ULTRAC MVZ Zero Manifold Valve
Applications
The ULTRAC Zero Manifold Valve (MVZ) is designed for use with standard and purge-type flow transmitters and indicating gauges. Many low-pressure d.p. transmitters are offset during the zero adjustment setting by the effects of process static pressure. Some instruments may indicate an output change of as much at +/-2% with a 32" w.c. change in static pressure.
Purging flow and pressure transmitters designed to measure low pressures may pick up small pressure losses due to the purge flow in the process connecting tubing. These small pressures may be zeroed out if they do not exceed the zero-compensation adjustment range of the transmitter.
However, if these tubing pressure losses are significantly high relative to the full span of the transmitter, they will cause a loading effect on the measured signal and a resultant insensitivity to process pressure changes.
The MVZ valve provides a means of equalizing pressures between high and low differential pressure ports for transmitter zero adjustment purposes while process static pressures are applied. The zero adjustment is therefore static-pressure compensated, resulting in a more accurate measurement.
Description
The ULTRAC MVZ is a factory modified ball valve with elastic seat and stainless steel ball. The valve is ported and fitted to match purge-type transmitter air flows. The units are available in brass or stainless steel. An indicator plate is fitted which clearly indicates ZERO and RUN positions. Tubing fittings equal to the valve order size are installed.
Specifications for MVZ-BR
BODY: Brass SEALS: Buna-N TEMPERATURE: -40°F to +200°F
Specifications for MVZ-SS
BODY: 316 Stainless Steel SEALS: Teflon/Viton TEMPERATURE: -40°F to +400°F
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