3/4-385W 0.385" Bore Diameter Socket-Weld Design Thermowells

Supported Applications

The Omega Series 385W Socket-Weld Design Thermowells are engineered for temperature measurement applications using standard length ¼" diameter elements. These thermowells protect sensing instruments in processes involving water, steam, air, gas, and similar density fluids.

Operating Conditions & Performance

The Series 385W features a socket-weld design with a ¾" or 1" nominal pipe size welding shoulder compatible with ASA welding fittings and flanges. The well diameter is specified as 49/64 DIA. (approx. 0.7656 in). Maximum fluid velocity limits vary by material, insertion length, and media type:

• Carbon Steel Wells: For a 2½" insertion length, the maximum velocity is 426 feet per second for steam, air, gas, or similar density fluids; values in parentheses (e.g., 260) are safe limits for water flow.
• A.I.S.I. 304 & 316 Wells: For a 2½" insertion length, the maximum velocity is 449 feet per second for steam, air, gas, or similar density fluids; values in parentheses (e.g., 360) are safe limits for water flow.

Velocity ratings decrease as insertion length increases. For example, at a 22½" insertion length, the maximum velocity is 7.7 feet per second for Carbon Steel and 8.0 feet per second for A.I.S.I. 304 & 316 stainless steel wells.

Configuration Options

The series offers configurable dimensions and materials to accommodate specific installation requirements:

• Pipe Size Options: Available with a ¾" Nominal (1.050" Diameter) or 1" Nominal (1.315" Diameter) welding shoulder.
• Insertion Lengths (U): Configurable in increments of 2½, 4½, 7½, 10½, 13½, 16½, and 22½ inches.
• Stem Lengths (A): Available lengths include 4, 6, 9, 12, 15, 18, and 24 inches.
• Wetted Materials: Constructed from Carbon Steel (C-1018), A.I.S.I. 304 stainless steel, or A.I.S.I. 316 stainless steel. Brass is also available for specific configurations.

Additional options include a Lagging Extension to permit the use of standard element lengths and Cap and Chain Options (Brass cap suffix 'CC-Brass' or 304SS cap suffix 'CC'). PFA coating availability should be verified via omega.com. Metric models are also available.

Key Product Differences

The Series 385W is distinguished by its socket-weld design and specific bore diameter of approximately 0.7656 in, intended for ¼" elements. Model numbers follow the format Pipe Size-385W-U<Insertion Length>/2-Material. For example, a model with a ¾" pipe size, 10½" insertion length, and 304 stainless steel construction is designated as 3/4-385W-U71/2-304SS (note: the 'U' code in the text description maps to specific lengths; verify exact model number construction against the provided table). The series supports compatibility with OMEGA® NB1, NB2; PR-12, PR-14, and NPT-style probes, as well as DialTemp™ Thermometers. Wells for larger pipe sizes are available upon request.