Pipes, water distribution

PVC Piping (Water Distribution, Sewerage, and Irrigation) Uni-Bell Plastics Pipe Association, 2655 Villa Creek Drive, Suite 164, Dallas, TX 75234... 

After it leaves the stoves, the hot blast enters a large refractory-lined busde pipe to distribute the gas evenly around the furnace. Multiple connecting pipes (tuyere stock) direct the hot blast to the blowpipes. At the ends of the blowpipes are the tuyeres, water-cooled copper no22les set into the refractory lining of the blast furnace. 

Saline Water for Municipal Distribution. Only a very small amount of potable water is actually taken by people or animals internally, and it is quite uneconomical to desalinate all municipally piped water, although all distributed water must be clear and free of harmful bacteria. Most of the water piped to cities and industry is used for Htfle more than to carry off small amounts of waste materials or waste heat. In many locations, seawater can be used for most of this service. If chlorination is requited, it can be accompHshed by direct electrolysis of the dissolved salt (21). Arrayed against the obvious advantage of economy, there are several disadvantages use of seawater requites different detergents sewage treatment plants must be modified the usual metal pipes, pumps, condensers, coolers, meters, and other equipment corrode more readily chlorination could cause environmental poUution and dual water systems must be built and maintained. 

An important appHcation is for filament-wound glass-reinforced pipe used in oil fields, chemical plants, water distribution, and as electrical conduits. Low viscosity Hquid systems having good mechanical properties (elongation at break) when cured are preferred. These are usually cured with Hquid anhydride or aromatic-amine hardeners. Similar systems are used for filament-win ding pressure botdes and rocket motor casings. 

For liquids flowing in pipes the pressure drop is commonly taken proportional to a power of the flow rate, usually around 2. One of the simplest correlations used in water distribution network calculation is the Hazen-Williams formula,3... 

Sample problem A is a small gravity-fed water distribution network taken from Carnahan and Wilkes (C2). The network is shown schematically in Fig. 21 with an arbitrary assignment of flow directions. The numerical data on this network including the initial guesses and the final solution are given in Tables IX and X. In addition, the following data are used in the computation p = 62.4 lbm/ft3, p = 1 cP, e = 0.01 in. for all pipes. 

The sizing of piping is based upon a hydraulic analysis for the water distribution network for the WCCE. The main delivery pipe should be sized to provide 150% of the design flow rate. A residual pressure and flow requirement at the most remote hydrocarbon process or storage location from the supply source dictates the sizing for the remaining system. Normal reliability requirements usually suggest that minimum of two sources of supply be available that are in themselves remote from each other. Therefore two remote flow calculations must be performed to determine the minimum pipe distribution size. NFPA 24 requires that the minimum residual pressure available in a fire main not be less than 6.9 bars (100 psi.). Velocity calculations should be performed which verify flows are not more than the limits of the material that is employed. 

Fire Water Distribution Piping Flushing Hydrostatic test 24... 

Fire Water Distribution Piping Flush new lines based on rates in Table 9-3. 24... 

Fire Water Distribution Piping The test should be made at no less than 200 psi (1,379 kPa) for 2 hours or 50 psi (345 kPa) above static pressure, where static pressure is in excess of 150 psi (1,034 kPa) for 2 hours. 24... 

The water distribution system in the city of Dayton, OH, uses Southdown concrete water mains to deliver water to its citizens. Routine sampling and testing of Dayton s water supply by the city s Department of Water consistently shows that the levels of metals are well below the Ohio EOA Community Drinking Water Standards, and that these levels have remained constant throughout a nine-year testing period from 1982 to 1990. Because metal leaching has not occurred, there is no reason for concern over the safety of Southdown concrete pipes to transport drinking water. 

Distribution Systems. A substantial amount of contamination of drinking water can occur while the water is in transit to the consumer after treatment. Pipes are made of copper, galvanized iron, asbestos-cement, lead, or plastic, and often polymeric or coal tar coatings are used. All of these are capable of contributing contaminants to the water, especially if the water is corrosive. Lead, copper, cadmium, and polynuclear aromatic hydrocarbons in finished water are primarily problems of water distribution and not source water contamination. Physical deterioration of the distribution system can also permit biological contamination to occur during transit. 

Some simplification is permissible for water distribution systems in metallic pipes. Then the Hazen-Williams formula is adequate, namely... 

Corrosion within the tower itself is due mainly to the particular conditions existing therein (air, humidity and temperature) and also to the chemical treatment of the water. All construction materials exposed to these conditions must be selected carefully. Hardware and piping for distribution headers have been successfully made with hot-dipped galvanized steel, cadmium-coated steel, stainless steel and silicon bronze. 

In some cooling tower designs, the main hot water distribution pipe running the length of the tower and supplying other smaller (lateral) pipes. 

Fig. 10. Illustration of the surface peak, probably formed during quenching, in the depth distribution of total deuterium introduced by heating silicon samples in the downstream gases from a plasma discharge (Johnson, 1987). Upper curve results of SIMS measurements on a sample doped with 2 x 10ls Sb atoms per cm3, deuterated 2 hr at 400°C. Lower curve same for an identical sample deuterated 2 hrs. at 500°C. Quenching was with piped water.

To determine the drinking water quality or to verify effluent discharge compliance with permit requirements, we sample the water from a tap or a sampling port in a water delivery system. Analytical data for potable water and effluent discharge samples may be compared to concentration action levels, such as the drinking water MCLs or NPDES permit limitations. Yet again we should be concerned with the issue of sample representativeness, as a water sample collected from a tap must accurately represent the water in the pipes and in the other elements of a water distribution system. 

Figure 9 gives an insight into the potential objects of studies by model (58)-(65). It shows a scheme of the main double-pipe water heat network of the heat supply system for a large urban district. The optimal synthesis problem for this network consists in the determination of flow distribution... 

The applications and uses of copper and its alloys is very extensive such as water piping and fittings, open structures (exposed to atmosphere) such as architecture and sculpture, in fresh water and seawater cooled heat exchangers, condensers in chemical, industrial and power-generating equipment buried in earth for water distribution... 

Visual inspection and the results of metal ion content in water samples, shows internal pipe corrosion in various locations in the hot water distribution system that compromises the quality of hot water. The cause of the internal pipe corrosion can be attributed to the following factors or a combination of the factors. 

Only one case reported an increase of Al during drinking water distribution (also discussed in this paper), because Al leached from the cement lining of a water distribution pipe [17, 18]. 

Cement linings of drinking water distribution pipes should be reevaluated for their possible toxicological properties. 

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