When should the filling hole on a refillable electrode be open or plugged?

Document ID

Document ID TE7241

Version

Version 1.0

Status

Status Published

Published Date

Published Date 08/11/2017
Question
When should the filling hole on a refillable electrode be open or plugged?
Summary
When and when not to plug the fill hole on a refillable electrode.
Answer
When a probe is used for measurement or calibration, the electrolyte will flow through the junction and into the sample or standard. During measurement or calibration the filling hole should be open. If closed it will cause a head pressure to be built up preventing the flow of this electrolyte. (Just like covering the opening of a straw with a finger and removing the straw from the water. The water stays in the straw until you remove your finger and equalize the pressure inside the straw.)

Most probes have some film covering this fill hole when they are first received, removing this is required for the probes to fully function.

In between use the filling hole should be plugged to restrict this flow as well as help prevent evaporation of the the internal electrolyte.
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