing a worn gasket is thus a lot easier.
- This design enables more pressure to be concentrated onto a smaller gasket area. This, in turn, helps the joint handle pressure containment better.
- It is also useful when you need better separation between the two flanges being joined.
Ring-Type Joint
These are more commonly used in applications where either high pressure or high temperature is an issue. These are Class 600 or more flanges or where temperatures typically exceed 427° Centigrade.
These flanges can be identified because they have grooves that are cut into their service. A metallic gasket is fitted into these grooves and then compressed to create a solid seal. The gasket is somewhat mangled in the process but fits into space perfectly.
The advantages are:
- Metal to metal seals is made possible. These are a lot stronger and will withstand high heat, pressure and corrosion caused by chemicals.
- The grooves allow for a tighter fit and can be useful in situations where space is an issue.
- Depending on the type of gasket used, the faces may be in direct contact with one another.
- The gasket is not going to compress any more once it has been tightened. This makes it more resistant to movement and vibration.
- You have a reduced range of options when it comes to the type of gaskets that you can use. However, if you choose the right type for the job, the seal is highly reliable and strong.
Conclusion
As you can see, there are advantages to both types of flanges. You need to use the best design option for your project. It just pays to remember that you should always use the right connections for the best join possible.
Using an RF connection on an RTJ is a recipe for disaster. It may hold initially, but something is bound to go wrong further down the line with this kind of tinkering.
