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. 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. 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. OVERPRESSURE PROTECTION Blowout plug is comprised
of a rubber plug on the rear which functions as a relief valve by
unseating and venting the gage interior when over pressure reaches
approximately 25 psig (1.7 bar). To provide a free path for
pressure relief, there are four spacer pads which maintain 0.023"
clearance when gage is surface mounted. Do not obstruct the gap
created by these pads. The blowout plug is not used on models above
180" of water pressure, medium or high pressure models, or on gages
which require an elastomer other than silicone for the diaphragm.
The blowout plug should not be used as a system overpressure
control. High supply pressures may still cause the gage to fail due
to over pressurization, resulting in property damage or serious
injury. Good engineering practices should be utilized to prevent
your system from exceeding the ratings or any component. O-ring
seal for cover assures pressure integrity of case. Samarium Cobalt
magnet mounted at one end of range spring rotates helix without
mechanical linkages.
