1-445L 0.445" Bore Dia Threaded Step Down Thermowells

Supported Applications

The Omega Series 445L is a standard threaded thermowell designed for industrial glass thermometer insertion. It accommodates liquid-in-glass thermometers manufactured to S.A.M.A. standards, featuring a tapered bore with a 0.008" oversize dimension intended to prevent the thermometer bulb from expanding into the well and becoming stuck during removal.

Documented media compatibility includes water, steam, air, gas, and similar density fluids. The series is compatible with OMEGA® NB1, NB2; PR-12, PR-14, and NPT-style probes, as well as DialTemp™ Thermometers.

Operating Conditions & Performance

The Series 445L utilizes a lagging extension design with an internal diameter of 0.445" for glass thermometer insertion. The theoretical end of the taper has a diameter of 11/16 DIA.

Maximum fluid velocity limits are defined by material and insertion length in feet per second (fps). For shorter insertion lengths, specific values account for water flow at higher velocities; these safe values for water appear in parentheses within specification tables. Unbracketed values apply to steam, air, gas, and similar density fluids.

Pressure-temperature ratings are available via the manufacturer's website reference (omega.com). The series supports insertion lengths ranging from 2⅝ inches up to 20⅛ inches depending on the model configuration.

Maximum Fluid Velocity by Material

• A.I.S.I. 304 & 316 (¾"-445L): Values range from 9.9 fps to 382 (131) fps depending on insertion length.
• Monel® (¾"-445L): Values range from 8.5 fps to 277 (105) fps depending on insertion length.
• A.I.S.I. 304 & 316 (1"-445L): Values range from 10.8 fps to 382 (190) fps depending on insertion length.
• Monel® (1"-445L): Values range from 9.4 fps to 277 (152) fps depending on insertion length.

Configuration Options

The Series 445L is offered with standard process connections of ¾" NPT and 1" NPT, with other thread sizes available upon request. Wetted materials include Carbon Steel (C-1018), Brass (ASTM B-16), A.I.S.I. 304, A.I.S.I. 316, and Monel®.

Additional design configurations such as socket weld, heavy duty, and flanged types are available outside the standard threaded series. Metric models are also offered via omega.com. PFA coating is an available option for specific applications.

Dimensional Configurations

• Nominal Bulb Lengths: 6", 9", 12", 18", and 24" options are documented in the model number guide.
• Lagging Extension (T): Standard lengths include 2½" for shorter models and 3" for longer insertion depths.
• Bulb Length A: Varies by nominal bulb length, typically adding ⅛ inch to the nominal value (e.g., 6⅛", 9⅛").
• Insertion Length U: Ranges from 2⅝" for the shortest models up to 20⅛".
• Shank Diameter Q: Specified as "—" (not applicable) for shorter insertion lengths and 7/8" or 1" depending on thread size for longer models.

Ordering Specifications

The model number structure follows the format: <Ext Thread P>-445L-<Nom Bulb Length><E>-<Material Code>. Material codes include "304SS" for 304 Stainless Steel, "316SS" for 316 Stainless Steel, "CS" for Carbon Steel, and "BRASS".

Key Product Differences

Variants within the Series 445L differ primarily by external thread size (¾ NPT vs. 1 NPT), nominal bulb length, insertion depth, and wetted material selection. The dimensional tables distinguish between "S" series models (Brass/Carbon Steel) and "L" series models (A.I.S.I. 304 & 316/Monel®).

For example, the ¾ NPT connection supports insertion lengths from 2⅝ to 20⅛ inches across various bulb configurations, while the 1 NPT connection follows a similar dimensional progression with adjusted shank diameters. Specific velocity limits vary significantly between Carbon Steel/Brass constructions and stainless steel/Monel® options at identical insertion depths.