21128-14-02 | Bently Nevada 1/2-in NPT Velocity Transducer Housing

Case Study: Protecting Velocity Sensors in Harsh Environments

When a petrochemical plant faced frequent sensor failures due to hose-directed water and corrosive chemicals, engineers needed a robust solution. The 21128-14-02 from Bently Nevada provided the answer. This velocity transducer housing, constructed from 303 stainless steel, meets NEMA 4X and IP65 requirements when properly installed. It protects sensors from physical abuse and adverse conditions, ensuring reliable operation in demanding settings.

Key Features & Technical Specs of the 21128-14-02

• Material: 303 stainless steel for corrosion resistance.
• Temperature Rating: -29°C to +121°C (-20°F to +250°F).
• Moisture Protection: Resistant to moisture and corrosion, but not submersible.
• Mounting Thread: 1/2-in 14 BSP (G 1/2-in) with tall cap.
• Cable Exit: 1/2-in NPT explosion-proof fitting.
• Weight: 1.6 kg (3.55 lb) without velocity sensor or fittings.
• O-ring Material: Neoprene.
• Outlet Port Size: 1/2-in NPT.
• Internal Mounting Thread: 1/2-in 20 UNF.

One distinctive spec is the wide temperature range of -29°C to +121°C, which allows the housing to perform reliably in both freezing and high-heat industrial environments.

Industry Applications

This housing is ideal for non-hazardous environmental conditions where water, corrosion, or physical abuse is a concern. For example, in a steel mill, the 21128-14-02 protects velocity sensors from coolant sprays and metal debris. Additionally, it is suitable for chemical processing plants where corrosive atmospheres are present. The tall cap option enables installation of a Velomitor CT or other compatible sensors.

Installation Guide

To install the 21128-14-02, first ensure the housing is properly grounded and the cable exit fitting is tightened to prevent moisture ingress. Use cable part number 89477-AA to connect the Velomitor sensor to a monitor. The mounting thread is 1/2-in 14 BSP, so verify compatibility with your sensor. For explosion-proof installations, use the CA21128 version with CSA certification.

Maintenance & Reliability

Regularly inspect the neoprene O-ring for wear or damage to maintain the IP65 seal. Clean the housing exterior with a damp cloth to remove corrosive residues. Avoid submerging the housing, as it is not submersible. Following these steps extends service life and reduces downtime.

Compatibility & Integration

The 21128-14-02 is designed for Bently Nevada velocity sensors such as the Velomitor CT, 9200, or 74712 Seismoprobe. For the CA21128 explosion-proof version, it must be shipped with a CSA approved velocity sensor installed. The BA42608 housing is used for BASEEFA-approved installations requiring compliance with BS EN 60079 14.

Troubleshooting & Common Issues

If the housing fails to maintain its seal, check the O-ring for cracks or deformation. Ensure the cable exit fitting is properly tightened. For moisture ingress, verify the housing is not submerged and that the NEMA 4X rating is maintained. If using the tall cap, confirm the sensor fits correctly.

FAQ about 21128-14-02

Q: What is the temperature rating of the 21128-14-02?

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

Q: Is the 21128-14-02 submersible?

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

Q: What cable is needed for the 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 21128-14-02?

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

Q: What material is the O-ring made of?

A: The O-ring material is neoprene.

Product Support & Availability

The 21128-14-02 is in stock and ready to ship from Petro Auto Tech. Please verify current lifecycle status and availability with Petro Auto Tech before ordering.