A drying device and drying method for sodium pyrophosphate production

Abstract

The present invention discloses a drying device and drying method for sodium pyrophosphate production, which relates to the technical field of material drying, and includes a frame, a heating bin, a rotating shaft, and several paddle assemblies, wherein the heating bin is mounted on the frame, the rotating shaft is inserted into the heating bin and rotates with the heating bin, the rotating shaft is a hollow structure with an opening at one end, the other end of the rotating shaft is connected with a driving assembly, the paddle assemblies are staggered and inserted on the rotating shaft, the paddle assemblies include a through pipe and a scraper, the scraper is fixed at one end of the through pipe and fits the curvature of the inner wall of the heating bin, and is used to scrape off the material attached to the inner wall of the heating bin, the through pipe is a hollow pipe and extends into the opening at one end of the rotating shaft, the through pipe is provided with several pores on its circumference, and a screen is provided at the pores to prevent the material from entering. The present invention can effectively avoid the thermal decomposition caused by the internal heat accumulation of the block material, and improve the purity of the finished product.

Description

Technical Field

[0001] The invention relates to the technical field of material drying, in particular to a drying device and a drying method for sodium pyrophosphate production. Background Art

[0002] Sodium pyrophosphate, also known as tetrasodium diphosphate, is an important inorganic compound that is widely used in many fields, including detergents, food additives, water treatment, etc. It has emulsifying and dispersing properties, can prevent fat oxidation, improve protein binding, and inhibit food oxidation and fermentation at high pH values. In the production process, drying is a key step to ensure product quality and safety.

[0003] The drying process of sodium pyrophosphate usually includes the following steps: Dissolution: Mix sodium pyrophosphate and water in a certain proportion to dissolve. Reaction: Some chemical reactions may be carried out as needed, such as adding other compounds for neutralization or polymerization. Filtration: Remove insoluble impurities. Concentration: Remove part of the water by evaporation or other methods. Drying: Use drying equipment to remove most of the water to obtain dry sodium pyrophosphate. Crushing and screening: The dried sodium pyrophosphate may need further crushing and screening to obtain the desired particle size.

[0004] As can be seen from the above, sodium pyrophosphate needs to go through two drying steps, from solution to a small amount of liquid and then to completely dried solid powder. The existing equipment for drying sodium pyrophosphate is mainly conventional paddle dryers, which can break up the dried material during the drying process to improve the drying effect. The drying of sodium pyrophosphate focuses on heat control. Although it can be stirred by paddles, a large amount of heat will still accumulate at the bottom due to gravity. If it continues in the high-temperature drying process, sodium pyrophosphate may undergo thermal decomposition, reducing the purity of the finished product. Summary of the invention

[0005] The object of the present invention is to provide a drying device and a drying method for producing sodium pyrophosphate to solve the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a drying device for sodium pyrophosphate production, comprising a frame, a heating bin, a rotating shaft and a plurality of paddle assemblies, wherein the heating bin is mounted on the frame, the rotating shaft is passed through the heating bin and rotatably cooperates with the heating bin, the rotating shaft is a hollow structure with an opening at one end, a driving assembly is connected to the other end of the rotating shaft, and the paddle assemblies are staggered and passed through the rotating shaft.

[0007] According to the above technical solution, the paddle assembly includes a through pipe and a scraper. The scraper is fixed at one end of the through pipe and fits the curvature of the inner wall of the heating bin, and is used to scrape off the material attached to the inner wall of the heating bin. The through pipe is a hollow tube and extends into the opening at one end of the rotating shaft. A plurality of air holes are opened around the circumference of the through pipe, and a screen is provided at the air holes to prevent the material from entering.

[0008] According to the above technical solution, the open end of the rotating shaft is connected to a gas input device, and the gas input device is connected to a heat-insulating gas box.

[0009] According to the above technical solution, a paddle is sleeved on the through pipe, and the paddle includes a ring on both sides, two blades and two baffles, wherein the ring is respectively connected to the scraper and the rotating shaft with a spring, the two blades are respectively connected to the ring and are arranged at 180 degrees, the baffle is connected to the corresponding blade and the inner wall is arranged to fit the curvature of the through pipe.

[0010] According to the above technical solution, the cross section of the blade is an isosceles triangle structure, and the opposite ends of the two baffles exceed the range covered by the blade to cover part of the pores.

[0011] According to the above technical solution, two air outlet pipes are provided on the heating bin, the air outlet pipes are connected to the thermal insulation air box, and a barrier net is provided inside the air outlet pipe to isolate the internal material.

[0012] According to the above technical scheme, an adsorption layer one, an adsorption layer two, an electric push rod one and an electric push rod two are arranged in the thermal insulation air box, wherein the adsorption layer one is arranged perpendicularly to the adsorption layer two, the adsorption layer two is arranged at the air outlet of the thermal insulation air box, the driving end of the electric push rod one is connected to a push plate one, the surface of the push plate one is arranged parallel to the adsorption layer one, an air cavity is opened in the push plate one, the air cavity and the surface of the push plate one are connected to a plurality of air ports, the air cavity is connected to the air outlet pipe, the driving end of the electric push rod two is connected to a push plate two, the surface of the push plate two is arranged parallel to the adsorption layer two.

[0013] According to the above technical solution, a feed pipe is provided on the upper side of the heating bin, the feed pipe is connected to a mixing box, a flow valve is provided between the feed pipe and the mixing box, and the mixing box is used to mix and store a mixed solution of sodium pyrophosphate and other compounds.

[0014] According to the above technical solution, a filter plate is slidably arranged in the feed pipe, a connecting groove is opened on the inner wall of the feed pipe, an elastic rope is connected to the filter plate and the top of the connecting groove, and a pressure sensing module is laid on the top of the connecting groove.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention, by providing a paddle assembly, wherein the hollow rotating shaft and the through-tube are provided, can deliver dry airflow into the heating bin, and blow away the bulk material on the basis of being able to turn the material over, thereby avoiding the situation where heat accumulation causes thermal decomposition and improving the purity of the finished product; by providing a deflectable blade, most of the airflow can be distributed to the heavier side of the material, and the limited airflow can be effectively utilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 is a partial cross-sectional view of the present invention;

[0019] Figure 3 It is a partial schematic diagram of the present invention;

[0020] Figure 4 is a schematic diagram of a blade assembly of the present invention;

[0021] Figure 5 is a schematic diagram of the initial state of the blade assembly of the present invention rotating upward;

[0022] Figure 6 is a schematic diagram of the blade assembly of the present invention in an upward rotating state;

[0023] Figure 7 is a schematic diagram of the initial state of the blade assembly of the present invention rotating downward;

[0024] Figure 8 is a schematic diagram of the blade assembly of the present invention in a downward rotating state;

[0025] Fig. 9 is a schematic diagram of a heat-insulating air box of the present invention;

[0026] Fig.10 The present invention Figure 1 A magnified schematic diagram of area A;

[0027] Fig.11 The present invention Figure 2 A magnified schematic diagram of area B;

[0028] In the figure: 1. frame; 2. heating chamber; 21. air outlet pipe; 22. feed pipe; 221. filter plate; 222. connecting groove; 223. elastic rope; 3. rotating shaft; 31. driving assembly; 4. paddle assembly; 41. through pipe; 411. air hole; 412. screen; 42. scraper; 43. paddle; 431. collar; 432; blade; 433. baffle; 44. spring; 5. gas input device; 6. heat preservation gas box; 61. adsorption layer 1; 62. adsorption layer 2; 63. electric push rod 1; 64. electric push rod 2; 65. push plate 1; 651. air cavity; 652. air port; 7. mixing box; 8. flow valve. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] See also Figure 1-11 The present invention provides a technical solution: a drying device for sodium pyrophosphate production, comprising a frame 1, a heating bin 2, a rotating shaft 3 and a plurality of paddle assemblies 4, wherein the heating bin 2 is mounted on the frame 1, the rotating shaft 3 is inserted into the heating bin 2 and rotates with the heating bin 2, the rotating shaft 3 is a hollow structure with an opening at one end, the other end of the rotating shaft 3 is connected to a driving assembly 31, and the paddle assemblies 4 are staggered and inserted on the rotating shaft 3;

[0031] The blade assembly 4 includes a through pipe 41 and a scraper 42. The scraper 42 is fixed to one end of the through pipe 41 and fits the curvature of the inner wall of the heating bin 2 to scrape off the material attached to the inner wall of the heating bin 2. The through pipe 41 is a hollow pipe and extends into the opening of one end of the rotating shaft 3. The through pipe 41 is provided with a plurality of air holes 411 on its circumference. A screen 412 is provided at the air holes 411 to prevent the material from entering.

[0032] The open end of the rotating shaft 3 is connected to a gas input device 5 , and the gas input device 5 is connected to a heat-insulating gas box 6 .

[0033] In one embodiment, the gas input device 5 adopts an air pump, and the inner wall of the thermal insulation gas box 6 adopts thermal insulation material to keep the gas temperature within a suitable temperature and humidity range. The driving component 31 is preferably but not limited to a motor pulley combination to control the rotation of the rotating shaft 3.

[0034] In actual operation, the heating bin 2 heats the internal material normally, the gas input device 5 transports the gas in the heat-insulating gas box 6 to the rotating shaft 3, and the gas is ejected from the air holes 411 through the through pipes 41, thereby having the effect of blowing away the material, which can effectively avoid the heat accumulation inside the agglomerated material.

[0035] like Figure 4 As shown, a paddle 43 is sleeved on the through pipe 41, and the paddle 43 includes a collar 431 on both sides, two blades 432 and two baffles 433, wherein the collar 431 is respectively connected to the scraper 42 and the rotating shaft 3 with a spring 44, the two blades 432 are respectively connected to the collar 431 and are arranged at 180 degrees, and the baffle 433 is connected to the corresponding blade 432 and the inner wall is arranged to fit the curvature of the through pipe 41.

[0036] Furthermore, the cross section of the blade 432 is an isosceles triangle structure, and opposite ends of the two baffles 433 exceed the range covered by the blade 432 to shield part of the air hole 411 .

[0037] The supplementary explanation based on the above structure is as follows: Figures 5 to 8 As shown, when the paddle assembly 4 stirs the material, it includes two processes of upward rotation and downward rotation. The upward rotation is set as the initial state. At this time, the two baffles 433 exceed one end of the blade 432 and face downward. The upper surface of the blade 432 is the material accumulation position. If the material accumulated on one side of the blade 432 is heavier than the blade 432 on the other side, the corresponding blade 432 will deflect downward. Under the tension of the spring 44 and the length limit of the spring 44, the deflection angle of the blade 432 is certain and will not exceed the limit range. The limit angle is set manually. The blade 432 with a lighter load is lifted up. At this time, the air hole 41 on the side of the blade 432 with a larger load is facing the air hole 41 on the side of the blade 432 with a larger load. The number of exposed air holes 411 is greater than that on the side of the blade 432 with a lighter load, so that more airflow is distributed to the side with more materials, which can reasonably and effectively distribute the limited airflow. At the same time, because the bulk materials are easy to clump and have heavy weight, this method can more easily capture the bulk materials and blow them away; similarly, when the paddle assembly 4 rotates downward, at this time, the two baffles 433 exceed one end of the blade 432 and face upward, and the length of the area between the two baffles 433 is constant. When the blade 432 deflects, the area between the two baffles 433 deflects toward the side with heavier materials, so that more airflow is distributed to the side with more materials.

[0038] Furthermore, the heating chamber 2 is provided with two air outlet pipes 21, which are connected to the heat preservation air box 6, and a barrier net is provided inside the air outlet pipe 21 to isolate the internal materials.

[0039] like Fig. 9As shown, an adsorption layer 1 61, an adsorption layer 2 62, an electric push rod 1 63 and an electric push rod 2 64 are arranged in the thermal insulation air box 6, wherein the adsorption layer 1 61 is vertically arranged with the adsorption layer 2 62, the adsorption layer 2 62 is arranged at the air outlet of the thermal insulation air box 6, the driving end of the electric push rod 1 63 is connected with a push plate 1 65, the surface of the push plate 1 65 is arranged parallel to the adsorption layer 1 61, an air cavity 651 is opened in the push plate 1 65, the air cavity 651 and the surface of the push plate 1 65 are connected with a plurality of air ports 652, the air cavity 651 is connected to the air outlet pipe 21, the driving end of the electric push rod 2 64 is connected with a push plate 2 66, the surface of the push plate 2 66 is arranged parallel to the adsorption layer 2 62.

[0040] In one embodiment, the adsorption layer 1 61 and the adsorption layer 2 62 are filled with desiccants such as silica gel, molecular sieves or activated carbon to adsorb water vapor. These substances have a strong adsorption capacity for water vapor and can effectively reduce the water vapor content. After the gas input device 5 delivers gas to the heating bin 2, the gas will absorb heat and take away water vapor while achieving the effect of breaking up the block material. When it reaches the heat preservation air box 6, the electric push rod 1 63 pushes the gas to the adsorption layer 1 61. After the gas passes through the adsorption layer 1 61 and filters out part of the water vapor, it is pushed into the space where the adsorption layer 2 62 and the electric push rod 2 64 are located. Then the electric push rod 2 64 pushes the gas to the adsorption layer 2 62. After the gas is dehumidified twice, it is output from the heat preservation air box 6 and re-pumped to the heating bin 2 for circulation. In this way, the gas temperature can be kept as unchanged as possible, and the water vapor content in the gas can be reduced by pressurization and adsorption. That is, when the pressure increases, the water content in the air will decrease. This is because at the same temperature, the saturated vapor pressure of water is fixed. The increase in total pressure will cause the originally saturated water vapor to condense as the partial pressure increases, thereby reducing the content of gaseous water. The water vapor content in the gas is further reduced through the adsorption effect of adsorption layer 1 61 and adsorption layer 2 62.

[0041] A feed pipe 22 is provided on the upper side of the heating bin 2, the feed pipe 22 is connected to a mixing box 7, a flow valve 8 is provided between the feed pipe 22 and the mixing box 7, and the mixing box 7 is used to mix and store a mixed solution of sodium pyrophosphate and other compounds.

[0042] like Figures 10-11 As shown, a filter plate 221 is slidably arranged in the feed pipe 22 , a connecting groove 222 is opened on the inner wall of the feed pipe 22 , an elastic rope 223 is connected to the filter plate 221 and the top of the connecting groove 222 , and a pressure sensing module is laid on the top of the connecting groove 222 .

[0043] In actual operation, the flow valve 8 quantitatively delivers the mixed solution to the heating chamber 2 in batches, and the mixed solution passes through the filter plate 221, the filter plate 221 is pulled down, and the water-insoluble impurities in the mixed solution are filtered out. After the mixed solution is input once, the filter plate 221 is pulled back by the elastic rope 223. Under the action of the rebound force, the impurities blocked in the filter holes of the filter plate 221 will be shaken off, thereby achieving the effect of clearing the filter plate 221.

[0044] The specific implementation is as follows:

[0045] Step 1: Feeding, the filtered mixed solution is input into the heating chamber 2;

[0046] Step 2: Concentration: heating the heating chamber 2 to keep the internal temperature within a set temperature range and evaporate part of the water vapor contained in the internal mixed solution;

[0047] Step 3: Drying, the heating chamber 2 adjusts the heating temperature to thoroughly dry the remaining material, during which the paddle assembly 4 cooperates to turn the material over, and assists the jet air flow to break up the bulk material, thereby avoiding heat accumulation and accelerating the drying process;

[0048] Step 4: Discharging.

[0049] Specifically, in step one, the pressure sensing module can determine whether the filter plate 221 needs to be cleaned according to the response of the pressure signal, that is, taking the first batch of injected mixed solution as a comparison, the mixed solution is set to be in a uniformly mixed state. When the mixed solution is injected, the pressure sensing module detects an increasing pressure signal. After the injection is completed, the pressure signal becomes smaller. This is used as a node to determine the time required for the injection of the mixed solution. If there are too many impurities accumulated on the surface of the filter plate 221, the time required will gradually increase in subsequent injection batches. A critical point is set artificially. When the pressure signal change span exceeds this critical point, the surface of the filter plate 221 needs to be cleaned.

[0050] In step 2, the water vapor produced when the mixed solution is concentrated is transported to the heat-insulating gas box 6 through the outlet pipe 21, and the water vapor is adsorbed and filtered after passing through the adsorption layer 1 61 and the adsorption layer 2 62, and then the dry gas is transported back to the heating chamber 2 to take away the evaporated water vapor again. Because the temperature of the gas itself will not change significantly, the gas will not have a significant impact on the internal temperature after returning to the heating chamber 2. At the same time, because the water vapor is taken away in time, the water vapor saturation in the heating chamber 2 will always be within an ideal range, and the produced water vapor can be continuously absorbed, further accelerating the concentration process.

[0051] In step three, the state of the internal material can be roughly judged by the deflection state of the blade 432, that is, a pressure detection module is added at the connection of the spring 44. If the internal material is completely dry, the material is in a dry powder state and will not adhere to the surface of the blade 432 in blocks, and the material in the loose powder state is distributed more evenly, so there will be no large deviation in the load-bearing of the two blades 432. By detecting the tension of the blade 432, an ideal tension range is set. When the material is completely dry, the pressure detection module should be able to detect a signal segment with an opposite direction but a tension value in the ideal range.

[0052] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0053] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A drying device for sodium pyrophosphate production, comprising a frame (1), a heating chamber (2), a rotating shaft (3) and a plurality of paddle assemblies (4), characterized in that: The heating chamber (2) is mounted on the frame (1), the rotating shaft (3) is inserted into the heating chamber (2) and rotatably cooperates with the heating chamber (2), the rotating shaft (3) is a hollow structure with an opening at one end, the other end of the rotating shaft (3) is connected to a driving assembly (31), and the paddle assembly (4) is staggered and inserted on the rotating shaft (3); The paddle assembly (4) comprises a through pipe (41) and a scraper (42); the scraper (42) is fixed to one end of the through pipe (41) and fits the arc of the inner wall of the heating bin (2) to scrape off materials attached to the inner wall of the heating bin (2); the through pipe (41) is a hollow pipe and extends into the opening of one end of the rotating shaft (3); a plurality of air holes (411) are formed on the circumference of the through pipe (41); a screen (412) is provided at the air hole (411) to prevent materials from entering; The open end of the rotating shaft (3) is connected to a gas input device (5), and the gas input device (5) is connected to a heat-insulating gas box (6); The through pipe (41) is sleeved with a paddle (43), the paddle (43) comprising collars (431) on both sides, two blades (432) and two baffles (433), wherein the collars (431) are respectively connected to the scraper (42) and the rotating shaft (3) with a spring (44), the two blades (432) are respectively connected to the collars (431) and the blades (432) are arranged at 180 degrees to each other, and the baffles (433) are connected to the corresponding blades (432) and the inner walls thereof are arranged to fit the arc of the through pipe (41); The blade (432) has an isosceles triangle structure in cross section, and opposite ends of the two baffles (433) exceed the range covered by the blade (432) and are used to cover part of the air hole (411).

2. A drying device for sodium pyrophosphate production according to claim 1, characterized in that: The inner wall of the heat-insulating gas box (6) is made of heat-insulating material, which is used to keep the gas temperature within a suitable temperature and humidity range.

3. A drying device for sodium pyrophosphate production according to claim 2, characterized in that: When the paddle assembly (4) stirs the material, it includes two processes, namely, upward rotation and downward rotation. The upward rotation is set as the initial state. At this time, the two baffles (433) exceed one end of the blade (432) and face downward. The upper surface of the blade (432) is the material accumulation position. If the material accumulated on one side of the blade (432) is heavier than the other side of the blade (432), the corresponding blade (432) deflects downward. Due to the tension of the spring (44) and the length of the spring (44), the deflection angle of the blade (432) is constant and will not exceed the limit range. The limit angle is set manually. The blade (432) is lifted up, and the number of air holes (411) exposed on the side of the blade (432) with a larger load is greater than that on the side of the blade (432) with a lighter load, so that more airflow is distributed to the side with more material. Similarly, when the paddle assembly (4) rotates downward, the two baffles (433) are upward over one end of the blade (432), and the length of the area between the two baffles (433) is constant. When the blade (432) is deflected, the area between the two baffles (433) is deflected toward the side with heavier material, so that more airflow is distributed to the side with more material.

4. A drying device for sodium pyrophosphate production according to claim 3, characterized in that: The heating chamber (2) is provided with two air outlet pipes (21), the air outlet pipes (21) are connected to the heat-insulating air box (6), and a barrier net is provided inside the air outlet pipes (21).

5. A drying device for sodium pyrophosphate production according to claim 4, characterized in that: The heat-insulating air box (6) is provided with an adsorption layer 1 (61), an adsorption layer 2 (62), an electric push rod 1 (63) and an electric push rod 2 (64), wherein the adsorption layer 1 (61) is arranged perpendicularly to the adsorption layer 2 (62), the adsorption layer 2 (62) is arranged at the air outlet of the heat-insulating air box (6), the driving end of the electric push rod 1 (63) is connected to a push plate 1 (65), the surface of the push plate 1 (65) is arranged parallel to the adsorption layer 1 (61), an air cavity (651) is opened in the push plate 1 (65), the air cavity (651) and the surface of the push plate 1 (65) are connected to a plurality of air ports (652), the air cavity (651) is connected to the air outlet pipe (21), the driving end of the electric push rod 2 (64) is connected to a push plate 2 (66), the surface of the push plate 2 (66) is arranged parallel to the adsorption layer 2 (62).

6. A drying method for a drying device for sodium pyrophosphate production, applicable to the drying device for sodium pyrophosphate production according to claim 5, characterized in that: Step 1: Feeding the material, the filtered mixed solution is input into the heating chamber (2); Step 2: Concentration, heating the heating chamber (2) to keep the internal temperature within a set temperature range, and evaporating part of the water vapor contained in the internal mixed solution; Step 3: Drying: the heating chamber (2) adjusts the heating temperature to thoroughly dry the remaining material. During this period, the paddle assembly (4) cooperates to turn the material and assists the jet air flow to break up the lumps of material, thereby avoiding heat accumulation and accelerating the drying process. Step 4: Discharging.

7. The drying method of a drying device for sodium pyrophosphate production according to claim 6, characterized in that: In step one, the pressure sensing module can determine whether the filter plate (221) needs to be cleaned according to the response of the pressure signal, that is, taking the first batch of injected mixed solution as a comparison, the mixed solution is set to be in a uniformly mixed state. When the mixed solution is injected, the pressure sensing module detects an increasing pressure signal. After the injection is completed, the pressure signal decreases. This is used as a node to determine the time required for the injection of the mixed solution. If too much impurities are accumulated on the surface of the filter plate (221), the time required will gradually increase in subsequent injection batches. A critical point is artificially set. When the pressure signal change span exceeds this critical point, the surface of the filter plate (221) needs to be cleaned.

8. The drying method of a drying device for sodium pyrophosphate production according to claim 7, characterized in that: In step three, a pressure detection module is added at the connection of the spring (44) to judge the state of the internal material through the magnitude and direction of the pulling force generated when the blade (432) is deflected.

Images