MoSi2 heating element is composed of a self-forming glaze of molybdenum disilicide and silicon dioxide, which has a high density and can be used at furnace temperatures of up to 1800°C. It has a long service life.
ชิ้นส่วนทำความร้อน Mosi2 คืออะไร?
Mosi heating element is a kind of resistance heating element basically made of pure molybdenum Disilicide. It has the ability to withstand oxidation at high temperatures, then due to the formation of a thin and adhesive protective layer of quartz glass on the surface to protect itself out of oxidation.
Therefore, in oxidizing atmosphere, its Max temperature can reach 1900 c and its applicable temperature is 500-1750.
Shape of MoSi2 heating element
The elements U shaped and are most frequently used suspended with the bottom of the “U” down. The element consists of two cold ends (Lu) and a U-shaped hot section (Le). The cold ends are twice the diameter of the hot section and are attached by a weld.
The extremities of the cold ends are metallized with aluminum to provide a low-resistance contact surface to which the electrical connections are made with flat which the electrical connections are made with flat braided aluminum straps.
New and old elements can be use together and in series.
สามารถกระจายพลังงานโหลดสูงได้
สามารถใช้งานต่อเนื่องหรือสลับกันได้
ให้อัตราการเพิ่มอุณหภูมิเตาที่รวดเร็ว
การประยุกต์ใช้ทั่วไป
Laboratory furnaces, testing equipment, and high temperature sintering production furnaces up to 1800°C furnace temperature.
อุณหภูมิระดับ 1900
Max. working temperature 1850 ℃, safety running for operating temp. 1750 ℃
Elements may be used at surface temperature up to 190oºC, at control furnace temperatures up to 1750ºC in oxidizing atmospheres. Lower temperatures are recommended in reducing atmospheres.
High density of SUNSHINE product increases its electrical conductivity. The characters of faster warming and power consumption low, which reduce production cost.
Mosi2 as raw material, the purity is very high.In the manufacturing of mosi2 heating element ,we adopt hi-tech method, it make the element’s surface generate very dense silica membranes,and offer a protection of having thin quartz firm outside when sintering at 1600 Celsius.
When zirconia ceramics dentures is sintering,super pure mosi2 heating element will not bring yellow-dish color on the zirconia unit inside the chamber.
The main material （MoSi2）has a higher purity.
High purity MoSi2 heating element, for various electric furnaces , especially dedicate for high purity furnace.
Max. working temperature 1850 ℃ .
The diameter including hot zone and cold zone are more accurate, avoiding uneven heating and prevent arsing impurities.
more compact protective film, higher adhesive strength with substrate.
Good high-temperature strength,not easy to deformation in use.
When the element temperature is higher than 1700C,the sio2 protective film will be fused because its fusing point is 1710C and the sio2 is fused into molten dropa owing to the action of its surface extension,which cause losing its protective ability .In the oxidizing atmosphere, when the element is continuously used, the protective film forms again.
The MoSi2 heating element must not be used in the temperature between 400C and 700C for a long time, otherwise the element will be cremated under the strong oxidizing function in the low temperature.
ภาระผิว
According to the structure, the temperature and atmosphere in the correct choice of components surface load is the key element to the highest life, based on the thermal radiation components uncrossed circumstance temperature, temperature and surface load components, the shaded part for common surface load -- the temperature range.
The resistivity of element rapidly rises along with the temperature rises , under normal operating condition,generally the element resistance doesn't change with the application time changing.So the old and new elements can be used together.
คุณสมบัติในการต้านทาน
ชิ้นส่วนที่ใช้ในการทำความร้อน Mosi2 เป็นที่ต้านทานที่แปลงพลังงานไฟฟ้าเป็นพลังงานความร้อนตามกฎของ Joules Law W=I2R. W = พลังงานในวัตต์, I = กระแสไฟฟ้าในแอมป์, R = ความต้านทานในโอห์ม
Molybdenum disilicide increases in resistance by a actor of approximately 10 between 20ºC and 1800ºC.Therefore the hot zone temperature must be known before the resistance of the hot zone can be determined.
The mosi2 element is a high temperature element that performs well and gives long service life at its rated temperature of 1700ºC or 1800ºC. Therefore, we recommend designing to element temperatures of 1675ºC for the grade 1700 Grade and 1775ºC for the grade 1800.
The resistance values for 1mm of length for standard element diameters at 1675ºC and 1775ºC are shown on the following Table.
The taper portion of the cold end (Lu) extends into he hot chamber. This cold end taper length varies with the diameter of the element. See Table D to obtain the taper length (g) inside the hot chamber.
10 = minimum recommended vertical distance beneath the element in mm.
0.95 = shortening of the Le to allow for the element to stretch and be a safe distance above the floor.
ข้อจำกัดความยาวสูงสุดในส่วนร้อน:
3/6 และ 4/9 คือสัดส่วนแม็กซิมัม Le สูงสุด = 400 มม.
6/12, 9/18 และ 12/24 Le สูงสุด = 1400 มม.
The 6/12, 9/18 and 12/24 maximum lengths are reduced based on element temperatures over 1600ºC
การออกแบบความยาวโซนร้อนของ mos2
How TO calculate the power on a U-SHAPES mosi2 heating element ?
To compute the power in watts on the mosi2 heating element the length of the hot zone, the surface area of the hot zone, and the watt loading in watts per cm2 must be determined.
To obtain the surface area (SA) of this hot zone in square cm, select from Table C, column 4, the surface area (c) of 1 mm length for the element diameter 3, 4, 6,9, 12, or 24 mm. Multiply this by the total from step 1 (LH).
This number will be the total surface area of the hot zone in square mm. To convert the units from square mm to square centimeters (cm), divide by 100.
When the elements are new (first used) they must be brought to an element temperature of 1200ºC or higher quickly in air. If operated at a surface temperature in the 500ºC to 700ºC range for any length of time before the glaze is formed the elements will be destroyed.
Note: Shifting gear must be done quickly, otherwise high current surges may cause damage.
Installation and Advice
ติดตั้งแนวตั้ง
Under normal temperature, MoSi2 element is very brittleness, while under high temperature it is plasticity. So, the better way for installation if the U Shape element is to hang it vertically, to the furnace top through the support clamping chuck H.
The aim of such way is to avoid putting the mechanical stress directly to the element heat-generating end, or the element will easily be broken.
ปะเก็นรองรับ
Support clamp are applied to &9/18 and &6/12 two kinds of elements respectively. The support clamp supports the whole weight of the element and the position of the element is also determined by it.
The wire connection clamp connecting MoSi2 element is made of aluminum woven wire or multilayer aluninum foil. The steel plate outside it only acts as a clamp and isn't used for electric conduction.
For 6/12 element, single rowing wire is used ,and for &9/18element,double-rowing wire is used ,the end of the lead wire should be a little larger than the linear distance between the element and bus.
The brittleness of MoSi2 heating element is relative more under the usual temperature; it also has plasticity under the high temperature. So you had better hang and erect vertically the "U"-shape element. If you need to erect it horizontally, please choose a support of high-temperature insulating materials. The cone-part of the element must extend inside the furnace.
In order to avoid radiating heat to pass the connector, the distance is not less than 50mm between the low end of connector and the upside of the ceramic brick. The Dia.6 element can't be used of 170A for a long time. The Dia.9 element can't be used of 300A for a long time.
