Coil heaters

Shipment, Stora.ge, ndPrice. Tank cars and tank trailers, selected to prevent color formation, are of aluminum or stainless steel, or lined with epoxy or phenoHc resins dmms are lined with phenoHc resins. Flexible stainless steel hose is used for transfer. Because of butanediol s high freezing point (about 20°C) tank car coil heaters are provided. The U.S. Hst price for bulk quantities in 1991 was about 2.18/kg, but heavy discounting was prevalent for large contracts. 

Vei tical cylindrical helical coil heaters are hybrid designs that are classified as vertical heaters, but their in-tube characteristics are like those of horizontal heaters. There is no convection section. In addition to the advantages of simple vertical cylindrical heaters, the helical coil heaters are easy to drain. They are limited to smaU-duty applications 5 to 21 Gl/h (5 to 20 10 Btu/h). 

Schematic elevation sec tions of a vertical cylindrical, cross-tube convection heater a horizontal-tube cabin heater and a vertical cylindrical, helical-coil heater are shown in Fig. 27-51. The seven basic designs and some variations of them are pictured and described in the reference cited above and by R. K. Johnson Combustion 50(5) 10-16, November 1978).

A liquid is boiled at a temperature of 360 K using steam fed at a temperature of 380 K to a coil heater Initially the heat transfer surfaces are clean and an evaporation rate of 0.08 kg/s is obtained from each square metre of heating surface. After a period, a layer of scale of resistance 0.0003 nr K/W is deposited by the boiling liquid on the heat transfer surface. On the assumption that the coefficient on the steam side remains unaltered and that the coefficient for the boiling liquid is proportional to its temperature difference raised to the power of 2.5, calculate the new rate of boiling. 

In DI-MS, solid or liquid samples are introduced into a small glass cup and then the cup is inserted into a spring-loaded holder (probe tip). This is heated by a coiled heater up to a maximum of 450 °C thus allowing the sample to be volatilised. The probe can be heated in two different ways ballistic mode or temperature-programme mode. In ballistic mode the probe heats at the maximum rate (150 °C min J) up to the final temperature desired. In the temperature-programme mode the probe heats at a specified rate (from 10 to 100 °C min 1) up to the final set up temperature. 

In the Tervahl T process (LePage et al., 1987 Hydrocarbon Processing, 1998) (Figure 8-9), the feedstock is heated to the desired temperature using the coil heater and heat recovered in the stabilization section and held for a specified residence time in the soaking drum. The soaking drum effluent is quenched and sent to a conventional stabilizer or fractionator where the products are separated into the desired streams. The gas produced from the process is used for fuel. 

Tervahl T process a process analogous to delayed coking (q.v.) in which the feedstock is heated to the desired temperature using a coil heater and held for a specified residence time in a soaking drum see also Tervahl H process. 

Conveying-screen dryers are fabricated with conveyor widths from 0.3- to 4.4-m sections 1.6 to 2.5 m long. Each section consists of a sheet-metal enclosure, insulated sidewalls and roof, heating coils, a circulating fan, inlet air distributor baffles, a fines catch pan under the conveyor, and a conveyor screen (Fig. 12-51). Table 12-23 gives approximate purchase costs for equipment with type 304 staimess-steel hinged conveyor screens and includes steam-coil heaters, fans, motors, and a variable-speed conveyor drive. Cabinet and auxiliary equipment fabrication is of aluminized steel or stainless-steel materials. Prices do not include temperature controllers, motor starters, preform equipment, or auxiliary feed and discharge conveyors. These may add 75,000 to 160,000 to the dryer purchase cost (2005 costs). 

Each channel, led to an Independent analytical unit continuously receiving the ingredients (diluent, reagent) required for development of the analytical reaction, may be fitted with optional separation devices, mixing and reaction coils, heaters, etc., and has its own continuous detection system for sensing the signal yielded by the analyte determined in it. 

Fin heater iig Blast coil — Coil heater es Cooler ibex type)... 

A liquid is boiled at a temperature of 360 K using steam fed at 380 K to a coil heater. Initially the heat transfer surfaces are clean and an evaporation rate of 0.08 kg/s is obtained from each square metre of heating surface. After a period, a layer of scale of resistance... 

Device structures adopted for resistor type sensors in practice, (a) Sintered block, (b) thin alumina tube-coated layer, (c) screen printed thick film, (d) small bead inserted with coil and needle electrodes, (e) small bead inserted with a single coil (heater and electrode), (f) practical sensor element assembling sensor device, metal cap and filter. 

FIGURE 29.4 Isometric view of centrifugal fluidized bed drying system. (1, dryer cylinder 2, drive pulley 3, aspiration feeder 4, feeder blower 5, discharge chute 6, air blower 7, air discharge damper 8, steam coil heater 9, plenum 10, air vent 11, vent port 12, recirculating duct 13, make-up air 14, blower intake). (From Hanni, P.F. et al., J. Food ScL, 41(5), 1172, 1976. With permission.)... 

Mineral-insulated cable heaters are often coiled and used on hot sprue bush-ing/runnerless molding nozzles. The coil heaters are capable of high operating temperatures, up to 815°C. 

The furnace heating coil is wound non-induc-tively to avoid magnetic interactions between the coil and the sample. Coils are made from various materials, such as nichrome (T < 1300 K), platinum (T > 1300 K), platinum-10% rhodium (T < 1800 K) and silicon carbide (T < 1800 K). The furnaces consisting of an infrared (IR) ray heater instead of a standard coil heater are also used. An IR furnace is routinely used up to 1800 K. Using an elliptical reflector or parabolic reflector, IR... 

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