Overview

The heavy-duty 21000-28-05-00-040-03-02 + 330105-02-12-15-12-CN integration combines an explosion-proof proximity probe housing assembly with a 3300 XL 8 mm reverse mount probe. Engineered for critical machinery protection systems (TSI), this combined assembly excels in highly volatile, high-pressure environments like steam turbine generators, oil refining compressors, and chemical processing pumps. By protecting internal sensor elements from harsh process fluids, extreme mechanical vibration, and corrosive atmospheres, this robust assembly ensures continuous shaft vibration and axial position measurements. The integrated design directly prevents catastrophic machinery breakdowns, significantly lowers unplanned maintenance intervals, and provides real-time predictive diagnostics for high-speed rotating assets.

Hardware Codification & Suffix Analysis

The combination part number structure is broken down into precise engineering selections to simplify field identification and ordering:

21000-28-05-00-040-03-02 Proximity Probe Housing

• 21000: Base model designation for Bently Nevada Proximity Probe Housing Assemblies.

• 28: Integrates a 3300 XL 8 mm probe with multiple hazardous area approvals.

• 05: Equips a 0.5 metre (20 inches) probe cable length option.

• 00: Specifies no standoff adapter in the housing assembly.

• 040: Sets the probe penetration depth to exactly 4.0 inches.

• 03: Outfits the enclosure with one 3/4-14 NPT plug, one 3/4 to 1/2 NPT reducer, and a variable cable seal grip containing three grommet sizes (1/8 to 3/16, 1/4 to 5/16, and 5/16 to 3/8 inches).

• 02: Features a 3/4-14 NPT mounting thread option for direct vessel connection.

330105-02-12-15-12-CN 3300 XL 8 mm Reverse Mount Probe

• 330105: Base model designation for 3300 XL 8 mm Reverse Mount Probes.

• 02: Specifies a total electrical cable length of 0.2 metre (0.66 feet).

• 12: Equips a Miniature ClickLoc coaxial connector combined with a fluid-resistant FluidLoc cable.

• 15-12: Denotes specific internal mechanical configuration and mounting case lengths.

• CN: Restricts hazardous area certifications to country-specific national approvals (such as NEPSI for China markets).

Vital Technical Parameters

Troubleshooting & Compatibility FAQ

• Q: Why does this assembly utilize a reverse mount probe configuration instead of a standard threaded probe?

  A: Reverse mount probes are designed specifically to install from the rear of the housing assembly, rather than from outside the machine casing. This enables you to replace or adjust the probe without having to disassemble the machine casing or shut down critical processes.

• Q: What is the purpose of the FluidLoc cable option on the 330105 probe?

  A: FluidLoc cables contain an internal block that prevents oil, process steam, or other gases from leaking through the inner core of the coaxial cable to the external environment, preserving the explosion-proof integrity of the housing enclosure.

• Q: Can this 0.2 metre probe be connected directly to a standard Proximitor sensor?

  A: No, proximity systems are calibrated for specific electrical lengths (typically 5.0 metres or 9.0 metres). The 0.2 metre probe cable must be paired with a matching extension cable and a corresponding Proximitor to ensure accurate, calibrated displacement measurements.

Field Engineering & Installation Manual

• Proper Gap Voltage Configuration: When deploying the probe inside the housing, connect the system to a dynamic calibrator or use a digital multimeter to measure the DC bias voltage output. Slowly rotate the threaded probe into the housing sleeve until the gap voltage reaches approximately -10.0 VDC (the center point of the 3300 XL linear range). Lock the outer housing set screws securely to prevent mechanical drift under operational vibration.

• Housing Environmental Sealing: Apply high-quality PTFE thread sealant tape or compatible industrial liquid sealant to the NPT threads of the aluminum housing before mounting. Ensure the cable seal grip is tightened around the probe cable using the correct size grommet from the "03" option kit to prevent ingress of steam, oil, or particulate contaminants.

• Connector Care and Isolation: Always use the ClickLoc connector tool during mating or demating. Avoid twisting the coaxial cable, as inner core damage can alter electrical resistance and ruin system calibration. Ensure that the internal coaxial junction is kept completely clean, dry, and free of conductive oil residues.