Thermal conductance is to point to inside unit time, below unit temperature gradient, the quantity of heat that place of unit area sample passes. According to Henan fireproof material factory introduces the thermal conductance of fireproof material to be versed in to high temperature heat the design of equipment is indispensable important data. Good to those requirement heat proof quality light simple fireproof stuff and function of requirement heat conduction separate stuff of structure of blaze heating furnace goodly, its thermal conductance is attached most importance to especially should. Use the material step with small thermal conductance to build boiler setting to be able to reduce ply or hot loss; Use the stuff with old thermal conductance to regard as lie between blaze board and heat exchanger canal, can raise the chamber of a stove or furnace temperature and pass thermal efficiency.
According to Henan introduction of fireproof material factory determines the law of methodological cent stable state of thermal conductance and law of blame stable state two kinds.
Stable state law uses instrument of flat heat conduction normally, it is main by heat board, dead plate, protect the component composition such as heat board and calorimeter. In test of stable state law, in waiting for test sample to stabilize temperature field at, determine to be led through the thermal current on sample unit area.
Stable state law is classical method, ever was included a level by each country. Its main drawback is to check time to grow, influencing factor is much. The advantage that is not stable state law is to measure handy, fast.
Standard (ISO8894, 1) determine fireproof material thermal conductance and Chinese standard (GB/T5990, 1986) determine refractory products thermal conductance uses boarding heat insolation the law of crossed hot line in be not stable state law. Its principle is to measure direction of edge sample length to bury it is certain to be set in heat source of form of sample central line to be in the temperature rise inside time. Follow the change of time through soldering to measure hot line temperature in the thermocouple of hot line midpoint. The temperature change of this line is the function of thermal conductance of the material that be measured namely.
Chinese standard (GB/T17106, 1997) use law of parallel hot line to determine the thermal conductance of fireproof material. Law of parallel hot line is to measure span to bury set between two test block to regulation of line heat source is apart from and set locally a kind of trends that temperature lifts place undertakes measures a way. Sample package heats to issue heat preservation in this temperature to formulary temperature inside furnace, direction of length of reoccupy edge sample is buried those who be set in sample is linear conductance body (hot line) undertake local heating, the hot line carries foregone and constant the electric current of power, go up in time namely and the power on direction of test block length is changeless. Thermocouple puts the place that provides in line leaving heat, and parallel at the hot line. From put through the instant that adds thermocurrent begins, thermocouple begins to measure temperature rise to follow the change of time, the function of this temperature rise and time is the thermal conductance of the sample that be measured.
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