Piping systems play an essential role in worldwide infrastructure. These systems have been around for decades. Installing a piping system is not an easy task. If components like flanges are not properly selected and lack the right flange connection, corrosion and leaks could occur. When corrosion and leaks occur, a breakdown in the assembly can happen and cause a monstrous mess.
Below are few possible causes of corrosion and how to avoid it.
There are a lot of things that may put stress on the bolts. Vibrations that occur during the normal operating conditions tend to bolt movement leading to corrosion and leakage. Although the vibrations happen by normal operations, it is still something that you can avoid to a degree. Tightening the bolts seems to be an obvious solution, but you need to consider how often you need to check them.
Temperature also plays a part in how well bolts connect and whether they are successful in preventing leaks. Temperature fluctuations happen during an increase in temperature and cause bolts to become loose and not seal properly. Minimizing temperature fluctuation when possible is ideal.
Due to the usual operating procedures for high-stress environments, you can expect to tighten and check bolts due to temperature fluctuations. When bolts are tightened and checked, and the issue does not seem to be remedied, you may be dealing with another issue besides expected wear from normal operating procedures.
The temperature of the product (inside a tube heat exchanger and shell for example) can vary. However, the distortion caused by the rapid change from cool to hot solutions is inevitable in few cases. If this is the case, it is essential to ensure all parts of the exchanger are designed to account for temperature distortion. Alloys are considered carefully by engineers for this very reason.
If you want to determine your requirements, special considerations need to be made regarding the flange dimensions. Next, determine the temperature of a high load area within the tube and a random area on the shell side. Calculate the difference between the tube side outlet and inlet and the difference between the random area on the tube side and the shell side.
Many things can produce stress on the bolts of the flange connections, but one, in particular, is the stress on both sides of the flange assembly point. When circumstances happen to cause one side to be tightened more than the other, the gasket becomes damaged, resulting in leakage. It can happen by improper bolting procedures during the initial installation.
Sometimes these pipes are assembled in small spaces, making it hard to reach specific bold to tighten them. It can lead to some bolts being properly tightened while the others are not as tight. The same amount of pressure needs to be applied to all bolts. It helps to hold the gasket securely in place due to corrosion and leakage.
It may not be easy to spot imperfections. Sometimes warped surfaces can lead to improper installation. If the flange face is warped or has other deformities, improper seals tend to occur. While the issue may not cause direct interruptions in the flow, it can cause corrosion and leaks. Just like other pipe fittings, flanges usually need to work in conditions free from any defects to work properly. Some of the defects are easier to notice than others. A welded face may be harder to recognize, and it could easily get overlooked. Flange face re-machining is a common remedy in these cases.
Need Of Additional Hardware
A recurring problem in a tube and shell heat exchanger, bolts need to stay secure, despite efforts to tighten them using the proven techniques. Even after hydraulic tensioning and hot torquing, the bolts would loosen and cause problematic leaking in the plant.
Researchers identified two problems: gasket scuffing and excessive bolt load. The excessive bolt load happens due to temperature differentials. If you want to combat this issue, install disc spring washers before you replace the bolts. They found that these were more capable of handling the load to the bolts without allowing flange deformation in most cases.
The second issue of gasket scuffing was likely due to movement during operation and caused enough damage to the gasket, that even with adequate bolt tightness, it would continue to leak. The gasket needs replacement, but the problem also needs to be addressed so the new gasket would not also fall into disrepair. If you want to avoid this, a weld ring consists of two separate halves of the gasket ring welded together to contain the gasket material and prevent any deformation.
If you are experiencing gasket leaks in your tube and shell heat exchangers, it could indicate that something is amiss in your equipment. The staff at Texas Flange are happy to help point you in the right direction and recommend the right sourcing for your assembly hardware needs along with the usual flange and fitting products we provide our customers every day.