Better Sensor Protection

New Coating for Density and Viscosity Transmitters

09.04.2015 The manufacturer Micro Motion has announced an improvement to its immersion-type FVM and FDM transmitters for density and/or viscosity.

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New Coating for Density and Viscosity Transmitters

The coating thickness is less than 50 microns, requiring no changes to fork design (Picture: Schwing)

For the past 15 years the company‘s Viscomaster viscosity meters have been supplied with PFA-coated sensor forks. Although PFA has excellent properties, it is vulnerable to attack by some chemicals and to impact/mechanical damage. For these reasons the manufacturer has has selected a diamond-like carbon (DLC) coating that offers a very low coefficient of friction, excellent durability (resistance to impact/mechanical damage) as well as high resistance to chemical attack. DLC is deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD). The surfaces have a glass-like amorphous (non-crystalline) structure, free from pinhole defects. It can be used at operating temperatures of up to 450 °C, well above the operating temperature of the Viscomaster (200 °C). The coating thickness is less than 50 microns, which requires no changes to fork design and does affect Viscomaster performance. The key advantages are resistance to chemical (H2S) attack and a robust coating resistant to mechanical damage. The user benefits from a reduced field failure rate.

Facts For Decision-Makers:

  • chemical resistance
  • stable up to 450 °C
  • reduced failure

Achema 2015 Hall 11.0 – E2

 

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