PRESSURE TRANSMITTER FAILING DUE TO ABRASION: TRY A CERAMIC CELL

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Author: cbprocess

There we go again…another failed pressure transmitter due to abrasion.

VEGA Pressure 1

Have you said this or heard someone say this.  Maybe with a little profanity thrown in for color?  Let’s face it, pressure transmitters with their thin convoluted diaphragm just wasn’t designed for installation in process lines or tanks were you have a liquid with some sort of solid flowing by it.  Whether that be pulp, sand, ore, coal or rocks the diaphragms that are designed to consistently flex and return the same way when pressure is applied to them just won’t last.  What can you do to keep your transmitters from failing so often?

Couple of solutions that are available are to use remote seals or install wet-legs to protect the transmitter from the process.  However, these solutions come with other problems such damaged seals (of course) or plugging of wet legs  A third solution is to use a VEGABAR82 transmitter that was designed for abrasive applications.  VEGA designed their VEGABAR82 transmitter so it can be direct mounted to the process and withstand solids flowing by it.  It accomplishes this by using a ceramic seal versus a metal seal.

WHAT IS A CERAMIC DIAPHRAGM?

First, I want to tell you what it is not.  Its not the same ceramic that you use every morning.  What we are talking about here is a highly engineered ceramic designed to be a very tightly packed lattice structure.  Think of it as a very organized matrix of molecules.  These engineered ceramics are extremely hard and resistant to corrosion (meaning its compatible with lots of different types of fluids) and perfect for solving the problems associate with measuring pressure in processes with entrained solids.  VEGA Pressure Cell

CERAMIC CERTEC® MEASURING CELL OVERVIEW:

The Ceramic CERTEC cell was design and is manufactured by VEGA.  It has been in use in the market for more than 10 years and has the experience of over 1 million installations worldwide. 

There are a number of advantages to using this particular ceramic cell technology:

  • Longer stability…One of the reasons for drift with a metal diaphragm based pressure transmitter is the gradual failure of the diaphragm.  Every scratch, dent, or even molecule removed from the diaphragm will cause a change in the relationship between the pressure applied and what the sensor interprets.
  • Longer life…With a stronger ceramic diaphragm, damage will be less likely. 
  • Will not contaminate your process.  The CERTEC cell is a dry cell which does not use a fill fluid.  A metallic diaphragm based transmitter is filled with an oil and if the diaphragm is ruptured it will contaminate your process.
  • No impact of Hydrogen permeation.  Ceramics have a crystal lattice structure that is very compact making it very difficult for hydrogen to permeate.  Even if it does, since there is no oil used in the transmitter, the hydrogen will not absorb into it and cause a “jiffy popped” diaphragm.
  • High over pressure protection.  The space between the ceramic diaphragm and the cell is very small and the diaphragms movement will be stopped by the cell and not get damaged.

APPLICATIONS:

  • Pulp and Paper:  Pulp digesters, head box, pressure screen,liquor recovery processes, 
  • Mining:  Slurry transportation, extraction, reduction, precipitation
  • Wastewater 
  • Oilsands extraction

The VEGABAR 82 offers a reliable measurement solution for numerous applications including: mining, pulp & paper, water & wastewater. Contact your CB Process representative today to see if this unique product meets your application requirements.

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