ESD Systems - Questions And Answers

We flow extremely pure silica "sand" through quartz tubing in a manufacturing process. The sand comes out of a vibratory feeder into a glass funnel and then passes through about 4 feet of quartz tubing. We occasionally have problems with the sand clogging in the tubing. Is there any way to dissipate the static charge? Note - for purity reasons, we can't change the tubing from quartz to metal. - Anonymous

This process is experiencing is charge build-up in the tube via tribocharging when the sand makes contact with the quartz tubing. There are two ways to quickly remove charge from a charged insulator. One way is to use a controlled neutralizing ionization source which sounds impractical in this case. The other is to use radiation which will neutralize the charges, but needs to be done in a controlled safe environment. Some other possibilities: Involves a design change to incorporate rotating the quartz tube with new tubes, like a revolving barrel in a hand gun. After each successful transfer, to rotate tubes, where all tubes not being used are sprayed with ionized compressed clean air.; Increase the diameter of the tubing; Heat or cool the tubing, depending if the tubing is charging negatively or positively respectively.; Vibrate the tubing (may increase tribocharging, but may also (with gravitational forces) break some of the atomic bonding from tribocharging); Rotate the tubing along the center axis (may increase tribocharging, but may also (with gravitational forces) break some of the atomic bonding from tribocharging).

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