| 摘要 |
<p>The circuit is of the type in which the concn. of impurities increases progressively during circulation of the water, e.g. in the cooling water circuit of an atmospheric condenser in a refrigeration system. A programmable controller is linked to an incremental flow-meter on the water make-up supply, an additive metering pump, an additive tank agitator and a circuit discharge to drain valve. The controller prevents pump operation when the discharge valve is open. Pref. the additive metering pump delivers in direct proportion to the increments signalled by the flowmeter. Pref. the opening of the discharge valve is triggered volumetrically. Pref. the agitator does not operate while the pump is working. Since the discharge valve is closed while additives are pumped in, the amt. of freshly injected additives lost to drain is greatly reduced. Since the agitator does not operate during pumping, concentrated pockets of additive are not directed into the pump. The level of additives is accurately maintained so that rusting and scale formation in the circuit are avoided.</p> |
