Can I put large fittings in my tank, 4″ and larger?
When large compression style tank fittings are installed into polyethylene tanks, you need to have a flat surface available to mount the fitting on that will allow it to seat completely around the entire circumference of the fitting. If you try to install a large compression style fitting onto a curved surface, the fitting cannot seal and you will have leaks. In addition, if you try to tighten the fitting down in an attempt to get a good seal and you “flatten out” the tank wall in the process, you will create a stress area and eventually cause a stress crack in that area. So, how can a large fitting be installed in a small diameter tank? The answer is thermopneumatically welding the fittings into the tank. We can weld couplings or flanges into any tank in sizes from Â½” up to 48″ and larger, depending on the application. Ask your sales representative for assistance in designing your process tank and fitting configuration.
Source: FAQs - Peabody