Description
Description
The Q46C4 4E conductivity monitor is the answer for monitoring almost any water based process. Drinking water, plating bath solutions, cooling water, process wash water or virtually any other aqueous system can be monitored accurately and reliably. The unique drive/control scheme used in the 4 electrode system allows a single sensor configuration to be used in conductivity ranges from 0-200 uS to as high as 0-2,000 mS (0-2 S). For chemical mixing application, a concentration display can be selected.
While the theory of monitoring conductivity is simple, in practice it can be very frustrating. While simple 2-electrode sensors are inexpensive and can provide accurate data, continuous monitoring of even relatively clean water can foul the electrodes and degrade the measurement.
Maintaining accuracy is made more difficult when the amount of solids dissolved in the process varies over a wide concentration range.
In a traditional 2-Electrode sensor, each electrode performs two functions. The electrodes are used to carry the AC drive voltage and also measure the current flow due to the conductivity of the water. This type of sensor has a limited conductivity range and is affected by electrode coating. In addition, changes in cable resistance and capacitance can cause measurement errors.
A 4-Electrode sensor provides two sets of electrodes, one set to carry the AC drive voltage and a separate set to sense the strength of the electric field between electrodes. This allows the drive voltage to be automatically adjusted for changes in electrode condition and allows the monitor to automatically correct for the effects of electrode fouling. It also allows the sensor to measure accurately over a very wide range of conductivity and eliminates errors due to changes in cable length.
Sensors the the Q46C4 system are available in a variety of mounting configuration: convertible style with 1″ NPT threads for pipe or tank mounting, 1½” or 2″ sanitary style fittings in 316 stainless steel and insertion system for 1¼” NPT hot tap assemblies that allow the sensor to be removed from service without shutting down the process. Flor low flow bypass applications, a Noryl sensor with quick disconnect cable and acrylic flowcell are available.
Conductivity monitors can be used to measure and display the concentration of acids or bases used in various chemical process applications. The Q46C4 is available with pre-loaded tables allowing direct display of concentration for solutions of sodium chloride (NaCl), hydrochloric acid (HCl), potassium hydroxide (KOH) and sodium hydroxide (NaOH).
In addition to these standard tables, the user may enter their own table data for other chemicals or may edit the standard tables supplied. Custom tables require data on both concentration vs conductivity and temperature vs conductivity for the chemical of interest.
