Using a Universal Ball Dome Fitting on Your Chemical Storage Tank

Universal ball dome fittings, or UBD fittings, are a type of tank fitting that has a moveable ball inside to allow angular adjustments. UBD fittings can only be installed on the dome of the chemical storage tank, because they aren’t considered leak-tight. The dome fitting has a compression nut that locks down the ball after you install the flange or bulkhead, allowing connections at angles up to 24 degrees. 

The self-aligning UBD fittings can be installed on the dome of a Poly Processing storage tank to give you more options for fitting placement. UBD fittings are an excellent choice for our double-wall SAFE-Tanks®, vertical tanks, or IMFO® Tanks. 

Let’s take a look at the uses for these types of fittings and their advantages.

Advantages of a Universal Ball Dome Fitting

In a situation where vertical plumbing is needed, it is usually necessary to install a fitting on one of the molded-in boxes or runway flats on the dome of the tank. This ensures that the connection can be mated vertically to plumbing systems. When the fitting has to be mounted on the dome, the UBD may be the right choice. The ball inside the fitting rotates up to 24 degrees, so the fitting can be installed directly on the dome, allowing for vertical connections to your piping systems.

Whether you choose a bulkhead or flange style UBD is largely your preference. Poly Processing offers both styles. Poly Processing’s UBD fitting standard sizes are 1” to 4” flange style, or 1” to 3” in the bulkhead style.

When Are Universal Ball Dome Fittings Most Useful?

In cases where reverse float gauges are installed, you want to make sure the fitting coming out of the top of the tank is vertical. In some cases, customers choose the dome portion of the top of the tank for the reverse float gauge installation.

The UBD fittings work well in this application and save you the cost of having a custom welded fitting. Custom welded fittings are expensive because they are hand-welded to the angle of the dome of the tank — and in some cases they can change alignment over time due to fluctuations in temperatures of the tank. These fluctuations push the fitting out of calibration.

A UBD fitting usually has a nipple inserted into the fitting end and either a male thread or female slip pipe connection for the on site plumbing installation. Poly Processing can install a mating flange to the pipe, giving you the opportunity to make flanged connections out of the top of the tank.

A universal ball dome fitting can be used in almost every storage application, but they are especially useful in situations where ultrasonic devices are used. Often, people will install large (sometimes 6 inch) made-level fittings to install the ultrasonic level sensor from, which isn’t necessary. 

The UBD fittings have the adjustable ball and the ultrasonic level sensors typically have 2 connections that fit right into the ball. This gives you a vertical ultrasonic level sensor at a much more competitive cost.

The universal ball dome fitting is also helpful in internal and external combination fill lines when you would like to install a fitting on the dome. The UBD fittings allow the downpipe and fill line to attach to the top of the tank vertically.

This is one of the many innovations Poly Processing offers to enhance the value of the chemical storage system and make it cost effective for our customers. To learn more, reach out to a chemical storage expert.