Heat recovery type raw material preheater

Abstract

The invention provides a heat recovery type raw material preheater, which belongs to the technical field of dry mortar production and comprises a transmission mechanism, a preheating mechanism, a heat recovery mechanism and a heating mechanism. Wherein the transmission mechanism is assembled at the feeding end of the sand material drying machine and is used for conveying wet sand raw materials; the primary preheating mechanism is arranged on the conveying mechanism, comprises a primary preheating chamber with a semi-closed structure, and can perform uniform primary preheating on the wet sand raw materials conveyed on the conveying mechanism; one end of the primary heat recovery mechanism is connected with a waste heat discharge port of the sand dryer in a sealed mode, the other end of the primary heat recovery mechanism extends to one side of the primary preheating chamber, the primary heat recovery mechanism is used for recovering waste heat discharged by the dryer, and the primary heat recovery mechanism comprises a plurality of nozzles which are evenly distributed on one side of the primary preheating chamber in the length direction of the primary preheating chamber; and wind power guidance is provided for sand grains preheated by the primary preheating chamber. The device can fully utilize the waste heat of the dryer to perform stepped waste heat recovery, fully preheat the wet sand, improve the subsequent wet sand drying effect and reduce the energy consumption cost.

Description

Technical Field

[0001] This application relates to the field of dry mortar production technology, and more specifically, to a heat recovery type raw material preheater. Background Technology

[0002] As a core component of green building in the modern construction industry, the performance of dry mortar is closely related to the quality of raw material pretreatment. Dry mortar is made by mixing sand, cement, admixtures, etc. in proportion, with sand being the main material. Its moisture content directly affects the stability of subsequent production processes and the quality of the finished product. If the moisture content of the sand is too high, it will easily lead to premature hydration of cement, destroying the accuracy of the mix proportions, and will also shorten the storage life of the dry mortar product. Therefore, the drying treatment of sand has become an indispensable key pretreatment process before the preparation of dry mortar. In current industrial production, the mainstream method for drying sand is to use a drum dryer. This dryer uses a furnace to burn natural gas, coal, or biomass fuel to generate high-temperature hot air. The wet sand rotates inside the drum and comes into full contact with the high-temperature hot air, achieving rapid evaporation of moisture. However, when wet sand comes into direct contact with the high-temperature hot air, the surface moisture evaporates rapidly, forming a hard shell. This causes the sand particles to clump together, which not only reduces drying efficiency but also affects the uniformity of the dried sand. Therefore, it is necessary to heat-treat the wet sand before drying. The existing preheating process relies on waste heat resources. This involves installing a waste heat sleeve on the outside of the conveying pipe between the quantitative feeder and the dryer inlet, and then passing the dryer or boiler into the sleeve to preheat it. The waste heat from the pipe wall is used to preheat the wet sand, thus initially achieving the recovery and reuse of preheated material. However, the wet sand tends to accumulate in the conveying pipe. Only the sand particles near the inner wall of the pipe can directly contact the closed waste heat sleeve to achieve heat transfer and preheating. The sand particles accumulated inside are in a non-direct contact area, resulting in extremely low heat transfer efficiency. This leads to uneven temperature and humidity distribution of the sand particles after preheating, further affecting the proportioning accuracy of the dry mortar and the stability of the finished product performance. Meanwhile, in traditional dry sand drying processes, waste heat from the dryer exhaust is often directly emitted, carrying a large amount of heat, which not only causes serious energy waste but also generates thermal pollution.

[0003] Therefore, there is an urgent need for a heat recovery type raw material preheater. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the prior art or related technologies.

[0005] Therefore, this application provides a heat recovery type raw material preheater that can make full use of the waste heat of the dryer to perform step-by-step waste heat recovery, fully preheat the wet sand, improve the subsequent wet sand drying effect and reduce energy consumption costs.

[0006] This application provides a heat recovery type raw material preheater, which includes a transmission mechanism, a preheating mechanism, a heat recovery mechanism, and a heating mechanism. The system includes: a conveying mechanism mounted at the feed end of the sand dryer for conveying wet sand raw materials; a primary preheating mechanism mounted on the conveying mechanism, comprising a semi-enclosed primary preheating chamber for uniformly preheating the wet sand raw materials conveyed on the conveying mechanism; a primary heat recovery mechanism, one end of which is sealed to the exhaust port of the sand dryer, and the other end extending to one side of the primary preheating chamber for recovering the exhaust gas emitted by the dryer, the primary heat recovery mechanism comprising multiple nozzles evenly distributed along one side of the primary preheating chamber to provide airflow guidance for the sand particles preheated in the primary preheating chamber using the exhaust gas of the dryer; a secondary heat recovery mechanism connected to the primary preheating mechanism for collecting the exhaust gas of the primary preheating chamber to achieve cascade recovery of waste heat; a secondary preheating mechanism mounted on one side of the conveying mechanism and connected to the secondary heat recovery mechanism for secondary preheating of the wet sand that was not blown off and was still attached to the primary preheating chamber, and utilizing the heat energy recovered by the secondary heat recovery mechanism; and a heating mechanism mounted on the secondary preheating mechanism for providing an additional heat source.

[0007] In some embodiments, the conveying mechanism includes: a support base fixedly mounted on the sand dryer; two legs symmetrically mounted on the top of the support base; a conveyor belt rotatably mounted on the two legs; a first support frame mounted on one side of the top of the conveyor belt; and a receiving hopper fixedly mounted on the first support frame, with a gap reserved between the output end of the receiving hopper and the conveyor belt.

[0008] In some embodiments, the primary preheating mechanism includes: a primary preheating chamber covered on the conveyor belt; an aggregation frame disposed on one side of the primary preheating chamber, with a guide groove formed on the inner wall of the primary preheating chamber near the aggregation frame; a connecting pipe disposed at the output end of the aggregation frame; a cyclone dust collector connected to the end of the connecting pipe away from the aggregation frame, wherein the connecting pipe and the cyclone dust collector are tangentially arranged, and the cyclone dust collector has a funnel-shaped structure; and two support blocks fixedly disposed on the support base, wherein the cyclone dust collector is mounted and fixed on the two support blocks.

[0009] In some embodiments, the cyclone dust collector includes: a sand discharge pipe disposed at the bottom of the funnel-shaped structure of the cyclone dust collector; and an exhaust pipe coaxially disposed at the top of the cyclone dust collector with the sand discharge pipe, the sand discharge pipe extending into the interior of the cyclone dust collector, and a uniform annular gap forming between the outer wall of the sand discharge pipe and the inner wall of the cyclone dust collector.

[0010] In some embodiments, the primary heat recovery mechanism includes: a plurality of tube frames fixedly disposed on the side of the primary preheating chamber away from the gathering frame; a preheating air duct disposed on the plurality of tube frames, one end of which is sealed to the waste heat discharge port of the sand dryer, and the other end of which extends to one side of the primary preheating chamber; a diffusion nozzle disposed on one end of the preheating air duct near the feed end of the primary preheating chamber; and a plurality of impact nozzles evenly spaced on the preheating air duct and facing the interior of the primary preheating chamber.

[0011] In some embodiments, the secondary heat recovery mechanism includes: a heat exchange chamber connected to the outlet end of the exhaust pipe; a plurality of heat exchange tubes arranged in a rectangular array inside the heat exchange chamber, each heat exchange tube penetrating the inner cavity of the heat exchange chamber; two exhaust vents located on both sides of the heat exchange chamber; a pipe cover removably covering any of the exhaust vents; and two first fans respectively located inside each of the exhaust vents.

[0012] In some embodiments, the secondary preheating mechanism includes: a second support frame, fixedly mounted on the support base; a secondary preheating chamber, mounted on the second support frame, the inner cavity of the secondary preheating chamber communicating with the inner cavity of each heat exchange tube; a shielding cover, covering the end of the conveyor belt away from the receiving hopper, the inner cavity of the shielding cover communicating with the inner cavity of the primary preheating chamber; a scraper, mounted on the secondary preheating chamber, with the cutting edge of the scraper abutting against the surface of the conveyor belt; and a diversion plate assembly, mounted inside the secondary preheating chamber.

[0013] In some embodiments, the heating mechanism includes: a connecting cover, one end of which is connected to the heat exchange chamber and the other end of which is connected to the secondary preheating chamber, wherein the inner cavity of the connecting cover is connected to the inner cavity of each heat exchange tube; a second fan, disposed inside the connecting cover; and a heating rod, disposed inside the connecting cover and located on the side of the second fan near the secondary preheating chamber.

[0014] In some embodiments, the drainage plate group consists of a plurality of drainage plates, and each of the drainage plates is inclined.

[0015] In some embodiments, the sand discharge pipe of the cyclone dust collector is connected to the feed pipe of the sand dryer.

[0016] Compared with the prior art, the technical solution provided in this application includes at least the following technical effects: This application provides a heat recovery type raw material preheater that can fully utilize the waste heat of the dryer for stepped waste heat recovery, effectively preheating wet sand, improving the subsequent wet sand drying effect and reducing energy consumption costs. It adopts a primary and secondary stepped waste heat recovery design, accurately recovering the high-temperature waste heat emitted from the sand dryer and the low-temperature waste heat after the primary preheating. This fully converts the originally directly emitted waste heat into preheating heat energy, achieving energy recycling and significantly reducing reliance on additional energy during the preheating process, effectively reducing energy consumption costs. Furthermore, through the synergistic design of staged preheating and wind-guided dispersion, the primary preheating utilizes evenly distributed nozzles to ensure sufficient contact between hot air and wet sand, avoiding uneven waste heat caused by wet sand accumulation. The secondary preheating provides supplementary preheating for residual wet sand, ensuring that all wet sand entering the dryer meets the temperature standard and has a uniform moisture content. This prevents the problem of surface drying and clumping caused by excessive temperature differences after wet sand directly enters the dryer, ensuring the subsequent drying effect and sand quality.

[0017] Additional aspects and advantages of this application will become apparent in the following description or may be learned by practice of this application. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the overall structure of a raw material preheater according to some embodiments of this application; Figure 2 This is a schematic diagram of the transmission mechanism in some embodiments of this application; Figure 3 This is a schematic diagram of the structure of a primary preheating chamber according to some embodiments of this application; Figure 4 This is a schematic diagram of the structure of a primary preheating mechanism according to some embodiments of this application; Figure 5 This is a schematic diagram of the structure of a primary heat recovery mechanism according to some embodiments of this application; Figure 6 This is a schematic diagram of the structure of a primary preheating chamber and a cyclone dust collector according to some embodiments of this application; Figure 7 This is a schematic diagram of the secondary heat recovery mechanism in some embodiments of this application; Figure 8 This is a schematic diagram of the primary preheating mechanism and the secondary heat recovery mechanism in some embodiments of this application; Figure 9 This is a schematic diagram of the structure of the primary preheating chamber and the secondary preheating mechanism in some embodiments of this application; Figure 10 This is a schematic diagram of the secondary preheating mechanism and heating mechanism in some embodiments of this application; Figure 11 These are schematic diagrams of the secondary preheating mechanism and cyclone dust collector in some embodiments of this application; Figure 12 This is a schematic diagram of the structure of the drainage plate assembly according to some embodiments of this application.

[0019] in, Figures 1 to 12 The correspondence between the reference numerals and component names in the attached drawings is as follows: 100. Conveying mechanism; 110. Support base; 120. Leg; 130. Conveyor belt; 140. First support frame; 150. Receiving hopper; 200. Primary preheating mechanism; 210. Primary preheating chamber; 220. Gathering frame; 230. Connecting pipe; 240. Cyclone dust collector; 241. Sand discharge pipe; 242. Exhaust pipe; 250. Support block; 300. Primary heat recovery mechanism; 310. Tube rack; 320. Preheating air duct; 330. Diffuser nozzle; 340. Impact nozzle; 400. Secondary heat recovery mechanism; 410. Heat exchange chamber; 420. Heat exchange tube; 421. Exhaust vent; 422. Pipe cover; 430. First fan; 500. Secondary preheating mechanism; 510. Secondary support frame; 520. Secondary preheating chamber; 521. Discharge hopper; 530. Shielding cover; 540. Scraper; 550. Drainage plate assembly; 600. Heating mechanism; 610. Connecting cover; 620. Second fan; 630. Heating rod. Detailed Implementation

[0020] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0022] The following reference Figures 1 to 12 This application describes a heat recovery type feed preheater provided according to some embodiments.

[0023] like Figure 1As shown, the heat recovery type raw material preheater provided according to some embodiments of this application includes a conveying mechanism 100, a preheating mechanism, a heat recovery mechanism, and a heating mechanism 600. The conveying mechanism 100 is assembled at the feed end of a sand dryer and is used to convey wet sand raw materials. The primary preheating mechanism 200 is disposed on the conveying mechanism 100 and includes a semi-enclosed primary preheating chamber 210, which can uniformly preheat the wet sand raw materials conveyed on the conveying mechanism 100. The primary heat recovery mechanism 300 has one end sealed to the exhaust port of the sand dryer and the other end extending to one side of the primary preheating chamber 210 for recovering the exhaust gas emitted by the dryer. The primary heat recovery mechanism 300 includes multiple nozzles evenly distributed along the length of the primary preheating chamber 210 on one side. The exhaust gas from the dryer provides airflow guidance for the sand particles that have been preheated in the primary preheating chamber 210; the secondary heat recovery mechanism 400, connected to the primary preheating mechanism 200, can collect the exhaust gas from the primary preheating chamber 210 to achieve cascade recovery of waste heat; the secondary preheating mechanism 500, located on one side of the transmission mechanism 100 and connected to the secondary heat recovery mechanism 400, is used to preheat the wet sand that has not been blown off from the primary preheating chamber 210 and is still attached, and utilizes the heat energy recovered by the secondary heat recovery mechanism 400; the heating mechanism 600, located on the secondary preheating mechanism 500, is used to provide an additional heat source.

[0024] In this embodiment, wet sand raw material enters the conveying mechanism 100, which starts and transports it at a stable rate. It first enters the semi-enclosed space of the primary preheating chamber 210, simultaneously starting the sand dryer. High-temperature exhaust gas generated during dryer operation is discharged through the exhaust port. The primary heat recovery mechanism 300 collects this exhaust gas, converts it into preheated hot air, and introduces it into the preheating chamber through nozzles evenly distributed along the length of the primary preheating chamber 210. The preheated hot air comes into full contact with the wet sand on the conveying mechanism 100, performing the first uniform preheating of the wet sand, gradually increasing the temperature of the wet sand, reducing the difficulty of subsequent drying, and the directional blowing of the hot air provides airflow guidance for the wet sand, allowing most of the preheated wet sand to flow from the conveying mechanism 100... The material detaches from the conveying mechanism 100 and directly enters the discharge end of the device. After the first preheating is completed, the exhaust gas in the first preheating chamber 210 after passing through the hot water is collected by the secondary heat recovery mechanism 400 and its heat is transferred to the secondary preheating mechanism 500. The conveying mechanism 100 continues to operate, transporting the residual wet sand that has not been blown off its surface to the area of ​​the secondary preheating mechanism 500. The secondary preheating mechanism 500 uses the exhaust gas transferred by the secondary heat recovery mechanism 400 and works in conjunction with the heating mechanism 600 to provide an additional heat source to preheat the residual wet sand a second time, ensuring that the temperature of the residual wet sand meets the standard. After the second preheating is completed, the material enters the discharge end of the device to complete the preheating treatment, and then enters the feed end of the sand dryer for drying and post-processing.

[0025] In some possible embodiments, such as Figure 2As shown, the transmission mechanism 100 includes: a support base 110, which is fixedly mounted on the sand dryer; two legs 120, which are symmetrically mounted on the top of the support base 110; a transmission belt 130, which is rotatably mounted on the two legs 120; a first support frame 140, which is mounted on one side of the top of the transmission belt 130; and a receiving hopper 150, which is fixedly mounted on the first support frame 140, with a gap reserved between the output end of the receiving hopper 150 and the transmission belt 130.

[0026] In this embodiment, wet sand raw material enters through the top feed inlet of the receiving hopper 150. The funnel-shaped receiving hopper 150 buffers and guides the wet sand. The wet sand falls evenly onto the conveyor belt 130 through the bottom of the receiving hopper 150. Since there is a gap between the output end of the receiving hopper 150 and the conveyor belt 130, the wet sand can form a uniform material layer on the conveyor belt 130. The thickness of the material layer is the gap between the output end of the receiving hopper 150 and the conveyor belt 130. The conveyor belt 130 is started to roll synchronously, and the conveyor belt 130 drives the wet sand material layer to run smoothly, passing through the primary preheating chamber 210, the secondary preheating mechanism 500 and other subsequent processing stages in sequence.

[0027] In some possible embodiments, such as Figures 2 to 4 As shown, the primary preheating mechanism 200 includes: a primary preheating chamber 210, which is covered by the conveyor belt 130; a collection frame 220, which is disposed on one side of the primary preheating chamber 210, and a guide groove is provided on the inner wall of the primary preheating chamber 210 near the collection frame 220; a connecting pipe 230, which is disposed at the output end of the collection frame 220; and a cyclone dust collector 240, which is connected to the end of the connecting pipe 230 away from the collection frame 220, and the connecting pipe 230 and the cyclone dust collector 240 are tangentially arranged, and the cyclone dust collector 240 has a funnel-shaped structure. Two support blocks 250 are fixedly mounted on the support base 110, and the cyclone dust collector 240 is mounted and fixed on the two support blocks 250. The cyclone dust collector 240 includes: a sand discharge pipe 241, which is located at the bottom of the funnel-shaped structure of the cyclone dust collector 240; and an exhaust pipe 242, which is coaxially mounted with the sand discharge pipe 241 at the top of the cyclone dust collector 240. The sand discharge pipe 241 extends into the interior of the cyclone dust collector 240, and a uniform annular gap is formed between the outer wall of the sand discharge pipe 241 and the inner wall of the cyclone dust collector 240.

[0028] In this embodiment, the transmission mechanism smoothly drives the wet sand into the semi-enclosed cavity of the primary preheating chamber 210. The wet sand moves at a constant speed with the conveyor belt 130. At this time, the hot air from the primary heat recovery mechanism 300 is continuously introduced into the cavity through evenly distributed nozzles. The hot air fully contacts the wet sand on the conveyor belt 130, uniformly preheating the wet sand, gradually reducing the surface moisture content of the wet sand, and increasing the temperature of the wet sand. After the wet sand reaches the standard temperature after primary preheating, the hot air from the primary heat recovery mechanism 300 continues to blow, pushing the sand particles towards the side of the primary preheating chamber 210 near the collecting frame 220. The sand particles slide into the collecting frame 220 along the guide groove on the inner wall of the primary preheating chamber 210. The funnel-shaped collecting frame 220 causes the dispersed sand particles to quickly converge, forming a stable sand particle flow. The sand particles in the collecting frame 220 enter the connecting pipe 230 through the output end and are transported to the cyclone dust collector 240 along the connecting pipe 230. Because the connecting pipe 230 and the cyclone dust collector 240 are connected... The sand particles are tangentially arranged and enter the funnel-shaped cyclone dust collector 240. They move in a high-speed circular motion with the airflow. Under the action of centrifugal force, the sand particles, due to their higher density, are thrown towards the inner wall of the dust collector and fall down along the inner wall. Meanwhile, the hot air carrying residual heat converges towards the center of the dust collector. The falling sand particles enter the sand discharge pipe 241 at the bottom of the cyclone dust collector 240 and are introduced into the feed pipe of the sand dryer through the sand discharge pipe 241 for subsequent drying. The hot air that converges to the center of the dust collector enters the exhaust pipe 242 at the top through the uniform annular gap between the sand discharge pipe 241 and the inner wall of the dust collector. The exhaust pipe 242 sends the sand to the secondary heat recovery mechanism 400 for subsequent secondary preheating. The transmission mechanism 100 continuously conveys wet sand into the primary preheating chamber 210. The primary heat recovery mechanism 300 continuously introduces residual hot air, and the processes of aggregation and separation are carried out simultaneously to form a stable primary preheating cycle until the wet sand pretreatment is completed.

[0029] In some possible embodiments, such as Figure 4 , Figure 5 As shown, the primary heat recovery mechanism 300 includes: multiple tube supports 310, fixedly installed on the side of the primary preheating chamber 210 away from the gathering frame 220; a preheating air duct 320, installed on the multiple tube supports 310, one end of which is sealed to the waste heat discharge port of the sand dryer, and the other end extends to one side of the primary preheating chamber 210; a diffusion nozzle 330, installed at the end of the preheating air duct 320 near the feed end of the primary preheating chamber 210; and multiple impact nozzles 340, evenly spaced on the preheating air duct 320 and facing the interior of the primary preheating chamber 210.

[0030] In this embodiment, after the sand dryer starts running, the high-temperature hot air generated by burning fuel dries the sand. The exhaust gas after drying is discharged through the exhaust port of the dryer. At this time, the preheating air duct 320 of the primary heat recovery mechanism 300 is precisely connected by a sealed connection to receive the preheating hot air, avoiding energy waste and thermal pollution caused by direct exhaust gas emission. After the preheating hot air enters the preheating air duct 320, it is stably transported along the duct body towards the primary preheating chamber 210. It is diverted at the end of the duct and along the way. The transmission mechanism 100 carries the wet sand into the primary preheating chamber 210, where it first meets the exhaust gas from the diffuser nozzle 330. The wide-range hot air comes into contact with the wet sand, and the hot air quickly spreads and covers the initial layer of wet sand, completing the initial preheating of the wet sand and reducing the surface moisture content of the wet sand. Then the wet sand moves at a constant speed with the conveyor belt 130 and passes through the coverage area of ​​multiple impact nozzles 340 in sequence. The directional hot air discharged from the impact nozzles 340 penetrates the wet sand layer, realizing the deep and uniform preheating of the wet sand and increasing the overall temperature of the wet sand. At the same time, the impact force of the hot air from the impact nozzles 340 continuously pushes the preheated sand particles towards the side of the primary preheating chamber 210 near the collection frame 220. With the help of the guide groove on the inner wall of the preheating chamber, the sand particles are guided into the collection frame 220.

[0031] In this design, the high-temperature waste heat emitted by the dryer can be efficiently recovered by sealing the preheating air duct 320 with the waste heat discharge port of the sand dryer. The exhaust gas that was originally directly emitted is converted into preheating heat energy, which greatly reduces the energy consumption of the preheating process. In addition, the staged hot air layout of the diffuser nozzle 330 and multiple impact nozzles 340 is adopted. The diffuser nozzle 330 realizes wide and uniform preheating in the initial stage of wet sand, and the impact nozzles 340 realize deep penetration preheating throughout the wet sand conveying process. The two work together to ensure that the hot air is in full contact with the wet sand layer. At the same time, the hot air from the impact nozzles 340 can blow away the wet sand stack, further improving the preheating uniformity.

[0032] In some possible embodiments, such as Figures 6 to 8 As shown, the secondary heat recovery mechanism 400 includes: a heat exchange chamber 410 connected to the output end of the exhaust pipe 242; multiple heat exchange tubes 420 arranged in a rectangular array inside the heat exchange chamber 410, each heat exchange tube 420 penetrating the inner cavity of the heat exchange chamber 410; two exhaust ports 421 located on both sides of the heat exchange chamber 410; a pipe cover 422 detachably covering any of the exhaust ports 421; and two first fans 430 respectively located inside each exhaust port 421.

[0033] In this embodiment, during the operation of the primary preheating mechanism 200, the residual hot air separated by the cyclone dust collector 240 is continuously transported to the heat exchange chamber 410 through the exhaust pipe 242. The hot air then enters the enclosed heat exchange space through the air inlet of the heat exchange chamber 410. After entering the heat exchange chamber 410, the residual hot air flows towards the heat exchange tube 420 array area under the suction power of the first fan 430. Since the multiple heat exchange tubes 420 are arranged in a rectangular array, the hot air can evenly pass through the gaps between the tubes and fully contact the outer wall of the heat exchange tubes 420. In this process, the heat energy carried by the hot air is conducted through the pipe wall to the interior of the heat exchange tube 420, realizing the recovery and conversion of residual heat. The airflow inside the heat exchange tube 420 is connected to the secondary preheating mechanism 500. The airflow inside the tube that has absorbed heat energy flows to the secondary preheating mechanism 500 under the action of the fan, and transports the recovered residual preheat to the secondary preheating area to provide energy for the secondary preheating of the residual wet sand on the conveyor belt 130. The low-temperature exhaust gas that has completed the heat exchange is discharged through the exhaust port that is not closed by the pipe cover 422 under the action of the first fan 430.

[0034] In some possible embodiments, such as Figures 9 to 12 As shown, the secondary preheating mechanism 500 includes: a second support frame 510, fixedly mounted on the support base 110; a secondary preheating chamber 520, mounted on the second support frame 510, the inner cavity of the secondary preheating chamber 520 communicating with the inner cavity of each heat exchange tube 420; a shield 530, covering the end of the conveyor belt 130 away from the receiving hopper 150, the inner cavity of the shield 530 communicating with the inner cavity of the primary preheating chamber 210; a scraper 540, mounted on the secondary preheating chamber 520, with the cutting edge of the scraper 540 abutting against the surface of the conveyor belt 130; and a guide plate assembly 550, mounted inside the secondary preheating chamber 520.

[0035] In this embodiment, after the conveying mechanism 100 completes the first preheating of the wet sand, most of the sand particles are pushed down to the collection frame 220 by the hot air from the primary heat recovery mechanism 300. A small amount of sticky or piled-up wet sand remains attached to the surface of the conveyor belt 130. As the conveyor belt 130 continues to run, under the sealed guidance of the shield 530, the residual wet sand enters the opening area of ​​the secondary preheating chamber 520 with the conveyor belt 130. When the conveyor belt 130 carrying the residual wet sand reaches the position of the scraper 540, the blade of the scraper 540, which is in close contact with the surface of the conveyor belt 130, forcibly scrapes off the residual wet sand. The scraped-off wet sand falls into the secondary preheating chamber 520 under the action of gravity. On the flow plate assembly 550, the secondary heat recovery mechanism 400 continuously introduces the recovered residual exhaust gas into the inner cavity of the secondary preheating chamber 520 through the heat exchange pipe 420. The scraped wet sand is evenly dispersed under the guidance of the flow plate assembly 550 and flows slowly along the flow plate. During this process, it comes into full contact with the hot air in the cavity to complete the secondary preheating, further reducing the moisture content of the wet sand and increasing the temperature. After secondary preheating, the sand particles flow to the bottom discharge hopper 521 of the secondary preheating chamber 520 under the guidance of the flow plate assembly 550, and finally enter the feed pipe of the sand dryer through the sand discharge pipe 241, where they merge with the sand particles that have entered the dryer after primary preheating and enter the subsequent drying process together.

[0036] In some possible embodiments, such as Figure 10 , Figure 11 As shown, the heating mechanism 600 includes: a connecting cover 610, one end of which is connected to the heat exchange chamber 410 and the other end of which is connected to the secondary preheating chamber 520, the inner cavity of the connecting cover 610 being connected to the inner cavity of each heat exchange tube 420; a second fan 620, which is disposed inside the connecting cover 610; and a heating rod 630, which is disposed inside the connecting cover 610 and located on the side of the second fan 620 near the secondary preheating chamber 520.

[0037] In this embodiment, when the equipment is operating normally and there is sufficient waste heat, the heating mechanism 600 is in standby mode. The heat exchange tube 420 of the secondary heat recovery mechanism 400 introduces the recovered residual waste heat into the connecting cover 610. The second fan 620 is started, and the waste heat airflow is smoothly pushed to the secondary preheating chamber 520 to provide heat energy for the secondary waste heat of the residual wet sand. At this time, the heating rod 630 is not started, and the waste heat is used first to reduce energy consumption. The temperature sensor monitors the temperature inside the secondary preheating chamber 520 and the temperature of the hot airflow at the outlet of the connecting cover 610 in real time, and transmits the monitoring data to the control system. If the temperature is detected to be lower than the threshold, the heating rod 630 is started to heat. The high temperature heat energy generated by the heating rod 630 is diffused in the connecting cover 610 through the second fan 620 to provide stable heat energy for the residual wet sand, ensuring that the residual wet sand is fully preheated in the secondary preheating chamber 520.

[0038] In some possible embodiments, such as Figure 12As shown, the drainage plate assembly 550 consists of multiple drainage plates, and each drainage plate is inclined.

[0039] In this embodiment, the stepped layout of multiple inclined guide plates disperses the sand particles, increases the contact area and contact time with residual heat, avoids insufficient local residual heat caused by sand particle accumulation, and the scientific adaptation of the inclination angle and gradient design not only avoids the sand particles flowing too fast or too slow, but also prevents the sand particles from getting stuck and accumulating, ensuring stable material conveying efficiency.

[0040] In some possible embodiments, the sand discharge pipe 241 of the cyclone dust collector 240 is connected to the feed pipe of the sand dryer.

[0041] In this embodiment, the sand particles separated by the cyclone dust collector 240 have undergone one preheating, resulting in increased temperature and reduced moisture content. Through the interconnected design, they directly enter the dryer, avoiding temperature drop and moisture absorption caused by contact between the preheated sand particles and the external environment. The sand particles enter the drying stage at a higher temperature, which can significantly shorten the subsequent drying time, reduce the energy consumption of the dryer, and reduce uneven drying and surface clumping caused by excessive temperature differences in the sand particles, thereby improving the drying quality.

[0042] During operation, the heat recovery type raw material preheater receives wet sand through the receiving hopper 150 of the conveying mechanism 100. The funnel-shaped receiving hopper 150 buffers and guides the wet sand, and with the reserved gap between it and the conveyor belt 130, the wet sand is evenly spread on the conveyor belt 130 to form a stable material layer. The conveyor belt 130 starts conveying at a constant speed. The high-temperature waste heat discharged from the sand dryer is received through the preheating air duct 320 of the primary heat recovery mechanism 300. The waste heat hot air is conveyed and distributed along the preheating air duct 320, and the front diffuser nozzle 330 diffuses the hot air wide to initially preheat the wet sand that has just entered the primary preheating chamber 210. Subsequently, multiple evenly distributed jets... The nozzle 340 sprays directional hot air to achieve deep and uniform preheating of the wet sand, and pushes the preheated sand particles towards the collection frame 220 on one side of the primary preheating chamber 210. Under the guidance of the guide groove, the sand particles are collected. The sand particles in the collection frame 220 enter the funnel-shaped cyclone dust collector 240 through the connecting pipe 230. Under the action of centrifugal force, the sand particles are separated from the hot air. The separated sand particles are directly introduced into the feed pipe of the sand dryer through the bottom sand discharge pipe 241 for subsequent drying processes. The hot air carrying residual heat enters the exhaust pipe 242 through the annular gap between the sand discharge pipe 241 and the inner wall of the dust collector, and then enters the heat exchange chamber 410 of the secondary heat recovery mechanism 400. Under the suction of the machine 430, the hot air passes through the rectangular array of heat exchange tubes 420. The heat energy of the hot air is conducted through the tube wall to the interior of the heat exchange tubes 420, completing the secondary recovery and conversion of waste heat. The low-temperature exhaust gas after heat exchange is discharged through the controllable exhaust port 421. The airflow inside the tube that has absorbed heat energy is transported to the secondary preheating mechanism 500. The residual wet sand on the conveyor belt 130 that was not blown off by the primary preheating enters the secondary preheating chamber 520 under the sealed guidance of the shield 530. The blade of the scraper 540 is in close contact with the conveyor belt 130, forcibly scraping the residual wet sand off to the internal guide plate assembly 550. The waste heat conducted by the secondary heat recovery mechanism 400 is continuously introduced into the secondary preheating chamber 520, and the scraped wet sand... Under the guidance of multiple inclined diversion plates, the sand is evenly dispersed and flows slowly, fully contacting the residual heat to complete the secondary preheating. The preheated sand particles are guided by the diversion plates and introduced into the feed pipe of the sand dryer from the sand discharge pipe 241, where they merge with the sand particles preheated in the first stage. Temperature sensors monitor the outlet temperature of the secondary preheating chamber 520 and the connecting cover 610 in real time. When the residual heat is insufficient and the temperature is lower than the threshold, the heating rod 630 of the heating mechanism 600 is activated. The high-temperature heat energy generated is mixed with the residual heat airflow under the action of the second fan 620 to form a stable and qualified hot airflow that is sent into the secondary preheating chamber 520 to ensure the preheating effect. When the residual heat is sufficient, the heating rod 630 is on standby, giving priority to the use of residual heat for energy saving.

[0043] In this application, it should be noted that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] In this application, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. The term "multiple" refers to two or more, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0046] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0047] In this application, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0048] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A heat recovery type raw material preheater, characterized in that, include: The conveying mechanism, assembled at the feed end of the sand dryer, is used to convey wet sand raw materials; A primary preheating mechanism is provided on the conveying mechanism, including a semi-enclosed primary preheating chamber, which can uniformly preheat the wet sand raw material conveyed on the conveying mechanism in one step. The primary heat recovery mechanism has one end sealed to the exhaust port of the sand dryer and the other end extending to one side of the primary preheating chamber. It is used to recover the exhaust gas emitted by the dryer. The primary heat recovery mechanism includes multiple nozzles that are evenly distributed on one side of the primary preheating chamber along its length. It uses the exhaust gas of the dryer to provide wind guidance for the sand particles that have been preheated in the primary preheating chamber. The secondary heat recovery mechanism is connected to the primary preheating mechanism and can collect the exhaust gas from the primary preheating chamber to achieve cascade recovery of waste heat. A secondary preheating mechanism is located on one side of the transmission mechanism and connected to the secondary heat recovery mechanism. It is used to preheat the wet sand that was not blown off and was still attached in the primary preheating chamber, and to recover the heat energy using the secondary heat recovery mechanism. A heating mechanism, mounted on the secondary preheating mechanism, is used to provide an additional heat source.

2. The heat recovery type raw material preheater according to claim 1, characterized in that, The transmission mechanism includes: The support base is fixedly installed on the sand dryer; Two legs are symmetrically arranged on top of the support base; The conveyor belt is rotatably mounted on the two aforementioned legs; The first support frame is disposed on one side of the top of the conveyor belt; A receiving hopper is fixedly mounted on the first support frame, and a gap is reserved between the output end of the receiving hopper and the conveyor belt.

3. The heat recovery type raw material preheater according to claim 2, characterized in that, The primary preheating mechanism includes: A primary preheating chamber is installed over the conveyor belt; An aggregation frame is disposed on one side of the primary preheating chamber, and a guide groove is provided on the inner wall of the primary preheating chamber near the aggregation frame; A connecting pipe is installed at the output end of the aggregation frame; A cyclone dust collector is connected to the end of the connecting pipe away from the collecting frame, and the connecting pipe is tangential to the cyclone dust collector, which has a funnel-shaped structure. Two support blocks are fixedly installed on the support base, and the cyclone dust collector is erected and fixed on the two support blocks.

4. The heat recovery type raw material preheater according to claim 3, characterized in that, The cyclone dust collector includes: A sand discharge pipe is installed at the bottom of the funnel-shaped structure of the cyclone dust collector; An exhaust pipe is coaxially arranged at the top of the cyclone dust collector with the sand discharge pipe. The sand discharge pipe extends into the interior of the cyclone dust collector, and a uniform annular gap is formed between the outer wall of the sand discharge pipe and the inner wall of the cyclone dust collector.

5. The heat recovery type raw material preheater according to claim 3, characterized in that, The primary heat recovery mechanism includes: Multiple tube racks are fixedly installed on the side of the primary preheating chamber away from the aggregation frame; A preheating air duct is installed on multiple pipe racks, with one end sealed to the waste heat discharge port of the sand dryer and the other end extending to one side of the primary preheating chamber. A diffusion nozzle is disposed at one end of the preheating air duct near the feed end of the primary preheating chamber; Multiple impact nozzles are evenly spaced on the preheating air duct and face the interior of the primary preheating chamber.

6. The heat recovery type raw material preheater according to claim 3, characterized in that, The secondary heat recovery mechanism includes: The heat exchange chamber is connected to the outlet end of the exhaust pipe; Multiple heat exchange tubes are arranged in a rectangular array inside the heat exchange chamber, and each heat exchange tube penetrates the inner cavity of the heat exchange chamber. Two exhaust vents are located on both sides of the heat exchange chamber; A pipe cover, which can be detachably fitted onto any of the aforementioned exhaust vents; Two primary fans are respectively installed inside each of the aforementioned exhaust vents.

7. The heat recovery type raw material preheater according to claim 6, characterized in that, The secondary preheating mechanism includes: The second support frame is fixedly mounted on the support base; A secondary preheating chamber is installed on the second support frame, and the inner cavity of the secondary preheating chamber is connected to the inner cavity of each heat exchange tube. A shield is provided on the end of the conveyor belt away from the receiving hopper, and the inner cavity of the shield is in communication with the inner cavity of the primary preheating chamber; A scraper is disposed on the secondary preheating chamber, and the cutting edge of the scraper abuts against the surface of the conveyor belt; The diversion plate assembly is installed inside the secondary preheating chamber.

8. The heat recovery type raw material preheater according to claim 7, characterized in that, The heating mechanism includes: The connecting cover is connected at one end to the heat exchange chamber and at the other end to the secondary preheating chamber. The inner cavity of the connecting cover is connected to the inner cavity of each heat exchange tube. The second fan is located inside the connecting cover; The heating rod is disposed inside the connecting cover and located on the side of the second fan near the secondary preheating chamber.

9. The heat recovery type raw material preheater according to claim 7, characterized in that, The drainage plate group consists of multiple drainage plates, and each drainage plate is inclined.

10. The heat recovery type raw material preheater according to claim 4, characterized in that, The sand discharge pipe of the cyclone dust collector is connected to the feed pipe of the sand dryer.

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