High-temperature gas flow control system for gas analyzer

Abstract

The utility model provides a high-temperature gas flow control system for a gas analyzer, and relates to the technical field of engine tail gas detection, the high-temperature gas flow control system comprises a core sensor, the input end of the core sensor is connected with a sample gas inlet and a standard gas inlet, and the output end of the core sensor is connected with an exhaust port; the sampling pump is arranged between the core sensor and the exhaust port; the flow control module is arranged at the input end of the sampling pump and can control the gas flowing in from the sample gas inlet and / or the standard gas inlet to flow into the sampling pump when the sampling pump is started, so as to control the flow of the gas flowing through the core sensor; and the main control system is respectively connected with the core sensor and the flow control module. According to the gas analyzer, the problem that measurement is interfered due to different differential pressures on the two sides of the core sensor caused by different gas flows in a calibration state and a sampling state is solved, and the analysis accuracy of the gas analyzer is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of engine exhaust detection, and in particular to a high-temperature gas flow control system for a gas analyzer. Background Art

[0002] At present, gas analyzers are mostly used to analyze and measure the gas components in engine exhaust. However, due to factors such as the activity of gas components in exhaust gas, the entire system must be kept in a high temperature constant temperature state (above 190°C) to avoid condensation, adsorption and other factors that may reduce measurement accuracy.

[0003] However, in the prior art, there are gas analyzers that use a mid-mounted sampling pump or a post-mounted sampling pump. Among them, the mid-mounted sampling pump refers to a sampling pump located between the sampling pipeline and the core sensor in the gas circuit of the gas analyzer equipment, that is, when sampling, the sampling tube part is in a negative pressure state, and the pressure between the sampling pump and the measuring sensor and the exhaust port is positive; while the post-mounted sampling pump refers to a sampling pump arranged at the end of the entire gas circuit in the gas circuit of the gas analyzer equipment, located at the rear end of the sampling pipeline and the core measuring sensor and before the exhaust port of the equipment. In this way, the entire system before the sampling pump is in a negative pressure state, and the gas analyzer may have a sampling state and a calibration state. In the calibration state and the sampling state, different gas flow rates are required, so the differential pressure on both sides of the core sensor is different. If the flow pressure on both sides of the core sensor is unstable, it may interfere with the measurement, so there is a problem of unstable measurement accuracy, which affects the accuracy of the gas analyzer. Summary of the invention

[0004] The present application provides a high-temperature gas flow control system for a gas analyzer to at least solve the technical problems existing in the related art.

[0005] According to one aspect of an embodiment of the present application, a high-temperature gas flow control system for a gas analyzer is provided, including a core sensor, wherein the input end of the core sensor is connected to a sample gas inlet and a standard gas inlet, and the output end of the core sensor is connected to an exhaust port; further comprising: a sampling pump: arranged between the core sensor and the exhaust port; a flow control module: arranged at the input end of the sampling pump, capable of controlling the gas flowing in through the sample gas inlet and / or the standard gas inlet to flow into the sampling pump when the sampling pump is turned on, so as to control the gas flow flowing through the core sensor; a main control system: respectively connected to the core sensor and the flow control module.

[0006] As an optional implementation, a differential pressure sensor is further included, wherein two ends of the differential pressure sensor are respectively connected to two ends of the core sensor and to the main control system, so as to obtain the gas pressure difference at two ends of the core sensor.

[0007] As an optional embodiment, the flow control module includes: a pulse proportional valve and an air filter element. The air filter element is connected to the input end of the sampling pump through the pulse proportional valve. The pulse proportional valve is also connected to the main control system for controlling the amount of clean gas entering the sampling pump through the flow control module.

[0008] As an optional implementation, the main control system is configured to control the opening of the pulse proportional valve according to the measurement value of the differential pressure sensor.

[0009] As an optional implementation, it also includes an absolute pressure sensor, whose two ends are respectively connected to the output ends of the main control system and the core sensor, and can obtain the pressure at the output end of the core sensor to monitor the gas path.

[0010] As an optional implementation, the main control system is configured to output an alarm signal when the measurement value of the absolute pressure sensor is lower than the atmospheric pressure or higher than a preset maximum value.

[0011] As an optional embodiment, the high-temperature gas flow control system for the gas analyzer includes a sampling state and a calibration state. In the sampling state, the sample gas inlet is opened and the standard gas inlet is closed; in the calibration state, the standard gas inlet is opened and the sample gas inlet is closed.

[0012] As an optional implementation, it also includes a flow meter, which is arranged at the exhaust port and connected to the main control system.

[0013] As an optional implementation, the main control system is configured to perform multi-point data fitting according to the flow meter measurement value and the differential pressure sensor measurement value to obtain a fitting formula between the differential pressure sensor measurement value and the flow meter measurement value.

[0014] As an optional implementation, the flow control module includes a high temperature resistant pulse solenoid valve, which is arranged between the core sensor and the input end of the sampling pump and is used to control the gas flow of the sampling pump gas circuit.

[0015] In an embodiment of the present application, a high temperature gas flow control system for a gas analyzer is provided, comprising a core sensor, the input end of the core sensor is connected to a sample gas inlet and a standard gas inlet, and the output end of the core sensor is connected to an exhaust port; further comprising: a sampling pump: arranged between the core sensor and the exhaust port; a flow control module: arranged at the input end of the sampling pump, capable of controlling the gas flowing in through the sample gas inlet and / or the standard gas inlet to flow into the sampling pump when the sampling pump is turned on, so as to control the gas flow flowing through the core sensor; a main control system: connected to the core sensor and the flow control module respectively. The flow control module is arranged at the input end of the sampling pump, capable of controlling the air to flow into the sampling pump when the sampling pump is turned on, so that when the sampling pump is turned on, the air can be sucked in by the flow control module, so that the sample gas or the standard gas flows into the core sensor at a relatively stable flow rate, so that the pressure difference at both ends of the core sensor is kept as stable as possible, solving the problem that the gas flow rate is different in the calibration state and the sampling state, thereby causing the differential pressure on both sides of the core sensor to be different, thereby interfering with the measurement, and greatly improving the analysis accuracy of the gas analyzer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0018] Figure 1 It is a schematic diagram of an optional high-temperature gas flow control system for a gas analyzer provided according to an embodiment of the present application.

[0019] Reference numerals

[0020] 1 Main control system; 2 Core sensor, 21 Differential pressure sensor; 3 Sample gas inlet; 4 Standard gas inlet; 5 Exhaust port; 6 Sampling pump; 7 Flow control module, 71 Pulse proportional valve, 72 Air filter element; 8 Absolute pressure sensor. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0022] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] At present, gas analyzers are mostly used to analyze and measure the gas components in engine exhaust. However, due to factors such as the activity of gas components in exhaust gas, the entire system must be kept in a high temperature constant temperature state (above 190°C) to avoid condensation, adsorption and other factors that may reduce measurement accuracy.

[0024] However, in the prior art, there are gas analyzers that use a mid-mounted sampling pump or a post-mounted sampling pump. Among them, the mid-mounted sampling pump refers to a sampling pump located between the sampling pipeline and the core sensor in the gas circuit of the gas analyzer equipment, that is, when sampling, the sampling tube part is in a negative pressure state, and the pressure between the sampling pump and the measuring sensor and the exhaust port is positive; while the post-mounted sampling pump refers to a sampling pump arranged at the end of the entire gas circuit in the gas circuit of the gas analyzer equipment, located at the rear end of the sampling pipeline and the core measuring sensor and before the exhaust port of the equipment. In this way, the entire system before the sampling pump is in a negative pressure state, and the gas analyzer may have a sampling state and a calibration state. In the calibration state and the sampling state, different gas flow rates are required, so the differential pressure on both sides of the core sensor is different. If the flow pressure on both sides of the core sensor is unstable, it may interfere with the measurement, so there is a problem of unstable measurement accuracy, which affects the accuracy of the gas analyzer.

[0025] like Figure 1As shown, an embodiment of the present application provides a high-temperature gas flow control system for a gas analyzer, including a core sensor 2, wherein the input end of the core sensor 2 is connected to a sample gas inlet 3 and a standard gas inlet 4, and the output end of the core sensor 2 is connected to an exhaust port 5; further comprising: a sampling pump 6: arranged between the core sensor 2 and the exhaust port 5; a flow control module 7: arranged at the input end of the sampling pump 6, capable of controlling the gas flowing in through the sample gas inlet 3 and / or the standard gas inlet 4 to flow into the sampling pump 6 when the sampling pump 6 is turned on, so as to control the gas flow flowing through the core sensor 2; a main control system 1: respectively connected to the core sensor 2 and the flow control module 7.

[0026] Specifically, the flow control module 7 is set at the input end of the sampling pump 6, and can control the air to flow into the sampling pump 6 when the sampling pump 6 is turned on. Therefore, when the sampling pump 6 is turned on, the air can be sucked in by the flow control module 7, so that the sample gas or standard gas flows into the core sensor 2 at a relatively stable flow rate, so that the pressure difference at both ends of the core sensor 2 is kept as stable as possible, which solves the problem that the gas flow rate is different in the calibration state and the sampling state, resulting in different differential pressures on both sides of the core sensor 2, thereby interfering with the measurement, and greatly improves the analysis accuracy of the gas analyzer. In addition, the use of a post-type sampling pump 6 greatly reduces the requirements for the sampling pump 6 compared to the special high-performance requirements of the mid-type sampling pump 6, which must be self-heated and high-temperature resistant.

[0027] As an optional implementation, a differential pressure sensor 21 is further included, and two ends of the differential pressure sensor 21 are respectively connected to two ends of the core sensor 2 and to the main control system 1 for obtaining the gas pressure difference at both ends of the core sensor 2 .

[0028] Specifically, a differential pressure sensor 21 is also provided, and the differential pressure sensor 21 can obtain the differential pressure at both ends of the core sensor 2 in real time or at a fixed time, and can promptly feed back to the main control system 1, so that the technician can promptly obtain the differential pressure at both ends of the core sensor 2, and then the technician or the main control system 1 can further control the flow rate according to the differential pressure, thereby further improving the measurement accuracy of the gas analyzer and improving the intelligence level of the control system.

[0029] As an optional embodiment, the flow control module 7 includes: a pulse proportional valve 71 and an air filter 72. The air filter 72 is connected to the input end of the sampling pump 6 through the pulse proportional valve 71. The pulse proportional valve 71 is also connected to the main control system 1 for controlling the amount of clean gas entering the sampling pump 6 through the flow control module 7.

[0030] As an optional implementation, the main control system 1 is configured to control the opening of the pulse proportional valve 71 according to the measurement value of the differential pressure sensor 21 .

[0031] Specifically, the flow control module 7 includes a pulse proportional valve 71 and an air filter 72. When the sampling pump 6 is running, if it is necessary to control the gas flow to keep the differential pressure at both ends of the core sensor 2 stable, the opening of the pulse proportional valve 71 can be controlled according to the differential pressure at both ends of the core sensor 2 and the air extraction amount of the sampling pump 6 to control the flow of the clean gas filtered by the air filter 72, so that the gas extracted by the sampling pump 6 is the gas and clean gas that pass through the core sensor 2. The pulse proportional valve 71 and the air filter 72 are low in cost, easy to use, and small in size.

[0032] As an optional implementation, it also includes an absolute pressure sensor 8, both ends of which are connected to the output ends of the main control system 1 and the core sensor 2 respectively, and can obtain the output end pressure of the core sensor 2 to monitor the gas path.

[0033] As an optional implementation, the main control system 1 is configured to output an alarm signal when the measurement value of the absolute pressure sensor 8 is lower than the atmospheric pressure or higher than a preset maximum value.

[0034] Specifically, if there is an abnormality in the entire air path, such as a blockage, the airflow of the entire system cannot circulate normally. At this time, even if the sampling pump 6 is pumping air at full load, it may not be able to reach the target flow rate. At this time, the measurement value of the absolute pressure sensor 8 will be much lower than the atmospheric pressure. Therefore, the main control system 1 obtains the excessively low pressure feedback from the absolute pressure sensor 8, and can output a signal for alarm or remedial measures to prevent the sampling pump 6 from being overloaded for a long time and affecting its life. In addition, when the sampling pump 6 fails to operate, the measurement value of the absolute pressure sensor 8 will be high. Similarly, when the main control system 1 obtains the high pressure value emitted by the absolute pressure sensor 8, it can promptly remind the technician or take remedial measures, thereby improving the intelligence of the control system.

[0035] As an optional embodiment, the high-temperature gas flow control system for the gas analyzer includes a sampling state and a calibration state. In the sampling state, the sample gas inlet 3 is opened and the standard gas inlet 4 is closed; in the calibration state, the standard gas inlet 4 is opened and the sample gas inlet 3 is closed.

[0036] As an optional implementation, it further includes a flow meter, which is arranged at the exhaust port 5 and connected to the main control system 1 .

[0037] As an optional implementation, the main control system 1 is configured to perform multi-point data fitting based on the flow meter measurement value and the differential pressure sensor 21 measurement value to obtain a fitting formula between the differential pressure sensor 21 measurement value and the flow meter measurement value.

[0038] By measuring the flow rate at the exhaust port 5 by the flowmeter and the multi-point fitting data of the differential pressure at both ends of the core sensor 2 measured by the differential pressure sensor 21, a multi-factor fitting formula between the pressure value and the flow rate can be calibrated: F=A*P2+B*P+C, wherein F is the actual flow rate of the equipment, A is the quadratic term coefficient, B is the linear term coefficient, C is the constant term, and P is the differential pressure measured by the differential pressure sensor 21. The relationship between the flow rate and the differential pressure can be determined, thereby determining the gas flow rate required by the core sensor 2.

[0039] As an optional implementation, the flow control module 7 includes a high temperature resistant pulse solenoid valve, which is arranged between the core sensor 2 and the input end of the sampling pump 6 and is used to control the gas flow of the gas path of the sampling pump 6 .

[0040] Exemplarily, the main control system 1 can be set to collect the pressure value P of the differential pressure sensor 21 in real time, and convert it into a flow value through the above formula F=A*P2+B*P+C; the main control system 1 is programmed with a control algorithm based on a PID closed loop, in which the flow value F is a feedback value, and the flow demand under different equipment states is the target value of the PID algorithm (F1: measured flow target value F2: calibrated flow target value Fn: other state flow target value); the pulse proportional valve 71 is the output execution hardware of the PID algorithm, and the duty cycle control characteristics of the pulse proportional valve 71 have the characteristics of high response and high accuracy, so it is more consistent with the pressure flow control of small flow dynamics. When the device is in a certain state, the PID adjusts the PID output value in real time according to the feedback of the target flow Fn and the actual flow F at this time. This value corresponds to the pulse width value of the pulse proportional valve 71, that is, the proportional valve adjusts its opening in real time according to the instruction, so as to achieve a relatively stable flow through the core sensor 2, so as to achieve the pressure flow control of the high-temperature gas in the control system and ensure the accuracy of the gas component measurement.

[0041] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0042] If the integrated units in the above embodiments are implemented in the form of software functional units and sold or used as independent products, they can be stored in the above computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling one or more electronic devices (such as personal computers, servers, or network devices) to perform all or part of the steps of the methods described in the various embodiments of the present application.

[0043] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0044] In the several embodiments provided in the present application, it should be understood that the disclosed client can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0045] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution provided in this embodiment.

[0046] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0047] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0048] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A high temperature gas flow control system for a gas analyzer, characterized in that: The invention comprises a core sensor (2), wherein the input end of the core sensor (2) is connected to a sample gas inlet (3) and a standard gas inlet (4), and the output end of the core sensor (2) is connected to an exhaust port (5); and further comprises: A sampling pump (6) is arranged between the core sensor (2) and the exhaust port (5); A flow control module (7) is arranged at the input end of the sampling pump (6) and is capable of controlling the gas flowing in through the sample gas inlet (3) and / or the standard gas inlet (4) to flow into the sampling pump (6) when the sampling pump (6) is turned on, so as to control the gas flow passing through the core sensor (2); Main control system (1): connected to the core sensor (2) and the flow control module (7) respectively.

2. The high temperature gas flow control system for a gas analyzer according to claim 1, characterized in that: It also comprises a differential pressure sensor (21), the two ends of which are respectively connected to the two ends of the core sensor (2), and connected to the main control system (1), for obtaining the gas pressure difference at the two ends of the core sensor (2).

3. The high temperature gas flow control system for a gas analyzer according to claim 2, characterized in that: The flow control module (7) comprises: a pulse proportional valve (71) and an air filter element (72); the air filter element (72) is connected to the input end of the sampling pump (6) via the pulse proportional valve (71); the pulse proportional valve (71) is also connected to the main control system (1) and is used to control the amount of clean gas entering the sampling pump (6) through the flow control module (7).

4. The high temperature gas flow control system for a gas analyzer according to claim 3, characterized in that: The main control system (1) is configured to control the opening degree of the pulse proportional valve (71) according to the measurement value of the differential pressure sensor (21).

5. The high temperature gas flow control system for a gas analyzer according to claim 1, characterized in that: It also includes an absolute pressure sensor, the two ends of which are respectively connected to the output ends of the main control system (1) and the core sensor (2), and can obtain the pressure at the output end of the core sensor (2) to monitor the gas path.

6. The high temperature gas flow control system for a gas analyzer according to claim 5, characterized in that: The main control system (1) is configured to output an alarm signal when the value measured by the absolute pressure sensor is lower than the atmospheric pressure or higher than a preset maximum value.

7. The high temperature gas flow control system for a gas analyzer according to claim 1, characterized in that: It comprises a sampling state and a calibration state. In the sampling state, the sample gas inlet (3) is opened and the standard gas inlet (4) is closed; in the calibration state, the standard gas inlet (4) is opened and the sample gas inlet (3) is closed.

8. The high temperature gas flow control system for a gas analyzer according to claim 2, characterized in that: It also includes a flow meter, which is arranged at the exhaust port (5) and connected to the main control system (1).

9. The high temperature gas flow control system for a gas analyzer according to claim 8, characterized in that: The main control system (1) is configured to perform multi-point data fitting based on the flow meter measurement value and the differential pressure sensor (21) measurement value, so as to obtain a fitting formula between the differential pressure sensor (21) measurement value and the flow meter measurement value.

10. The high temperature gas flow control system for a gas analyzer according to claim 1, characterized in that: The flow control module (7) comprises a high temperature resistant pulse electromagnetic valve, which is arranged between the core sensor (2) and the input end of the sampling pump (6) and is used to control the gas flow of the gas path of the sampling pump (6).

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