MAGNEHELIC®, PHOTOHELIC®, MINIHELIC®, and DIGIHELIC®
Differential Pressure Gauges/Controller

MAGNEHELIC®	PHOTOHELIC®
MINIHELIC II®	DIGIHELIC®

• Measure and control both positive and negative low air or gas pressures
• Provide an ideal way of monitoring and controlling the positive pressure differential required for cleanrooms
• Enable you to meet FED STD 209E regarding cleanroom pressure
• Ideal for measuring differential pressure in gloveboxes and air flow in exhaust hoods
• MAGNEHELIC® Principle ensures wear-free accuracy within 2% of full scale
• Resists shock and vibration
• Available in a number of pressure gauges to suit a wide range of applications, such as gauging air filters, monitoring air conditioning systems, and measuring static air pressure and air vehicles

If your facility incorporates a laminar flow cleanroom, these MAGNEHELIC® and PHOTOHELIC® differential pressure gauges can help you maintain the positive pressure necessary to block inrushing contaminants that can damage sensitive materials and operations. In doing so, they also help to meet the requirements and recommendations set forth in FED STD 209E which specifies that a minimum positive pressure of 0.05" (1 mm) of water differential be maintained between the cleanroom and adjacent areas.

Chatterless, Wear-Free Accuracy
These gauges incorporate an exclusive MAGNEHELIC® Principle that eliminates wear, backlash, and hysteresis. The result is a remarkably high standard of accurate, dependable gauge performance at a modest price.

This MAGNEHELIC® Principle is a method of transmitting the effects of changes in air pressure from a diaphragm to an indicating pointer—by means of magnetic linkage and without the use of gears or other direct mechanical linkages. This system avoids wear and physical contact, which might destroy the accuracy and sensitivity of the instrument. It delivers accuracy to within 2% of full scale.

This principle offers numerous advantages over other gauges. Because it uses no fluid, it eliminates evaporation, freezing, or toxicity problems. It also ensures inertia-free, drift-free pointer movement and offers unusually high resistance to shock and vibration. These gauges are also unharmed by pressure surges up to 15 psig and by ambient temperature fluctuations between 20 and 140 degrees F (-7 and 60°C) .

Both MAGNEHELIC® and PHOTOHELIC® gauges feature easy-to-read 4" (102 mm) dials that quickly provide gas pressures—positive, negative or differential. Because operation does not depend on gravity, you can either face- or flush-mount them in any position. Gauges can also be mounted on panels either inside or outside of the cleanroom; if mounted inside, the low pressure ports of the room pressure gauges can be connected together, and a single tube routed to outside the room.

Versatile Applications
Use the MAGNEHELIC® gauges (range of .25-4.0" WC) to determine positive pressure differentials between the cleanroom and adjacent areas. MAGNEHELIC® gauges can also be used to measure pressure drops across pre-filters and absolute filters.

A PHOTOHELIC® gauge/switch can also be used to control makeup or exhaust air dampers in order to maintain the room pressure within prescribed limits. All gauges can be mounted on a control panel. Gauge calibration is accomplished between room readings. In this application the PHOTOHELIC® gauge serves as the “master” gauge.

These units can also be used to check air filters, to sense static pressure or to measure air velocity and volume.

The MAGNEHELIC® Pressure Gauge

PHOTOHELIC® Pressure Control

Minihelic II® Differential Pressure Gauges

With removable lens and rear housing, the gauge may be easily serviced at minimum cost. With the housing molded from mineral and glass-filled nylon and the lens molded from polycarbonate, the gauge will with stand rough use and exposure as well as high total pressure. The 5% accuracy and low cost of the Minihelic®II gauge make it well suited for a wide variety of OEM and user applications.

DIGIHELIC® Differential Pressure Gauge

The Digihelic® allows the selection of pressure, velocity or volumetric flow operation in several commonly used engineering units. 2 SPDT control relays with adjustable dead bands are provided along with a scalable 4-20 mA process output.

The Digihelic® allows you to require a security code prior to any changes to the user-set programming. An easy to use, menu driven keypad also lets you set all of the following: pressure, velocity or flow operation; K-factor for use with flow sensors; rectangular or circular duct for inputting area in flow applications; set point control or set point and alarm operation; high/low alarm; automatic or manual alarm reset; alarm delay; view peak and valley process readings; digital dampening for smoothing erratic process applications; Modbus® communications; and field calibration.