CAT.No.CBD140E-1

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Transmitter   Standard Type Insertion Type

■ A thermistor element which has great low flowrate
sensitivity uses as the vortex detection element■ Simple structure with high durability■ Easy maintenance■ The transmitter can install in an easily manageable location■ Energy-saving designIt is a type of vortex flowmeter that uses the regularity and periodicity of theKarman vortex street. The thermistor sensor detects flow velocity changes
caused by the vortex generation to measure flowrate.
A thermistor element which has great low flowrate sensitivity uses as the vortex
detection element
The thermistor type has better low flowrate sensitivity than piezoelectric element type and is not affected by vibrationin principle.

Simple structure with high durability

Since there are no mechanical moving parts or wear parts, it has sufficient durability for a long term continuous use
and the accuracy does not change.

Easy maintenance
The standard type and insertion type (hot-tap type) have a sensor-replaceable structure that allows maintenance andinspection work to be performed without stopping the flow of the measurement fluid.

The transmitter can install in an easily manageable location

Since the transmitter separates from the main body, it can install freely in an easy-to-manage location and is
not affected by plumbing conditions.

Energy-saving design

Energy-saving flowmeter with low pressure loss

STANDARD TYPESTANDARD TYPEDOUBLE SENSOR•Measuring the actual flowrate, it
is not affected by changes intemperature, pressure, andphysical property of the fluid.

•Double instrumentation improvesmaintainability and safety.

•Accumulating the flowrate iseasy because pulse output is
proportional to the flowrate.

INSERTION TYPEINSERTION TYPE FOR
EXHAUST GAS MEASUREMENT•Large diameter is supported.

•Large diameter is supported.

•Less expensive than thestandard type with the samediameter.

Fixed Type•The sensor gas purge type iscapable of measuring hightemperature gas (up to 350℃).

Hot-tap Type

Purge box

Purge gas plumbing

GAS PURGE TYPE
•This type replaces the flow velocity changes caused by the vortex
generation in the line flow with the flow velocity changes of purgegas (dry clean gas) which is introduced from the outside.
The thermistor sensor is constantly in contact with clean and room
temperature purge gas, so it is capable of measuring gas which
was difficult to measure so far such as gas containing dust andmist also, high and low temperature gas.

■ APPLICATION EXAMPLESLNG terminal

Power plant

Return gas
For control
Vaporizer

LNG
undergroundtank

For transaction
Steel mills and chemical plants(near LNG terminal)

For transaction

Gas company

High pressure pipelines(1 to 7MPa)

High pressure trunk pipeline(remote area)

For transactionOdorizer

Remote area
Gas company

Calorific valueadjustment

Remote area
Power company
High pressure
governor

For transaction(shipping)

Factory■ MEASUREMENT PRINCIPLE
When a fluid flows in a pipe, a Karman vortex proportional to the flow velocity generates downstream of a bluff
body which placed at right angles to the fluid flow. The flow velocity changes caused by the vortex generation
is extracted from the thermistor sensor in the sensor housing as temperature change → resistance change →flow velocity proportional pulse to measure the flowrate.
Transmitter (PA21)

Bluff body

Karman vortex

Constant
current
circuit

Thermistor sensor
FilterBlock valve
Bypass inlet

PowersourcePowersupplySensor housing
Block valve

Sensor voltage
control circuit
CPU

Bypass outlet
Bluff bodyHighsensitive
amplifier

A/D
Converter

Sensor
Detector

Pulse output

■GENERAL SPECIFICATIONS (For details, please refer to the General Specification sheet of each model.)Description
ItemStandard Type

Wafer type

Nominal size

20 to 150mm

Flange type

Standard TypeDouble sensor

Gas Purge Type

40 to 150mm

50 to 150mm

Insertion Typefor Exhaust Gas Measurement

Insertion Type̶200 to 500mm

̶Applicable pipeline diameter̶

200 to 2000mm

Installation

̶

Fixed Type
Hot-tap Type

Fixed Type

−10 to +120℃(Option: −20 to +130℃)−10 to +80℃

−10 to +80℃
(Gas-purge type withcooling fins −10 to +350℃)

Operating temperature range
Maximum operating pressure

Less than 1MPa

Depends on flange standard

Accuracy

Within ±2% of full scale

Within ±1% of reading or ±1% of full scale

Applicable fluid

Air, City gas, Natural gas

Air, NitrogenAir, Nitrogen, City gas

Air, Various exhaust gases

Horizontal

No restriction regarding
meter accuracy.
Typically horizontal.

̶̶DC power supply

Power supply
OutputPulse, Status

Reproducibility

Within ±0.2%
Horizontal or vertical

Physical orientation

̶Purge gas

̶

For instrumentation air,nitrogen, or the same gas
as the measurement fluid■CONNECTION TO RECEIVING INSTRUMENTS (EXAMPLE)● Line temperature and pressure are considered approximately constant and correction coefficient can be multiplied as a fixed constant:Meter body

Transmitter

Totalizer (EL0122)
Display Total andInstantaneous Flowrate

Pulse Distributor (SU1508)
orExternal Power Source● Flowrate is corrected automatically by using the line temperature and pressure, and display (or output) total and instantaneous flowrate:
Meter bodyTransmitter

4 to 20mADC

Unfactored Pulse

Factored Pulse

Pressure Transmitter

Flow Computer(EL4001 series)

Resistance Thermometer

The specification as of November, 2021 is stated in this catalog. Specifications and design are subject to change without notice.

3-10-8 Kamiochiai, Shinjuku-ku, Tokyo 161-8508
Phone: +81 3-3360-5121 FAX: +81 3-3365-8605

https://www.oval.co.jp/english
2111‐‐‐‐2111S