Vessels drain connection

Connections to equipment are typically 50 mm and 80 mm for process vessels and exchangers, according to the size of the equipment. Each connection includes an accessible block valve. Double block valves are provided if required. A check valve should be included if overpressure or other hazard could result from reverse flow during simultaneous drainage from more than one vessel. Individual connections from the equipment are made into the top of the drain header. 

Vessel drain systems can be very dangerous and deserve careful attention. There is a tendency to connect high-pressure vessels with low-pressure vessels through the drain system. If a drain is inadvertently left open, pressure can communicate through the drain system from the high-pressure vessel to the low-pressure vessel. If this is the case, the low pressure vessel relief valve must be sized for this potential gas blowhy condition. 

These are not normally required. Where wet gas is supplied, it will be necessary to fit a vessel at low points in the installation to collect any condensate or fluid. This vessel shall be in a readily accessible position and a valve, suitably plugged or capped, shall be fitted to its drain connection. In the exceptional case where hydraulic pressure testing is to be carried out, similar provisions must be made. 

Dampening vessels should have drain connections. Some are designed with baffles to make them more efficient or to achieve the same result in a smaller volume. These should be designed to permit drainage to a common point. 

Other reactor coolant system penetrations are the pressurizer surge line in one hot leg the four direct vessel injection nozzles for the safety injection system two return nozzles to the shutdown cooling system, one in each hot leg two pressurizer spray nozzles vent and drain connections and sample and instrument connections. 

Because there are no drain connections at the bottom of the fuel storage pool, the spent fuel assemblies can never be exposed by an accidental valve opening or pipe break. Fuel is not stored in the upper containment pool during normal operation. A portable underwater vacuum system, similar to that used in swimming pools, can be used to clean pool walls, floors, and internals removed from the reactor vessel. Deposition at the water line of the pool walls is minimized by several surface skimmers. These devices remove a portion of the surface water and recycle it to the pool. 

The principle of liquid transfer in the La Marast reaction vessel is very simple. In order to drain the reaction vessel, the single outlet of the vessel is connected to an evacuated waste container via a selection valve (Fig. 1). The air (or inert gas, if required) present in the reaction vessel starts to expand and pushes solvent from the reaction vessel into the evacuated waste container. At the same time, the reaction vessel is evacuated. The selection valve is then switched and the evacuated reaction vessel is connected to a solvent reservoir. The liquid in the reservoir (which was under atmospheric pressure) flows into the reaction vessel. Thus, the only operation necessary to wash the resin beads in the reaction vessel is turning a handle of a valve. 

Closed drain headers are normally provided for safe drainage of equipment containing severely toxic, corrosive, pollutant or high cost chemicals (e.g., phenol, sulfuric acid, monoethanolamine, sulfur dioxide, catacarb) where there is an appreciable inventory in a number of processing vessels in a plant. The header should be at least 50 mm in diameter, and should be tied into the major vessels and equipment with 25 mm minimum size connections (20 mm is considered adequate for pumps). The header may be routed to a gravity drain drum (with recovery to the process by pump or gas pressurization), or to a pumpout pump returning to the process, or in the case of sulfuric acid, to an acid blowdown drum. 

Blowdown from the boiler(s) should always be taken to either a blowdown sump or blowdown vessel before discharging into drains. Both should be adequately sized to give cooling by dilution and be fitted with vent pipes to dissipate pressure safely. The boiler(s) should have independent drain lines for the main manually operated blowdown valve and the drains from a continuous blowdown system. Where more than one boiler is connected to either system the line should be fitted with a check or secondary valve capable of being locked. 

Spill containment is required around the marine vessel during loading and unloadingto prevent the spread of an accidental release. Means should be provided to manage small spills that may occur during transfer arm or hose system connection, disconnection or draining. 

A single-stage rotary vane pump ( S0 = 25m3h ) is used to remove residual water from a vacuum vessel which has been cleaned, washed with demineralised water and drained. The pump is fitted with an oil-mist filter. If the exhaust temperature is 75 °C and ambient air ( T= 20 °C, RH = 50%, p0 = 1013 mbar) is used as the ballast gas, calculate the maximum amount of water that can be handled by the pump. (Assume that the pump is directly connected to the chamber.)... 

The venous anatomy is very variable. Venous blood flows centrally via the deep cerebral veins and peripherally via the superficial cerebral veins into the dural venous sinuses, which lie between the outer and meningeal inner layer of the dura and drain into the internal jugular veins (Stam 2005) (Fig. 4.4). The cerebral veins do not have valves and are thin walled, and the blood flow is often in the same direction as in neighboring arteries. There are numerous venous connections between the cerebral veins and the dural sinuses, the venous system of the meninges, skull, scalp, and nasal sinuses, allowing infection or thrombus to propagate between these vessels. 

The DPET s electrodes are in the form of concentric cylindrical plates suspended from the top of the vessel and are connected to a high-voltage transformer such that adjacent plates are given opposite charges. As the oil passes through the electrodes, water droplets are influenced by the field to create a sinusoidal migration between plates of opposite charge. This motion serves two purposes to restrict the upward flow of the water in relation to the oil and to enhance the rate of collision of water droplets, which are distorted to form dipoles under the electric field, and thereby increase the rate of coalescence. Clean oil leaves from the top of the vessel, while water is drained out from the bottom. Instrumentation available on this unit permits pressure and temperature measurement of both the feed and vessel conditions and the treated oil and outlet water flow rates. 

---