Solid color-changing scale scavenger as well as preparation method and preparation equipment thereof

Abstract

The invention relates to the technical field of water treatment, and discloses a solid color-changing scale remover which comprises a core layer and an outer layer, the core layer is wrapped in the outer layer, and the core layer is prepared from the following formula components in percentage by mass: 60%-75% of an acid scale remover, 4%-7% of a corrosion inhibitor, 0.5%-1% of a color-changing indicator, 15%-23% of an excipient and 2%-3% of a surfactant. The preparation method comprises the steps of raw material pretreatment, gradient mixing, wet granulation and double-layer tabletting. The preparation equipment comprises tabletting equipment, the tabletting equipment comprises a feeding device, and the feeding device comprises an outer feeding pipe, an inner feeding pipe, an outer opening and closing mechanism and an inner opening and closing mechanism. The invention provides a solid color-changing water scale scavenger as well as a preparation method and preparation equipment thereof, which can solve or at least alleviate the problems of poor detection limit, color difference, stability and anti-interference performance of the existing color-changing water scale scavenger.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and particularly relates to a solid color-changing scale remover, a preparation method thereof, and a preparation device thereof. Background Art

[0002] Due to the presence of calcium and magnesium ions and other impurities in tap water, after long-term use, a relatively thick layer of scale will form on the inner surface of metal devices or pipelines. Especially in some areas with relatively high water quality hardness, the concentration of calcium and magnesium ions will be higher. Scale has a very serious impact on industrial production, especially for pipelines, boilers, and heat exchangers that transport water. Scale will hinder heat conduction and greatly reduce the thermal efficiency, and also affect the quality of the produced distilled water. At the same time, the presence of a large amount of scale may also cause local overheating of the equipment during the heating process, resulting in damage to the device. Therefore, effectively removing scale in life and production has always been a problem faced by people.

[0003] There are a variety of existing scale removers, but most of them only have the function of removing scale. It is difficult for users to intuitively judge the scale removal process during use, and they often have to rely on experience or set fixed soaking and cleaning times, which easily leads to incomplete scale removal or over-cleaning. The former affects the scale removal effect, and the latter may cause certain damage to the equipment to be cleaned. In addition, in some large-scale industrial cleaning scenarios, operators need to monitor the scale removal conditions of multiple devices at the same time, and traditional non-indicating scale removers cannot meet the requirements of efficient and convenient monitoring. Therefore, developing a scale remover that can intuitively display the scale removal process has important practical significance.

[0004] The invention patent with the publication number CN110982644A discloses a citric acid color-changing scale cleaning agent, a preparation method thereof, and an application. The cleaning agent includes the following components in mass concentration: organic acid 15 - 25%, ammonium salt 1.6 - 2.0%, ethylenediaminetetraacetate 0.03 - 0.05%, surfactant 0.003 - 0.005%, corrosion inhibitor 0.4 - 0.7%, indicator 0.00003 - 0.00005%. This cleaning agent is used to remove scale from boilers, cooling towers, or circulating water pipelines. When the active ingredients of the cleaning agent are consumed, the cleaning agent will change from orange to purple to indicate the failure of the cleaning agent. Compared with the prior art, the present invention has the advantages of small corrosion to equipment, strong cleaning ability, safety and environmental friendliness, and low maintenance cost. However, it is a liquid scale remover, with a large volume, inconvenient for transportation and use, and its indicator has not been modified, and its detection limit, color difference, stability, and anti-interference performance are poor. Summary of the Invention

[0005] The object of the present invention is to overcome the deficiencies in the prior art, solve or at least mitigate the problems of poor detection limit, color difference, stability and anti-interference performance of the existing discoloring scale remover, and provide a solid discoloring scale remover, its preparation method and preparation equipment.

[0006] To achieve the above object, the present invention provides the following technical solution: A solid discoloring scale remover, comprising a core layer and an outer layer, the core layer is wrapped in the outer layer, and the core layer is composed of the following formula components by mass percentage:

[0007] Acidic scale remover 60%-75%, corrosion inhibitor 4%-7%, discoloring indicator 0.5%-1%, excipient 15%-23% and surfactant 2%-3%;

[0008] Among them, the discoloring indicator is a modified bromocresol green-phenol red complex, and the modification of the bromocresol green-phenol red complex is one or a combination of two of hydroxypropyl-β-cyclodextrin embedding and nitro modification.

[0009] To further implement the present invention, the following technical solutions can be preferably selected:

[0010] Preferably, the acidic scale remover is glycolic acid and sulfamic acid, and the mass ratio of glycolic acid to sulfamic acid is 3:1;

[0011] The corrosion inhibitor is ethylenediaminetetramethylenephosphonic acid and benzotriazole, and the mass ratio of ethylenediaminetetramethylenephosphonic acid to benzotriazole is 3:1;

[0012] The excipient is microcrystalline cellulose and polyethylene glycol 6000, and the mass ratio of microcrystalline cellulose to polyethylene glycol 6000 is 2:1;

[0013] The surfactant is sodium dodecylbenzenesulfonate.

[0014] Preferably, the hydroxypropyl-β-cyclodextrin embedding process includes the following steps:

[0015] Sa. Solution preparation, dissolving the bromocresol green-phenol red complex in ethanol to obtain a bromocresol green-phenol red ethanol solution, and dissolving hydroxypropyl-β-cyclodextrin in deionized water to obtain a hydroxypropyl-β-cyclodextrin aqueous solution;

[0016] Sb. Embedding reaction, slowly dropping the bromocresol green-phenol red ethanol solution into the hydroxypropyl-β-cyclodextrin aqueous solution, and after the dropping is completed, continue to stir and react for 4 hours;

[0017] Sc. Solvent removal, evaporating under reduced pressure at 40°C to remove ethanol and part of the water, pre-freezing to -40°C, and then vacuum drying for 24 hours to obtain the embedded product;

[0018] Sd, Purification: Dissolve the embedded product in deionized water and filter to remove unembedded bromocresol green - phenol red.

[0019] Preferably, the nitro - modification process includes the following steps:

[0020] SA, Nitration reaction: In an ice - water bath, dissolve the bromocresol green - phenol red complex in concentrated sulfuric acid, stir until completely dissolved, slowly add concentrated nitric acid dropwise, and continue stirring for 2 hours after the addition is complete.

[0021] SB, Post - treatment: Slowly pour the reaction solution into ice water, precipitate yellow solid, filter the precipitate, wash it with cold water until neutral, and vacuum dry to obtain the nitro - modified bromocresol green - phenol red complex.

[0022] SC, Purification: Recrystallize using an ethanol - water mixed solvent to remove unreacted raw materials and by - products.

[0023] When the bromocresol green - phenol red complex is simultaneously subjected to hydroxypropyl - β - cyclodextrin embedding and nitro - modification, nitro - modification is carried out first, and then hydroxypropyl - β - cyclodextrin embedding.

[0024] Preferably, the color - changing indicator further includes diphenylcarbazide, and the mass ratio of diphenylcarbazide to the bromocresol green - phenol red complex is 1:1 - 1:10.

[0025] A preparation method of a solid color - changing scale remover, which is used to prepare a solid color - changing scale remover, and the preparation method includes the following steps:

[0026] S1, Raw material pretreatment: The acidic scale remover is ultra - micro - pulverized to D50≤30μm, and the corrosion inhibitor is premixed with 1 / 3 of the excipient to prevent agglomeration.

[0027] S2, Gradient mixing: Use a V - type mixer to feed materials in three steps:

[0028] (1) Acidic scale remover and 1 / 2 of the excipient;

[0029] (2) Corrosion inhibitor and color - changing indicator;

[0030] (3) Surfactant and the remaining excipient;

[0031] S3, Wet granulation: Spray - add 5% PVP ethanol solution, control the water content of the wet granules at 12 - 15%, and obtain the core - layer material.

[0032] S4, Double - layer tableting: Input the core - layer material and the outer - layer material into the tableting equipment, and press the core - layer material inside the outer - layer material to obtain the finished product of the solid color - changing scale remover.

[0033] A preparation device for a solid color-changing scale remover, the preparation device being used to prepare a solid color-changing scale remover, the preparation device including a tablet pressing device, the tablet pressing device including a feeding device, the feeding device being used to fill a core layer material and an outer layer material into a mold of the tablet pressing device, the feeding device including:

[0034] An outer feeding pipe, which is used to convey the outer layer material into the mold and is longitudinally slidably arranged above the mold;

[0035] An inner feeding pipe, which is used to convey the core layer material into the mold and is coaxially and fixedly arranged inside the outer feeding pipe, the lower end face of the inner feeding pipe is higher than the lower end face of the outer feeding pipe, and the distance value between the lower end face of the inner feeding pipe and the lower end face of the outer feeding pipe is not less than the thickness value of the outer layer;

[0036] An outer opening and closing mechanism, which is used to control the opening and closing of the outer feeding pipe. When the lower end of the outer feeding pipe approaches the cavity of the mold, the outer opening and closing mechanism makes the outer feeding pipe in an open state. When the outer feeding pipe is far away from the cavity of the mold, the outer opening and closing mechanism makes the outer feeding pipe in a closed state;

[0037] An inner opening and closing mechanism, which is used to control the opening and closing of the inner feeding pipe. After the lower end of the inner feeding pipe approaches the cavity of the mold and the outer feeding pipe is in an open state, the inner opening and closing mechanism makes the outer feeding pipe in an open state. Before the lower end of the inner feeding pipe is far away from the cavity of the mold and the outer feeding pipe is in a closed state, the inner opening and closing mechanism makes the inner feeding pipe in a closed state.

[0038] To further implement the present invention, the following technical solutions can be preferably selected:

[0039] Preferably, it further includes:

[0040] An outer hopper, which is used to store the outer layer material and is arranged at the upper end of the outer feeding pipe;

[0041] An inner hopper, which is used to store the core layer material and is arranged at the upper end of the inner feeding pipe;

[0042] Both the outer hopper and the inner hopper are conical shells with a larger upper part and a smaller lower part, and the upper end of the inner feeding pipe extends into the outer hopper.

[0043] Preferably, the outer opening and closing mechanism includes:

[0044] An outer opening and closing plug, which is annular, the outer opening and closing plug is located in the outer hopper and is axially slidably sleeved outside the inner feeding pipe, the inner side of the outer opening and closing plug is hermetically and slidably attached to the outside of the inner feeding pipe, and when the outer opening and closing plug is in the lowest position, the outer side of the outer opening and closing plug is hermetically attached to the inner side of the outer hopper;

[0045] An outer positioning rod, which is vertically arranged below the outer opening and closing plug. When the outer opening and closing plug is in the lowest position, the lower end of the outer positioning rod extends downward out of the outer feeding pipe, and the distance value between the lower end of the outer positioning rod and the lower end of the outer feeding pipe is not less than the thickness value of the solid color-changing scale remover;

[0046] The inner opening and closing mechanism includes:

[0047] An inner opening and closing plug, which is spherical in shape. The inner opening and closing plug is located inside the inner hopper and is axially slidably arranged on the inner feed pipe. When the inner opening and closing plug is in the lowest position, the outer side of the inner opening and closing plug is hermetically attached to the inner side of the inner hopper;

[0048] An inner positioning rod, which is vertically arranged on the lower side of the inner opening and closing plug. When the inner opening and closing plug is in the lowest position, the lower end of the inner positioning rod extends downward out of the inner feed pipe and is above the lower end of the outer positioning rod. The distance value between the lower end of the inner positioning rod and the lower end of the inner feed pipe is not less than the thickness value of the core layer, and the distance value between the lower end of the inner positioning rod and the lower end of the outer positioning rod is not less than the thickness value of the outer layer.

[0049] Preferably, springs are provided between the outer opening and closing plug and the outer hopper and between the inner opening and closing plug and the inner hopper. The springs drive the outer opening and closing plug and the inner opening and closing plug to move downward, so that the outer opening and closing plug and the inner opening and closing plug are hermetically attached to the outer hopper and the inner hopper respectively.

[0050] The beneficial effects of the present invention are:

[0051] 1. The scale remover of the present invention is solid, small in volume, and convenient for transportation and use. The color-changing indicator is modified by embedding with hydroxypropyl-β-cyclodextrin and nitration, which can significantly improve the detection limit, color difference, stability and anti-interference performance.

[0052] 2. The color-changing indicator of the present invention includes bromocresol green-phenol red complex and diphenylcarbazide. The bromocresol green-phenol red complex realizes color change through the change of the dissociation degree of phenolic hydroxyl groups, which is suitable for monitoring acidic and alkaline environments and is used to indicate the content of acidic scale remover in the scale remover. Diphenylcarbazide forms a red complex with iron ions, which is suitable for monitoring the redox potential and is used to indicate the scale removal state, thus realizing two-dimensional color change.

[0053] The spectra of bromocresol green-phenol red complex and diphenylcarbazide are superimposed. Bromocresol green-phenol red shows continuous color change of "yellow → green → purple" in the range of pH 4.0 - 8.0, covering multiple bands of visible light. Diphenylcarbazide reacts with Fe 30 to form a red complex, which has a strong absorption peak at 550 - 600 nm. The spectra of the two indicators after combination are superimposed, making the color contrast more distinct, and the color difference ΔE is increased from 15 - 20 to 25. Moreover, the purple of bromocresol green-phenol red and the red of diphenylcarbazide are close to complementary colors on the color wheel, producing a stronger visual impact after mixing.

[0054] Meanwhile, the combination of the two also improves stability. Bromocresol green-phenol red and diphenylcarbazide form hydrogen bonds or π-π stacking in solution, reducing the molecular free energy and enhancing the thermal stability. The phenolic hydroxyl group of bromocresol green-phenol red can scavenge free radicals and protect diphenylcarbazide from oxidation; the reducibility of diphenylcarbazide can prevent bromocresol green-phenol red from being over-oxidized.

[0055] 3. The preparation method of the present invention adopts a gradient mixing process to ensure stability. The step-by-step feeding reduces component interference. In the first step, an acidic matrix framework is preferentially formed to avoid the direct contact failure of the corrosion inhibitor with strong acid. In the second step, it is uniformly dispersed in the premixed acidic matrix to protect the photosensitivity of the indicator. In the third step, the core components are coated on the outer layer to reduce caking due to moisture absorption during the storage period.

[0056] The double-layer tablet pressing technology is adopted to strengthen the functional synergy. The core layer has rapid release and high-efficiency response, quickly releasing acidic components, achieving scale dissolution and pH color change feedback within 10 minutes, with a sensitivity of ΔpH = 0.05. The outer layer has sustained release protection and long-acting controlled release. The hydroxypropyl methylcellulose coating layer is used for sustained release for 6-8 hours, reducing the impact of the one-time release of acid solution on the equipment.

[0057] 4. The preparation equipment of the present invention enables double-layer tablet pressing by using ordinary tablet pressing equipment through the feeding device. During injection, through the coordinated control of the outer opening and closing mechanism and the inner opening and closing mechanism, the outer layer material in the die cavity is located outside the core layer material, and double-layer pressing can be completed in a single tablet pressing, without the need for step-by-step tablet pressing of the core layer and the outer layer, improving the production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a schematic structural diagram of the feeding device of the present invention.

[0059] Figure 2 It is a sectional view of the feeding device of the present invention in the closed state.

[0060] Figure 3 It is a schematic position diagram of the feeding device of the present invention when injecting the outer layer material into the lower part of the die cavity.

[0061] Figure 4 It is a schematic position diagram of the feeding device of the present invention when injecting the outer layer material and the core layer material into the middle part of the die cavity.

[0062] Figure 5 It is a schematic position diagram of the feeding device of the present invention when injecting the outer layer material into the upper part of the die cavity.

[0063] The reference numerals are:

[0064] 1 - outer feed pipe; 2 - inner feed pipe; 3 - outer hopper; 4 - inner hopper; 5 - outer closing plug; 6 - outer positioning rod; 7 - inner closing plug; 8 - inner positioning rod. DETAILED DESCRIPTION OF THE INVENTION

[0065] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "arranged", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

[0067] Embodiment 1

[0068] This embodiment discloses a solid color-changing scale remover, which includes a core layer and an outer layer. The core layer is wrapped inside the outer layer, and the core layer is composed of the following formula components:

[0069]

[0070]

[0071] Among them, the bromocresol green-phenol red complex is subjected to hydroxypropyl-β-cyclodextrin embedding and nitro modification, and the modification effects are as follows:

[0072] Performance indicators Unmodified After modification (embedding + modification) Improvement rate Color change range pH 4.0 - 8.0 pH 3.5 - 8.5 +12.5％ Response time 30-60s ≤10s -83％ Detection limit pH 0.1 pH 0.03 +70％ Stability (months) 6 12 +100％ Salt resistance Tolerant to 0.5 mol / L NaCl Tolerant to 2 mol / L NaCl +300％

[0073] The comparison of the order of simultaneous embedding modification and modification modification of the bromocresol green-phenol red complex is as follows:

[0074] Performance indicators Embed first then modify Modify first then embed Improvement rate Color change sensitivity ΔpH = 0.05 ΔpH = 0.03 +40％ Embedding rate 90％ 95％ +5.6％ Stability (months) 9 12 +33％ Salt resistance Tolerant to 1.5 mol / L NaCl Tolerant to 2.0 mol / L NaCl +33％

[0075] The comparison of the effects of using the bromocresol green-phenol red complex and diphenylcarbazide as the color-changing indicator is as follows:

[0076]

[0077] The hydroxypropyl-β-cyclodextrin embedding process includes the following steps:

[0078] Sa. Solution preparation: Dissolve the bromocresol green-phenol red complex in ethanol to obtain a bromocresol green-phenol red ethanol solution, and dissolve hydroxypropyl-β-cyclodextrin in deionized water to obtain a hydroxypropyl-β-cyclodextrin aqueous solution;

[0079] Sb, embedding reaction: Slowly add the bromocresol green - phenol red ethanol solution dropwise to the hydroxypropyl - β - cyclodextrin aqueous solution. After the addition is complete, continue stirring and reacting for 4 hours;

[0080] Sc, removing the solvent: Evaporate under reduced pressure at 40 °C to remove ethanol and part of the water, pre - freeze to - 40 °C, and then vacuum dry for 24 hours to obtain the embedded product;

[0081] Sd, purification: Dissolve the embedded product in deionized water and filter to remove the un - embedded bromocresol green - phenol red.

[0082] The nitro - modification process includes the following steps:

[0083] SA, nitration reaction: In an ice - water bath, dissolve the bromocresol green - phenol red complex in concentrated sulfuric acid, stir until completely dissolved, slowly add concentrated nitric acid. After the addition is complete, continue stirring and reacting for 2 hours;

[0084] SB, post - treatment: Slowly pour the reaction solution into ice water to precipitate a yellow solid. Filter the precipitate, wash it with cold water until neutral, and then vacuum dry to obtain the nitro - modified bromocresol green - phenol red complex;

[0085] SC, purification: Recrystallize using an ethanol - water mixed solvent to remove unreacted raw materials and by - products;

[0086] When the bromocresol green - phenol red complex is simultaneously subjected to hydroxypropyl - β - cyclodextrin embedding and nitro - modification, nitro - modification is carried out first, and then hydroxypropyl - β - cyclodextrin embedding.

[0087] The scale remover of the present invention is a solid, with a small volume, which is convenient for transportation and use. The color - changing indicator is modified by hydroxypropyl - β - cyclodextrin embedding and nitro - modification, which can significantly improve the detection limit, color difference, stability and anti - interference performance.

[0088] The color - changing indicator of the present invention includes a bromocresol green - phenol red complex and diphenylcarbazide. The bromocresol green - phenol red complex realizes color change through the change of the dissociation degree of phenolic hydroxyl groups, which is suitable for monitoring acidic and alkaline environments and is used to indicate the content of acidic scale removers in the scale remover. Diphenylcarbazide forms a red complex with iron ions, which is suitable for monitoring the redox potential and is used to indicate the scale removal state, thus realizing two - dimensional color change.

[0089] The spectra of the bromocresol green - phenol red complex and diphenylcarbazide overlap. The bromocresol green - phenol red shows continuous color change of "yellow → green → purple" in the range of pH 4.0 - 8.0, covering multiple bands of visible light. Diphenylcarbazide and Fe 30A red complex is formed during the reaction, which has a strong absorption peak at 550 - 600 nm. After compounding, the spectra of the two indicators are superimposed, making the color contrast more distinct, and the color difference ΔE is increased from 15 - 20 to 25. Moreover, the purple of bromocresol green - phenol red and the red of diphenylcarbazide are close to complementary colors on the color wheel, and stronger visual impact is produced after mixing.

[0090] Meanwhile, the combination of the two also improves the stability. Bromocresol green - phenol red and diphenylcarbazide form hydrogen bonds or π - π stacking in the solution, reducing the molecular free energy and enhancing the thermal stability. The phenolic hydroxyl group of bromocresol green - phenol red can scavenge free radicals to protect diphenylcarbazide from oxidation; the reducibility of diphenylcarbazide can prevent bromocresol green - phenol red from being over - oxidized.

[0091] Example Two

[0092] A preparation method of a solid - color - changing scale remover, the preparation method includes the following steps:

[0093] S1. Raw material pretreatment: The acidic scale remover is ultra - micro - pulverized to D50 ≤ 30 μm, and the corrosion inhibitor is premixed with 1 / 3 of the excipient to prevent agglomeration;

[0094] S2. Gradient mixing: Use a V - type mixer to feed materials in three steps:

[0095] (1) The acidic scale remover and 1 / 2 of the excipient;

[0096] (2) The corrosion inhibitor and the color - changing indicator;

[0097] (3) The surfactant and the remaining excipient;

[0098] S3. Wet granulation: Spray - add 5% PVP ethanol solution, and control the water content of the wet granules to be 12 - 15% to obtain the core - layer material;

[0099] S4. Double - layer tableting: Input the core - layer material and the outer - layer material into the tableting equipment, and press the core - layer material inside the outer - layer material to obtain the finished product of the solid - color - changing scale remover.

[0100] The gradient mixing process is adopted to ensure stability. Feeding materials step by step reduces component interference. In the first step, an acidic matrix framework is preferentially formed to avoid the corrosion inhibitor from directly contacting with strong acid and becoming ineffective. In the second step, it is uniformly dispersed in the premixed acidic matrix to protect the photosensitivity of the indicator. In the third step, the core components are coated on the outside to reduce moisture absorption and caking during the storage period.

[0101] The double - layer tableting technology is adopted to strengthen the functional synergy. The core layer has rapid release and high - efficiency response, quickly releasing acidic components, achieving scale dissolution and pH color - change feedback within 10 minutes, with a sensitivity of ΔpH = 0.05. The outer layer has slow release and protection for long - term controlled release. Using a hydroxypropyl methylcellulose coating layer, it has a slow release of 6 - 8 hours, reducing the impact of the one - time release of acid solution on the equipment.

[0102] Example 3

[0103] In Example 2, the double-layer tabletting technology is adopted. At present, most special double-layer tablet presses are used for tabletting, such as Fette 3090, Manesty Dry-Cota, and Korsch XL 800. However, such tablet presses are expensive, and the core layer and the outer layer need to be tabletted step by step, and the pressing efficiency is also low.

[0104] The volume of the fixed scale remover is much larger than that of ordinary tablets. The ordinary tablet press can use the feeding device in this embodiment to make the outer layer material in the die cavity of the mold located outside the core layer material, and the double-layer pressing can be completed by single pressing, without the need for step-by-step pressing of the core layer and the outer layer, improving the production efficiency.

[0105] As Figure 1 and Figure 2 shown, a preparation device for a solid discoloring scale remover, the preparation device includes a tabletting device, the tabletting device includes a feeding device, the feeding device is used to fill the core layer material and the outer layer material into the mold of the tabletting device, and the feeding device includes:

[0106] An outer feeding pipe 1, which is used to convey the outer layer material into the mold and is longitudinally slidably arranged above the mold;

[0107] An inner feeding pipe 2, which is used to convey the core layer material into the mold and is coaxially and fixedly arranged in the outer feeding pipe 1. The lower end surface of the inner feeding pipe 2 is higher than the lower end surface of the outer feeding pipe 1, and the distance value between the lower end surface of the inner feeding pipe 2 and the lower end surface of the outer feeding pipe 1 is not less than the thickness value of the outer layer;

[0108] An outer opening and closing mechanism, which is used to control the opening and closing of the outer feeding pipe 1. When the lower end of the outer feeding pipe 1 is close to the die cavity of the mold, the outer opening and closing mechanism makes the outer feeding pipe 1 in an open state. When the outer feeding pipe 1 is far from the die cavity of the mold, the outer opening and closing mechanism makes the outer feeding pipe 1 in a closed state;

[0109] An inner opening and closing mechanism, which is used to control the opening and closing of the inner feeding pipe 2. After the lower end of the inner feeding pipe 2 is close to the die cavity of the mold and the outer feeding pipe 1 is in an open state, the inner opening and closing mechanism makes the outer feeding pipe 1 in an open state. Before the lower end of the inner feeding pipe 2 is far from the die cavity of the mold and the outer feeding pipe 1 is in a closed state, the inner opening and closing mechanism makes the inner feeding pipe 2 in a closed state.

[0110] It further includes:

[0111] An outer hopper 3, which is used to store the outer layer material and is arranged at the upper end of the outer feeding pipe 1;

[0112] An inner hopper 4, which is used to store the core layer material and is arranged at the upper end of the inner feeding pipe 2;

[0113] Both the outer hopper 3 and the inner hopper 4 are conical shells with a larger upper part and a smaller lower part, and the upper end of the inner feed pipe 2 extends into the outer hopper 3.

[0114] The outer opening and closing mechanism includes:

[0115] An outer opening and closing plug 5, which is annular. The outer opening and closing plug 5 is located in the outer hopper 3 and axially slidably sleeved outside the inner feed pipe 2. The inner side of the outer opening and closing plug 5 is hermetically and slidably attached to the outer side of the inner feed pipe 2. When the outer opening and closing plug 5 is in the lowermost position, the outer side of the outer opening and closing plug 5 is hermetically attached to the inner side of the outer hopper 3;

[0116] An outer positioning rod 6, which is vertically arranged on the lower side of the outer opening and closing plug 5. When the outer opening and closing plug 5 is in the lowermost position, the lower end of the outer positioning rod 6 extends downward out of the outer feed pipe 1, and the distance value between the lower end of the outer positioning rod 6 and the lower end of the outer feed pipe 1 is not less than the thickness value of the solid discoloring scale remover;

[0117] The inner opening and closing mechanism includes:

[0118] An inner opening and closing plug 7, which is spherical. The inner opening and closing plug 7 is located in the inner hopper 4 and axially slidably arranged on the inner feed pipe 2. When the inner opening and closing plug 7 is in the lowermost position, the outer side of the inner opening and closing plug 7 is hermetically attached to the inner side of the inner hopper 4;

[0119] An inner positioning rod 8, which is vertically arranged on the lower side of the inner opening and closing plug 7. When the inner opening and closing plug 7 is in the lowermost position, the lower end of the inner positioning rod 8 extends downward out of the inner feed pipe 2 and is above the lower end of the outer positioning rod 6. The distance value between the lower end of the inner positioning rod 8 and the lower end of the inner feed pipe 2 is not less than the thickness value of the core layer, and the distance value between the lower end of the inner positioning rod 8 and the lower end of the outer positioning rod 6 is not less than the thickness value of the outer layer.

[0120] Springs are provided between the outer opening and closing plug 5 and the outer hopper 3 and between the inner opening and closing plug 7 and the inner hopper 4. The springs drive the outer opening and closing plug 5 and the inner opening and closing plug 7 to move downward, so that the outer opening and closing plug 5 and the inner opening and closing plug 7 are hermetically attached to the outer hopper 3 and the inner hopper 4 respectively.

[0121] As Figures 3 - 5As shown in the figure, when injecting materials into the die cavity of the mold, the feeding device moves downward relative to the mold. The outer positioning rod 6 first abuts against the bottom surface of the die cavity, driving the outer opening and closing plug 5 to move upward, so that the outer feeding pipe 1 is in an open state. The outer layer material in the outer hopper 3 enters the lower part of the die cavity through the outer feeding pipe 1. Then the inner positioning rod 8 abuts against the bottom surface of the die cavity, driving the inner opening and closing plug 7 to move upward, so that the inner feeding pipe 2 is in an open state. At this time, the core layer material in the inner hopper 4 enters the center of the middle part of the die cavity through the outer feeding pipe 1, and the outer layer material in the outer hopper 3 enters the periphery of the middle part of the die cavity through the outer feeding pipe 1. Then the feeding device moves upward relative to the mold, and the inner positioning rod 8 disengages from the bottom surface of the die cavity. The elastic force of the spring and the gravity of the inner opening and closing plug 7 cause the inner opening and closing plug 7 to move downward, so that the inner feeding pipe 2 is in a closed state. At this time, due to the support of the outer positioning rod 6, the outer feeding pipe 1 remains in an open state, and the outer layer material in the outer hopper 3 enters the upper part of the die cavity through the outer feeding pipe 1. The feeding device continues to move upward relative to the mold, and the outer positioning rod 6 disengages from the bottom surface of the die cavity. The elastic force of the spring and the gravity of the outer opening and closing plug 5 cause the outer opening and closing plug 5 to move downward, so that the outer feeding pipe 1 is in a closed state, completing the material injection process.

[0122] By using the feeding device, double-layer tablet pressing can be achieved with ordinary tablet pressing equipment. During material injection, through the coordinated control of the outer opening and closing mechanism and the inner opening and closing mechanism, the outer layer material in the die cavity of the mold is located outside the core layer material, and double-layer pressing can be completed in a single tablet pressing, without the need for step-by-step tablet pressing of the core layer and the outer layer, improving the production efficiency.

[0123] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A solid color-changing scale remover, characterized in that, It includes a core layer and an outer layer, with the core layer wrapped inside the outer layer. The core layer is composed of the following formula components by mass percentage: 60%-75% acidic descaling agent, 4%-7% corrosion inhibitor, 0.5%-1% color-changing indicator, 15%-23% excipient, and 2%-3% surfactant; Among them, the color-changing indicator is a modified bromocresol green-phenol red complex, and the modification of the bromocresol green-phenol red complex is one or a combination of two of hydroxypropyl-β-cyclodextrin embedding and nitro modification.

2. The solid discoloring scale remover according to claim 1, characterized in that, The acidic descaling agent is glycolic acid and aminosulfonic acid, and the mass ratio of glycolic acid to aminosulfonic acid is 3:1; The corrosion inhibitor is ethylenediaminetetramethylenephosphonic acid and benzotriazole, and the mass ratio of ethylenediaminetetramethylenephosphonic acid to benzotriazole is 3:1; The excipient is microcrystalline cellulose and polyethylene glycol 6000, and the mass ratio of microcrystalline cellulose to polyethylene glycol 6000 is 2:1; The surfactant is sodium dodecylbenzenesulfonate.

3. The solid discoloring water scale remover according to claim 1, characterized in that, The hydroxypropyl-β-cyclodextrin embedding process includes the following steps: Sa. Solution preparation: Dissolve the bromocresol green-phenol red complex in ethanol to obtain a bromocresol green-phenol red ethanol solution, and dissolve hydroxypropyl-β-cyclodextrin in deionized water to obtain a hydroxypropyl-β-cyclodextrin aqueous solution; Sb. Embedding reaction: Slowly drop the bromocresol green-phenol red ethanol solution into the hydroxypropyl-β-cyclodextrin aqueous solution. After dropping, continue to stir and react for 4 hours; Sc. Solvent removal: Evaporate under reduced pressure at 40°C to remove ethanol and part of the water, pre-freeze to -40°C, and then vacuum dry for 24 hours to obtain the embedded product; Sd. Purification: Dissolve the embedded product in deionized water and filter to remove the unembedded bromocresol green-phenol red.

4. The solid color-changing scale remover according to claim 1, wherein The nitro modification process includes the following steps: SA. Nitration reaction: In an ice-water bath, dissolve the bromocresol green-phenol red complex in concentrated sulfuric acid, stir until completely dissolved, slowly drop in concentrated nitric acid, and continue to stir and react for 2 hours after dropping; SB. Post-treatment: Slowly pour the reaction solution into ice water to precipitate a yellow precipitate. Filter the precipitate, wash it with cold water until neutral, and vacuum dry to obtain the nitro-modified bromocresol green-phenol red complex; SC. Purification: Recrystallize using an ethanol-water mixed solvent to remove unreacted raw materials and by-products; When the bromocresol green-phenol red complex is simultaneously subjected to hydroxypropyl-β-cyclodextrin embedding and nitro modification, nitro modification is carried out first, and then hydroxypropyl-β-cyclodextrin embedding.

5. A solid color-changing scale remover according to claim 1, characterized in that, The color-changing indicator also includes diphenylcarbazide, and the mass ratio of diphenylcarbazide to the bromocresol green-phenol red complex is 1:1 - 1:

10.

6. A preparation method of a solid color-changing scale remover, characterized in that The preparation method is used to prepare a solid color-changing scale remover as described in any one of claims 1-5. The preparation method includes the following steps: S1. Raw material pretreatment: The acidic descaling agent is ultra-finely pulverized to D50≤30μm, and the corrosion inhibitor is premixed with 1 / 3 of the excipient to prevent agglomeration; S2. Gradient mixing: Use a V-type mixer to feed materials in three steps: (1) Acidic descaling agent and 1 / 2 of the excipient; (2) Corrosion inhibitor and color-changing indicator; (3) Surfactant and the remaining excipient; S3. Wet granulation, spray 5% PVP ethanol solution, control the water content of wet granules at 12 - 15% to obtain the core layer material; S4. Double - layer tableting, input the core layer material and the outer layer material into the tableting equipment, press the core layer material into the outer layer material to obtain the finished product of the solid color - changing scale remover.

7. A preparation device for a solid discoloring scale remover, the preparation device being used to prepare a solid discoloring scale remover as described in any one of claims 1-5, the preparation device including a tabletting device, characterized in that, The tableting equipment includes a feeding device. The feeding device is used to fill the core layer material and the outer layer material into the mold of the tableting equipment. The feeding device includes: An outer feeding pipe (1), which is used to convey the outer layer material into the mold and is longitudinally slidably arranged above the mold; An inner feeding pipe (2), which is used to convey the core layer material into the mold and is coaxially and fixedly arranged inside the outer feeding pipe (1). The lower end face of the inner feeding pipe (2) is higher than the lower end face of the outer feeding pipe (1), and the distance value between the lower end face of the inner feeding pipe (2) and the lower end face of the outer feeding pipe (1) is not less than the thickness value of the outer layer; An outer opening - closing mechanism, which is used to control the opening and closing of the outer feeding pipe (1). When the lower end of the outer feeding pipe (1) approaches the cavity of the mold, the outer opening - closing mechanism makes the outer feeding pipe (1) in an open state. When the outer feeding pipe (1) is far from the cavity of the mold, the outer opening - closing mechanism makes the outer feeding pipe (1) in a closed state; An inner opening - closing mechanism, which is used to control the opening and closing of the inner feeding pipe (2). After the lower end of the inner feeding pipe (2) approaches the cavity of the mold and the outer feeding pipe (1) is in an open state, the inner opening - closing mechanism makes the inner feeding pipe (2) in an open state. Before the lower end of the inner feeding pipe (2) is far from the cavity of the mold and the outer feeding pipe (1) is in a closed state, the inner opening - closing mechanism makes the inner feeding pipe (2) in a closed state.

8. The preparation equipment of a solid color-changing scale remover according to claim 7, characterized in that, It further includes: An outer hopper (3), which is used to store the outer layer material and is arranged at the upper end of the outer feeding pipe (1); An inner hopper (4), which is used to store the core layer material and is arranged at the upper end of the inner feeding pipe (2); Both the outer hopper (3) and the inner hopper (4) are conical shells with a larger upper part and a smaller lower part, and the upper end of the inner feeding pipe (2) extends into the outer hopper (3).

9. The preparation equipment of a solid discoloring scale remover according to claim 8, characterized in that, The outer opening - closing mechanism includes: An outer closing plug (5), which is annular. The outer closing plug (5) is located in the outer hopper (3) and axially slidably sleeved outside the inner feeding pipe (2). The inner side of the outer closing plug (5) is hermetically and slidably attached to the outer side of the inner feeding pipe (2). When the outer closing plug (5) is in the lowest position, the outer side of the outer closing plug (5) is hermetically attached to the inner side of the outer hopper (3); An outer positioning rod (6), which is vertically arranged below the outer closing plug (5). When the outer closing plug (5) is in the lowest position, the lower end of the outer positioning rod (6) extends downward out of the outer feeding pipe (1), and the distance value between the lower end of the outer positioning rod (6) and the lower end of the outer feeding pipe (1) is not less than the thickness value of the solid color - changing scale remover; The inner opening - closing mechanism includes: An inner closing plug (7), which is spherical. The inner closing plug (7) is located in the inner hopper (4) and axially slidably arranged inside the inner feeding pipe (2). When the inner closing plug (7) is in the lowest position, the outer side of the inner closing plug (7) is hermetically attached to the inner side of the inner hopper (4); An inner positioning rod (8), which is vertically arranged below the inner opening and closing plug (7). When the inner opening and closing plug (7) is in the lowest position, the lower end of the inner positioning rod (8) extends downward out of the inner feeding pipe (2) and is above the lower end of the outer positioning rod (6). The distance value between the lower end of the inner positioning rod (8) and the lower end of the inner feeding pipe (2) is not less than the thickness value of the core layer, and the distance value between the lower end of the inner positioning rod (8) and the lower end of the outer positioning rod (6) is not less than the thickness value of the outer layer.

10. The preparation equipment of a solid color-changing scale remover according to claim 9, characterized in that, Springs are provided between the outer opening and closing plug (5) and the outer hopper (3) and between the inner opening and closing plug (7) and the inner hopper (4). The springs drive the outer opening and closing plug (5) and the inner opening and closing plug (7) to move downward, so that the outer opening and closing plug (5) and the inner opening and closing plug (7) are respectively in sealing fit with the outer hopper (3) and the inner hopper (4).

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