YOKOGAWA VY Series User manual

User’s
Manual Vortex Flowmeter
VY Series
Maintenance Manual
IM 01F07A01-02EN
IM 01F07A01-02EN
1st Edition

1
IM 01F07A01-02EN
Vortex Flowmeter VY Series
Maintenance Manual
IM 01F07A01-02EN 1st Edition
Contents
1. INTRODUCTION............................................................................................2
1.1 Using This Instrument Safely ............................................................................. 5
1.2 Warranty................................................................................................................ 6
2. HANDLING PRECAUTIONS.........................................................................7
2.1 CheckingModelandSpecications .................................................................. 7
2.2 Transportation and Storage Precautions.......................................................... 8
3. MAINTENANCE.............................................................................................9
3.1 Changing the Orientation of the Transmitter Case and
Sensor Terminal Box ........................................................................................... 9
3.2 Removing and Rotating the Indicator.............................................................. 10
3.3 RemovingtheAmplierUnit............................................................................. 12
3.4 InstallingtheAmplierUnit .............................................................................. 13
3.5 Removing and Installing the Shedder Bar ...................................................... 14
3.6 Replacing the Lightning Protector Module..................................................... 17
3.7 Calculation Formulas ........................................................................................ 18
Revision Information ........................................................................................... 21
1st Edition: Feb. 2022
All Rights Reserved, Copyright © 2022, Yokogawa Electric Corporation

<1. Introduction> 2
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1. INTRODUCTION
Thank you for purchasing a VY Series Vortex Flowmeter. This manual describes maintenance
procedures for VY Series Vortex Flowmeters. You can refer to the related manuals for this
instrument listed in Table 1.1 in the Vortex Flowmeter VY Series Installation Manual (IM
01F07A01-01EN). Manuals for each product can be downloaded from the Yokogawa website. Be
sure to read these manuals to ensure correct use of the products.
Website address:
https://www.yokogawa.com/library/
Regarding This Manual
• This manual should be provided to the end user.
• The contents of this manual may be changed without prior notice.
• All rights are reserved. No part of this manual may be reproduced in any form without
Yokogawa's written permission.
• Yokogawa makes no warranty of any kind with regard to this material, including, but not
limited to, implied warranties of merchantability and suitability for a particular purpose.
• All reasonable e󰀨ort has been made to ensure the accuracy of the contents of this manual.
However, if any errors or omissions are found, please inform Yokogawa.
• The specications covered by this manual are limited to those for the standard type under
the specied model number break-down and do not cover custom-made instruments.
• Please note that this manual may not be revised for any specication changes,
construction changes or operating part changes that are not considered to a󰀨ect function or
performance.
• Yokogawa assumes no responsibilities for this product except as stated in the warranty.
• If the customer or any third party is harmed by the use of this product, Yokogawa assumes
no responsibility for any such harm owing to any defects in the product which were not
predictable, or for any indirect damages.
SafetyandModicationPrecautions
• When handling this instrument, follow the safety precautions described in this document
for protection and safety of personnel, this instrument and systems that incorporate this
instrument. Yokogawa does not guarantee the safety of this instrument if the customer has
failed to comply with these precautions.
• Modication of the product in question without the authorization of Yokogawa is strictly
forbidden.
• When an explosion protected type instrument has been repaired or modied by the
customer and cannot be restored to its original condition, the explosion protective structure
of this instrument will be impaired and a hazardous condition will arise. Be sure to consult
Yokogawa regarding repairs and modications.

<1. Introduction> 3
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The following safety symbol marks are used on this product and in this manual.
WARNING
A WARNING sign denotes a hazard. It calls attention to procedure, practice, condition or the like,
which, if not correctly performed or adhered to, could result in injury or death of personnel. This
document presents precautions for avoiding such hazards should such a situation arise.
CAUTION
A CAUTION sign denotes a hazard. It calls attention to procedure, practice, condition or the
like, which, if not correctly performed or adhered to, could result in damage to or destruction of
the product. This document presents precautions for avoiding such hazards should there be a
physical risk to the user's well-being or damage to equipment.
IMPORTANT
An IMPORTANT sign denotes that attention is required to avoid damage to the instrument or
system failure.
NOTE
A NOTE sign denotes information necessary for essential understanding of operation and
features.
Various symbols are marked on the instrument itself. The meanings of these symbols are as
follows.
Functional ground terminal
Direct current
Handling precaution
This is attached to locations where this manual must be referenced to protect personnel
safety and devices.
• When handling this instrument, follow the safety precautions described in this document
and other precautions for the protection and safety of this instrument and systems that
incorporate this product. When these precautions are not complied with, the protection
functions of this instrument may be impaired or instrument functions may not be fully
demonstrated. In this case, Yokogawa makes no guarantee whatsoever for the quality,
performance, functions, and safety of the product.
• When performing the installation of protective and safety circuits for this instrument or
control systems, such as lightning protection systems or devices on this instrument or on
systems controlled by this instrument, or the foolproof or failsafe design of processes and
lines that use this instrument or control systems, and the design and installation of other
protective and safety circuits, the customer should implement this appropriately at their own
judgment. Also, the customer should separately consider achieving the above by devices
other than this instrument, and prepare devices accordingly.

<1. Introduction> 4
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• When replacing the parts of this instrument, be sure to use only parts specied by
Yokogawa.
• This product is not designed or manufactured to be used in critical applications that directly
a󰀨ect or threaten human lives. Such applications include nuclear power equipment, devices
using radioactivity, railway facilities, aviation equipment, air navigation facilities, aviation
facilities, and medical equipment. If so used, it is the user’s responsibility to include in the
system additional equipment and devices that ensure personnel safety.
• Modication of this instrument is strictly forbidden.
• If this instrument is modied or replaced, each explosion protection accreditation is
invalidated.
• This instrument should be disposed of in accordance with local and national legislation/
regulations.
Table 1.1 Related Documents
Document title Document No.
Vortex Flowmeter VY Series GS 01F07A00-01EN
FSA130 Magnetic Flowmeter/Vortex Flowmeter Verication Tool GS 01E21A04-01EN
Vortex Flowmeter VY Series Read Me First
Vortex Flowmeter VY Read Me First IM 01F07A21-01Z1
Vortex Flowmeter VY Series Safety Manual IM 01F07A21-02EN
Vortex Flowmeter VY Series Installation Manual IM 01F07A01-01EN
Vortex Flowmeter VY Series Maintenance Manual IM 01F07A01-02EN
Vortex Flowmeter VY Series HART Communication Manual IM 01F07A02-01EN
Vortex Flowmeter VY Series Verication Tool IM 01F07A04-01EN
Vortex Flowmeter VY Series FM (USA) Explosion Protection Type IM 01F07A03-01EN
Vortex Flowmeter VY Series FM (Canada) Explosion Protection Type IM 01F07A03-02EN
Vortex Flowmeter VY Series ATEX Explosion Protection Type IM 01F07A03-03EN
Vortex Flowmeter VY Series IECEx Explosion Protection Type IM 01F07A03-04EN

<1. Introduction> 5
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1.1 Using This Instrument Safely
(1) Maintenance
WARNING
• Maintenance of the vortex owmeter should be performed by trained personnel with
knowledge of safety. No operator shall be permitted to perform any operations relating to
maintenance.
• Do not open the cover in wet weather or humid environments. When the cover is opened, the
stated enclosure protection is not applicable.
• For details on maintenance, read the maintenance manual in the related documents indicated
in Table 1.1. Perform only maintenance that is described in this manual. Do not perform other
maintenance. If other maintenance is necessary, contact your nearest sales o󰀩ce or Service
Center.
• When opening and closing the cover, pay su󰀩cient care to handling of screws and O-rings to
prevent damage and attachment of foreign objects.
• Some of the electronic components used on this product are susceptible to damage as a
result of static electricity. Take su󰀩cient care when handling electronic components by, for
example, wearing wrist straps to prevent charging by static electricity and not directly touching
electronic components, circuits and other components susceptible to static electricity.
(2) Modication
Yokogawa will not be liable for malfunctions or damage resulting from any modication made to
this instrument by the customer.
(3) Product Disposal
The instrument should be disposed of in accordance with local and national legislation/
regulations.
(4) Authorized Representative in EEA
In relation to the CE Marking, The authorized representative for this product in the EEA
(European Economic Area) is: Yokogawa Europe B.V. Euroweg 2,
3825 HD Amersfoort, The Netherlands
(5) CE Marking
CE marking is displayed on the nameplate for non-explosion protected type devices and ATEX
explosion protected type devices. Products with CE marking are in compliance with the statutory
requirements of the applicable EU directives.
*VY150 with nickel alloy CW-12MW body material is not compliant with PED, so the CE marking is not displayed.
(6) EU RoHS Directive
EN IEC 63000:2018
(7) Morocco Conformity Mark
This conformity mark indicates that the product complies with Moroccan requirements.

<1. Introduction> 6
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1.2 Warranty
• The terms of this instrument that are guaranteed are described in the quotation. We will
make any repairs that may become necessary during the guaranteed term free of charge.
• Please contact our sales o󰀩ce if this instrument requires repair.
• If the instrument is faulty, contact us with concrete details about the problem and the length
of time it has been faulty, and state the model and serial number. We would appreciate the
inclusion of drawings or additional information.
• The results of our examination will determine whether the owmeter will be repaired free of
charge or on an at-cost basis.
The guarantee will not apply in the following cases:
• Damage due to negligence or insu󰀩cient maintenance on the part of the customer.
• Problems or damage resulting from handling, operation or storage that violates the intended
use and specications.
• Problems that result from using or performing maintenance on the instrument in a location
that does not comply with the installation location specied by Yokogawa.
• Problems or damage resulting from inappropriate re-installation after delivery.
• Problems or damage resulting from disasters such as res, earthquakes, storms, oods, or
lightning strikes and external causes.
• Problems or damage resulting from repairs or modications not performed by Yokogawa or
someone authorized by Yokogawa.
Trademarks
• "HART" is the registered trademark of FieldComm Group.
• All the brands or names of Yokogawa Electric's products used in this manual are either
trademarks or registered trademarks of Yokogawa Electric Corporation.
• Product names and company names in this document are trademarks or registered
trademarks of the respective companies.
• In this document, trademarks or registered trademarks are not marked with "™" or "®".

<2. Handling Precautions> 7
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2. HANDLING PRECAUTIONS
This section describes the precautions to follow when handling the product. Be sure to read this
section before using the product. For information other than that described in this section, refer to
the related section.
If you have any problems or questions, contact your nearest YOKOGAWA service center or sales
representative.
2.1 CheckingModelandSpecications
This instrument is inspected thoroughly before it is shipped from the factory. When this
instrument is delivered to the installation site, check its external appearance for damage, and
make sure that all parts for installation are provided.
Be sure that you have your model number (MODEL) and serial number (No.) available when
contacting Yokogawa.
The model code and specications given on the nameplate are those current when this product
was shipped from the factory. It is not possible to change the nameplate after shipment.
F0201.ai
Figure 2.1(a) Example of Nameplate (Integral Type)
Remote sensor
F0202.ai
Remote transmitter
F0205.ai
Figure 2.1(b) Example of Nameplate (Remote Type)

<2. Handling Precautions> 8
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2.2 Transportation and Storage Precautions
To prevent damage to the vortex owmeter due to accidents during transportation, it should be
carried in its original packing condition.
Deterioration of insulation, corrosion or other abnormalities may occur due to unexpected
situations if the vortex owmeter is stored for a long period of time after it is delivered to the user
site. When it is anticipated that the vortex owmeter will be stored for a long time, pay attention to
the following points.
(1) The vortex owmeter should be stored in its original packing condition in the storage
location.
(2) Select a storage location that fullls the following conditions:
• A place where it will not be exposed to rain or water
• A place subject to minimal vibrations or shocks
• Temperature and humidity levels should be as follows: The preferred ambient temperature
and humidity levels are +25°C and approximately 65% RH.
Ambient temperature: -40 to +85°C
Humidity: 0 to 100% RH (no condensation)
(3) When storing a vortex owmeter after use, completely clean the owmeter to ensure that
there is no measured uid remaining in its piping line and on the shedder bar.
(4) If the vortex owmeter is carried to the installation site and is stored without being installed,
rain water might get inside and impair the instrument’s performance. Install, wire and
perform other installation work immediately after transporting the vortex owmeter to the
installation site.
(5) The vortex owmeter is a heavy instrument. When moving the vortex owmeter, always use
a trolley and have at least two people carry it.
When winching instruments, winch by the method shown in Figure 2.3.
Rain
Prevent water build up
Packing box
F0203.ai
Room temperature/pressure
is preferable Prevent from
being splashed
with water
Figure 2.2 Storage Site Precautions
F0204.ai
Figure 2.3 Winching Method

<3. Maintenance> 9
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3. MAINTENANCE
3.1 Changing the Orientation of the Transmitter
Case and Sensor Terminal Box
WARNING
• In the case of an explosion protected type instrument, make sure that no explosive
atmosphere conditions are present.
• When removing or installing the transmitter case, pay careful attention to the handling of
O-rings to prevent damage and adhesion of foreign matter.
• Replace O-rings if they are damaged or deformed.
• If there is no lubricant on the O-rings, apply silicone-based grease.
CAUTION
Repairs and modications to this instrument can only be performed at the Yokogawa factory.
The orientation of the transmitter case and sensor terminal box can be changed in 90-degree
increments (four directions). Follow the procedure below to change the orientation.
(1) Remove the hexagon socket head cap screw (4 places) that secure the transmitter case
and bracket.
(2) Rotate the case to the desired orientation.
To prevent strain on the internal cable, do not rotate the case more than 180 degrees at this
time.
Note: The orientation may have been specied when ordering the instrument. Check the
status of the internal cable while rotating the case.
(3) Tighten the hexagon socket head cap screw with the case in the desired orientation.
(Tightening torque: 3 N·m)
F0301.ai
Figure 3.1 Changing the Orientation of the Transmitter Case and Sensor Terminal Box

<3. Maintenance> 10
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3.2 Removing and Rotating the Indicator
IMPORTANT
In the case of an explosion protected type instrument, modication by the user is prohibited.
WARNING
• In the case of an explosion protected type instrument, make sure that no explosive
atmosphere conditions are present.
• When opening and closing the cover, pay careful attention to the handling of screws and
O-rings to prevent damage and adhesion of foreign matter.
• Replace O-rings if they are damaged or deformed.
• If there is no lubricant on the O-rings, apply silicone-based grease.
CAUTION
• In the case of an explosion protected type instrument, the covers and screws must be
returned to the original condition.
• In the case of a ameproof protected type instrument, turn the locking screws shown in Figure
3.2 to the right to unlock the cover before removing it. When installing the cover, make sure to
turn the locking screws to the left to lock the cover.
F0306.ai
Locking screw
(terminal box side)
Locking screw
(amplifier unit side)
Figure 3.2 Locking Screws

<3. Maintenance> 11
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Follow the procedure below to remove and rotate the indicator.
(1) Turn the power OFF.
(2) Remove the cover. When opening the cover of a ameproof type instrument, turn the
locking screws to the right to unlock the cover.
(3) Loosen the two indicator mounting screws.
(4) Pull the indicator out straight using your hands.
(5) Remove the screws and washers from the printed circuit board, then reinstall in the desired
position by tightening the screws and washers.
(6) When installing the indicator, perform the removal procedure in reverse to return the parts to
their original positions, then tighten the indicator mounting screws. The indicator installation
angle can be rotated in 90-degree increments.
(7) Install the cover. When installing the cover on a ameproof type instrument, make sure to
turn the locking screws to the left to lock the cover.
CAUTION
Pay attention not to break the connector pin, and make sure that the connector (male) of the
amplier unit and the connector (female) of the display unit are assembled correctly.
F0302.ai
Figure 3.3 Removing and Installing the Indicator

<3. Maintenance> 12
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3.3 RemovingtheAmplierUnit
IMPORTANT
Do not twist the amplier unit when removing or installing it. Doing so may damage the connector
pins.
WARNING
• In the case of an explosion protected type instrument, make sure that no explosive
atmosphere conditions are present.
• When opening and closing the cover, pay careful attention to the handling of screws and
O-rings to prevent damage and adhesion of foreign matter.
• Replace O-rings if they are damaged or deformed.
• If there is no lubricant on the O-rings, apply silicone-based grease.
Follow the procedure below to remove the amplier unit.
(1) Turn the power OFF.
(2) Remove the cover. When opening the cover of a ameproof type instrument, turn the
locking screws to the right to unlock the cover.
(3) Loosen the two amplier unit mounting screws with a 5.5 mm socket nut driver, and pull the
amplier unit out straight.
If the instrument is equipped with an indicator, remove the indicator before removing the
amplier unit. Follow the procedure described in Section 3.2 to remove the indicator.

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3.4 InstallingtheAmplierUnit
IMPORTANT
Make sure to follow the procedure below when installing the amplier unit.
The amplier unit may not function properly if it is installed without following the procedure exactly
as described.
Follow the procedure below to install the amplier unit.
(1) Place the amplier unit in the transmitter case so that the at side at the top of the amplier
unit ts against the at surface inside the transmitter case.
(2) Insert the ends of the two amplier unit mounting guide pins into the mounting holes.
(3) Lightly press the upper and lower parts of the amplier unit simultaneously to insert the
amplier unit into the transmitter case. Take care not to touch the electronic components of
the amplier unit when pressing it in.
(4) Tighten the amplier unit mounting screws to secure the amplier unit. If the instrument
is equipped with an indicator, follow the procedure described in Section 3.2 to install the
indicator.
(5) Install the cover. When installing the cover on a ameproof type instrument, make sure to
turn the locking screws to the left to lock the cover.
F0303.ai
Amplifier unit mounting guide pin
Figure3.4 RemovingandInstallingtheAmplierUnit

<3. Maintenance> 14
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3.5 Removing and Installing the Shedder Bar
IMPORTANT
• The accuracy is not guaranteed after removing and replacing the shedder bar.
If you require an accuracy guarantee, we recommend having the Yokogawa factory perform
shedder bar removal and replacement.
• Shedder bar replacement should be performed by trained personnel with knowledge of the
product characteristics and safety.
WARNING
• In the case of an explosion protected type instrument, make sure that no explosive
atmosphere conditions are present.
• Before removing the shedder bar, stop the ow and remove any remaining uid.
• When removing or installing the shedder bar, pay careful attention to the handling of the
transmitter case O-rings and shedder bar O-rings to prevent damage and adhesion of foreign
matter.
• Replace O-rings if they are damaged or deformed.
• If there is no lubricant on the O-rings, apply silicone-based grease.
• When replacing or removing the shedder bar, always replace the gasket with a new one.
CAUTION
If the shedder bar is not properly reinstalled after replacing or removing it, the readings may be
a󰀨ected when operation resumes.

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(1) Remove the four transmitter case mounting bolts shown in Figure 3.5, and remove the
transmitter case from the bracket.
F0304.ai
Transmitter case
mounting bolts
Bracket mounting
bolts
Shedder bar
mounting bolts
Sensor Cable
Gasket
Figure 3.5 Removing the Shedder Bar
CAUTION
The sensor cable is connected to the transmitter case. To prevent strain on the connector,
disconnect the sensor cable when the transmitter case is about 5 cm away from the bracket.
(2) Remove the two bracket mounting hexagon socket head cap screw that secure the bracket
to the instrument, and remove the bracket from the instrument while paying careful attention
to the sensor cable.
(3) Remove the shedder bar mounting bolts (2 to 10 bolts) and washers, then remove
the shedder bar xing block and shedder bar with attention to the sensor cable. The
instrument may not be equipped with the washers and shedder bar xing block due to the
specications.
(4) To assemble, perform steps (1) to (3) in reverse.
Fix the transmitter mounting hexagon socket head cap screw and the bracket mounting
hexagon socket head cap screw with the following torques.
Fix the bolts with the following torques:
3 N•m for transmitter case mounting bolts
13 N•m for bracket mounting bolts
a. Always replace the gasket with a new one.
Before assembling, make sure that no foreign matter is adhering to the seal surface that the
gasket makes contact with.
b.
Check that the uid ow direction and the direction of the shedder bar are as shown in Figure 3.7.

<3. Maintenance> 16
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c. Check that the pin of the shedder bar xing block is aligned with the pin hole of the shedder
bar as shown in Figure 3.6.
F0305.ai
Figure 3.6 Installing the Shedder Bar
F0307.ai
Upstream Downstream
Figure 3.7 Shedder Bar
Installation
Direction
d. Tighten the shedder bar xing bolts to the appropriate tightening torque value as shown in
Table 3.1 and Table 3.2. Partially tighten each bolt equally 3 to 4 times until the tightening
torque value is reached. Read Figure 3.8 for the bolt tightening sequence.
F1105.ai
Upstream
Number of bolts: 2
Number of bolts: 4 Number of bolts: 6
Upstream
Number of bolts: 10
Upstream
Upstream






 













Number of bolts: 8
Upstream







Figure 3.8 Bolt Tightening Sequence
CAUTION
Since the bolts are near the sensor, the readings may be a󰀨ected if the bolts are not evenly
tightened. Unevenly tightened bolts may also cause uid to leak. Make sure that the bolts are
tightened evenly to the appropriate tightening torque value.

<3. Maintenance> 17
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a. In the case of a high temperature type instrument with option code /SPG, tighten the bolts
once to tightening torque value A, then loosen the bolts and tighten them again to tightening
torque value B. When loosening the bolts, stop once they are partially loosened, and do not
loosen them completely.
Table 3.1 Tightening Torque Values
Model code/Type of body Tightening torque [N·m]
-0: General type
-1: Reduced
bore type
(1 size
reduction)
-2: Reduced
bore type
A, B: General
type,
E: Cryogenic
type
C, D: High temperature
type,
/SPG
A B
VY015-0 VY025-1 VY040-2 16 16 *1 16 *1
VY025-0 VY040-1 VY050-2 12 18 12
VY040-0 VY050-1 VY080-2 12 18 12
VY050-0 VY080-1 VY100-2 12 *2 18 *2 12 *2
18 *3 27 *3 18 *3
VY080-0 VY100-1 VY150-2 21 *2 32 *2 21 *2
32 *3 48 *3 32 *3
VY100-0 VY150-1 VY200-2 21 *2 32 *2 21 *2
49 *3 74 *3 49 *3
VY150-0 VY200-1 ----- 69 98 69
VY200-0 ----- ----- 69 98 69
VY250-0 ----- ----- 157 210 140
VY300-0 ----- ----- 157 210 140
VY400-0 ----- ----- 160 240 140
*1: For /SPG (stainless steel gasket plated with silver) only
*2: For ASME/JPI Class 150, 300 JIS 10K, 20K, and EN PN 10, 16, 25, 40
*3: For ASME/JPI Class 600, 900, and JIS 40 K
Table 3.2 Tightening Torque Values (High Pressure Reduced Bore Type)
Model code/Type of body
Tightening torque [N·m]
-4: High pressure reduced bore type
(1 size reduction)
VY025-4 12
VY040-4 37
VY050-4 37
VY080-4 37
VY100-4 50
VY150-4 78
CAUTION
For instruments with custom specications, make sure to read the accompanying manual.
b. After replacing the shedder bar, take care not to damage the sensor cable when installing
the bracket and transmitter case.
c. After assembly, make sure that no uid leaks from the vortex owmeter.
3.6 Replacing the Lightning Protector Module
For details on replacing the lightning protector module, read the Vortex Flowmeter VY Series
Installation Manual listed in the related documents in Table 1.1.

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3.7 Calculation Formulas
(1) Flow rate calculation
The ow rate is calculated based on the following formulas, where N is the count number of
generated vortices.
a)Instantaneousowrate(actualowrateunit)(RATE)
RATE = N×1 /∆t×εf×εe×εr×1 / KT×Uk×UTM
KT = KM×UKT / {1+Et (Tf-15)×10-5}
b)Instantaneousowrate(%)(RATE(%))
RATE (%) = RATE×1 / FS×100
c) Totalized value (TOTAL)
TOTAL = TOTAL+∆TOTAL
∆TOTAL = RATE×∆t×1 / TR×1 / UTM
d) Pulse output frequency (PULSE FREQ)
• For scaled pulse:
PULSE FREQ = RATE×1 / PR×1 / UTM
• For unscaled pulse (no unit calculation):
PULSE FREQ = N×1 /∆t×1 / PR
e) Flow velocity (V)
V = N×1 /∆t×1 / KT×UKT×4 / {π×D2}
f) Reynolds number (Re)
Re = V×D×ρf×1 /μ×1000
N: Number of input pulses (pulse)
∆t: Time corresponding to N (sec)
εf: Instrument error correction coe󰀩cient
εe: Compressible uid expansion correction coe󰀩cient
εr: Reynolds correction coe󰀩cient
KT: K factor for operating temperature (p/l)
KM: K factor at 15°C (p/l)
Et: Expansion coe󰀩cient
UKT: K factor unit conversion coe󰀩cient
Uk: Flow rate unit conversion coe󰀩cient (Read "(2) Flow rate unit conversion coe󰀩cient (Uk)"
below.)
UTM: Time unit conversion coe󰀩cient (example: /m (min) = 60)
PR: Pulse rate
Tf: Temperature at operating conditions (°C)
FS: Flow rate span
TR: Total rate
D: Inner diameter of vortex owmeter sensor section (mm)
μ: Viscosity coe󰀩cient (mPa·s)
ρf: Density at operating conditions (kg/m3)

<3. Maintenance> 19
IM 01F07A01-02EN
(2) Flowrateunitconversioncoe󰀩cient(Uk)
The ow rate conversion coe󰀩cient Uk is calculated according to the measured uid and
the selected ow rate unit, as indicated below.
a) Steam
For M (mass):
Uk = ρf×Uρf×Uk(kg)
For Qf (ow rate):
Uk= Uk(m3)
b) Gas
For Qn (ow rate):
Uk= {Pf/ Pn}×{(Tn+273.15) / (Tf+273.15)}×1 / K×Uk(Nm3)
For M (mass):
Uk = ρf×Uρf×Uk(kg)
For Qf (ow rate):
Uk= Uk(m3)
[Flow rate unit] N: Normal conditions
c) Liquid
For Qf (ow rate):
Uk= Uk(m3)
For M (mass):
Uk = ρf×Uρf×Uk(kg)
d)Foruser-speciedunits
Uk= Uk(User)
(3) Massowratecalculation(forinstrumentswithbuilt-intemperaturesensorand
analog input)
a) Steam
In the case of saturated steam, calculate the mass ow rate by using the built-in saturated
steam table to determine the density based on the measured temperature value.
In the case of superheated steam, calculate the mass ow rate by using the built-in steam
table to determine the density based on the measured temperature value. For the pressure,
use the xed value input in the parameters or the analog input value from an external
pressure gauge.
M = ρft×Qf