Description
Bently Nevada 21000-16-05-15-114-03-02
Technical Specifications
- Base Model: 21000 aluminum proximity probe housing assembly
- Probe Type: 3300 XL 8 mm reverse mount proximity probe
- Probe Cable Length: 0.5 meter (20 inches)
- Standoff Adapter Length: 1.5 inches (38 mm)
- Probe Penetration Depth: 11.4 inches (290 mm)
- Fittings Configuration: One 3/4-14 NPT plug, one 3/4-14 to 1/2-14 NPT reducer, one cable seal grip with grommets
- Mounting Thread: 3/4-14 NPT
- Housing Material: Aluminum body with 304 stainless steel sleeve
- Weight: 1.1 kg (2.4 lb) typical without fittings
- Operating Temperature: -51°C to +177°C (-60°F to +351°F)
- Enclosure Rating: CSA Type 4
- Hazardous Area Approval: CSA certified explosion-proof for Class I Divisions 1 and 2 Groups C and D, Class II Divisions 1 and 2 Groups E, F, and G
Functional Features
- Extended 11.4 inch penetration for deep mounting applications
- All-metal aluminum and stainless steel construction
- Pre-installed reverse mount 3300 XL 8 mm probe
- External gap adjustment without machine disassembly
- Multi-size cable seal grip for various conduit configurations
- API 670 standard compliance for externally mounted probe housings
- Explosion-proof certification for hazardous atmospheres
Application Scenarios
- Large-frame steam turbines with thick bearing housings
- Heavy-duty centrifugal compressors in petrochemical plants
- Industrial gas turbines with extended casing walls
- Boiler feed pumps with deep stuffing box penetrations
- Large gearboxes requiring deep probe access
Performance Parameters
- Probe linear range: 2.0 mm (80 mils)
- Scale factor: 7.87 V/mm (200 mV/mil)
- Target gap voltage: -10 Vdc at center of linear range
- Maximum C plus D dimension: 13.5 inches for 0.5 meter cable with non-visible label
- Vibration frequency response: 0 to 10 kHz
Material Composition
- Housing body: Cast aluminum alloy
- Probe sleeve: AISI 304 stainless steel
- Dome cover: Aluminum with protective coating
- O-rings: Fluorocarbon elastomer
- Probe case: AISI 304 stainless steel
- Probe tip: Polyphenylene sulfide
Structural Characteristics
- Extended sleeve length of 11.4 inches requires careful handling during installation
- Standard 3/4-14 NPT mounting thread
- Integrated 1.5 inch standoff adapter
- Dome cover access for internal adjustments
- Conduit port with threaded connection
Working Principle The housing positions the reverse mount probe tip at the precise distance from the rotating shaft through the combined length of the standoff adapter and probe sleeve. The 11.4 inch penetration depth is achieved by the extended sleeve, which guides the probe from the external mounting surface through the machine casing to the measurement point. The eddy-current probe generates a high-frequency electromagnetic field at its tip, and impedance changes caused by the proximity of the conductive shaft are converted into a proportional voltage signal by the associated Proximitor sensor.
Installation Requirements
- Verify adequate internal clearance for 11.4 inch penetration before installation
- Machine mounting boss must accommodate full sleeve length
- Minimum 5 full threads of 3/4-14 NPT engagement required
- Additional sleeve support mandatory due to length exceeding 12 inches
- Apply thread sealant to prevent lubricating fluid migration
- Adjust probe gap to achieve -10 Vdc output
Usage Precautions
- Extended sleeve length requires additional support to prevent resonance
- Probe cable must be longer than sleeve to allow proper connection
- Handle with care during installation to prevent sleeve bending
- Verify dome cover O-ring seal after each opening
- Inspect sleeve for mechanical damage before installation
