COD (Chemical Oxygen Demand) testing system and testing method based on COD testing system

Abstract

The invention discloses a COD testing system and a testing method based on the COD testing system.The COD testing system comprises a digestion detection unit and a backflow detection unit, the digestion detection unit comprises a heating kettle, a volumetric flask and a heating part, the volumetric flask is arranged in the heating kettle and used for containing original reaction liquid, the heating part is arranged in the heating kettle and used for heating the volumetric flask, and the heating part is used for heating the original reaction liquid; the reflux detection unit comprises a condensation pipe and a reflux vessel, one end of the condensation pipe is connected with the opening of the volumetric flask, the reflux vessel is communicated with the other end of the condensation pipe and is used for recovering condensate, and the original reaction liquid and the condensate are both used as COD test liquid. According to the COD testing system, the part lost by evaporation can be recycled in the form of condensate, then COD testing is performed on the original reaction liquid and the recycled condensate respectively, and an accurate testing value can be obtained after detection data is summarized, so that the problem of testing errors caused by evaporation of the testing liquid can be avoided, and the accuracy of a testing result is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical analysis, in particular to a COD testing system and a testing method based on the COD testing system. Background Art

[0002] Chemical oxygen demand (COD) is the amount of oxidant consumed when a water sample is treated with a certain strong oxidant under certain conditions. It is an important indicator of the amount of reducing substances in water. In the relevant technology, the potassium permanganate method is a commonly used COD test method. However, when the potassium permanganate method is used in practice, there is a problem of inaccurate test results due to evaporation loss of the reaction solution. Therefore, how to solve this systematic error has become a key issue in improving detection accuracy. Summary of the invention

[0003] The technical problem to be solved by the present invention is that, in view of the defects and shortcomings of the prior art, a COD testing system is proposed. Compared with the traditional scheme, the system has a new reflux detection unit, which can recover the part lost by evaporation in the form of condensate, and then perform COD tests on the original reaction liquid and the recovered condensate respectively. After the test data are summarized, an accurate test value can be obtained, thereby avoiding the test error problem caused by evaporation of the test liquid and ensuring the accuracy of the test results.

[0004] The COD testing system of an embodiment of the present invention includes a digestion detection unit and a reflux detection unit, the digestion detection unit includes a heating kettle, a volumetric flask, and a heating element, the volumetric flask is arranged in the heating kettle and is used to contain the original reaction liquid, the heating element is arranged in the heating kettle to heat the volumetric flask, the reflux detection unit includes a condenser and a reflux dish, one end of the condenser is connected to the opening of the volumetric flask, the reflux dish is connected to the other end of the condenser and is used to recover the condensate, the original reaction liquid and the condensate are both used as COD test liquid.

[0005] The COD testing system of the embodiment of the present invention comprises a digestion detection unit including a heating kettle, a volumetric flask, and a heating element. The volumetric flask is arranged in the heating kettle and is used to accommodate the original reaction liquid. The heating element is arranged in the heating kettle and is used to heat the volumetric flask. The reflux detection unit comprises a condenser and a reflux dish. One end of the condenser is connected to the opening of the volumetric flask, and the reflux dish is connected to the other end of the condenser and is used to recover the condensate. Both the original reaction liquid and the condensate are used as COD test liquids. Therefore, compared with the traditional scheme, the system is newly provided with a reflux detection unit, which can recover the part lost by evaporation in the form of condensate, and then perform COD tests on the original reaction liquid and the recovered condensate respectively. After the detection data are summarized, accurate test values ​​can be obtained, thereby avoiding the test error problem caused by the evaporation of the test liquid and ensuring the accuracy of the test results.

[0006] In some embodiments, the COD testing system further includes a cooling unit, wherein the cooling unit includes a first cooling module, and the first cooling module is used to cool the condenser tube.

[0007] In some embodiments, the cooling unit further includes a second cooling module, and the second cooling module is used to cool the reflux dish.

[0008] In some embodiments, the first cooling module and / or the second cooling module comprises a sealed box and a fan, the sealed box is sealed and covered on the outer wall of the condenser and / or the reflux dish, and the fan is arranged in the sealed box.

[0009] In some embodiments, the condenser includes a cooling tube, an inclined flow tube and a reflux tube. The cooling tube is vertically connected to the upper opening of the volumetric flask, the reflux tube is vertically arranged and its lower end is inserted into the reflux dish, and the inclined flow tube is connected between the upper end of the cooling tube and the upper end of the reflux tube.

[0010] In some embodiments, the inclined flow pipe is arranged to be inclined downward in a direction from the cooling pipe to the return pipe.

[0011] In some embodiments, the first cooling module is used to cool the cooling pipe.

[0012] In some embodiments, a reaction ball is provided at the lower end of the reflux pipe, and the reaction ball is provided with a plurality of air flow holes connected to the reflux pipe.

[0013] In some embodiments, the reflux dish is a closed container, and an exhaust pipe communicating with the outside is provided on the top plate of the reflux dish.

[0014] The testing method based on the COD testing system of the embodiment of the present invention, wherein the COD testing system is the COD testing system described in the above embodiment, comprises:

[0015] Heating the volumetric flask for a predetermined time;

[0016] Collect the reaction liquid in the volumetric flask as the first group of test liquids, and collect the condensate in the reflux dish as the second group of test liquids;

[0017] The COD test was performed on the first group of test liquids and the second group of test liquids respectively, and the two groups of test data were summarized.

[0018] The testing method based on the COD testing system of the embodiment of the present invention can summarize the accurate value of the COD test by testing two groups of data, the reaction liquid in the volumetric flask and the condensate in the reflux dish, thereby solving the detection error caused by evaporation loss in the traditional method. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of the COD testing system according to an embodiment of the present invention.

[0020] Figure 2 Schematic diagram of the structure of the reaction ball of the COD testing system according to the embodiment of the present invention.

[0021] Reference numerals:

[0022] Heating kettle 1, heating element 2, volumetric flask 3, reaction liquid 4, cooling tube 5, first cooling module 6, diagonal flow tube 7, reflux tube 8, reaction ball 9, air flow hole 101, exhaust pipe 10, condensate 11, first cooling module 12. DETAILED DESCRIPTION

[0023] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0024] like Figure 1 As shown, the COD testing system of the embodiment of the present invention includes a digestion detection unit and a reflux detection unit, the digestion detection unit includes a heating kettle 1, a volumetric flask 3, and a heating element 2, the volumetric flask 3 is arranged in the heating kettle 1 and is used to accommodate the original reaction liquid 4, the heating element 2 is arranged in the heating kettle 1 for heating the volumetric flask 3, the reflux detection unit includes a condenser and a reflux dish, one end of the condenser is connected to the opening of the volumetric flask 3, the reflux dish is connected to the other end of the condenser and is used to recover the condensate 11, the original reaction liquid 4 and the condensate 11 are both used as COD test liquids.

[0025] It is understandable that, in COD testing rooms such as the potassium permanganate method, when the traditional testing system heats the reaction liquid 4, part of the reaction liquid 4 will evaporate and be lost, and the evaporated part will be ignored when testing the original reaction liquid 4, resulting in the test result being smaller than the accurate value. The present application adds a reflux detection unit to the original system, and uses a reflux dish to collect the evaporated part, and the collected condensate 11 and the original reaction liquid 4 are both tested. After the test data are summarized, an accurate test value can be obtained, thereby avoiding the test error problem caused by the evaporation of the test liquid.

[0026] The COD testing system of the embodiment of the present invention comprises a digestion detection unit including a heating kettle 1, a volumetric flask 3, and a heating element 2. The volumetric flask 3 is arranged in the heating kettle 1 and is used to accommodate the original reaction liquid 4. The heating element 2 is arranged in the heating kettle 1 and is used to heat the volumetric flask 3. The reflux detection unit comprises a condenser and a reflux dish. One end of the condenser is connected to the opening of the volumetric flask 3. The reflux dish is connected to the other end of the condenser and is used to recover the condensate 11. The original reaction liquid 4 and the condensate 11 are both used as COD test liquids. Therefore, compared with the traditional scheme, the system is newly provided with a reflux detection unit, which can recover the part lost by evaporation in the form of condensate 11, and then the original reaction liquid 4 and the recovered condensate 11 are respectively tested for COD. After the test data are summarized, an accurate test value can be obtained, thereby avoiding the test error problem caused by the evaporation of the test liquid and ensuring the accuracy of the test results.

[0027] In some embodiments, the COD test system further includes a cooling unit, which includes a first cooling module 6, and the first cooling module 6 is used to cool the condenser tube. Thus, the first cooling module 6 can improve the condensation effect of the condenser tube, and make the evaporated gas flow into the recovery dish in the form of condensate 11 as much as possible, thereby improving the test accuracy.

[0028] Furthermore, the cooling unit also includes a second cooling module 12, and the second cooling module 12 is used to cool the reflux dish. It should be noted that the steam generated by heating and evaporating the reaction liquid 4 usually flows into the reflux dish in the form of a gas-liquid mixture after being cooled by the condenser, and the second cooling module 12 can further cool the steam in the reflux dish to ensure that the evaporated part can eventually be completely stored in the reflux dish in a liquid form to ensure the test accuracy.

[0029] In some embodiments, the first cooling module 6 and / or the second cooling module 12 include a sealed box and a fan, the sealed box is sealed and coated on the outer wall of the condenser and / or the reflux dish, and the fan is arranged in the sealed box. In other words, the cooling unit is cooled in the form of air cooling. It should be noted that the traditional solution usually adopts the method of external cooling water. Compared with the traditional solution, the present application does not need external cooling water, is simple and easy to operate, and optimizes the system structure.

[0030] In some embodiments, the condenser includes a cooling tube 5, an oblique flow tube 7 and a reflux tube 8, the cooling tube 5 is vertically connected to the upper opening of the volumetric flask 3, the reflux tube 8 is vertically arranged and its lower end is inserted into the reflux dish, and the oblique flow tube 7 is connected between the upper end of the cooling tube 5 and the upper end of the reflux tube 8. It can be understood that the steam generated by heating and evaporating the reaction liquid 4 in the volumetric flask 3 flows along the cooling tube 5, the oblique flow tube 7 and the reflux tube 8, part of the steam condenses in the cooling tube 5 and directly flows back to the volumetric flask 3, and the remaining steam is cooled at the oblique flow tube 7 and the reflux tube 8 and finally flows into the reflux dish.

[0031] Preferably, the inclined flow tube 7 is arranged to be tilted downward from the cooling tube 5 to the return tube 8. Thus, the inclined inclined flow tube 7 can allow the condensate 11 to flow smoothly into the subsequent return tube 8 and finally be received by the return dish, thereby preventing the condensate 11 from being retained in the inclined flow tube 7 and ensuring the test accuracy.

[0032] Furthermore, the first cooling module 6 is used to cool the cooling pipe 5 .

[0033] In some embodiments, Figure 1 and Figure 2 As shown, a reaction ball 9 is provided at the lower end of the reflux pipe 8, and a plurality of airflow holes 101 are provided on the reaction ball 9 and are connected to the reflux pipe 8. It can be understood that the plurality of airflow holes 101 can disperse the uncondensed steam in the reflux pipe 8 into a plurality of small airflows, so that the subsequent gas can be fully integrated into the condensate 11 in the reflux dish after flowing out, avoiding overflow in the form of bubbles, thereby ensuring the test accuracy.

[0034] Furthermore, if Figure 1 As shown, the reflux dish is a closed dish, and an exhaust pipe 10 connected to the outside is provided on the top plate of the reflux dish. Thus, the closed dish can prevent the condensate 11 from escaping, ensuring the test accuracy, and the exhaust pipe 10 can balance the pressure inside and outside the reflux dish.

[0035] The testing method based on the COD testing system of the embodiment of the present invention, the COD testing system is the COD testing system of the above embodiment, and the testing method includes: heating the volumetric flask 3 to a predetermined time; collecting the reaction liquid 4 in the volumetric flask 3 as the first group of test liquids, and collecting the condensate 11 in the reflux dish as the second group of test liquids; performing COD tests on the first group of test liquids and the second group of test liquids respectively, and summarizing the two groups of test data.

[0036] The testing method based on the COD testing system of the embodiment of the present invention can summarize the accurate value of the COD test by testing two groups of data, the reaction liquid 4 in the volumetric flask 3 and the condensate 11 in the reflux dish, thereby solving the detection error caused by evaporation loss in the traditional method.

[0037] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0041] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0042] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A COD testing system, characterized in that: It includes a digestion detection unit and a reflux detection unit. The digestion detection unit includes a heating kettle, a volumetric flask, and a heating element. The volumetric flask is arranged in the heating kettle and is used to contain the original reaction liquid. The heating element is arranged in the heating kettle and is used to heat the volumetric flask. The reflux detection unit includes a condenser and a reflux dish. One end of the condenser is connected to the opening of the volumetric flask, and the reflux dish is connected to the other end of the condenser and is used to recover the condensate. The original reaction liquid and the condensate are both used as COD test liquids.

2. The COD testing system according to claim 1, characterized in that: It also includes a cooling unit, which includes a first cooling module, and the first cooling module is used to cool the condenser.

3. The COD testing system according to claim 2, characterized in that: The cooling unit further includes a second cooling module, and the second cooling module is used to cool the reflux dish.

4. The COD testing system according to claim 3, characterized in that: The first cooling module and / or the second cooling module comprises a sealed box and a fan. The sealed box is sealed and covered on the outer wall of the condenser and / or the reflux dish. The fan is arranged in the sealed box.

5. The COD testing system according to claim 2, characterized in that: The condenser includes a cooling tube, an oblique flow tube and a reflux tube. The cooling tube is vertically connected to the upper opening of the volumetric flask. The reflux tube is vertically arranged and its lower end is inserted into the reflux dish. The oblique flow tube is connected between the upper end of the cooling tube and the upper end of the reflux tube.

6. The COD testing system according to claim 5, characterized in that: The inclined flow pipe is arranged to be inclined downward in a direction from the cooling pipe to the return pipe.

7. The COD testing system according to claim 5, characterized in that: The first cooling module is used to cool the cooling pipe.

8. The COD testing system according to claim 5, characterized in that: A reaction ball is arranged at the lower end of the reflux pipe, and a plurality of air flow holes communicating with the reflux pipe are arranged on the reaction ball.

9. The COD testing system according to claim 1, characterized in that: The reflux dish is a closed container, and an exhaust pipe communicating with the outside is arranged on the top plate of the reflux dish.

10. A testing method based on a COD testing system, characterized in that: The COD testing system is a COD testing system according to any one of claims 1 to 9, and the testing method comprises: Heating the volumetric flask for a predetermined time; Collect the reaction liquid in the volumetric flask as the first group of test liquids, and collect the condensate in the reflux dish as the second group of test liquids; The COD test was performed on the first group of test liquids and the second group of test liquids respectively, and the two groups of test data were summarized.

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