The Malema M-VF Series is a safety excess flow valve designed for rapid automatic shut-off in case of line, hose, or fitting failure in gas and liquid systems. The valve protects personnel, equipment, and instrumentation by instantly stopping uncontrolled flow when a sudden surge or catastrophic line break occurs. The design operates entirely mechanically using a magnetic piston and venturi principle, eliminating the need for external power or electronic controls.

As flow increases beyond the preset threshold, the pressure differential across the piston overcomes the magnetic holding force, causing the piston to move rapidly into the shut-off position. Once system pressure equalizes after repair or shutdown, the valve automatically resets or can be manually reset depending on the configuration. Positive shut-off versions use an elastomer O-ring for bubble-tight sealing, while controlled-bleed versions allow automatic pressure equalization and reset functionality.

The M-VF Series is field adjustable and available in 1/8", 1/4", 3/8", 1/2", and 3/4" FNPT port sizes. Standard construction materials include 316 stainless steel and brass, with Viton or FFKM sealing options for compatibility with corrosive, toxic, radioactive, flammable, and high-purity media. Typical operating pressures reach up to 3000 psig with burst pressures up to 5000 psig depending on configuration.

Typical applications include gas analyzers, compressed gas systems, hydraulic lines, leak detection systems, sampling station protection, regulator protection, pollution control systems, and critical process installations requiring automatic protection against catastrophic flow failures.