Other insulation material for induction furnaces
In addition to coil isolation materials, other insulating materials are used for electrical and heat isolation in other parts of the induction furnace. Here, while introducing these materials and their applications, thorough information is provided about their characteristics.
- Isolation padIsolation pad is a set of isolation layers placed between coil and yokes of induction furnace to isolate against each other. Araz Trans Co. offers various types of isolation pads for particular applications to the costumers.Below pictures present various compounds and layers used in isolation pads offered by our company.
Rigid Muscovite/Phlogopite Mica sheet
Nomex
Fiberglass sheet
Rigid Muscovite/Phlogopite Mica sheet
PTFE sheet
NMN sheet : Nomex + Mylar + Nomex
Rigid Muscovite/Phlogopite Mica sheet
Silicon rubber tubes reinforced with fiberglass strips
PTFE sheet
Rigid Muscovite/Phlogopite Mica sheet
Jointing Plate : Aramid fiber with nitrile rubber binder
Araz Trans Company’s innovative design for insulation pads, which is mentioned in the chapter related to “Induction Furnace Yoke”.
- Refractory blocks
Refractory blocks are used as isolator between coil and furnace structure from top and bottom (called upper and lower rings) casted from fibered 50% Alumina in various shapes and sizes. To solidify the block against fragility, metallic materials are added to the batch while casting. Refractory blocks are used in both unit and sectional form. The biggest advantage of the sectional blocks, is to offer empty space between blocks to avoid cracks against expansion duo to furnace heat.
| Common
gender |
item | sign |
|---|---|---|
| Alumina
50% |
High rim | 1 |
| Sections
Special of copper |
furnace coil | 2 |
| Alumina
95% |
wall mass
Coil (Groot 10 or concrete coil) |
3 |
| Alumina
50% |
Lower rim | 4 |
| Roll of compounds
mica base |
Spacer layer
middle |
5 |
| silica mass
or spinel |
Refractory Lining | 6 |
- Refractory spacer
Refractory spacer is used to separate grout coil from the furnace lining. The main responsibility of these spacers is to prevent the melt heat and leaked melt from coil. Moreover, special type of spacers are used as part of the alarm system. Spacers are commonly in the form of rolled flexible Mika in different grades. The upcoming table summarizes various grades of rolled Mika-based spacers offered by Araz Trans Co.
If the spacer from second row is applied, relative melt leak alarm system can be exploited. To do so, after proper furnace reconfiguration and resistance measurement apparatus provided by our company, the instantaneous resistance of the mid spacer layer (non-magnetic steel net) and earthing system(where the melt is connected to the earthing system via an antenna) is measured and monitored to diagnose resistance decrement caused by gradually penetrating melt, approaching mid spacer layer. At certain predefined drop of resistance, previously recognized by the protection system, the alarm goes off and at urgent conditions drops electric supply of the furnace down. This an efficient and low-expense approach for melt leak alarm for furnace.
| line | Layers | Technical Specifications | Dimensions | explanation | Schematic
figure |
||||
| Strength
Electric (KV/mm) |
Minimum
tolerable temperature (W/m/°C) |
Heat
transfer coefficient (°C) |
thickness
(mm) |
width
roll (mm) |
Roll
length (m) |
||||
| 1 | Flexible
phlogopite mica |
18< | 1000 | 0.21 | 0.1-0.6 | 1000 | Max 2.4 | — |  |
| 2 | Flexible
phlogopite mica lace Steel non-magnetic Flexible phlogopite mica |
23< | 1000 | 0.25 | 0.9±0.1 | 1000 | Max 2.4 | This item is
used in furnaces equipped with a special melting leakage system |
 |
| 3 | Phlogopite/
squite mica flexible Glass fiber |
Mus>25
ph>23 |
Mus=1000 ph=1200
|
0.35 | 0.14-0.49 | 500 or
1000 |
Max 300 |  |
|
| 4 | Phlogopite/
squite mica flexible Glass fiber Phlogopite mica Muscovites flexible |
Mus>25
ph>23 |
Mus=1000
ph=1200 |
0.35 | 0.14-0.49 | 500 or
1000 |
Max 300 |  |
|
| 5 | Non woven
fiberglass Phlogopite mica flexible Glass fiber |
>23 | 1200 | 0.35 | 0.40 | 1000 | Max 100 |  |
|
| 6 | Non woven
fiberglass Phlogopite mica flexible Glass fiber Non woven fiberglass |
>23 | 1200 | 0.35 | 0.4&0.5 | 1000 | Max 100 |  |
|
| 7 | Glass fiber
Phlogopite mica/ squite flexible Calcium Silicate |
Mus>25
ph>23 |
1100 | 0.10 | 2.3-3.3 | 500 or
1000 |
12.5
20 25 |
 |
|
| 8 | Glass fiber
Phlogopite mica/ flexible Glass fiber Calcium Silicate |
Mus>25
ph>23
|
1100 | 0.10 | 2.3-3.5 | 500 or
1000 |
12.5
20 25 |
 |
|
| 9 | Calcium
Silicate |
– | 1100 | 0.60 | 1-10 | 500 or
1000 |
10
15 20 25 |
 |
|
| 10 | Glass
fiber Phlogopite mica fine grain flexible Calcium Silicate Alloy aluminium |
>23 | 1100 | 0.10 | 2.4 | according
to order |
This item is
used to prevent the penetration of molten zinc towards the coil |
 |
|
| 11 | Phlogopite
mica fine grain flexible Non woven fiberglass |
>23 | 900 | 0.10 | 0.65
±0.05 |
1000 | 20 |  |
|