A ring type joint is a specialised gasket, designed to be used with flanges that have grooves in them. The advantage of this type of gasket is that it is made of metal and so creates a seal that is very strong and reliable.
It will withstand the pressure of up to 1500 Bars and temperatures of up to 1000° Centigrade. Also, it is resistant to chemical corrosion. The gasket is fitted into the groove. The two faces are then bolted together. As the ring type joint is compressed, it creates a solid seal.
They come in a range of different metals, from soft iron to stainless steel. It is essential to choose the right type of metal and shape for the job at hand.
4 Standard Types of RTJ
There are four basic types that you will need to choose from. These types are based on the shape of the ring and the flange groove that it will fit into. You will need to select the right shape to fit the groove, but also consider the type of metal as well.
The metal that the gasket is made of is softer than the flanges themselves. This is to prevent damage to the flanges and to ensure that the seal is good.
R Oval RTJ
If you were to take a cross-section of this model, it would be an oval shape. It is designed to fit the standard flange. The oval shape is the first design to have been made.
R Octagonal RTJ
These will also fit a standard flange, but a cross-section of this one would reveal a hexagonal shape. This provides a tighter seal than the oval models.
These are interchangeable with the previous models. The RX models, however, are wider than the previous type. This means that the two faces being joined will not be right up against one another. This is useful when compensating for vibrations, shock loadings, etc.
They can seal themselves and can be used up to a Class 5000 and up to 700 Bars of pressure.
These cannot be interchanged with the other two types and must be used with BX flanges of the API type. It is capable of handling a lot more pressure. They can handle up to 1500 Bars of pressure.
They can handle more pressure because there is a small hole that is drilled into the to ring itself. This is what makes pressure equalisation on either side of the join possible.
The ring is slightly bigger than the groove that is made for. This is to create a high-pressure seal. The downside is that more careful fitting is required. You need to ensure that the separation between the two joined piece is nice and even all the way around.
This can handle a class rating of 2000 to 20 000 PSI.
Ring-type joints provide strong seals that are useful in high-demand situations. With the right model, you can be sure that the seal will be reliable and will hold well. There are also more customized types of Ring Type Joint, but the standard ones are normally more than adequate.
Read the next article: Difference between Ring Type Joint and Raised Face