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Technical Articles
January 19, 2016

Application

Vacuum Breaker Solves IBC Leak Problem

Beneficial for All Types of Storage Tanks

Cedar Grove, New Jersey USA & London, England — Intermediate Bulk Storage Containers (IBC’s) are commonly used in Europe to transport chemicals to companies which have minimal on-site requirements. Vacuum breakers are used on the tanks to prevent implosion during drainage, yet must not allow fumes to escape from the tank.

A leading U.K. manufacturer of 1000 litre IBC’s was experiencing problems with a spring-operated vacuum breaker. The spring design did not provide an effective seal and permitted fugitive emissions. The problem was most significant during transport, when sudden motion resulted in severe product leakage. Because the IBC manufacturer’s largest customer was primarily shipping a solution of 36% hydrochloric acid, the situation was critical.

The company tested a number of vacuum breakers, but was unsatisfied until finding a U.S. manufactured product from Plast-O-Matic Valves, Inc., based in Cedar Grove, New Jersey. The Plast-O-Matic True-Blue Vacuum Breaker, with a one-of-a-kind elastomeric diaphragm, was the only corrosion-resistant device able to meet the design criteria: Prevent tank implosion, yet remain sealed in all other situations regardless of motion or mounting position.

Patented Diaphragm

The diaphragm in the Plast-O-Matic True Blue vacuum breaker creates a bubble-tight seal, and sealing is unaffected by motion or direction. Installation at the highest location in a tank is recommended. After breaking a vacuum, the patented design causes the diaphragm to reposition and close in an identical location – a quality known as “positive repetitive sealing” – which means that it will prevent emissions and leaks throughout the life of the IBC.

To maintain the bubble-tight seal, the True-Blue Vacuum Breaker requires a minimum vacuum of at least 2″ Mercury (1 PSI) to open, which is well within the maximum negative pressure of 10″ of Mercury for an IBC. The flow rate of the vacuum breaker at 10″ of Mercury is 50 cubic feet of air per minute. For tanks that can withstand 20″ of Mercury, the flow rate is 95 cubic feet of air per minute. The breakers are manufactured in PVC, Polypropylene, Kynar® (PVDF) or PTFE and fulfill the need for corrosion resistance in chemical IBCs.

After reviewing case histories of the True Blue vacuum breaker in other tank applications, the IBC manufacturer tested and soon specified it into the product line. Since the switch, the emissions and leaks have been eliminated.

Useful in Many Tank Applications

Plast-O-Matic’s vacuum breakers are designed to protect many different types of tanks and storage vessels from collapse or structural damage during draining or pumping, as well as to prevent liquids from siphoning back into a tank. In one popular tank design, the breaker prevents liner separation; please click here for an application diagram in .pdf format. It is also used in large underground storage systems, where the True-Blue Vacuum Breaker is installed in an above-ground housing and connected to the tank or cavity via piping. The breaker is surprisingly compact, in pipe sizes from 1/2″ to 1″ NPT with total height ranging from 4.3″ to 5.1″. Maximum working pressure is 6,9 bar @ 24ºC (100 PSI @ 75ºF).

A special cap protects the Plast-O-Matic vacuum breaker by preventing foreign matter from entering the valve. It is also designed to minimize the “whistling” commonly associated with these devices. But for tank manufacturers and system designers – who know that vacuum conditions can wreak havoc – a little whistling is music to the ear!


In addition to vacuum breakers, typical Plast-O-Matic products associated with tanks and storage systems include check valves, relief valves, by-pass valves, gauge guards, level indicators and sight glasses.