Compact, self-closing vacuum breakers protect against hazards, damage and financial losses caused by vacuum. Designed to protect enclosed tanks from collapse or structural damage during draining. Eliminates siphoning of dangerous fluids. Prevents vacuum which can cause damage to sensitive instruments and filters. Insurance against replacement of damaged expensive equipment, avoids critical system downtime. Patented diaphragm design assures dependable, repetitive, bubbletight sealing in VBM. For corrosive or ultra-pure liquid applications. The VBM vacuum breakers have only one moving part - the patented self-sealing diaphragm, and this provides both design simplicity and maximum operating dependability. This normally-closed design seals in the identical location every time producing a very dependable, long-life seal. Maximum working pressure is 100 PSI at 75 degree F. Threaded connections are standard on all models. Socket end connectors are available on all sizes and materials except PTFE VB. Outlet connection is shipped with standard dust cap. Cap is removable for applications where pipe connection is desired due to location, potential hazard, etc. The outlet connection is identical to the connection on the system side of the valve. These Vacuum Breakers will begin to break a vacuum at approximately 2" of mercury (1.0 PSI or 0.07 Bar negative pressure). Full vacuum is 29" of mercury. For applications either draining or pumping from enclosed tanks, the tanks must be able to withstand much more than 2" of mercury of vacuum, as illustrated in the chart below. The chart is based upon a 3.5 times safety factor, and it clearly shows that as the rate of liquid flow leaving the tank increases, the resulting vacuum in the tank also increases.
