Electrical jacket

If there is a risk of blockage, this risk should be eliminated and that applies to a spring-operated valve as well as for a pilot-operated valve. Some manufacturers have acted on this and can propose many different accessories and configurations to achieve this which have been proven to work. Pilot valves can be protected against dirt with a variety of options, and most spring valve suppliers can supply such items as steam or electrical jackets, to avoid, for instance, polymerization or formation of hydrates. 

The isocyanate solution (50 ml, 1.0N, DMF) was transferred into the thermostated three-necked flask and stirred magnetically under dry nitrogen. Then 50 ml of a catalyst in DMF was placed into the dropping funnel which was heated by means of an electric jacket. When the constant temperature was reached in both the flask and the funnel, the catalyst solution was poured into the flask and the whole mixture was thoroughly mixed. At various time intervals samples were taken and analyzed by the dibutylamine method (12). 

Recommended for products electrical connectors, electrical insulation, electrical jacketing ... 

Fig. II, 17, 2 illustrates a fractional distillation unit f for use with glass helices. The column is provided with an electrically-heated jacket the resistance shown in the Figure may be replaced by a variable transformer. The still head is of the total-condensation variable take-off type aU the vapour at the top of the column is condensed, a portion of the condensate is returned to the column by means of the special stopcock (permitting of...

The efficiency of all the above columns (and also those described below) is increased by lagging with asbestos cloth. The best results are obtained by surrounding each column with two glass jackets and heating the inner jacket electrically to a temperature within 5-10° of the fraction... 

The Stedman-type column is shown in Fig. 11, 56, 25. The characteristic features are (i) the use of a fine stainless steel wire cloth formed into conical discs, and (ii) an accurately fitting Pyrex glass jacket, produced by shrinking Pyrex glass on mandrels to the required inside dimensions. Modifications incorporating a silvered vacuum jacket and an electrically-heated jacket are marketed. This column is said to possess high efficiency but is expensive. It is generally employed in conjunction with a total-condensation variable take-off still head. 

The best results are obtained with a fractionating column surrounded by an electrically-heated jacket (compare Figs. II, 17. 2. and II. 17, 3), but this is not essential for n-caproic anhydride. For the preparation of propionic or n-biityric anhydride, a highly efficient fiactionating column must be used in order to obtain satisfactory results. 

Phosphazene polymers are inherently good electrical insulators unless side-group stmctures allow ionic conduction in the presence of salts. This insulating property forms the basis for appHcations as wire and cable jackets and coatings. Polyphosphazenes also exhibit excellent visible and uv radiation transparency when chromophoric substituents are absent. 

Maintenance of isothermal conditions requires special care. Temperature differences should be minimised and heat-transfer coefficients and surface areas maximized. Electric heaters, steam jackets, or molten salt baths are often used for such purposes. Separate heating or cooling circuits and controls are used with inlet and oudet lines to minimize end effects. Pressure or thermal transients can result in longer Hved transients in the individual catalyst pellets, because concentration and temperature gradients within catalyst pores adjust slowly. 

The Ferranti-Shidey viscometer was the first commercial general-purpose cone—plate viscometer many of the instmments stiU remain in use in the 1990s. Viscosities of 20 to 3 x 10 mPa-s can be measured over a shear rate range of 1.8-18, 000 and at up to 200°C with special ceramic cones. Its features include accurate temperature measurement and good temperature control (thermocouples are embedded in the water-jacketed plate), electrical sensing of cone—plate contact, and a means of adjusting and locking the position of the cone and the plate in such a way that these two just touch. Many of the instmments have been interfaced with computers or microprocessors. 

Metafile arsenic can be obtained by the direct smelting of the minerals arsenopyrite or loeUingite. The arsenic vapor is sublimed when these minerals are heated to about 650—700°C in the absence of air. The metal can also be prepared commercially by the reduction of arsenic trioxide with charcoal. The oxide and charcoal are mixed and placed into a horizontal steel retort jacketed with fire-brick which is then gas-fired. The reduced arsenic vapor is collected in a water-cooled condenser (5). In a process used by Bofiden Aktiebolag (6), the steel retort, heated to 700—800°C in an electric furnace, is equipped with a demountable air-cooled condenser. The off-gases are cleaned in a sembber system. The yield of metallic arsenic from the reduction of arsenic trioxide with carbon and carbon monoxide has been studied (7) and a process has been patented describing the gaseous reduction of arsenic trioxide to metal (8). 

The fact that the polymer contains no halogens along with certain unique compounding techniques for flame resistance prompts the selection of ethylene—acryflc as jacketing material on certain transportation/mifltary electrical cables and in floor tiles. 

For offshore locations where ignitible gas-air concentrations are neither continuously present nor present for long periods, API RP 14F also allows type MC cable with a continuous aluminum sheath and an outer impervious jacket (such as PVC) and armored cables satisfying ANSI/ Institute of Electrical and Electronic Engineers (IEEE) Standard No. 45. API RP 14F does not recommend IMC for offshore installations and cautions users that installations of MI cable require special precautions. The insulation of MI cable is hygroscopic (able to absorb moisture from the atmosphere). 

Electric water heaters typically use two 4,500 watt heating elements. One element is located in the lower part of the tank and provides the bulk of the energy. The other element is located near the top of the tank and is used to quickly heat a small amount of hot water after a large draw empties the tank of hot water. The elements are each controlled by separate thermostats and are interlocked so only one can come on at a time. The thermostats on electric water heaters are snap type devices that are installed directly on the outside of the tank, but inside the jacket. They are located a few inches above the element which they control. 

The common heater block shown in Fig. 19.23 can itself be subject to corrosion leading to different heat transfer conditions for different tubes, and in some later versions of the apparatus individual short heating jackets are used for each tube, which are heated with oil from either a steam-heated or electrically heated heat exchanger. This modification not only avoids corrosion problems but also obviates the necessity to machine a length of the outside of each tube to fit the semi-circular notches in the single heater block. The oil flow is adjusted to give an oil temperature of 95°C at each outlet. 

The solution of the sample to be analysed (1-100 pL) is introduced by inserting the tip of a micropipette through a port in the outer (water) jacket, and into the gas inlet orifice in the centre of the graphite tube. The graphite cylinder is then heated by the passage of an electric current to a temperature... 

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