A protective device for firing graphite crucibles in a tunnel kiln.
By designing a closed transition space and a heating buffer device at the kiln outlet of the tunnel kiln, the temperature fluctuation and clamping problems of graphite crucibles when exiting the kiln were solved, achieving high yield production and cost reduction of graphite crucibles.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHIJIAZHUANG ZHONGDONG CARBON CO LTD
- Filing Date
- 2025-08-19
- Publication Date
- 2026-06-30
AI Technical Summary
Graphite crucibles are prone to cracking and chipping due to sudden temperature changes when exiting the kiln, and are also easily damaged during clamping, affecting the production qualification rate and efficiency.
Design a protective device for the kiln outlet of a tunnel kiln used for firing graphite crucibles, including a shell, a funnel-shaped sand hopper and a heating tube. By forming a closed transition space at the kiln outlet, the device utilizes the accumulation of hot air and the heating sand to buffer temperature changes, and ensures temperature stability and anti-clamping ability through heat-insulating flaps and counterweight limiting rods.
It effectively reduces temperature fluctuations in graphite crucibles, enhances anti-clamping ability, improves production qualification rate, and reduces production costs.
Smart Images
Figure CN224434972U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of graphite crucible production equipment, specifically relating to a kiln exit protection device for firing graphite crucibles in a tunnel kiln. Background Technology
[0002] Graphite crucibles are widely used in metal smelting, material calcination, and other processes due to their excellent high-temperature resistance, thermal conductivity, and chemical stability. The crucible blanks are formed by firing in a tunnel kiln. The tunnel kiln uses continuous heating, holding, and cooling processes to complete the graphitization reaction of the crucible blanks and form a stable structure.
[0003] Currently, after the graphite crucibles are fired in the tunnel kiln, although they undergo a gradient cooling stage inside the kiln, they still retain a relatively high residual temperature when exiting the kiln. When the graphite crucibles are directly exposed to room temperature after exiting the kiln, the temperature drops rapidly, generating significant thermal stress inside the crucible and leading to defects such as cracking and edge chipping, severely affecting the yield of the finished product. Currently, the most common method is to use natural slow cooling within the tunnel kiln. However, this places higher demands on the length of the tunnel kiln and results in longer time spent inside the kiln, slowing down the production pace and restricting production efficiency.
[0004] Furthermore, after exiting the kiln, the graphite crucible needs to be transferred using a clamping device for bottom leveling and inner wall surface machining. During the clamping process, the outer wall is subjected to stress, which can easily cause the graphite crucible to break.
[0005] Therefore, how to effectively mitigate temperature fluctuations and improve anti-clamping ability during the kiln exit stage of graphite crucibles has become a key technical issue for improving the production qualification rate and reducing production costs of graphite crucibles. Utility Model Content
[0006] To address the problems existing in the prior art, this utility model provides a kiln exit protection device for firing graphite crucibles in a tunnel kiln, which can effectively reduce temperature fluctuations, improve anti-clamping ability, increase the production qualification rate of graphite crucibles, and reduce production costs.
[0007] The specific technical solution adopted in this utility model is as follows:
[0008] A protective device for firing graphite crucibles in a tunnel kiln is provided. The device is connected to the kiln outlet of the tunnel kiln and covers the conveyor track of the tunnel kiln. It includes a shell and a sand hopper installed on the top of the shell. The sand hopper is funnel-shaped and has a sand outlet. The graphite crucible passes under the sand outlet via the conveyor track. The sand hopper injects sand into the graphite crucible. A heating tube is also installed inside the sand hopper. The input end of the shell is connected to the kiln outlet of the tunnel kiln, and the output end of the shell is equipped with a heat-insulating flap.
[0009] The heat-insulating flap is hinged to the shell via a hinge shaft. The plane of the hinge shaft of the heat-insulating flap is higher than the plane of the upper edge of the graphite crucible. The heat-insulating flap is lifted by the movement of the graphite crucible and swings around the hinge shaft.
[0010] The bottom of the heat-insulating flap is provided with a counterweight limiting rod, and the left and right ends of the counterweight limiting rod extend outside the output end of the shell and form abutment interference with the shell.
[0011] The sand hopper is provided in two sets. A storage bin is provided above the sand hopper. The bottom of the storage bin is connected to the sand hopper. A spiral stirring shaft driven by a drive motor is also provided inside the sand hopper. The spiral stirring shaft is located above the sand outlet. The sand outlet has a tubular structure. An opening flap is provided inside the sand outlet. The opening flap is connected to an opening motor via a drive shaft.
[0012] The housing is provided with inspection windows, which are respectively provided on the left and right side walls of the housing.
[0013] The beneficial effects of this utility model are:
[0014] This utility model uses a shell cover to fasten above the conveyor track, with the input end directly connected to the kiln outlet of the tunnel kiln and the output end equipped with a heat-insulating flap, to surround the kiln outlet of the tunnel kiln and form a relatively closed transition space. The hot air during kiln opening accumulates in the shell, increasing the temperature inside the shell and reducing the direct impact of cold air from the outside on the graphite crucible.
[0015] Furthermore, by raising the initial temperature of the sand through the heating tube, the heat capacity is increased, mitigating the drastic cooling after the graphite crucible is removed. Additionally, the sand filling adheres tightly to the inner wall of the crucible, forming a uniform internal support structure. When the clamping device applies force to the outer wall of the graphite crucible, the sand disperses the stress, preventing deformation or breakage caused by excessive localized force. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the structure of this utility model;
[0017] Figure 2 for Figure 1 A schematic diagram of the left-side view;
[0018] Figure 3 for Figure 2 A cross-sectional schematic diagram;
[0019] In the attached diagram, 1 is the conveying track, 2 is the shell, 3 is the sand hopper, 4 is the sand outlet, 5 is the heating pipe, 6 is the heat-insulating flap, 7 is the hinge shaft, 8 is the counterweight limit rod, 9 is the storage bin, 10 is the drive motor, 11 is the spiral stirring shaft, 12 is the opening flap, 13 is the opening motor, and 14 is the inspection window. Detailed Implementation
[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:
[0021] Specific implementation examples Figure 1 As shown, this utility model is a protective device for the kiln outlet of a tunnel kiln used for firing graphite crucibles. It is connected to the kiln outlet of the tunnel kiln and covers the conveying track 1 of the tunnel kiln. It includes a shell 2 and a sand hopper 3 set on the top of the shell 2. The sand hopper 3 is funnel-shaped and has a sand outlet 4. The graphite crucible passes under the sand outlet 4 via the conveying track 1. The sand hopper 3 injects sand into the graphite crucible. A heating tube 5 is also set inside the sand hopper 3. The input end of the shell 2 is connected to the kiln outlet of the tunnel kiln, and the output end of the shell 2 is equipped with a heat-insulating flap 6.
[0022] The shell 2, with an n-shaped structure, covers the conveyor track 1 and connects to the kiln outlet of the tunnel kiln, forming a relatively enclosed transition space. This space can accumulate the hot air overflowing from the kiln outlet and effectively prevent direct contact between the low-temperature outside air and the graphite crucible, creating a mild transition environment for the graphite crucible and reducing the impact of sudden temperature changes on it. The sand hopper 3 can inject sand into the graphite crucible as it passes through. The sand is preheated by the heating pipe 5, and the thermal buffering effect of the sand further slows down the overall cooling rate of the graphite crucible, preventing thermal stress cracking caused by excessively rapid cooling.
[0023] The heating tube 5 inside the sand hopper 3 preheats the sand, preventing excessive local temperature differences caused by low-temperature sand entering the graphite crucible and ensuring a more stable temperature buffering effect. Furthermore, the heating tube 5 runs through both sets of sand hoppers 3, allowing each hopper 3 to be filled halfway with sand. This helps reduce the volume of a single hopper 3, decreases the amount of sand per hopper, and increases the preheating speed. Additionally, the heating tube 5 can be connected in series with the exhaust pipe of the tunnel kiln, utilizing the high-temperature exhaust gas from the tunnel kiln for heating, thus improving energy utilization.
[0024] The heat-insulating flap 6 installed at the output end of the housing 2 can help form a relatively enclosed space, reduce heat loss inside the housing 2, and maintain the temperature stability of the transition space.
[0025] Furthermore, such as Figure 1As shown, the heat-insulating flap 6 is hinged to the shell 2 via the hinge shaft 7. The plane of the hinge shaft 7 of the heat-insulating flap 6 is higher than the plane of the upper edge of the graphite crucible. The heat-insulating flap 6 is lifted by the movement of the graphite crucible and swings around the hinge shaft 7.
[0026] The heat-insulating flap 6 is hinged to the shell 2 via a hinge shaft 7, with the plane of the hinge shaft 7 higher than the upper edge of the graphite crucible. This allows the graphite crucible to move and open the heat-insulating flap 6 during transport without additional power, simplifying the device's power structure, reducing the risk of failure, and effectively preventing accidental opening. Since the tunnel kiln uses kiln cars for the firing and transport of individual graphite crucibles, the spacing between them is relatively large, ensuring that the heat-insulating flap 6 will not interfere with the next graphite crucible when it falls. After the graphite crucible leaves, the heat-insulating flap 6 can quickly return to its original position under its own weight, thus maintaining the sealed and heat-insulating state inside the shell 2 and preventing a large influx of cold air from the outside, further consolidating the temperature buffering effect.
[0027] Furthermore, such as Figure 2 and Figure 3 As shown, the bottom of the heat-insulating flap 6 is provided with a counterweight limiting rod 8. The left and right ends of the counterweight limiting rod 8 extend beyond the output end of the shell 2 and form abutment interference with the shell 2. The counterweight limiting rod 8 at the bottom of the heat-insulating flap 6 ensures, on the one hand, that the flap can quickly and accurately reset when there is no external force pushing it up from the graphite crucible, thus ensuring the continuity of the heat-insulating effect; on the other hand, the abutment between the counterweight limiting rod 8 and the shell 2 can limit the swing angle of the flap, preventing the flap from flipping into the shell 2 and colliding with the next graphite crucible due to excessive swing amplitude.
[0028] Furthermore, such as Figure 2 and Figure 3 As shown, the sand hopper 3 is provided in two sets. A storage bin 9 is provided above the sand hopper 3. The bottom of the storage bin 9 is connected to the sand hopper 3. A spiral stirring shaft 11 driven to rotate by a drive motor 10 is also provided inside the sand hopper 3. The spiral stirring shaft 11 is located above the sand outlet 4. The sand outlet 4 has a tubular structure. An opening flap 12 is provided inside the sand outlet 4. The opening flap 12 is connected to an opening motor 13 by a transmission shaft.
[0029] Two sets of sand hoppers 3 work in conjunction with the upper storage bin 9. The storage bin 9 is replenished with sand from the outside via an elevator, achieving a continuous supply of sand and avoiding the problem of interruption in the supply of a single sand hopper 3, thus improving the continuous operation capability of the device. The spiral stirring shaft 11 inside the sand hopper 3 rotates under the drive of the drive motor 10, which can effectively prevent sand from getting stuck or clumping, ensuring that the sand outlet 4 is unobstructed. The tubular structure of the sand outlet 4, together with the opening flap 12 and the opening motor 13, can precisely control the amount of sand injected, avoiding excessive sand waste and overflow that could contaminate the track.
[0030] Furthermore, such as Figure 2 As shown, the housing 2 is provided with inspection windows 14, which are respectively provided on the left and right side walls of the housing 2. The inspection windows 14 facilitate the adjustment and maintenance of the equipment, reduce production downtime caused by malfunctions, improve the reliability and maintenance efficiency of the equipment, and ensure the continuity of production.
Claims
1. A graphite crucible firing tunnel kiln discharge protection device, which is connected at the discharge port of the tunnel kiln and covers above the conveying track (1) of the tunnel kiln, characterized in that: The system includes a shell (2) and a sand hopper (3) above the shell (2). The sand hopper (3) is funnel-shaped and has a sand outlet (4). The graphite crucible passes below the sand outlet (4) via a conveying track (1). The sand hopper (3) injects sand into the graphite crucible. The sand hopper (3) is also equipped with a heating tube (5). The input end of the shell (2) is connected to the kiln outlet of the tunnel kiln. The output end of the shell (2) is equipped with a heat-insulating flap (6).
2. The graphite crucible firing tunnel kiln discharge protection device according to claim 1, characterized in that: The heat-insulating flap (6) is hinged to the shell (2) by means of the hinge shaft (7). The plane of the hinge shaft (7) of the heat-insulating flap (6) is higher than the plane of the upper edge of the graphite crucible. The heat-insulating flap (6) is lifted by the movement of the graphite crucible and swings around the hinge shaft (7).
3. The graphite crucible firing tunnel kiln discharge protection device according to claim 2, characterized in that: The bottom of the heat-insulating flap (6) is provided with a counterweight limiting rod (8), and the left and right ends of the counterweight limiting rod (8) extend outside the output end of the shell (2) and form abutment interference with the shell (2).
4. The graphite crucible firing tunnel kiln discharge protection device according to claim 1, characterized in that: The sand hopper (3) is provided in two sets. A storage bin (9) is provided above the sand hopper (3). The bottom of the storage bin (9) is connected to the sand hopper (3). A spiral stirring shaft (11) driven to rotate by a drive motor (10) is also provided inside the sand hopper (3). The spiral stirring shaft (11) is located above the sand outlet (4). The sand outlet (4) has a tubular structure. An opening flap (12) is provided inside the sand outlet (4). The opening flap (12) is connected to an opening motor (13) by a transmission shaft.
5. The graphite crucible firing tunnel kiln discharge protection device according to claim 1, characterized in that: The housing (2) is provided with inspection windows (14), which are respectively provided on the left and right side walls of the housing (2).