Safety Excess Flow Valves
Malema produces two types of safety excess flow valves: the M-VF and the M-XF series.
The M-VF is offered with port sizes ranging from 1/8" to 3/4" and designed for flow rates up to 20 gpm (water) and 130 scfm (air). The M-XF series is much larger with port sizes ranging from 3/4" up to 10" and designed for flow rates up to 2500 gpm (water) and 10,000 scfm (air).
M-VF Excess Flow Valve
The M-VF is engineered for fast automatic shut-off in case of line, hose, or fitting failure protecting plant, personnel, and instruments. As fluid (liquid or gas) enters the valve, the pressure differential across the pison creates a venturi effect, accelerating the flow through the valve. When the differential excees the magnetic attraction between the piston magnet and the adjusting screw magnet, the piston travels instantaneously over the valve seat, thereby shutting off the flow. Adjustment of this valve (setting the flow set-point) is achieved by turning the adjusting screw.
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The M-VF series (pictured on left) has the option of intrinsic reset (MRVO). In other words, after the excessive fluid flow has shut the valve, you can reset the valve to its previous trip point by actuating the 1/4 turn reset valve. The M-VF MRVO comes with a ball lock pin interlock to prevent inadvertent opening of the reset valve. (Patent No. 5,445,184) |
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M-VF Excess Flow Valve |
| Operating Range: 1/8": Air: 0.175 to 5 scfm, Water: 0.0026 to 0.8 gpm; 1/4": Air: 0.1225 to 35 scfm, Water: 0.026 to 3.5 gpm; 3/8": Air: 3 to 60 scfm, Water: 0.1 to 4 gpm; 1/2": Air: 5 to 75 scfm, Water: 0.5 to 10 gpm; 3/4": Air: 15 to 130 scfm, Water: 1 to 20 gpm; |
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| Port Sizes 1/8" or 1/4" FNPT ports |
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| Body Materials Brass or 316SS |
The M-XF is also engineered for fast automatic shut-off in case of line, hose, or fitting failure protecting plant, personnel, and instruments. As fluid enters the valve, it flows through the orifice to the outlet. The orifice and tapered piston create a venturi effect, accelerating the flow through the valve. The pressure differential has to offset the spring loading of the piston to shut off the valve. It can be disasembled for repair or inspection without being removed from the pipe line. The M-XF is:
- Extremely field adjustable.
- Broad adjustable range.
- Meets OSHA requirements for safety shut off valves.
- Operates effectively with all fluids, liquids, and gases.
- Customer request seals and gaskets for best media compatibility.
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M-XF Excess Flow Valve |
| Operating Range 3/4": Air: 0.5 to 180 scfm, Water: 0.1 to 15 gpm. 1": Air: 2 to 400 scfm, Water: 0.5 to 25 gpm. 1 1/2": Air: 4 to 800 scfm, Water: 1 to 50 gpm. 2": Air: 8 to 1,500 scfm, Water: 2 to 90 gpm. 3": Air: 20 to 4,200 scfm, Water: 5 to 190 gpm. 4": Air: 40 to 5,800 scfm, Water: 10 to 350 gpm. 6": Air: 60 to 13,000 scfm, Water: 15 to 850 gpm. 8": Air: 72 to 18,000 scfm, Water: 18 to 1,450 gpm. 10": Air: 80 to 40,000 scfm, Water: 20 to 2,500 gpm. |
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| Port Sizes 3/4", 1", 1 1/2", 2", 3", 4", 6", 8", or 10" FNPT, Flanged, or Socket Weld ports. |
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| Body Materials Bronze, Cast Iron, Cast Steel, Forged Steel, or 316SS. |