Product Overview

The Bently Nevada 21022-28-05-017-03 is a dual axial probe housing assembly. This assembly consists of two proximity probes installed in an externally mounted protective enclosure. You mount this housing on the machine end nearest the thrust bearing. Both probes then observe the shaft end for axial thrust position movement. The enclosure mounts onto the machine case using four standard machine screws. Probe sleeves and adapters install directly through two 3/4-inch NPT threaded holes. The 21022-28-05-017-03 meets the American Petroleum Institute's (API) 670 Standard for axial thrust position transducer housings. External mounting allows probe adjustments without opening the machine. A removable cover provides easy access for setting the probe gaps.

Technical Specifications

General Specifications

Configuration Options

Fittings Kit Contents (Option 03)

• Two cable seal grips with grommets for 1/8-inch to 3/16-inch cables

• Two cable seal grips with grommets for 1/4-inch to 5/16-inch cables

• Two cable seal grips with grommets for 5/16-inch to 3/8-inch cables

• Two 3/4-14 to 1/2-14 NPT reducers

Note: Fittings are supplied as a kit and are not installed when the housing ships.

Design & Construction

The 21022-28-05-017-03 housing uses sand-cast aluminum alloy with 0.3% copper content maximum. This copper-free specification prevents galvanic corrosion in humid environments. Sleeves within the housing are fabricated from 304 stainless steel for durability. Two 3/4-inch NPT threaded holes accept the probe sleeve assemblies. The protective enclosure shields probes, probe leads, and extension cables from dust and splashing liquid. Consequently, environmental factors do not affect measurement reliability. The removable cover on the enclosure provides convenient access for gap setting. For axial thrust monitoring, this housing meets API 670 requirements.

API 670 Compliance

The 21022-28-05-017-03 complies with the American Petroleum Institute's Standard 670. This standard specifies requirements for vibration, axial position, and bearing temperature monitoring systems. API 670 compliance is essential for turbomachinery in refineries and petrochemical plants. The dual axial probe configuration satisfies the API requirement for redundant thrust measurement. Two independent probes observe the same shaft end position. Therefore, a single probe failure does not cause loss of protection. The Bently Nevada 21022-28-05-017-03 meets these rigorous industry standards.

Probe Compatibility

Option 28 specifies two 3300 XL 8 mm probes with multiple approvals. Each probe includes a connector for easy installation. The 0.5 metre cable length (option 05) connects each probe to its extension cable. Notably, the 3300 XL 11 mm probe is not available with the 0.5 metre cable length. For 11 mm probes, order a different cable length option instead. The 1.7 inch penetration (option 017) determines how far each probe extends toward the shaft target. This penetration depth works with most thrust collar configurations. The 21022-28-05-017-03 accepts only 8 mm probes with this specific cable length.

Installation Guidelines

Follow these steps for proper installation of the 21022-28-05-017-03.

1. Prepare two 3/4-inch NPT threaded holes on the machine case near the thrust bearing.

2. Mount the housing enclosure using four standard machine screws.

3. Insert the probe sleeve assemblies through the 3/4-inch NPT holes.

4. Thread the 3300 XL 8 mm probes into the sleeve assemblies.

5. Connect the 0.5 metre probe cables to extension cables using the connectors.

6. Install the fittings kit (option 03) for cable sealing. Select the correct grommet size for your cable.

7. Set the probe gaps through the removable cover access port.

8. Secure the cover and verify all fittings are tight.

Note: The 21022-28-05-017-03 fittings ship as a separate kit. Install these fittings during field installation. The housing itself arrives without pre-installed cable seals. For 11 mm probes, select a different cable length option.

Packaging List

• One Bently Nevada 21022-28-05-017-03 Dual Axial Probe Housing Assembly

• Two 3300 XL 8 mm proximity probes with connectors (pre-installed in sleeves)

• Two 0.5 metre probe cables (attached to probes)

• One fittings kit (option 03) with cable seal grips and NPT reducers

• One product installation manual

• One anti-static protective bag for each probe

Common FAQs

1. What is the purpose of the 21022-28-05-017-03?

This housing assembly mounts two proximity probes for axial thrust position monitoring. You install it on the machine end nearest the thrust bearing. Both probes observe the same shaft end simultaneously. For API 670 compliant systems, this dual configuration provides redundant thrust measurement. The 21022-28-05-017-03 protects probes from environmental damage as well.

2. What probes work with the 21022-28-05-017-03?

Option 28 specifies two 3300 XL 8 mm probes with multiple approvals. The 0.5 metre probe cable length (option 05) is specifically for these 8 mm probes. For 3300 XL 11 mm probes, choose a different cable length option. The 21022-28-05-017-03 with option 28 accepts only 8 mm probes.

3. Does the 21022-28-05-017-03 meet API standards?

Yes, this housing meets the American Petroleum Institute's Standard 670 for axial thrust position transducer housings. API 670 compliance is required for turbomachinery in refineries and petrochemical plants. The dual probe configuration satisfies redundancy requirements as well. Therefore, the 21022-28-05-017-03 suits critical rotating machinery applications.

4. What is the penetration depth of the probes in the 21022-28-05-017-03?

Option 017 specifies 1.7 inches of probe penetration. This distance measures how far each probe extends toward the shaft target. The 1.7 inch penetration works with most thrust collar configurations. For different penetration requirements, order a different option code. The 21022-28-05-017-03 with 017 suits standard thrust bearing installations.

5. Are the fittings pre-installed on the 21022-28-05-017-03?

No, the fittings ship as a separate kit and are not installed when the housing arrives. Option 03 includes two cable seal grips with three grommet sizes each. Two 3/4-14 to 1/2-14 NPT reducers are also included. You install these fittings during field installation. This approach prevents damage during shipping. The 21022-28-05-017-03 requires final assembly at your facility.

Why Choose This Housing Assembly?

The Bently Nevada 21022-28-05-017-03 delivers reliable axial thrust monitoring for critical turbomachinery. API 670 compliance satisfies refinery and petrochemical requirements. Two 3300 XL 8 mm probes provide redundant thrust measurement. The aluminum housing with stainless steel sleeves resists corrosion effectively. External mounting allows probe adjustments without machine disassembly. A removable cover simplifies gap setting procedures. For steam turbines, compressors, and large pumps, choose the 21022-28-05-017-03.