Compound fertilizer total nitrogen determination device and compound fertilizer total nitrogen determination system
Patent Information
- Application Number
- CN202522174429.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-14
- Publication Date
- 2026-10-27
- Estimated Expiration
- 2035-10-14
AI Technical Summary
[0003]但是，凯氏定氮法消解设备复杂且消解终点判断困难，消解是否完全通常依赖经验，如观察溶液颜色或消解时间，易导致消解不完全(氮损失)或过度消解(硫酸过度挥发)，影响测定准确性
[0028]相较于现有技术，本申请提供的复合肥总氮测定装置，直接利用反应器进行氮肥样品和浓硫酸的反应取代专用器械，降低成本以及操作难度，并通过指示件色态变化的客观现象对反应终点进行快速且明确的指示，大大提高反应终点判定的准确性，进一步地提高测定结果的准确性；同时通过吸收器的设置对反应器内多余的浓硫酸进行吸收，防止其挥发污染空气，且降低测定反应的环境限制，实现普通环境下也可以进行测定，提高测定效率；从而解决现有技术中复合肥总氮含量测定过程中消解终点判断准确性低的技术问题。
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Figure CN224906784U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of experimental measurement technology, and in particular to a compound fertilizer total nitrogen measuring device and a compound fertilizer total nitrogen measuring system. Background Technology
[0002] The determination of total nitrogen in compound fertilizers usually employs the Kjeldahl method, whose core steps include digestion, distillation, and titration.
[0003] However, the Kjeldahl method for nitrogen determination involves complex digestion equipment and makes it difficult to determine the digestion endpoint. Whether digestion is complete usually depends on experience, such as observing the solution color or digestion time, which can easily lead to incomplete digestion (nitrogen loss) or over-digestion (excessive volatilization of sulfuric acid), affecting the accuracy of the determination. Utility Model Content
[0004] The first aspect of this application provides a compound fertilizer total nitrogen determination device, which includes...
[0005] A reactor having a containment space for containing nitrogen fertilizer samples and concentrated sulfuric acid, the top of the reactor having an opening to connect the inside and outside of the containment space, and at least a designated area of the reactor facing downwards from the opening being transparent;
[0006] An indicator is detachably mounted on the inner wall of the designated area, and the indicator has a first color state and a second color state; the indicator changes from the first color state to the second color state after the reaction between the nitrogen fertilizer sample and concentrated sulfuric acid is completed.
[0007] An absorber, detachably disposed at the opening, is used to absorb acid mist emitted from concentrated sulfuric acid within the containment space.
[0008] In some modified embodiments of the first aspect of this application, the aforementioned compound fertilizer total nitrogen determination device further includes a reaction zone in the reactor.
[0009] The reaction zone is located on the side of the designated area away from the opening, and the reaction zone is connected to the designated area. The reaction zone is used to contain nitrogen fertilizer samples and concentrated sulfuric acid.
[0010] The size of the reaction region gradually decreases from the opening.
[0011] In some modified embodiments of the first aspect of this application, the aforementioned compound fertilizer total nitrogen measuring device, wherein the indicator is continuously arranged around the opening for one revolution.
[0012] In some modified embodiments of the first aspect of this application, the aforementioned compound fertilizer total nitrogen measuring device, wherein the indicator comprises ceramic fiber and target indicator;
[0013] The target indicator is completely impregnated with the ceramic fiber and air-dried to reveal the first color state.
[0014] In some modified embodiments of the first aspect of this application, the aforementioned compound fertilizer total nitrogen measuring device has an indicator thickness of up to 0.5 mm.
[0015] In some modified embodiments of the first aspect of this application, the aforementioned compound fertilizer total nitrogen measuring device, wherein the absorber includes an absorption hood and a neutralizing element;
[0016] The absorption cover has a second receiving space for accommodating the neutralizing component, and the absorption cover has a second opening that connects the inside and outside of the second receiving space. The second opening is detachably connected to the opening.
[0017] The neutralizing element is detachably disposed within the second accommodating space, and the neutralizing element is used to absorb and neutralize the acid mist.
[0018] In some modified embodiments of the first aspect of this application, the aforementioned compound fertilizer total nitrogen measuring device has an elasticity at least at the second opening on the absorption shroud.
[0019] In some modified embodiments of the first aspect of this application, the aforementioned compound fertilizer total nitrogen determination device, wherein the neutralizing element includes an absorber and a neutralizing reagent;
[0020] The absorbent is absorbent and flexible, so as to deform when passing through the second opening;
[0021] The neutralizing agent wets the absorber for neutralizing the acid mist.
[0022] In some modified embodiments of the first aspect of this application, in the aforementioned compound fertilizer total nitrogen measuring device, at least one protrusion is provided on the circumferential inner wall of the second opening, the protrusion being used to abut against the outer wall of the opening.
[0023] The second aspect of this application provides a system for determining total nitrogen in compound fertilizers, comprising:
[0024] At least one compound fertilizer total nitrogen determination device, comprising:
[0025] A reactor having a containment space for containing nitrogen fertilizer samples and concentrated sulfuric acid, the top of the reactor having an opening to connect the inside and outside of the containment space, and at least a designated area of the reactor facing downwards from the opening being transparent;
[0026] An indicator is detachably mounted on the inner wall of the designated area, and the indicator has a first color state and a second color state; the indicator changes from the first color state to the second color state after the reaction between the nitrogen fertilizer sample and concentrated sulfuric acid is completed.
[0027] An absorber, detachably disposed at the opening, is used to absorb acid mist emitted from concentrated sulfuric acid within the containment space.
[0028] Compared to existing technologies, the compound fertilizer total nitrogen determination device provided in this application directly utilizes a reactor to react nitrogen fertilizer samples with concentrated sulfuric acid, replacing specialized equipment, reducing costs and operational difficulty. Furthermore, it uses the objective phenomenon of color change in the indicator to quickly and clearly indicate the reaction endpoint, greatly improving the accuracy of endpoint determination and further enhancing the accuracy of the measurement results. Simultaneously, the absorption device absorbs excess concentrated sulfuric acid in the reactor, preventing its volatilization and air pollution, and reducing environmental limitations for the reaction, enabling measurement even under ordinary conditions, thus improving measurement efficiency. This solves the technical problem of low accuracy in determining the digestion endpoint during the determination of total nitrogen content in compound fertilizers in existing technologies. Attached Figure Description
[0029] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein:
[0030] Figure 1 A schematic diagram of the structure of the compound fertilizer total nitrogen determination device provided in this embodiment is shown.
[0031] Figure 2 schematically shown Figure 1 Schematic diagram of the cross section along AA;
[0032] Figure 3 An exploded structural diagram of the compound fertilizer total nitrogen measuring device provided in this embodiment is shown schematically.
[0033] The reference numerals in the attached diagram are as follows: Reactor 1, Opening 11, Designated Area 12, Reaction Area 13, Indicator 2, Absorber 3, Absorption Shield 31, Neutralizer 32, Second Opening 33, Protrusion 34. Detailed Implementation
[0034] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
[0035] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined. "Vertical" is not strictly vertical, but...
[0036] It is within the allowable error range. "Parallel" is not parallel in the strict sense, but rather within the allowable error range. Words such as "include" or "contain" mean that the element preceding the word covers the element listed after the word, and do not exclude the possibility of covering other elements as well.
[0037] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0038] These embodiments are provided to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values set forth in these embodiments should be interpreted as exemplary only and not as limiting.
[0039] It should be noted that, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this disclosure 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, and therefore should not be construed as a limitation of this disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0040] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" 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 direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.
[0041] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application pertains;
[0042] It should be noted that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that there can be three relationships, such as A and / or B. Specifically, it can be understood as: A and B can be included at the same time, A can exist alone, or B can exist alone, and any of the above three situations can be met.
[0043] The technical solution of this application embodiment is to solve the above-mentioned technical problems, and the idea is as follows:
[0044] Example 1
[0045] Reference Appendix Figure 1 and attached Figure 2 The compound fertilizer total nitrogen determination device provided in this application includes a reactor 1, an indicator 2, and an absorber 3. The reactor 1 has a containment space for containing nitrogen fertilizer samples and concentrated sulfuric acid. The top of the reactor 1 has an opening 11 to connect the inside and outside of the containment space. At least the designated area 12 of the reactor 1 facing downwards from the opening 11 is transparent. The indicator 2 is detachably disposed on the inner wall of the designated area 12. The indicator 2 has a first color state and a second color state. After the reaction between the nitrogen fertilizer sample and concentrated sulfuric acid is completed, the indicator 2 can change from the first color state to the second color state. The absorber 3 is detachably disposed on the opening 11. The absorber 3 is used to absorb the acid mist volatilized from the concentrated sulfuric acid in the containment space.
[0046] Understandably, in order to solve the technical problem of low accuracy in determining the digestion endpoint during the determination of total nitrogen content in compound fertilizers in the prior art, the compound fertilizer total nitrogen determination device provided in this embodiment sets an indicator 2 in a designated area 12 of the reactor 1. The objective phenomenon of color change of the indicator 2 indicates the reaction endpoint of the nitrogen fertilizer sample and concentrated sulfuric acid, thereby improving the objectivity and accuracy of endpoint determination. At the same time, an absorber 3 is set at the opening 11 of the reactor 1 to neutralize and absorb the acid mist volatilized from the remaining concentrated sulfuric acid after the internal reaction, preventing it from volatilizing into the air and causing pollution. It also enables the reactor 1 to carry out the determination experiment in a normal environment without being limited by the reaction environment, thereby improving its environmental adaptability and detection efficiency.
[0047] The reactor 1 is a rigid structure that provides reaction space for the reaction between the nitrogen fertilizer sample and concentrated sulfuric acid. Reactor 1 can be, but is not limited to, made of glass, which is resistant to high temperatures and strong acids and alkalis, allowing it to be heated. When using the reactor in this embodiment to determine the total nitrogen of compound fertilizer, reactor 1 can be directly heated to accelerate the reaction rate between the nitrogen fertilizer sample and concentrated sulfuric acid. Heating methods can be, but are not limited to, electric furnaces, induction cookers, open flames, etc. For example, when using an electric furnace, the heating temperature can reach 1000 degrees Celsius, which significantly shortens the reaction time and increases the detection rate compared to the 400 degrees Celsius required for the Kjeldahl method using a digestion furnace. The shape of reactor 1 in this embodiment can be designed and adjusted according to actual conditions, and can be, but is not limited to, cup-shaped, barrel-shaped, conical, spherical, etc. It has an opening 11 at the top, the shape and size of which are not limited and can be designed and adjusted according to actual needs. Opening 11 serves as the feeding channel for the nitrogen fertilizer sample and concentrated sulfuric acid, and the placement and removal of the indicator 2 also need to be achieved through opening 11. In this embodiment, at least the designated area 12 with the opening 11 facing downward can be set to be transparent, which can be, but is not limited to, colorless and transparent, so as to facilitate the observation of the color change of the indicator 2. It is easy to understand that the designated area 12 can be the middle part or the middle part upward in the height direction of the reactor 1, so that when the indicator 2 is set in this area, it will not come into contact with the nitrogen fertilizer sample and concentrated sulfuric acid below, thus avoiding the timing of the color change being incorrect.
[0048] The indicator 2 can be a structure containing thymol blue indicator. The indicator 2 can be a sheet or thin plate structure of any shape, such as strip, block, or circle, and can be detachably installed on the inner wall of the designated area 12 by adhesive bonding. For compound fertilizers, the total nitrogen determination requires a complete reaction between the nitrogen fertilizer sample and concentrated sulfuric acid to extract the nitrogen from the compound fertilizer and calculate its nitrogen content. Specifically, the initial stage of the determination involves adding the nitrogen fertilizer sample to reactor 1. The nitrogen fertilizer sample simultaneously contains urea, organic heterocyclic -N (-NH-, -NH2), and NH4+. + (ammonium salt), NO3- (Nitrogen) and a small amount of NO2 - Subsequently, concentrated sulfuric acid was added (T = 0 min). Upon contact with the sample, concentrated H2SO4 immediately caused two things to happen:
[0049] a) Physical dissolution: NH4 in nitrogen fertilizer samples + K + Ca 2+ The inorganic salts dissolve rapidly;
[0050] b) Protonation: All basic nitrogen in the nitrogen fertilizer sample is protonated by H+. + Protonation, forming protonated amine salt R-NH3 + HSO4 - The system is kept in a strong acid pH << 0. Indicator 2 is acidic because thymol blue is red, which is the first color state, indicating acidity.
[0051] Next, the reaction proceeds at a specified temperature for a period of time until the dehydration and carbonization stage (0–3 min, T≈160–180 °C). The concentrated sulfuric acid undergoes dehydration and is diluted to a certain extent, but the acidity does not drop sharply and is still far from enough to trigger the thymol blue color change in indicator 2.
[0052] Continued heating brings the reaction to the deep oxidation stage (3–8 min, T≈200–220 °C, K2SO4 increases boiling point); concentrated sulfuric acid itself acts as an oxidant in reactor 1, causing a redox chain reaction that breaks the CN bonds of organic nitrogen, and nitrogen is successively oxidized to form NH4. + Nitrate nitrogen (NO3) - It is first reduced to NO2 by sulfuric acid. + It is then reduced to NH4 by excess SO2. + .
[0053] At the reaction endpoint, the thymol blue in indicator 2 turns yellow;
[0054] When all nitrogen-containing substances have been converted into ammonium sulfate, the concentration of ammonium sulfate in the system reaches a very high level. Its common ion effect leads to a significant reduction in the activity of free sulfuric acid. This causes the acidity of the local microenvironment to drop sufficiently to change thymol blue (pKa≈1.2) from its acidic form, i.e., the first color state red, to its basic form, i.e., the second color state yellow, thus indicating that the endpoint has been reached.
[0055] Finally, during the heat preservation verification stage (8–12 min), continue heating for 1–2 min. If the color of indicator 2 no longer recovers, it proves that there is no new oxidation reaction and all nitrogen exists in the form of (NH4)2SO4. At this point, it can be considered that the digestion has truly reached its endpoint, and the subsequent steps can be carried out.
[0056] Accordingly, the amount of concentrated sulfuric acid used is not a limitation required by this application, as it is easily understood and operated by those skilled in the art. For example, the acid amount is defined as the situation where more than half of the free sulfuric acid remains after completely oxidizing "all nitrogen + all organic carbon + other oxidizable substances".
[0057] The following calculations are based on empirical formulas commonly used in Kjeldahl / compound fertilizers:
[0058] First, estimate based on nitrogen:
[0059] Each 1g of nitrogen requires 10mL of concentrated H2SO4 (18mol L-1);
[0060] Then correct by organic carbon:
[0061] Compound fertilizers have a low organic C content (3–15%), with an empirical coefficient of 0.5–1.0 mL acid / 1% organic C;
[0062] Minimum safety margin:
[0063] The final residual acid concentration is ≥8 mol L⁻¹ (≈45% H₂SO₄), which translates to a volumetric residual of ≥3 mL.
[0064] "Sample weight × 10 = mL of acid (minimum 2 mL, maximum 25 mL)";
[0065] Therefore, it can be concluded that 0.3g of nitrogen fertilizer sample can be injected with 3mL of concentrated sulfuric acid; 1.5g of nitrogen fertilizer can be injected with 15mL of acid.
[0066] The absorber 3 can be a structural component containing alkaline solution. It can, but is not limited to, having an absorbent material structure inside the absorber 3 to contain the alkaline solution, such as absorbent cotton or a sponge. The absorber 3 can be detachably connected to the opening 11 of the reactor 1, using methods such as, but not limited to, sleeve connections, snap-fit connections, or screw connections. The absorber 3 can be a rigid or flexible structure, as long as it can stably contain the alkaline solution. The shape of the absorber 3 is not limited; it can be spherical, rectangular, hemispherical, conical, or any other shape, as long as it has sufficient space to contain the alkaline solution. It is easy to understand that the material of the absorber 3 needs to have acid and alkali resistance and high-temperature resistance; it can, but is not limited to, rubber, silicone, etc. After the nitrogen fertilizer sample and concentrated sulfuric acid are injected into reactor 1, absorber 3 can be installed at opening 11. Alternatively, absorber 3 can be installed at opening 11 after indicator 2 changes color. After the digestion reaction in reactor 1 is completed, excess concentrated sulfuric acid will volatilize and move towards opening 11. Due to the high temperature of the reaction and heating in reactor 1, the concentrated sulfuric acid volatilizes into an acid mist state, which is cooled, condensed, and refluxed back into reactor 1 after entering absorber 3. Excess gaseous concentrated sulfuric acid will be neutralized and absorbed by the alkaline solution in absorber 3.
[0067] As described above, the compound fertilizer total nitrogen determination device provided in this application directly utilizes reactor 1 to react nitrogen fertilizer samples with concentrated sulfuric acid, replacing specialized equipment, reducing costs and operational difficulty. Furthermore, the objective phenomenon of color change in indicator 2 provides rapid and clear indication of the reaction endpoint, greatly improving the accuracy of endpoint determination and further enhancing the accuracy of the determination results. Simultaneously, the absorber 3 absorbs excess concentrated sulfuric acid in reactor 1, preventing its volatilization and air pollution, and reducing environmental limitations for the determination reaction, enabling determination even under ordinary conditions, thus improving determination efficiency. This solves the technical problem of low accuracy in determining the digestion endpoint during the determination of total nitrogen content in compound fertilizers in existing technologies.
[0068] Further, see attached document. Figure 1 and attached Figure 2 In the specific implementation of the compound fertilizer total nitrogen determination device provided in this embodiment, the reactor 1 further includes a reaction zone 13; the reaction zone 13 is placed on the side of the designated area 12 away from the opening 11, the reaction zone 13 is connected to the designated area 12, and the reaction zone 13 is used to contain nitrogen fertilizer samples and concentrated sulfuric acid; the size of the reaction zone 13 gradually decreases from the opening 11.
[0069] It is understood that, in order to improve the indicating effect of indicator 2, in this embodiment, reactor 1 is divided into three areas from top to bottom: opening area 11, designated area 12, and reaction area 13. This ensures that indicator 2 has a clear and fixed position when it is used with reactor 1, preventing indicator 2 from prematurely contacting the reactants and affecting the timing of the endpoint indication. It is also understood that the position of indicator 2 within designated area 12 is not fixed and can be adjusted according to actual needs and installation conditions; this is not limited here. In this embodiment, the three areas can be without clear boundaries, or they can be divided according to the amount of reactants contained. For example, reaction area 13 can be 2 / 3 of the height of reactor 1, and designated area 12 and opening area 11 can occupy 1 / 3 of the height of reactor 1. In this embodiment, reactor 1 can be a one-piece molded glass bottle, which can be conical to make the size of opening 11 smaller, such as a triangular flask. The narrowing diameter at the top allows concentrated sulfuric acid mist to move upwards within a smaller bottle size space, increasing its contact opportunity with indicator 2, improving the accuracy of the digestion endpoint indication, and avoiding delays.
[0070] Further, see attached document. Figure 3 In the total nitrogen determination device for compound fertilizer provided in this embodiment, the indicator 2 is continuously arranged around the opening 11 for one full cycle.
[0071] Understandably, to improve the indicating effect, in this embodiment, the indicator 2 can be arranged in a continuous loop around the opening 11. This can be achieved by multiple indicators 2 joined together around the loop, or by a single indicator 2 directly looping around the loop, making the color change of the indicator 2 more clearly and obviously detectable. In this embodiment, the thickness of the indicator 2 can also be set to a maximum of 0.5mm, such as 0.2mm, 0.3mm, etc., so that the color change of the indicator 2 can be observed promptly from outside the reactor 1. This prevents the problem that a larger thickness of the indicator 2 may only cause color changes near the inside of the reactor 1, making it difficult to observe and affecting the judgment of experimental results.
[0072] Furthermore, in the specific implementation of the compound fertilizer total nitrogen determination device provided in this embodiment, the indicator 2 includes ceramic fiber and target indicator; the target indicator completely impregnates the ceramic fiber and is air-dried to display the first color state.
[0073] Understandably, in order to achieve the aforementioned color change indication function of indicator 2 with acidity variation, in this embodiment, indicator 2 can be configured to include ceramic fiber and target indicator. It is easy to understand that the target indicator can be thymol blue. Ceramic fiber has a porous structure, which can stably impregnate and contain thymol blue, and increase the contact area between thymol blue and concentrated sulfuric acid mist. In addition, ceramic fiber is heat-insulating, so when the digestion reaction is carried out in reactor 1, the temperature of ceramic fiber can be 80 to 100 degrees lower than the temperature of the reactants or the temperature inside reactor 1, preventing thymol blue from being decomposed and affecting the indication effect. In this embodiment, indicator 2 can be formed by completely impregnating ceramic fiber with 0.1% thymol blue ethanol solution and then air-drying it. When the indicator 2 is installed in conjunction with the reactor 1, it can be bonded by means of adhesive, for example, by setting double-sided adhesive on one side of the surface of the indicator 2. When an experimental test is required, the indicator 2 can be bonded to the designated area of the reactor 1. After the experimental reaction is completed, the indicator 2 can be removed directly by brushing with water flow or by hand. A new indicator 2 can be replaced for the next experimental test.
[0074] Further, see attached document. Figure 2 and attached Figure 3 In the specific implementation of the compound fertilizer total nitrogen determination device provided in this embodiment, the absorber 3 includes an absorption hood 31 and a neutralizing element 32; the absorption hood 31 has a second accommodating space for accommodating the neutralizing element 32, the absorption hood 31 has a second opening 33, the second opening 33 connects the inside and outside of the second accommodating space, and the second opening 33 is used to detachably connect to the opening 11; the neutralizing element 32 is detachably disposed in the second accommodating space, and the neutralizing element 32 is used to absorb and neutralize the acid mist.
[0075] Understandably, to ensure the stable containment of the alkaline solution by the absorber 3, in this embodiment, the absorber 3 is configured to include an absorption cover 31 and a neutralizing element 32. The absorption cover 31, as the structure forming the second containment space, can be a rigid or flexible structure. In this embodiment, it can be, but is not limited to, a hemispherical hollow structure. It can be modified using a suction bulb, for example, by cutting off a portion of the spherical air bladder along with the slender conduit, leaving the remaining spherical air bladder. The cut-off end of the spherical air bladder then becomes the second opening 33. The second opening 33 can then be detachably connected to the opening 11 using its own elasticity and deformability. The absorption cover 31 can also be a combination of rigid and elastic structures, for example, the second opening 33 can be elastic, while the rest can be rigid, to facilitate the detachable connection of the second opening 33 and the opening 11 and improve the ease of connection. The neutralizing element 32 can be a structure capable of containing or wetting the alkaline solution.
[0076] Furthermore, in the specific implementation of the compound fertilizer total nitrogen determination device provided in this embodiment, the neutralizing element 32 includes an absorber and a neutralizing reagent; the absorber is absorbent and flexible to deform when passing through the second opening 33; the neutralizing reagent wets the absorber for neutralizing the acid mist.
[0077] Understandably, in order to enable the neutralizing element 32 to contain or be soaked in alkaline solution and to be detachable within the second containment space, this embodiment can be configured to include an absorbent and a neutralizing reagent. The absorbent needs to be absorbent and flexible, thus enabling it to both contain and soak the neutralizing reagent and deform when entering and exiting the second opening 33. It can be, but is not limited to, absorbent cotton. The absorbent cotton, saturated with alkaline solution, can be squeezed and deformed at the second opening 33 to enter and remain within the second containment space. Similarly, it can be removed by clamping it with tweezers or other tools and pulling it out of the second opening 33. Correspondingly, the neutralizing reagent can be, but is not limited to, alkaline solution, such as 0.1 mol L⁻¹ NaOH or saturated NaHCO₃, etc.
[0078] Further, see attached document. Figure 2 In the compound fertilizer total nitrogen measuring device provided in this embodiment, in a specific implementation, at least one protrusion 34 is provided on the circumferential inner wall of the second opening 33, and the protrusion 34 is used to abut against the outer wall of the opening 11.
[0079] Understandably, to improve the fit between the second opening 33 and the opening 11, at least one protrusion 34 can be provided on the circumferential inner wall of the second opening 33 in this embodiment. The protrusion 34 can be integrally formed with the absorption cover 31, and the protrusion 34 can be elastic, thereby maintaining a pre-tightening force under the compression of the outer wall of the absorption cover 31 and the outer wall of the opening 11, improving the sealing and tightness of the fit between the two openings. This not only improves the fit between the two openings but also reduces the occurrence of internal acid mist leakage. The number of protrusions 34 can be designed and adjusted according to actual needs. Multiple protrusions 34 can be arranged at intervals in the direction away from the opening 11 to increase the contact area and sealing performance.
[0080] Example 2
[0081] This embodiment provides a total nitrogen determination system for compound fertilizer, which includes at least one total nitrogen determination device for compound fertilizer. The total nitrogen determination device for compound fertilizer includes a reactor 1, an indicator 2, and an absorber 3. The reactor 1 has a containment space for containing nitrogen fertilizer samples and concentrated sulfuric acid. The top of the reactor 1 is provided with an opening 11 to connect the inside and outside of the containment space. At least the designated area 12 of the reactor 1 facing downward from the opening 11 is transparent. The indicator 2 is detachably disposed on the inner wall of the designated area 12. The indicator 2 has a first color state and a second color state. After the reaction between the nitrogen fertilizer sample and concentrated sulfuric acid is completed, the indicator 2 can change from the first color state to the second color state. The absorber 3 is detachably disposed on the opening 11. The absorber 3 is used to absorb the acid mist volatilized from the concentrated sulfuric acid in the containment space.
[0082] It is understood that the compound fertilizer total nitrogen measuring device provided in this embodiment is the same as the compound fertilizer total nitrogen measuring device described in Embodiment 1. For its detailed structure and working principle, please refer to the detailed description of Embodiment 1, which will not be repeated here.
[0083] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A device for determining total nitrogen in compound fertilizer, characterized in that, It includes: A reactor having a containment space for containing nitrogen fertilizer samples and concentrated sulfuric acid, the top of the reactor having an opening to connect the inside and outside of the containment space, and at least a designated area of the reactor facing downwards from the opening being transparent; An indicator is detachably mounted on the inner wall of the designated area, and the indicator has a first color state and a second color state; the indicator changes from the first color state to the second color state after the reaction between the nitrogen fertilizer sample and concentrated sulfuric acid is completed. An absorber, detachably disposed at the opening, is used to absorb acid mist emitted from concentrated sulfuric acid within the containment space.
2. The compound fertilizer total nitrogen determination device according to claim 1, characterized in that: The reactor also includes a reaction zone; The reaction zone is located on the side of the designated area away from the opening, and the reaction zone is connected to the designated area. The reaction zone is used to contain nitrogen fertilizer samples and concentrated sulfuric acid. The size of the reaction region gradually decreases from the opening.
3. The compound fertilizer total nitrogen determination device according to claim 1, characterized in that: The indicator is continuously arranged around the opening for one revolution.
4. The compound fertilizer total nitrogen determination device according to claim 1, characterized in that: The indicator comprises ceramic fibers and a target indicator; The target indicator is completely impregnated with the ceramic fiber and air-dried to reveal the first color state.
5. The compound fertilizer total nitrogen determination device according to claim 1 or 4, characterized in that: The thickness of the indicator is at most 0.5 mm.
6. The compound fertilizer total nitrogen determination device according to claim 1, characterized in that: The absorber includes an absorption hood and a neutralizing element; The absorption cover has a second receiving space for accommodating the neutralizing component, and the absorption cover has a second opening that connects the inside and outside of the second receiving space. The second opening is detachably connected to the opening. The neutralizing element is detachably disposed within the second accommodating space, and the neutralizing element is used to absorb and neutralize the acid mist.
7. The compound fertilizer total nitrogen determination device according to claim 6, characterized in that: The absorption cover is elastic at least at the second opening.
8. The compound fertilizer total nitrogen determination device according to claim 6, characterized in that: The neutralizing element includes an absorber and a neutralizing agent; The absorbent is absorbent and flexible, so as to deform when passing through the second opening; The neutralizing agent wets the absorber for neutralizing the acid mist.
9. The compound fertilizer total nitrogen determination device according to claim 6, characterized in that: The second opening has at least one protrusion on its circumferential inner wall, the protrusion being used to abut against the outer wall of the opening.
10. A system for determining total nitrogen in compound fertilizers, characterized in that, It includes: At least one compound fertilizer total nitrogen determination device, comprising: A reactor having a containment space for containing nitrogen fertilizer samples and concentrated sulfuric acid, the top of the reactor having an opening to connect the inside and outside of the containment space, and at least a designated area of the reactor facing downwards from the opening being transparent; An indicator is detachably mounted on the inner wall of the designated area, and the indicator has a first color state and a second color state; the indicator changes from the first color state to the second color state after the reaction between the nitrogen fertilizer sample and concentrated sulfuric acid is completed. An absorber, detachably disposed at the opening, is used to absorb acid mist emitted from concentrated sulfuric acid within the containment space.