21128-02-03 | Bently Nevada 3/4-in NPT Velocity Transducer Housing

Introduction to the 21128-02-03 Velocity Transducer Housing

When environmental hazards threaten sensor reliability, the 21128-02-03 from Bently Nevada provides robust protection. This velocity transducer housing, constructed from 303 stainless steel, shields sensors from hose-directed water, corrosion, and physical abuse. Its cost-effective design reduces downtime and replacement expenses in non-hazardous areas.

Key Features and Technical Specs of the 21128-02-03

• Mounting thread and cap option: 3/4-in 14 NPT.
• Cable exit fitting: 1/2-in NPT, explosion-proof with cable grip.
• Temperature rating: -29°C to +121°C (-20°F to +250°F).
• Moisture resistant but not submersible.
• O-ring material: Neoprene for reliable sealing.
• Weight: 1.6 kg (3.55 lb) without sensor or fittings.
• Internal mounting thread: 1/2-in 20 UNF (21128 and CA21128).
• Meets NEMA 4X and IP65 when properly installed.

The 3/4-in NPT mounting thread simplifies installation, cutting labor costs. The neoprene O-ring ensures long-term sealing, reducing maintenance frequency.

Real-World Applications for the 21128-02-03

In rotating machinery monitoring, the 21128-02-03 protects velocity sensors in pumps, fans, and compressors. Its corrosion resistance suits chemical processing plants, while the IP65 rating handles washdown environments. For explosion-proof needs, the CA21128 variant is available with CSA certification.

Installation and Setup Guidance

Mount the housing using the 3/4-in 14 NPT thread. Use a 1/2-in NPT cable fitting for the outlet. Ensure proper sealing to maintain NEMA 4X and IP65 ratings. For Velomitor CT sensors, order the tall cap option. Cable part number 89477-AA connects the sensor to the monitor.

Maintenance and Long-Term Reliability

Inspect the neoprene O-ring annually for wear. Replace if cracked or compressed. Check cable fittings for tightness to prevent moisture ingress. This low-maintenance design extends service life, lowering total ownership cost.

Compatibility and Integration

The 21128-02-03 accepts Bently Nevada velocity sensors like the Velomitor CT, 9200, and 74712 Seismoprobe. For BASEEFA-approved installations, use the BA42608 housing. The tall cap option accommodates isolated-base sensors.

Troubleshooting Common Issues

If moisture enters the housing, verify O-ring condition and cable fitting tightness. For signal loss, check the 89477-AA cable connection. Ensure the internal mounting thread matches the sensor (1/2-in 20 UNF for 21128).

Frequently Asked Questions about the 21128-02-03

Q: What is the temperature range for the 21128-02-03?

A: The housing operates from -29°C to +121°C (-20°F to +250°F).

Q: Is the 21128-02-03 submersible?

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

Q: What cable is needed for the Velomitor CT sensor?

A: Use cable part number 89477-AA to connect the sensor to the monitor.

Q: What is the weight of the 21128-02-03?

A: It weighs 1.6 kg (3.55 lb) without the sensor or fittings.

Q: Does the 21128-02-03 require a special cap for certain sensors?

A: Yes, a tall cap option is required for Velomitor CT or isolated-base 9200/74712 sensors.

Product Support and Availability

The 21128-02-03 is in stock and ready to ship from Petro Auto Tech. Contact our team for pricing and lead times. Please verify current lifecycle status before ordering.