Insulation, glass wool

The reaction should be conducted behind appropriate shielding. Maintaining the internal temperature of the reaction mixture at 50°C is imperative in order to obtain good yields of 1 [the bp of vinyltrimethylsilane (55°C) should not be exceeded]. Alternatively, the submitters employed a sand bath and the whole assembly was insulated with glass wool. The checkers found that temperature control was more easily achieved with an oil bath and did not employ glass wool insulation. 

Urea-formaldehyde 19 Binder for Glass Wool Insulation 15... 

While their largest use is as adhesives for outdoor plywood and glass wool insulation, they provide a group of compressionmolding fiber-reinforced plastics which meet high engineering performance requirements (Table 15.16). 

Steam a T i = 320°C flows in a cast iron pipe (k = 80 W/m °C) whose inner and outer diameters are D, = 5 cm and Dj 5.5 cm, respectively. The pipe is covered with 3-cm-thick glass wool insulation with k = 0.05 W/m C. Heat is lost to the surroundings at - 5°C by natural convection and radiation, with a cyimblned heat transfer coefficient of hj = 18 W/m °C. Taking the heat transfer coefficient inside the pipe to be hi = 60 W/m °C, determine the rate of heat loss from the steam per unit length of the pipe. Also determine the temperature drops across the pipe shell and the insulation. 

A 2-m X t,5-in section of wall of an industrial furnace burning natural gas is not insulated, and the temperatuce at the outer surface of this section is iiieasuied to be 80°C. The tem-peralure of the furnace room is 30 C, and the combined convection and radiation heat transfer coefficient at the surface of the outer furnace is 10 W/m °C, It is proposed to insulate this section of tiie furnace wall with glass wool insulation (A = 0,038 W/m -" C) in order to reduce the heat loss by 90 percent, Assuming the outer surface temperature of the metal section still remains at about 80°C, determine the thickness of the insulation that needs lobe used. 

Chilled water enters a thin-shelled 5-cni-diameter, l50-m-long pipe at TC at a rate of 0,98 kg/s and leaves at 8°C. The pipe is exposed to ambient air at 30°C with a heal transfer co efficient of 9 W/m °C. If the pipe is to be insulated with glass wool insulation (k = 0.05 W/m °C) in order to decrease the temperature rise of water to 0.25°C, determine the required thickness of the insulation. 

E. H. Sargent Co. Catalog No. S-35955). This furnace has a hot zone of 8f in. and a maximum temperature of 1450°C. Because of the short heating length, the Vycor tube was packed with copper turnings over its entire length to prevent condensation of coumalic acid in the cooler parts of the tube. Glass wool insulation w used at both ends of the furnace to prevent heat loss. 

Example. A column 25 ram in diameter and 5 m long has been covered with channel shaped sections of glass wool insulation (A = 0.055 kcal/m h °C) with a wall thickness of 62.5 mni. The internal temperature is 76.6°C, room temperature 18°C. Reijuired the heat loss. By formula (162) ... 

Provision of external cladding by aluminium sheets on the existing mineral or glass wool insulation in a leak-proof manner can further reduce the loss of heat from surfaces of equipments (reactors, heat exchangers) and hot ducts (larger-diameter pipes). 

They dominate the field of wood adhesives and represent one of the largest volumes of any synthetic adhesive. Phenolics are also among the lowest-cost adhesives and may be formulated as water dispersions, to allow penetration into the cell structure of wood which is important for the formation of permanent bonds. Beyond the wood and wood products area, unmodified phenolics are used mainly as primers, to prepare metal surfaces for bonding, and as binders, for such varied products as glass wool insulation mats, foundry sand, abrasive wheels, and brake lining composites. Phenolics are supplied either as one-component, heat-curable liquid solution, as powder, or as liquid solution to which catalysts must be added. The curing mechanisms are different for these two groups. "... 

Calculate the lagging of the double hairpin heat exchanger assuming a heat conductivity coefficient, k, of the glass wool insulation material of 0.15 W/m°C and a heat transfer coefficient ha (W/m C) from the Al-cladding to the ambient air of 25 W/m C. 

Other applications include binders for molding materials such as electrical plugs or dinnerware, binders for mineral and glass wool insulation and roofing, flame-retarding agents, and leather auxiliaries. 

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