21000-28-05-20-018-03-02 | Bently Nevada 8 mm Proximity Probe Housing Assembly

Introduction to the 21000-28-05-20-018-03-02

When reliable vibration monitoring is critical for rotating machinery, the 21000-28-05-20-018-03-02 from Bently Nevada delivers precise proximity measurement. This housing assembly integrates a 3300 XL 8 mm probe with a 0.5 m cable, a 2 in standoff adapter, and a 1.8 in probe penetration. It is designed for hazardous area applications and meets CSA Type 4 enclosure standards. By using this assembly, engineers reduce installation costs and avoid unplanned downtime.

Key Features and Technical Specs

• Probe type: 3300 XL 8 mm with selectable hazardous area approvals.
• Cable length: 0.5 m (20 in) for flexible routing.
• Standoff adapter length: 2 in (option C dimension).
• Probe penetration: 1.8 in (option D dimension).
• Fittings: One 3/4-14 NPT plug, one reducer, and cable seal grip with grommets for 1/8–3/8 in cables.
• Mounting thread: 3/4-14 NPT.
• Material: Aluminum body with 304 stainless steel sleeve.
• Weight: 1.1 kg (2.4 lb) typical, without fittings.

A distinctive spec is the 0.5 m cable length, which reduces material waste and installation time in tight spaces. This directly lowers project costs.

Cost-Benefit Analysis

Using the 21000-28-05-20-018-03-02 minimizes total ownership cost. The aluminum body resists corrosion, extending service life and reducing replacement frequency. The 0.5 m cable eliminates excess cabling expense. Moreover, the CSA Type 4 explosion-proof rating avoids costly retrofits in hazardous areas. Over a five-year period, these factors can reduce maintenance spending by up to 20% compared to non-certified housings.

Applications and Use Cases

This housing assembly is ideal for externally mounted proximity probes on pumps, compressors, and turbines. For example, in a refinery, the 21000-28-05-20-018-03-02 monitors shaft vibration in a hydrogen compressor. The 1.8 in probe penetration allows precise gap setting, while the 3/4-14 NPT thread ensures a secure seal. Consequently, operators achieve reliable data without frequent recalibration.

Installation and Setup

Mount the assembly using the 3/4-14 NPT thread into a pre-drilled hole. For probe penetration lengths between 1.0 and 2.0 inches, counter boring the machine case may be necessary to reduce side view effects. If the total C plus D dimension exceeds 300 mm (12 in), add sleeve support near the probe to prevent resonance. The adjustment range of option D is 13 mm (±0.5 in).

Maintenance and Reliability

Inspect the O-rings and thread seal annually for wear. The 304 stainless steel sleeve resists corrosion, so typical service intervals extend to three years. Regular inspection per the manufacturer’s manual ensures consistent performance. This proactive approach avoids costly emergency repairs.

FAQ about 21000-28-05-20-018-03-02

Q: What is the probe cable length for this model?

A: The cable length is 0.5 m (20 in).

Q: What mounting thread does the 21000-28-05-20-018-03-02 use?

A: It uses a 3/4-14 NPT thread.

Q: What materials are used in the housing?

A: The body is aluminum with a 304 stainless steel sleeve.

Q: Is this assembly rated for hazardous areas?

A: Yes, it is available with CSA approvals and is rated explosion proof for hazardous areas.

Q: What is the typical weight of the assembly?

A: It weighs 1.1 kg (2.4 lb) typical, without fittings.

Product Support and Availability

The 21000-28-05-20-018-03-02 is in stock and ready to ship from Petro Auto Tech. Contact our team for ordering assistance or technical support.