Handheld flow meter TDS-100H

  1. HANDHELD ULTRASONIC FLOW METER

The TDS-100H ultrasonic flow meter is designed to measure the fluid velocity of liquid within a closed conduit.  The transducers are a non-contacting, clamp-on type, which will provide benefits of non-fouling operation and easy installation.

The TDS-100H transit time flow meter utilizes two transducers that function as both ultrasonic transmitters and receivers. The transducers are clamped on the outside of a closed pipe at a specific distance from each other.  The transducers can be mounted in V-method where the sound transverses the pipe twice, or W-method where the sound transverses the pipe four times, or in Z-method where the transducers are mounted on opposite sides of the pipe and the sound crosses the pipe once.  This selection of the mounting method depends on pipe and liquid characteristics.  The flow meter operates by alternately transmitting and receiving a frequency modulated burst of sound energy between the two transducers and measuring the transit time that it takes for sound to travel between the two transducers.  The difference in the transit time measured is directly and exactly related to the velocity of the liquid in the pipe

2. Features
3. Drawings
4. Sensors for selection
5. Transducers Installation

The transducers used by the TDS-100 series ultrasonic flow meter are made of piezoelectric crystals both for transmitting and receiving ultrasonic signals through the wall of liquid piping system. The measurement is realized by measuring the traveling time difference of the ultrasonic signals. Since the difference is very small, the spacing and the alignment of the transducers are critical factors to the accuracy of the measurement and the performance of the system. Meticulous care should be taken for the installation of the transducers.

Steps to the installation of the transducers
(1) Locate an optimum position where the straight pipe length is sufficient, and where pipes are in a favorable condition, e.g., newer pipes with no rust and ease of operation.
(2) Clean any dust and rust. For a better result, polishing the pipe with a sander is strongly recommended.
(3) Apply adequate coupler to the spot where the transducers are to be installed and leave no gap between the pipe surface and the transducers.

NOTICE:Extra care should be taken to avoid any sand or dust particles left between the pipe outer surface and the transducers.

To avoid gas bubbles inside the upper part of the pipe, the transducers should be installed horizontally by the side of the pipe.

§5.1 Transducers Spacing
The spacing value shown on menu window M25 refers to the distance of inner spacing between the two transducers. The actual transducers spacing should be as close as possible to the spacing value.

§5.2 V-method Installation
V-method installation is the most widely used mode for daily measurement with pipe inner diameters ranging from 20 millimeter to 300 millimeter. It is also called reflective mode or method.