Fittings-Filters-Mufflers

Supported Applications

The Dwyer Fittings & Filters series provides accessories for Dwyer instrumentation products, specifically designed to interface with Magnehelic® and Capsuhelic® gauges. The product line includes fittings, adapters, unions, plugs, and filters intended for various tubing and pipe connections in pressure measurement systems.

Documented applications include:

• Magnehelic® Gauges: Line filter A-392 (1/8" female NPT x 1/8" male NPT) is specified for Magnehelic® gages.
• Capsuhelic® Gauges: Line filter A-391 (1/4" female NPT X 1/4" male NPT) is specified for Capsuhelic® gages.
• Air Velocity Transmitters: Probe extension adaptor A-398 supports the series 640 air velocity transmitter, featuring a brass body with 1/2" female NPT x 5/16" compression connections.

Operating Conditions & Performance

The source documentation does not provide specific technical performance specifications such as pressure ratings, temperature limits, accuracy classes, or response times for this series. The product descriptions focus on physical configuration and material composition rather than operational envelopes.

Safety Notice: Products in this series are subject to California Proposition 65 warnings regarding exposure to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, refer to www.P65Warnings.ca.gov.

Configuration Options

The series offers a broad range of connection types and materials to accommodate different tubing sizes and installation requirements. Wetted materials across the line include brass, nylon, plated steel, sintered metal, stainless steel (316 SS), aluminum, rubber, and plastic.

Connection Types

The available fittings support various thread standards and tube interfaces:

• NPT Threads: Models include 1/8" NPT close coupled street ell (A-329), pipe plugs (A-330), bushings (A-332, A-333), nipples (A-334), couplings (A-337), and reducers (A-349).
• Compression Fittings: Options include elbow compression fittings (A-323) for 1/8" NPT to 1/4" metal tubing, straight compression fittings (A-324, A-326), and "T" compression fittings (A-346).
• Tube Unions: Nylon tube unions are available in 5/16" (A-327) and 1/4" (A-328) sizes.
• Hose Barbs & Adaptors: The series includes brass adaptors for rubber or plastic tubing (A-339, A-340), Serval adaptors for gas appliances with N.F. threads (A-338), and 316 SS hose barb to BSPT fittings (A-339-SS).

Filters & Plugs

• Filter Vent Plugs: Model A-331 is a 1/8" NPT filter vent plug constructed of nylon and sintered metal. The stainless steel variant, A-331-SS (1/8" BSPT), serves as a replacement filter for the A-464-SS.
• Hole Plugs: Plastic hole plugs are available in 1/2" size, packaged at 20 per bag (A-385).

Key Product Differences

Variants within the series differ primarily by connection geometry, thread standard, and material composition. Key distinctions include:

• Material Composition: Fittings are offered in brass (e.g., A-329, A-334), nylon/plastic (e.g., A-327, A-340), plated steel (A-330), aluminum with gasket and sheet metal screws for flanges (A-345), and 316 SS stainless steel (A-339-SS).
• Thread Standards: The series supports both NPT threads (e.g., A-323, A-330) and BSPT threads (specifically the A-331-SS filter vent plug).
• Tubing Compatibility: Adaptors are configured for specific inner diameters of rubber or plastic tubing, including 1/8" ID, 3/16" ID, and 1/4" ID options (e.g., A-339, A-340, A-342).
• Specialized Components: The series includes a terminal tube made of brass with a 1/4" diameter and 8" length (A-344), noted as not shown in the source image but described in the model chart.