Understanding Transmitter Seals Webinar

Copyright © Yokogawa Corporation of America

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What Do I Need to Know?

Understanding Transmitter Seals

Tonya Miller & Liz Majestic

November 17, 2016


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Host: Kristina NeahrMarketing [email protected]

Presenter 1: Tonya MillerTechnical Support [email protected]

Presenter 2: Liz MajesticApplication [email protected]

Host & Presenters


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Participant audio is muted. If your computer audio is not working, please

join us using the teleconference number. Call-in toll-free number (US/Canada): 1-877-

668-4490 Call-in toll number (US/Canada): 1-408-792-

6300 Access code: 352 191 032

Event Logistics


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Questions will be taken through the Q&A window. Click on ‘Chat’ in the upper right corner of your screen.

Please send your questions to host. Questions will be answered at the end of the presentation or via e-mail shortly after.

Event Logistics


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Shortly after the event, you will receive an email containing a link to the recording, slide download, and access to all resources.

As you exit the webinar, you will have the option to participate in a short survey. Your feedback is very important to us, so please take a minute to complete.

Event Logistics


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1. What is a diaphragm seal system?2. How a diaphragm seal system works3. Direct mount vs. capillary mount4. When to use a diaphragm seal system5. Performance considerations6. Advantages & limitations


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What is a Diaphragm Seal System?


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Consists of a transmitter, a process connection, and a capillary connecting the two.

Transmitter: Measures and converts the measured variable to a signal to be transmitted.

Capillary: Connects the seal to the transmitter and contains the fill fluid.

Process Connection: The part that is in contact with the process. and is available in a host of sizes, types, flange ratings, and wetted materials.

What is a Diaphragm Seal System?


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How a Diaphragm Seal System Works


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Instrument (such as a pressure transmitter) mounted- directly or by means of a capillary or cooling element.

A diaphragm within the seal system separates the transmitter from the process medium. Any part of the diaphragm seal (i.e. diaphragm, lower housing, gaskets) which will be exposed to the process medium is selected from materials resistant to pressure, temperature and possible chemical attack by the process medium.

The diaphragm seal is also filled with a transmitting or system fill fluid. Pressure applied by the process medium to the seal diaphragm is hydraulically transmitted to the pressure element of the transmitter, generating a pressure reading.


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Principle of HydraulicsMechanically transfers the force applied at the process

diaphragm to the transmitter diaphragm. Fill fluid is a non-compressible liquid compatible with the

process temperature and pressure. Basically- the process pressure is transmitted to the

transmitter via the fill fluid.


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Accuracy & Response Time

System Accuracy & Response Time ≠

Transmitter Accuracy & Response Time

Remember:System Accuracy = Transmitter Accuracy + Capillary/Diaphragm Seal Accuracy

System Response Time = Transmitter Response + Capillary/Diaphragm Response


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Direct vs. Capillary Mount


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Direct MountSeal is attached as an integral (close

coupled) part of the transmitter body

Capillary MountRemote mounted diaphragm seal process

connection with a capillary between the seal & transmitter

Direct vs Capillary Mount


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Connection system to mount various types of seals directly to a transmitter.

Eliminates capillaries, improving the overall temperature effect.

Reasons to use a Direct Mount System:Level measurementsFlexibility in applicationsWhen close connection to tank is requiredSanitary applications where capillaries are not

recommended

Direct Mount


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A remote diaphragm seal system offers a cost effective means of preventing the process medium from coming in contact with a transmitter.

Reasons to use a Remote Mount System:High temperaturesCorrosive serviceSafetyPrevent clogging of cell body or impulse linesSanitary requirementsReplacement of wet legsAvoid contamination

Capillary (Remote) Mount


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When to Use a Diaphragm Seal System


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A transmitter alone is not always the solution Typical conditions:

Process temperatures beyond the limits of the transmitterSpecial process connections (sanitary connections, PMC

connections, quick disconnect)Presence of solids or viscous fluids Process is corrosive Hydrogen PermeationReplacement of inefficient wet legs

When to Use a Diaphragm Seal System


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Performance Considerations


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Maximum process and ambient temperature changes How quickly will the measured variable change? Location of transmitter Expected highest temperature & lowest pressure Is the process under vacuum? Measurement span Maximum pressure limits on the system Is the process connection cleaned? Type of cleaning

solution?

Performance Considerations


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Diaphragm Seal System Limitations


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LimitationsSmall span measurementsIncreased response timeDecreased total system accuracyTemperature-induced errors

Tonya Tip: always use the smallest diameter diaphragm required

*Recommended sizes for different measurement spans

Limitations


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Resources


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Questions?


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Thank you!

Understanding Transmitter Seals Webinar

Technology

Transcript of Understanding Transmitter Seals Webinar