1. Description:

The BENTLY NEVADA 21000-34-10-00-085-04-02 is a highly specialized configuration of a Proximity Probe Housing Assembly, manufactured by Bently Nevada (now part of Baker Hughes). These assemblies are essential components in machinery protection and condition monitoring systems. They provide a robust, externally mounted enclosure for Bently Nevada proximity probes and their extension cables, enabling non-contact measurement of shaft vibration, axial position, and speed in critical rotating machinery while offering convenient external access for maintenance.

Breaking down the specific part number:

• 21000: Indicates the Proximity Probe Housing Assembly model.
• -34: Specifies the probe option: a 3300 XL 5 mm probe with a connector. This is a smaller probe diameter, suitable for limited-space applications.
• -10: Denotes a probe cable length of 1.0 meter (40 inches). This is the length of the integral cable attached to the probe inside the housing.
• -00: Refers to a Standoff Adapter (Option C Dimension) of 0 inches (0 mm). This means there is no standoff adapter included, implying the probe starts its penetration directly from the mounting surface.
• -085: Indicates a Probe Penetration (Option D Dimension) of 8.5 inches (215.9 mm). This specifies an exceptionally deep reach for the probe into the machine through the housing.
• -04: Specifies the fittings option: one 3/4-14 NPT plug only.
• -02: Indicates the Mounting Thread option: 3/4-14 NPT.

2. Application Scenarios:

Consider a large, modern steam turbine in a combined-cycle power plant. These turbines are designed with very long shafts, and critical internal components like intermediate stage bearings or shaft seals are often located extremely deep within the casing, making them nearly impossible to monitor with standard instrumentation. Any undetected abnormal shaft movement or vibration in these areas could lead to catastrophic failure, resulting in massive repair costs and prolonged power outages. In this highly demanding scenario, BENTLY NEVADA 21000-34-10-00-085-04-02 Proximity Probe Housing Assemblies would be indispensable. The unique combination of the -34 (5 mm probe) for navigating tight internal clearances and the -085 (8.5-inch probe penetration) enables the probes to reach and accurately monitor these previously inaccessible, deeply recessed shaft sections or bearings. This provides continuous, non-contact data on the turbine’s shaft vibration and axial position, feeding crucial information to the plant’s machinery protection system. The housing’s design, which allows external adjustment of the probe gap or replacement, directly addresses the severe pain points of inaccessible instrumentation and the immense costs of machine downtime for fault diagnosis.

3. Parameter:

Main Parameters Value/Description Product Model: BENTLY NEVADA 21000-34-10-00-085-04-02 Manufacturer: Bently Nevada (Baker Hughes) Product Category: Proximity Probe Housing Assembly Housing Material: Aluminum body (for 21000 series) with 304 stainless steel sleeve Compatible Probe: 3300 XL 5 mm proximity probe Probe Cable Length (internal to housing): 1.0 meter (40 inches) Standoff Adapter Length: 0 inches (0 mm) Probe Penetration (Option D Dimension): 8.5 inches (215.9 mm) Fittings: One 3/4-14 NPT plug only Mounting Thread: 3/4-14 NPT Operating Temperature Range (for associated probe): -51°C to +177°C (-60°F to +351°F) Electrical Classification: Complies with CE mark for Europe; specific certifications (e.g., CSA, BASEEFA) for hazardous areas when used with approved components. Compliance: Fully compliant with API 670 Standard for externally mounted proximity probe housings (with appropriate probe/system). Weight: Approximately 1.8 kg (4.0 lb) typical, without additional fittings.

4. Technical Principles and Innovative Values:

The BENTLY NEVADA 21000 Proximity Probe Housing Assembly incorporates core technical principles and offers innovative value, with this specific variant pushing the boundaries of probe reach:

• Innovation Point 1: Ultra-Deep Probe Penetration for Extreme Reach: The most significant innovation of the -085 option is its exceptionally long probe penetration of 8.5 inches (215.9 mm). This capability is critical for monitoring large, complex machinery where essential components are buried deep within the casing and would otherwise be unmonitorable without extensive and costly machine disassembly. This extended reach allows for comprehensive insight into critical internal machinery health.
• Innovation Point 2: Optimized Design for Confined and Deep Applications: The combination of the -34 (5 mm probe) for navigating tight internal clearances and the -10 (1.0-meter integral cable length) provides an optimized solution for extremely confined spaces at great depths. This allows for precise non-contact measurement in locations previously considered inaccessible, maximizing the effectiveness of the monitoring system.
• Innovation Point 3: External Accessibility for Simplified Maintenance & API 670 Compliance: Despite the extreme penetration, the housing assembly is engineered for external adjustment of the probe gap or replacement of the entire probe and its integral cable. This significantly reduces maintenance time and costs by eliminating the need for major machine disassembly. This, coupled with its robust construction and full compliance with API 670, ensures high reliability and streamlined maintenance in the most critical industrial applications.

5. Application Cases and Industry Value:

In an offshore oil and gas production facility, the main gas compression trains utilize large turbomachinery with deeply recessed bearings that are difficult to access for monitoring. Ensuring the continuous operation of these compressors is paramount for production, and any unscheduled downtime is astronomically expensive. By installing BENTLY NEVADA 21000-34-10-00-085-04-02 Proximity Probe Housing Assemblies at strategic, deep-seated locations, the facility gained unprecedented visibility into the health of these critical components. The 5 mm probes, with their 8.5-inch penetration, could precisely monitor the vibration and axial position of these previously inaccessible bearings. This continuous, high-precision data allowed the operators to track bearing degradation and shaft dynamics in real-time, enabling proactive scheduling of maintenance during planned shutdowns rather than reacting to sudden, catastrophic failures at sea. This direct insight into critical internal components, facilitated by the specialized Bently Nevada housing, led to a significant reduction in unscheduled compressor downtime, improved overall operational safety in a hazardous environment, and massive cost savings in maintenance and lost production.

6. Related Product Combination Solutions:

The BENTLY NEVADA 21000-34-10-00-085-04-02 is an integral part of a complete Bently Nevada proximity measurement system:

• Bently Nevada 3300 XL 5 mm Proximity Probe (included in the assembly): This specific probe is contained within the housing and performs the actual non-contact measurement.
• Bently Nevada 3300 XL 5 mm Proximitor® Sensor (e.g., 3300 XL 5mm Proximitor® Sensor): This external module receives the raw signal from the probe (via its extension cable) and converts it into a conditioned voltage output proportional to the gap.
• Bently Nevada 3300 XL Extension Cables: These cables connect the probe within the housing to the external Proximitor® Sensor, bridging the (often very significant) distance between the machinery and the monitoring cabinet.
• Bently Nevada Machinery Protection and Condition Monitoring Systems (e.g., 3500 Series, System 1): These rack-based or software-based systems receive the conditioned signals from the Proximitor® Sensors. They process the data, perform real-time vibration analysis, trigger alarms, and initiate machinery shutdowns if critical limits are exceeded.
• Conduit and Fittings: Used to protect the wiring from the housing assembly to the monitoring system, especially important in hazardous or harsh environments.

7. Installation, Maintenance, and Full-Cycle Support:

Installation of the BENTLY NEVADA 21000-34-10-00-085-04-02 requires meticulous planning and execution due to its extreme penetration. The aluminum housing assembly is securely mounted to the machine casing. Precise drilling and tapping of the mounting hole are absolutely essential to ensure the probe aligns correctly with the target shaft and reaches the desired measurement point without interference. Electrical connection involves routing the probe’s integral 1.0-meter cable within the housing to an extension cable and then to an external Proximitor® Sensor. Proper grounding and sealing of conduit connections are critical for environmental protection and signal integrity, particularly given the often challenging and hazardous environments where such deep-penetration probes are used. Commissioning involves carefully gapping the probe (adjusting its distance to the shaft) to ensure it operates within its linear range; this can be performed externally through the housing, leveraging its design for maintainability despite the extreme reach.

Routine maintenance focuses on periodic visual inspections of the housing and probe tip for cleanliness, damage, or wear, and verifying the probe gap. The external accessibility of the probe via the housing significantly simplifies these tasks, even for extremely deeply recessed probes. Troubleshooting involves checking the probe’s gap voltage, verifying cable continuity, and inspecting the Proximitor® Sensor output. As Bently Nevada is a major OEM, comprehensive full-cycle support is readily available. This includes detailed installation and maintenance manuals, technical support from factory-trained engineers, and access to genuine spare parts and calibration services globally. This robust support infrastructure ensures the long-term reliability and accuracy of machinery protection systems utilizing these critical components, even in the most demanding applications.

Contact us for tailored support and solutions for your Bently Nevada machinery monitoring systems, including assistance with installation, maintenance, troubleshooting, and sourcing genuine replacement parts for the 21000 series probe housing assemblies, particularly those with small probes and very deep penetration.