WATER TREATMENT FOR COOLING TOWERS AND BOILERS
Water treatment of cooling towers, boilers and industrial systems requires the combination of a number of physical and chemical processes, such as water bleed & replacement, chemical treatment, filtration and pumping. Because the equipment is made by different manufacturers and controlled individually, installation and operation is complicated and inefficient.
CHEMTROL® CT Series controllers incorporate all the monitoring, control and communication functions of water treatment into a single integrated command center designed around a powerful microprocessor. The Main Screen display enables the operator to manage all the process functions at a glance and to quickly respond to any changing condition. CHEMTROL® CT Series controllers operate like a computer with full-screen displays and direct access to all menus and submenus. The front panel keypad is used to move up and down each menu and enter or exit the submenus. All operating functions (such as sensor calibration, control setpoints, and alarm levels) can be easily modified from the numerical keypad.
The CHEMTROL® CT110 and CHEMTROL® CT100 Cooling Tower Controllers offer control of conductivity (or TDS) and up to three (3) chemical feed programs (for scale/corrosion inhibitors, biocides, etc). monitors conductivity and temperature of the water with electronic sensors.
For more complex systems, the CHEMTROL® CT3000C model offers make-up and bleed watermeter totalizers to feed chemicals proportionally to make-up.
SATURATION & WATER BALANCE
Proper control of saturation and water balance is required to maintain water quality and to avoid the development of scaling or corrosive conditions.
The CONDUCTIVITY sensor monitors the concentration of dissolved solids by measuring the conductivity of the water, displayed either in conductivity units (microsiemens/cm) or in parts per million of Total Dissolved Solids (TDS). Based on the information provided by the sensor, the controller automatically controls the BLEED VALVE to maintain the cooling water total dissolved solids within a user-defined range.
To avoid the development of corrosion, scale, or microbiological organisms and to limit the amount of suspended solids, ADDITIVES – such as inhibitors, biocides, dispersants, etc. – are frequently added to the cooling water system.
Development of scaling or corrosive conditions are detected by automatic calculation and display of the water LANGELIER SATURATION INDEX, based on available sensors inputs and manual data entry for Alkalinity and Calcium Hardness.
CHEMICAL AUTOMATION
More recently, cooling tower operators have become aware of the dangers caused by the presence of germs and bacteria in the water, which can cause the fatal Legionaires’ disease. These can be prevented by the injection of oxidizing sanitizers or biocides controlled by ORP, available on The CHEMTROL® CT3000 controller (option ORPCT). Indeed, numerous studies by health departments all over the world have shown that the Oxidation-Reduction Potential (ORP or Redox) generated by an oxidizing sanitizer, such as chlorine or bromine, is the most reliable indicator of both sanitizer activity and sterilisation of germs and bacteria – far superior to conventional test kit measurements.
Both CHEMTROL® CT2000 and CT3000 controllers also offer pH monitoring and control (option pHCT) to automatically add the proper amounts of acid and/or base.
FLOW/PRESSURE MONITORING AND CONTROL
The CHEMTROL® CT3000 and CHEMTROL® CT6000<</A> controllers have the capability to integrate the flow rates and cummulative volumes of up to two water lines (typically make-up and bleed) by connecting reed-switch or hall-effect water flowmeters, as well as control a solenoid valve on the make-up line to automatically add water to the system using an optical level sensor. Monitoring of the influent/effluent pressures at the heat exchanger is also available to monitor scale build-up.
FILTER BACKWASH CONTROL
When filtration of the cooling water is required to maintain clean and clear water, The CHEMTROL® CT6000 Integrated Controller includes manual or programmable operation of the backwashing cycle using data input from the influent and effluent pressure transducers. Automatic backwashing can be applied to one or more filters with programmable sequencing, adjustable backwash and advance time for each filter.