21128-03-02 | Bently Nevada 1/2-in NPT Velocity Transducer Housing

What Is the 21128-03-02?

When environmental hazards threaten velocity sensor performance, the 21128-03-02 from Bently Nevada provides reliable protection. This velocity transducer housing shields sensors from hose-directed water, corrosion, physical abuse, and adverse conditions. Constructed from 303 stainless steel, it meets NEMA 4X and IP65 requirements when properly installed. The housing is preferred for most non-hazardous environmental conditions.

Key Features & Technical Specs

• Mounting Thread and Cap Option: 1/2-in 14 NPT
• Cable Exit Fitting: 1/2-in NPT explosion-proof fitting
• 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
• Weight: 1.6 kg (3.55 lb) without sensor or fittings
• Internal Mounting Thread: 1/2-in 20 UNF
• Outlet Port Size: 1/2-in NPT

One distinctive spec is the wide temperature range of -29°C to +121°C. This ensures reliable operation in extreme industrial environments, from freezing outdoor conditions to high-heat machinery areas.

Industry Applications

Engineers use the 21128-03-02 in applications where velocity sensors must endure moisture, corrosion, or physical impact. For example, in pulp and paper mills, water spray from cleaning operations can damage unprotected sensors. This housing prevents such failures. Similarly, in mining operations, dust and debris are common threats. The stainless steel construction and IP65 rating provide a robust barrier. Because of its NEMA 4X compliance, it suits outdoor installations exposed to rain or washdowns.

Installation Guide

Proper installation is crucial for achieving the IP65 rating. First, ensure the housing is correctly mounted using the 1/2-in 14 NPT thread. Use the 1/2-in NPT explosion-proof fitting for cable exit. When installing a Velomitor CT sensor, the tall cap option is required. The same applies for 9200 or 74712 Seismoprobe sensors with isolated bases. Always follow the manufacturer's manual for torque specifications and sealing procedures.

Maintenance & Reliability

Regular inspection of the neoprene O-ring is essential. Over time, O-rings can degrade, compromising the seal. Check for cracks or deformation annually. Because the housing is not submersible, avoid prolonged immersion. Clean the exterior with a damp cloth; do not use abrasive cleaners. This routine care extends service life and maintains the IP65 integrity.

Compatible Systems

The 21128-03-02 works with Bently Nevada velocity sensors, including the Velomitor CT. For connecting the sensor to a monitor, cable part number 89477-AA is necessary. The housing also accommodates 9200 and 74712 Seismoprobe sensors with isolated bases when using the tall cap option. For explosion-proof needs, the CA21128 version is CSA certified for hazardous locations.

FAQs about 21128-03-02

What is the temperature range of the 21128-03-02?

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

Is the 21128-03-02 submersible?

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

What material is the O-ring made of?

The O-ring material is neoprene.

What cable is needed for connecting a Velomitor sensor?

Cable part number 89477-AA is necessary to connect the Velomitor sensor to a monitor.

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

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

Product Support & Availability

The 21128-03-02 is in stock and ready to ship. Contact Petro Auto Tech for current pricing and availability. Our team can assist with any technical questions regarding installation or compatibility.