Thermal insulation system selection

While thermal insulations are selected first for their resistance to heal flow, their other properties need evaluation for each application. Hence there is no "best" insulation because a material well suited to one service may be poorly suited to another. Economics must be studied in detail because in some services the cost of a highly efficient material per unit of thickness may be overcome by additional thickness of a less efficient material, provided there is room for the grealet thickness. All properties of materials must he considered for each exposure, even within the same system. Recognize that when different materials are used or different parts nl insulation sv -.tents that arc close together, the probability of using the wrong material on a particular surface is increased appreciably. Unless there is specific reason for wide use ol multiple types of materials, it may be prudent to accept some compromises of properties. 

Foam thermal insulation was selected for the cable pipe because of its low cost and high reliability, as demonstrated by its use in LNG piping systems. Possible degradation of its insulating quality could be caused by the infiltration of water... 

The materials identified in Table 23 can be used as multilayer structures that utilize the strongest characteristics of each layer of material. Nearly all coatings are multilayer systems that combine titanium nitride for lubricity and galling resistance alumina for chemical inertness and thermal insulation and titanium carbide, as well as titanium carbonitride, for abrasion resistance. Selecting the optimal combination of materials depends on the type of machining operation, the material to be machined, and other factors. Criteria for such a selection are summarized in Table 25. 

Recall that Table 7.1 provided a range of thermal effectiveness for the more common insulation materials. However, from the previous sections it should be evident that the most thermally resistant material is not always the most adequate for a given application. Cryogenic systems typically have constraints other than thermal-insulating capacity that determine the selection of an insulant, such as the desire for a low-density material for insulating a space rocket. Thus, Table 7.1 should not be used exclusively in selecting an insulation, but just to show the relative thermal resistances. Table 7.5 presents a more qualitative yet detailed analysis of the more commonly used cryogenic insulations. 

The end result of these waveshapes being appUed to the motor terminals is increased stress on the insulation system. Since these waveshapes do not exist in sinewave applications it is clear that their effect has not been considered in standard AC motor insulation systems. The motor insulation system must be capable of withstanding both the increased thermal stress as well as the capadtively coupled currents and voltage stresses. Appropriate selection of... 

A tile stove heating insert, illustrated by Figure 5, with a thermal capacity of 10 kW, representing the state of the art of wood log combustion systems was selected as a test stove. The firing principle of the stove can be described as "backside downdraft". It consists of two spatially separated, well insulated reaction zones for gasification of the wood fuel and burnout of the combustible gases, respectively. 

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