Cooling water return line

Figure 5.8 Heavily pitted surface of a mild steel cooling water return line. Note the deep localized metal loss surrounded by aureoles of rust. Pitting is common when oxygen concentration varies greatly over time.

Specimen Location Cooling water return line from a reheat furnace... 

Pluggage of cooling water return lines had occurred repeatedly. The material removed from internal surfaces contained large amounts of grease, oil, and rust (Fig. 5.18). 

The impeller shown in Fig. 17.9 was removed from a cooling water return line associated with a large press. Failure of these impellers was a chronic problem, requiring impeller replacement every 3 or 4 months. 

A leak in another heat exchanger allowed flammable gas to enter a cooling-water return line. The gas was ignited by welding, which was being carried out on the cooling tower. The atmosphere had been tested before work started, five hours earlier (see Section 1.3.2). 

Always install a flow assembly from the discharge side of the recirculating pump to either a (lower pressure) cooling water return line, or the tower sump. The flow rate through the flow assembly should be 3 to 4 gpm. 

A gas test meter shows combustibles are emanating from the cooling water return-line discharge distributor. 

A shaking cooling water return line, which moves because of expanding vapor in the lines. 

For sterilization the jacket is heated by steam. Valves 4-6, 8, and 10 are closed and the pump 7 is off. Valve 11 is opened to drain the jacket. After a short period, valve 11 is closed and valve 12 is opened. Valve 1 is opened to let steam into the jacket. The condensate drains through the steam trap 13. The temperature and pressure of the circuit are monitored at TICl and PIl. Cooling is carried out by closing valves 12 and 1 valves 8 and 4 are opened. Cooling water enters the circuit at valve 4, Aows up the jacket and out to the cooling water return line (Fig. 21). All operations are generally automated for consistent and error-free condol. 

The distribution system of an ICES is the same as that of a conventional district heating system. Each ICES has warm water supply and cool water return mains. Systems that supply both heating and cooling at the same time may have independent distribution systems for hot and cold water. Distributed systems using groundwater as a heat source may have only a distribution water supply line. Cascaded and distributed ICESs have separate heating distribution systems for each building. 

Cooling water lines are generally below grade and should run right under the aligned channel nozzles of all coolers. The cooling water return header is usually adjacent to the cooling water line. 

N Drain system Primarily water analyzed for temperature, pH, total suspended solids, oil and grease per NPDES permit. NPDES Discharge Point Number 006 via a 42-in raw water return line. Periodic release of low-level radionuclides from emergency core cooling system pumps. 

Disengaging standpipes or chambers should be installed on the water return line to the cooling tower to release gases before the water reaches the tower water distribution system. 

Bleed water can be taken from the sump (but not from any point where dirt or sludge can block the valve) or from the return line after the heat exchangers. Where bleed is taken from the return line, this should be at a point before the injection of chemical inhibitor. For large cooling systems, it may prove useful to employ a small manual bleed valve to continuously discharge perhaps 70 to 80% of the required flow and to provide the balance via a conductivity controlled, solenoid valve. 

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