Self draining

Undrainable traps that accumulate liquids and absorbent solid wastes should be avoided. Structures should be designed to be self-draining. 

A gas seal shall be furnished if required to reduee purge gas requirements. The gas seal shall be self draining. The gas seal must be qualified by test data showing oxygen eoneentration below the seal at proposed purge rate and at least 50 mph simulated wind eondition. 

Wliere possible, all flame arresters should be installed so that the elements will be self-draining. If liquid can accumulate in the housing, provision should be made to drain any accumulated liquid that could block the flow of gases through the flame arrester. 

A non-ferrous dust cap with chain should be provided to close the end of the filling pipe and protect the thread when not in use. When the filling pipe is not self-draining into the tank a gate valve should be fitted as close as possible to the hose coupling. Where there is any possibility of damage or misuse of the terminal equipment a lockable fill cap should be fitted and, if considered necessary, the terminal enclosed in a lockable protective compartment. 

All filling lines should be self-draining. Where this is not possible with residual fuel installations, trace heating and lagging should be applied, and this is particularly important in exposed positions. This will ensure that any oil fuel remaining in the filling pipe will be at pumping viscosity when delivery is made. 

Where, of necessity, the vent pipe rises to a considerable height, excessive internal pressure on the tank may result, due to the pressure head of oil should an overflow occur. To prevent any possible tank failure due to such an occurrence a vent pipe pressure-relief device must be provided. It should be self-draining to reduce the risk of blockage, particularly when using heavy oil fuel. Codes require that these devices should not place any restriction on oil flow and must discharge within the bund area. 

Bonnet design Sloped bonnet (30° minimum) for self-draining of catalyst. 

Pipeworks are designed to be self-draining with a slope of at least 1% over their length to prevent accumulation of water. 

Self-draining hydrants and monitors should be used on underground mains installed in freezing climates. Protection against mechanical damage should also be provided where necessary, usually by means of guard posts. 

The nozzle shall be a self-draining, nonclogging-type nonferrous material. All internal piping or header for multicells, if employed, shall be galvanized steel or cast iron. 

All starch systems have to be designed to prevent settling of starch granules, which have a density of about 1.5 g/cm3. Piping has to be sized to maintain a velocity of at least 45cm/s and must be equipped for self-draining, particularly in vertical sections.91 In case of a power loss exceeding 30 minutes all slurry pipes should be flushed and drained. An air lance will be required for resuspension of settled starch. 

Self-draining voive Chain operated voive Reel voive Quench voive Needle or V-port valve Angle nonreturn valve... 

A— Self-draining volve Chain operated valve Reel valve... 

If a wet method for collection is selected, such as a wet electrostatic precipitator, fiber-type self-draining mist eliminator, or wet scrubber, ammonia can be regenerated from the salt solution by reaction with a readily available metal oxide such as lime or zinc oxide with formation of a stable sulfur product for disposal. These metal oxides, however, as well as their reaction products, are insoluble and could cause deposition on heat transfer surfaces and/or clogging in the regenerating equipment. Therefore, as indicated in Figure 2, to ensure continuity and reliability of the process, a soluble metal oxide was utilized (in the form of sodium hydroxide solution) to regenerate the ammonia in the experimental work described. This procedure also allows more eflFective utilization of the metal oxide the soluble oxide (NaOH) can be regenerated in batch equipment outside the continuous portion of the process by reaction with either the aforestated insoluble reactants, lime, or zinc oxide. Better control is aflForded in a batch reactor with more eflBcient use of reactants. However, in full-scale equipment undersirable deposition of reactant and product may be controllable so that batch operation may not be necessary. 

This improves temperature control of the material In the lines and avoids settling of reinforcing materials when they are used. All lines should be designed to be self-draining to simplify machine clean out. Smooth inside surfaced flexible hoses lined with Teflon are preferred where flexible lines are required. Where these lines are jacketed, It is preferred that the jackets be coupled to the suction side of the recirculating oil pumps to keep the oil pressures low. Should leakage occur between the jacket and the reactant streams, then It is more likely that the reactants will leak into the oil than visa versa. Oil contamination will adversely affect nylon RIM reaction speed and physical properties. Many manufacturers of RIM equipment recommend that all tanks, valves and fittings for nylon RIM machines be made of stainless steel. Mild steel and... 

It should also be self-draining into a vacuum-receiver, which collects the solvent as well as maintains the vacuum integrity of the entire system. The condensate receiver should have a sight glass so that visual inspection will indicate when it needs emptying. Obviously the receiver should be large enough to contain all of the condensate from one batch of product. 

Concrete should not be poured directly on a vapor barrier as this would prevent drainage of excess bleed water from the concrete during curing, and tearing of the barrier. The vapor barrier should usually be covered with a minimum of 3 inches (75 mm) of compacted, self-draining granular fill upon which the concrete is poured. 

Relief line headers, individual relief lines, blowdown lines and flare lines should be self-draining from all relief valve outlets to the knock-out drum, flare stack or a point at the plant limit. A pocketed relief line system is more expensive, because usually an extra condensate pot is required with instruments, valves and pumps. To eliminate... 

As a minium requirement, lime tips should, therefore, be built on sites which do not have any significant natural springs and the surface layer should be contoured so that it is self-draining. 

Small quantities of liquid should always be expected in column vapor outlets. The origin of this liquid can either be entrainment from the column (fine droplets can pass even through mist eliminators and coalesce in the overhead line), or atmospheric condensation. Low points in vapor outlet lines should be avoided as these tend to trap and accumulate liquid. The accumulated liquid back-pressures the column, causing instability, erratic operation, and slug flow into the downstream unit one case history where this occurred has been reported (203). Vapor outlet lines should be sloped (i.e., self-draining) ei-... 

Vapor bypass piping and equalizing lines shoiild be self-draining and should contain no low points where condensate can accumulate. 

Piping layouts should be simple and designed for liquid velocity not exceeding 0.6 m/s. The number of valves should be kept to a minimum. The lines shonld be self-draining. 

HALO eye/facewash features the self-draining Aquaduct ", which reduces the risk of contaminated stagnant, standing water, With more coverage and a superior wash pattern, HALO users experience ---... 

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