There are only two ways that I can see RF getting transmitted by fluid:
1. The fluid is conductive, and is flowing in plastic pipe. In this case, the fluid behaves as a wire, and can conduct RF just fine. The solution to this problem would be to run the fluid through a section of metal pipe/tubing that is well grounded at RF, also making sure that the fluid stays in good electrical contact with the inside of the pipe/tubing (i.e., no oxide build-up on the inside surface). 2. The piping/tubing is metal and is acting as a circular waveguide. The fluid would need to be a good dielectric for this to happen. The waveguide could transmit a signal, but only for wavelength<1.3*diameter. Note that the effective diameter is increased by the square root of the dielectric constant of the fluid. The problem with this scenario is how the RF is getting into and out of the system. This could happen at any non-conductive or poorly conducting joints, such as sections of plastic pipe or flange joints with a non-conductive gasket and bolts making poor electrical connection. Don Borowski Schweitzer Engineering Labs Pullman, WA STEVEN BRODY <[email protected]>@majordomo.ieee.org on 12/27/2002 07:32:53 AM Please respond to STEVEN BRODY <[email protected]> Sent by: [email protected] To: [email protected] cc: Subject: RF in Fluids We have a chiller installed in a customer application where RF is used in their process, but we believe RF is being transmitted to our product via the fluid. Soe anh one have any suggestions on how to measure RF in fluids - type of equipment, etc.? Thanks in advance and best wishes o the EMC/PSTC Family for a happy and healthy holiday season, Steve Brody ([email protected]) ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
