21128-04-01 | Bently Nevada -29°C to +121°C Velocity Transducer Housing

Introduction to the Bently Nevada 21128-04-01

When harsh environmental conditions threaten the reliability of your velocity sensors, the 21128-04-01 from Bently Nevada provides a robust solution. This housing is constructed from 303 stainless steel and designed to meet NEMA 4X and IP65 requirements when properly installed. It resists moisture and corrosion, ensuring your sensor remains operational in demanding industrial settings.

Key Features & Technical Specs

• Temperature Rating: -29°C to +121°C (-20°F to +250°F)
• Moisture Resistance: Resistant to moisture and corrosion but not submersible
• O-ring Material: Neoprene
• Mounting Thread and Cap Option: 04 = 1/2-in 14 BSP (G 1/2-in)
• Cable Exit Fitting Option: 01 = 1/2-in NPT plug
• Weight: 1.6 kg (3.55 lb) without velocity sensor or fittings
• Internal Mounting Thread: 1/2-in 20 UNF (for 21128 and CA21128)
• Outlet Port Size: 1/2-in NPT

One distinctive spec is the wide temperature range of -29°C to +121°C. This allows the housing to perform reliably in both freezing outdoor environments and high-heat industrial processes, reducing the need for multiple housing variants.

Real-World Applications

Engineers often select the 21128-04-01 for non-hazardous areas where water spray, corrosion, or physical impact is a concern. For example, in a paper mill, the housing protects velocity sensors from hose-directed water and chemical exposure. This durability minimizes sensor replacement costs and unplanned downtime.

Installation Guide

Mount the housing using the 1/2-in 14 BSP internal thread. Ensure the O-ring (neoprene) is properly seated to maintain the IP65 seal. Use the 1/2-in NPT plug for the cable exit. For Velomitor CT sensors, order the tall cap option. When using the 21128 Housing, cable part number 89477-AA is necessary to connect the Velomitor Sensor to a monitor.

Maintenance & Reliability

Periodically inspect the O-ring for wear or cracking, especially after temperature cycling. Verify that the housing remains sealed against moisture. The 303 stainless steel construction resists corrosion, but regular cleaning with a damp cloth helps maintain the NEMA 4X rating. Avoid submerging the housing, as it is not submersible.

Compatibility & Integration

The 21128-04-01 is designed for Bently Nevada velocity sensors such as the Velomitor CT, 9200, and 74712 Seismoprobe. For explosion-proof requirements, use the CA21128 version with a CSA-approved sensor. For BASEEFA installations, the BA42608 housing is required. Always verify sensor compatibility with the housing thread option.

Frequently Asked Questions

Q: What is the temperature rating of the 21128-04-01?

A: The temperature rating is -29°C to +121°C (-20°F to +250°F).

Q: Is the 21128-04-01 submersible?

A: No, it is resistant to moisture and corrosion but is not submersible.

Q: What mounting thread does the 21128-04-01 use?

A: It uses a 1/2-in 14 BSP (G 1/2-in) mounting thread and cap option.

Q: What cable is needed to connect a Velomitor sensor?

A: Cable part number 89477-AA is necessary to connect the Velomitor Sensor to a monitor.

Q: What is the weight of the housing without a sensor?

A: The weight is 1.6 kg (3.55 lb) without velocity sensor or fittings.

Product Support & Availability

The Bently Nevada 21128-04-01 is in stock and ready to ship. Contact Petro Auto Tech for current lifecycle status, pricing, and availability. Our team can help you select the right housing for your application.