Circulating pump

A static leaf filter is used for cleaning machine tool coolants. These are used on the suction side of a pump circulating system, with the same pump employed for withdrawal of the filtrate as for backdushing the filter elements. SoHds in this case are removed from the sump by a scraper conveyor. 

Pump circulating excessive liquid back to suction tbrougb a breakdown bushing or a diffuser gasket area. 

Thermal power plant auxiliaries such as flow control of primary air fan, ID fan and forced-draught fans, boiler feed pumps circulating water pumps and condensate pumps, coal handling plant (e.g. ball mill, wagon tippler, and stacker reclaimer)... 

In a forced-feed lubrication system, a pump circulates lubricating oil through a cooler and filter to a distribution system that directs the oil to all the bearings and crosshead shoes. Figure 11-23 is a schematic of a typical system. The details of any one system will vary greatly. Major components and considerations of a forced feed lubrication system are as follows ... 

Kreis-laufgas, n. recycle gas. -linie,/. circular line, circumference, -ordnung, /. district regulation. -prozess, m. cyclic process, cycle, -pumpe, /. circulating pump, kreisrund, a. drcular. 

More realistic sketches of the cross section of a steam generator are in Figure 1.4. Part (a) of this figure illustrates the process of natural circulation of water between an upper steam drum and a lower drum provided for the accumulation and eventual blowdown of sediment. In some installations, pumped circulation of the water is advantageous. 

Figure 13.5 shows the much simpler equipment needed for pre-mix dispensing. Top pressure is applied from a carbon dioxide cylinder to a pre-mix tank, factory filled with carbonated drink. When the dispense valve is opened the pressure delivers product from the base of the tank via die dip tube through die cooler to the valve. Product in the python feed to the valve is kept cold by the pumped circulation of chilled water from die cooler bath. 

In the secondary loop, a feed water pump circulates water through a heat exchanger where the primary and secondary loops exchange heat. The water in the secondary loop is turned to steam here and feeds a turbine, where electricity is generated. In the boiling-water reactor, there is only one loop, and as a result, the overall efficiencies are higher at the added expense... 

The simple control scheme in Figure 2.103 measures the temperature difference (ATC-1) between the solar collector temperature and the solar water tank temperature, starts the water pump when AT > 20°C, and stops it when this temperature difference drops to 10°C. The variable-speed refrigerant pump circulation is similarly controlled. Because the condenser (lake, well, or swamp) temperature is more or less constant, AT control might not be essential and measuring only the evaporator (solar water tank temperature) by a standard thermostat (TC-2) can be sufficient. In this configuration, the refrigerant pump is started whenever the solar tank temperature is above 60°C (140°F), and the pump speed is increased to its maximum, as the temperature in the solar hot water tank reaches, say, 70°C (160°F). 

The oil is loaded into the reactor, shown with both an agitator and a pumped circulation-spray loop, and heated under vacuum (110-130°C) to reduce water and peroxide contents. Next, the oil is cooled to 70-90°C and the catalyst is added as dry powder at 0.05-0.15 percent or suspended in dry oil. Randomization requires about 30 min, with an additional 15-30 min allowed for completioa After the reaction is complete, the batch is transferred to a postbleacher where the process is arrested by inactivating the catalyst by addition of water or an (phosphoric or citric) acid solution. Bleaching earth, added to absorb the inactivated catalyst and soaps removed by filtration and the oil sent to blending or deodor-ization. Losses from the formation of FFA and FAME are —10 times the catalyst weight, with... 

Crystallisation theory is covered in Volume 2, Chapter 15, and in several other texts Mullin (1992), Van Hook (1961), Nyvlt (1971) and Janie and Grootscholten (1984). Descriptions and illustrations of the many types of commercial crystalliser used can be found in these texts and in various handbooks Perry and Green (1984), Schweitzer (1988). Procedures for the scale-up and design of crystallisers are given by Mersham (1984), (1988), (1995). Bamford (1965) includes details of the ancillary equipment required vacuum pumps, circulation pumps, valves, filters, centrifuges and dryers. 

The radiator in an automobile is a cross-flow heat exchanger ( M, = 10 kW/K) that uses air (c = 1.00 kJ/kg K) to cool the engine-coolant fluid (c = 4.00 kl/kg K). The engine fan draws 30°C air through this radiator at a rate of 10 kg/s while the coolant pump circulates the engine coolant at a rate of 5 kg/s. The coolant enters this radiator at 80°C. Under these conditions, the effectiveness of the radiator is 0.4. Determine (a) the outlet temperature of the air and (i) the rale of heat transfer between the two fluids. 

Some floor-model fryers have built-in filters. These filters are made of stainless steel mesh. Usually, a layer of filter paper is used on the screen. A built-in pump circulates the oil through the screen for several minutes. The filtered oil is used to flush the residual solids in the fryer pan, and the filtered oil is put back in the fryer pan and stored until the next operation. The oil is filtered at least once every day. For some products, it is necessary to filter the fryer oil twice or three times daily because of the heavy accumulation of crumbs. 

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