The Bently Nevada 21000-28-05-00-057-04-02, also cataloged as the 21000 Proximity Probe Housing, operates as a dedicated hardware component for the stable mechanical positioning and environmental containment of eddy-current transducers within machine casing interfaces.

Configuration Breakdown

The 21000-28-05-00-057-04-02 configuration specifies a 1/2-20 UNF threaded housing assembly, incorporating a 0.5-inch NPT mounting adapter and a 57 mm (2.25 inch) length. This housing assembly is engineered to facilitate axial adjustment of the transducer tip relative to the target, ensuring the required gap for linear operation in vibration and position monitoring applications.

Hardware Specifications

Mechanical Positioning & Transducer Scaling

The 21000 series housing maintains consistent rotor dynamics observation by providing a rigid reference point. Because accurate eddy-current probe scaling requires the probe tip to remain at a fixed distance from the target, this housing features a locking nut mechanism that prevents drift once the nominal -10 VDC gap voltage is set. Proper installation involves aligning the housing so that the probe trajectory is perfectly perpendicular to the target surface, effectively mitigating potential non-linearities and signal distortions during shaft rotation.

Shipment Contents

• 1x 21000-28-05-00-057-04-02 Housing Assembly

• 1x Jam nut

• 1x O-ring seal

• 1x Installation instruction manual

Field Installation Guidelines

• Machining Requirements: The mounting boss must be machined flat and tapped to ensure the housing stands square to the shaft to prevent angular alignment errors.

• Thread Engagement: Utilize appropriate thread sealant on the NPT end if the application involves pressurized casing environments.

• Locking Protocol: Once the target gap is established, tighten the jam nut to 5.1 N-m (45 in-lb) to secure the assembly against vibration.

• Environmental Protection: Ensure the O-ring is seated correctly within the groove to maintain a hermetic seal against oil or gas ingress.

Frequently Asked Questions

• Does this housing include the probe? No, the 21000 series is a mechanical housing assembly; the proximity probe and extension cable must be sourced separately.

• What is the purpose of the 57 mm length? This specific length is intended for applications where the machine wall thickness requires a longer reach to position the probe tip correctly over the shaft.

• Can this be used for 3300 XL probes? Yes, the housing is dimensionally compatible with standard 8 mm and 5 mm 3300 XL series probes.

• Is the stainless steel material compatible with all lubricants? Stainless steel offers high resistance to standard industrial lubricants; however, check for chemical compatibility if process fluids are highly acidic.

• Why is the jam nut critical? The jam nut prevents the housing from backing out due to machine-induced vibration, which would result in a loss of gap calibration.

• Can I replace the O-ring in the field? Yes, O-rings are standard consumable items and should be inspected for degradation during routine maintenance cycles.

• Is this housing suitable for hazardous areas? The mechanical housing is passive; when paired with an approved probe and barrier, it is compatible with Ex i installations.

• What happens if the thread is cross-threaded? Cross-threading damages the machine boss; always thread by hand initially to ensure proper seating before using tools.