TG-F2388-E00

1st edition Aug 2023 K

OUTLINE

The UL330R “Time-Flight” type clamp-on ultrasonic flowmeter

measures flow rates in plastic piping (PVC, PE) ranging from 25

to 300 mm in nominal diameter and stainless steel piping ranging

from 25 to 400 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 flowmeter.

FEATURES

❏

The sensor of the UL330R ultrasonic flowmeter is clamped on

just outside of an existing pipe without requiring any piping

modification.

❏

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

conductivity 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.

MEASUREMENT PRINCIPLE

As shown in Fig. 1, when the ultrasonic wave is propagated in

the fluid in

ψ angle, there is the difference in propagation time

between A to B and the reverse direction. The propagation time

for each direction is calculated by the following formula.

tAB = 2L / VAB = 2L / (Co + Vm∙ COS

ψ)

tBA = 2L / VBA = 2L / (Co – Vm∙ COS

ψ)

Where,

2L

: Distance between A and B

Vm

: Average fluid velocity

Co

: Ultrasonic propagation velocity in resting state of

fluid

tAB, tBA : Ultrasonic propagation time between A to B and

B to A

VAB, VBA : Ultrasonic propagation velocity A to B and B to A.

ψ

: Propagation angle of the ultrasonic wave

Clamp-on Type

UL330R

Ultrasonic Flowmeter

The average fluid velocity (Vm) can be calculated by measuring the

difference in the propagation time as follows:

2Vm ∙ COS

ψ = 2L / tAB – 2L / tBA

ψ = 2L (tBA – tAB) / (tBA × tAB)

Hence, Vm = L (tBA – tAB) / (COS

ψ × tBA × tAB)

Since the distance (2L) between A to B and the angle

ψ are known,

the average fluid velocity (Vm) can be calculated. The flow rate can

be calculated from the above Vm and the cross-sectional area of

pipe, displayed and outputted.

A

B

Vm

VBA

VAB

L

Fig. 1 Measurement Principle