Climate box method formaldehyde real-time monitoring system and method based on bypass cycle detection

Abstract

The invention provides a climate box method formaldehyde real-time monitoring system and method based on bypass cycle detection, and belongs to the technical field of detection. A climate box method formaldehyde real-time monitoring system based on bypass circulation detection comprises a climate box body and a bypass detection module connected to the climate box body, and the bypass detection module comprises a flow collection module, a constant temperature conveying module, a formaldehyde detection module and a backflow module which are connected in sequence. The flow acquisition module is connected with a sampling port of the climate box main body and is used for extracting detection gas from the climate box main body, and the flow control range is 50-200 mL / min; the constant-temperature conveying module is used for heating the conveyed gas, so that the temperature of the conveyed gas is kept consistent with that of the gas in the climate box main body; the formaldehyde detection module is used for detecting the formaldehyde concentration of the gas; and a backflow pipe of the backflow module extends into the climate box main body and is used for enabling the detected gas to flow back into the climate box main body.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of detection, in particular to a climate chamber method formaldehyde real-time monitoring system and method based on bypass circulation detection. BACKGROUND

[0002] The climate chamber method is an arbitration method for determining the formaldehyde release amount of artificial boards and their products. The method specified in the current national standard GB / T 17657-2022 requires periodic extraction of gas from the climate chamber and determination by chemical methods such as phenol reagent spectrophotometry. This method has the disadvantages of long cycle (usually several weeks), complicated operation, inability to obtain continuous release data, and possible slight disturbance of the environmental balance in the chamber during sampling.

[0003] To overcome the above-mentioned shortcomings, attempts have been made to directly embed formaldehyde electrochemical sensors or optical sensors in the climate chamber. However, this direct integration approach has inherent defects, such as temperature interference, the sensor itself may heat up or there is a temperature difference between its cavity and the chamber, causing local microenvironment changes, even condensation, affecting the strict constant temperature and humidity conditions in the chamber; gas consumption and pressure disturbance, some sensors need to continuously extract sample gas, causing significant changes in the total amount of gas and pressure in the chamber, disrupting the static balance; cross-contamination risk, the sensor may become an adsorption source or a source of pollution, affecting the background concentration in the chamber.

[0004] In recent years, although attempts have been made to directly embed sensors in the climate chamber (such as CN117607368A) to solve the sampling interference problem, this approach introduces new technical defects, such as the heat generated by the sensor itself during operation disrupting the thermal balance in the chamber; its physical presence disturbs the pre-set airflow field in the chamber; the sensor cavity may become an adsorption source or a source of pollution, affecting the background concentration. Therefore, the existing technology has not truly solved the contradiction between "real-time monitoring" and "environmental non-interference", but has instead created a new technical barrier. Therefore, there is an urgent need for a solution that can achieve real-time online monitoring while ensuring that the environment in the climate chamber is not disturbed. SUMMARY

[0005] The present application aims to overcome the above-mentioned problems in the existing technology and proposes a climate chamber method formaldehyde real-time monitoring system and method based on bypass circulation detection.

[0006] The purpose of the present application can be achieved by the following technical solutions: The bypass circulation detection-based climate chamber method formaldehyde real-time monitoring system comprises a climate chamber main body and a bypass detection module connected to the climate chamber main body, wherein the bypass detection module comprises a flow collection module, a constant-temperature conveying module, a formaldehyde detection module, a reflux module and a constant-temperature and constant-humidity module connected in sequence; the flow collection module is connected to a sampling port of the climate chamber main body and used for extracting a detection gas from the climate chamber main body, and the flow control range is 50-200 mL / min; the constant-temperature conveying module is used for heating the conveyed gas to keep the temperature of the conveyed gas consistent with that in the climate chamber main body; the formaldehyde detection module is used for detecting the formaldehyde concentration of the gas; the reflux pipe of the reflux module extends to the inside of the climate chamber main body and is used for refluxing the gas after detection into the climate chamber main body; and the constant-temperature and constant-humidity module is installed on the reflux pipe and used for keeping the temperature and humidity of the gas consistent with those of the gas in the climate chamber main body.

[0007] In the bypass circulation detection-based climate chamber method formaldehyde real-time monitoring system, the constant-temperature conveying module comprises a gas pipeline, a heat preservation layer arranged outside the gas pipeline and a heating element; the heating element is connected to a temperature controller and used for controlling the deviation of the temperature of the gas in the pipeline from the set temperature of the climate chamber main body to be less than or equal to ±0.5℃.

[0008] In the bypass circulation detection-based climate chamber method formaldehyde real-time monitoring system, the reflux pipe is filled with inert materials, and the specific surface area of the inert materials is greater than or equal to 200 m² / m³.

[0009] In the bypass circulation detection-based climate chamber method formaldehyde real-time monitoring system, the inert materials are stainless steel wire meshes or PTFE fillers.

[0010] In the bypass circulation detection-based climate chamber method formaldehyde real-time monitoring system, the flow collection module comprises a micro-pump, which operates in an intermittent mode, sleeps for a second predetermined time after operating for a first predetermined time.

[0011] In the bypass circulation detection-based climate chamber method formaldehyde real-time monitoring system, the sensor in the formaldehyde detection module is any one of the following sensors: an electrochemical formaldehyde sensor; a non-dispersive infrared (NDIR) sensor; a tunable diode laser absorption spectroscopy (TDLAS) sensor.

[0012] In the bypass circulation detection-based climate chamber method formaldehyde real-time monitoring system, the formaldehyde detection module comprises a low dead volume detection cavity and a sensor built therein, and the inner wall of the low dead volume detection cavity is polished or coated with a chemical inert material.

[0013] A climate chamber method formaldehyde real-time monitoring method of a system, characterized by comprising the following steps: S1, start the micro-flow collection module to extract the gas sample at a flow rate of ≤200 mL / min; S2, make the gas flow through the constant-temperature conveying module to keep the temperature consistent with that of the climate chamber body; S3, convey to the formaldehyde detection module for concentration measurement; S4, after the measurement, make the gas flow through the reflux pipe and keep the temperature and humidity of the gas consistent with those of the gas in the climate chamber body on the constant-temperature and constant-humidity module; S5, send the gas back to the climate chamber body through the reflux port.

[0014] In the climate chamber method formaldehyde real-time monitoring method, in step S1, the flow collection module operates in an intermittent mode, and the cycle operation is performed according to a first predetermined time of operation and a second predetermined time of hibernation.

[0015] In the climate chamber method formaldehyde real-time monitoring method, the temperature controller adopts a PID control algorithm to realize accurate control of a temperature deviation of ≤±0.5℃.

[0016] In the climate chamber method formaldehyde real-time monitoring method, after step S5, the system enters a hibernation state, and S1-S5 are re-executed after a predetermined time interval.

[0017] Compared with the prior art, the present application has the following advantages: In the present application, the to-be-measured gas in the climate chamber body enters the flow collection module of the bypass detection module through a pre-set sampling port, the flow collection module extracts the gas in a precise range of 50-200 mL / min, which not only ensures the required amount of gas for detection, but also avoids excessive extraction amount leading to pressure fluctuation in the chamber, the detected gas is extracted into the constant-temperature conveying module, the module is adjusted by active heating to keep the gas temperature in the conveying process completely consistent with the constant-temperature environment in the climate chamber body, eliminate local micro-environment changes caused by temperature difference, after constant-temperature processing, the gas flows into the formaldehyde detection module to detect the formaldehyde concentration in the gas in real time, generate continuous concentration data, after the detection, the gas directly flows back to the climate chamber body through the reflux pipe of the reflux module, realize the closed-loop circulation of the gas, not only avoid the change of the chamber pressure and the total amount of gas caused by the loss of the gas, but also eliminate the cross-contamination risk possibly caused by the direct embedding of the sensor. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of module connection in the present application. DETAILED DESCRIPTION

[0019] The technical solutions of the embodiments of the present invention 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 the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 As shown, a real-time formaldehyde monitoring system based on bypass circulation detection in a climate chamber includes a climate chamber body and a bypass detection module connected to the climate chamber body. The bypass detection module includes a flow acquisition module, a constant temperature delivery module, a formaldehyde detection module, a reflux module, and a constant temperature and humidity module connected in sequence. The flow acquisition module is connected to the sampling port of the climate chamber body and is used to extract the detection gas from the climate chamber body, with a flow rate control range of 50-200 mL / min. The constant temperature delivery module is used to heat the delivered gas to ensure that the temperature of the delivered gas is consistent with the temperature of the gas inside the climate chamber body. The formaldehyde detection module is used to detect the formaldehyde concentration in the gas. The reflux module's reflux pipe extends into the climate chamber body to return the detected gas to the climate chamber body. The constant temperature and humidity module is installed on the reflux pipe to ensure that the gas temperature and humidity are consistent with the temperature and humidity of the gas inside the climate chamber body. In other words, the humidity and temperature of the gas flowing out for detection are controlled before it returns to the climate chamber, ensuring that the temperature and humidity of the gas are consistent when it returns to the climate chamber.

[0021] In this application, the gas to be tested inside the climate chamber enters the flow acquisition module of the bypass detection module through a preset sampling port. The flow acquisition module extracts gas within a precise range of 50-200 mL / min, ensuring the required gas volume for detection while avoiding excessive extraction that could cause pressure fluctuations within the chamber. The extracted gas then enters the constant-temperature delivery module, which actively heats and regulates the gas temperature during delivery to maintain complete consistency with the constant-temperature environment inside the climate chamber, eliminating local microenvironmental changes caused by temperature differences. After temperature control, the gas flows into the formaldehyde detection module, where the formaldehyde concentration is detected in real time, generating continuous concentration data. After detection, the gas flows back directly to the climate chamber through the return pipe of the return module, achieving a closed-loop gas circulation. This avoids changes in pressure and total gas volume within the chamber due to gas loss and eliminates the risk of cross-contamination that could arise from directly integrating the sensor.

[0022] The bypass detection module can continuously extract gas for detection throughout the process, eliminating the need for periodic sampling as required by traditional chemical methods. It can capture the dynamic changes in formaldehyde release in real time and generate continuous concentration curves, solving the pain points of long cycles and discrete data in traditional methods.

[0023] The constant-temperature conveying module eliminates the micro-environmental interference caused by gas temperature difference, avoids the influence of dewing or temperature fluctuation on the detection results, and ensures that all the extracted gas is returned without gas consumption and pressure fluctuation, thereby maintaining the static balance in the climate chamber.

[0024] The sensor is not directly built-in the climate chamber main body, and the cavity thereof is isolated from the climate chamber, thereby avoiding problems such as sensor heating, physical disturbance, adsorption and pollution from the root.

[0025] The flow acquisition module adopts a precise micro-piston pump driven by a stepping motor, and the flow is stably controlled at 50-200 mL / min, and 60 ml / min is selected in the application. The preferred range is between 50 mL / min and 200 mL / min. If the flow is too large, the "non-interference" significance is lost, and if it is too small, the system response may be delayed.

[0026] The connection position of the return pipe and the climate chamber main body is that the gas outlet of the return pipe is in a strong gas flow representative area, and the gas injection direction of the gas outlet of the return pipe is consistent with the main gas flow direction, thereby minimizing the disturbance to the overall flow field in the chamber.

[0027] Specifically, the constant-temperature conveying module comprises a gas path pipeline, a heat preservation layer arranged outside the gas path pipeline, and a heating element; the heating element is connected with a temperature controller, and is used for controlling the deviation of the gas temperature in the pipeline from the set temperature of the climate chamber main body to be ≤±0.5℃.

[0028] The heat preservation layer outside the gas path pipeline can effectively isolate the influence of the external environment temperature, avoid the temperature drop of the gas in the pipeline due to heat loss during the conveying process, ensure that the gas temperature in the pipeline is not disturbed, and solve the potential problem of secondary temperature change during the conveying process.

[0029] The gas path pipeline is wrapped with a 10mm-thick polyethylene foam heat preservation layer, and a flexible silica gel heating belt is wound thereon as the heating element. The heating belt is controlled by a temperature controller such as Omron E5CS series, and the set temperature is 23.0℃.

[0030] In another scheme, the constant-temperature conveying module adopts a double-sleeve structure. The inner pipe is a φ6mm stainless steel pipe for transmitting gas, and the outer pipe is a φ16mm PVC pipe. The heat preservation material is filled between the two pipes, and the constant-temperature water controlled by the climate chamber constant-temperature water system is circulated to realize more accurate isothermal control, and the temperature fluctuation is less than ±0.2℃.

[0031] Specifically, the return pipe is filled with inert material, and the specific surface area of the inert material is ≥200 m² / m³.

[0032] Specifically, the inert material is stainless steel wire mesh or PTFE filler.

[0033] Its surface is smooth and chemically stable, neither reacting with formaldehyde nor releasing metal ions or volatile substances, forming a gradient air flow resistance structure, when the backflow gas flows through, it needs to pass through the mesh pores layer by layer, and the flow rate is gradually reduced, compared with ordinary porous materials, its air flow resistance is more uniform, and the gas outlet flow rate can be accurately controlled at the air flow disturbance threshold in the climate chamber.

[0034] Specifically, the flow collection module includes a micro air pump, which operates in an intermittent mode, and sleeps for a second predetermined time after running for a first predetermined time.

[0035] The system works in an intermittent mode, starts to run for 8 minutes every 20 minutes, and sleeps after completing measurement and backflow.

[0036] Specifically, the sensor in the formaldehyde detection module is any one of the following sensors: electrochemical formaldehyde sensor; non-dispersive infrared (NDIR) sensor; laser absorption spectroscopy (TDLAS) sensor.

[0037] Preferably, a high selectivity electrochemical formaldehyde sensor from the UK DART company is selected, which has a measurement range of 0-10 ppm and a resolution of up to 1 ppb. The sensor is installed in a stainless steel detection cavity with a polished inner wall and a volume of about 3 mL.

[0038] The laser absorption spectroscopy (TDLAS) sensor is a tunable diode laser absorption spectroscopy (TDLAS) gas analyzer, such as the German NEO Monitors laser analyzer.

[0039] Specifically, the formaldehyde detection module includes a low dead volume detection cavity and a sensor built-in, and the inner wall of the low dead volume detection cavity is polished or coated with a chemically inert material.

[0040] The low dead volume detection cavity is a cylindrical stainless steel cavity (φ50mm×50mm), which is tightly filled with stainless steel 316 wire mesh. The backflow pipe is a PTFE pipe, and its outlet direction is optimized by CFD simulation and consistent with the main circulating air flow direction in the chamber.

[0041] The application can monitor the dynamic change of formaldehyde concentration in the climate chamber in real time, draw a complete release curve, and the measurement error is less than 5% compared with the standard method of GB / T 17657-2022 at the equilibrium point. And through actual measurement, during the continuous operation of the system, the temperature fluctuation in the climate chamber is not more than ±0.1℃, and the humidity fluctuation is not more than ±1%RH, which is significantly better than the control accuracy requirement of ±0.5℃ and ±3%RH specified in the national standard, proving that the influence on the main chamber environment is negligible.

[0042] A system climate chamber method for real-time monitoring of formaldehyde, characterized in that it comprises the steps of: S1, starting the micro-flow collection module to extract the gas sample at a flow rate of ≤200 mL / min; S2, making the gas flow through the constant-temperature conveying module to keep the temperature consistent with the main body of the climate chamber; S3, conveying to the formaldehyde detection module for concentration measurement; S4, after measurement, the gas flows through the reflux pipe and is kept on the constant-temperature and constant-humidity module, so that the temperature and humidity of the gas are consistent with those in the main body of the climate chamber. S5, the gas is sent back to the main body of the climate chamber through the reflux port.

[0043] Specifically, in step S1, the flow collection module operates in intermittent mode, and the operation is cycled according to a first predetermined time and a second predetermined time of hibernation.

[0044] Specifically, the temperature controller adopts a PID control algorithm to achieve accurate control of the temperature deviation ≤±0.5℃.

[0045] Specifically, after step S5, the system enters a hibernation state, and after a predetermined time interval, S1-S5 are executed again.

[0046] The system can work in continuous mode or intermittent mode. The intermittent mode is more preferred, for example, it is started to run for 5 minutes every 15 minutes, and after completing a measurement, it enters a hibernation state. This can further reduce any potential long-term cumulative effect and maximize the realization of non-interference.

[0047] The system works almost continuously, but performs a 10-minute zero-point calibration cycle every 24 hours, i.e., it inhales zero air and passes through activated carbon filtration to calibrate the sensor baseline, ensuring the long-term accuracy of the data.

[0048] It should be noted that all directional indications in the embodiments of the application, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationship between the components, the movement condition, etc. between the components in a certain specific posture, as shown in the drawings, and if the specific posture changes, the directional indications will also change accordingly.

[0049] In addition, the descriptions of "first", "second", etc. in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. Meanwhile, the meaning of "and / or" appearing throughout the text is that it includes three schemes, for example, "A and / or B" includes A scheme, or B scheme, or A and B schemes are satisfied at the same time. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection required by the present application.

[0050] The above components are all general standard components or components known to those skilled in the art, and their structure and principle can be known by those skilled in the art through technical manual or through conventional experimental methods.

[0051] It should be noted that the device embodiments described above are only schematic, and the units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e. they can be located in one place or distributed on multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the present embodiment. In addition, the connection relationship between the modules in the device embodiment provided by the present application indicates that there is a communication connection between them, which can be realized as one or more communication buses or signal lines. Those skilled in the art can understand and implement it without creative labor.

[0052] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only for the specific embodiments of the present application and does not limit the protection scope of the present application. It is particularly pointed out that any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A real-time formaldehyde monitoring system based on a climate chamber method using bypass loop detection, characterized in that, The system includes a climate chamber body and a bypass detection module connected to the climate chamber body. The bypass detection module includes a flow acquisition module, a constant temperature delivery module, a formaldehyde detection module, a reflux module, and a constant temperature and humidity module connected in sequence. The flow acquisition module is connected to the sampling port of the climate chamber body and is used to extract the detection gas from the climate chamber body, with a flow rate control range of 50-200 mL / min. The constant temperature delivery module is used to heat the delivered gas to ensure that the temperature of the delivered gas is consistent with the temperature of the gas inside the climate chamber body. The formaldehyde detection module is used to detect the formaldehyde concentration of the gas. The reflux module has a reflux pipe extending into the climate chamber body to return the gas after detection to the climate chamber body. The constant temperature and humidity module is installed on the reflux pipe to ensure that the temperature and humidity of the gas are consistent with the temperature and humidity of the gas inside the climate chamber body.

2. The formaldehyde real-time monitoring system based on bypass loop detection in a climate chamber according to claim 1, characterized in that, The constant temperature delivery module includes a gas pipeline, an insulation layer installed outside the gas pipeline, and a heating element; the heating element is connected to a temperature controller to control the deviation between the gas temperature inside the pipeline and the set temperature of the climate chamber body to ≤ ±0.5℃.

3. The formaldehyde real-time monitoring system based on bypass loop detection in a climate chamber according to claim 1, characterized in that, The reflux pipe is filled with an inert material, the inert material having a specific surface area ≥200 m² / m³.

4. The formaldehyde real-time monitoring system based on bypass loop detection in a climate chamber according to claim 3, characterized in that, The inert material is stainless steel wire mesh or PTFE filler.

5. The formaldehyde real-time monitoring system based on bypass loop detection in a climate chamber according to claim 1, characterized in that, The flow acquisition module includes a miniature air pump that operates in intermittent mode, running for a first predetermined time and then going into a dormant state for a second predetermined time.

6. The formaldehyde real-time monitoring system based on bypass loop detection in a climate chamber according to claim 1, characterized in that, The sensor in the formaldehyde detection module is any one of the following: Electrochemical formaldehyde sensor; Non-dispersive infrared (NDIR) sensor; Laser absorption spectroscopy (TDLAS) sensor.

7. The formaldehyde real-time monitoring system based on bypass loop detection in a climate chamber according to claim 1, characterized in that, The formaldehyde detection module includes a low dead volume detection chamber and a built-in sensor. The inner wall of the low dead volume detection chamber is polished or coated with a chemically inert material.

8. A real-time monitoring method for a formaldehyde real-time monitoring system using a climate chamber method according to any one of claims 1-7, characterized in that, Including the following steps: S1. Start the micro-flow acquisition module to extract gas samples at a flow rate of ≤200 mL / min; S2. Allow the gas to flow through the constant temperature conveying module to maintain the temperature consistent with the main body of the climate chamber; S3. The sample is then transported to the formaldehyde detection module for concentration measurement. S4. After measurement, the gas flows through the return pipe and is kept in constant temperature and humidity module so that the gas temperature and humidity are consistent with the gas temperature and humidity inside the climate chamber. S5. The gas is returned to the main body of the climate chamber through the return port.

9. The real-time monitoring method of the formaldehyde real-time monitoring system using the climate chamber method according to claim 8, characterized in that, In step S1, the traffic acquisition module operates in intermittent mode, cycling through a first predetermined running time and a second predetermined sleep time.

10. The real-time monitoring method of the formaldehyde real-time monitoring system using the climate chamber method according to claim 8, characterized in that, After step S5, the system enters a sleep state and re-executes S1-S5 after a predetermined interval.

Images