Wire wound vessels

Division 3 provides special rules for layered and autofrettage vessels. Rules for wire wound vessels and interlocking strip wound vessels has also been included. 

Ribbon- and Wire-wound Vessels 307 Core tube... 

Fig. 15.13. Hoop-stress distribution in wire-wound vessel (Example Calculation 15.9).

Comstock (226) has presented an illustrative design demttns I rating the use of E j. 15.86 in a wire-wound vessel to op( rate at 15,000 psi with a constant tensi< ii of 40,000 psi in the wire winding under operating (Conditions. 

The EN 13445 Section 1 [8] excepts layered vessels, autofrettage vessels, and prestressed vessels (p.e. wire wound vessel). 

Yokes. The need to couple the end cover to the body of the vessel may be avoided if yokes, external to the vessel, are used to resist the load arising from the internal pressure acting on the closures. However the necessity to move the vessel out of the yoke and remove one of the closures to gain access to the inside of the vessel limits its use for chemical process equipment. Yokes may be pinned, welded, bolted, or wire wound. Both the vessel and yoke maybe wire wound (136). 

The woven wire mesh type are formed to control the open space between the wires, thereby limiting the maximum size particle that can pass through. The cartridge is installed in cases or small vessels to facilitate quick replacement, or they can be arranged for backwash by use of proper piping connections. The wire wound units have consistent spaces for uniform particle size filtering. 

Platinum Resistance Thermometer. Platinum resistance thermometers are based on the electrical resistance of Pt. This resistance for Pt wires wound on a mica support and enclosed in a glass or silica vessel can be manufactured to be either 25.5 Q at 0°C or 2.5 Q at 0°C. The electrical resistance, typically measured in a Wheatstone or Mueller bridge, increases by about 0.1 Q or 0.01 Q, respectively, per degree centigrade (0.4%/°C). Empirical equations convert Pt resistance and its small nonlinearities to temperature ... 

Whilst perhaps more of a conventional problem, some care will be needed when removing tendons from within the inner one metre thickness of vessel concrete, as they may have become activated. Removal of wire wound tendons presents further new problems to the demolition contractor. 

For a wire wound PCRV, it has been calculated that If all the prestress were removed except for the wire windings a little either side of the equator, vertical tensile stresses large enough to cause cracking would develop around the equator level. This technique therefore would have very limited application and Is not thought to be feasible for a helically prestressed vessel. 

External-Cake Tubular Filters Several filter designs are available with vertical tubes supported by a filtrate-chamber tube sheet in a vertical cylindrical vessel (Fig. 18-115). The tubes may be made of wire cloth porous ceramic, carbon, plastic, or metal or closely wound wire. The tubes may have a filter cloth on the outside. Frequently a filter-aid precoat will be applied to the tubes. The prefilt slurry is fed near the bottom of the vertical vessel. The filtrate passes from the outside to the inside of the tubes and into a filtrate chamber at the top or the bottom of the vessel. The sohds form a cake on the outside ofthe tubes with the filter area actually increasing as the cake builds up, partially compensating for the increased flow resistance of the thicker cake. The filtration cycle continues until the differential pressure reaches a specified level, or until about 25 mm (1 in) of cake thickness is obtainea... 

The heater used for the sublimation vessel was made from a length of 15-cm. Pyrex tubing. The tube was covered partially with moistened asbestos fiber strips (ca. 1 mm. thick) which remain in place when dry. The tube was only partially covered with asbestos to allow visual inspection of the sublimation vessel. A sufficient length of nichrome wire (depending on the resistance of the wire) was wound over the asbestos base, and more asbestos was added over that already in place to hold the wire loops apart. During use, the open end was well stuffed with glass wool. 

The checkers used a Hoskins tube furnace, type FD303A (Central Scientific Co.), 17 in. long. The heater for the sublimation vessel was wound in two sections with heating wire in such a way that a decreasing temperature gradient in the direction of the pyrolysis oven was maintained. The open end of the heater was closed by an asbestos end plate which could be heated independently by a small nichrome coil. 

The apparatus shown in Fig. 2 has a 500-mL reaction vessel, which is coimected to a 50-mL reservoir for liquid /BP via a stopcock and a standard-taper joint, t The coimecting tubing between the reaction vessel and the mercury in the manometer must be wrapped with commercial heating tape or wound carefully with heating wire. The temperature of this section, which should be as short and of as small bore as feasible, is controlled with a variable-voltage power supply. It is not necessaiy to control this temperature accurately, but it should be close to the bath temperature (say, within 20°C) and must be above the boiling point of acetone (56°C). 

As calorimeter vessels the three forms illustrated below were employed. Metals, on account of their high thermal conductivity, could be used without any enclosure simply in the form of a block this was of cylindrical shape, and was provided with a hole in which was inserted a core made of the same metal and wound with platinum wire. Thin waxed paper was used for insulation the very small space between the core and the block was filled up with melted paraffin wax. The upper part of the core was... 

Further protection is given to the platinum winding by tin-foil wound round the inner tube. It is absolutely necessary that air should be present inside the silver vessel to facilitate equalization of temperature consequently, after introducing the substance the lid at the bottom was carefully sealed on. If the silver vessel leaked, as it did occasionally, this was betrayed by a rapid increase in temperature of the platinum wire during the heating, and by the inordinately slow equalization of heat. 

The third form (Fig. 7) differs only in detail from the second it was preferred for the experiments with liquid hydrogen, because it could be made of much smaller dimensions. The platinum wire was wound on the outside of the cylindrical silver vessel and covered, to avoid thermal losses, with silver foil which was soldered at the edges to give a better thermal contact this form has the advantage that the platinum wire docs not have to be introduced vacuum-tight into the inside of the silver vessel. In a small size and at low temperatures this form of calorimeter proved to be excellent. The heat capacity of the silver vessel could be calculated with good accuracy, but it was also directly determined by a series of... 

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