CN213179392U - High-temperature bell-jar furnace - Google Patents

Abstract

The utility model discloses a high temperature bell jar furnace, this bell jar furnace are square or circular bell jar formula structure, and its wall body is established to furnace body shell and the fire-resistant inlayer of furnace body by outer and internal fixation, and the furnace side wall is equipped with a plurality of independent admission routes that contain flowmeter, three way connection and intake pipe, and the air vent of intake pipe on the furnace side wall stretches into the furnace chamber in, stretches into a plurality of ventholes of partial pipe wall circumference distribution, and the silicon molybdenum bar is evenly arranged and is hung in the furnace chamber edge, and its length slightly is less than the furnace chamber height. The utility model discloses a many shunts and different flow admit air and make gas circulation in the stove flow, and the venthole that the intake pipe stretched into furnace chamber part pipe wall forms the gaseous perturbation of circumference in the furnace chamber simultaneously, improves the interior high temperature homogeneity of stove in coordination.

Description

High-temperature bell-jar furnace

Technical Field

The utility model relates to a high temperature bell-jar furnace.

Background

The bell jar furnace is a common device for sintering a plurality of materials, and is widely used in the industries of microwave ferrite, zirconia, alumina and other special ceramics due to the flexibility of high temperature and process operation of the electric heating high-temperature bell jar furnace. With the continuous change of market demands, the requirements on the performance, shape, size precision and the like of products are higher, and the requirement on the uniformity of sintering temperature of the products is higher. The existing high-temperature silicon-molybdenum rod heating bell-jar furnace with the temperature of more than 1500 ℃ is generally round or square, U-shaped silicon-molybdenum rods are used for heating and are uniformly distributed and hung on the side surface of a hearth. Because the silicon-molybdenum rod can extend at high temperature, the length of the heating end of the selected silicon-molybdenum rod is shorter than the height of the hearth, and a certain extending gap is kept between the heating end and the lower part, as shown in figure 1. Therefore, the phenomenon that the upper temperature is high and the lower temperature is low is easily formed, the upper and lower temperature difference is generated in the furnace chamber, and the higher the temperature is, the larger the temperature difference of the high-temperature furnace is, and the higher the temperature is, the temperature is, the higher the temperature is, the temperature is dozens of degrees. Usually, the nominal value of the high-temperature sintering furnace is +/-5 ℃ above 1500 ℃, and the requirements of some materials with high temperature uniformity are difficult to meet.

To improve the above situation, many improvements are made to improve the high temperature uniformity, such as: in order to ensure the uniformity of the thermal field of the hearth, the thermal resistance around the hearth is kept consistent during design; the heat dissipation at the top of the hearth is large, and the top heat-insulating layer is generally thickened properly, and the like. The method for improving the temperature uniformity of the electric heating high-temperature bell jar furnace and the application thereof are characterized in that a special temperature region, namely a lower compensation independent temperature region, of the electric heating high-temperature bell jar furnace hearth is designed according to the technical scheme of Chengzhou peaks and the like (Chengzhou peaks, equal and flat, and the temperature uniformity of the electric heating high-temperature bell jar furnace is improved and the application thereof is ceramic, 3 months in 2015, P27), so that the upper and lower temperature difference of the. The method comprises the following steps: a special silicon-molybdenum rod heating element is additionally arranged in a kiln hearth, so that the total length of the heating element is not changed, the hot end of the heating element is shortened, the cold end of the heating element is enlarged, namely, the longer cold end part of the heating element extends into the hearth, and a temperature control point is additionally arranged at the lower end of the hearth to control the temperature of a lower special temperature zone. When the special heating element works, as the heating end is positioned at the lower part of the section of the hearth, the main power of the heating element is released at the lower part of the hearth, the heating power at the lower part of the hearth is correspondingly increased, and the actual temperature of the lower part is improved. Before improvement, the maximum temperature difference in the bell jar furnace with the conventional structure is 20 ℃ (1653 ℃ maximum and 1633 ℃ minimum), the maximum temperature difference in the bell jar furnace after the special temperature zone is increased is +/-3 ℃ (1652 ℃ maximum and 1646 ℃ minimum), and the temperature uniformity of the bell jar furnace is obviously improved.

The Ouyang-Hope furnace (patent No. 201811277258.0: a bell-type furnace) is characterized in that an air inlet is arranged on a movable furnace door, protective atmosphere enters a furnace chamber through the air inlet on the side wall of the furnace chamber, and the protective atmosphere access device based on the existing bell-type furnace is designed by arranging the air inlet only on the side wall of the furnace chamber. Although simple structure, maintenance are convenient for this mode of admitting air, nevertheless be unfavorable for temperature homogeneity and atmosphere field homogeneity, under the big air input condition that lasts, cause easily to be close to furnace inner wall position and near the admission point temperature lower, protective atmosphere concentration is higher, and furnace middle part position and bottom temperature are higher, protective atmosphere concentration is lower to lead to product quality relatively poor. The bell jar furnace is suitable when the bottom and the top are high due to the fact that the air inflow of the side wall of the bell jar furnace is very large, but is not suitable if the air inflow of the air inlet of the furnace wall is not large, because the furnace door is arranged at the lowest part (namely bottom air inlet), the bottom temperature is the lowest originally, air is then introduced, the temperature of the bottom in the furnace is lower, and the temperature difference is further increased. In addition, the furnace door is a movable device, air enters the furnace door, the complexity of the equipment is increased, and the safety and reliability of the equipment are reduced.

SUMMERY OF THE UTILITY MODEL

An above-mentioned not enough to prior art, the utility model aims to provide a high temperature bell jar stove adjusts the interior high temperature homogeneity of stove through the control of the gas circuit that admits air distribution, intake pipe design and different flow.

In order to realize the purpose of the utility model, the utility model adopts the technical scheme that:

a high temperature bell jar furnace comprising: the bell jar furnace is of a square or round bell jar type structure, the wall body of the bell jar furnace is fixedly arranged into the furnace body shell and the furnace body fireproof inner layer from outside to inside, the side wall of the furnace is provided with a plurality of independent air inlet passages containing the flowmeter, the three-way joint and the air inlet pipe,

the air inlet pipe extends into the furnace cavity through vent holes uniformly distributed on the side wall of the furnace, and a plurality of air outlet holes are uniformly distributed in the circumferential direction of the pipe wall of the part extending into the furnace cavity;

the silicon-molybdenum rods are uniformly distributed and hung on the edge of the furnace chamber of the bell jar furnace, and the length of the silicon-molybdenum rods is slightly smaller than the height of the furnace chamber.

Further, the intake air of the intake passage may be homologous and the flow rate of the intake air may be controlled by the flow meter, respectively.

Furthermore, the air inlet passage is provided with three paths from top to bottom, and the air inlet flow ratio is 2: 3: 5.

further, the material of the air inlet pipe is selected from zirconia or corundum.

Furthermore, the furnace door is a lifting structure fixedly provided with a furnace door fire-resistant inner layer and a furnace door shell from bottom to top, the upper layer cross section of the furnace door fire-resistant inner layer is the same as the cross section of the furnace chamber, and the lower layer cross section is larger than the cross section of the furnace chamber.

Furthermore, the material of the furnace body fire-resistant inner layer and the furnace door fire-resistant inner layer is selected from one of ceramic fiber, corundum brick, corundum mullite brick and alumina fiber compressed cotton.

Furthermore, the silicon-molybdenum rods are U-shaped silicon-molybdenum rods which are uniformly distributed along the edge of the bell jar furnace chamber and can extend into the heating zone at the bottom of the bell jar furnace chamber.

Compared with the prior art, the beneficial effects of the utility model reside in that:

(1) the gas in the furnace circularly flows by adopting multi-branch gas inlet and different flow control gas inlet, the temperature uniformity in the furnace is improved, and the temperature difference of an effective working area in the furnace is lower than the prior nominal value (+/-5 ℃).

(2) The gas inlet end of the gas inlet pipe extends into the furnace cavity and extends into the gas outlet holes distributed on the circumferential direction of part of the pipe wall, so that circumferential gas micro-disturbance is formed in the furnace, and the high-temperature uniformity in the furnace is improved.

Drawings

FIG. 1 is a schematic view of a conventional bell jar furnace;

FIG. 2 is a schematic structural view of a middle-high temperature bell jar furnace according to the present invention;

FIG. 3 is a partial enlarged view of portion A of FIG. 2;

the drawings illustrate the following:

1-flow meter, 2-three-way joint, 3-air inlet pipe, 4-furnace body shell, 5-furnace body fire-resistant inner layer, 6-silicon-molybdenum rod, 7-vent hole, 8-furnace door, 9-furnace door fire-resistant inner layer, 10-furnace door shell and 11-air outlet hole.

Detailed Description

The invention will be described more fully and in detail with reference to the accompanying drawings and examples:

as shown in figure 1, the furnace body of the prior bell-jar furnace consists of a furnace door 8, a furnace body shell 4, a furnace body fireproof inner layer 5, a silicon-molybdenum rod 6 and a vent hole 7, the air inlet channels are homologous, a flowmeter 1 controls a plurality of air inlet channels, and the opening and the closing of the furnace door 8 are in a lifting mode. The vent holes 7 are provided with three rows of four holes, the four holes are uniformly distributed, the total number of the vent holes is 12, and the vent holes 7 are usually used for removing original gas in the furnace to realize atmosphere protection. The silicon-molybdenum rods 6 are heating rods, and the number thereof is set according to the size of the furnace chamber. The refractory inner layer is made of a suitable material according to furnace temperature and environmental protection requirements, so that the heat preservation function is realized.

As shown in fig. 2 and 3, the high temperature bell-jar furnace of the present invention is a square or round bell-jar structure, the wall body of which is fixedly arranged from outside to inside as a furnace body shell 4 and a furnace body fireproof inner layer 5, the furnace side wall is provided with a plurality of independent air inlet passages containing a flowmeter 1, a three-way joint 2 and an air inlet pipe 3, the air inlet pipe extends into the furnace cavity through air vents 7 uniformly distributed on the furnace side wall, and a plurality of air outlet holes 11 are uniformly distributed on the circumferential direction of the pipe wall of the furnace cavity; the silicon-molybdenum rods 6 are uniformly distributed and hung on the edge of the furnace chamber of the bell jar furnace, and the length of the silicon-molybdenum rods is slightly less than the height of the furnace chamber; the furnace door 8 is a lifting structure which is fixedly provided with a furnace door fire-resistant inner layer 9 and a furnace door outer shell 10 from bottom to top, and the lower layer cross section of the furnace door fire-resistant inner layer 9 is larger than the cross section of the furnace chamber; the silicon-molybdenum rods are U-shaped silicon-molybdenum rods which are uniformly distributed along the edge of the furnace chamber of the bell jar furnace and can extend into the heating zone at the bottom of the bell jar furnace.

In one embodiment, the intake passage is provided as a three-way intake source, and the intake flow rates can be controlled individually by the flow meter 1. The ventilation is carried out by adopting a plurality of gas paths with different flow rates, the vent holes 7 are provided with three rows, each row is provided with four holes which are uniformly distributed, the vent holes 7 are usually used for driving away original gas in the furnace to realize atmosphere protection, the combination of gas inflow with different flow rates is set according to the temperature condition in the furnace before ventilation, the temperature difference in the furnace is reduced through the flow of the gas, and the temperature in the whole furnace is uniform. In addition, the air inlet end of the air inlet pipe 3 extends into the air outlet holes 11 distributed on the circumferential direction of the pipe wall of the furnace chamber, so that circumferential micro-disturbance of air is formed in the furnace, and the temperature uniformity in the furnace is improved.

In one embodiment, the material of the inlet pipe 3 is selected from zirconia or corundum.

In one embodiment, the furnace body fire-resistant inner layer 5 and the furnace door fire-resistant inner layer 9 are both made of ceramic fibers, so that the heat preservation function is realized.

The bell jar furnace body structure shown in fig. 2 and 3 is adopted for heating, taking 3 rows of air inlets as an example, the effective heating area of a furnace chamber is 300mm multiplied by 300mm, the sintering temperature is 1550 ℃, and the flow meters are sequentially marked as follows from top to bottom: 1, 2 and 3, the air inlet flow rates of the 1, 2 and 3 flowmeters are 2, 3 and 5 (the unit is L/min), 15 temperature measuring rings are placed in the effective heating area, an upper layer, a middle layer and a lower layer are measured, 5 temperature measuring rings (distributed on the peripheral edge and the middle part) of each layer are measured, the temperature is kept for 3 hours, and the temperature difference of the effective working area in the furnace is lower than the existing nominal value (+/-5 ℃).

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. It will be readily apparent to those skilled in the art that various modifications to these embodiments and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments. Those skilled in the art should appreciate that, in view of the principles of the present invention, modifications and variations may be made without departing from the scope of the invention.

Claims (7)

1. A high temperature bell jar furnace comprising: a flowmeter (1), a three-way joint (2), an air inlet pipe (3), a furnace body shell (4), a furnace body fireproof inner layer (5), a silicon-molybdenum rod (6) and a furnace door (8),

the bell-jar furnace is of a square or round bell-jar structure, the wall body of the bell-jar furnace is fixedly arranged from outside to inside into a furnace body shell (4) and a furnace body fireproof inner layer (5), and the side wall of the bell-jar furnace is provided with a plurality of independent air inlet passages containing a flowmeter (1), a three-way joint (2) and an air inlet pipe (3);

the air inlet pipe (3) extends into the furnace cavity through vent holes (7) uniformly distributed on the side wall of the furnace, and a plurality of air outlet holes (11) are uniformly distributed on the circumferential direction of the partial pipe wall extending into the furnace cavity;

the silicon-molybdenum rods (6) are uniformly distributed and hung on the edge of the furnace chamber of the bell jar furnace, and the length of the silicon-molybdenum rods is slightly smaller than the height of the furnace chamber.

2. A high temperature bell jar furnace according to claim 1 wherein the inlet air homology of the inlet air channels is separately controllable via the flow meter (1) for inlet air flow.

3. The high-temperature bell jar furnace as claimed in claim 1 or 2, wherein the inlet passage is three-way from top to bottom, and the inlet flow ratio is 2: 3: 5.

4. a high temperature bell jar furnace according to claim 1 wherein the material of the inlet pipe (3) is selected from zirconia or corundum.

5. A high temperature bell jar furnace according to claim 1, wherein the furnace door (8) is a lifting structure with a furnace door inner refractory layer (9) and a furnace door outer shell (10) fixed from bottom to top, the lower cross section of the furnace door inner refractory layer (9) is larger than the furnace cavity cross section, and the upper cross section is the same as the furnace cavity cross section.

6. A high-temperature bell jar furnace according to claim 1 or 5, characterized in that the material of the furnace body fire-resistant inner layer (5) and the furnace door fire-resistant inner layer (9) are selected from one of ceramic fiber, corundum brick, corundum mullite brick and alumina fiber compressed cotton.

7. A high temperature bell jar furnace according to claim 1, wherein the silicon-molybdenum bars (6) are U-shaped silicon-molybdenum bars evenly distributed along the edge of the bell jar furnace chamber and can extend into the heating zone at the bottom thereof.

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