MAG-A & MAG-G - Differential pressure gauges for air and gas

Description

The MAG-A and MAG-G series are Magnehelic differential pressure gauges designed for accurate, reliable, and economical measurement of low air and non-corrosive gas pressures. These devices use a frictionless diaphragm-actuated mechanism that transfers pressure variations to an indicating pointer through a magnetic linkage system. This construction ensures high sensitivity, long-term stability, and immunity to issues typical of fluid-based manometers, such as evaporation, freezing, toxic exposure, or leveling requirements.

These gauges are widely used in industrial combustion systems and general process control environments. Typical applications include measuring pressure drops across orifice plates, monitoring filters, checking blower pressure, assessing furnace draft, and providing general air or natural gas pressure indication. The design resists shock, vibration, and overpressure, with a relief plug that opens at approximately 1.72 bar in standard models.

The instruments feature a 101.6 mm diameter dial, die-cast aluminum housing with an acrylic cover, and duplicate pressure taps (1/8″ NPT) located on both the side and back. They operate within a temperature range of –7°C to 60°C, and offer an accuracy of ±2% of full scale at 21.1°C. Models are available with various scales, including both absolute and double scale versions, from 50 mmH₂O up to 350 cmH₂O.

Installation requires positioning the diaphragm vertically for optimal accuracy. The gauges can be surface-mounted or flush-mounted, and long sensing lines can be used without affecting measurement precision, although response time may slightly increase. Zero calibration is performed via an external adjustment screw when both taps are vented to atmosphere.

Maintenance is minimal: no lubrication or regular servicing is required beyond occasional re-zeroing. The devices comply with UNI EN 746-2:2010 and meet the safety requirements of the Machinery Directive 2006/42/CE, with additional conformity to UNI EN ISO 9001 standards.