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Single Pressure Transmitters

Standard Magnehelic® Pressure Gage has a large, easy-to-read 4" dial.

Patent Nos. 4,030,365 5,012,378

Select the Magnehelic® gage for high accuracy--guaranteed within 2% of full scale--and for the wide choice of 81 models available to suit your needs precisely. Using Dwyer's simple, frictionless Magnehelic® gage movement, it quickly indicates low air or non-corrosive gas pressures--either positive, negative (vacuum) or differential. The design resists shock, vibration and over-pressures. No manometer fluid to evaporate, freeze or cause toxic or leveling problems. It's inexpensive, too.

The Magnehelic® gage is the industry standard to measure fan and blower pressures, filter resistance, air velocity, furnace draft, pressure drop across orifice plates, liquid levels with bubbler systems and pressures in fluid amplifier or fluidic systems. It also checks gas-air ratio controls and automatic valves, and monitors blood and respiratory pressures in medical care equipment.

SPECIFICATIONS

Service: Air and non-combustible, compatible gases. (Natural Gas option available.)
Wetted Materials: Consult factory.
Housing: Die cast aluminum case and bezel, with acrylic cover, Exterior finish is coated gray to withstand 168 hour salt spray corrosion test.
Accuracy: ±2% of full scale (±3% on -0, -100PA, -125PA, -10MM and ±4% on -00, -60PA, -6MM ranges), throughout range at 70°F (21.1°C).
Pressure Limits: -20" Hg. to 15 psig.† (-0.677 bar to 1.034 bar); MP option; 35 psig (2.41 bar), HP option; 80 psig (5.52 bar).
Overpressure: Relief plug opens at approximately 25 psig (1.72 bar), standard gages only.
Temperature Limits: 20 to 140°F.* (-6.67 to 60°C).
Size: 4" (101.6 mm) Diameter dial face.
Mounting Orientation: Diaphragm in vertical position. Consult factory for other position orientations.
Process Connections: 1/8" female NPT duplicate high and low pressure taps - one pair side and one pair back.
Weight: 1 lb 2 oz (510 g), MP & HP 2 lb 2 oz (963 g).
Standard Accessories: Two 1/8" NPT plugs for duplicate pressure taps, two 1/8" pipe thread to rubber tubing adapters and three flush mounting adapterswith screws. (Mounting and snap ring retainer substituted for 3 adapters in MP & HP gage accessories.)

*Low temperature models available as special option.
†For applications with high cycle rate within gage total pressure rating, next higher rating is recommended. See "Options/Accessories" Page.

FEATURES

Quality Design & Construction Features

Bezel provides flange for flush mounting in panel.
Clear plastic face is highly resistant to breakage. Provides undistorted viewing of pointer and scale.
Precision litho-printed scale is accurate and easy to read.
Red tipped pointer of heat treated aluminum tubing is easy to see. It is rigidly mounted on the helix shaft.
Pointer stops of molded rubber prevent pointer over-travel without damage.
"Wishbone" assembly provides mounting for helix, helix bearings and pointer shaft.
Jeweled bearings are shock-resistant mounted; provide virtually friction-free motion for helix. Motion damped with high viscosity silicone fluid.
Zero adjustment screw is conveniently located in the plastic cover, and is accessible without removing the cover. O-ring seal provides pressure tightness.
Helix is precision made from an alloy of high magnetic permeability. Mounted in jeweled bearings, it turns freely, following the magnetic field to move the pointer across the scale.
Samarium Cobalt magnet mounted at one end of range spring rotates helix without mechanical linkages.
Calibrated range spring is flat spring steel. Small amplitude of motion assures consistency and long life. It reacts to pressure on diaphragm. Live length adjustable for calibration.
Silicone rubber diaphragm with integrally molded O-ring is supported by front and rear plates. It is locked and sealed in position with a sealing plate and retaining ring. Diaphragm motion is restricted to prevent damage due to overpressures.
Die cast aluminum case is precision made and iridite-dipped to withstand 168 hour salt spray corrosion test. Exterior finished in baked dark gray hammerloid. One case size is used for all standard pressure options, and for both surface and flush mounting.
Blowout plug of silicone rubber protects against overpressure on 15 psig rated models. Opens at approximately 25 psig.
O-ring seal for cover assures pressure integrity of case.

Custom models can be provided for OEM customers. For special units with scales reading in ounces per square inch, inches of mercury, other metric units, etc., contact the factory.

Options/Accessories

Adjustable Signal Flag Integral with plastic gage cover. Available for most models except those with medium or high pressure construction. Can be ordered with gage or separate.		LED Setpoint Indicator Bright red LED on right of scale shows when setpoint is reached. Field adjustable from gage face, unit operates on 12 - 24 VDC. Requires MP or HP style cover and bezel.

A-432 Portable Units Combine carrying case with any Magnehelic® gage of standard range, except high pressure connection. Includes 9 ft. (2.7 m) of 3/16" I.D. rubber tubing, standhang bracket, and terminal tube with holder.		A-605 Air Filter Gage Accessory Package Adapts any standard Magnehelic® gage for use as an air filter gage. Includes aluminum surface mounting bracket with screws, two 5 ft. lengths of 1/4" aluminum tubing, two static pressure tips and two molded plastic vent valves, integral compression fittings on both tips and valves.

Transparent Overlays Furnished in red, green, or yellow to highlight and emphasize critical pressures.

MOUNTING. A single case size is used for most models of Magnehelic® gages. They can be flush or surface mounted with standard hardware supplied. With the optional A-610 Pipe Mounting Kit they may be conveniently installed on horizontal or vertical 1-1/4" to 2" pipe. Although calibrated for vertical position, many ranges above 1" may be used at any angle by simply re-zeroing. However, for maximum accuracy, they must be calibrated in the same position in which they are used. These characteristics make Magnehelic gages ideal for both stationary and portable applications. A 4-9/16" hole is required for flush panel mounting. Complete mounting and connection fittings plus instructions are furnished with each instrument. VENT VALVES In applications where pressure is continuous and the Magnehelic® gage is connected by metal or plastic tubing which cannot be easily removed, we suggest using Dwyer A-310A vent valves to connect gage. Pressure can then be removed to check or re-zero the gage. HIGH AND MEDIUM PRESSURE MODELS Installation is similar to standard gages except that a 4-13/16" hole is needed for flush mounting. The medium pressure construction is rated for internal pressures up to 35 psig and the high pressure up to 80 psig. Available for all models. Because of larger case size, the medium pressure and high pressure models will not fit in a portable case. Installation of the A-321 safety relief valve on standard Magnehelic® gages often provides adequate protection against infrequent overpressure. OPTIONS -- Consult Factory for Pricing -ASF Adjustable Signal Flag -HP High Pressure Option -LT Low Temperatures to -20°F -MP Med. Pressure Option -SP Setpoint Indicator Scale Overlays Red, Green, Yellow, Mirrored or Combination, Specify Locations ACCESSORIES -- See "Ordering" Page A-299 Surface Mounting Bracket A-300 Flat Flush Mounting Kit A-310 3-Way Vent Valve A-321 Safety Relief Valve A-432 Portable Kit A-605 Air Filter Kit A-610 Pipe Mount Kit