Bently Nevada 31000-28-10-00-087-03-02 Proximity Probe Housing Assembly – 3300 XL Series

Bently Nevada 31000-28-10-00-087-03-02 — Precision Eddy-Current Probe Housing for Continuous Shaft Displacement Measurement

The Bently Nevada 31000-28-10-00-087-03-02 is a factory-assembled proximity probe housing unit designed for non-contact, continuous measurement of radial shaft vibration and axial position in high-speed rotating machinery. Operating on the eddy-current principle, the assembly converts mechanical displacement into a proportional DC voltage signal — 7.87 V/mm (200 mV/mil) nominal sensitivity — that feeds directly into Bently Nevada 3300 and 3500 Series monitor racks without signal conditioning intermediaries.

The part number suffix structure encodes the full mechanical and electrical configuration: thread size (M10×1), housing material grade (316 stainless steel), cable length (3 m extension, suffix -03), and connector termination (-02 integral coaxial). This deterministic naming convention eliminates ambiguity during spare-parts procurement and ensures exact form-factor replacement in existing installations without dimensional re-verification.

Deployment environments include steam and gas turbines at bearing journal positions, centrifugal compressors in petrochemical and LNG service, large-frame induction motors requiring air-gap monitoring, and marine propulsion shafting subject to alignment drift. The housing positions the probe tip at a controlled radial standoff from the target shaft surface, maintaining the calibrated linear measurement range of 0.25 mm to 2.26 mm (10–89 mil) across the full thermal excursion of the machine from cold-start to rated operating temperature.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

The eddy-current measurement chain in the 31000-28-10-00-087-03-02 begins at the probe coil, a precision-wound inductive element encapsulated in a thermally stable ceramic-filled polymer tip. The coil is driven by a high-frequency oscillator (typically 1.0 MHz carrier) housed in the paired Proximitor driver. When the conductive shaft surface enters the probe’s electromagnetic field, eddy currents are induced in the target, loading the oscillator circuit and producing a proportional reduction in oscillation amplitude. The Proximitor demodulates this amplitude-modulated signal and outputs a DC voltage linearly proportional to the gap distance.

The 316L stainless steel housing serves a dual function: mechanical positioning and electromagnetic shielding. The housing wall thickness is calculated to attenuate external RF interference without introducing ferromagnetic permeability that would distort the probe’s near-field geometry. The armored coaxial cable — stainless steel braid over a low-loss dielectric — maintains a controlled characteristic impedance (typically 50 Ω) from probe tip to Proximitor input, preventing standing-wave reflections that would introduce gain non-linearity at the measurement frequencies involved.

Thermal compensation is addressed through the matched coefficient of thermal expansion (CTE) between the probe tip encapsulant and the housing body. Over the −40 °C to +177 °C operating range, the probe tip-to-housing dimensional relationship remains within ±0.01 mm, preserving the factory-set gap calibration without field re-zeroing. This is particularly significant in hot-section gas turbine applications where bearing housing temperatures can cycle 120 °C between cold-start and full-load conditions within a single operating shift.

The IP67 sealing is achieved through a dual O-ring arrangement at the cable entry gland, with a secondary epoxy potting layer over the coil termination. This construction prevents moisture ingress in wash-down environments and condensation-prone bearing housings, eliminating the insulation resistance degradation that is the primary failure mode of non-sealed proximity probe assemblies in humid climates.

System Integration Benefits

• Zero-wear measurement loop: Non-contact eddy-current technology eliminates mechanical contact between sensor and rotating shaft. MTBF exceeds 100,000 hours in continuous turbomachinery service, reducing planned maintenance intervals for the measurement system itself.
• Direct rack compatibility: The 31000-28-10-00-087-03-02 interfaces natively with Bently Nevada 3300 and 3500 Series monitor racks via the 330180 Proximitor driver. No signal conditioning, impedance matching, or intermediate transmitter is required, preserving the full 7.87 V/mm sensitivity chain to the monitor input card.
• Deterministic real-time response: The eddy-current signal path has a flat frequency response from DC to beyond 10 kHz, enabling the monitor rack to capture shaft vibration components from 1× running speed through high-order harmonics and sub-synchronous instability frequencies without bandwidth-induced phase lag.
• API 670 compliance out of the box: The assembly meets API 670 5th Edition requirements for proximity probe systems used in turbomachinery protection. This eliminates the engineering review burden during SIL assessment for safety-instrumented shutdown loops.
• ATEX/IECEx Zone 1 certification: The housing assembly carries ATEX and IECEx approval for use in Zone 1 and Zone 2 hazardous areas, enabling deployment in compressor trains handling flammable hydrocarbons without additional barrier hardware at the probe location.
• Calibration traceability: Each unit ships with factory calibration data traceable to NIST reference standards. The calibration certificate documents the actual sensitivity curve across the full linear range, providing the baseline for ISO 17359 condition monitoring program documentation.
• Corrosion-resistant construction for aggressive environments: 316L SS housing and armored cable withstand H₂S concentrations, chloride-laden marine atmospheres, and alkaline wash-down chemicals. This extends service life in offshore platforms and coastal petrochemical facilities where carbon steel probe housings require annual replacement.
• Diagnostic transparency via orbit plot capability: When installed in orthogonal XY pairs at each bearing journal, the 31000-28-10-00-087-03-02 provides the raw displacement signals required for shaft orbit plot generation in the 3500 Series monitor. Orbit plots expose rotor dynamic anomalies — oil whirl, misalignment, rub — that scalar vibration amplitude trending cannot distinguish, enabling root-cause diagnosis without machine disassembly.

Quality Assurance & Global Logistics

Every 31000-28-10-00-087-03-02 unit stocked at siemensplc.com is sourced through verified industrial distribution channels with full traceability to Bently Nevada / Baker Hughes manufacturing records. Pre-shipment inspection protocol includes: visual and dimensional verification against OEM engineering drawings; coaxial cable continuity and insulation resistance test (minimum 100 MΩ at 500 VDC); part number label cross-check against physical configuration; and anti-static, desiccant-packed export carton preparation compliant with ISTA 2A transit testing standards.

Shipments originate from Xiamen, China — a major international logistics hub with direct air freight connections to Singapore, Dubai, Frankfurt, Los Angeles, and Houston. Standard export documentation includes commercial invoice, packing list, and certificate of origin. For projects requiring ATA Carnet, CITES exemption letters, or end-user certificates, our export compliance team prepares documentation within 24 hours of order confirmation. Typical transit times: Southeast Asia 2–4 days, Middle East 3–5 days, Europe 5–7 days, North America 5–8 days via express air freight.

All units are covered by a 12-month warranty from the date of shipment against manufacturing defects. Warranty claims are processed with a target 5-business-day resolution, including advance replacement shipment for critical plant applications where downtime cost justifies expedited handling.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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