| 摘要 |
<p>In a recirculatory water system of the kind in which water is lost as water vapour, the invention provides a unit having ducting (1) through which part only of the water flows. The unit includes various components disposed in the following order along the ducting: a monitor such as a conductivity probe (9), blow-down means, consisting of an electrically-operated valve (14) and a flow regulator (15), a non-return valve (18) and dosing means (19, 20 and 21). When the monitor detects a concentration of dissolved solids greater than a predetermined concentration it causes blow-down, during which the valve is opened for a predetermined period. Thereafter, blow-down is inhibited for a further period. After a predetermined number of blow-downs, the dosing means adds such materials as biocides and chemicals to reduce corrosion and/or scale-formation, so as to replace those lost during blow-down.</p> |
