OUTLINE

Our clamp-on type Ultrasonic Flowmeter UL350 has enabled ap-

plications to piping in various kinds by enhancing the permeation

property of ultrasonic wave. “Time-Flight” type flowmeter is capable

of measuring a flow rate of metallic and plastic piping ranging from

25 to 1000 mm in nominal diameter.

A detector (an ultrasonic sensor) is mounted outside an existing

piping by clamping method, so that it does not get into contact

with the measuring fluid at all, and there are no concerns about the

mixture of solid material and metallic ion into the fluid, the corrosion

of sensor by chemical, and the pressure loss by installing the flow-

meter.

FEATURES

❏ The sensor of ultrasonic flowmeter UL350 is clamped on just

outside of an existing pipe without any piping modification and

time consuming installation work.

❏ By adopting a DSP and an AD converters, the flow measurement

has been speeded up, and the resistance to bubbles has been

improved.

❏ Because of the noncontact measurement method, the formation

of bubbles and the mixture of metallic ion have been completely

prevented.

❏ Installing the flowmeter does not cause the pressure loss

because of no obstacles in the measuring pipe.

❏ The ultrasonic flowmeter is not affected by the pressure or con-

ductivity of fluids.

❏ Excellent in long-term stability because of no moving part.

❏ Providing the following functions: Forward/backward flow rate

display, totalizing display, analog output, pulse output, status

output.

❏ Capable of controlling the flow rate with digital data by RS-485

serial output. (Forward/backward flow rate output, totalizing

output, and status output by the Modbus protocol)

❏ A multi-drop connecting method has greatly reduced the signal

wire.

❏ Complied with RoHS. Applying for EMC standards.

MEASUREMENT PRINCIPLE

CLAMP-ON TYPE

UL350

ULTRASONIC FLOWMETER

As shown in Fig. 1, an ultrasonic is transferred from A to B and B to

A in turn with a angle of

ψ. The required durations of transfer of two

directions are different when measuring medium is moving from up

stream to down stream. The durations of transfer are expressed by

the following formula.

tAB = L / (Co + Vm COS

ψ)

tBA = L / (Co – Vm COS

ψ)

Where

L

:Distance between A and B

Vm

:Average velocity of medium

Co

:Sonic speed in stable medium

tAB, tBA :Duration of transfer of Ultra Sonic from A to B and B to A

By measuring the difference of the transfer duration, the average

velocity of medium can be calculated. The calculation is done by

the following formula:

2Vm cos

ψ = L / tAB – L/tBA

ψ = L (tBA – tAB) / (tBA × tAB)

Vm = L (tBA – tAB) / (2cos

ψ × tBA × tAB)

The distance between A and B (L) and the angle (

ψ) are known, and

the average velocity is mathematically calculated.

B

Vm

VBA

VBA

L

A

A

B

Ψ

Fig. 1

TG-F2334-E00

1st edition Dec 2022 K