A multi-range bypass dilution, absorption saturation protection and valid reading lockout assembly and control method for infrared gas detection equipment

Abstract

The present application relates to the technical field of infrared gas detection, and discloses a multi-range bypass dilution, absorption saturation protection and effective reading locking assembly and control method for an infrared gas detection device. The assembly comprises a range switching valve group, a main detection gas path, a bypass dilution gas path, a proportional flow limiting unit, a mixing buffer cavity, a detection gas chamber, an infrared optical detection unit, a saturation determination unit, a range control unit and an effective reading locking unit, etc. The saturation determination unit determines saturation risk according to absorption intensity, transmitted light intensity, pressure / flow state and dilution ratio. When saturation risk is entered, the range control unit switches the bypass dilution range, reacquires after mixing is stable, locks the effective reading and converts the detection result when the stable condition is met, prohibits this output and prompts retesting when the reading is unstable, and prohibits output and prompts maintenance when the protection threshold is exceeded. Thus, the reliability of high-concentration sample gas detection is improved.

Description

Technical Field

[0001] This invention relates to the field of infrared gas detection technology, and in particular to a multi-range bypass dilution, absorption saturation protection and effective reading locking component and control method for infrared gas detection equipment. It is applicable to the control of high-concentration sample gas range switching, absorption saturation interception, dilution re-acquisition and effective result output during the infrared detection process of exhaled gas, ambient gas or other gases to be tested. Background Technology

[0002] Infrared gas detection equipment typically utilizes the absorption characteristics of the gas being measured in a specific infrared band to obtain the concentration of the target gas. When the concentration of the target gas is low or within the linear operating region, a good correlation can be maintained between the infrared absorption intensity and the concentration. However, when the concentration of the sample gas is too high, the transmitted light intensity in the detection chamber may approach the lower limit, and the absorption response may enter the nonlinear or saturation region, leading to an increase in concentration inversion error.

[0003] Existing infrared gas detection equipment often employs a fixed optical path, fixed sampling flow rate, and single-range detection method. When high-concentration sample gas enters the detection chamber, single-range detection can easily lead to issues such as the signal approaching full scale, analog-to-digital conversion saturation, excessively low transmitted light intensity, or unstable repeated readings. If the equipment still directly outputs the detection result, it may cause misjudgment; if it only simply indicates that the range is exceeded, it cannot provide a usable detection result after dilution.

[0004] Some devices handle high-concentration sample gases through external dilution or manual range switching. However, external dilution can easily introduce proportional errors, response lags, and operational inconsistencies. If the dilution gas path, main detection gas path, pressure / flow status, and result output criteria are not interlocked, the device cannot confirm whether the dilution ratio is effective, nor can it determine whether the post-dilution readings have stabilized.

[0005] Therefore, there is a need for a component and control method that can automatically switch the bypass dilution range when infrared absorption enters the risk of saturation, and lock the valid reading after the mixing is stable and the reading consistency is met, so that the infrared gas detection device can still achieve reliable measurement under high concentration sample gas conditions, and prohibit abnormal result output when the protection threshold is exceeded. Summary of the Invention

[0006] The technical problem to be solved by this invention is that when infrared gas detection equipment is used in the case of high concentration sample gas or sudden increase in concentration, the infrared absorption signal of the detection chamber is prone to nonlinearity or saturation. Existing single-range detection methods are difficult to take into account high concentration protection, automatic dilution, dilution ratio confirmation and effective reading output.

[0007] To address the aforementioned technical problems, this invention provides a multi-range bypass dilution, absorption saturation protection, and effective reading locking assembly for an infrared gas detection device. This assembly includes a sample gas inlet, a range switching valve group, a main detection gas path, a bypass dilution gas path, a dilution gas inlet, a proportional flow limiting unit, a mixing buffer chamber, a detection gas chamber, an infrared optical detection unit, an absorption intensity calculation unit, a saturation determination unit, a range control unit, an effective reading locking unit, a result output unit, an exhaust unit, a pressure / flow detection unit, a storage unit, and a maintenance reminder unit.

[0008] The range switching valve assembly switches the sample gas between the main detection gas path and the bypass dilution gas path. The bypass dilution gas path, through a proportional flow limiting unit, introduces the sample gas and dilution gas into the mixing buffer chamber according to a preset dilution ratio. The mixed sample gas then enters the detection gas chamber. The infrared optical detection unit obtains the infrared absorption signal of the sample gas in the detection gas chamber, the absorption intensity calculation unit calculates the absorption intensity and transmitted light intensity, and the saturation determination unit determines whether the sample gas is at risk of absorption saturation based on the absorption intensity, transmitted light intensity, pressure / flow rate, and dilution ratio.

[0009] When the absorption saturation risk has not been reached and the reading is stable, the valid reading lock unit locks the valid reading of the current range. When the absorption saturation risk is reached, the range control unit switches to the bypass dilution gas path and performs high-range detection according to the preset dilution ratio. When the mixing is stable, the dilution ratio and the reading consistency meet the conditions, the valid reading lock unit locks the diluted valid reading and converts the detection result according to the dilution ratio. When the reading still does not meet the stability conditions, the result output unit prohibits the output of the current detection result and prompts for retesting. When the protection threshold is exceeded, the result output unit prohibits the output of the detection result and outputs a maintenance prompt through the maintenance prompt unit.

[0010] This invention also provides an infrared gas detection and control method, including starting detection and reading range parameters, opening the main detection gas path and acquiring signals, calculating absorption intensity and transmitted light intensity, and determining whether the absorption saturation risk has been reached; if the absorption saturation risk has not been reached and the reading is stable, locking the current range reading; if the absorption saturation risk has been reached, switching the bypass dilution range, waiting for the mixture to stabilize, and re-acquiring; if the diluted reading meets the stability condition, locking the valid reading and outputting the conversion result; if the reading does not meet the stability condition, prohibiting the output of the current result and prompting for retesting; if the protection threshold is exceeded, prohibiting the output of the result and prompting for maintenance.

[0011] Compared with the prior art, the present invention has the following advantages: First, it achieves automatic range expansion of high-concentration sample gas through bypass dilution gas path and range switching valve group; Second, it reduces the risk of erroneous output results under saturation state by jointly judging absorption intensity, transmitted light intensity and pressure / flow status; Third, it enables the diluted results to have a traceable and effective reading locking process by judging the mixing buffer chamber and stability conditions; Fourth, it forms a closed loop of high concentration protection, re-acquisition and result output access by recording invalid reasons, retest prompts and maintenance prompts. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the system structure of the multi-range bypass dilution, absorption saturation protection and effective reading locking components in an embodiment of the present invention.

[0013] Figure 2 This is a schematic diagram of the multi-range bypass dilution valve assembly and the mixing detection gas path structure in an embodiment of the present invention.

[0014] Figure 3 This is a schematic diagram illustrating the relationship between absorption saturation protection and multi-range switching in an embodiment of the present invention.

[0015] Figure 4 This is a flowchart of the absorption saturation protection and effective reading lockout control in an embodiment of the present invention. Detailed Implementation

[0016] The present invention will be described below with reference to the accompanying drawings and embodiments. The described embodiments are used to explain the technical solutions of the present invention and do not limit the scope of protection of the present invention.

[0017] Example 1: As Figure 1 As shown, the multi-range bypass dilution, absorption saturation protection, and effective reading locking assembly includes a sample gas inlet 101, a range switching valve group 102, a main detection gas path 103, a bypass dilution gas path 104, a dilution gas inlet 105, a proportional flow limiting unit 106, a mixing buffer chamber 107, a detection gas chamber 108, an infrared optical detection unit 109, an absorption intensity calculation unit 110, a saturation determination unit 111, a range control unit 112, an effective reading locking unit 113, a result output unit 114, an exhaust unit 115, a pressure / flow detection unit 116, a storage unit 117, and a maintenance reminder unit 118.

[0018] The sample gas inlet 101 receives the sample gas to be tested. The range switching valve assembly 102 selects either the main detection gas path 103 or the bypass dilution gas path 104 according to the control command of the range control unit 112. The main detection gas path 103 is suitable for detection states with low concentrations or no risk of saturation, while the bypass dilution gas path 104 is suitable for detection states where the absorption intensity enters the risk of saturation or requires an extended range. The dilution gas inlet 105 provides dilution gas to the proportional flow limiting unit 106, which introduces the dilution gas and sample gas into the mixing buffer chamber 107 according to a preset dilution ratio.

[0019] The sample gas output from the mixing buffer chamber 107 enters the detection chamber 108, and the infrared optical detection unit 109 obtains the infrared absorption signal of the sample gas in the detection chamber 108. The absorption intensity calculation unit 110 calculates the absorption intensity and transmitted light intensity based on the infrared absorption signal, and the saturation determination unit 111 determines whether there is a risk of absorption saturation based on the absorption intensity, transmitted light intensity, pressure / flow rate, and dilution ratio. The range control unit 112 performs range switching, re-acquisition, or output prohibition control based on the determination result. The valid reading locking unit 113 locks the valid reading when the reading is stable, and the result output unit 114 outputs the result. The relevant range status, dilution ratio, and invalidation reason are recorded by the storage unit 117, and the maintenance prompt unit 118 outputs a retest or maintenance prompt.

[0020] Example 2: Figure 2 As shown, the multi-range bypass dilution valve assembly and mixed detection gas path structure includes a sample gas inlet 201, a main gas path 202, a bypass inlet 203, a dilution gas inlet 204, a dilution gas flow restrictor 205, a dilution valve 206, a bypass proportional channel 207, a mixing chamber 208, a flow equalization structure 209, a detection gas chamber 210, an exhaust port 211, a low-range channel 212, a high-range channel 213, a valve assembly housing 214, and a pressure detection port 215.

[0021] The sample gas inlet 201 connects to the main gas path 202, forming a low-range channel 212; the bypass inlet 203 connects to the high-range channel 213 and merges with the dilution gas via the bypass proportional channel 207. The dilution gas inlet 204 supplies dilution gas to the bypass proportional channel 207 via the dilution gas flow restrictor 205 and the dilution valve 206. The bypass proportional channel 207 merges with the sample gas to be tested in the mixing chamber 208. The flow equalization structure 209 is used to reduce the concentration gradient after mixing, making the diluted sample gas entering the detection chamber 210 more stable. The detected gas is discharged through the exhaust port 211.

[0022] The valve assembly housing 214 is used to fix the relative positions between the main gas path 202, the bypass proportional channel 207, the mixing chamber 208, and the detection chamber 210. The pressure detection port 215 can be located before or after the mixing chamber 208, at the inlet of the detection chamber 210, or at the bypass proportional channel 207, for detecting pressure, differential pressure, or flow rate changes. The range control unit determines the actual dilution ratio based on the dilution gas flow restrictor 205, the dilution valve 206, the pressure detection port 215, and the valve position status, and prohibits the output of detection results when the actual dilution ratio exceeds the allowable error.

[0023] Example 3: Figure 3 As shown, the relationship between absorption saturation protection and multi-range switching includes the gas concentration axis 301, absorption response axis 302, main gas path absorption response curve 303, diluted absorption response curve 304, linear working area 305, calibrable area 306, saturation protection area 307, range switching threshold 308, and saturation judgment upper limit 309.

[0024] Within the low concentration range, the main gas path absorption response curve 303 is in the linear operating region 305, and the current range reading can be directly output. As the concentration increases, the main gas path absorption response curve 303 enters the calibrable region 306, and the range control unit can perform calibration based on the calibration parameters. When the absorption response approaches the upper limit of saturation judgment 309 or exceeds the range switching threshold 308, the saturation judgment unit determines that it has entered the saturation protection zone 307, and the range control unit switches to the bypass dilution gas path, so that the diluted absorption response curve 304 returns to the usable detection range.

[0025] Example 4: Figure 4 As shown, the absorption saturation protection and valid reading lock control process includes: starting detection and reading range parameters 401, opening the main detection gas path and acquiring signals 402, calculating absorption intensity and transmitted light intensity 403, and determining whether saturation risk has been entered 404. If saturation risk has not been entered, the current range candidate reading is locked 405, and it is determined whether the reading meets the stability condition 406; if the stability condition is met, the valid reading is locked 407, and the detection result is output and stored 408.

[0026] When the saturation risk is detected (404), the range control unit switches the bypass dilution range (409), waits for the mixture to stabilize (410), and reacquires the diluted signal (411). After reacquisition, it returns to calculate the absorption intensity and transmitted light intensity (403) and continues to perform the saturation risk assessment (404). If the reading does not meet the stability condition (406), it disables the output of the current result and prompts for retesting (412); if the high-range dilution still exceeds the protection threshold, it disables the output of the result and prompts for maintenance (412).

[0027] In a specific application, infrared gas detection equipment can be used to detect carbon dioxide, methane, carbon monoxide, volatile organic compounds, or other gases with infrared absorption characteristics. The infrared bands corresponding to different target gases, the optical path length of the detection chamber, the main gas flow rate, the dilution ratio, the range switching threshold, the upper limit of saturation judgment, and the stability conditions can be set according to the equipment structure and detection accuracy requirements. The core of this invention lies in combining multi-range bypass dilution, absorption saturation protection, and effective reading locking to form a result output access mechanism under high-concentration sample gas conditions.

Claims

1. A multi-range bypass dilution, absorption saturation protection, and effective reading locking assembly for an infrared gas detection device, comprising a sample gas inlet, a range switching valve group, a main detection gas path, a bypass dilution gas path, a dilution gas inlet, a proportional flow limiting unit, a mixing buffer chamber, a detection gas chamber, an infrared optical detection unit, an absorption intensity calculation unit, a saturation determination unit, a range control unit, an effective reading locking unit, a result output unit, an exhaust unit, a pressure / flow detection unit, a storage unit, and a maintenance prompt unit, characterized in that, The range switching valve assembly is used to switch the sample gas to be tested between the main detection gas path and the bypass dilution gas path; The proportional flow limiting unit is used to introduce the dilution gas and the sample gas to be tested into the mixing buffer chamber according to the preset dilution ratio; the detection gas chamber receives the sample gas to be tested in the main detection gas path or the sample gas to be tested after being diluted by the bypass dilution gas path; the infrared optical detection unit is used to obtain the infrared absorption signal corresponding to the sample gas in the detection gas chamber; the absorption intensity calculation unit calculates the absorption intensity or transmitted light intensity based on the infrared absorption signal; the saturation determination unit determines whether the absorption saturation risk has been entered based on at least one of the absorption intensity, transmitted light intensity, pressure / flow status and dilution ratio; the range control unit switches to the bypass dilution gas path and controls the dilution ratio when the absorption saturation risk is entered; when the stability condition is met, the effective reading locking unit locks the effective reading; when the reading does not meet the stability condition, the current result output is prohibited and a retest is prompted; when the protection threshold is exceeded, the result output is prohibited and a maintenance prompt is output through the maintenance prompt unit.

2. The component according to claim 1, characterized in that, The bypass dilution gas path includes at least two selectable dilution ratio channels. Each dilution ratio channel is equipped with at least one of a fixed flow restrictor, a micro-orifice flow restrictor, a proportional valve, or a mass flow control device to form dilution ratios corresponding to different ranges.

3. The component according to claim 1, characterized in that, The range switching valve group includes a direct-access low-range state, a bypass high-range state, and a re-acquisition control state, and is equipped with a one-way valve or an interlock valve position to prevent dilution gas from entering the sample gas inlet in reverse or unmixed sample gas from entering the detection gas chamber directly.

4. The component according to claim 1, characterized in that, The saturation determination unit determines that it is at risk of absorption saturation when at least one of the following conditions occurs: transmitted light intensity is below the lower limit, absorption intensity is above the upper limit of linearity, analog-to-digital conversion value reaches the upper limit, readings for multiple consecutive modulation cycles are close to full scale, or pressure / flow rate is abnormal in the main detection gas path, bypass dilution gas path, dilution gas inlet, or proportional flow limiting unit.

5. The component according to claim 1, characterized in that, The pressure / flow detection unit is used to detect the pressure, differential pressure, or flow rate of the main detection gas path, bypass dilution gas path, or dilution gas inlet, and the range control unit determines the actual dilution ratio based on the pressure, differential pressure, flow rate, flow limiting device parameters, and valve position status.

6. The component according to claim 1, characterized in that, The effective reading locking unit waits for the mixing stabilization time after switching the bypass dilution gas path, continuously collects the diluted infrared absorption signal for multiple modulation cycles, and locks the effective reading when the dilution ratio, absorption intensity fluctuation, pressure / flow fluctuation and baseline drift all meet the stabilization conditions.

7. The component according to claim 1, characterized in that, The range control unit calculates the target gas concentration based on at least one of the effective reading, dilution ratio, range calibration coefficient, and zero baseline, and writes the range status, dilution ratio, lockout time window, and saturation protection status into the result.

8. The component according to claim 1, characterized in that, The storage unit stores at least one of the following: range threshold, dilution ratio, pressure / flow threshold, absorption saturation threshold, linear operating range parameters, calibrable range parameters, saturation protection range parameters, maintenance frequency, and invalidation reason records.

9. An infrared gas detection and control method employing the component described in any one of claims 1 to 8, characterized in that, include: Start the detection and read the range parameters; turn on the main detection gas path and collect the infrared absorption signal; Calculate the absorption intensity and the transmitted light intensity; Determine if there is a risk of reaching absorption saturation; When there is no risk of absorption saturation and the reading meets the stability condition, the valid reading of the current range is locked; when the risk of absorption saturation is reached, the bypass dilution gas path is switched to, and the sample gas and dilution gas are mixed according to the preset dilution ratio; after the mixture stabilizes, the diluted infrared absorption signal is reacquired; it is determined whether the diluted reading meets the stability condition; if the stability condition is met, the valid reading is locked and the test result is converted according to the dilution ratio; if the stability condition is not met, the output of this result is prohibited and a retest is prompted. If the protection threshold is exceeded, the output of the detection results will be prohibited and a maintenance prompt will be displayed.

10. The method according to claim 9, characterized in that, Before locking a valid reading, the absorption intensity, transmitted light intensity, pressure / flow status, and dilution ratio of multiple consecutive modulation cycles are judged for consistency. When the consistency judgment is qualified, the test result is output and stored. When the consistency judgment is unqualified but does not exceed the protection threshold, the output of this result is prohibited and a retest is prompted. When the protection threshold is exceeded, the output of the test result is prohibited, the invalid reason is recorded, and a maintenance prompt is output.

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