Drain piping

Drain piping usually connects to an upstream pressure vessel and, even if the 

Two flow regimes are possible for drain piping self-venting and siphon flow. Liquid in a self-venting line occupies a portion of the pipe cross-section, and gas moves freely with, or counter to, the liquid. Siphon flow refers to a liquid or two-phase downflow where pressure increases in the direction of flow. 

Lines will be self-venting if the following correlation is used to determine drain nozzle sizes  

horizontal pipe will also become self-venting at this transition. However, the transition is very sensitive to pipe slope and somewhat sensitive to length. Open-channel-hydraulics technology must be used for analysis of horizontal pipe. 

When the line pressure drop in gas or vapor flow exceeds roughly 40 percent of the absolute upstream pressure, density variations must be considered. The NASA charts can be used to solve compressible flow problems. Adiabatic, subsonic, compressible flow for two common cases are given  

---

Fluidized combustion of coal entails the burning of coal particles in a hot fluidized bed of noncombustible particles, usually a mixture of ash and limestone. Once the coal is fed into the bed it is rapidly dispersed throughout the bed as it bums. The bed temperature is controUed by means of heat exchanger tubes. Elutriation is responsible for the removal of the smallest soHd particles and the larger soHd particles are removed through bed drain pipes. To increase combustion efficiency the particles elutriated from the bed are coUected in a cyclone and are either re-injected into the main bed or burned in a separate bed operated at lower fluidizing velocity and higher temperature. 

Vl = liquid velocity in the drain pipe Pl = liquid density Pg = g3.s density D = pipe inside diameter h = liquid height... 

For additional information, see Simpson (Chem. Eng., 75(6), 192-214 [1968]). A critical Fronde number of 0.31 to ensure vented flow is widely cited. Recent results (Thorpe, 3d Jnt. Conf. Multi-phase Flow, The Hague, Netherlands, 18-20 May 1987, paper K2, and 4th Int. Conf. Multi-phase Flow, Nice, France, 19-21 June 1989, paper K4) show hysteresis, with different critical Fronde numbers for flooding and untlooding of drain pipes, and the influence of end effects. Wallis, Crowley, and Hagi (Trans. ASME J. Fluids Eng., 405 13 [June 1977]) examine the conditions for horizontal discharge pipes to run full. 

Copper is a galvanic metal and causes corrosion, in the presence of moisture, in nearby metals, such as cable sheathes, steel structure and water, gas or drain pipes, buried in its vicinity. With all such metafs. it forms a complete electrolytic circuit and corrodes them. Tinning may give protection against its galvanic effects but this is ati expensive proposition... 

Slides Tungsten filaments, turbine blades, lead drain pipes and organ pipes, glaciers creep-testing rigs micrographs of creep cavities. 

Cost iron Fe -r 1.8 to 4 C Low-stress uses cylinder blocks, drain pipes. 

The in-tlo v pipe should not eause interferenee with the drain pipe (Figure 17-2). 

Drain pipe design must respect proper submergence (Figure 17-3). The. submergence laws appear later in this chapter. 

Leaky PORV on the pressurizer caused ambiguous readings of the drain piping,... 

On open drain piping leaving buildings, a liquid seal should be installed as further protection to assure that gases flashing from liquids from other locations in the drain system will not exit the system in the building. 

The handle of the bucket was covered with plastic. When acetone was drained into the bucket, a static charge accumulated on the acetone and on the bucket. The plastic prevented the charge from flowing to earth via the drain pipe, which was grounded. Finally a spark passed between the bucket and the drain valve, and the acetone caught fire. 

AbleitungS kanal, m. drain, -mittel, n. revulsive derivative, -rinne,/. drain pipe, -rohr, n., -rohre, /. delivery tube, delivery pipe drain conduit. 

A water-proof machine is a totally enclosed machine so constructed that it will exclude water applied in the form of a stream of water from a hose, except that leakage may occur around the shaft provided it is prevented from entering the oil reservoir and provision is made for automatically draining the machine. The means for automatic draining may be a check valve or a tapped hole at the lowest part of the frame which will serve for application of a drain pipe. 

Applying anti-climb paint or spiked collars to access routes such as drain pipes ... 

Below gutters, soil pipes or drain pipes. 300 mm 75 mm... 

Receivers are commonly made of steel tuhe with welded dished ends, and are located horizontally. Small receivers may he vertical, for convenience of location. The liquid drain pipe from the condenser to the receiver should he amply sized, and any horizontal runs sloped to promote easy drainage. Shut-off valves in this line should not he in a horizontal outlet from the condenser, since their slight frictional resistance will cause liquid hack-up in the condenser. Oudet pipes from the receiver may he from the bottom or, by means of an internal standpipe, may leave at the top. A valve is invariably fitted at this point. 

In each of these cases, arrangements must be made to remove cold refrigerant from the coil while defrosting is in progress. Drip trays and drain pipes may require supplementary heating. 

Condensed water will run down the evaporator fins to a collection tray below the coil. From there, drain pipes will take this water to a drain. If plastic pipe is used, it should be black to exclude daylight, or slime will grow inside the tube. Drain pipes passing through rooms below freezing point need to be fitted with trace heaters. 

The quantity of these materials is relatively small compared with the amount of waste high-density poly(ethylene) produced each year. Containers made from HDPE are widely used for detergents, oil, and antifreeze, and enormous amounts of material are used in disposable applications aimually. In principle recycled poly(ethylene) could be used for drain pipes, flower pots, dustbins, and plastic crates. The problem remains, however, that economics do not favour recycling of these polymers and in the absence of Government intervention little or nothing can be done to alter commercial attitudes towards recycling. 

Flush-mounted cup sinks are commonly used to receive small to moderate amoimts of water. These are often made of polyethylene. They can be made from 3-inch PVC pipe cemented in flush with the countertop. A reducing adapter will bring the diameter down to the standard drain pipe size. 

Materials and methods. Each species studied was grown in the greenhouse in a growth unit constructed from 10 cm PVC drain pipe and T-fittings, as described previously. The growth units were filled with an artificial soil mix of perlite/coarse sand/coarse vermlculite 3/2/1 by volume. On the second and fifth day of each week four liters of a full strength Peter s Hydro-sol solution plus calcium nitrate (36.7 g/37.8 liters plus 17.0 g Ca(N03 )2 /37.8 liters) were added to each growth... 

System component Beds of highly permeable gravel and sand underlain by drain pipes.29... 

During regeneration of an adsorber in the cold box of an air separation plant, regeneration gas exited via the adsorber drain pipe. This still contained some liquid oxygen. Very low regeneration-gas flows permitted desorption of acetylene and other hydrocarbons at above normal (ppm) concentrations, these condensed or crystallised into the liquid oxygen and the mixture finally detonated, causing... 

Drains run slower and slower as greases, soaps, fats, and detergents build up on the inner walls of drain pipes and eventually cause blockage. What is the chemical action of unclogging drains with household products such as Drano and Liquid-Plumr ... 

Po ly (c h lo roethene) Rainwear, plastic handbags, floor-tiles, guttering, electric cable, sails, window frames, drain pipes... 

A tank with a drain pipe is shown in Figure 4-18. The tank contains crude oil, and there is concern that the drain pipe might shear off below the tank, allowing the tank contents to leak out. 

The clean-up fixture is part of the drip pan. The clean-up fixture and the drip pan are drained by gravity to the WP operating tank. The fixture is connected by a hose to a drain pipe that connects to the HP operating tank. The fixture is operated in the horizontal plane by a cushioned-stroke pneumatic cylinder for smooth operation. The fixture travel is two-position travel. The first travel or shorter distance is for drip pan function during normal operation and the greater or over travel is for clean-up operations. The clean-up fixture opening is such that the filling nozzle seats on the clean-up fixture as it would on a munition. 

The height of the pump shaft centerline above the baseplate shall be minimized. Adequate clearance shall be provided between the casing drain connection and the baseplate so that drain piping the same size as the connection can be installed without the use of a street (male-female) elbow. 

When specified, the suction can shall be supplied with a drain piped to the surface. 

A461 Drain pipe to surface D P SURF C 1 1 ryes (true) Or no (folse)... 

Pumps connected to variable speed drivers should be equipped with an approved relief valve. The discharge of the relief valve should be directed back to the source where possible or to drains. Piping of a relief valve back to pump suction piping should be avoided. Whenever the relief valve does not discharge to the atmosphere, a sightglass flow indicator should be installed. Constant speed pumps also require relief valves when the shut-in pump discharge pressure exceeds the rated pressure for the system components. 

---