Prosonic 91 Ultrasonic Flowmeter Installation Guide

Correct installation is the key to ensuring the measurement accuracy of the Prosonic 91 ultrasonic flowmeter. This article provides a detailed introduction to the installation position, installation orientation, upstream and downstream straight pipe length requirements, as well as sensor selection and installation positions, helping you standardize the installation process.

1. Installation Position

A full pipe state in the measuring pipe at the installation position is the prerequisite for correct flowmeter measurement. Install the sensors on an upward pipe whenever possible.

Note! Gas accumulation or bubble formation in the measuring pipe will increase measurement error. Therefore, avoid the following installation positions in the pipe:

  • The highest point of the pipe. Gas easily accumulates here.
  • Directly above a downward draining pipe. A non-full pipe state easily occurs.

2. Installation Orientation

Vertical pipe: When sensors need to be installed on a vertical pipe, it is recommended to choose a pipe with fluid flowing from bottom to top (View A). With this installation orientation, when the fluid in the pipe is stationary, entrained solid media will settle and gas will rise, away from the sensors. The pipe can be completely self-draining, and solid adhesion will not occur.

Horizontal pipe: When sensors need to be installed on a horizontal pipe, it is recommended to install them in the area shown in (View B) to avoid the influence of gas and air accumulation at the top of the pipe and sediment at the bottom of the pipe on measurement.

  • A Recommended installation orientation, in which the fluid flows upward
  • B Recommended installation range in a horizontal pipe
  • C Recommended installation angle, max. 120°

3. Upstream and Downstream Straight Pipe Lengths

If possible, the sensor installation position should preferably avoid pipe fittings such as valves, tees, and elbows. When two or more disturbance sources exist, the recommended upstream and downstream straight pipe lengths for the strongest disturbance source should be observed.

It is recommended to ensure the following upstream and downstream straight pipe lengths to ensure compliance with measurement accuracy specifications.

4. Sensor Selection and Installation Position

1. Installation Path

Generally, the following two sensor installation positions are used:

  • Sensor installation position for single-path measurement: The two sensors are installed on opposite sides of the pipe.
  • Sensor installation position for dual-path measurement: The two sensors are installed on the same side of the pipe.

Top view of sensor installation positions:

  1. Sensor installation position for single-path measurement
  2. Sensor installation position for dual-path measurement

2. Sensor Installation Methods

The number of paths for acoustic signal propagation depends on the sensor type, nominal pipe diameter, and pipe wall thickness. The following sensor installation methods are recommended:

  1. For clamp-on sensors, the dual-path measurement installation position is recommended. The dual-path measurement installation position is the simplest and most appropriate installation method. Even if operation is only allowed on one side of the pipe, the entire measurement system can still be installed. However, under certain specific operating conditions, the single-path measurement installation position is more suitable for the sensors. For example:
    • Some plastic pipes with wall thickness > 4 mm (0.16")
    • Lined pipes
    • Measurement of acoustically damped fluids
  2. For composite material pipes (e.g., GRP), some lined pipes, pipes with wall thickness > 10 mm (0.4"), or when flow measurement of fluids with heavy acoustic damping is required, sensors with an operating frequency of 0.5 MHz are recommended. In this case, the W-type sensor installation position for single-path measurement is recommended.
  3. Sensors with an operating frequency of 6 MHz are suitable for flow velocity (the original text is incomplete here; it is recommended to supplement the complete content).