Remote control technology controlled water quality at the 2000 Olympic Games in Sydney, Australia. Each of the three Olympic sized swimming pools, the leisure pool and spa - totaling more than ten million litres - is maintained by a Strantrol System5 unit, an electronic water chemistry control device with High Resolution Redox technology.
The device, only about 10" x 7" by 4.4", uses heavy-duty, highly refined, and very stable platinum-tipped sensors to continuously measure the actual oxidative rate of the chlorine, which is influenced by the water temperature, pH, and the number of swimmers in the pool. The rate of disinfection is directly related to the millivolt redox potential in the water; therefore, a low millivolt reading indicates that more oxidant needs to be added.
A separate probe measures pH, and initiates the feed on CO2 gas to automatically correct the pH. The Strantrol System5 controller keeps the water's pH at around 7.6, and as an extra safe-guard, once a week the pools can be automatically 'superchlorinated', if necessary, and then quickly dechlorinated with sodium thiosulfate. For economy, the System5 controller also lowers chemical levels at night when the pools are not in use.
Along with its software package, this technology provides many other sophisticated management capabilities to keep the water clean for the swimmers' health and comfort, and to extend the life of the equipment. Swimming pool quality can be remotely monitored and controlled in two ways: by viewing a computer screen, or by calling into a fax/modem with a telephone from any location.
The screen displays pH, HRR mV, Free Chlorine PPM, Total Alkalinity, Calcium Hardness, Langelier Saturation Index, and the Ryznar Stability Index, all of which can be balanced automatically with commands to feeders, or at the advice of the controllers' calculations to enhance overall water quality, maximize swimmers' comfort, and extend equipment life. The monitor also flashes a red light and outputs an audible alarm, disabling the offending equipment if necessary, alerting technicians if the C02 supply runs out, a chlorine feeder fails, a filter recirculation pump shuts down, and so forth.
All these corrections can be made remotely by computer and modem or by using the keypad on a telephone. When the technician dials into a voice modem, a recorded human voice is the prompt to a menu, where key #1 provides the water's current pH. If the pH setpoint is, for example 7.6, the technician can change it to "7.5" by pressing the keys on the telephone. The water temperature setpoint, which is kept between 82°-85°F, can also be monitored and adjusted by telephone. Normally, the Strantrol System5 unit is self-regulating, like a thermostat; however, it still allows the technician to make various changes and to program in new settings.
Once the System5 controller is connected to a computer the operator sees a colour 'graphical user interface' which shows all the current levels, alarm ranges, and control setpoints. With a click of the mouse, the software allows these to be altered. It is also simple to access the controller's datalogging memory to download graphs of the pool readings and events, such as feed cycles, alarms, auto self-probe washes, and even operator adjustments to the unit.
If USF Aquatic technicians access the controller by computer, they can remotely check the controller's diagnostics, perform operational corrections, or give advice to the operator, if necessary. With the modem feature, the controller can even contact operators or technicians, itself, for assistance.
Reliable and accurate monitoring and control of chemicals in modern aquatic facilities is maintaining ideal water balance to ensure bathers' comfort and fast swimming time for Olympic level competition. Also, improved automatic chemical control greater reduces chemical consumption and operating expenses.
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