ZM-R

Blanketing Valve low pressure reducing valve

single-stage pressure reduction possible within a high-pressure range
large diaphragm area to increase the closing force
all function-relevant and product-contacting parts are made of stainless steel or Hastelloy
simple adjustment of set pressure (within the spring range)
any mounting position (taking the set pressure into account)
no external energy supply needed
high flow capacity reduces costs through the use of smaller valves
valve pallet is guided inside the housing to protect against harsh weather conditions, e.g., freezing of the valve pallet in extreme cold
reduction within the vacuum range is possible
high precision
can be used in explosion hazardous areas
sturdy housing design (PN 16)
maintenance-friendly design

Function and Description

The blanketing valve type ZM-R is a highly developed low pressure reducing valve. This valve is typically used to inert or blanket tanks, vessels, or other process systems with nitrogen or other blanketing gases by controlling the tank pressure to ist desired value. High nitrogen or blanketing gas supply pressures up to 16 bar / 232 psi are safely reduced down to only a few mbar / inch W.C..

The ZM-R low pressure reducing valve is a direct acting, one stage pressure control device. It is designed as a diaphragm controlled, spring-loaded proportional acting valve. The valve controls the tank pressure by increasing flow as the tank pressure drops. This means that the mass flow through the valve depends on the pressure differential of the set pressure to the actual tank pressure. When the actual tank pressure reaches the set pressure, the control unit closes, and there is no flow.

At the control diaphragm, (which can be made from PTFE or Viton), the tank pressure (P₂) is balanced with the adjustment spring and the supply pressure (P₁). In a depressurized tank, the adjustment spring holds the valve pallet in the fully open position. As the tank pressure increases, the valve pallet moves toward the seat, and the mass flow is reduced. When the desired tank pressure is reached, the valve will close.

If the tank pressure decreases, the valve will open. If the system is operated in a vacuum mode, vacuum pressures down to -200 mbar /-80 inch W.C. (relative pressure) can be achieved.

Design Types and Specifications

Two different designs are available:

Blanketing valve for overpressure, standard design	ZM-R –
Blanketing valve for vacuum, standard design	ZM-R / N

Other special devices can be supplied on request
For in-line valves any back pressure, which will influence the set pressure and opening characteristics, has to be taken into account.

Settings

Supply pressure:		+16 bar
		+6424 inch W.C.
Set pressure for overpressure function:		+500 mbar
		+200 inch W.C.
Set pressure for vacuum function:		-200 mbar
		-80 inch W.C.