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Dwyer Series 250/451 Inclined Manometer Air Filter Gages

Precision Machined, Solid Acrylic Plastic Gages, Accurate to ±1% of Full Scale

Dwyer Durablock® Series 250-AF Gages are precision machined 1" thick solid acrylic plastic, virtually unbreakable and free of distortion. The fluid bore is precision drilled to ±.0002" to assure life long accuracy. A glass spirit level is built into the body and encapsulated to prevent damage or tampering. The scale is mirror polished chrome plated brass to assure parallax free reading by alignment of the miniscus with its reflection. Safety traps are incorporated in the body to prevent loss of fluid due to pressure surges. Red and green signal flags indicate clearly when a filter change is necessary. Gages are suitable for use in ambient temperatures of -20 to 150°F. Connection fittings are positively sealed by "O" rings but easily removed for zeroing or addition of fluid. Furnished complete with instructions.

Economy Models 451-AF and 452-AF are similar to 250 Series except they are not equipped with over pressure traps. Two A-324 1/4" compression fittings are included with each Gage but not shown. Bodies are of 5/8" thick acrylic and scales are mirror polished, epoxy coated aluminum.

Model No. 250.5-AF Economy Model No. 451-AF
for Architects and Engineers
An air filter gage for measuring the resistance to air flow through the filters shall be installed, one for each bank of filters. The gage shall be of inclined tube differential type (equipped with vent valves for zeroing) shall be of solid acrylic plastic construction with built-in level vial (and over pressure safety traps 250 Series only), shall have an adjustable mirror-polished scale, shall be furnished complete with two 5-foot lengths 1/4" tubing, two static pressure tips, mounting hardware, additional bottle of red gage oil and instructions. Gage shall be Dwyer Instruments, Inc. Catalog No. ____, reading to __in. divisions.
Standard accessories furnished are two static pressure tips with integral compression fittings and two five foot lengths of 1/4" aluminum tubing plus two compression fittings, mounting hardware and extra bottle of gage oil. A-310B 3 way vent valve
A-317 Plastic Gage plug
Optional vent valves for easy zeroing of gage are available at extra cost. Two are required per gage.

Highly accurate and easy to use yet almost indestructible, Dwyer Series 250-AF Inclined Air Filter Gages are foolproof and dependable. There are no moving parts - no mechanical linkages - nothing to wear out, jam or deteriorate from vibration. They never need calibration. The mirror polished inclined scale allows the operator to easily read minute differences in differential pressure across the filter accurately without parallax error.

The only servicing required is occasional zeroing. If cleaning is necessary, it is easily done with soap and water.

Popular Series 250 Models:
Model Number Range - Water Column Minor Divisions Inclined Scale Length - Inches Overall Size - Inches
 250-AF .10-0-1.0" .02" 5-1/2 8-1/2 x 4-1/8 x 1
 250.5-AF .10-0-1.0" .01" 8 11-3/8 x 4 x 1
 251-AF .05-0-.50" .01" 5-1/2 8-1/4 x 3-3/8 x 1
 252-AF .20-0-2.0" .02" 8 11-1/8 x 6-1/2 x 1
 209-AF .20-0-3.0" .02" 8 11-1/4 x 6-7/8 x 1
 260-AF 0-1.5" .02" 5-1/2 8-3/8 x 5-7/8 x 1
 350-AF² 0-4" .10" 4-1/2 3 x 8-1/4 x 1
Popular Series 450 Models:
Model Number Range - Water Column Minor Divisions Inclined Scale Length - Inches Overall Size - Inches
 451-AF¹ 0-1" .01" 8 11 x 2-1/2 x 5/8
 452-AF¹ 0-2" .02" 8 11 x 4 x 5/8
¹2 psi maximum working pressure
² Vertical scale
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