Diamond grain curing and sintering furnace

Abstract

The invention discloses a diamond grain curing and sintering furnace, which relates to the technical field of metal powder processing and manufacturing, and comprises a base box body, a left bell jar, a right bell jar, an inner bell jar, a variable-pitch spiral heating wire, a heat exchange chamber, a liquid storage cylinder and a piston, a double-station structure is adopted, and the variable-pitch design of the heating wire is matched with convection to realize uniform heating of the temperature in a cavity; through a liquid storage cylinder, a piston and a heat exchange chamber, rapid heat exchange cooling is conducted through a heat conduction agent, and an atmosphere protection system (comprising a gas cylinder, an observation bottle and a sensor), an automatic bell jar lifting and rotating mechanism, an automatic piston lifting mechanism, a temperature sensor and the like are further arranged. The device has the beneficial effects of uniform heating temperature, accurate and controllable atmosphere, rapid cooling, high automation degree, safety, reliability, energy conservation and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of metal powder processing and manufacturing, and specifically to a diamond grain curing and sintering furnace. Background Art

[0002] The curing and sintering of diamond grains is a key link in their manufacturing process, which requires high temperature, a specific atmosphere (such as hydrogen or inert gas), and precise temperature and cooling control to obtain high-performance products. Traditional sintering furnaces often have limitations in temperature uniformity, atmosphere control, cooling efficiency, or automation level, and are difficult to meet the requirements of modern industry for high-quality and high-efficiency batch production of diamond grains.

[0003] The specification of Chinese invention patent CN118123022B discloses a powder metallurgy sintering furnace with IPC classification number B22F. This furnace mainly improves the heating efficiency of the powder by setting an air duct with air outlet holes inside the furnace body, arranging heating elements in the air duct, and regulating the outflow of gas (possibly air) through a control element. This design focuses on heating the powder through hot air circulation and may be beneficial for some conventional powder metallurgy.

[0004] The specification of Chinese invention patent CN110763010B discloses a sintering furnace with heating uniformity and heat recovery function with IPC classification number B22F. This furnace uses a conveyor belt to transport workpieces and evenly spreads the workpieces through a feeding mechanism, improving the uniformity of space heating. The furnace also has a recovery mechanism that recovers part of the heat from the workpieces through devices such as a heat absorption box and heat conduction pipelines and stores it in a heat storage box, realizing the recovery and utilization of heat and improving the energy-saving performance.

[0005] Although the above designs have improvements in heating efficiency, uniformity, or heat recovery, they still have deficiencies for materials such as diamond grains that require strict sintering atmosphere, efficient batch production, and precise cooling control. For example, existing technologies usually lack precise and controllable means of specific atmosphere protection and their safety monitoring (such as concentration monitoring and safety replacement in a hydrogen atmosphere); it is difficult to achieve rapid, efficient, and controllable cooling, which affects the sintering cycle and product performance; and when loading materials in multiple layers (such as diamond grains are usually placed on multiple trays), it is difficult to ensure ideal temperature uniformity by relying on hot air circulation or simple spreading, and the automation level is not high, restricting production efficiency and sintering quality. Therefore, there is an urgent need for a sintering furnace that can meet the requirements of high-efficiency, high-quality, automated, and safe sintering of diamond grains. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and propose a diamond grain curing and sintering furnace to solve the above problems.

[0007] The object of the present invention is achieved by the following technical solutions: A diamond particle solidification and sintering furnace, comprising two controllers electrically connected to each other and a base box body. At the top of the base box body, there are a left bell jar and a right bell jar symmetrically arranged left and right. Inside the left bell jar and the right bell jar, there are inner bell jars fixedly connected. Inside the two inner bell jars, there are heating wire brackets clamped. On the heating wire brackets, there are multiple heating wire fixing blocks clamped. Between the heating wire brackets, there are a bottom heating wire, a middle heating wire, and a top heating wire. Between the inner walls of the left bell jar and the right bell jar and the outer walls of the corresponding inner bell jars, there are heat exchange chambers. Inside the base box body, at the position between the left bell jar and the right bell jar, there is a liquid storage cylinder fixedly connected. The bottom ends of the two heat exchange chambers are both connected to the top end of the liquid storage cylinder through pipelines, and the top ends of the two heat exchange chambers are both connected to the bottom end of the liquid storage cylinder through pipelines. Inside the liquid storage cylinder, there is a piston slidably connected. At the positions on the top of the base box body corresponding to the left bell jar and the right bell jar, there are tray brackets rotatably connected. Inside the base box body, at the positions corresponding to the two tray brackets, there are rotary motors fixedly connected. The bottom heating wire, the middle heating wire, and the top heating wire are all arranged in a variable pitch spiral, and the pitches of the bottom heating wire, the middle heating wire, and the top heating wire itself gradually increase from bottom to top. The pitch at the bottom end of the top heating wire is greater than the pitch at the top end of the middle heating wire, and the pitch at the bottom end of the middle heating wire is greater than the pitch at the top end of the bottom heating wire.

[0008] The bottom heating wire, the middle heating wire, and the top heating wire are all fixedly connected to the heating wire brackets through the heating wire fixing blocks. On the pipelines connected to the top ends and the bottom ends of the two heat exchange chambers, there are solenoid valves installed. At the bottom ends of the left bell jar and the inner bell jar and the right bell jar and the inner bell jar, there are sealing rings fixedly connected. At the bottom ends of the two sealing rings, there are sealing gaskets fixedly connected, and the sealing gaskets are abutted against the top of the base box body.

[0009] The power shaft of the rotary motor is fixedly connected to the tray bracket. Outside the tray bracket, there are multiple trays for placing diamond particles sleeved. Between adjacent two trays, there are spacer rings. Inside the base box body, there is a gas cylinder fixedly connected. The exhaust ports of the gas cylinder are respectively connected to the inner walls near the top ends of the inner bell jars through pipelines. On the pipelines between the gas cylinder and the inner bell jar and between the observation bottle and the inner bell jar, there are solenoid valves installed.

[0010] At the position between the left bell jar and the right bell jar on the top of the base box body, there is an observation bottle fixedly connected. The inner walls near the bottom ends of the two inner bell jars are both connected to the inner wall near the bottom end of the observation bottle through pipelines. The gas cylinder is filled with hydrogen.

[0011] The bottom heating wire, the middle heating wire, and the top heating wire are all electrically connected to the controller through wires. At the positions on the inner walls of the inner bell jars corresponding to the bottom heating wire, the middle heating wire, and the top heating wire, there are temperature sensors fixedly connected. At the bottom end of the piston, there is a piston screw sleeve fixedly connected, and inside the piston screw sleeve, there is a piston lifting screw threadedly connected.

[0012] A plurality of bolts are fixedly connected to the top end of the sealing ring. The plurality of bolts all penetrate upward through the corresponding left bell jar and right bell jar, and nuts are threadedly connected to the penetrated parts. The left bell jar and the right bell jar are respectively fixedly connected to the base box body through the right bell jar and a quick-release mechanism.

[0013] Lifting screw sleeves are fixedly connected to the top ends of the left bell jar and the right bell jar through brackets. Cam columns are fixedly connected to the bottom ends of the lifting screw sleeves. Bell jar lifting screw rods are threadedly connected inside the cam columns. Piston lifting screw rods and the bottom ends of the two bell jar lifting screw rods are fixedly connected with reduction motors. The plurality of reduction motors are all electrically connected to the controller. Guide grooves are formed in the outer ends of the lifting screw sleeves along the axial direction thereof. The guide grooves and the spiral grooves are both slidably connected to the base box body.

[0014] Spiral grooves are formed in the outer ends of the cam columns. The spiral grooves are slidably connected to the base box body.

[0015] Hydrogen is filled in the gas cylinder, and water is filled in the observation bottle. A hydrogen concentration sensor is fixedly connected to the top end of the observation bottle. The hydrogen concentration sensor is electrically connected to the controller. Observation windows are opened on the left bell jar, the right bell jar and the inner bell jar.

[0016] A distribution box is fixedly connected inside the base box body. The space in the liquid storage cylinder above the piston is filled with a heat-conducting agent. The heat-conducting agent is lead-bismuth alloy or molten salt. The volume of the liquid storage cylinder is equal to the volume of the heat exchange chamber.

[0017] The beneficial effects of the present invention are as follows: Adopting a double-station design, when sintering and cooling are carried out in one working cavity, the other working cavity can synchronously carry out loading, preparing for atmosphere replacement, and even preheating using waste heat. With the functions of automatic loading and unloading and rapid cooling, the two stations can achieve efficient continuous production alternately without interruption, significantly improving the overall production capacity and utilization rate of the equipment.

[0018] The variable-pitch spiral heating wire design can form a heat gradient from bottom to top in the cavity, generating natural heat convection to promote the temperature uniformity in the cavity. In addition, by rotating the tray bracket, the diamond grains on the multi-layer trays are heated in all directions during the sintering process, further improving the temperature uniformity of the sintering and ensuring the consistency and high quality of the products.

[0019] The gas protection system can conveniently and safely introduce and maintain a specific process atmosphere (such as hydrogen) into the cavity. Through the observation bottle and the gas concentration sensor, the gas replacement process and the atmosphere state in the cavity can be monitored in real time, ensuring that the sintering is carried out under precisely controlled atmosphere conditions, meeting the process requirements of different materials, and effectively preventing oxidation.

[0020] The heat exchange cavity exchanges heat with a high thermal conductivity medium (such as lead-bismuth alloy or molten salt) for cooling. By automatically controlling the lifting of the piston, the heat-conducting agent can be quickly pushed into the heat exchange cavity to absorb heat, achieving rapid cooling and significantly shortening the sintering cycle.

[0021] Automatic lifting, rotation and locking, as well as the automatic drive of the piston, reduce manual intervention, lower the operating labor intensity, improve the stability and safety of equipment operation. The quick-release mechanism and the bolt-nut fixing structure further simplify the sealing and fixing process of the bell jar.

[0022] The present invention can utilize the heat absorbed and carried by the heat-conducting agent in one working cavity during the cooling process to preheat another working cavity to be sintered. This way of waste heat recovery and reuse effectively reduces the energy consumption of the entire sintering process.

[0023] By observing the bottle to visualize the gas replacement process and combining with the real-time monitoring of the hydrogen concentration sensor, it ensures that the hydrogen concentration in the cavity reaches the safe range. The tight sealing structure prevents gas leakage, and the automatic operation reduces the contact between personnel and high temperature and potentially dangerous gases.

[0024] Multiple temperature sensors are distributed in the cavity to monitor the temperature change in real time and feed the data back to the controller. The controller accurately adjusts the power of the heating wire and the movement of the automatic mechanism according to the preset program and the sensor signals, realizing the closed-loop control of key process parameters such as the sintering temperature curve, atmosphere, and cooling rate, ensuring the accuracy and repeatability of the process.

[0025] Two controllers electrically connected to each other provide a backup function. Even if one of the controllers fails, the other can take over the control task to ensure that the equipment can continue to operate, improving the overall reliability of the equipment.

[0026] Observation windows are provided on the bell jar and the inner bell jar, allowing operators to directly observe the diamond grains or the process state inside the cavity during the operation of the equipment, facilitating the timely discovery of problems and adjustments. Brief Description of the Drawings

[0027] Figure 1 is the overall structure diagram of the present invention; Figure 2 is the overall exploded view of the present invention; Figure 3 is the partial explosion of the present invention Figure 1 ; Figure 4 is the partial explosion of the present invention Figure 2 ; Figure 5 is the partial explosion of the present invention Figure 3 ; Figure 6 Local explosion of the present invention Figure 4 ; Figure 7 Local explosion of the present invention Figure 5 ; Figure 8 Front view of the present invention; Figure 9 Of the present invention Figure 8 Cross-sectional view taken along line A-A; Figure 10 Of the present invention Figure 9 Cross-sectional view taken along line B-B; Figure 11 Of the present invention Figure 10 Cross-sectional view taken along line C-C; Figure 12 External structure diagram of the present invention.

[0028] Description of reference numerals in the figure 1. Base box body; 2. Left bell jar; 3. Right bell jar; 4. Inner bell jar; 5. Heating wire support; 6. Heating wire fixing block; 7. Bottom heating wire; 8. Middle heating wire; 9. Top heating wire; 10. Heat exchange chamber; 11. Liquid storage cylinder; 12. Sealing ring; 13. Piston; 14. Piston lifting screw rod; 15. Tray support; 16. Gas cylinder; 17. Observation bottle; 18. Lifting screw sleeve; 19. Cam column; 20. Bell jar lifting screw rod. Detailed implementation manners

[0029] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0030] It should be noted that the orientation concepts of "left", "right", "up", "down", "front", "back", "inner", and "outer" in the following solutions are all relative directions, and will not be listed one by one here.

[0031] Embodiment 1: As Figures 1 to 12 shown, this embodiment discloses a diamond and diamond particle curing and sintering furnace, and its main structure and functions are reflected in the dual-station design, variable-pitch spiral heating wire heating method, and the basic cooling system based on the heat exchange cavity and heat-conducting agent.

[0032] The diamond and diamond particle curing and sintering furnace of this embodiment includes two controllers electrically connected to each other and a base box body 1. The top end of the base box body 1 is symmetrically provided with a left bell jar 2 and a right bell jar 3, forming two independent working areas.

[0033] Inside the left bell jar 2 and the right bell jar 3, an inner bell jar 4 is fixedly connected. The inner bell jar 4 is the cavity where sintering actually takes place. Inside both inner bell jars 4, a heating wire bracket 5 is clamped. Multiple heating wire fixing blocks 6 are clamped on the heating wire bracket 5 for supporting and fixing the heating wires.

[0034] A bottom heating wire 7, a middle heating wire 8, and a top heating wire 9 are arranged between the heating wire brackets 5. These heating wires are fixedly connected to the heating wire brackets 5 through the heating wire fixing blocks 6. The unique feature is that the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 are all arranged in a variable pitch helix. Specifically, their own pitches gradually increase from bottom to top. This variable pitch setting enables different heat distributions to be generated by the heating wires at different heights. The bottom heating wire 7 generates the most heat, the middle heating wire 8 generates the second most heat, and the top heating wire 9 generates the least heat. At the same time, in order to ensure the continuity of the heat gradient, the pitch at the bottom end of the top heating wire 9 is greater than the pitch at the top end of the middle heating wire 8, and the pitch at the bottom end of the middle heating wire 8 is greater than the pitch at the top end of the bottom heating wire 7.

[0035] A heat exchange chamber 10 is provided between the inner walls of the left bell jar 2 and the right bell jar 3 and the outer walls of the corresponding inner bell jars 4. This heat exchange chamber 10 is a channel for rapid cooling. A liquid storage cylinder 11 is fixedly connected at a position inside the base box body 1 between the left bell jar 2 and the right bell jar 3.

[0036] The bottom ends of the two heat exchange chambers 10 are both connected to the top end of the liquid storage cylinder 11 through pipes, while the top ends of the two heat exchange chambers 10 are connected to the bottom end of the liquid storage cylinder 11 through pipes. Electromagnetic valves are installed on the pipes connected to the top and bottom ends of the two heat exchange chambers 10 to control the inlet and outlet of the heat transfer agent. A piston 13 is slidably connected inside the liquid storage cylinder 11.

[0037] At positions corresponding to the left bell jar 2 and the right bell jar 3 at the top end of the base box body 1, tray brackets 15 are rotatably connected. At positions corresponding to the two tray brackets 15 inside the base box body 1, rotating motors are fixedly connected for driving the tray brackets 15 to rotate.

[0038] Sealing rings 12 are fixedly connected to the bottom ends of the left bell jar 2 and the inner bell jar 4 and the right bell jar 3 and the inner bell jar 4. Sealing rings are fixedly connected to the bottom ends of the two sealing rings 12. These sealing rings are abutted against the top end of the base box body 1 for forming a sealed cavity when the bell jars descend.

[0039] A distribution box is fixedly connected inside the base box body 1 to provide power control and distribution for the entire device. The space above the piston 13 inside the liquid storage cylinder 11 is filled with a heat transfer agent. The heat transfer agent can be a high thermal conductivity medium such as lead-bismuth alloy or molten salt. The volume of the liquid storage cylinder 11 is designed to be equal to the volume of the heat exchange chamber 10 to ensure that the heat transfer agent can completely fill the heat exchange chamber 10 to achieve effective heat exchange.

[0040] Working process: First, place the diamond grains to be sintered on the tray (the tray is placed on the tray support 15), select a working station (such as the left bell jar 2), move the left bell jar 2 downward until the sealing ring at the bottom of the sealing ring 12 connected to it is in close contact with the top of the base box body 1, forming a sealed cavity. Then, firmly fix the left bell jar 2 to the base box body 1 to ensure good sealing of the cavity.

[0041] Independently control the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 to start heating through the controller. Since the heating wires are arranged in a variable pitch helix and the pitch gradually increases from bottom to top, and due to the pitch relationship between the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9, the heat generated by the bottom heating wire 7 is the largest, and the heat gradually decreases from bottom to top. This heat distribution causes the gas inside the inner bell jar 4 to be unevenly heated, generating a thermal convection from bottom to top. This convection helps the temperature distribution inside the inner bell jar 4 to be more uniform, so that the diamond grains placed on multiple trays can be uniformly heated for sintering.

[0042] When the diamond grains inside the left bell jar 2 are sintered and enter the cooling stage, through a certain mechanism (in this basic embodiment, it may require an external drive piston 13 or simple control through the controller), move the piston 13 in the liquid storage cylinder 11 upward. The upward movement of the piston 13 pushes the heat-conducting agent located at the top of the piston 13 in the liquid storage cylinder 11 into the heat exchange chamber 10 corresponding to the left bell jar 2 through the pipeline. During this process, it may be necessary to open the solenoid valve connecting the top of the liquid storage cylinder 11 to the bottom of the heat exchange chamber 10 and open another solenoid valve connecting the bottom of the liquid storage cylinder 11 to the top of the heat exchange chamber 10 (or reverse operation depending on the specific flow path design). The heat-conducting agent flows in the heat exchange chamber 10 and absorbs the heat of the inner bell jar 4, so that the temperature inside the inner bell jar 4 drops rapidly, realizing rapid cooling.

[0043] After the cooling is completed, move the piston 13 downward. By controlling the corresponding solenoid valve to open, the suction force generated by the downward movement of the piston 13 sucks the high-temperature heat-conducting agent in the heat exchange chamber 10 back into the liquid storage cylinder 11 through the pipeline.

[0044] After the cooling is completed, release the fixation of the left bell jar 2 to the base box body 1, move the left bell jar 2 upward, open the cavity, and take out the sintered diamond grains.

[0045] During the sintering and cooling process of the left bell jar 2, another station (the right bell jar 3) can be used to prepare the next batch of sintering, or used as an independent single-sintering station. Two controllers electrically connected to each other can achieve the basic control of the two stations and provide a backup function.

[0046] Adopting a symmetrical design with a double-bellows, including a left bellows 2 and a right bellows 3, to form a two-station layout. When sintering or cooling is carried out at one station, loading or unloading can be performed at the other station, thereby improving the continuous working ability of the equipment and the overall production efficiency.

[0047] The variable-pitch spiral arrangement of the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 and their pitch relationship can form a heat gradient from bottom to top, triggering the up-and-down convection of the gas inside the inner bellows 4, effectively improving the temperature uniformity inside the inner bellows 4, enabling the diamond grits placed on multiple trays to obtain a more uniform sintering effect.

[0048] A heat exchange system composed of a heat exchange chamber 10, a liquid storage cylinder 11, a piston 13, and a heat-conducting agent (such as lead-bismuth alloy or molten salt) can rapidly and controllably cool the inner bellows 4 after sintering is completed, shortening the sintering cycle and improving the production efficiency.

[0049] Integrating the liquid storage cylinder 11 and related pipelines and solenoid valves inside the base box 1 results in a compact structure and a small footprint.

[0050] Although this embodiment emphasizes the basic functions, the lifting mechanism of the piston 13 and the solenoid valves on the pipelines of the heat exchange chamber 10 have laid the foundation for the subsequent realization of automated control of the cooling process.

[0051] Two controllers that are electrically connected to each other provide a backup function. When one controller fails, the other can take over the control task, improving the operating reliability of the equipment.

[0052] Embodiment 2: As Figures 1 to 12 shown, on the basis of the basic structure of Embodiment 1, this embodiment further adds functions such as automated loading and unloading, atmosphere-protected sintering, precise process control, and safety monitoring, providing a more efficient, stable, and safe sintering solution.

[0053] The diamond grain curing and sintering furnace of this embodiment includes two controllers that are electrically connected to each other and a base box body 1. At the top of the base box body 1, there are a left bell jar 2 and a right bell jar 3. An inner bell jar 4 is fixedly connected inside the left bell jar 2 and the right bell jar 3. A heating wire support 5 is clamped inside the inner bell jar 4. A plurality of heating wire fixing blocks 6 are clamped on the heating wire support 5. Between the heating wire supports 5, there are a bottom heating wire 7, a middle heating wire 8, and a top heating wire 9. They are all fixedly connected to the heating wire support 5 through the heating wire fixing blocks 6 and are arranged in a variable pitch helix, with the pitch gradually increasing from bottom to top, and the pitch relationship between each section conforms to the description of claim 1. The bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 are all electrically connected to the controller through wires to achieve precise independent control. Temperature sensors are fixedly connected to the positions on the inner wall of the inner bell jar 4 corresponding to the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 for real-time monitoring of the temperature at different positions.

[0054] There is a heat exchange chamber 10 formed between the inner walls of the left bell jar 2 and the right bell jar 3 and the outer wall of the corresponding inner bell jar 4. Inside the base box body 1, a liquid storage cylinder 11 is fixedly connected between the left bell jar 2 and the right bell jar 3. The bottom ends of the two heat exchange chambers 10 are connected to the top end of the liquid storage cylinder 11 through pipes, and the top ends are connected to the bottom end of the liquid storage cylinder 11 through pipes. Solenoid valves are installed on the pipes. A piston 13 is slidably connected inside the liquid storage cylinder 11. The space in the liquid storage cylinder 11 above the piston 13 is filled with a heat conducting agent, and the heat conducting agent is lead-bismuth alloy or molten salt. The volume of the liquid storage cylinder 11 is equal to the volume of the heat exchange chamber 10. Different from Embodiment 1, the bottom end of the piston 13 is fixedly connected with a piston screw sleeve, and a piston lifting screw 14 is threadedly connected inside the piston screw sleeve. The bottom end of the piston lifting screw 14 is fixedly connected with a reduction motor, and this reduction motor is electrically connected to the controller, thus realizing the automatic control of the lifting of the piston 13.

[0055] At the positions on the top of the base box body 1 corresponding to the left bell jar 2 and the right bell jar 3, there are tray supports 15 rotatably connected. At the positions inside the base box body 1 corresponding to the two tray supports 15, there are rotation motors fixedly connected. The power shafts of the rotation motors are fixedly connected to the tray supports 15 to drive the tray supports 15 to rotate. A plurality of trays for placing diamond grains are sleeved on the outer ends of the tray supports 15. There is a spacer ring between adjacent two trays for separating and supporting multiple layers of trays.

[0056] Inside the base box body 1, a gas cylinder 16 is fixedly connected. Hydrogen (or other gases required by the process) is filled in the gas cylinder 16. The exhaust ports of the gas cylinder 16 are respectively connected to the inner wall near the top end of the inner bell jar 4 through pipelines, serving as the inlet of the atmosphere protection gas. At the position between the left bell jar 2 and the right bell jar 3 at the top end of the base box body 1, an observation bottle 17 is fixedly connected. The inner walls near the bottom ends of the two inner bell jars 4 are both connected to the inner wall near the bottom end of the observation bottle 17 through pipelines, serving as the channels for gas discharge and observation. Solenoid valves are installed on the pipelines between the gas cylinder 16 and the inner bell jar 4 and between the observation bottle 17 and the inner bell jar 4, for precisely controlling the on-off and flow direction of the gas. Water is filled in the observation bottle 17, for observing the state of gas flow through bubbles. A hydrogen concentration sensor is fixedly connected to the top end of the observation bottle 17. The hydrogen concentration sensor is electrically connected to the controller, for real-time monitoring of the hydrogen concentration in the discharged gas, ensuring that the atmosphere in the cavity meets the requirements and is safe.

[0057] Sealing rings 12 are fixedly connected to the bottom ends of the left bell jar 2, the inner bell jar 4, and the right bell jar 3, and the top ends of the sealing rings 12 are fixedly connected with multiple bolts. The bolts penetrate upwards through the corresponding left bell jar 2 and right bell jar 3, and the penetrated parts are threadedly connected with nuts. More reliable sealed connection is achieved through the fastening of the bolts and nuts. The bottom ends of the sealing rings 12 are fixedly connected with sealing rings, and the sealing rings are abutted against the top end of the base box body 1 to form a cavity seal. In order to achieve rapid automated loading and unloading, the left bell jar 2 and the right bell jar 3 are respectively fixedly connected to the base box body 1 through quick-release mechanisms, replacing the possible manual fixing method in Embodiment 1.

[0058] Lifting screw sleeves 18 are fixedly connected to the top ends of the left bell jar 2 and the right bell jar 3 through brackets. Cam columns 19 are fixedly connected to the bottom ends of the lifting screw sleeves 18. Bell jar lifting screw rods 20 are threadedly connected inside the cam columns 19. The bottom ends of the two bell jar lifting screw rods 20 are fixedly connected with reduction motors. These reduction motors are electrically connected to the controller, for driving the automated lifting of the bell jar assembly (the combination of the left bell jar 2 or the right bell jar 3 and the inner bell jar 4). Guide grooves are opened along the axial direction at the outer ends of the lifting screw sleeves 18, and spiral grooves are opened at the outer ends of the cam columns 19. The guide grooves and the spiral grooves are both slidably connected to the corresponding matching structures of the base box body 1. When the bell jar lifting screw rod 20 drives the cam column 19 to lift or lower, due to the cooperation between the spiral groove of the cam column 19 and the base box body 1, under the guidance of the guide groove, the bell jar assembly rotates around the bell jar lifting screw rod 20 while lifting or lowering, realizing the automatic opening and closing actions of the bell jar.

[0059] Observation windows are opened on the left bell jar 2, the right bell jar 3, and the inner bell jar 4, facilitating the operator to directly observe the situation inside the cavity.

[0060] Working process: This embodiment makes full use of the dual-station, automation, and atmosphere control functions, enabling alternating and uninterrupted sintering of two stations and preheating using waste heat.

[0061] At the right bell jar 3 station (assuming the left bell jar 2 is working), the operator places the diamond grits to be sintered on multiple trays and stacks them on the tray support 15 through spacer rings. After preparation, the controller controls the reduction motor corresponding to the right bell jar 3 to drive the bell jar lifting screw 20 to rotate. The bell jar lifting screw 20 drives the cam column 19 to descend. During the descent, the spiral groove of the cam column 19 cooperates with the base box body 1, and under the guidance of the guide groove of the lifting screw sleeve 18, the right bell jar 3 assembly rotates and moves towards the working area of the base box body 1, finally descending in place. The sealing ring contacts the top of the base box body 1. The controller further controls the quick-release mechanism to firmly fix the right bell jar 3 to the base box body 1, and provides additional sealing pressure through the bolts and nuts at the top of the sealing ring 12 to complete the cavity sealing.

[0062] After sealing is completed, the controller opens the solenoid valve connecting the gas cylinder 16 to the top air inlet of the inner bell jar 4 corresponding to the right bell jar 3, and at the same time opens the solenoid valve connecting the bottom of the inner bell jar 4 corresponding to the right bell jar 3 to the observation bottle 17. Hydrogen in the gas cylinder 16 is introduced from the top of the inner bell jar 4, squeezing out the original gas (such as air) in the cavity downward. The discharged gas passes through the observation bottle 17. Bubbles will be generated when the gas passes through the water in the observation bottle 17. The operator can observe the bubbles through the observation window to judge whether the gas is being discharged. The hydrogen concentration sensor continuously detects the hydrogen concentration in the discharged gas. When the controller receives the signal from the hydrogen concentration sensor and judges that the hydrogen concentration in the cavity reaches the set safety threshold, it is considered that most of the original gas in the cavity has been replaced by hydrogen. The controller closes the corresponding solenoid valves to complete the atmosphere replacement.

[0063] If the left bell jar 2 has just completed sintering and entered the cooling stage, there may be high-temperature heat transfer medium in its heat exchange chamber 10. At this time, the controller can control the piston lifting screw 14 on the left side to drive the piston 13 to move downward, sucking back the heat transfer medium into the liquid storage cylinder 11. Then, the controller can control the piston lifting screw 14 on the right side to drive the piston 13 to move upward, pushing the high-temperature heat transfer medium in the liquid storage cylinder 11 into the heat exchange chamber 10 corresponding to the right bell jar 3 through the pipeline (by controlling the corresponding solenoid valves). The heat transfer medium transfers heat to the inner bell jar 4 to preheat the diamond grits inside. After preheating is completed, the controller controls the piston 13 to move downward again to suck back the heat transfer medium into the liquid storage cylinder 11. This way realizes the recycling of heat.

[0064] After preheating (if any) or atmosphere replacement is completed, the controller independently controls the heating powers of the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 according to the set sintering program. The temperature sensors continuously feedback the temperature changes at different positions inside the inner bell jar 4. The controller precisely adjusts the heating wire powers based on the feedback signals to achieve precise temperature control. At the same time, the controller drives the rotation motor to rotate the tray support 15, driving the diamond grits on the tray to slowly rotate, further ensuring uniform heating. Under a hydrogen atmosphere, the diamond grits are solidified and sintered.

[0065] After sintering is completed, the controller controls the piston lifting screw 14 corresponding to the right bell jar 3 to drive the piston 13 to move upward. The controller controls the corresponding solenoid valve to open, pushing the heat transfer agent in the liquid storage cylinder 11 into the heat exchange chamber 10 corresponding to the right bell jar 3. The heat transfer agent absorbs the heat of the inner bell jar 4, rapidly cooling the cavity to a safe temperature.

[0066] After cooling is completed, the controller controls the piston lifting screw 14 to move downward, sucking the heat transfer agent in the heat exchange chamber 10 back into the liquid storage cylinder 11. At the same time, the controller slowly opens the exhaust valve leading to the outside (not specifically numbered but mentioned in the working principle for exhausting hydrogen), slowly and safely exhausting the hydrogen inside the inner bell jar 4 (or recovering it to a specific device). The hydrogen concentration sensor continues to monitor during this process to ensure safety.

[0067] After exhausting, the controller controls the quick-release mechanism corresponding to the right bell jar 3 to release the fixation. Then, the controller controls the reduction motor to drive the bell jar lifting screw 20 to rotate, driving the cam column 19 to rise. During the rising process, due to the cooperation between the spiral groove of the cam column 19 and the base box body 1, under the guidance of the guide groove, the right bell jar 3 assembly rotates and opens away from the working area of the base box body 1. When the bell jar rises and rotates into place, the operator can conveniently take out the sintered diamond grits and load new materials to be sintered, preparing for the next cycle.

[0068] While the above sintering process is carried out in the right bell jar 3, the left bell jar 2 can be loaded, have its atmosphere replaced, or have completed sintering and entered the cooling stage, or be in the process of unloading, realizing the alternation and continuous operation of the two workstations. Two mutually electrically connected controllers work together to control the entire automated process and provide backup.

[0069] The automated bell jar lifting and rotating mechanism composed of the bell jar lifting screw sleeve 18, the cam column 19, the bell jar lifting screw 20, and the reduction motor, as well as the automated piston driving mechanism composed of the piston lifting screw 14 and its reduction motor, cooperate with the quick-release mechanism, greatly reducing manual operation and improving the loading and unloading efficiency and the automation level of the equipment.

[0070] A system consisting of a gas cylinder 16, a gas pipeline, a solenoid valve, an observation bottle 17, a hydrogen concentration sensor, etc. enables the convenient and safe replacement and maintenance of a specific atmosphere (such as hydrogen) inside the cavity, meeting the special requirements of materials such as diamond grains for the sintering atmosphere, and improving the sintering quality and scope of application.

[0071] The bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 are electrically connected to the controller through wires. Cooperating with the temperature sensors on the inner wall of the inner bell jar 4, it realizes real-time monitoring and precise control of the temperature in multiple regions with high precision, ensuring the accurate execution of the sintering temperature curve.

[0072] During use, place the diamond grains to be sintered on the tray. Then move the left bell jar 2 or the right bell jar 3 downward until the sealing ring at the bottom end of the sealing ring 12 connected to it contacts the top end of the base box body 1. Then firmly fix the left bell jar 2 or the right bell jar 3 to the base box body 1. Then open the solenoid valve connected to the gas cylinder 16, and introduce the gas in the gas cylinder 16 into the inner bell jar 4 from the top end of the inner bell jar 4. During this process, the gas in the inner bell jar 4 is squeezed out of the observation bottle 17 by hydrogen. At this time, the gas passes through the observation bottle 17, and the operator can judge whether hydrogen enters the inner bell jar 4 by observing whether there is gas passing through the observation bottle 17. At the same time, the hydrogen content in the gas is detected by the hydrogen concentration sensor. When the hydrogen content in the gas reaches the threshold value, it is judged that most of the gas in the inner bell jar 4 has been replaced by hydrogen. Then close the corresponding solenoid valve to start sintering. During sintering, the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 are independently controlled by the controller to generate heat. Since the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 are all arranged in a variable pitch spiral, and the pitch of the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 itself gradually increases from bottom to top. The pitch at the bottom end of the top heating wire 9 is greater than the pitch at the top end of the middle heating wire 8, and the pitch at the bottom end of the middle heating wire 8 is greater than the pitch at the top end of the bottom heating wire 7. Therefore, the heat generated by the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 gradually decreases. That is, the bottom heating wire 7 at the bottom end generates the most heat. Since the bottom heating wire 7 generates the most heat, it further causes the gas at the bottom end of the inner bell jar 4 to be heated more, causing the gas to generate up and down convection in the inner bell jar 4. Thus, the diamond grains on multiple trays can be evenly heated. At the same time, through multiple temperature sensors, the temperature changes at different positions in the inner bell jar 4 are detected in real time. Then, the heat generation of the bottom heating wire 7, the middle heating wire 8, and the top heating wire 9 is controlled through the temperature changes, so that the diamond grains can be better sintered. When the diamond grains sintered in the left bell jar 2 enter the cooling stage, rotate the piston lifting screw 14 to move the piston 13 upward, so that the heat transfer agent in the liquid storage cylinder 11 enters the heat exchange chamber 10 that needs to be cooled. The heat transfer agent absorbs the heat of the inner bell jar 4 in the heat exchange chamber 10, thereby reducing the temperature in the inner bell jar 4. After the cooling is completed, move the piston 13 downward to suck the heat transfer agent in the corresponding heat exchange chamber 10 into the liquid storage cylinder 11; at the same time, slowly discharge the hydrogen in the inner bell jar 4 corresponding to the left bell jar 2, and then the left bell jar 2 can be opened upward to take out the sintered diamond grains; When it is necessary to move the left bell jar 2 or the right bell jar 3 upward or downward, rotate the corresponding bell jar lifting screw 20. The bell jar lifting screw 20 drives the corresponding cam post 19 to move upward or downward. When the cam post 19 moves upward to contact the base box body 1, the spiral groove at the outer end of the cam post 19 rotates through the cooperation with the base box body 1, so that the left bell jar 2 and the right bell jar 3 rotate around the bell jar lifting screw 20 away from the base box body 1, which is convenient for the operator to take out or load diamond grains; During the sintering process of the diamond grains in the left bell jar 2, preparations are made for the sintering work corresponding to the right bell jar 3. When the sintering in the left bell jar 2 is completed, the right bell jar 3 completes the preparation work and starts sintering. At this time, move the piston 13 upward to push the high-temperature heat transfer agent in the liquid storage cylinder 11 into the heat exchange chamber 10 corresponding to the right bell jar 3. The heat transfer agent transfers the heat to the inner bell jar 4 in the right bell jar 3, thereby preheating the diamond grains in the right bell jar 3. After the preheating is completed, the heat transfer agent is sucked into the liquid storage cylinder 11, and then the diamond grains in the right bell jar 3 are heated and sintered by the bottom heating wire 7, the middle heating wire 8 and the top heating wire 9; Continuously repeat the above process to realize the alternate and uninterrupted sintering of the two workstations. Two controllers that are electrically connected to each other play a backup role. When one fails, the other can seamlessly connect; The effective reduction of power consumption is achieved by recycling the heat through the heat transfer agent. The bottom end of the base box body 1 is fixedly connected with universal wheels; On the basis of the variable pitch heating wire manufacturing convection in Embodiment 1, the function of driving the tray bracket 15 to rotate by a rotating motor is added, which further improves the temperature uniformity of the diamond grains on the multi-layer trays during the sintering process and ensures the product consistency.

[0073] The observation bottle 17 visually monitors the gas flow through bubbles. The hydrogen concentration sensor monitors the hydrogen concentration in real time, providing an important safety monitoring means. Especially when using dangerous gases such as hydrogen, the operation safety is improved, and the observation window is convenient for manual observation.

[0074] Automated operation and precise control of two workstations, combined with the function of preheating one workstation using the waste heat generated when the other workstation is cooling, achieve alternating and uninterrupted high-efficiency continuous production of the two workstations, greatly improving the equipment production capacity.

[0075] The heat carried by the heat-conducting agent when one workstation is cooling is used to preheat the other workstation, recovering part of the heat and effectively reducing the overall power consumption.

[0076] The bolt nuts and quick-release mechanism at the top of the sealing ring 12 provide a more reliable and convenient sealing and fixing method for the bell jar and the base box body 1.

[0077] The above are only the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the concept described herein through the above teachings or the technology or knowledge in related fields. As long as the changes and variations made by those skilled in the art do not depart from the spirit and scope of the present invention, they should all be within the protection scope of the appended claims of the present invention.

Claims

1. A diamond particle solidification and sintering furnace, characterized in that It includes two controllers electrically connected to each other and a base box body (1). At the top of the base box body (1), a left bell jar (2) and a right bell jar (3) which are symmetrically arranged left and right are provided. An inner bell jar (4) is fixedly connected inside each of the left bell jar (2) and the right bell jar (3). A heating wire bracket (5) is clamped inside each of the two inner bell jars (4). A plurality of heating wire fixing blocks (6) are clamped on the heating wire bracket (5). A bottom heating wire (7), a middle heating wire (8) and a top heating wire (9) are arranged between the heating wire brackets (5). A heat exchange chamber (10) is formed between the inner wall of the left bell jar (2) and the right bell jar (3) and the outer wall of the corresponding inner bell jar (4). A liquid storage cylinder (11) is fixedly connected inside the base box body (1) at a position between the left bell jar (2) and the right bell jar (3). The bottom ends of the two heat exchange chambers (10) are connected to the top end of the liquid storage cylinder (11) through pipes, and the top ends of the two heat exchange chambers (10) are connected to the bottom end of the liquid storage cylinder (11) through pipes. A piston (13) is slidably connected inside the liquid storage cylinder (11). At the position corresponding to the left bell jar (2) and the right bell jar (3) at the top of the base box body (1), a tray bracket (15) is rotatably connected. A rotating motor is fixedly connected inside the base box body (1) at a position corresponding to the two tray brackets (15). The bottom heating wire (7), the middle heating wire (8) and the top heating wire (9) are all arranged in a variable pitch spiral shape, and the pitch of the bottom heating wire (7), the middle heating wire (8) and the top heating wire (9) gradually increases from bottom to top. The pitch of the bottom end of the top heating wire (9) is greater than the pitch of the top end of the middle heating wire (8), and the pitch of the bottom end of the middle heating wire (8) is greater than the pitch of the top end of the bottom heating wire (7).

2. The diamond grit solidification and sintering furnace according to claim 1, characterized in that: The bottom heating wire (7), the middle heating wire (8) and the top heating wire (9) are all fixedly connected to the heating wire bracket (5) through the heating wire fixing blocks (6). Solenoid valves are installed on the pipes connecting the top and bottom ends of the two heat exchange chambers (10). Sealing rings (12) are fixedly connected to the bottom ends of the left bell jar (2) and the inner bell jar (4) and the bottom ends of the right bell jar (3) and the inner bell jar (4). Sealing rings are fixedly connected to the bottom ends of the two sealing rings (12), and the sealing rings are abutted against the top of the base box body (1).

3. A diamond diamond particle solidification and sintering furnace according to claim 1, characterized in that: The power shaft of the rotating motor is fixedly connected to the tray bracket (15). A plurality of trays for placing diamond grains are sleeved outside the tray bracket (15). A spacer ring is arranged between adjacent two trays. A gas cylinder (16) is fixedly connected inside the base box body (1). The exhaust ports of the gas cylinder (16) are respectively connected to the inner wall near the top end of the inner bell jar (4) through pipes. Solenoid valves are installed on the pipes between the gas cylinder (16) and the inner bell jar (4) and between the observation bottle (17) and the inner bell jar (4).

4. A diamond diamond particle curing and sintering furnace according to claim 3, characterized in that: At the top of the base box body (1), an observation bottle (17) is fixedly connected at a position between the left bell jar (2) and the right bell jar (3). The inner walls of the two inner bell jars (4) near their bottom ends are both connected to the inner wall of the observation bottle (17) near its bottom end through pipelines. The gas cylinder (16) is filled with hydrogen.

5. A diamond diamond particle curing and sintering furnace according to claim 1, characterized in that: The bottom heating wire (7), the middle heating wire (8), and the top heating wire (9) are all electrically connected to the controller through wires. Temperature sensors are fixedly connected to the inner walls of the inner bell jar (4) at positions corresponding to the bottom heating wire (7), the middle heating wire (8), and the top heating wire (9). The bottom end of the piston (13) is fixedly connected with a piston screw sleeve, and a piston lifting screw (14) is threadedly connected inside the piston screw sleeve.

6. The diamond diamond particle curing and sintering furnace according to claim 2, characterized in that: The top end of the sealing ring (12) is fixedly connected with a plurality of bolts. The plurality of bolts all penetrate upward through the corresponding left bell jar (2) and right bell jar (3), and the penetrated parts are all threadedly connected with nuts. The left bell jar (2) and the right bell jar (3) are respectively fixedly connected to the base box body (1) through a quick-release mechanism of the right bell jar (3).

7. A diamond diamond particle solidification and sintering furnace according to claim 5, characterized in that: The top ends of the left bell jar (2) and the right bell jar (3) are both fixedly connected with lifting screw sleeves (18) through brackets. The bottom ends of the lifting screw sleeves (18) are both fixedly connected with cam columns (19). A bell jar lifting screw (20) is threadedly connected inside the cam column (19). The bottom ends of the piston lifting screw (14) and the two bell jar lifting screws (20) are all fixedly connected with reduction motors. The plurality of reduction motors are all electrically connected to the controller. A guide groove is opened along the axial direction at the outer end of the lifting screw sleeve (18). Both the guide groove and the spiral groove are slidably connected to the base box body (1).

8. A diamond diamond particle curing and sintering furnace according to claim 7, characterized in that: A spiral groove is opened at the outer end of the cam column (19). The spiral groove is slidably connected to the base box body (1).

9. The diamond diamond particle curing and sintering furnace according to claim 3, characterized in that: The gas cylinder (16) is filled with hydrogen. The observation bottle (17) is filled with water. A hydrogen concentration sensor is fixedly connected to the top end of the observation bottle (17). The hydrogen concentration sensor is electrically connected to the controller. Observation windows are opened on the left bell jar (2), the right bell jar (3), and the inner bell jar (4).

10. A diamond particle solidification and sintering furnace according to claim 1, characterized in that: A distribution box is fixedly connected inside the base box body (1). The space above the piston (13) in the liquid storage cylinder (11) is filled with a heat transfer agent. The heat transfer agent is lead-bismuth alloy or molten salt. The volume of the liquid storage cylinder (11) is equal to the volume of the heat exchange chamber (10).

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