Immersible ultrasonic transducer BBFM-V40K

Overview
The BBFM-V40K is an ultrasonic wind speed and direction transducer for 2D and 3D ultrasonic anemometers, meteorological monitoring, ventilation airflow measurement and industrial duct monitoring. Its center frequency is 40 kHz ±5% with a recommended reference range of 0.5 to 12 m and a -3 dB half-power beam angle of 11.3° ±10%. Consider path length and angular coverage when defining the measurement volume.

Verified technical specifications

• Model: BBFM-V40K
• Center frequency: 40 kHz ±5%
• Recommended/reference range: 0.5 to 12 m
• Minimum impedance: 250 Ω ±20%
• Capacitance: 4,000 pF ±20% at 1 kHz
• Maximum applied peak voltage: <1,500 Vpp
• Operating temperature: -40 to +80°C
• Pressure rating: ≤3 kgf / 0.3 MPa
• Half-power beam angle: 11.3° ±10% at -3 dB
• Housing material: Stainless steel
• Protection rating: IP68
• Weight: 1,580 g ±5% (with 10 m ±0.3 m cable)

Array layout and electrical matching
For 2D or 3D anemometers, locate paths within the 0.5–12 m reference range while accounting for the 11.3° beam angle, airflow geometry, structural obstructions and transducer alignment. Transmit and receive electronics should match the minimum impedance of 250 Ω ±20% and the capacitance of 4,000 pF ±20% at 1 kHz. Applied peak voltage must remain below 1,500 Vpp.

Mechanical and environmental integration
Operation is specified from -40 to +80°C, up to 3 kgf (0.3 MPa), and with IP68 protection. The listed weight applies to the configuration with a 10 m ±0.3 m cable; plan supports, mounting and cable routing accordingly.

Applications

• 2D and 3D ultrasonic anemometers
• Meteorological monitoring
• Ventilation airflow measurement
• Industrial duct monitoring