A device for detecting the formaldehyde content in polyoxymethylene particles

Abstract

The application provides a device for detecting formaldehyde content in polyformaldehyde particles, which comprises a polyformaldehyde hot melting assembly and a formaldehyde detection assembly; the polyformaldehyde hot melting assembly comprises a polyformaldehyde melting cavity and a gas collector; the gas collector is arranged below the polyformaldehyde melting cavity; the polyformaldehyde melting cavity and the gas collector are in spatial communication through a melt pipeline; the formaldehyde detection assembly comprises a formaldehyde sensor and a gas circulation member; the formaldehyde sensor is arranged inside the gas circulation member; a gas inlet of the gas circulation member and a gas outlet of the gas collector are in spatial communication; and the gas outlet of the gas circulation member and the gas inlet of the gas collector are in spatial communication. By arranging the gas circulation communication between the polyformaldehyde hot melting assembly and the formaldehyde detection assembly, the application realizes rapid detection of the formaldehyde content in the polyformaldehyde particles, and the detection result has high accuracy.

Description

Technical Field

[0001] This utility model relates to the field of energy and chemical technology, and in particular to a device for detecting the formaldehyde content in polyoxymethylene particles. Background Technology

[0002] Free formaldehyde in polyoxymethylene (POM) products is a toxic gas with a strong, pungent odor. If the free formaldehyde content in POM products exceeds the standard, it can seriously endanger human health during production and processing. Therefore, determining the content of free gaseous formaldehyde in POM is crucial. Furthermore, the results of gaseous formaldehyde content determination during production directly affect the pass rate of POM products. Thus, determining the content of free gaseous formaldehyde is also a critical factor in production cost and operational control.

[0003] Currently, there is no unified standard for determining gaseous formaldehyde in polyoxymethylene (POM). The formaldehyde release from POM affects downstream processing and applications, and there is a pressing need for methods to quickly test the formaldehyde release of POM before it leaves the factory. Some companies refer to the German Association of the Automotive Industry (DA) standard VDA 275 (Determination of Formaldehyde from Vehicle Interior with Modified Flask Method VDA 275) to determine the formaldehyde content in finished POM (Polyoxymethylene). The testing principle involves injection molding POM into square sheets, which are then suspended in a sealed PTFE bottle containing distilled water and kept at 60°C for 3 hours. The water absorption solution is then subjected to color development, and the formaldehyde content in the sample is determined using a spectrophotometer. VDA 275 is used in automotive interior textiles and is mainly for testing molded materials. However, its absorption time is long (up to 3 hours), making it difficult to detect formaldehyde gas generated during the production and processing of finished POM granules, and thus it cannot meet the needs of actual production testing.

[0004] Patent CN105498454A designs a collection device that completely collects gaseous formaldehyde from the surface and interior of the polyoxymethylene (POM) by melting it at 190℃ and dissolving the resulting gaseous formaldehyde in water. The water-absorbing solution is then subjected to color development treatment, and the formaldehyde content in the sample is determined by a spectrophotometer. This detection method has the following drawbacks: it requires the preparation of a standard curve and colorimetric reagent; errors can easily occur during solution transfer, affecting the test results; some waste solution is generated during the testing process, potentially causing environmental pollution; the peristaltic pump pumping process causes some formaldehyde gas released from the POM melt to escape from the device, resulting in lower detection data. Because formaldehyde is denser than air, when pumping air from the side of the gaseous formaldehyde collection bottle, some formaldehyde gas will settle at the bottom of the bottle, causing incomplete pumping and inaccurate detection data.

[0005] Therefore, existing technologies for determining gaseous formaldehyde in polyoxymethylene suffer from problems such as long testing times, susceptibility to operational errors during testing, and inaccurate test results. Summary of the Invention

[0006] This application aims to solve the technical problems of slow detection speed and low accuracy of formaldehyde content in polyoxymethylene (POM) particles. To address this problem, the technical solution provided in this application is as follows: This application provides a device for detecting formaldehyde content in polyoxymethylene particles, the device comprising a polyoxymethylene hot-melt assembly and a formaldehyde detection assembly; The polyoxymethylene hot-melt assembly includes a polyoxymethylene melting chamber and a gas collector; the gas collector is located below the polyoxymethylene melting chamber; and the polyoxymethylene melting chamber and the gas collector are connected by a melt pipe space. The formaldehyde detection component includes a formaldehyde sensor and a gas circulation component; the formaldehyde sensor is disposed inside the gas circulation component; the gas inlet of the gas circulation component and the gas outlet of the gas collector are connected in space; the gas outlet of the gas circulation component and the gas inlet of the gas collector are connected in space.

[0007] In some exemplary embodiments, the height of the gas outlet of the gas collector is less than the height of the gas inlet of the gas collector.

[0008] In some exemplary embodiments, the melt conduit is positioned at a first vertical angle between the polyoxymethylene melting chamber and the gas collector.

[0009] In some exemplary embodiments, the polyoxymethylene hot melt assembly further includes a load application element; The load-applying component is positioned above the polyoxymethylene melting cavity and is in communication with the polyoxymethylene melting cavity space.

[0010] In some exemplary embodiments, the polyoxymethylene hot melt assembly further includes a seal; The sealing element is disposed between the polyoxymethylene melting chamber and the gas collector.

[0011] In some exemplary embodiments, the detection device further includes a lifting platform disposed below the gas collector.

[0012] By adopting the above technical solution, the device for detecting formaldehyde content in polyoxymethylene particles provided in this application has the following beneficial effects: This application provides a device for detecting formaldehyde content in polyoxymethylene (POM) particles. The device includes a POM hot-melt assembly and a formaldehyde detection assembly. The POM hot-melt assembly includes a POM melting chamber and a gas collector. The gas collector is located below the POM melting chamber, and the POM melting chamber and the gas collector are spatially connected via a melt pipe. The formaldehyde detection assembly includes a formaldehyde sensor and a gas circulation component. The formaldehyde sensor is located inside the gas circulation component. The gas inlet of the gas circulation component and the gas outlet of the gas collector are spatially connected. The gas outlet of the gas circulation component and the gas inlet of the gas collector are spatially connected. This application achieves rapid detection of formaldehyde content in POM particles with high accuracy by establishing a gas circulation connection between the POM hot-melt assembly and the formaldehyde detection assembly. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a diagram of a device for detecting formaldehyde content in polyoxymethylene particles, provided as an embodiment of this application.

[0015] The following is supplementary explanation of the attached figures: 1-Polyoxymethylene hot melt assembly; 11-Polyoxymethylene melting chamber; 12-Gas collector; 121-Gas outlet of gas collector; 122-Gas inlet of gas collector; 13-Melted pipe; 14-Load application component; 15-Sealing component; 2-Formaldehyde detection assembly; 21-Formaldehyde sensor; 22-Gas circulation component; 221-Gas inlet of gas circulation component; 222-Gas outlet of gas circulation component; 3-Lifting platform; 4-Circulating gas pipeline. Detailed Implementation

[0016] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0017] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0018] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included. For example, a specified range from “1 to 10” should be considered to include any and all subranges between the minimum value 1 and the maximum value 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0019] This application provides a device for detecting formaldehyde content in polyoxymethylene particles. Please refer to [link to relevant documentation]. Figure 1 The detection device includes a polyoxymethylene hot-melt assembly 1 and a formaldehyde detection assembly 2.

[0020] The polyoxymethylene hot melt assembly 1 includes a polyoxymethylene melting chamber 11 and a gas collector 12; the gas collector 12 is located below the polyoxymethylene melting chamber 11; and the polyoxymethylene melting chamber 11 and the gas collector 12 are spatially connected through a melt pipe 13.

[0021] Specifically, the furnace chamber of the melt indexer can be directly selected as the polyoxymethylene melting chamber 11. The polyoxymethylene melting chamber 11 can heat the polyoxymethylene particles to a molten state. The molten polyoxymethylene can flow through the melt pipe 13 to the gas collector 12. The gas collector 12 can then collect the gaseous formaldehyde molecules released by the molten polyoxymethylene entering the gas collector 12.

[0022] The formaldehyde detection component 2 includes a formaldehyde sensor 21 and a gas circulation component 22; the formaldehyde sensor 21 is disposed inside the gas circulation component 22; the gas inlet 221 of the gas circulation component and the gas outlet 121 of the gas collector are spatially connected; the gas outlet 222 of the gas circulation component and the gas inlet 122 of the gas collector are spatially connected.

[0023] Specifically, the formaldehyde detection component 2 can be a formaldehyde detector equipped with an air pump, which serves as a gas circulation component 22. The gas circulation component 22 and the gas collector 12 can be connected via a circulating gas pipeline 4.

[0024] In this embodiment, the height of the gas outlet 121 of the gas collector is less than the height of the gas inlet 122 of the gas collector.

[0025] Specifically, considering that the relative molecular mass of formaldehyde molecules is greater than the average relative molecular mass of air, and to avoid some formaldehyde gas depositing at the bottom of the gas collector 12, the gas outlet 121 of the gas collector can be set at the bottom of the gas collector 12, while the gas inlet 122 of the gas collector can be set at the top of the gas collector 12. This can better realize the circulation of formaldehyde gas and thus improve the accuracy of formaldehyde detection results.

[0026] In this embodiment, the melt pipe 13 is disposed at a first vertical angle between the polyoxymethylene melting chamber 11 and the gas collector 12.

[0027] Specifically, the first vertical angle can be vertically downward or inclined downward at a certain angle, as long as it allows the melt in the melt pipe 13 to flow downward. For example, the melt pipe 13 is vertically downward between the polyoxymethylene melting chamber 11 and the gas collector 12. By setting the direction of the melt pipe 13 to be completely consistent with the direction of gravity of the melt, the melt flows to the gas collector 12 at the fastest speed. For example, the melt pipe 13 is inclined downward at 45 degrees between the polyoxymethylene melting chamber 11 and the gas collector 12. By setting the direction of the melt pipe 13 to form a 45-degree angle with the direction of gravity of the melt, the speed at which the melt flows to the gas collector 12 is slowed, which helps to ensure the complete release of formaldehyde from the polyoxymethylene melt.

[0028] In this embodiment, the polyoxymethylene hot melt assembly 1 further includes a load application member 14; the load application member 14 is disposed above the polyoxymethylene melting cavity 11 and is spatially connected to the polyoxymethylene melting cavity 11.

[0029] Specifically, the function of the load applicator 14 is to apply a load to the polyoxymethylene melting chamber 11. In specific implementations, the load amount of the load applicator 14 can be set according to actual needs. For example, the load amount applied by the load applicator 14 is set to 2.16 kg so that the melt obtained after the polyoxymethylene finished particles are melted flows smoothly into the gas collector 12 through the melt pipe 13.

[0030] In this embodiment, the polyoxymethylene hot melt assembly 1 further includes a sealing element 15; the sealing element 15 is disposed between the polyoxymethylene melting chamber 11 and the gas collector 12.

[0031] Specifically, the seal 15 is disposed between the polyoxymethylene melting chamber 11 and the gas collector 12 to improve the airtightness of the polyoxymethylene hot-melt assembly 1 and prevent formaldehyde gas from escaping. In specific implementations, the material and shape of the seal 15 can be set according to actual needs. For example, a sealing gasket serves as the seal 15.

[0032] In this embodiment of the application, the detection device further includes a lifting platform 3, which is disposed below the gas collector 12.

[0033] In specific implementation, the model and height of the lifting platform 3 can be set according to actual needs. For example, the lifting platform 3 is set below the gas collector 12 so that the height of the polyoxymethylene hot melt assembly 1 is adjustable.

[0034] To facilitate understanding of the technical solutions in the embodiments of this application, the following is combined with... Figure 1 The assembly and use process of a device for detecting formaldehyde content in polyoxymethylene particles according to an embodiment of this application will be described.

[0035] The detection device includes a polyoxymethylene hot-melt assembly 1 and a formaldehyde detection assembly 2; The polyoxymethylene (POM) hot-melt assembly 1 includes a melt indexer and a gas collector 12. The melt indexer includes a POM melting chamber 11. The gas collector 12 is located below the POM melting chamber 11, and the POM melting chamber 11 and the gas collector 12 are spatially connected through a melt pipe 13. A sealing gasket 15, serving as a seal, is disposed between the melt indexer and the gas collector 12. It should be noted that this embodiment does not specifically limit the model of the melt indexer; any commercially available melt indexer capable of melting POM can be selected.

[0036] The melt pipe 13 is arranged vertically downwards between the polyoxymethylene melting chamber 11 and the gas collector 12.

[0037] The formaldehyde detection component 2 is a formaldehyde detector 2 equipped with a vacuum pump. The gas circulation component 22 includes a vacuum pump. The formaldehyde detector 2 is equipped with a formaldehyde sensor 21, which also has a display screen.

[0038] The gas collector 12 is a gas collection bottle (with a volume of 2L). The lower support of the gas collection bottle serves as the gas outlet 121 of the gas collector, and the upper support serves as the gas inlet 122. A lifting platform 3 is also provided below the gas collector 12.

[0039] The gas outlet 121 of the gas collector is connected to the gas inlet 221 of the gas circulation component via the circulating gas pipeline 4; the gas inlet 122 of the gas collector is connected to the gas outlet 222 of the gas circulation component via the circulating gas pipeline 4. The circulating gas pipeline 4 is a rubber hose.

[0040] The polyoxymethylene (POM) granules are melted in the furnace chamber (POM melting chamber 11) of the melt indexer. The production and processing temperature of POM is 170-210℃, preferably 190℃, which is close to the production and processing temperature of POM. A mass of a (g) of POM granules is weighed, and the melting temperature is set at 190℃. After adding the POM granules to the hot-melt device, the piston rod is used to press and vent the gas, and then a load (2.16 kg) is applied to allow the molten POM to flow into the gas collector 12. Since formaldehyde is denser than air, the formaldehyde gas will settle at the bottom of the gas collector 12. The load is mainly to allow the melt obtained after melting the POM granules to flow into the gas collector 12 through the melt pipe 13, facilitating the subsequent collection of gaseous formaldehyde released after the POM granules melt.

[0041] After applying the load, immediately turn on the formaldehyde detector 2 to extract gas. Set the gas flow rate to 300-600 mL / min, preferably 400 mL / min. After 15 minutes, take a reading and record the formaldehyde detector 2's detection data b (unit: μg / dm³). 3 ).

[0042] W (surface formaldehyde release, μg / g) =

[0043] In the formula, W represents the surface formaldehyde release amount, in μg / g; a represents the mass of the finished polyoxymethylene granules, in g; and b represents the formaldehyde detector reading, in ug / dm³. 3 V represents the volume of the gas collection bottle, in liters (L).

[0044] (1) Weigh 5±0.01g of polyoxymethylene finished particles and put them into the furnace chamber (polyoxymethylene melting chamber 11) of the melt indexer. After pressing and venting the air using the piston rod, apply a load (2.16kg) to make the polyoxymethylene melt obtained by melting the polyoxymethylene finished particles flow into the gas collector 12.

[0045] (2) After loading, immediately turn on the formaldehyde detector 11 to circulate the gas collector 12, and set the flow rate to 400 mL / min.

[0046] (3) The entire collection process involves evacuating for 15 minutes.

[0047] (4) Record the formaldehyde detector reading. It should be noted that you only need to record the maximum reading of the formaldehyde detector.

[0048] The above method was used to test the polyoxymethylene finished product. The test results are shown in Table 1. The difference between the parallel test results does not exceed 10% of the lower result.

[0049] Table 1. Test results of formaldehyde gas content in different batches of polyoxymethylene products.

[0050] This application discloses a device for detecting formaldehyde content in polyoxymethylene (POM) particles. The device includes a POM hot-melt assembly and a formaldehyde detection assembly. The POM hot-melt assembly includes a POM melting chamber and a gas collector. The gas collector is located below the POM melting chamber, and the POM melting chamber and the gas collector are connected via a melt pipe. The formaldehyde detection assembly includes a formaldehyde sensor and a gas circulation component. The formaldehyde sensor is located inside the gas circulation component. The gas inlet of the gas circulation component and the gas outlet of the gas collector are connected. The gas outlet of the gas circulation component and the gas inlet of the gas collector are also connected. This application achieves rapid detection of formaldehyde content in POM particles with high accuracy through the gas circulation connection between the POM hot-melt assembly and the formaldehyde detection assembly.

[0051] The above description is only an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A device for detecting formaldehyde content in polyoxymethylene particles, characterized in that, The detection device includes a polyoxymethylene hot melt assembly (1) and a formaldehyde detection assembly (2). The polyoxymethylene hot melt assembly (1) includes a polyoxymethylene melting chamber (11) and a gas collector (12); the gas collector (12) is located below the polyoxymethylene melting chamber (11); and the polyoxymethylene melting chamber (11) and the gas collector (12) are spatially connected through a melt pipe (13); The formaldehyde detection component (2) includes a formaldehyde sensor (21) and a gas circulation component (22); the formaldehyde sensor (21) is disposed inside the gas circulation component (22); the gas inlet (221) of the gas circulation component and the gas outlet (121) of the gas collector are spatially connected; the gas outlet (222) of the gas circulation component and the gas inlet (122) of the gas collector are spatially connected.

2. The device for detecting formaldehyde content in polyoxymethylene particles according to claim 1, characterized in that, The height of the gas outlet (121) of the gas collector is less than the height of the gas inlet (122) of the gas collector.

3. The device for detecting formaldehyde content in polyoxymethylene particles according to claim 1, characterized in that, The melt pipe (13) is positioned at a first vertical angle between the polyoxymethylene melting chamber (11) and the gas collector (12).

4. The device for detecting formaldehyde content in polyoxymethylene particles according to claim 2, characterized in that, The polyoxymethylene hot melt assembly (1) also includes a load application element (14). The load application member (14) is disposed above the polyoxymethylene melting cavity (11) and is spatially connected to the polyoxymethylene melting cavity (11).

5. The device for detecting formaldehyde content in polyoxymethylene particles according to claim 1, characterized in that, The polyoxymethylene hot melt assembly (1) also includes a seal (15); The sealing element (15) is disposed between the polyoxymethylene melting chamber (11) and the gas collector (12).

6. The device for detecting formaldehyde content in polyoxymethylene particles according to claim 1, characterized in that, The detection device also includes a lifting platform (3), which is located below the gas collector (12).

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