GE Sensing C-PT Installation Guide

Measurement & Control Solutions Flow

C-PT Ultrasonic Flow Transducer

Installation Guide

916-074 Rev. B

July 2010

C-PT Ultrasonic Flow Transducer

Installation Guide

916-074 Rev. B July 2010

GESensingInspection.com

Technical content subject to change without notice.

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Contents

1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

2. Transducer Construction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

3. Measurement Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3.1 Transit-Time Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3.2 TransFlection Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

4. Couplants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

5. Installing C-PT Transducers for the Transit-time Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

5.1 Determining the Number of Traverses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

5.2 Installing the Universal Clamping Fixture - UCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

5.2a Verifying Fixture Length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

5.2b Identifying the UCF Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5.2c The Double-Traverse Method -UCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

5.2d The Single-Traverse Method - UCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

5.2e Mounting Transducers into the UCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

5.3 Installing the General Clamping Fixture - GCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

5.3a The Double-Traverse Method - GCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

5.3b The Single-Traverse Method - GCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

5.3c Mounting Transducers into the GCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

5.4 Installing the Magnetic Clamping Fixture - MCF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

5.4a Identifying the MCF Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

5.4b The Double-Traverse Method - MCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

5.4c The Single-Traverse Method - MCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

5.4d Mounting Transducers into the MCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

6. Installing C-PT Transducers for the TransFlection Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

6.1 Mounting the TransFlection Mode Clamping Fixture - TMCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

6.1a Mounting the TMCF in a <180o Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

6.1b Mounting the TMCF in a 180o Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44

6.2 Mounting the Transducers into the TransFlection Mode Clamping Fixture - TMCF. . . . . . . . . . . . . . . . . . . . . .47

7. Maintaining the C-PT Transducers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50

8. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

8.1 General Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

8.2 Hazardous Area Certifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

C-PT Ultrasonic Flow Transducer Installation Guide iii

Contents

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iv C-PT Ultrasonic Flow Transducer Installation Guide

Preface

Information Paragraphs

Note paragraphs provide information that provides a deeper understanding of the situation, but is not essential to

•

the proper completion of the instructions.

• Important paragraphs provide information that emphasizes instructions that are essential to proper setup of the

equipment. Failure to follow these instructions carefully may cause unreliable performance.

• Caution! paragraphs provide information that alerts the operator to a hazardous situation that can cause damage to

property or equipment.

• Warning! paragraphs provide information that alerts the operator to a hazardous situation that can cause injury to

personnel. Cautionary information is also included, when applicable.

Safety Issues

WARNING! It is the responsibility of the user to make sure all local, county, state and national codes,

regulations, rules and laws related to safety and safe operating conditions are met for each installation.

Auxiliary Equipment

Local Safety Standards

The user must make sure that he operates all auxiliary equipment in accordance with local codes, standards, regulations, or laws applicable to safety.

Working Area

WARNING! Auxiliary equipment may have both manual and automatic modes of operation. As equipment

can move suddenly and without warning, do not enter the work cell of this equipment during automatic operation, and do not enter the work envelope of this equipment during manual operation. If you do, serious injury can result.

WARNING! Make sure that power to the auxiliary equipment is turned OFF and locked out before you

perform maintenance procedures on the equipment.

Qualification of Personnel

Make sure that all personnel have manufacturer-approved training applicable to the auxiliary equipment.

Personal Safety Equipment

Make sure that operators and maintenance personnel have all safety equipment applicable to the auxiliary equipment. Examples include safety glasses, protective headgear, safety shoes, etc.

Unauthorized Operation

Make sure that unauthorized personnel cannot gain access to the operation of the equipment.

C-PT Ultrasonic Flow Transducer Installation Guide v

Preface

Environmental Compliance

Waste Electrical and Electronic Equipment (WEEE) Directive

GE Measurement & Control Solutions is an active participant in Europe’s Waste Electrical and Electronic Equipment (WEEE) take-back initiative, directive 2002/96/EC.

The equipment that you bought has required the extraction and use of natural resources for its production. It may contain hazardous substances that could impact health and the environment.

In order to avoid the dissemination of those substances in our environment and to diminish the pressure on the natural resources, we encourage you to use the appropriate take-back systems. Those systems will reuse or recycle most of the materials of your end life equipment in a sound way.

The crossed-out wheeled bin symbol invites you to use those systems.

If you need more information on the collection, reuse and recycling systems, please contact your local or regional waste administration.

Visit http://www.gesensing.com/environment/weee.htm this initiative.

for take-back instructions and more information about

vi C-PT Ultrasonic Flow Transducer Installation Guide

1. Introduction

The C-PT ultrasonic flow transducer is used exclusively with the GE line of ultrasonic flowmeters. These transducers measure the flow rate of sonically-conductive liquids through pipes having diameters between 2 in. (5 cm) and over 300 in. (760 cm). Such measurements are typically independent of the pipe material.

This document provides the following instructions on installing and maintaining C-PT transducers:

• Transducer Construction - below

• Measurement Methods - page 2

• Couplants - page 3

• Installing Transducers for the Transit-Time Method - page 4

• Installing Transducers for the TransFlection Method - page 40

• Maintaining Transducers - page 50

• Specifications - page 51

2. Transducer Construction

Each C-PT transducer assembly consists of the following components (see Figure 1 on page 2):

• a metallic cover with 1/2” NPT male thread for attaching a junction box

• a transducer that consists of a peizo electric element mounted on a wedge and wired to the BNC connector

• a BNC style connector for use in connecting the transducer to the flowmeter.

The internal cavity of the assembly, including the transducer cover and the transducer head, is filled with a damping compound. The C-PT is available in the following process temperature ranges:

• Normal: -4 to 122

• Medium: -4 to 293

• High: -4 to 363

*This temperature is for ATEX certified designs. Consult factory for higher temperatures.

IMPORTANT: Transducer assembly C-PT-H must be mounted in such a way that it is protected against impact.

F (-20 to 50oC)

F (-20 to 145oC)

F (-20 to 184oC)*

C-PT Ultrasonic Flow Transducer Installation Guide 1

BNC Connector

Transducer

Head

Cover

2. Transducer Construction (cont.)

Figure 1: General C-PT Transducer Assembly

3. Measurement Methods

C-PT transducers can be installed using a number of configurations and clamping fixtures; however, how this is done largely depends on the flowmeter’s measurement mode. Although many of GE flowmeters have one mode called Transit-time, some GE flowmeters have an additional measurement mode called TransFlection. Although both methods use time measurement, the method in which time is measured is different.

3.1 Transit-Time Method

When in Transit-time mode, the flowmeter transmits ultrasonic pulses through a moving liquid. The pulses that travel in the same direction as the fluid flow (downstream), travel slightly faster than the pulses that travel against the flow (upstream). The flowmeter uses various digital signal-processing techniques, including cross-correlation, to determine transit times, and then uses these times to calculate flow velocity.

3.2 TransFlection Method

To measure flow, one transducer transmits a group of pulses (typically 16 pulses) at regular intervals (approximately 5,000 to 10,000 transmissions/sec). The ultrasonic pulses travel through the liquid, reflect off scatterers (i.e. bubbles, particulates) and the signal is then received by the second transducer.

In essence, these ultrasonic signals are “pictures” taken continuously at the same location in the pipe. The flowmeter compares these pictures to one another as each picture is received. By comparing (averaging) these pictures, the flowmeter is able to eliminate stationary objects by subtracting signals that do not appear to move in all or most of the pictures. The flowmeter measures the time difference between the remaining “moving” objects on each successive picture. The time difference is called T

and is used to calculate flow.

2 C-PT Ultrasonic Flow Transducer Installation Guide

4. Couplants

GE supplies an ultrasonic couplant for your C-PT installation. The purpose of the couplant is to provide reliable transmission of ultrasound between two adjacent solid surfaces. Generally speaking, couplants perform this task by excluding air from between the adjacent surfaces. Accordingly, the C-PT transducers should be pressed tightly against the pipe, using hand pressure on the set screw to squeeze the couplant to as thin a film as practical for the given pipe surface.

The most commonly used couplants in ultrasonic testing are ordinarily satisfactory for any short-term clamp-on flowmeter application. These couplants include, in general order of preference: gels, grease, propylene glycol, oil, glycerine, and water. Long-term couplants include grease, epoxy adhesive, and solid rubber-like sheet couplant.

GE provides couplants for both permanent and temporary use as well as for high- and low-temperature applications. For long-term installations, make sure the couplant does not dry or run out.

Standard couplants supplied from GE are listed in Table 1.

Table 1: Couplants

Part No. Type Temp. Range Use

CPL-1 Standard –40 to 149°F (–40 to 65°C) Semi-Permanent CPL-2 High/Low Temperature –256 to 500°F (–160 to 260°C) Semi-Permanent CPL-3 Portable –4 to 140°F (–20 to 60°C) Temporary CPL-4 Special As Required * Difficult Applications CPL-7 Epoxy 14 to 122°F (–10 to 50°C) Permanent CPL-8 Solid Sheet –40 to 446°F (–40 to 130°C) Permanent

* Installations involving hotter or colder temperatures than listed above, may require special couplants. Consult GE for these applications.

C-PT Ultrasonic Flow Transducer Installation Guide 3

5. Installing C-PT Transducers for the Transit-time Method

Installing the C-PT transducers consists of determining the number of traverses, mounting the clamping fixture to the pipe and then mounting the transducers into the clamping fixture.

Use the sections that follow to properly install the fixture and transducers.

CAUTION! A flowmeter’s accuracy and performance depends on the location, spacing, and alignment of

the transducers. The transducer spacing is unique to your installation.

5.1 Determining the Number of Traverses

The first step of installation is determining the number of traverses. The transducers can be mounted using one of two methods (see Figure 2 on page 5):

• Double-traverse method (“V” method) - transducers are mounted on the same side of the pipe and the ultrasonic

signal is bounced from one transducer to the other, off the opposite pipe wall.

• Single-traverse method (“Z” method) - transducers are mounted diagonally across from each other. The ultrasonic

signal is transmitted directly from one transducer to the other, across the pipe.

For pipe diameters from 4 to 20 in., always try the double-traverse method because it is easier to configure and yields greater accuracy . However , if the pipe has poor inside surface conditions or the fluid is highly attenuating, you may not be able to obtain a reliable signal. Therefore, you should use the single-traverse method. Typically, you should try the single-traverse method for pipe diameters greater than 20 in. Spacing of the transducers is calculated by the electronics after all the installation parameters have been programmed into the flowmeter.

• Universal clamping fixture - page 6

• General clamping fixture (permanent installation) - page 19

• Magnetic clamping fixture - page 30

4 C-PT Ultrasonic Flow Transducer Installation Guide

5.1 Determining the Number of Traverses (cont.)

Double Traverse (“V” Method)

Single Traverse (“Z” Method)

Ultrasonic Signal Path

Transducer

Transducers

TOP VIEW

Figure 2: Double- and Single-Traverse Installations

C-PT Ultrasonic Flow Transducer Installation Guide 5

5.2 Installing the Universal Clamping Fixture - UCF

The Universal Clamping Fixture (UCF) acts as a spacing device and a transducer holder. The UCF is available in two lengths and consists of a number of components. Before you begin installation, you should verify your fixture is the correct length and familiarize yourself with the fixture components.

5.2a Verifying Fixture Length

Make sure you note the following restrictions for your clamping fixture. The UCF is available in two lengths, 12 in. and 24 in. (~30.5 cm and ~61 cm). Each size fixture can be installed for a single- or double-traverse method. However, depending on the method used, there are pipe size restrictions that are outlined in Ta ble 2.

Table 2: UCF Pipe Sizes

Clamping Fixture

Length

12-in. (30.5 cm) 2 to 24 in. (5 to 61 cm) 2 to 12 in. (5 to 30.5 cm)

24-in. (61 cm) 24 to 48 in. (61 to 122 cm) 12 to 24 in. (30.5 to 61 cm)

Note: The mounting chain provided is best suited for your application.

Single-Traverse

Pipe Diameter

Double-Traverse

Pipe Diameter

5.2b Identifying the UCF Components

The UCF has two adjustable short blocks that are used for the double-traverse method. Two slide tracks connect the blocks. A ruler attached to one of the tracks helps set the transducer spacing. For single-traverse methods, a long block is also used.

The blocks are used to hold the transducers in position for accurate measurement. The UCF is chained or strapped around the pipe. The blocks are positioned using the spacing dimension calcul ated by the flowmeter. Then the transducers are mounted into the blocks. Figure 3 on page 7 shows the short and long blocks.

The transducer installation consists of mounting the UCF to the pipe and then mounting the transducers into the fixture. Refer to the appropriate section that follows for instructions:

• Double-traverse Method - page 8

• Single-traverse Method - page 11

6 C-PT Ultrasonic Flow Transducer Installation Guide

5.2b Identifying the UCF Components (cont.)

End View

Side View

Counter Nut

Short Block

1 Screw Hook

Long Block

2 Screw Hooks

Thumbscrew

Chain

Example with Short Blocks

Slide Track

(fixed and adjustable)

Pressure Bolt

Figure 3: Components of the UCF

C-PT Ultrasonic Flow Transducer Installation Guide 7

S = Spacing

Select one method to set the spacing

Centerline

5.2c The Double-Traverse Method -UCF

Note: The instructions in this section can also be used for a multiple-traverse method. However, you must use an

EVEN number of traverses. The distance the signal travels from one side of the pipe wall to the opposite side of the pipe wall is considered one traverse. For more than two traverses

There are three advantages to using the double-traverse method:

, consult the GE factory.

• Accuracy is improved because the signal is in the fluid longer than with a single-traverse.

• This configuration can reduce some effect of an underdeveloped flow profile.

• If there is enough pipe length available, the double-traverse fixture is easier to install.

The procedure for mounting the UCF involves setting the transducer spacing and fastening the fixture on the pipe. Please note you will only need the short block assembly for a double-traverse installation; the long block is not used.

1. Obtain the transducer spacing dimension S, as described in the programming section of the Startup Guide.

2. Be sure the location you have chosen for the installation has at least 10 pipe diameters of straight, undisturbed flow

upstream and 5 pipe diameters downstream of the measurement point.

3. Prepare the pipe where you intend to pla ce the clamping fixture by making sure it is clean and free of loose

material. Sanding, though usually not required, may be necessary to take off any high spots. When sanding, be careful to preserve the original curvature of the pipe.

4. Using the attached ruler, move the blocks so they are a distance S from each other . Use the pressure bolt or the ends

of the blocks as reference points. .

8 C-PT Ultrasonic Flow Transducer Installation Guide

5.2c The Double-Traverse Method -UCF (cont.)

Side View

Top View

5. Position the clamping fixture along the horizontal plane of the pipe, but not on the top or bottom. Make sure the

chains on both blocks are on the same side of the fixture and are op posite the ruler.

6. Wrap the chain around the pipe and fasten the chain on the J screw hook on the opposite side of the block. Do this

for both blocks.

7. Using the screw hook on the blocks, tighten the chains until the fixture is secured snugly to the side of the pipe.

Note: Make sure the chains are perpendicular to the clamping fixture and are not twisted. If the chains are slanted,

the slack may cause the fixture to move around. The slack may also change the transducer spacing after the transducers are mounted.

C-PT Ultrasonic Flow Transducer Installation Guide 9

Side View

Top View

5.2c The Double-Traverse Method -UCF (cont.)

Figure 4 shows a completed double-traverse installation without transducers. Proceed to Mounting Transducers into the UCF

on page 16.

Figure 4: A Double-Traverse Clamping Fixture Installation (w/o transducers)

10 C-PT Ultrasonic Flow Transducer Installation Guide

5.2d The Single-Traverse Method - UCF

Line

Top of Pipe

Side View

Note: The instructions in this section can also be used for a multiple-traverse method. However, you must use an

ODD number of traverses. The distance the signal travels from one side of the pipe wall to the opposite side of the pipe wall is considered one traverse.

The procedure for mounting the UCF for the single-traverse method requires a long block and two short blocks. The long block is fastened to the pipe first and then the short block assembly is properly aligned and fastened at 180° from the long block.

You will need a marker or scribe to locate and mark the transducer locations on the pipe. Do the following:

1. Obtain the transducer spacing dimension S, as described in the programming section of the Startup Guide.

2. Be sure the location you have chosen for the installation has at least 10 pipe diameters of straight, undisturbed flow

upstream and 5 pipe diameters downstream of the measurement point.

3. Prepare the pipe where you intend to place the UCF by making sure it is clean and free of loose material. Sanding,

though usually not required, may be necessary to take off any high spots. However, be careful to preserve the original curvature of the pipe and not to eradicate the marks on the pipe.

4. Find the top of the pipe and use a level to draw a line parallel to the pipe’s axis.

C-PT Ultrasonic Flow Transducer Installation Guide 11

Spacing

Mark

Side View

Spacing

Crossmark

Side View

Spacing

Crossmark

Side View

5.2d The Single-Traverse Method -UCF (cont.)

5. Make two marks on the line equal to the transducer spacing distance S, as calculated by the meter.

6. From one of the marks, measure around the circumference of the pipe a distance equal to one quarter the pipe’s

circumference and make a crossmark with the marker or scribe.

7. From the other mark, go in the other direction around the pipe for on e quarter the circumference and make another

crossmark.

12 C-PT Ultrasonic Flow Transducer Installation Guide

5.2d The Single-Traverse Method -UCF (cont.)

Fasten Chains

Top View

Fasten Chains

Top View

Tighten Screw Hooks

Tighten

Screw Hooks

Top View

8. Center the long block over one of the crosssmarks on the pipe. Align the long block so that the pressure bolt is over

the center of the crossmark. Fasten the block by wrapping both chains around the pipe and fastening the chains to the screw hooks on the opposite side of the block.

9. Use the wing nuts to tighten the chains on the long block until it is secured snugly to the pipe.

Note: Make sure both chains are perpendicular to the bottom of the block and are not twisted. If the chains are

slanted, the slack will cause the block to slide.

C-PT Ultrasonic Flow Transducer Installation Guide 13

Top View

Short Block

Crossmark

(One of two)

Crossmark

Short Block

(one of two)

Top View

5.2d The Single-Traverse Method -UCF (cont.)

10. Position the clamping fixture rails so that one of the short blocks is placed over the remaining crossmark on the

opposite side of the pipe and the pressure bolt is over the center of the crossmark. Make sure the block does not lie on top of the chains of the long block.

11. Wrap the chain around the pipe and fasten the chain to the screw hook on the opposite side of the block. Do this for

both short blocks.

Note: Make sure the chains on both blocks are on the same side of the fixture and are opposite the ruler.

12. Tighten the pressure bolt all the way down on the short block that is NOT positioned over the crossmark. This will

act as a reminder to not install the transducer in that block.

14 C-PT Ultrasonic Flow Transducer Installation Guide

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