Indirect resistance furnaces measurement, control and recording of electric equipment basic technical conditions

1 thermocouple:
Selected by resistance furnace thermocouple should meet its requirements, the indexing should be consistent with the provisions of the relevant national standards, have appropriate protection tube thermocouple, thermocouple wire in order to avoid the impact of media by the furnace. Unless otherwise specified or required (see section 9.2), the length of the industrial resistance furnace thermocouple leads should not be less at 7.5m. The material of the thermocouple leads should be the same as the thermocouple, or use the thermoelectric properties of the thermocouple wire compensation wire.
Two temperature instruments with:
Resistance furnace temperature control area shall be provided with instructions, control and record the temperature of the furnace temperature necessary instrumentation. Temperature meter shall be marked on the indexing number has been equipped with a thermocouple. In addition to making minor adjustments, the thermocouple lead wire or the compensation wire length should not affect the accuracy of the instrument.
3 temperature meter types and their accuracy:
The technical level of resistance furnace with temperature meter divided into the following three categories:
C-level resistance furnace should be equipped with an accuracy of 0.25 or better instrument, the instrument should have automatic compensation of the thermocouple reference junction temperature.
Class B or Class A resistance furnace should be equipped with an accuracy of 0.5 or better instrument.
When otherwise required or demanded (see section 9.2), A-level resistance furnace can also be equipped with an accuracy of one meter.

Experimental furnace heating wire classification

Including iron-chromium alloy heating wire and nickel-chromium alloy heating wire into two categories. The former is a ferritic alloy tissue, which are austenitic alloys. In addition, there are some special purposes such as tungsten filament heating alloy wire, molybdenum wire and other laboratory furnace according to different purposes, to different temperatures, choose a different electric wire.
Laboratory furnace with electric wire electric iron chrome aluminum alloy material is characterized by:
1. Use of high temperature, such as HRE iron-chromium alloy wire in the atmosphere maximum temperature up to 1400 ℃, which is the laboratory furnace maximum temperature can reach 1,400 degrees, if you need to design more than this temperature laboratory furnace, you need to select another The electric wire;
(2) long life;
3 Allow the surface of the load is large;
4 good oxidation resistance, and its oxidation to generate AI2O3 film has good chemical resistance and high electrical resistivity, specific gravity less than nickel-chromium alloy, high resistivity.
5 sulfur resistance is good;
6 prices significantly lower than nickel-chromium alloy;
7 disadvantage is that as the temperature increases, the performance of plastic, high temperature strength is low.
Laboratory furnace nickel-chromium heating wire is characterized by:
1, high strength at high temperatures;
(2) long-term use and then cooled down, the material does not become brittle;
3 fully oxidized nickel alloy ming the radiation rate ratio Fe-Cr alloy high;
4 non-magnetic;
5 In addition to the atmosphere of sulfur, the better corrosion resistance.
Laboratory furnace alloy heating wire shortcomings
Alloy heating wire is the most widely used, the largest amount of heating materials. Its disadvantage is its working state is very high temperatures (hot state), prone to oxidation in air blown reaction; electrothermal energy conversion aspects from analysis due to energy loss leaving visible light generating section; electric wire is often Use a spiral state, power is generated when inductance effects.

Industrial furnace with ceramic fiber products Features

1, the installation process, the lifting of blanket folded after bundling will have an enormous stress, crowding each other sealed without leaving any gaps.
2 ceramic blanket high-dimensional elastic deformation of the furnace shell can make to reduce construction costs. Meanwhile, the different components inside the furnace can make different changes due to heat generated by the gap.
3, due to light weight, low heat capacity (only for light and light resistant refractory lining of 1/10), can significantly reduce the furnace energy consumption in the operation control.
4, elastic fiber blanket can withstand mechanical force.
5, with the ability to resist any thermal shock.
6, the lining of the body without drying and curing, lining construction is completed ready for use.
7, chemical stability. In addition to phosphoric acid, hydrofluoric acid and alkali, the other acids, alkali, water, oil, steam, not being eroded.

The range of application of the high-temperature furnace

High-temperature furnace is the national standard energy-saving cycle operating furnace, mainly for steel products, a variety of metal parts normalizing, hardening, annealing heat treatment purposes, or diamond cutting blade for high-temperature sintering purposes.
High-temperature furnace Precautions
In addition to doing the experiment, do not stay in the area of ??high-temperature furnace tube.
Experimental work is completed, if not continue to use special gas, close reserved N2 flow tube maintained at the standby temperature and see if there are other power the customs not related, such as: cleanhood light, boiling acid with a small electric furnace or other, please turn off.
Dealing with HF, gloves, such as accidentally ran into HF, immediately flush with calcium gluconate plus 2% water, rub the wound 15 '.
Quartz glass products be used with care, so as not to rupture, causing severe cuts.
Avoid inhalation of smoke from the stove or treatment tank of gas.
Potassium cyanide (KCN) can not be set, because the two can produce highly toxic KCN gas mixed with acids.
Once found to interfere with the security of things, please immediately notify the relevant personnel (technicians).
Please save the amount of pure water.
Broken wafer, filter paper, cotton swabs ....... Do not fall into the drainage holes at the bottom of the cleaning tank, so as not to cause the floor to waterlogging due to poor drainage.
Length of putting the front end, not to facing up to avoid contamination.
Wafer into the baked mouth, to undertake the holder of the boat, do not touch the tube mouth, to avoid contamination of the furnace tube.