R290 refrigerant gas leakage detection method and R290 refrigerant gas leakage detection device

Abstract

The invention discloses an R290 refrigerant gas leakage detection method and device, and the method comprises the steps: obtaining the state information of a reflecting surface in an infrared gas chamber in an infrared sensor, and enabling the state information to comprise a non-condensation / frosting state and a condensation / frosting state; if the reflecting surface is in the non-condensation / frosting state, an infrared sensor is adopted to detect whether R290 refrigerant gas exists in an infrared gas chamber of the reflecting surface or not, a first signal is output to a controller when the R290 refrigerant gas is detected, and if the reflecting surface is in the condensation / frosting state, an auxiliary sensor is adopted to detect whether the R290 refrigerant gas exists or not, and a second signal is output to the controller when the R290 refrigerant gas is detected; the auxiliary sensor is used for detecting the R290 refrigerant gas and outputting a second signal to the controller when detecting the R290 refrigerant gas, the detection principle of the auxiliary sensor is different from that of the infrared sensor, and the detection principle adopted by the auxiliary sensor is not influenced by condensation / frosting; in this way, the R290 refrigerant gas can be effectively detected, and meanwhile it is ensured that power consumption is not too high.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection, and in particular to an R290 refrigerant gas leakage detection method and an R290 refrigerant gas leakage detection device. Background Art

[0002] As a necessary product for controlling thermal comfort, refrigerants are widely used in refrigerators, industrial refrigeration, air conditioners and many other applications. R290 (A3) is a member of the new green and environmentally friendly refrigerants. Its damage to the ozone layer is much less than R22. Today, as the global call for protecting the ozone layer is growing, the development of new refrigerants is of great significance.

[0003] Since R290 refrigerant gas is flammable and explosive, if it leaks during use, the concentration in the local environment will reach the combustion ratio, which will pose a serious threat to life and property. Therefore, it is necessary to detect the R290 refrigerant gas concentration in the use environment in real time and have an alarm function.

[0004] The application of thermal conductivity gas sensors in the field of refrigerant leakage detection has the characteristics of small size, high reliability, no impact from condensation and frosting environment, and fast response time; however, there is a defect of poor detection accuracy for R290 refrigerant gas with low explosion limit and thermal conductivity close to that of air.

[0005] Ultrasonic gas sensing technology uses the principle of measuring the speed of sound of ultrasonic wave propagation, and then measures the average molecular weight of the gas, and then calculates the concentration of the gas to be measured. It has the advantages of small size, low power consumption, fast response time and long life. However, this detection principle also has the defect of poor detection accuracy for R290 refrigerant gas with a low explosion limit and a molecular mass close to the average molecular weight of air.

[0006] The NDIR infrared gas sensor is a sensor that uses the infrared absorption principle to detect gas concentration and is highly selective. By selecting different filters, a variety of gases can be detected to meet different application requirements, and it has high sensitivity and can detect extremely low concentrations of gas. In addition, the NDIR sensor has the characteristics of fast response time and long life, and can detect R290 refrigerant gas. As in patent CN221549928U, the applicant found that when used in the field of air conditioning, the NDIR infrared gas sensor is affected by the condensation / frosting caused by the rapid temperature changes of some refrigeration systems. The sensor needs to add heating and insulation functions to prevent condensation / frosting, but this will increase the size and power consumption of the sensor, resulting in limited sensor applications.

[0007] In addition, MOX sensors, electrochemical sensors and thermocatalytic sensors can also detect R290 refrigerant gas. However, the sensitivity of MOX sensors decreases as their usage time increases, while electrochemical sensors and thermocatalytic sensors have a short service life. Summary of the invention

[0008] The main purpose of the present invention is to provide an R290 refrigerant gas leakage detection method and an R290 refrigerant gas leakage detection device with improved detection reliability.

[0009] To achieve the above object, the present invention provides a method for detecting R290 refrigerant gas leakage, comprising the following steps: Step S1, obtaining state information of a reflective surface in an infrared chamber of an infrared sensor, wherein the state information includes a non-condensed / frosted state and a condensed / frosted state; Step S2: If the reflecting surface is in the non-condensing / frosting state, the infrared sensor is used to detect in real time whether there is R290 refrigerant gas in its infrared air chamber, and a first signal is output to the controller when the R290 refrigerant gas is detected; if the reflecting surface is in the condensing / frosting state, an auxiliary sensor is used to detect in real time whether there is R290 refrigerant gas, and a second signal is output to the controller when the R290 refrigerant gas is detected; wherein the detection principle of the auxiliary sensor is different from the detection principle of the infrared sensor, and the detection principle adopted by the auxiliary sensor is not affected by condensation / frosting.

[0010] The present invention also provides an R290 refrigerant gas leakage detection device, which is applicable to the R290 refrigerant gas leakage detection method. The R290 refrigerant gas leakage detection device comprises: The shell is provided with an air inlet for allowing the gas to be tested to enter the shell; An infrared sensor is disposed in the housing, and its infrared air chamber is connected to the air inlet so that the gas to be tested can pass through for detection; an auxiliary sensor, disposed in the housing and connected to the air inlet, for detecting whether R290 refrigerant gas exists in the gas to be tested, wherein the detection principle of the auxiliary sensor is different from that of the infrared sensor, and the detection principle adopted by the auxiliary sensor is not affected by condensation / frosting; and, The controller is electrically connected to the infrared sensor and the auxiliary sensor, and is used to obtain the state information of the reflective surface in the infrared air chamber, and receive the first signal of the infrared sensor or the second signal of the auxiliary sensor according to the state information.

[0011] In the technical solution of the present invention, according to the state information of the reflecting surface in the infrared gas chamber of the infrared sensor, when the reflecting surface is in a non-condensing / frosting state, the infrared sensor is selected to detect in real time whether there is R290 refrigerant gas; when the reflecting surface is in a condensing / frosting state, an auxiliary sensor whose detection principle is different from that of the infrared sensor and whose detection principle is not affected by condensation / frosting can be used to detect in real time whether there is R290 refrigerant gas. In this way, the infrared sensor and the auxiliary sensor are combined to detect whether R290 refrigerant gas leakage occurs, that is, when the reflecting surface is in the condensing / frosting state that affects the measurement of the infrared sensor, the auxiliary sensor is used for detection and outputs a second signal to the controller, thereby solving the problem of the infrared sensor being affected by condensation / frosting caused by rapid changes in temperature and humidity in the refrigeration system and the large size and high power consumption caused by adding a heating circuit to prevent condensation and frosting. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 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, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0013] Figure 1 A flow chart of the R290 refrigerant gas leakage detection method provided by the present invention; Figure 2 This is a flow chart of an embodiment of step S111; Figure 3 is a flowchart of another embodiment of step S111; Figure 4 A schematic structural diagram of an embodiment of an R290 refrigerant gas leakage detection device provided by the present invention (the auxiliary device is a thermal conductivity sensor); Figure 5 A schematic diagram of another embodiment of the R290 refrigerant gas leakage detection device provided by the present invention (the auxiliary device is an acoustic resonance ultrasonic sensor) Description of Figure Numbers: 100. R290 refrigerant gas leakage detection device; 1. housing, 11. upper cover, 111. air inlet; 12. lower cover; 2. Infrared sensor; 3. Auxiliary sensor; 4. Waterproof and breathable membrane; 5. Electromagnetic shielding cover.

[0014] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0017] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0018] The NDIR infrared gas sensor is a sensor that uses the principle of infrared radiation to detect gas concentration and is highly selective. By selecting different filters, a variety of gases can be detected to meet different application requirements, and it has high sensitivity and can detect extremely low concentrations of gas. In addition, the NDIR sensor has the characteristics of fast response time and long life, and can detect R290 refrigerant gas. As in patent CN221549928U, the applicant found that when used in the field of air conditioning, the NDIR infrared gas sensor is affected by condensation / frosting caused by rapid temperature changes in some refrigeration systems. The sensor needs to add heating and insulation functions to prevent condensation / frosting, but this will increase the size and power consumption of the sensor, resulting in limited sensor applications.

[0019] In view of this, the present invention provides a method for detecting leakage of R290 refrigerant gas. Figures 1 to 3The present invention provides a flow chart of the R290 refrigerant gas leakage detection method.

[0020] See also Figure 1 , the R290 refrigerant gas leakage detection method comprises the following steps: Step S1, obtaining state information of a reflective surface in an infrared chamber of an infrared sensor, wherein the state information includes a non-condensation / frosting state and a condensation / frosting state.

[0021] Step S2: If the reflecting surface is in the non-condensing / frosting state, the infrared sensor is used to detect in real time whether there is R290 refrigerant gas in its infrared gas chamber, and a first signal is output to the controller when the R290 refrigerant gas is detected. If the reflecting surface is in the condensing / frosting state, an auxiliary sensor is used to detect in real time whether there is R290 refrigerant gas, and a second signal is output to the controller when the R290 refrigerant gas is detected, wherein the detection principle of the auxiliary sensor is different from the detection principle of the infrared sensor, and the detection principle adopted by the auxiliary sensor is not affected by condensation / frosting.

[0022] In the technical solution of the present invention, according to the state information of the reflecting surface in the infrared gas chamber of the infrared sensor, when the reflecting surface is in a non-condensing / frosting state, the infrared sensor is selected to detect in real time whether there is R290 refrigerant gas; when the reflecting surface is in a condensing / frosting state, an auxiliary sensor whose detection principle is different from that of the infrared sensor and whose detection principle is not affected by condensation / frosting can be used to detect in real time whether there is R290 refrigerant gas. In this way, the infrared sensor and the auxiliary sensor are combined to detect whether R290 refrigerant gas leakage occurs, that is, when the reflecting surface is in the condensing / frosting state that affects the measurement of the infrared sensor, the auxiliary sensor is used for detection and outputs a second signal to the controller, thereby solving the problem of the infrared sensor being affected by condensation / frosting caused by rapid changes in temperature and humidity in the refrigeration system and the large size and high power consumption caused by adding a heating circuit to prevent condensation and frosting.

[0023] Furthermore, the auxiliary sensor is a thermal conductivity sensor, an acoustic resonance ultrasound sensor, a photoacoustic spectroscopy sensor, a MOX sensor, an electrochemical sensor or a thermal catalytic sensor.

[0024] It should be noted that, since the practicality of the MOX sensor, the electrochemical sensor and the thermocatalytic sensor is limited by the use time, when the reflecting surface is in the condensation / frosting state, the MOX sensor, the electrochemical sensor or the thermocatalytic sensor is in the on state, and when the reflecting surface is in the non-condensation / frosting state, the MOX sensor, the electrochemical sensor or the thermocatalytic sensor is in the off state. In other words, the MOX sensor, the electrochemical sensor and the thermocatalytic sensor are turned on and used only when the reflecting surface is in the condensation / frosting state.

[0025] The thermal conductivity sensor, acoustic resonance ultrasonic sensor, and photoacoustic spectroscopy sensor themselves have a long service life, and their sensitivity is less affected by the use time. Therefore, when the auxiliary sensor is one of the thermal conductivity sensor, acoustic resonance ultrasonic sensor, and photoacoustic spectroscopy sensor, the auxiliary sensor can be used intermittently, that is, when the reflecting surface is in the non-condensed / frosted state, the infrared sensor is used for detection, and the auxiliary sensor is in a closed state; when the reflecting surface is in the condensed / frosted state, the auxiliary sensor is in an open state for detection; of course, the auxiliary sensor can also start detection at the same time as the infrared sensor, which can be used to verify the detection results of the infrared sensor.

[0026] In some embodiments of the present invention, step S2 specifically includes: Step S21', start the infrared sensor and the auxiliary sensor to detect in real time whether there is R290 refrigerant gas. If the reflecting surface is in the non-condensing / frosting state, the infrared sensor outputs the first signal to the controller when detecting the R290 refrigerant gas. If the reflecting surface is in the condensing / frosting state, the auxiliary sensor outputs the second signal to the controller when detecting the R290 refrigerant gas.

[0027] In this way, the detection result of the infrared sensor can be synchronously verified in combination with the auxiliary sensor, that is, when the infrared sensor detects that the R290 refrigerant gas concentration value reaches the detection accuracy of the auxiliary sensor, the auxiliary sensor is used to verify whether R290 refrigerant gas exists, and then the result is output as needed. It should be noted that the output result at this time can be flexibly configured in the actual product. For example, when the auxiliary sensor detects R290 refrigerant gas, the algorithm remains unchanged. When the auxiliary sensor does not detect refrigerant gas, the data can be recorded for subsequent analysis, or the output of the first signal can be stopped.

[0028] In some other embodiments of the present invention, step S2 specifically includes: Step S21'', if the reflecting surface is in the non-condensing / frosting state, the infrared sensor is used to detect in real time whether there is R290 refrigerant gas in its infrared gas chamber, and the first signal is output to the controller when the R290 refrigerant gas is detected, and after the R290 refrigerant gas concentration value detected by the infrared sensor reaches the auxiliary sensor detection accuracy, the auxiliary sensor is started to detect in real time whether there is R290 refrigerant gas, and the detected second signal is output to the controller, if the reflecting surface is in the condensing / frosting state, the auxiliary sensor is used to detect in real time whether there is R290 refrigerant gas, and the second signal is output to the controller when the R290 refrigerant gas is detected.

[0029] In this way, not only the startup time of the auxiliary sensor can be reduced, but also the detection result of the infrared sensor can be synchronously verified in combination with the auxiliary sensor, which will not be elaborated here.

[0030] Specifically, the step S1 specifically includes: Step S11: acquiring status information of the reflective surface according to the infrared sensor and / or the temperature and humidity sensor.

[0031] That is to say, in the present invention, the state information of the reflective surface can be obtained according to either the infrared sensor or the temperature and humidity sensor, or the state information of the reflective surface can be obtained in combination with the infrared sensor and the temperature and humidity sensor.

[0032] Furthermore, in the first embodiment of the present invention, the infrared sensor is a dual-channel infrared sensor having a first detector corresponding to a detection channel and a second detector corresponding to a reference channel. The filter provided in the detection channel can filter light of a band absorbed by the R290 refrigerant gas, and the filter provided in the reference channel can filter light of a band that is not absorbed by any gas that is present in the application scenario of the detection device of this embodiment and that may be produced. The first signal change rate x1 of the optical signal received by the first detector at least reflects the change of the R290 refrigerant gas, and the second signal change rate x2 of the optical signal received by the second detector at least reflects the change of the environment. In this way, the state information of the reflective surface in the infrared air chamber can be directly obtained through the infrared sensor.

[0033] The step S11 specifically includes: Step S111, obtaining the state information of the reflecting surface at least according to the second signal change rate x2.

[0034] Furthermore, the state information of the reflecting surface may be further obtained through the change values ​​of the first signal change rate x1 and the second signal change rate x2 and respective differences.

[0035] See also Figure 2 , the step S111 specifically includes: Step S1111, obtaining the first signal change rate x1 and the second signal change rate x1.

[0036] Step S1112: within the first preset time, if the light signal received by the first detector and the light signal received by the second detector both decrease, and x1<λ1, x2<λ1 and |x1-x2|<λ2, it is determined that a temperature change occurs in the infrared air chamber and the reflecting surface is in the non-condensing / frosting state; within the first preset time, if the light signal received by the first detector and the light signal received by the second detector both decrease, and x1<λ1, x2<λ1 and |x1-x2|>λ2, it is determined that a temperature change occurs in the infrared air chamber and the reflecting surface is in the non-condensing / frosting state, and R290 refrigerant gas exists; within the second preset time, if the light signal received by the first detector and the light signal received by the second detector both decrease, and x1<λ1, x2<λ1 and |x1-x2|>λ2, it is determined that a temperature change occurs in the infrared air chamber and the reflecting surface is in the non-condensing / frosting state, and R290 refrigerant gas exists. If the optical signal received by the first detector and the optical signal received by the second detector both decrease and |x1-x2|<λ2, and the rate of change x2 of the second signal increases and x2>λ3 within the third preset time, it is judged that the reflecting surface is in the condensation / frosting state; if the optical signal received by the first detector and the optical signal received by the second detector both decrease and |x1-x2|<λ2 within the second preset time, and change to x1>x2>λ3 within the third preset time, it is judged that the reflecting surface is in the condensation / frosting state, and R290 refrigerant gas is suspected to exist; wherein λ1 is the first preset threshold, λ2 is the second preset threshold, λ3 is the third preset threshold, and λ2<λ1<λ3.

[0037] It should be noted that the light signal received by the first detector and the light signal received by the second detector both decrease, and x1<λ1, x2<λ1 and |x1-x2|<λ2, that is, the light signal received by the first detector and the light signal received by the second detector both decrease, and the change rates of the two signals are small and close (that is, basically the same). At this time, it can be judged that the temperature changes in the infrared air chamber and the reflecting surface is in the non-condensed / frosted state.

[0038] The light signal received by the first detector and the light signal received by the second detector both decrease, and x1<λ1, x2<λ1 and |x1-x2|>λ2, that is, the light signal received by the first detector and the light signal received by the second detector both decrease, and the change rates of the two signals are quite different. At this time, it can be determined that the temperature changes in the infrared air chamber and the reflecting surface is in the non-condensed / frosted state. At the same time, it also indicates that the infrared sensor detects R290 refrigerant gas, that is, R290 refrigerant gas exists.

[0039] Within the second preset time, the optical signal received by the first detector and the optical signal received by the second detector both decrease and |x1-x2|<λ2, and within the third preset time, the second signal change rate x2 increases and x2>λ3, that is, the optical signal received by the first detector and the optical signal received by the second detector both decrease, and within the second preset time, the two signal change rates are close (that is, basically the same), but within the third preset time, the first signal change rate x1 suddenly increases and is greater than the third preset threshold λ3. At this time, it can be determined that the reflective surface is in the condensation / frosting state.

[0040] Within the second preset time, the optical signal received by the first detector and the optical signal received by the second detector both decrease and |x1-x2|<λ2, and within the third preset time, they change to x1>x2>λ3, that is, the optical signal received by the first detector and the optical signal received by the second detector both decrease, and within the second preset time, the change rates of the two signals are close (that is, basically the same), but within the third preset time, the first signal change rate x1 and the second signal change rate x2 both suddenly increase to be greater than λ3, and the first signal change rate x1 is greater than the second signal change rate x2. At this time, it can be determined that the reflective surface is in the condensation / frosting state. At the same time, it also indicates that the infrared sensor may have detected R290 refrigerant gas, that is, R290 refrigerant gas is suspected to exist.

[0041] In addition, when the light signal received by the first detector decreases, while the light signal received by the second detector remains substantially unchanged, it indicates that the infrared sensor may have detected R290 refrigerant gas.

[0042] Specifically, in another embodiment of the present invention, a temperature sensor is further provided; The step S111 specifically includes: Step S1111', obtaining the first signal change rate x1 and the second signal change rate x2; Step S1112', within the first preset time, the temperature change detected by the temperature sensor is greater than or equal to the fourth preset threshold value, if the light signal received by the second detector decreases, and x2<λ1, it is judged that the temperature change occurs in the infrared air chamber and the reflecting surface is in the non-condensing / frosting state, if the light signal received by the second detector decreases within the second preset time, and within the third preset time, the second signal change rate x2 increases and x2>λ3, it is judged that the reflecting surface is in the condensing / frosting state; If the temperature change detected by the temperature sensor is less than the fourth preset threshold, it is determined that the reflective surface is in the non-condensation / frosting state.

[0043] It should be noted that the first preset time can be set to 30s, 60s, 90s, etc., the second preset time and the third preset time are within the first preset time, and the first preset time is greater than or equal to the sum of the second preset time and the third preset time.

[0044] Specifically, in the second embodiment of the present invention, the step S11 specifically includes: Step S111': using the temperature and humidity sensor to obtain the ambient temperature and humidity.

[0045] Step S112': within the first preset time, if the ambient temperature rises from below zero to zero degrees Celsius or above, and the air has a certain humidity, it is judged that the reflecting surface is in a frosted state; if the ambient temperature rises from a temperature above zero degrees Celsius and the ambient humidity is greater than or equal to the condensation humidity critical point at this temperature, it is judged that the reflecting surface is in a condensed state.

[0046] It should be noted that, at a certain temperature, the humidity in the air reaches a preset value and enters a condensation state, and the preset value is the condensation humidity critical point.

[0047] In addition, when the state information of the reflective surface is obtained according to the temperature and humidity sensor, the infrared sensor may be used for verification to confirm the actual state of the reflective surface.

[0048] Therefore, in the third embodiment of the present invention, the infrared sensor is a dual-channel infrared sensor having a first detector corresponding to a detection channel and a second detector corresponding to a reference channel; the state information also includes a suspected condensation / frosting state; and the step S11 specifically includes: Step S111'', judging the state of the reflecting surface according to the ambient temperature and humidity detection results of the temperature and humidity sensor to obtain a first state judgment result, and judging the state of the reflecting surface according to at least the second signal change rate x2 of the light signal received by the second detector to obtain a second state judgment result.

[0049] It should be noted that, in this step, the specific steps of obtaining the first state judgment result according to the temperature and humidity sensor are basically the same as the steps S111' and S112' described above, and therefore, they are not described one by one. Similarly, in this step, the specific steps of obtaining the second state judgment result according to the first signal change rate x1 of the optical signal received by the first detector and the second signal change rate x2 of the optical signal received by the second detector are basically the same as the steps S1111 and S1112 described above, and therefore, they are not described one by one.

[0050] Step S112'': if both the first state judgment result and the second state judgment result are that the reflective surface is in the condensation / frosting state, confirming that the reflective surface is in the condensation / frosting state; If the first state judgment result is in a non-condensation / frosting state, and the second state judgment result is in a condensation / frosting state, confirming that the reflective surface is in the suspected condensation / frosting state; If the first state judgment result is that the reflective surface is in the condensation / frosting state, and the second state judgment result is that the reflective surface is not in the condensation / frosting state, then confirming that the reflective surface is in the suspected condensation / frosting state; If both the first state judgment result and the second state judgment result are not in the condensation / frosting state, it is confirmed that the infrared air chamber is in the non-condensation / frosting state.

[0051] In this way, by combining the first state judgment result and the second state judgment result for comprehensive judgment, more accurate state information of the reflecting surface can be obtained, thereby improving the accuracy of the R290 refrigerant gas leakage detection result.

[0052] Furthermore, the step S2 specifically includes: Step S21: If the reflecting surface is in the non-condensing / frosting state, the infrared sensor is used to detect in real time whether there is R290 refrigerant gas in its infrared gas chamber, and the first signal is output to the controller when the R290 refrigerant gas is detected; if the reflecting surface is in the confirmed condensation / frosting state, the auxiliary sensor is used to detect in real time whether there is R290 refrigerant gas, and the second signal is output to the controller when the R290 refrigerant gas is detected; if the reflecting surface is in the suspected condensation / frosting state, when the infrared sensor does not detect the R290 refrigerant gas, no signal is output; when the infrared sensor detects the R290 refrigerant gas and the auxiliary sensor does not detect the R290 refrigerant gas, no signal is output; when the infrared sensor detects the R290 refrigerant gas and the auxiliary sensor detects the R290 refrigerant gas, the second signal is output to the controller.

[0053] That is to say, in the third embodiment of the present invention, when it is determined that the reflecting surface is in the non-condensing / frosting state, the first signal obtained by detection by the infrared sensor is output to the controller, and when it is determined that the reflecting surface is in the condensing / frosting state, the second signal obtained by detection by the auxiliary sensor is output to the controller, and when the reflecting surface is in the suspected condensing / frosting state, both the infrared sensor and the auxiliary sensor perform real-time detection, but when the infrared sensor or the auxiliary sensor does not detect the R290 refrigerant gas, no signal is output, and when both the infrared sensor and the auxiliary sensor detect the R290 refrigerant gas, the second signal is output.

[0054] The present invention further provides an R290 refrigerant gas leakage detection device 100, which is applicable to the R290 refrigerant gas leakage detection method described above.

[0055] For details, please refer to Figure 4 and Figure 5 The R290 refrigerant gas leakage detection device 100 includes a shell 1, an infrared sensor 2, an auxiliary sensor 3 and a controller. The shell 1 is provided with an air inlet 111 for the gas to be tested to pass into the shell 1; the infrared sensor 2 is arranged in the shell 1, and its infrared air chamber is connected with the air inlet 111 for the gas to be tested to pass into the detection; the auxiliary sensor 3 is arranged in the shell 1 and is connected with the air inlet 111 to detect whether there is R290 refrigerant gas in the gas to be tested. The detection principle of the auxiliary sensor 3 is different from that of the infrared sensor 2, and the auxiliary sensor 3 is not affected by condensation / frost; the controller is electrically connected to the infrared sensor 2 and the auxiliary sensor 3, and is used to obtain the state information of the reflective surface in the infrared air chamber, and receive the first signal of the infrared sensor 2 or the second signal of the auxiliary sensor 3 according to the state information.

[0056] In this way, the leakage of R290 refrigerant gas is detected by integrating the infrared sensor 2 and the auxiliary sensor 3. Specifically, the infrared sensor 2 is used as the main sensor and the auxiliary sensor 3 is used as the auxiliary sensor for detection. This can not only solve the problem that the infrared sensor 2 is affected by condensation and frosting caused by rapid changes in temperature and humidity in the refrigeration system, and that the heating circuit is increased to prevent condensation and frosting, but also solve the problem that the volume is large and the power consumption is high. In addition, the probability that the reflective surface is in the condensation / frosting state is small, and in the condensation / frosting state, the auxiliary sensor 3 can also detect the R290 refrigerant gas and output a signal value. The R290 refrigerant gas leakage detection device 100 provided by the present invention has the characteristics of low power consumption, long life, resistance to condensation / frosting interference, and high detection accuracy.

[0057] It should be noted that, in some embodiments of the present invention, the infrared sensor 2 is not only used to detect whether there is R290 refrigerant gas in the gas to be tested, but also can be used to detect the status information of the reflective surface in the infrared gas chamber.

[0058] It should also be noted that, in the present invention, the relative positions of the auxiliary sensor 3 and the infrared sensor 2 are not limited, and the auxiliary sensor 3 may be arranged outside the infrared sensor 2 (such as Figure 4 and Figure 5 As shown), at this time, the auxiliary sensor 3 detects the gas to be tested that is passed into the shell 1, or the auxiliary sensor 3 can be arranged in the infrared sensor 2. At this time, the auxiliary sensor 3 detects the gas to be tested that is passed into the infrared gas chamber.

[0059] It should also be noted that, in an embodiment of the present invention, a vent hole is provided on the housing 1 , an air intake grille is provided at the vent hole, and the air inlet 111 is formed on the air intake grille.

[0060] Furthermore, the controller executes the steps of the R290 refrigerant gas leakage detection method described above.

[0061] Specifically, the auxiliary sensor 3 is a thermal conductivity sensor (such as Figure 4 As shown), acoustic resonance ultrasonic sensor (such as Figure 5 as shown), MOX sensors, electrochemical sensors or thermocatalytic sensors.

[0062] Specifically, the R290 refrigerant gas leakage detection device 100 further includes a temperature and humidity sensor, which is disposed in the housing 1 and is used to detect the ambient temperature and humidity; the controller is electrically connected to the temperature and humidity sensor. In this way, the ambient temperature and humidity are detected by the temperature and humidity sensor, and the state information of the reflective surface can be obtained by combining the relationship between the ambient temperature and humidity and condensation / frosting.

[0063] More specifically, the infrared sensor 2 and the temperature and humidity sensor may be combined to obtain the state information of the reflective surface to improve accuracy.

[0064] For details, please refer to Figure 4 and Figure 5The shell 1 includes an upper cover 11 and a lower cover 12, and the upper cover 11 and the lower cover 12 are buckled and connected to form a accommodating cavity, and the air inlet 111 is arranged at the upper cover 11 or the lower cover 12; the R290 refrigerant gas leakage detection device 100 also includes a waterproof and breathable membrane 4 and at least one electromagnetic shielding cover 5, and the waterproof and breathable membrane 4 is arranged at the air inlet 111; the electromagnetic shielding cover 5 is arranged in the accommodating cavity, and the infrared sensor 2 and / or the auxiliary sensor 3 are arranged therein; the controller is arranged in the accommodating cavity.

[0065] In this way, the upper cover 11 and the lower cover 12 are snap-fitted and connected, which is convenient for installation or removal. By providing the waterproof and breathable membrane 4 at the air inlet 111, water can be prevented from entering the housing 1, thereby damaging the electronic components in the housing 1 and even causing safety accidents. At the same time, by providing the electromagnetic shielding cover 5, external electromagnetic interference can be effectively shielded, thereby improving the anti-interference performance of the infrared sensor 2 and the auxiliary sensor 3.

[0066] It should be noted that, in the present invention, the electromagnetic shielding cover 5 can be provided with one, and the infrared sensor 2 and the auxiliary sensor 3 are both provided in the electromagnetic shielding cover 5. Of course, two electromagnetic shielding covers can also be provided, and the infrared sensor 2 is provided in one of the two electromagnetic shielding covers 5, and the auxiliary sensor 3 is provided in the other.

[0067] Specifically, in one embodiment of the present invention, the first signal and the second signal include not only a concentration signal but also an alarm signal. To this end, the controller is also used to electrically connect to an external alarm to control the external alarm to operate after receiving the first signal or the second signal.

[0068] Of course, the controller may also be electrically connected to an external terminal to transmit the received first signal or the second signal to the external terminal.

[0069] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for detecting leakage of R290 refrigerant gas, characterized in that: The R290 refrigerant gas leakage detection method comprises the following steps: Step S1, obtaining state information of a reflective surface in an infrared chamber of an infrared sensor, wherein the state information includes a non-condensed / frosted state and a condensed / frosted state; Step S2: If the reflecting surface is in the non-condensing / frosting state, the infrared sensor is used to detect in real time whether there is R290 refrigerant gas in its infrared air chamber, and a first signal is output to the controller when the R290 refrigerant gas is detected; if the reflecting surface is in the condensing / frosting state, an auxiliary sensor is used to detect in real time whether there is R290 refrigerant gas, and a second signal is output to the controller when the R290 refrigerant gas is detected; wherein the detection principle of the auxiliary sensor is different from the detection principle of the infrared sensor, and the detection principle adopted by the auxiliary sensor is not affected by condensation / frosting.

2. The R290 refrigerant gas leakage detection method according to claim 1, characterized in that: The step S1 specifically includes: Step S11: acquiring status information of the reflective surface according to the infrared sensor and / or the temperature and humidity sensor.

3. The R290 refrigerant gas leakage detection method according to claim 2, characterized in that: The infrared sensor is a dual-channel infrared sensor, having a first detector corresponding to a detection channel and a second detector corresponding to a reference channel, wherein a first signal change rate x1 of the optical signal received by the first detector at least reflects a change in the R290 refrigerant gas, and a second signal change rate x2 of the optical signal received by the second detector at least reflects an environmental change; The step S11 specifically includes: Step S111, obtaining the state information of the reflecting surface at least according to the second signal change rate x2.

4. The R290 refrigerant gas leakage detection method according to claim 3, characterized in that: The step S111 specifically includes: Step S1111, obtaining the first signal change rate x1 and the second signal change rate x2; Step S1112: within a first preset time, if the optical signal received by the first detector and the optical signal received by the second detector both decrease, and x1<λ1, x2<λ1 and |x1-x2|<λ2, it is determined that a temperature change occurs in the infrared chamber and the reflective surface is in the non-condensed / frosted state; Within a first preset time, if the optical signal received by the first detector and the optical signal received by the second detector both decrease, and x1<λ1, x2<λ1 and |x1-x2|>λ2, it is determined that a temperature change occurs in the infrared chamber and the reflecting surface is in the non-condensed / frosted state, and R290 refrigerant gas exists; If the optical signal received by the first detector and the optical signal received by the second detector both decrease within the second preset time and |x1-x2|<λ2, and the second signal change rate x2 increases within the third preset time and x2>λ3, it is determined that the reflective surface is in the condensation / frosting state; If the optical signal received by the first detector and the optical signal received by the second detector both decrease within the second preset time and |x1-x2|<λ2, and change to x1>x2>λ3 within the third preset time, it is determined that the reflective surface is in the condensation / frosting state and R290 refrigerant gas is suspected to exist; Wherein, λ1 is a first preset threshold, λ2 is a second preset threshold, λ3 is a third preset threshold, and λ2<λ1<λ3.

5. The R290 refrigerant gas leakage detection method according to claim 3, characterized in that: A temperature sensor is also provided; The step S111 specifically includes: Step S1111', obtaining the first signal change rate x1 and the second signal change rate x2; Step S1112', within the first preset time, the temperature change detected by the temperature sensor is greater than or equal to the fourth preset threshold value, if the light signal received by the second detector decreases, and x2<λ1, it is judged that the temperature change occurs in the infrared air chamber and the reflecting surface is in the non-condensing / frosting state, if the light signal received by the second detector decreases within the second preset time, and within the third preset time, the second signal change rate x2 increases and x2>λ3, it is judged that the reflecting surface is in the condensing / frosting state; If the temperature change detected by the temperature sensor is less than the fourth preset threshold, it is determined that the reflective surface is in the non-condensation / frosting state.

6. The R290 refrigerant gas leakage detection method according to claim 2, characterized in that: The step S11 specifically includes: Step S111', using the temperature and humidity sensor to obtain the ambient temperature and humidity; Step S112': within the first preset time, if the ambient temperature rises from below zero to zero degrees Celsius or above, and there is humidity in the air, it is determined that the reflective surface is in a frosted state; within the first preset time, if the ambient temperature rises from a temperature above zero degrees Celsius and the ambient humidity is greater than or equal to the condensation humidity critical point at this temperature, it is determined that the reflective surface is in a condensed state.

7. The R290 refrigerant gas leakage detection method according to claim 2, characterized in that: The infrared sensor is a dual-channel infrared sensor having a first detector corresponding to a detection channel and a second detector corresponding to a reference channel; Also includes suspected condensation / frost conditions; The step S11 specifically includes: Step S111'', judging the state of the reflecting surface according to the ambient temperature and humidity detection result of the temperature and humidity sensor to obtain a first state judgment result, and judging the state of the reflecting surface according to at least a second signal change rate x2 of the light signal received by the second detector to obtain a second state judgment result; Step S112'': if the first state judgment result and the second state judgment result are both that the reflective surface is in the condensation / frosting state, confirming that the reflective surface is in the condensation / frosting state; If the first state judgment result is in a non-condensation / frosting state, and the second state judgment result is in a condensation / frosting state, confirming that the reflective surface is in the suspected condensation / frosting state; If the first state judgment result is that the reflective surface is in the condensation / frosting state, and the second state judgment result is that the reflective surface is not in the condensation / frosting state, then confirming that the reflective surface is in the suspected condensation / frosting state; If both the first state judgment result and the second state judgment result are not in the condensation / frosting state, it is confirmed that the infrared air chamber is in the non-condensation / frosting state.

8. The R290 refrigerant gas leakage detection method according to claim 7, characterized in that: The step S2 specifically includes: Step S21: If the reflecting surface is in the non-condensing / frosting state, the infrared sensor is used to detect in real time whether there is R290 refrigerant gas in its infrared gas chamber, and the first signal is output to the controller when the R290 refrigerant gas is detected; if the reflecting surface is in the confirmed condensation / frosting state, the auxiliary sensor is used to detect in real time whether there is R290 refrigerant gas, and the second signal is output to the controller when the R290 refrigerant gas is detected; if the reflecting surface is in the suspected condensation / frosting state, when the infrared sensor does not detect the R290 refrigerant gas, no signal is output; when the infrared sensor detects the R290 refrigerant gas and the auxiliary sensor does not detect the R290 refrigerant gas, no signal is output; when the infrared sensor detects the R290 refrigerant gas and the auxiliary sensor detects the R290 refrigerant gas, the second signal is output to the controller.

9. The R290 refrigerant gas leakage detection method according to claim 1, characterized in that: The auxiliary sensor is one of a thermal conductivity sensor, an acoustic resonance ultrasound sensor, and a photoacoustic spectroscopy sensor; The step S2 specifically includes: step S21', starting the infrared sensor and the auxiliary sensor to detect in real time whether there is R290 refrigerant gas, if the reflective surface is in the non-condensed / frosted state, the infrared sensor outputs the first signal to the controller when detecting the R290 refrigerant gas; if the reflective surface is in the condensed / frosted state, the auxiliary sensor outputs the second signal to the controller when detecting the R290 refrigerant gas; or, the step S2 specifically includes: step S21'', if the reflective surface is in the non-condensed / frosted state, using the infrared sensor The sensor detects in real time whether there is R290 refrigerant gas in its infrared gas chamber, and outputs the first signal to the controller when the R290 refrigerant gas is detected. After the R290 refrigerant gas concentration value detected by the infrared sensor reaches the auxiliary sensor detection accuracy, the auxiliary sensor is started to detect in real time whether there is R290 refrigerant gas, and the detected second signal is output to the controller. If the reflecting surface is in the condensation / frosting state, the auxiliary sensor is used to detect in real time whether there is R290 refrigerant gas, and the second signal is output to the controller when the R290 refrigerant gas is detected.

10. The R290 refrigerant gas leakage detection method according to claim 1, characterized in that: The auxiliary sensor is one of a MOX sensor, an electrochemical sensor, and a thermal catalytic sensor; When the reflecting surface is in the condensation / frosting state, the MOX sensor, the electrochemical sensor or the thermocatalytic sensor is in an on state; when the reflecting surface is in the non-condensation / frosting state, the MOX sensor, the electrochemical sensor or the thermocatalytic sensor is in an off state.

11. An R290 refrigerant gas leakage detection device, characterized in that: The R290 refrigerant gas leakage detection device comprises: The shell is provided with an air inlet for allowing the gas to be tested to enter the shell; An infrared sensor is disposed in the housing, and its infrared air chamber is connected to the air inlet so that the gas to be tested can pass through for detection; an auxiliary sensor, disposed in the housing and connected to the air inlet, for detecting whether R290 refrigerant gas exists in the gas to be tested, wherein the detection principle of the auxiliary sensor is different from that of the infrared sensor, and the auxiliary sensor is not affected by condensation / frosting; and The controller is electrically connected to the infrared sensor and the auxiliary sensor, and is used to obtain the state information of the reflective surface in the infrared air chamber, and receive the first signal of the infrared sensor or the second signal of the auxiliary sensor according to the state information.

12. The R290 refrigerant gas leakage detection device according to claim 11, characterized in that: The controller performs the steps of the R290 refrigerant gas leakage detection method according to any one of claims 1 to 10; The auxiliary sensor is a thermal conductivity sensor, an acoustic resonance ultrasonic sensor, a MOX sensor, an electrochemical sensor or a thermal catalytic sensor; The R290 refrigerant gas leakage detection device further includes a temperature and humidity sensor, which is disposed in the housing and is used to detect the ambient temperature and humidity; The controller is electrically connected to the temperature and humidity sensor; The housing comprises an upper cover and a lower cover, the upper cover and the lower cover are buckled and connected to form a containing cavity, and the air inlet is arranged on the upper cover or the lower cover; The R290 refrigerant gas leakage detection device also includes: a waterproof and breathable membrane, disposed at the air inlet; and At least one electromagnetic shielding cover, disposed in the accommodating cavity, and containing the infrared sensor and / or the auxiliary sensor; The controller is disposed in the accommodating cavity.

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