A phase change gypsum board and a production process thereof

Abstract

The application discloses a kind of phase change gypsum board, by gypsum powder, fixed phase change material, deionized water, water reducing agent and dispersant composition;Wherein, fixed phase change material is n-decanoic acid-octadecanol diatomite powder fixed phase change material;Water reducing agent is naphthalene water reducing agent;Dispersant is polyvinyl alcohol dispersant;The mass fraction of the admixture of naphthalene water reducing agent and dispersant is 0.6%.The application also discloses a kind of production process of phase change gypsum board, by following production process composition:The raw materials for preparing phase change gypsum board are mixed to form slurry, slurry is formed by molding, cutting and drying to obtain the phase change gypsum board;Drying uses waste heat recovery energy-saving type phase change gypsum board drying system.The application utilizes the waste heat of the first two stages, and the waste heat is reused for drying in the drying machine for the third stage of phase change gypsum board, energy saving and emission reduction;Octadecanol diatomite powder fixed phase change material with n-decanoic acid has good heat storage performance.

Description

Technical Field

[0001] This invention relates to equipment for utilizing waste heat from calcium sulfate-containing cement and energy-saving drying equipment, specifically to a phase change gypsum board and its production process. Background Technology

[0002] Phase change materials (PCMs) are highly efficient energy storage substances with advantages such as high energy density, high efficiency, and essentially constant temperature before the phase change is complete. Their heat storage capacity per unit volume is 5 to 14 times that of sensible heat storage materials such as water and rock. Furthermore, during the phase change process, PCMs store or release energy while maintaining a relatively constant temperature before the phase change is complete, forming a broad temperature plateau. This allows them to store energy during heat transfer, combining the functions of thermal resistance and heat capacity (energy storage) and extending the energy transfer time. In her paper "Research Progress on the Preparation of Phase Change Gypsum Board and its Application in Building Walls," published in the August 2016 issue of the *Journal of the Chinese Ceramic Society* (Vol. 44, No. 8), Liu Fengli mentioned that by combining phase change materials with building materials, phase change energy storage building materials can be made and applied to building envelopes. These materials can store solar energy, indoor heating, or cooling energy in the form of latent heat of phase change, realizing the conversion and utilization of energy at different times. Simultaneously, they aim to improve the heat storage capacity and thermal inertia of building envelope components, reduce indoor temperature fluctuations, improve living comfort, and achieve energy conservation and consumption reduction. Phase change gypsum board is an energy-saving building material that combines phase change materials (PCMs). It regulates indoor temperature by absorbing or releasing latent heat, improving the thermal comfort and energy efficiency of buildings. However, the drying process during its preparation still consumes a relatively high amount of energy, and there are few improvements made to address this issue. Current technologies, such as patents CN110759691B (an environmentally friendly phase change gypsum board and its preparation method) and CN111499323B (a phase change gypsum board and its preparation method), primarily focus on formulation design, with a greater emphasis on environmental protection, cost reduction, and increased strength. There are also few existing technologies that address improvements to prevent PCM leakage. Summary of the Invention

[0003] The purpose of this invention is to overcome the defects in the existing technology and provide a phase change gypsum board that uses n-decanoic acid-octadecyl alcohol diatomaceous earth powder as a shaping phase change material, which has good heat storage performance; it can effectively avoid PCM leakage; and it utilizes the waste heat from the first two stages of exhaust gas, which is then recycled for the third stage of drying of the phase change gypsum board in the dryer, thus saving energy and reducing emissions.

[0004] To achieve the above objectives, the technical solution of this invention is to design a phase change gypsum board, comprising gypsum powder, a shape-stabilizing phase change material, deionized water, a water-reducing agent, and a dispersant; wherein the shape-stabilizing phase change material is n-decanoic acid-octadecyl alcohol diatomaceous earth powder shape-stabilizing phase change material; the water-reducing agent is a naphthalene-based water-reducing agent; and the dispersant is a polyvinyl alcohol dispersant; the mass fraction of both the naphthalene-based water-reducing agent and the dispersant is 0.6%. The n-decanoic acid-octadecyl alcohol diatomaceous earth powder shape-stabilizing phase change material exhibits good heat storage performance and can effectively prevent PCM leakage.

[0005] A further technical solution is that the mass fractions of each raw material are: 100 parts gypsum powder, 15-30 parts shaping phase change material, 35 parts deionized water, 0.6 parts water-reducing agent, and 0.6 parts dispersant.

[0006] The present invention also provides a technical solution for the production process of phase change gypsum board, which consists of the following production steps: mixing the raw materials for preparing phase change gypsum board to form a slurry, and molding, cutting and drying the slurry to obtain the phase change gypsum board; the drying adopts an energy-saving phase change gypsum board drying system with waste heat recovery.

[0007] This invention utilizes the waste heat from the first two stages of exhaust gas, and reuses this waste heat for the third stage of drying phase change gypsum board in the dryer, thus saving energy and reducing emissions.

[0008] A further technical solution is that the drying process consists of sequentially performed shaping drying, deep drying, and balancing drying processes.

[0009] A further technical solution is that the shaping and drying process uses hot air at 40-60℃ with a wind speed of 2-3m / s, and the hot air is sprayed in a direction perpendicular to the surface of the phase change gypsum board.

[0010] The deep drying process uses far-infrared radiation to heat the hot air to 60-80℃;

[0011] The temperature of the balanced drying process is 30-40℃.

[0012] A further technical solution is that the energy-saving phase change gypsum board drying system is composed of a multi-layer belt dryer. The multi-layer belt dryer consists of a casing, at least three conveyor belts inside the casing, a hot air inlet on the casing, a phase change gypsum board inlet on the casing, a board outlet on the casing, a geared motor for driving the conveyor belts on the casing, and an exhaust pipe located at the lower side of the casing. The exhaust pipe is connected to a dehumidifying fan. The exhaust port of the dehumidifying fan is connected to the evaporator inlet of the heat pump, and the condenser outlet of the heat pump is connected to the opening of the casing located at the lower conveyor belt.

[0013] The machine casing is also equipped with a phase change gypsum board transfer mechanism, which is a flipping mechanism, such as a flipping arm or a robotic arm; the waste heat from the first two stages of exhaust gas is recycled for the third stage of drying of the phase change gypsum board in the dryer, thus saving energy and reducing emissions.

[0014] Another technical solution is that the machine housing also includes a phase change gypsum board transfer mechanism, which includes a high-resilience airbag. The high-resilience airbag is placed at the end edge of the conveyor belt except for the last layer of the mesh belt. An inclined slide rail is set on the side of the high-resilience airbag away from the mesh belt, and the airbag roller is rotated on the side of the slide rail facing the point where the phase change gypsum board falls. The high-resilience airbag is made of addition-curing high-temperature silicone or platinum-curing silicone. An inlet valve and an outlet valve are set on the high-resilience airbag. The inlet valve is a normally open duckbill valve, and the outlet valve is a magnetic piston valve. The height of the lowest point of the high-resilience airbag is higher than the lowest point of the inclined slide rail. When the high-resilience airbag is not compressed, its upper surface is flush with the upper surface of the mesh belt.

[0015] A nylon fiber mesh reinforcement layer is bonded to the non-contact surface of the high-resilience airbag;

[0016] This configuration minimizes the impact of the phase change gypsum board falling off the conveyor belt as it leaves its current layer, thanks to the high-resilience airbags flush with the belt surface. The inclined slide rail on one side of the high-resilience airbags guides the falling gypsum board onto the next layer's conveyor belt. The airbag rollers on the inclined slide rails further prevent the impact of the gypsum board transferring from the high-resilience airbags to the inclined slide rails and provide additional guidance.

[0017] Compared to existing technologies, the transfer mechanism in this embodiment eliminates the need for power mechanisms (such as the clamping and flipping mechanism of the flap; the compressed air nozzle for air flotation-assisted transfer), thus saving energy and reducing the need for drying equipment mechanisms. Furthermore, it provides good buffering effect, minimizing the risk of PCM vibration leakage during the transfer process.

[0018] Another technical solution is that the conveyor belt includes two parallel steel belts; two steel bars with a gap can be set between the two steel belts to connect the two steel belts, and the two ends of the steel bars are fixedly connected to the two steel belts respectively (when the phase change gypsum board is placed on the steel belt, the steel bars are avoided); the gap between the two steel belts, that is, the length of the steel bars, is slightly larger than the width of the cut (i.e., the phase change gypsum board to be dried); the transfer mechanism includes several uniformly arranged grooves on the side of the steel belt, and rubber columns are slidably arranged in the grooves. The end of the rubber column located in the groove is fixedly connected to a magnet embedded spring (permanent magnets are embedded in the spring or at both ends). When the magnet embedded spring is not under force, the end of the rubber column away from the magnet embedded spring extends beyond the groove opening. An electromagnet is set on the bottom wall of the groove, and an induction coil is arranged below the steel belt. A matching receiving end is set in the electromagnet.

[0019] With this setup, no power mechanism (such as the clamping and flipping mechanism of the flip plate; the compressed air nozzle for air flotation-assisted transfer) is needed, which saves energy and reduces the number of drying equipment mechanisms. On the other hand, the buffering effect is also good. Since rubber columns are set on the entire side of the steel belt, vibration can be reduced when receiving phase change gypsum board falling from above, avoiding the problem of PCM vibration leakage during the transfer process.

[0020] Another technical solution involves a transfer mechanism comprising several evenly arranged through holes on the side of a steel belt. A rubber column is slidably installed within each through hole, with one end of the rubber column located within a groove and its end fixedly connected to the exposed end of the piston rod of a hydraulic cylinder. An annular oil pipe, serving as the main oil supply circuit, is arranged outside the steel belt. Each hydraulic cylinder is connected to the annular oil pipe via a short flexible hose and moves with the belt. A sliding sealing joint is installed on the annular oil pipe, and the short flexible hose is connected to it via a movable plug. The annular oil pipe is made of rigid metal. The movable plug has a wear-resistant sealing ring (such as PTFE or PU) inside (the movable plug maintains contact pressure via a spring or air pressure to prevent leakage). The short flexible hose (such as a PUR / PVC reinforced hose) connects the hydraulic cylinder and the movable plug.

[0021] Each valve on the short flexible hose is equipped with a wireless receiver module (such as Bluetooth, Zigbee, or industrial RF), and the controller connects to the valve via wireless signals. The valves are powered by batteries.

[0022] As the rubber column retracts into the side of the steel belt, the phase change gypsum board underneath falls below, achieving layer-by-layer dropping (and utilizing the lower steel belt between the two conveyor rollers of each layer. Although phase change gypsum board is placed on both the upper and lower steel belts of each layer, this setup actually reduces the number of layers; the transmission distance of each layer is twice that of the original. Although the presence of gypsum board on both the top and bottom of each layer slightly reduces the heat transfer effect, thus reducing the drying effect to some extent, the increased transmission distance, i.e., the longer drying time, compensates for this, and overall improves the drying effect. Therefore, reducing the number of layers can achieve a similar drying effect and time as before). This eliminates the need for a flipping mechanism or air flotation mechanism, and also eliminates the need for a stepped drop ramp, saving energy and reducing the footprint of the entire equipment; the rubber column is used for elastic support to reduce vibration and impact during dropping.

[0023] The advantages and beneficial effects of this invention are as follows: This invention utilizes the waste heat from the first two stages of exhaust gas and reuses the waste heat for the third stage of drying phase change gypsum board in the dryer, thereby saving energy and reducing emissions.

[0024] The high-resilience airbags, flush with the surface of the conveyor belt, minimize the impact of the phase change gypsum board falling as it leaves the belt. The inclined slide rail on one side of the high-resilience airbag guides the falling phase change gypsum board onto the next layer of the conveyor belt. The airbag rollers on the inclined slide rail prevent the phase change gypsum board from being transferred from the high-resilience airbag to the inclined slide rail and also provide further guidance.

[0025] It eliminates the need for power mechanisms (such as the clamping and flipping mechanism of the flip plate; the compressed air nozzle for air flotation-assisted transfer), thus saving energy and reducing the number of drying equipment mechanisms. On the other hand, it also has a good buffering effect. Since rubber columns are set on the entire side of the steel belt, it can reduce vibration when receiving phase change gypsum board falling from above, and avoid the problem of PCM vibration leakage during the transfer process. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of an energy-saving phase change gypsum board drying system in Embodiment 1 of the present invention;

[0027] Figure 2 yes Figure 1 Perspective view of the casing of the central engine;

[0028] Figure 3 yes Figure 2 A three-dimensional schematic diagram of the conveyor belt;

[0029] Figure 4 This is a schematic diagram of Embodiment 2 of the present invention;

[0030] Figure 5 yes Figure 4 Another schematic diagram of the working state;

[0031] Figure 6 This is a schematic diagram of the conveyor belt in Embodiment 3 of the present invention;

[0032] Figure 7 yes Figure 6 A top view of the upper conveyor belt;

[0033] Figure 8 yes Figure 7 A partially enlarged schematic diagram of the rubber column and its surrounding components;

[0034] Figure 9 yes Figure 8 A partially enlarged schematic diagram of the magnet embedded in the spring and its surrounding components;

[0035] Figure 10 yes Figure 6 Another schematic diagram of the working state;

[0036] Figure 11 This is a top view of a single-layer conveyor belt in Embodiment 4 of the present invention;

[0037] Figure 12 yes Figure 11 A partially enlarged schematic diagram of the central rubber column and its surrounding components;

[0038] Figure 13 This is a front view of the conveyor belt in Embodiment 4 of the present invention.

[0039] In the diagram: 1. Machine casing; 2. Conveyor belt; 3. Hot air inlet; 4. Phase change gypsum board inlet; 5. Board outlet; 6. Gear motor; 7. Exhaust pipe; 8. Dehumidifying fan; 9. Heat pump; 10. Opening; 11. Far-infrared radiation plate; 12. High-resilience airbag; 13. Inclined slide rail; 14. Airbag roller; 15. Steel belt; 16. Steel bar; 17. Rubber column; 18. Phase change gypsum board; 19. Magnet embedded spring; 20. Electromagnet; 21. Conveyor roller; 22. Photoelectric sensor; 23. Through hole; 24. Hydraulic cylinder. Detailed Implementation

[0040] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0041] Example 1: As Figures 1 to 3 As shown (for ease of illustration), Figure 2 (The flip-plate mechanism is not shown in the figure). This invention is a phase change gypsum board, which is composed of gypsum powder, a shaping phase change material, deionized water, a water-reducing agent, and a dispersant; wherein, the shaping phase change material is n-decanoic acid-octadecyl alcohol diatomaceous earth powder shaping phase change material; the water-reducing agent is a naphthalene-based water-reducing agent; the dispersant is a polyvinyl alcohol dispersant; the mass fraction of both the naphthalene-based water-reducing agent and the dispersant is 0.6%.

[0042] The mass fractions of each raw material are as follows: 100 parts gypsum powder, 15-30 parts shaping phase change material, 35 parts deionized water, 0.6 parts water-reducing agent, and 0.6 parts dispersant.

[0043] The n-decanoic acid-octadecyl alcohol diatomaceous earth powder-based phase change material is prepared by using a eutectic mixture of n-decanoic acid and octadecyl alcohol and modified diatomaceous earth powder. The eutectic mixture of n-decanoic acid and octadecyl alcohol is prepared by a melt method, wherein the mass ratio of n-decanoic acid to octadecyl alcohol is 85:15, the phase change temperature is 27.95℃, and the phase change enthalpy is 154.2 J / g. The modified diatomaceous earth powder is prepared by removing impurities from the pores of the diatomaceous earth using a calcination-acid washing method: the diatomaceous earth powder is calcined at 600℃ for 2 hours, followed by acid washing with 5 mol / L hydrochloric acid solution at 40℃ for 12 hours. The modified diatomaceous earth is then dried in a 100℃ electric thermostatic drying oven to constant weight, ensuring complete evaporation of moisture from the pores and full opening of the pore structure. The eutectic mixture of decanoic acid and octadecyl alcohol was melted and liquefied, then dripped into dried modified diatomaceous earth. The mass ratio of the eutectic mixture of decanoic acid and octadecyl alcohol to the modified diatomaceous earth was 35:65. After stirring at 80℃ for 10 min, the mixture was poured into a glass petri dish and spread evenly. The petri dish was placed in a vacuum drying oven, with the oven temperature set at 60℃ and the vacuum degree at 0.04 MPa. After adsorption for 60 min, the mixture was removed and ground into powder to obtain the decanoic acid-octadecyl alcohol diatomaceous earth powder shaped phase change material.

[0044] A production process for phase change gypsum board comprises the following steps: mixing the raw materials for preparing phase change gypsum board to form a slurry; molding, cutting and drying the slurry to obtain the phase change gypsum board; and using an energy-saving phase change gypsum board drying system with waste heat recovery for drying.

[0045] The drying process consists of sequential shaping drying, deep drying, and equilibrium drying.

[0046] The shaping and drying process uses hot air at 40-60℃ with a wind speed of 2-3m / s, and the hot air is sprayed in a direction perpendicular to the surface of the phase change gypsum board.

[0047] The deep drying process uses far-infrared radiation to heat the hot air to 60-80℃;

[0048] The temperature of the balanced drying process is 30-40℃.

[0049] The energy-saving phase change gypsum board drying system consists of a multi-layer belt dryer, which comprises a casing 1, three conveyor belts 2 inside the casing (the conveyor belts of the multi-layer belt dryer are existing technology, generally using steel belts or Teflon-coated mesh belts with several evenly arranged ventilation holes to facilitate heat transfer to the phase change gypsum board), a hot air inlet 3 on the casing, a phase change gypsum board inlet 4 on the casing, a board outlet 5 on the casing, a geared motor 6 on the casing to drive the conveyor belts, and an exhaust pipe 7 located at the lower side of the casing; the exhaust port of the dehumidifying fan 8 is connected to the evaporator inlet of the heat pump 9, and the condenser outlet of the heat pump is connected to the opening 10 located on the lower conveyor belt of the casing.

[0050] Exhaust pipe 7 is connected to the dehumidifying fan; hot air inlet 3 is located at the top of the machine casing, phase change gypsum board inlet 4 is located on the side of the machine casing, and board outlet 5 is located on the opposite side. Three conveyor belts 2 are arranged sequentially from top to bottom, forming the upper drying layer, middle drying layer, and lower drying layer respectively. The output shaft of the geared motor 6 passes through the machine casing 1 and is connected to the roller shaft of the conveyor roller of the conveyor belt 2. Hot air is input into the machine casing through the hot air inlet, and the shaped and cut phase change gypsum board enters the multi-layer belt dryer through the phase change gypsum board inlet 4. After the upper conveyor belt 2 delivers the phase change gypsum board to its end, a flipping mechanism clamps and flips the board before placing it onto the lower conveyor belt (the flipping mechanism is existing technology, such as a flipping arm / robotics, which will not be described in detail). Hot air blown to the middle layer is heated to 60-80℃ by the far-infrared radiation plate 11 (fixed at the middle height of the machine casing). Drying continues at the third layer, where the air velocity is even lower. Another flipping mechanism transfers the middle layer's phase change gypsum board to the lower layer. A high-pressure fan array can be installed at the hot air inlet 3, working in conjunction with a uniform air distribution plate to ensure even airflow. Hot air enters from the top of the machine casing. The upper conveyor belt inside the casing is the first stage: the shaping and drying stage, used to quickly remove moisture from the gypsum board surface, forming a porous structure and preventing the phase change material (PCM) from migrating with the moisture. The middle conveyor belt is the second stage: the deep drying stage, with parameters of 60-80℃ medium-temperature hot air + far-infrared radiation plate (wavelength 2.5-5μm). Its function is to allow infrared rays to penetrate the surface of the gypsum board, promoting internal moisture diffusion; and to allow hot air to carry away evaporated moisture. The infrared module can be controlled in zones, dynamically starting and stopping based on feedback from the board's moisture content sensor. The lower conveyor belt is the third stage: the balancing drying stage, with parameters of 30-40℃ low-temperature waste heat (from heat pump recovery) + low-speed air circulation. It utilizes the waste heat from the first two stages. Its function is to balance the moisture content of the board to ≤1%.

[0051] The exhaust gas from the dehumidifying fan 8 is introduced into the evaporator inlet of the heat pump 9 for dehumidification and cooling. Then, it is mixed with the replenished fresh air and enters the condenser inlet of the heat pump. After being heated by the heat pump, it re-enters the lower conveyor belt of the dryer.

[0052] Example 2: The difference from Example 1 is that, as shown in Example 2... Figure 4 , Figure 5As shown, a high-resilience airbag 12 is installed inside the machine housing. The high-resilience airbag is positioned at the edge of the conveyor end except for the last layer of mesh belt (i.e., conveyor belt 2). An inclined slide rail 13 is installed on the side of the high-resilience airbag away from the mesh belt (the inclined slide rail can also be an airbag, with both sides of the inclined slide rail fixedly connected to the inner wall of the machine housing). An airbag roller 14 is rotatably installed on the inclined slide rail 13 facing the falling point of the phase change gypsum board (the airbag roller slightly protrudes from the upper inclined plane of the inclined slide rail). The high-resilience airbag 12 is made of addition-curing high-temperature silicone or platinum-curing silicone. An inlet valve and an outlet valve are installed on the high-resilience airbag. The inlet valve is a normally open duckbill valve, and the outlet valve is a magnetic piston valve. The height of the lowest point of the high-resilience airbag is higher than the lowest point of the inclined slide rail 13.

[0053] A nylon fiber mesh reinforcement layer is bonded to the non-contact surface of the high-resilience airbag;

[0054] The high-elasticity silicone or polyurethane film is 0.5-1mm thick; these materials can quickly return to their original shape after being deformed under pressure (rebound time <0.5 seconds). Inlet valve: Normally open duckbill valve (opening pressure 0.1kPa), allowing free air entry. Outlet valve: Magnetic piston valve (trigger pressure 2kPa), which opens the exhaust port through magnetic displacement under pressure. A reinforced structure is incorporated: a nylon fiber mesh reinforcement layer is added to the non-contact surface of the airbag to prevent excessive expansion.

[0055] The drying temperature range of the multi-layer belt dryer for phase change gypsum board is as follows: Core range: 40–55℃; Lower limit (40℃): Ensures the rate of dehydration of gypsum (calcium sulfate dihydrate) into hemihydrate gypsum, avoiding insufficient drying that leads to a decrease in strength. Upper limit (55℃): Does not exceed the phase change temperature of common PCMs (such as paraffin wax, fatty acids) (usually ≤60℃), preventing microcapsule rupture or PCM melting and leakage.

[0056] The airbag material uses addition-curing high-temperature silicone (such as Dow Corning Silastic HT-3000) or platinum-curing silicone; 200D aramid mesh (80g / m²) can also be laminated on the non-stressed surface of the airbag to improve high-temperature dimensional stability; the edges of the airbag are made with a molding edge-wrapping process (width ≥ 5mm) to prevent thermal stress cracking; this enables rapid air release under pressure (response time < 50ms), and 90% volume recovery within 3 seconds after pressure is released.

[0057] This configuration minimizes the impact of the phase change gypsum board falling off the conveyor belt as it leaves its current layer, thanks to the high-resilience airbags flush with the belt surface. The inclined slide rail on one side of the high-resilience airbags guides the falling gypsum board onto the next layer's conveyor belt. The airbag rollers on the inclined slide rails further prevent the impact of the gypsum board transferring from the high-resilience airbags to the inclined slide rails and provide additional guidance.

[0058] In existing technologies, when transferring gypsum board from the upper to the lower layer in a multi-layer belt dryer, it is crucial to ensure a smooth transition while preventing board breakage or damage to the phase change material (PCM) microcapsules due to mechanical movement. Currently, common methods include flip-plate transfer, drop-sliding transfer, or air flotation-assisted transfer. Air flotation-assisted transfer or low-stress flip-plate design is preferred to ensure the integrity of the functional materials. Flip-plate transfer requires "clamping-flipping-placing" the board from the upper conveyor belt to the lower conveyor belt. Drop-sliding transfer requires a stepped drop between the end of the upper conveyor belt and the beginning of the lower conveyor belt, allowing the board to slide naturally to the lower layer under gravity. Air flotation-assisted transfer requires compressed air nozzles in the transfer area to form an air cushion layer, allowing the board to "suspend" and slide horizontally to the lower layer.

[0059] Compared to existing technologies, this embodiment eliminates the need for power mechanisms (such as the clamping and flipping mechanism of the flip plate; the compressed air nozzle for air flotation-assisted transfer), thus saving energy and reducing the number of drying equipment components. Furthermore, it provides good buffering effect, minimizing the risk of PCM vibration leakage during the transfer process.

[0060] Example 3: The difference from Example 1 is that, as shown in Example 3... Figures 6 to 10 As shown, the conveyor belt includes two parallel steel belts 15; two steel bars 16 with a spacing can be set between the two steel belts to connect the two steel belts, and the two ends of the steel bars are fixedly connected to the two steel belts respectively (when the phase change gypsum board is placed on the steel belt, the steel bars are avoided); the spacing between the two steel belts, that is, the length of the steel bars, is slightly larger than the width of the cut (i.e., the phase change gypsum board to be dried) 18; several evenly arranged grooves are set on the side of the steel belt, and rubber columns 17 are slidably set in the grooves. The end of the rubber column located in the groove is fixedly connected to a magnet embedded spring 19 (permanent magnets are embedded in the spring or at both ends). When the magnet embedded spring is not under force, the end of the rubber column away from the magnet embedded spring extends beyond the groove opening. An electromagnet 20 is set on the bottom wall of the groove, and an induction coil is arranged below the steel belt. A matching receiving end is set in the electromagnet.

[0061] The steel strip can also be equipped with a ventilation hole structure similar to that on the mesh belt to enhance the heat transfer effect (for example, several evenly arranged through holes are set on the steel strip) to avoid the problem of poor drying effect at the edge of the phase change gypsum board placed on the steel strip; several evenly arranged through holes are also set on the rubber column to enhance the heat transfer effect on the phase change gypsum board.

[0062] The steel strip is wound around the conveyor roller 21. Each layer of the conveyor belt consists of a steel strip located above the two conveyor rollers and a steel strip located below the two conveyor rollers (generally horizontally arranged, so there are two horizontal surfaces). A photoelectric sensor 22 is set on the horizontal surface of the steel strip above the two conveyor rollers, and the photoelectric sensor is set close to the conveyor rollers. (This way, once the phase change gypsum board about to leave this layer reaches the end of the conveyor of this layer, the photoelectric sensor will detect it. The controller will receive the signal sent by the photoelectric sensor and control the electromagnets 20 near the conveyor rollers to be energized, so that the magnets are inserted into the springs 19. The rubber column 17 retracts into the groove, and the phase change gypsum board that has reached the end of the conveyor of this layer falls onto the horizontal surface of the steel strip below the two conveyor rollers of this layer, that is, it falls onto the steel strip below the two conveyor rollers. Since there are also rubber columns on the side of the steel strip below, it falls onto the steel strip below this layer and then moves with it.)

[0063] The photoelectric sensor model is Banner Q45 series (temperature resistance up to 70~85℃);

[0064] The electromagnet is a high-temperature type. The model can be selected from the Bürkert 6014 series (temperature resistance 120℃, IP65, suitable for long-term operation) or the Festo EMMS series (with temperature sensor, current can be adjusted in real time).

[0065] With this setup, no power mechanism (such as the clamping and flipping mechanism of the flip plate; the compressed air nozzle for air flotation-assisted transfer) is needed, which saves energy and reduces the number of drying equipment mechanisms. On the other hand, the buffering effect is also good. Since rubber columns are set on the entire side of the steel belt, vibration can be reduced when receiving phase change gypsum board falling from above, avoiding the problem of PCM vibration leakage during the transfer process.

[0066] Example 4: The difference from Example 3 is that, as shown in Example 4... Figures 11 to 13 As shown, several evenly arranged through holes 23 are provided on the side of the steel belt. A rubber column 17 is slidably installed in each through hole. The end of the rubber column located in the groove is fixedly connected to the exposed end of the piston rod of the oil cylinder 24. An annular oil pipe, serving as the main oil supply circuit, is arranged on the outside of the steel belt. Each oil cylinder is connected to the annular oil pipe via a short hose and moves with the belt. A sliding sealing joint is installed on the annular oil pipe, and the short hose is connected to it via a movable plug. The annular oil pipe is made of rigid metal. The movable plug has a wear-resistant sealing ring (such as polytetrafluoroethylene PTFE or polyurethane PU) inside (the movable plug maintains contact pressure by spring or air pressure to prevent leakage). The short hose is made of flexible high-pressure hose (such as PUR / PVC reinforced pipe) to connect the oil cylinder and the movable plug.

[0067] Each valve on the short flexible hose is equipped with a wireless receiver module (such as Bluetooth, Zigbee, or industrial RF), and the controller connects to the valve via wireless signals. The valves are powered by batteries.

[0068] The steel strip is wound around the conveyor rollers, so each layer of the conveyor belt consists of a steel strip located above the two conveyor rollers and a steel strip located below the conveyor rollers (generally horizontally arranged, thus having two horizontal planes, upper and lower); photoelectric sensors 22 are installed on the horizontal plane of the steel strip above the two conveyor rollers, and the photoelectric sensors are positioned close to the conveyor rollers (so that once the phase change gypsum board about to leave this layer reaches the end of the conveyor of this layer, the photoelectric sensor will detect it, and the controller will receive the signal sent by the photoelectric sensor and control the valves on the short hoses of the hydraulic cylinders near the conveyor rollers to open (pre-set)). Based on the size of the phase change gypsum board and the arrangement of the hydraulic cylinders, the spacing between adjacent hydraulic cylinders, once the controller receives a signal, it controls the hydraulic cylinders under the phase change gypsum board closest to the end of the conveying process to move (while other hydraulic cylinders remain stationary). This causes the piston rod of the hydraulic cylinder to retract, and the rubber column retracts into the groove. The phase change gypsum board that has reached the end of the conveying process on this layer falls onto the horizontal surface of the steel belt located below the two conveyor rollers on this layer, that is, it falls onto the steel belt below the two conveyor rollers. Since there are also rubber columns on the side of the steel belt below, it falls onto the steel belt below this layer and then moves accordingly.

[0069] As the rubber column retracts into the side of the steel belt, the phase change gypsum board underneath falls below, achieving layer-by-layer dropping (and utilizing the lower steel belt between the two conveyor rollers of each layer. Although phase change gypsum board is placed on both the upper and lower steel belts of each layer, this setup actually reduces the number of layers; the transmission distance of each layer is twice that of the original. Although the presence of gypsum board on both the top and bottom of each layer slightly reduces the heat transfer effect, thus reducing the drying effect to some extent, the increased transmission distance, i.e., the longer drying time, compensates for this, and overall improves the drying effect. Therefore, reducing the number of layers can achieve a similar drying effect and time as before). This eliminates the need for a flipping mechanism or air flotation mechanism, and also eliminates the need for a stepped drop ramp, saving energy and reducing the footprint of the entire equipment; the rubber column is used for elastic support to reduce vibration and impact during dropping.

[0070] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for the production of a phase change gypsum board, characterized in that, The production process consists of the following steps: mixing the raw materials for preparing phase change gypsum board to form a slurry; molding, cutting and drying the slurry to obtain the phase change gypsum board; and using an energy-saving phase change gypsum board drying system with waste heat recovery for drying. The drying process adopts an energy-saving phase change gypsum board drying system with waste heat recovery, which consists of a multi-layer belt dryer. The multi-layer belt dryer includes at least three conveyor belts and a phase change gypsum board transfer mechanism. The conveyor belt consists of two parallel steel belts; two steel bars with a gap are set between the two steel belts to connect the two steel belts, and the two ends of the steel bars are fixedly connected to the two steel belts respectively; the gap between the two steel belts, that is, the length of the steel bars, is greater than the width of the phase change gypsum board after cutting. The transfer mechanism includes several evenly arranged through holes on the side of the steel belt. A rubber column is slidably installed in each through hole. The end of the rubber column located in the groove is fixedly connected to the exposed end of the piston rod of the hydraulic cylinder. An annular oil pipe, serving as the main oil supply circuit, is arranged on the outside of the steel belt. Each hydraulic cylinder is connected to the annular oil pipe via a short hose and moves with the belt. A sliding sealing joint is installed on the annular oil pipe, and the short hose is connected to it via a movable plug. The annular oil pipe is made of rigid metal. The movable plug has a wear-resistant sealing ring inside. The movable plug maintains contact pressure by spring or air pressure to prevent leakage. The short hose is a flexible high-pressure hose connecting the hydraulic cylinder and the movable plug. Each valve on the short hose is equipped with a wireless receiving module, and the controller is connected to the valve signal via a wireless signal. The valves are powered by batteries.

2. A process for the production of phase change gypsum board according to claim 1, characterized in that, The drying process consists of sequential shaping drying, deep drying, and equilibrium drying.

3. A process for the production of phase change gypsum board according to claim 2, characterized in that, The shaping and drying process uses hot air at 40-60℃ with a wind speed of 2-3m / s, and the hot air is sprayed in a direction perpendicular to the surface of the phase change gypsum board. The deep drying process uses far-infrared radiation to heat the hot air to 60-80℃; The temperature of the balanced drying process is 30-40℃.

4. A process for the production of phase change gypsum board according to claim 3, characterized in that, The energy-saving phase change gypsum board drying system consists of a multi-layer belt dryer, which comprises a casing, at least three conveyor belts inside the casing, a hot air inlet on the casing, a phase change gypsum board inlet on the casing, a board outlet on the casing, a geared motor for driving the conveyor belts on the casing, and an exhaust pipe located at the lower side of the casing. The exhaust pipe is connected to a dehumidifying fan. The exhaust port of the dehumidifying fan is connected to the evaporator inlet of the heat pump, and the condenser outlet of the heat pump is connected to the opening on the lower conveyor belt of the casing.

5. A phase change gypsum board prepared by the production process according to claim 4, characterized in that, It is composed of gypsum powder, shape-stabilizing phase change material, deionized water, water-reducing agent and dispersant; wherein, the shape-stabilizing phase change material is n-decanoic acid-octadecyl alcohol diatomaceous earth powder shape-stabilizing phase change material; the water-reducing agent is naphthalene-based water-reducing agent; the dispersant is polyvinyl alcohol dispersant; the mass fraction of naphthalene-based water-reducing agent and dispersant is 0.6%.

6. A phase change gypsum board according to claim 5, characterized in that The mass fractions of each raw material are as follows: 100 parts gypsum powder, 15-30 parts shaping phase change material, 35 parts deionized water, 0.6 parts water-reducing agent, and 0.6 parts dispersant.

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