Method for monitoring vacuum degree of unit on line and air conditioning system

Abstract

The invention provides a method for monitoring the vacuum degree of a unit on line. The method is characterized by comprising the following steps that S01, whether the gas increasing rate of the unit is larger than the critical increasing rate or not is judged; and S02, if the gas increasing rate of the unit is larger than the critical increasing rate, the vacuum state of the unit is abnormal. By measuring the pressure of the air exhaust box, the air exhaust amount of each time of automatic air exhaust and the air increasing rate of the unit in a period of time are calculated, and therefore the vacuum state of the unit is monitored; in addition, by measuring the pH value of the lithium bromide solution, whether the reason of poor vacuum is one or more of unit air leakage, corrosion inhibitor precipitation or excessive corrosion inhibitor consumption can be judged.

Description

Technical Field

[0001] The present application relates to a method for online monitoring of the vacuum degree of a unit and an air conditioning system.

[0002] Background

[0003] During the operation of the absorption lithium bromide unit, the refrigerant (water) of the evaporator evaporates at a low temperature, and the unit needs to maintain a low pressure state. If external gas enters the unit (for example, during sampling operation) or non-condensable gas is generated inside the unit, the pressure on the shell side of the evaporator will increase, the evaporation amount of the refrigerant will decrease, and the performance of the unit will decrease. Lithium bromide solution is highly corrosive to steel in the presence of oxygen, so when air enters the unit, the gas needs to be discharged from the unit as soon as possible, otherwise the corrosion of the unit will be aggravated and the life of the unit will be greatly shortened. Summary of the invention

[0004] According to a first aspect of the present application, a method for online monitoring of the vacuum degree of a unit is provided, characterized by comprising the following steps:

[0005] S01, determining whether the gas increase rate of the unit is greater than the critical increase rate; and

[0006] S02: If the gas increase rate of the unit is greater than the critical increase rate, an abnormal vacuum state of the unit occurs.

[0007] According to the first aspect of the present application, it is characterized in that it also includes the following steps:

[0008] S03, based on step S02, measuring the pH value of the unit solution; and

[0009] S04, if the pH value of the unit solution is within the normal range, it is determined that the cause of the poor vacuum of the unit is air leakage of the unit; if the pH value of the unit solution is not within the normal range, it is determined that the cause of the poor vacuum of the unit includes corrosion inhibitor precipitation and / or excessive consumption of corrosion inhibitor.

[0010] According to the first aspect of the present application, it is characterized in that it also includes the following steps:

[0011] S05, if the pH value of the unit solution is not within the normal range, the unit is operated at partial load for a certain period of time and the protective exhaust device is operated. If the pH value of the unit solution can return to the normal range, it is determined that the cause of the poor vacuum of the unit includes the precipitation of corrosion inhibitor; if the pH value of the unit solution cannot return to the normal range, it is determined that the cause of the poor vacuum of the unit includes excessive consumption of corrosion inhibitor.

[0012] According to the first aspect of the present application, it is characterized in that it also includes the following steps:

[0013] S06: When it is determined that the cause of the poor vacuum of the unit includes excessive consumption of corrosion inhibitor, a prompt is given to replenish the corrosion inhibitor.

[0014] According to the first aspect of the present application, it is characterized in that it also includes the following steps:

[0015] S07, after confirming that the unit is leaking or the corrosion inhibitor is consumed excessively, operate the protective exhaust device and perform manual treatment.

[0016] According to a first aspect of the present application, it is characterized in that:

[0017] Before step S01, the exhaust pressure is measured, and when the exhaust pressure is greater than a first critical pressure, the exhaust device starts to operate; and after the exhaust device has operated for a period of time, if the exhaust pressure is lower than a second critical pressure, the exhaust device stops operating.

[0018] According to the first aspect of the present application, it is characterized in that the gas increase rate of the unit is calculated based on the suction pressure when the suction starts, the suction pressure when the suction stops, and the time from the start of the suction to the stop of the suction.

[0019] According to the first aspect of the present application, it is characterized in that: in step S02, if the gas increase rate of the unit is greater than the critical increase rate within the set time length range, it is determined that the vacuum state of the unit is abnormal.

[0020] According to the second aspect of the present application, an air conditioning system is provided, characterized in that: according to the method of online monitoring of the vacuum degree of the unit described in the first aspect of the present application, it is determined whether the vacuum state of the unit is normal or the cause of the poor vacuum of the unit is determined.

[0021] According to a second aspect of the present application, it is characterized by comprising: a pH value measuring device, a suction pressure sensor and a protective suction device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] These and other features and advantages of the present application may be better understood by reading the following detailed description with reference to the accompanying drawings, in which like reference numerals refer to like parts throughout, wherein:

[0023] Figure 1 A schematic block diagram of components of an air conditioning system having an absorption lithium bromide unit;

[0024] Figure 2A The first part of the control flow chart for online monitoring of the vacuum degree of the unit;

[0025] Figure 2B The second part of the control flow chart for online monitoring of the vacuum degree of the unit;

[0026] Figure 3 A block diagram showing the specific details of the control device. DETAILED DESCRIPTION

[0027] The purpose of the present invention is to provide a method for online monitoring of the vacuum degree of an air-conditioning system, so as to determine whether the air-conditioning system has poor vacuum and to determine the cause of the poor vacuum of the air-conditioning unit, so as to take corresponding solutions to eliminate the poor vacuum state of the air-conditioning system.

[0028] Figure 1 The figure is a schematic block diagram of the components of an air conditioning system having an absorption lithium bromide unit.

[0029] like Figure 1 As shown, the air conditioning system 100 with an absorption lithium bromide unit includes an evaporator 110, an absorber 120, a generator 130 and a condenser 140; wherein the generator 130 is provided with a heat source fluid inlet 182 (the fluid here is a heat source, such as high-temperature steam or hot water), a heat source fluid outlet 184 (the fluid here can be condensed water of high-temperature steam or a fluid with a lower temperature than that at the heat source fluid inlet 182), a generator solution inlet 186, a generator solution outlet 187 and a generator refrigerant vapor outlet 188; the evaporator 110 is provided with a refrigerant water inlet 176, an evaporator refrigerant vapor outlet 178, a cold water inlet 172 and a cold water outlet 174; the absorber 120 is provided with a cooling water inlet 162, an absorber solution inlet 164, an absorber solution outlet 166; the condenser 140 is provided with a refrigerant water outlet 152 and a cooling water outlet 156. A first pipeline 171 is provided between the generator solution outlet 187 and the absorber solution inlet 164, and a first solution pump 170 is provided on the first pipeline 171 for transporting the concentrated solution in the generator 130 to the absorber 120. A second pipeline 173 is provided between the absorber solution outlet 166 and the generator solution inlet 186, and a second solution pump 160 is provided on the second pipeline 173 for transporting the dilute solution in the absorber 120 to the generator 130. A heat exchanger 163 is provided between the first pipeline 171 and the second pipeline 173 for promoting heat exchange between the concentrated solution in the first pipeline 171 and the dilute solution in the second pipeline 173. A third pipeline 175 is provided between the refrigerant water outlet 152 and the refrigerant water inlet 176, and a throttling device 153 is provided on the third pipeline 175 for throttling and reducing the pressure of the refrigerant water flowing out of the condenser 140. The evaporator 110 is also provided with a self-circulating pipeline 177, which can transfer the refrigerant at the bottom of the evaporator 110 to the top of the evaporator 110 to keep the evaporator tube group always covered with refrigerant. The self-circulating pipeline 177 is provided with a refrigerant pump 161 to promote the circulation of refrigerant water inside the evaporator 110.

[0030] The air conditioning system 100 includes a solution circulation route and a refrigerant circulation route.

[0031] The solution circulation route is as follows: the concentrated solution entering the absorber 120 absorbs the refrigerant vapor from the evaporator 110 to become a dilute solution, and the dilute solution flows into the generator 130 after passing through the second solution pump 160. The dilute solution flowing into the generator 130 is heated by the high-temperature steam and concentrated into a concentrated solution, and the concentrated solution is transported to the absorber 120 by the first solution pump 170 to absorb the refrigerant vapor from the evaporator 110, completing the solution circulation.

[0032] The refrigerant circulation route is as follows: the refrigerant vapor generated by the generator 130 enters the condenser 140 and is condensed in the condenser 140. The refrigerant water from the condenser 140 enters the evaporator 110 through the throttling device 153, absorbs heat on the outer wall of the heat exchange tube of the evaporator 110 and evaporates into refrigerant vapor. The refrigerant vapor enters the absorber 120 and is absorbed by the concentrated solution. The solution after absorbing the refrigerant vapor enters the generator 130 through the second solution pump 160 and is heated to generate refrigerant vapor, completing the refrigerant circulation.

[0033] The air conditioning system 100 further includes an evaporator self-circulation route.

[0034] The refrigerant water is pumped from the bottom of the evaporator 110 to the top of the evaporator 110 by the refrigerant pump 161 , thereby accelerating the heat cycle of the refrigerant inside the evaporator 110 .

[0035] The connection between the air conditioning system 100 and the outside includes a heat source route, a cooling water route, and a cold water route.

[0036] The heat source route is: the heat source entering the generator 130 from the heat source fluid inlet 182 heats and concentrates the dilute solution inside the generator, and the heat source releases heat and flows out of the generator 130 from the heat source fluid outlet 184 .

[0037] The cooling water route is as follows: the cooling water entering the absorber 120 from the cooling water inlet 162 cools the solution in the absorber 120 , and the cooling water continues to flow to the condenser 140 , and after cooling the refrigerant vapor in the condenser 140 , flows out from the cooling water outlet 156 of the condenser 140 .

[0038] The cold water route is as follows: the cold water entering the evaporator 110 from the cold water inlet 172 is evaporated by the refrigerant water in the evaporator 110 and absorbs heat, and then the cold water is cooled and flows out of the evaporator 110 from the cold water outlet 174 .

[0039] Continue as Figure 1As shown, the air conditioning system 100 further includes a pH value measuring device 112, which is installed at the bottom of the absorber 120 to measure the pH value of the dilute solution. As understood by those skilled in the art, the pH value measuring device 112 can also be installed at the bottom of the generator 130, on the second pipeline 173 from the absorber 120 to the generator 130, or on the first pipeline 171 from the generator 130 to the absorber 120.

[0040] Continue as Figure 1 As shown, the air conditioning system 100 further includes an air extraction pipeline 195, which includes two air extraction branches, namely, an absorber air extraction branch 193 and a condenser air extraction branch 194, wherein the absorber air extraction port 191 of the absorber air extraction branch 193 is arranged at the upper part of the absorber 120, and the condenser air extraction port 192 of the condenser air extraction branch 194 is arranged above the refrigerant in the condenser 140. The air extraction pipeline 195 further includes an ejector 124, an air extraction box 126, an air extraction device 121 (such as a vacuum pump), a first air extraction valve 122, a second air extraction valve 123 and an air extraction pressure sensor 127, wherein the ejector 124 and the second air extraction valve 123 are arranged in parallel between the air extraction box 126 and the shell side of the unit (absorber 120 and condenser 140) through pipelines, and the air extraction pressure sensor 127 is used to detect the air extraction pressure in the air extraction box 126. When the unit is operating normally, the first air extraction valve 122 and the second air extraction valve 123 are closed, and the air conditioning system 100 can collect the non-condensable gas (for example, air, hydrogen, nitrogen, etc.) on the shell side of the unit to the air extraction box 126 through the ejection device 124. When the pressure in the air extraction box 126 reaches a certain pressure, the first air extraction valve 122 is opened, and the non-condensable gas in the air extraction box 126 is extracted from the unit through the air extraction device 121. When the unit has a poor vacuum, the unit needs to switch to a forced air extraction state, operate the air extraction device 121 and open the first air extraction valve 122 and the second air extraction valve 123, so that the air extraction device 121 can directly and quickly extract air from the unit, so as to facilitate the gas to be discharged from the unit as soon as possible, thereby reducing the corrosion of the gas to the unit. Therefore, the air extraction device 121, the first air extraction valve 122 and the second air extraction valve 123 together constitute a protective air extraction device.

[0041] Continue as Figure 1As shown, the air conditioning system 100 also includes a control device 111, which is communicatively connected with the pH value measuring device 112, the exhaust pressure sensor 127, the exhaust device 121, the first exhaust valve 122 and the second exhaust valve 123 mentioned above, and is used to receive feedback signals from the pH value measuring device 112 and the exhaust pressure sensor 127, and can control the opening and closing of the first exhaust valve 122 and the second exhaust valve 123 according to the feedback signals. The control device 111 is also provided with a timer 113 to calculate the exhaust time. The control device 111 is also provided with a user interaction interface (not shown in the figure), which can receive information input by the user, and can also feedback messages to the user, such as whether there is a poor vacuum or the reason for the poor vacuum, etc., and can send an alarm of unit leakage or excessive consumption of corrosion inhibitor to the user, so as to prompt the user to perform corresponding leak detection operations or manually replenish corrosion inhibitors.

[0042] Figure 2A-2B The control process of online monitoring of the vacuum degree of the unit is shown, where Figure 2A The first part of the control flow chart for online monitoring of the vacuum degree of the unit; Figure 2B The second part of the control flow chart for online monitoring of the vacuum degree of the unit.

[0043] After careful observation, research and analysis by the inventor, the following three reasons may be the causes of poor vacuum in the unit:

[0044] First, air leakage in the unit will cause non-condensable gases, such as air, to enter the unit, but will not affect the pH value of the dilute solution;

[0045] Second, the precipitation of corrosion inhibitor will cause the lithium bromide solution to corrode the internal structural parts of the unit, produce a large amount of hydrogen, and affect the pH value of the dilute solution;

[0046] Third, excessive consumption of corrosion inhibitors will cause the lithium bromide solution to corrode the internal structural parts of the unit, produce a large amount of hydrogen, and affect the pH value of the dilute solution.

[0047] The technical solution of the present application will determine whether there is a poor vacuum in the air-conditioning system through the following process, and determine the cause of the poor vacuum in the air-conditioning unit, so as to take corresponding solutions to eliminate the poor vacuum state of the air-conditioning system.

[0048] like Figure 2A-2B As shown, in step 202 , the control process of online monitoring of the vacuum degree of the unit is started, and then the process goes to step 204 .

[0049] In step 204, the air conditioning system is kept in normal operation, and the first exhaust valve 122 and the second exhaust valve 123 are kept in a closed state. At this time, the timing time T=0, and the air conditioning system 100 can collect the non-condensable gas (for example, air, hydrogen, nitrogen, etc.) on the shell side of the unit into the exhaust box 126 through the ejector device 124.

[0050] After completing the operation of step 204 , the operation proceeds to step 206 .

[0051] In step 206 , the timer 113 starts timing. After the operation of step 206 is completed, the operation goes to step 208 .

[0052] In step 208, the relationship between the suction pressure and the first critical pressure (e.g., 8 kPa) is determined. The unit continues to operate until the suction pressure sensor 127 detects that the pressure in the suction box 126 rises to exceed the first critical pressure (e.g., 8 kPa), and the operation goes to step 210; if the suction pressure sensor 127 detects that the pressure in the suction box 126 does not exceed the above-mentioned first critical pressure, the operation returns to step 204 and the above operation is repeated.

[0053] In step 210, the air extraction device 121 starts to operate, the first air extraction valve 122 is opened, the air extraction pressure sensor 127 records the pressure P1 in the air extraction box 126 when the air extraction starts, and the air extraction device 121 extracts the gas in the air extraction box 126 out of the unit and continues to operate for a period of time. After completing the operation of step 210, the operation goes to step 212.

[0054] In step 212, the relationship between the suction pressure and the second critical pressure (e.g., 8 kPa) is determined. As the suction device 121 extracts the gas in the suction box 126 out of the unit, the pressure in the suction box 126 gradually decreases. When the suction pressure sensor 127 detects that the pressure in the suction box 126 decreases to below the second critical pressure (e.g., 3 kPa), the operation goes to step 214; if the suction pressure sensor 127 detects that the pressure in the suction box 126 is not lower than the above-mentioned second critical pressure, the operation returns to step 210, and the above operation is repeated, and the suction device 121 continues to pump gas.

[0055] In step 214 , the first air extraction valve 122 is closed, the air extraction device 121 stops running, the air extraction pressure sensor 127 records the pressure P2 in the air extraction box 126 when air extraction stops, and the timer 113 records the time T of stopping air extraction. After completing the operation of step 214 , the operation goes to step 216 .

[0056] In step 216, the relationship between the unit gas increase rate and the critical increase rate (eg, 2 mL / min) is determined. The timer 113 of the control device 111 calculates the pumping volume ΔV and the unit gas increase rate f by the following formula:

[0057]

[0058] Among them, ΔV represents the vacuum volume, the unit is mL, P1 represents the pressure in the vacuum box 126 when the vacuum starts, the unit is kPa; P2 represents the pressure in the vacuum box 126 when the vacuum stops, the unit is kPa; V0 represents the volume of the vacuum box 126, which is a determined value when the unit is designed, the unit is L.

[0059]

[0060] Wherein, f represents the gas increase rate of the unit, and the unit is mL / min; T represents the time when the timer 113 records the stopping of gas extraction, and the unit is min.

[0061] If the unit gas increase rate f is greater than the set critical increase rate (for example, 2 mL / min), it is determined that there is an abnormality in the unit vacuum, and the operation goes to step 220 for subsequent detection; if the unit gas increase rate f is not greater than the above-set critical increase rate, indicating that the unit is operating normally, the operation returns to step 218, the timer is reset, and the timing is restarted, and then returns to step 204 to repeat the above operation.

[0062] In step 220, the relationship between the time recorded by the timer and the critical time is determined. The timer 113 of the control device 111 records the elapsed time T. If the time T recorded by the timer is greater than the set time length (e.g., 60 minutes), it means that the gas increase rate f of the unit within the set time length is greater than the critical increase rate, indicating that the vacuum state of the unit is abnormal, and the operation goes to step 222 to further determine the cause of the abnormal vacuum state; if the time T recorded by the timer is not greater than the set time length, the operation returns to step 206, keeps counting, and repeats the above operation.

[0063] In step 222 , the pH measuring device 112 measures the pH value of the dilute solution. After completing the operation of step 222 , the operation proceeds to step 224 .

[0064] In step 224, the pH value of the dilute solution is determined. Normally, the pH value of the lithium bromide solution is between 9 and 10.5. If the pH value of the dilute solution is measured to be between 9 and 10.5, it means that the pH value of the dilute solution is within the normal range, and there is no precipitation of the unit solution corrosion inhibitor or excessive consumption of the corrosion inhibitor. It can be determined that the cause of the poor vacuum of the unit is the unit leakage, and the operation goes to step 226; if the pH value of the dilute solution is not measured to be between 9 and 10.5, it means that the pH value of the dilute solution is not within the normal range, and it can be determined that the cause of the poor vacuum of the unit is the precipitation of the unit solution corrosion inhibitor or excessive consumption of the solution corrosion inhibitor, and further confirmation of the cause of the poor vacuum of the unit is required, and the operation goes to step 230.

[0065] In step 226, a gas leakage alarm of the unit is issued. After the operation of step 226 is completed, the operation goes to step 228.

[0066] In step 228, the unit performs forced air extraction, operates the air extraction device 121 and opens the first air extraction valve 122 and the second air extraction valve 123, so that the air extraction device 121 directly extracts air from the unit quickly, so as to discharge the gas from the unit as soon as possible, reduce the corrosion of the gas to the unit, and thus protect the unit and wait for manual processing. After completing the operation of step 228, the operation goes to step 238.

[0067] In step 230, in order to further determine whether the cause of the poor vacuum of the unit is the precipitation of the corrosion inhibitor in the unit solution, the unit is operated to form a film. Under low load conditions, the precipitated corrosion inhibitor will dissolve back into the solution and react with the internal structural parts to form a protective film. Specifically, the unit is operated at a partial load (e.g., 50% load) for a certain period of time (e.g., 6 hours), the exhaust device 121 is operated and the first exhaust valve 122 and the second exhaust valve 123 are opened, so as to perform forced exhaust. After completing the operation of step 230, the operation goes to step 232.

[0068] In step 232 , the pH measuring device 112 measures the pH value of the dilute solution again. After completing the operation of step 232 , the operation proceeds to step 234 .

[0069] In step 234, the pH value of the dilute solution is determined again. If the pH value of the dilute solution is between 9 and 10.5, it means that through the operation of step 230, the pH of the dilute solution has returned to the normal range, and it can be determined that the cause of the poor vacuum of the unit includes the precipitation of the corrosion inhibitor in the unit solution, and the excessive consumption of the corrosion inhibitor is excluded, and the operation goes to step 240. If the pH value of the dilute solution is still not between 9 and 10.5, it means that it can be determined that the cause of the poor vacuum of the unit includes the excessive consumption of the corrosion inhibitor, and the operation goes to step 236.

[0070] In step 236, an alarm is issued for excessive consumption of the unit's corrosion inhibitor, indicating that the corrosion inhibitor needs to be replenished manually. After completing the operation of step 236, the operation goes to the above step 228.

[0071] In step 238, manual processing is performed. For the case of air leakage in the unit, there are two common processing methods: the first is to shut down the unit, remove the lithium bromide solution and refrigerant inside the unit, fill it with nitrogen at a certain pressure, and then spray soapy water on the unit body to observe whether there are bubbles; the place with bubbles is the leakage point; the second is to shut down the unit, remove the lithium bromide solution and refrigerant inside the unit, vacuum the unit, detect whether the extracted gas contains helium, and then spray helium at various positions of the unit body to observe whether helium is detected; the place where helium is detected is the leakage point. After checking the leakage point, the unit is repaired accordingly. In the case of excessive consumption of corrosion inhibitor, it is necessary to shut down the unit and replenish the corrosion inhibitor manually. After completing the operation of step 238, the operation goes to the above-mentioned step 240.

[0072] In step 240, it is determined whether the shutdown needs to be continued. If the shutdown state needs to be maintained, the operation goes to step 242 to exit the online monitoring of the vacuum degree of the unit; if the shutdown state does not need to be maintained, the operation goes back to step 204 and the determination is repeated.

[0073] In the above step 234, if the pH value of the measured dilute solution is between 9 and 10.5, it cannot be ruled out that the cause of the poor vacuum of the unit includes unit leakage, and the process of steps 204 to 220 can be recirculated to further determine whether the cause of the poor vacuum of the unit includes unit leakage. If the unit gas increase rate f within the set time length range is not greater than the critical increase rate, it can be ruled out that the cause of the poor vacuum of the unit does not include unit leakage. Otherwise, it includes unit leakage and needs to be further repaired through manual processing.

[0074] In the above step 234, if the measured pH value of the dilute solution is not between 9 and 10.5, it cannot be ruled out that the cause of the poor vacuum of the unit includes unit leakage or solution corrosion inhibitor precipitation. After eliminating the factor of excessive consumption of corrosion inhibitor in step 228, the process from step 204 to step 220 can be recirculated to further determine whether the cause of the poor vacuum of the unit includes unit leakage, and the process from step 224 to step 234 can be recirculated to further determine whether the cause of the poor vacuum of the unit includes solution corrosion inhibitor precipitation.

[0075] Figure 3 The block diagram of the control device is a detailed diagram showing the main components of the control device 111. The control device 111 is capable of storing and executing FIG. 2A to FIG. 2B Program, storage and call shown in the control flow FIG. 2A to FIG. 2B Parameters required for the control process.

[0076] like Figure 3 As shown, the control device 111 includes a bus 302, a processor 304, a memory 306, an input interface 308, and an output interface 310. The processor 304, the memory 306, the input interface 308, and the output interface 310 are connected to the bus 302. The processor 304 can read a program (or instruction) from the memory 306 and execute the program (or instruction) to process data; the processor 304 can also write data or a program (or instruction) into the memory 306. The memory 306 can store programs (instructions) or data. By executing the instructions in the memory 306, the processor 304 can control the memory 306, the input interface 308, and the output interface 310.

[0077] In the present application, the memory 306 can store the FIG. 2A to FIG. 2B The program of the process shown in and the operating parameters required to execute the program.

[0078] The input interface 308 is configured to receive data from the sensors or devices described above (such as Figure 1 The processor 304 can detect feedback signals and user input signals, and the data of these parameters are converted into signals recognizable by the processor 304 and stored in the memory 306.

[0079] The processor 304 is configured to input the signal parameters stored in the memory 306 into the program, thereby obtaining the state that each valve should be adjusted, and analyzing whether there is a vacuum abnormality of the unit and the cause of the poor vacuum of the unit. The processor 304 includes the above-mentioned timer 113 for calculating the pumping time.

[0080] The output interface 310 is configured to receive the state of each valve to be adjusted from the processor 304, thereby generating a control signal for opening and closing each valve (including the first air extraction valve 122 and the second air extraction valve 123), and controlling the opening and closing of each valve through the valve control circuit 312. The output interface 310 is also configured to receive the judgment of whether there is a vacuum abnormality of the unit and the analyzed cause of the poor vacuum of the unit from the processor 304, and output it to the user interaction interface through the alarm control circuit 314 to provide feedback to the user and the corresponding operation to be performed.

[0081] The method for online monitoring of the vacuum degree of a unit of the present application and the air conditioning system using the method can at least achieve the following beneficial technical effects:

[0082] First, by measuring the vacuum box pressure, calculating the vacuum volume of each automatic vacuum and the gas increase rate of the unit over a period of time, the vacuum state of the unit is monitored.

[0083] Second, by measuring the pH value of the lithium bromide solution, the present application can determine whether the cause of the poor vacuum is one or more of air leakage in the unit, precipitation of the corrosion inhibitor, or excessive consumption of the corrosion inhibitor.

[0084] Third, only when poor vacuum occurs will the unit switch to forced vacuum state, and the protective vacuum device will keep running to promptly extract the gas in the unit, thereby reducing corrosion to the unit; at the same time, the vacuum device will not stop running simply because the pressure in the vacuum box is reduced, avoiding repeated start and stop of the vacuum device and extending the life of the vacuum device.

[0085] Although the present application has been described in conjunction with the examples of the embodiments summarized above, various alternatives, modifications, changes, improvements and / or substantially equivalent solutions, whether known or currently or foreseeable in the near future, may be apparent to those skilled in the art. In addition, the technical effects and / or technical problems described in this specification are exemplary rather than restrictive; so the disclosure in this specification may be used to solve other technical problems and have other technical effects and / or may solve other technical problems. Therefore, the examples of the embodiments of the present application as stated above are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit or scope of the present application. Therefore, the present application is intended to include all known or earlier developed alternatives, modifications, changes, improvements and / or substantially equivalent solutions.

Claims

1. A method for online monitoring of the vacuum degree of a unit, characterized in that The following steps are involved: S01, determining whether the unit gas increase rate (f) is greater than a critical increase rate; and S02: If the gas increase rate (f) of the unit is greater than the critical increase rate, an abnormal vacuum state of the unit occurs.

2. The method for online monitoring of the vacuum degree of a unit according to claim 1, characterized in that The following steps are also included: S03, based on step S02, measuring the pH value of the unit solution; as well as S04, if the pH value of the unit solution is within the normal range, it is determined that the cause of the poor vacuum of the unit is air leakage of the unit; if the pH value of the unit solution is not within the normal range, it is determined that the cause of the poor vacuum of the unit includes corrosion inhibitor precipitation and / or excessive consumption of corrosion inhibitor.

3. The method for online monitoring of the vacuum degree of a unit according to claim 2, characterized in that The following steps are also included: S05, if the pH value of the unit solution is not within the normal range, the unit is operated at partial load for a certain period of time and the protective exhaust device is operated. If the pH value of the unit solution can return to the normal range, it is determined that the cause of the poor vacuum of the unit includes the precipitation of corrosion inhibitor; if the pH value of the unit solution cannot return to the normal range, it is determined that the cause of the poor vacuum of the unit includes excessive consumption of corrosion inhibitor.

4. The method for online monitoring of the vacuum degree of a unit according to claim 3, characterized in that The following steps are also included: S06: When it is determined that the cause of the poor vacuum of the unit includes excessive consumption of corrosion inhibitor, a prompt is given to replenish the corrosion inhibitor.

5. The method for online monitoring of the vacuum degree of a unit according to claim 2 or 4, characterized in that The following steps are also included: S07, after confirming that the unit is leaking or the corrosion inhibitor is consumed excessively, operate the protective exhaust device and perform manual treatment.

6. The method for online monitoring of the vacuum degree of a unit according to claim 1, characterized in that: Before step S01, the air extraction pressure is measured, and when the air extraction pressure is greater than a first critical pressure, the air extraction device starts to operate; and After the air extraction device operates for a period of time, if the air extraction pressure is lower than a second critical pressure, the air extraction device stops operating.

7. The method for online monitoring of the vacuum degree of a unit according to claim 6, characterized in that: The gas increase rate (f) of the unit is calculated according to the suction pressure when the suction starts, the suction pressure when the suction stops, and the time from the start of the suction to the stop of the suction.

8. The method for online monitoring of the vacuum degree of a unit according to claim 1, characterized in that: In step S02, if the gas increase rate (f) of the unit is greater than the critical increase rate within the set time range, it is determined that the vacuum state of the unit is abnormal.

9. An air conditioning system, characterized in that: According to the method for online monitoring of the vacuum degree of the unit as described in any one of claims 1 to 8, it is judged whether the vacuum state of the unit is normal or the cause of the poor vacuum of the unit is determined.

10. The air conditioning system according to claim 9, characterized in that include: pH measuring device, extraction pressure sensor and protective extraction device.

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