Installation and Configuration Manual
P/N MMI-20015439, Rev. AA
July 2009
Micro Motion® 7829
Visconic Viscosity Meter
Short and Long Stem Versions
©2009, Micro Motion, Inc. All rights reserved. Viscomaster is a registered trademark, and Viscomaster Dynamic is a trademark of
one of the companies of Emerson Electric Co. Micro Motion is a registered trade name of Micro Motion, Inc., Boulder, Colorado.
The Micro Motion and Emerson logos are trademarks and service marks of Emerson Electric Co. All other trademarks are property
of their respective owners.
Micro Motion pursues a policy of continuous development and product improvement. The specification in this document may
therefore be changed without notice. To the best of our knowledge, the information contained in this document is accurate and
Micro Motion cannot be held responsible for any errors, omissions, or other misinformation contained herein. No part of this
document may be photocopied or reproduced without prior written consent of Micro Motion.
Contents
Chapter 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Safety guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 About the meter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 What is it? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.2 7829 meter measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2.3 What is it used for? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2.4 Principle of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 2 Installation (Short Stem) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Boundary effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Standard installations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3.2 Meter orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3.3 Free stream installation - flanged fitting . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3.4 Free stream installation - weldolet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.5 T-piece installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3.6 Flow-through chamber installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4 Installation in the pipeline or system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.5 Typical installations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.5.1 Jacketed pipeline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.5.2 Flow-through chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Chapter 3 Installation (Long Stem) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2 Installation considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2.1 Fluid at the sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2.2 Flow rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2.3 Entrained gas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2.4 Solids contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.3 Open-tank installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.4 Closed-tank installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.5 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.6 If the Tank is Pressurized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Chapter 4 Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.2 Installation considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.2.1 Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.2.2 EMC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.2.3 Ground connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.2.4 Cabling requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.2.5 Surge protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.2.6 Installation in explosive areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Installation and Configuration Manual 1
Contents
4.3 Wiring the meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4.4 Power supply input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.5 Modbus (RS-485) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.6 4-20 mA outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.7 Wiring procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.8 Further information on RS-485 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.8.1 RS-485 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.8.2 RS-485 to RS-232 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.8.3 RS-485 multi-drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
4.8.4 Transmission mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Chapter 5 Using ADView and ProLink II . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.1 Using ADView software. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.1.1 What is ADView? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.1.2 Installing ADView . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.1.3 Starting ADView. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
5.1.4 Understanding ADView features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.2 Using ProLink II software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5.2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5.2.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5.2.3 Connecting from a PC to a meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5.2.4 ProLink II configuration upload/download . . . . . . . . . . . . . . . . . . . . . . . . 54
5.2.5 ProLink II language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Chapter 6 Calibration Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.1 Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.1.1 Factory calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.1.2 Calibration of Transfer Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.1.3 Instrument calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.1.4 General viscosity equation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.1.5 General density equation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.2 Calibration certificate example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
6.3 User calibration checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
6.3.1 Ambient air calibration check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
6.3.2 On-line calibration adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Chapter 7 General Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
7.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
7.2 General maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
7.2.1 Physical checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
7.2.2 Electrical check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
7.2.3 Performance check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
7.2.4 Calibration check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
7.3 Fault analysis and remedial action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
7.3.1 Troubleshooting faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
7.3.2 Mechanical servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
7.3.3 Time period trap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Appendix A Factory Default Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
A.1 Default configuration for analog outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
2 Micro Motion 7829 Visconic Viscosity Meter
Contents
Appendix B Calculated Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
B.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
B.2 Kinematic viscosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
B.3 Base kinematic viscosity referral using ASTM D341 . . . . . . . . . . . . . . . . . . . . . . . . . 70
B.4 Base density referral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
B.4.1 Matrix density referral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
B.4.2 API density referral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
B.5 Calculated parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
B.5.1 Specific gravity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
B.5.2 Degrees Baumé . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
B.5.3 Degrees Brix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
B.5.4 Quartic equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
B.5.5 % Mass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
B.5.6 % Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
B.5.7 API degrees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Appendix C Safety Certification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
C.1 Safety certification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Appendix D Modbus Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
D.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
D.2 Accessing Modbus registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
D.2.1 Establishing Modbus communications . . . . . . . . . . . . . . . . . . . . . . . . . . 78
D.3 Modbus implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
D.3.1 Register size and content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
D.4 Modbus register assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
D.5 Index codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
D.5.1 API product type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
D.5.2 Pressure, Temperature, Density and other Units . . . . . . . . . . . . . . . . . . . 83
D.5.3 Special function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
D.5.4 Special function quartic equation name. . . . . . . . . . . . . . . . . . . . . . . . . . 84
D.5.5 Special function quartic equation units . . . . . . . . . . . . . . . . . . . . . . . . . . 84
D.5.6 Output averaging time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
D.5.7 Analog output selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
D.5.8 Referral temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
D.5.9 Software version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
D.5.10 Hardware type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
D.5.11 Unit type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
D.5.12 Status register flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
D.5.13 Line dynamic viscosity units. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
D.6 Establishing Modbus communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
D.7 Example of direct Modbus access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
D.7.1 Example 1: Reading line density (16-bit register size) . . . . . . . . . . . . . . 89
D.7.2 Example 2: Reading line density (32-bit register size) . . . . . . . . . . . . . . 90
Appendix E Product Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
E.1 Density / temperature relationship of hydrocarbon products. . . . . . . . . . . . . . . . . . . 91
E.1.1 Crude oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
E.1.2 Refined products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
E.1.3 Platinum resistance law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
E.1.4 Density of ambient air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Installation and Configuration Manual 3
Contents
E.1.5 Density of water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
E.1.6 Velocity of sound in liquids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Appendix F Return Policy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
F.1 General guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
F.2 New and unused equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
F.3 Used equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
4 Micro Motion 7829 Visconic Viscosity Meter
Chapter 1
Introduction
1.1 Safety guidelines
Handle the 7829 Visconic viscosity meter with great care.
• Do not drop the meter.
• Do not use liquids incompatible with materials of construction.
• Do not operate the meter above its rated pressure or maximum temperature.
• Do not pressure test beyond the specified test pressure.
• Ensure all explosion-proof requirements have been applied.
• Ensure the meter and associated pipework are pressure tested to 1-1/2 times the maximum
operating pressure after installation.
• Always store and transport the meter in its original packaging, including the transit cover
secured by grub screws.
• To return a meter, refer to the Return Policy appendix for more information on the Micro
Motion return policy.
Safety messages are provided throughout this manual to protect personnel and equipment. Read each
safety message carefully before proceeding to the next step.
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
Installation and Configuration Manual 1
Introduction
Electronics housing
Spigot
Tines
Stem (available in varying
lengths)
Stem is sealed at both ends
and air filled
1.2 About the meter
1.2.1 What is it?
The 7829 Visconic viscosity meter is a digital viscosity meter, based on the proven tuning fork
technology of Micro Motion. It is an all-welded sensor designed to be mounted directly into a
pipeline or in a tank. Viscosity and density are determined from the resonance of the tuning fork
immersed in the fluid, and a temperature sensor (RTD) is also fitted within the meter.
The 7829 meter is available in a variety of materials, and the immersed tines can be laminated with
PFA to inhibit the build up of residues such as asphaltenes.
The meter contains integral processing electronics to provide full ‘on node’ configuration, enabling it
to perform a variety of calculations.
Two forms of output are available:
• Two off 4-20 mA analog outputs, factory set but have individually configurable span, bias,
limits, and filter options. The standard factory settings for these outputs are Line Kinematic
Viscosity on Analog Output 1 and Line Temperature on Analog Output 2. Alternatively, the
analog outputs may be controlled by one of the following:
• Line dynamic viscosity
• Line density
• Base or referred kinematic viscosity
• Base or referred density (API or Matrix referral)
• Line temperature
• An RS-485 (Modbus) interface, giving access to other measurement results, system
information and configuration parameters.
2 Micro Motion 7829 Visconic Viscosity Meter
Introduction
No signal converter is required, which simplifies wiring and enables the 7829 meter to be connected
directly to a plant monitoring and control systems and/or a local indicator.
The 7829 meter is factory set to perform API density referral. Re-configuration of the meter’s default
settings (see Appendix A) is achieved by linking a PC to the Modbus (RS-485) connection and
running the Micro Motion ADView or ProLink II (v2.9 or later) software. Once configured, the PC
can be removed.
1.2.2 7829 meter measurements
The 7829 meter directly measures the following fluid properties:
From these properties, the 7829 meter calculates:
• Line dynamic viscosity – measured in centiPoise - cP.
• Line Density – measured in kg/m
3
, g/cc, lb/gal, or lb/ft3.
• Temperature – measured in °C or °F.
• Line and base (referred) kinematic viscosity – measured in centiStokes - cSt.
• Line and base (referred) density – API or Matrix.
• Referral is made to 15°C, 1.013 bar; or at 60°F, 14.5 psi.
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
1.2.3 What is it used for?
The 7829 meter is ideally suited to applications where continuous real time measurement of viscosity
is required. The meter is particularly suited where viscosity is an indication of the behavioral
properties of the fluid, for example in applications involving spraying, coating or dipping.
Some uses are in the oil and petrochemical industry for:
•Refining
•Marine
•Power
• Heavy fuel oil (HFO) blending and bunkering
1.2.4 Principle of operation
The 7829 meter operates on the vibrating element principle, the element in this case being a slender
tuning fork structure which is immersed in the liquid being measured.
The tuning fork is excited into oscillation by a piezo-electric crystal internally secured at the root of
one tine, whilst the frequency of oscillation is detected by a second piezo-electric crystal secured at
the root of the other tine. The sensor is maintained at its first natural resonant frequency, as modified
by the surrounding fluid, by an amplifier circuit located in the electronics housing.
The electronics circuit actually excites the sensor into oscillation alternately at two positions on the
frequency response curve as shown in Figure 1-1. In doing this, the quality factor (Q) of the resonator
may be determined as well as the resonant frequency.
For details of the viscosity and density calculations, see the Calculated Parameters appendix.
Installation and Configuration Manual 3
Introduction
0dB level
-3dB level
Frequency
τ
B
τ
A
A
B
Figure 1-1 Frequency response curve showing the quality factor (Q) calculation
Response
4 Micro Motion 7829 Visconic Viscosity Meter
Chapter 2
Installation (Short Stem)
For information on installing a long-stem version of the 7829 Visconic viscosity meter, see Chapter 3.
2.1 Introduction
All drawings and dimensions given in this manual are given here for planning purposes only. Before
commencing fabrication, reference should always be made to the current issue of the appropriate
drawings. Contact Micro Motion for details.
For further information on handling and using the meter, see “Safety guidelines” on page 1
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
There are a variety of external factors that affect the ability of the 7829 Visconic viscosity meter to
operate successfully. In order to ensure that your system works correctly, the effects of these factors
must be taken into consideration when designing your installation.
There are two main aspects to consider:
• The accuracy and repeatability of the measurements
• The relevance of the measurements to the overall purpose of the system
Factors which may adversely affect accuracy and repeatability include:
• The presence of gas or bubbles within the fluid being measured
• Non-uniformity of the fluid
• The presence of solids as contaminants
• Fouling of the meter
• Temperature gradients
• Cavitations and swirls
• Operating at temperatures below the wax point of crude oils
• The correct pipe diameter that corresponds to the calibration of the meter.
In some applications, absolute accuracy is less important than repeatability. For example, in a system
where the control parameters are initially adjusted for optimum performance, and thereafter only
checked periodically.
The term achievable accuracy can be used to describe a measure of the product quality that can be
realistically obtained from a process system. It is a function of measurement accuracy, stability and
system response. High accuracy alone is no guarantee of good product quality if the response time of
the system is measured in tens of minutes, or if the measurement bears little relevance to the operation
of the system. Similarly, systems which require constant calibration and maintenance cannot achieve
good achievable accuracy.
Installation and Configuration Manual 5
Installation (Short Stem)
long axis
short
axis
Factors which may adversely affect the relevance of the measurements could include:
• Measurement used for control purposes being made too far away from the point of control, so
that the system cannot respond properly to changes.
• Measurements made on fluid which is unrepresentative of the main flow.
2.2 Boundary effects
Any insertion device or meter can only measure the properties of the fluid within the region of fluid to
which it is sensitive.
For practical reasons, it is helpful to consider the sensitive, or effective region, for the viscometer as
an ovoid centered on the tips of the tines with its long axis aligned with the direction in which the
tines vibrate, as shown below. The 7829 meter is insensitive to the properties of the fluid outside this
region and progressively more sensitive to fluid properties the closer the fluid is to the tines. Density
can be considered a “mass centered” effect and viscosity a “surface centered” effect in this
visualization; i.e. the measurement of density is more uniformly sensitive to the density of fluid
throughout the region while viscosity measurement is much more critically sensitive to fluid on the
surface of the tines.
If part of this volume is taken up by the pipework or fittings there is said to be a boundary effect; i.e.,
the intrusion of the pipe walls will alter the calibration. The diagram below illustrates the 7829 meter
installed in a pocket on the side of a 4" (100 mm) horizontal pipe line (viewed from above). The
effective region is completely enclosed within the pipe line and thus is completely fluid.
6 Micro Motion 7829 Visconic Viscosity Meter
Installation (Short Stem)
Top or Plan view
4” horizontal pipe
2”Schedule 40
Pocket or “T”
This next view shows other pipe outlines superimposed:
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
Installation and Configuration Manual 7
The smaller circle represents a 4" (100 mm) vertical pipe, which because the 7829 meter orientation is
constant irrespective of pipe orientation intersects the effective region. The 6" (150 mm) pipe is the
smallest pipe diameter to completely enclose the effective region when the pipe is vertical. Thus
smaller pipe diameters can lead to a variety of different geometries which would each require a
separate calibration.
An alternative condition is shown in the next diagram where the side pocket is extended until it passes
completely through the effective region producing a “core”:
Installation (Short Stem)
From this, it would appear that almost every installation requires a separate in situ calibration – a very
undesirable situation. The problem is resolved by providing standard calibration geometries which
can be used in all pipe work configurations and thereby allow the factory calibration conditions to be
reproduced in the process.
2.3 Standard installations
2.3.1 Overview
To overcome the need for in situ calibration for every installation, three standard installations are
proposed. If an installation conforms to one of these standards, the factory calibration of the 7829
meter is valid, and in-situ calibration unnecessary. Table 2-1summarizes the three installations. For
tank installations, consult Micro Motion.
Table 2-1. Types of standard installations
Installation type Free stream T-piece Flow-through chamber
Description 7829 meter tines are inserted
Flow rate 0.3 to 0.5 m/s at the 7829 meter. 0.5 to 3 m/s at main pipe wall. 10 to 30 l/min.
Viscosity 0.5 to 12500 cP 0.5 to 100 cP 0.5 to 1000 cP
Temperature
(1)
directly into the main fluid flow.
-50 to 200°C
(-58 to 392°F)
7829 meter tines are contained
in a side pocket off the main
flow.
-50 to 200°C
(-58 to 392°F)
7829 meter tines are
contained in a flow-through
chamber in which fluid is
circulated from the main
flow.
-50 to 200°C
(-58 to 392°F)
8 Micro Motion 7829 Visconic Viscosity Meter
Installation (Short Stem)
Table 2-1. Types of standard installations continued
Installation type Free stream T-piece Flow-through chamber
Main flow pipe size 100 mm (4") horizontal
150 mm (6") vertical, or larger.
Advantages • Simple installation in large bore
pipes.
• Ideal for clean fluids and
non-waxing oils.
• Suitable for line viscosity
measurement and simple
referrals.
Not recommended
for
• Dirty fluids.
• Low or unstable flow rates.
• Where step changes in
viscosity can occur.
• For small bore pipes.
100 mm (4") horizontal or
larger.
• Simple installation in large
bore pipes.
• Ideal for clean fluids and
non-waxing oils.
• Suitable for line viscosity
measurement and simple
referrals.
• Dirty fluids
• Low or unstable flow rates.
• Where step changes in
viscosity can occur.
• for small bore pipes.
• Where temperature effects
are significant.
Any.
• Adaptable installation to
any diameter main pipe
and for tank applications.
• Ideal for flow and
temperature conditioning.
• Suitable for complex
referrals and for use with
heat exchangers.
• Suitable for step changes
in viscosity.
• Fast response.
• Ideal for analyser
cubicles.
• Uncontrolled flow rates.
• Careful system design
required to ensure
representative
measurement.
• Frequently requires the
use of a pump.
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
(1)
Approval for use in hazardous areas is limited to –40 to +200°C (–40 to +392°F)
2.3.2 Meter orientation
The meter must always be installed horizontally, and orientated to allow flow in the gap between the
tines. This is irrespective of the pipe line orientation, and helps to prevent the trapping of bubbles or
solids on the meter.
Installation and Configuration Manual 9
Installation (Short Stem)
Bubbles rise!
Solids sink!
the slot
must be
vertical
.
For ALL pipe and flow directions
.
the meter
must be
horizontal
Figure 2-1 Meter orientation
Note: All drawings and dimensions given in the following sections are derived from detailed
dimensional drawings. They are given here for planning purposes only. Before commencing
fabrication, reference should always be made to the current issue of the appropriate drawings contact Micro Motion for details.
2.3.3 Free stream installation - flanged fitting
Conditions:
• Flow: 0.3 to 0.5 m/s (at the meter)
• Viscosity: 0.5 to 12,500 cP
• Temperature: -50 °C to 200 °C (–58 °F to 392 °F)
[-40 °C to 200 °C (-40 °F to 392 °F) in hazardous areas]
Note: The thermal mass of the flanges may affect the response time of the meter to temperature
changes.
The view shown below is schematic to show the dimensions of the side pocket, which is fabricated by
the end user.
10 Micro Motion 7829 Visconic Viscosity Meter
Installation (Short Stem)
circlip
4” or larger;
horizontal
6” or larger;
vertical
2.75”
(70 mm ±2 mm)
7.75”
(197 mm)
Free Stream; flanged
2” (52.3 mm)
wall thickness
at least
0.15” (3.912 mm)
2” Schedule 40
4.37”
(111 mm)
0.47” (12 mm)
PTFE
ring
circlip
PTFE
ring
circlip
PFA
ring
circlip
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
The pocket geometry must be consistent with 2" schedule 40 tube in both internal diameter and
minimum wall thickness, such as:
• Internal diameter: 2" (52.5 mm)
• Wall thickness: minimum 0.15" (3.912 mm)
Weld neck or slip-on flanges may be used, according to the flange rating selected. However, for
higher rated flanges, only slip-on flanges may give the necessary clearances.
2.3.4 Free stream installation - weldolet
This is the preferred option where temperature variations are a critical factor. The reduced thermal
mass of the weldolet's taper-lock fitting renders it more able to track rapid changes in temperature.
Conditions:
• Flow: 0.3 to 0.5 m/s (at the meter)
• Viscosity: 0.5 to 12,500 cP
• Temperature: -50 °C to 200 °C (–58 °F to 392 °F)
[-40 °C to 200 °C (-40 °F to 392 °F) in hazardous areas]
The weldolet has a 1.5" taper lock fitting, and is supplied to be welded on 4", 6", 8" or 10" pipelines.
Use of the weldolet ensures that the tines of the 7829 meter are orientated correctly and are fully
inserted into the fluid stream.
Before fitting the weldolet, the pipeline must be bored through at 2.1" (52.5 mm) diameter to accept
the viscometer. The weldolet must be welded to the pipeline concentrically with the pre-bored hole.
The view shown below is a schematic to show the relevant dimensions.
Installation and Configuration Manual 11
Installation (Short Stem)
10” (254 mm)
Horizontal: 4” or larger
Vertical: 6” or larger
Weld
4.4” (111 mm)
Free stream weldolet
to suit pipe diameter
(4, 6, 8 or 10” N.B.)
2.1” (52.5 mm)
min
Figure 2-2 Free stream 1.5" Swagelock fitting
The installation will conform generally to Schedule 40 pressure ratings. The weldolet fabrication is
rated to 100 Bar at ambient temperature.
Note: Correct installation and pressure testing of the fitting is the responsibility of the user.
2.3.5 T-piece installation
Conditions:
The thermal mass of the flanges may affect the response time of the meter to temperature changes.
Flow velocity at the pipe wall and fluid viscosity must be within the limits shown to ensure that the
fluid within the pocket is refreshed in a timely manner. This installation will not respond as rapidly as
the free-stream installation to step changes in viscosity.
The view shown is a schematic to show the dimensions of the side pocket, which is fabricated by the
end user.
• Flow: 0.5 to 3.0 m/s (at the pipe wall)
• Viscosity: 0.5 to 100 cP
• Temperature: -50 °C to 200 °C (–58 °F to 392 °F)
[-40 °C to 200 °C (-40 °F to 392 °F) in hazardous areas]
12 Micro Motion 7829 Visconic Viscosity Meter
Installation (Short Stem)
“T” piece Flanged
D
4” or larger;
horizontal
or vertical
6.9”
(175 mm ±2
mm)
7.75”
(197 mm)
2” (52.3 mm)
wall thickness
at least
0.15” (3.912 mm)
2” Schedule 40
PFA
ring
circlip
0.47” (12 mm)
4.37” (111 mm)
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
The pocket geometry must be consistent with 2" schedule 40 tube in both internal diameter and
minimum wall thickness, i.e.:
• Internal diameter: 2.1" (52.5 mm)
• Wall thickness : minimum 0.15" (3.912 mm)
Weld neck or slip-on flanges may be used, according to the flange rating selected. However, for
higher rated flanges, only slip-on flanges may give the necessary clearances.
2.3.6 Flow-through chamber installation
Flow-through chambers are fabricated by Micro Motion, and are available with either weld prepared
ends or with flange or compression fittings for connection into the process pipe lines. They are
available with 1" NB, 2" NB, or 3" NB inlet and outlet pipes.
Note: The length of the inlet and outlet pipes must not be altered, otherwise the temperature response
and stability of the fitting may be adversely affected.
Conditions:
• Flow: constant, between 10 and 30 l/min for 2" sch 40 calibration bore section, 5–300 l/min
for 3" sch 80 calibration bore.
• Viscosity: 0.5 to 1000 cP
• Temperature: -50 °C to 200 °C (–58 °F to 392 °F)
[-40 °C to 200 °C (-40 °F to 392 °F) in hazardous areas]
Installation and Configuration Manual 13
• Pressure: 70 bar @ 204 °C, subject to process connections.
The PT100 is a direct insertion type, without a thermowell, and uses a ¾" Swagelok connection.
The diagram below shows an example of this type of standard installation.
Installation (Short Stem)
Dimensions shown in inches (mm)
The three compression fittings on the flow pockets (½" drain, ¾" temp probe, and 1-½" mounting nut
for the meter) are rated to above the working pressure of the flow pocket. The fittings may be
Swagelok or Parker; both are used in manufacture.
The fittings are certified to the following standards:
• Swagelok: SO9001 / 9002, ASME,TUV,CSA,DNV
• Parker: ISO 9001 / 9002, TUV, DNV, LLOYDS
2.4 Installation in the pipeline or system
Viscosity is a highly sensitive indicator of change in a fluid – a key reason why viscosity
measurement is increasingly being chosen as a process measurement.
This sensitivity means that the measurement can be very sensitive to extraneous effects and therefore
great care must be taken to consider all the factors which affect measurement when assessing the
installation requirements.
Like many other meters, the optimum performance of the viscometer depends upon certain conditions
of the fluid and configuration of the process pipe-work. By introducing appropriate flow conditioning,
the optimum performance of the 7829 meter can be achieved at any chosen location in the process
system.
14 Micro Motion 7829 Visconic Viscosity Meter
Installation (Short Stem)
You must first select a location which serves the application objective; e.g. installed close to the point
of control. Then, consideration can be given to fluid conditioning at that point. Where the application
requirements allow a degree of tolerance in the point chosen for installation, the installation may be
able to take advantage of natural flow conditioning.
The choice of mechanical installation (free stream, “T” piece or flow-through chamber) will be
dictated partly by application needs and partly by the fluid conditions, such as:
• Condition of fluid at the sensor
• Thermal effects
• Flow rate
•Entrained gas
• Solids contamination
Fluid at the sensor
The fluid in the effective zone of the 7829 meter must be of uniform composition and at uniform
temperature. It must be representative of the fluid flow as a whole.
This is achieved either by mixing of the fluid either using a static inline mixer or taking advantage of
any natural pipe condition that tends to cause mixing, such as pump discharge, partially open valves.
The viscometer should be installed downstream where the flow is just returning to laminar flow
conditions.
Thermal effects
Avoid temperature gradients in the fluid and in the pipe work and fittings immediately upstream and
downstream of the viscometer.
Always insulate the viscometer and surrounding pipework thoroughly. Insulation must be at least
1" (25 mm) of rockwool, preferably 2" (50 mm) (or equivalent insulating heat jacket) and enclosed in
a sealed protective casing to prevent moisture ingress, air circulation, and crushing of the insulation.
Special insulation jackets are available from Micro Motion for the flow-through chambers, which,
because of the low volumetric flow rates and hence low heat flow, are more vulnerable to temperature
effects.
Avoid direct heating or cooling of the viscometer and associated pipe work upstream and downstream
that is likely to create temperature gradients. If it is necessary to provide protection against cooling
due to loss of flow, electrical trace heating may be applied, provided it is thermostatically controlled
and the thermostat is set to operate below the minimum operating temperature of the system.
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
Where flow-through chambers are used and where base (or referred) viscosity is required and the
behavior of the fluid is such that the temperature of the sample flow will require controlling, heat
exchangers should be fitted upstream a sufficient distance from the chamber so that the fluid
temperature is relatively stable. Insulation should be extended from the viscometer to the outlet from
the heat exchanger. Fluid heat exchangers should be controlled by modulating the flow rate of the heat
exchange fluid and not by modulating the sample flow rate.
Flow rate
Flow rates and velocities should be maintained relatively constant within the limits given. The fluid
flow provides a steady heat flow into the viscometer section, and the flow rate influences the self
cleaning of the sensor and the dissipation of bubbles and solid contaminants.
Installation and Configuration Manual 15
Installation (Short Stem)
Where it is necessary to install the viscometer in a by-pass (either using the free stream installation in
a 4" diameter horizontal by-pass, or a flow-through chamber), flow may be maintained using pressure
drop, pitot scoop, or by a sample pump. Where a pump is used, the pump should be upstream of the
viscometer.
Entrained gas
Gas pockets can disrupt the measurement. A brief disruption in the signal caused by transient gas
pockets can be negated in the signal conditioning software, but more frequent disruptions or serious
gas entrainment must be avoided. This can be achieved by observing the following conditions:
• Keep pipe lines fully flooded at all times
• Vent any gas prior to the viscometer
• Avoid sudden pressure drops or temperature changes which may cause dissolved gases to
break out of the fluid
• Maintain a back pressure on the system sufficient to prevent gas break out (e.g. back pressure
equivalent to twice the ‘head loss’ plus twice the vapor pressure)
• Maintain flow velocity at the sensor within the specified limits.
Solids contamination
• Avoid sudden changes of velocity that may cause sedimentation.
• Install the viscometer far enough downstream from any pipework configuration which may
cause centrifuging of solids (e.g. bends).
• Maintain flow velocity at the sensor within the specified limits.
• Use filtration if necessary.
The diagram below illustrates some of the principles outlined in this section. It shows a free-stream
viscometer installation with an additional sample take off. The position of both is such that the static
mixing (which could be caused by pump discharge or partially closed valve), has negated the adverse
effects of bends and established laminar flow, and has ensured that the fluid is thoroughly mixed and
thus of uniform composition and temperature. The ideal place for a free stream or “T” piece
installation, or for the by-pass take off point is where the flow has just begun to be laminar.
Note: The insulation extends upstream and downstream far enough to prevent conduction losses in the
pipe walls from degrading the temperature conditioning of the fluid at the sensor.
16 Micro Motion 7829 Visconic Viscosity Meter
Installation (Short Stem)
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
2.5 Typical installations
The following diagrams illustrate some typical solutions for line viscosity measurement, simple base
viscosity referral and base viscosity using temperature control of the sample flow.
In all examples, the fluid flow is assumed to be uniform in composition and temperature as it enters
the viscometer section.
2.5.1 Jacketed pipeline
The diagram below shows a jacketed pipeline. The heating fluid in the jacket will cause temperature
gradients, and therefore it is discontinued through the viscometer section. If protection against cooling
due to loss of flow is required through the unjacketed section then it must be provided using electrical
trace heating.
Installation and Configuration Manual 17
Installation (Short Stem)
Figure 2-3 Jacketed pipeline installation
Alternatively, the viscometer can be installed in a by-pass. By ensuring that the sample is mixed
where the by-pass draws off the main pipeline, it is not necessary to discontinue the main pipe line
jacket. This is shown below.
Figure 2-4 4" bypass using DP to generate constant flow at the meter
18 Micro Motion 7829 Visconic Viscosity Meter
Installation (Short Stem)
PT10 0
(optional)
Pump
10-30 l/min
Insulation
(required)
Optional drain line (½”)
either vented or
returned to process
Line or Base Viscosity: temperature not conditioned
Horizontal Pipe line
Flowmeter
(optional)
1”-2” sample lines
Always install the chamber with flow
in horizontal and flow out vertically
upwards.
Drain, to purge solids, is vertically
down and can be vented and/or
returned to line.
Side Wall Tappin g
Side Wall Tapping
with Pitot Scoop
Meter in 2”
flow-through
chamber
2.5.2 Flow-through chamber
The diagram below shows the use of a flow-through chamber. This provides a compact installation
and is particularly suited to flows of contaminated fluids, since the design of the chamber encourages
self cleaning. Because the volume flow rate is low, the heat flow is low and therefore the insulation
must be as efficient as possible. The low heat flow makes this system ideal for base (or referred)
viscosity measurement using heat exchangers.
Figure 2-5 Pumped bypass
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
Installation and Configuration Manual 19
Installation (Short Stem)
20 Micro Motion 7829 Visconic Viscosity Meter
Chapter 3
Installation (Long Stem)
For information on installing a short-stem version of the 7829 Visconic viscosity meter, see
Chapter 2.
3.1 Introduction
All drawings and dimensions given in this manual are given here for planning purposes only. Before
commencing fabrication, reference should always be made to the current issue of the appropriate
drawings. Contact Micro Motion for details.
To protect the tines from damage, a Transit Cover is fitted prior to shipment from the factory. The Transit
Cover is held in place by 2 grub screws. Be sure to remove and store the Transit Cover prior to
installation. Re-fit the Transit Cover if storing or transporting, such as for repair. If the Transit Cover has
been lost, it can be purchased from Micro Motion.
For further information on handling and using the meter, see “Safety guidelines” on page 1
There are a variety of external factors that affect the ability of the 7829 Visconic viscosity meter to
operate successfully. In order to ensure that your system works correctly, the effects of these factors
must be taken into consideration when designing your installation.
There are two main aspects to consider:
• The accuracy and repeatability of the measurements
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
• The relevance of the measurements to the overall purpose of the system
Factors which may adversely affect accuracy and repeatability include:
• The presence of gas or bubbles within the fluid being measured
• Non-uniformity of the fluid
• The presence of solids as contaminants
• Fouling of the meter
• Temperature gradients
• Cavitations and swirls
• Operating at temperatures below the wax point of crude oils
In some applications, absolute accuracy is less important than repeatability. For example, in a system
where the control parameters are initially adjusted for optimum performance, and thereafter only
checked periodically.
Installation and Configuration Manual 21
Installation (Long Stem)
The term achievable accuracy can be used to describe a measure of the product quality that can be
realistically obtained from a process system. It is a function of measurement accuracy, stability and
system response. High accuracy alone is no guarantee of good product quality if the response time of
the system is measured in tens of minutes, or if the measurement bears little relevance to the operation
of the system. Similarly, systems which require constant calibration and maintenance cannot achieve
good achievable accuracy.
Factors which may adversely affect the relevance of the measurements could include:
• Measurement used for control purposes being made too far away from the point of control, so
that the system cannot respond properly to changes.
• Measurements made on fluid which is unrepresentative of the main flow.
3.2 Installation considerations
Density and viscosity is a sensitive indicator of change in a fluid - a key reason why density and
viscosity measurement is increasingly being chosen as a process measurement. However, density and
viscosity measurements can be sensitive to extraneous effects and, therefore, great care must be taken
to consider all the factors which may affect measurement when assessing the installation
requirements.
Like many other meters, the optimum performance of the viscosity meter depends upon certain
conditions of the fluid. You must first select a suitable position where the fork’s tines are always
completely immersed in the fluid. Although tolerant of solids, turbulence and bubbles, there should
be at least a 50 mm clearance from objects e.g. impellers, pipe stubs, etc.
Then consideration can be given to fluid conditioning at that point. Where the application
requirements allow a degree of tolerance in the point chosen for installation, the installation may be
able to take advantage of natural flow conditioning.
The choice of mechanical installation will be dictated partly by application needs and partly by the
fluid conditions, such as:
• Condition of fluid at the sensor.
• Flow rate.
•Entrained gas.
• Solids contamination.
3.2.1 Fluid at the sensor
The fluid in the effective zone of the long stem 7829 meter must be of uniform composition and at
uniform temperature. It must be representative of the fluid as a whole. This is achieved by taking
advantage of any natural tank condition that tends to cause mixing, such as pump discharge, partially
open valves etc.
3.2.2 Flow rate
If there is flow in the tank, the rate of flow should ideally be not more than 0.5 m
3
/s. If flow rates
exceed this, a ‘shift’ will be introduced into density and viscosity readings. The higher the flow rate
is, the larger the ‘shift’. Measurements also become ‘noisy’.
22 Micro Motion 7829 Visconic Viscosity Meter
Installation (Long Stem)
3.2.3 Entrained gas
Gas pockets can disrupt the measurement. A brief disruption in the signal caused by transient gas
pockets can be negated in the internal signal conditioning software, but more frequent disruptions or
serious gas entrainment must be avoided. This can be achieved by observing the following
conditions:
• Vent any gas prior to the viscosity meter.
• Avoid sudden pressure drops or temperature changes which may cause dissolved gases to
break out of the fluid.
3.2.4 Solids contamination
• Avoid sudden changes of velocity that may cause sedimentation.
• Install the meter far enough away from any build-up of solids.
• Maintain flow velocity at the sensor within the specified limits.
• Specify the long-stem 7829 meter with a non-stick PFA protective layer.
3.3 Open-tank installation
Installation (Short Stem) Electrical ConnectionsInstallation (Long Stem)Introduction
Only the safe area model may be used in open-tank installation.
1. For open-tank installations, the long-stemmed 7829 meter is clamped to a structure (see
Figure 3-1). The position of the clamp determines the insertion depth.
Figure 3-1 Open-tank installation
2. Keep the tines away from the tank wall (see Figure 3-2).
Installation and Configuration Manual 23
Installation (Long Stem)
Figure 3-2 Keeping tines away from the tank wall (Open-tank)
3. Keep the tines immersed in fluid (see Figure 3-3).
Figure 3-3 Keeping tines immersed (Open-tank)
4. Keep tines away from objects and disturbed flow (see Figure 3-4).
24 Micro Motion 7829 Visconic Viscosity Meter
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