Air conditioner and pump cutoff identification method thereof

Abstract

The invention discloses an air conditioner and a pump cutoff identification method thereof.The pump cutoff identification method comprises the steps that when a refrigerant is static, the pressure value of an outlet of a pump and the pressure value of an inlet of the pump are measured so as to obtain the first pressure difference between the outlet of the pump and the inlet of the pump; after the pump is started, pressure values of the outlet and the inlet of the pump are measured in real time to obtain a second pressure difference between the outlet and the inlet of the pump, and the second pressure difference and the first pressure difference are added to obtain the actual lift of the pump; and determining that the pump is cut off based on the fact that the actual lift of the pump is smaller than the first preset value and lasts for more than first preset duration. According to the technical scheme provided by the invention, the technical problem that the risk of misjudgment can be caused when an existing air conditioner judges whether flow is cut off or not through the front and back pressure difference of a fluorine pump is solved.

Description

Technical Field

[0001] The invention relates to a fluorine pump flow interruption detection technology, and in particular to an air conditioner and a pump flow interruption identification method thereof. Background Art

[0002] The energy efficiency requirements of data centers are getting higher and higher. Inter-row air conditioning needs to improve the utilization of natural cooling sources. The use of fluorine pump natural cooling function can effectively improve the energy efficiency of the unit.

[0003] However, the existing air-conditioning fluorine pump unit uses Freon as the working medium. The refrigerant at the fluorine pump inlet is easily vaporized when subjected to pressure and / or temperature changes, which can cause the fluorine pump to be cut off, resulting in the refrigerant in the air-conditioning system not circulating, insufficient refrigeration capacity and dry running and grinding of the fluorine pump. Summary of the invention

[0004] At present, the inter-row air conditioner with fluorine pump system mainly judges whether the flow is cut off based on the pressure difference before and after the fluorine pump, but there will be the following problems:

[0005] 1. In compressor mode, the pressure at the fluorine pump is relatively high, the measurement range of the low-pressure pressure sensor is not large enough, and the measurement accuracy of the high-pressure pressure sensor is not high enough. If the measurement accuracy of the pressure sensor is not high enough, there is a risk of misjudgment when judging whether the flow is interrupted by the pressure difference before and after the fluorine pump.

[0006] 2. When the inner and outer units are connected by a long pipe, or when the outer unit is at the bottom and the inner unit is at the top and the height difference between the inner and outer units is too large, the lift of the fluorine pump before and after inlet and outlet may be too large when the flow is interrupted, and the interruption of flow cannot be identified.

[0007] The main purpose of the present invention is to provide a method for identifying pump failure of an air conditioner, aiming to solve the technical problem that there is a risk of misjudgment in judging whether a pump failure occurs by using the pressure difference before and after a fluorine pump in existing air conditioners.

[0008] To achieve the above object, the present invention provides a method for identifying pump failure of an air conditioner, which comprises:

[0009] When the refrigerant is stationary, measuring the pressure values ​​of the pump outlet and the pump inlet to obtain a first pressure difference between the pump outlet and the pump inlet;

[0010] After starting the pump, the pressure values ​​of the pump outlet and the pump inlet are measured in real time to obtain a second pressure difference between the pump outlet and the pump inlet, and the second pressure difference is added to the first pressure difference to obtain the actual head of the pump;

[0011] Based on the fact that the actual lift of the pump is less than the first preset value for more than the first preset time period, it is confirmed that the pump is interrupted.

[0012] In an illustrative embodiment, a first pressure sensor and a second pressure sensor are used to measure the pressure values ​​of the inlet and outlet of the pump respectively, and the value range of the first preset value Pset is:

[0013] a1+a2+0.03bar≤Pset≤a1+a2+0.06bar;

[0014] Wherein, a1 is the tolerance value of the first pressure sensor, and a2 is the tolerance value of the second pressure sensor.

[0015] In an illustrative embodiment, when the refrigerant is stationary, measuring the pressure values ​​of the pump outlet and the pump inlet to obtain a first pressure difference between the pump outlet and the pump inlet includes:

[0016] When the refrigerant is stationary, the pressure values ​​at the pump outlet and the pump inlet are measured for a second preset time period, and the first pressure difference is an average value of the pressure difference between the pump outlet and the pump inlet during the second preset time period.

[0017] In an illustrative embodiment, when the refrigerant is stationary, the air conditioner is powered on to trigger the measurement of the pressure values ​​at the pump outlet and the pump inlet.

[0018] In an illustrative embodiment, it also includes:

[0019] After confirming that the pump is out of service, a flow interruption alarm message is sent.

[0020] In an illustrative embodiment, it also includes:

[0021] After starting the pump, measuring a first temperature at an outlet of the pump;

[0022] determining a degree of subcooling of the refrigerant at the outlet of the pump according to the first temperature and the pressure at the outlet of the pump when the first temperature is measured;

[0023] Based on the fact that the degree of supercooling is greater than or equal to the saturation temperature of the refrigerant corresponding to the pressure that can be increased when the pump pumps the refrigerant at a minimum head, it is confirmed that the pump is interrupted.

[0024] In an illustrative embodiment, determining the degree of subcooling of the refrigerant at the outlet of the pump according to the first temperature and the pressure at the outlet of the pump when the first temperature is measured includes:

[0025] Obtaining the saturation temperature of the refrigerant at the pressure according to the pressure at the outlet of the pump when measuring the first temperature;

[0026] The degree of subcooling is obtained by subtracting the saturation temperature from the first temperature.

[0027] In an exemplary embodiment, the real-time measurement of the pressure values ​​at the pump outlet and the pump inlet begins only after a third preset time interval has elapsed after the pump is started; and / or,

[0028] The first temperature at the pump outlet is measured after a third preset time interval has elapsed since the pump was started.

[0029] In an illustrative embodiment, it also includes:

[0030] Based on the fact that the difference between the actual head of a pump within a fourth preset time period before the current moment and the actual head of the pump at the current moment is greater than the second preset value, and the actual head of a pump within a time range from the first time to the second time after the current moment satisfies formula (1), it is confirmed that the pump is disconnected;

[0031] △P <A×△P_t2 (1)

[0032] Wherein, ΔP is the actual head of any pump in the time range, ΔP_t2 is the actual head of the pump in the fourth preset time before the current moment, and the value range of A is 0.4≤A≤0.8.

[0033] In an illustrative embodiment, it also includes:

[0034] Based on the fact that the difference between an actual head of the pump within a fourth preset time period before the current moment and the actual head of the pump at the current moment is greater than the second preset value, and the difference between the maximum value of the actual head of the pump within the time range between the first time and the second time after the current moment and the minimum value of the actual head of the pump is greater than the third preset value.

[0035] In an exemplary embodiment, the second preset value Ps2 has a value range of: 1 bar ≤ Ps2 ≤ 2 bar; and / or,

[0036] The value range of the fourth preset time length t2 is 30s≤t2≤60s; and / or,

[0037] The value range of the first time t3 is 60s≤t3≤80s; and / or,

[0038] The value range of the second time t4 is 100s≤t4≤120s; and / or,

[0039] The value range of the third preset value Ps3 is 1bar≤Ps3≤2bar.

[0040] The present application also proposes an air conditioner, which comprises:

[0041] Condenser;

[0042] Evaporator;

[0043] A pump, connected to the condenser and the evaporator through pipelines, used to drive the refrigerant to circulate between the condenser and the evaporator, and provided with an inlet and an outlet;

[0044] A first pressure sensor, disposed at the inlet;

[0045] A second pressure sensor is disposed at the outlet;

[0046] A temperature sensor is arranged at the outlet;

[0047] The controller is electrically connected to the first pressure sensor, the second pressure sensor and the temperature sensor, and is configured to execute the pump flow interruption identification method as described above.

[0048] In the technical solution of the present invention, the actual head of the pump can be obtained by adding the second pressure difference to the first pressure difference, and the actual head eliminates the influence of the measurement error of the pressure sensor.

[0049] When the actual head of the pump is less than the first preset value for a duration greater than or equal to the first preset time, it can be confirmed that the pump is interrupted.

[0050] When the actual head of the pump is less than the first preset value and the duration is less than the first preset time, it may be caused by the pressure fluctuation of the liquid refrigerant in motion before and after the pump. Setting the condition for judging that the pump has been cut off to the actual head of the pump being above the first preset value can eliminate the erroneous judgment caused by the pressure fluctuation of the liquid refrigerant.

[0051] Furthermore, since the actual lift of the pump obtained by adding the second pressure difference to the first pressure difference can eliminate the influence caused by the measurement error of the pressure sensor, the pump flow interruption identification method can accurately determine whether the pump is flow interrupted. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] 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.

[0053] Figure 1 This is a structural schematic diagram of an air conditioner in an embodiment of the present application;

[0054] Figure 2 A flow chart of a method for identifying pump failure of an air conditioner in an embodiment of the present application;

[0055] Figure 3 It is a pressure curve diagram of the inlet and outlet of the pump in the embodiment of the present application.

[0056] Description of Figure Numbers:

[0057] 1. Pump; 2. Throttling element; 3. Evaporator; 4. Condenser; 5. Liquid storage tank; 6. First pressure sensor; 7. Second pressure sensor; 8. Temperature sensor.

[0058] 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

[0059] 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.

[0060] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) 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.

[0061] In addition, in the present invention, descriptions such as "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 the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0062] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0064] like Figure 1 As shown, Figure 1 The structure of an air conditioner is shown. The air conditioner can be an inter-row air conditioner. The air conditioner includes a pump 1, a throttling element 2, an evaporator 3, a condenser 4 and a liquid storage tank 5. The outlet of the pump 1 is connected to the inlet of the throttling element 2 through a pipeline, the outlet of the throttling element 2 is connected to the inlet of the evaporator 3 through a pipeline, the outlet of the evaporator 3 is connected to the condenser 4 through a pipeline, the condenser 4 is connected to the inlet of the liquid storage tank 5 through a pipeline, and the outlet of the liquid storage tank 5 is connected to the inlet of the pump 1. There is a refrigerant in the pipeline of the refrigeration system, and the refrigerant can be a Freon working medium.

[0065] The pump 1 can be an impeller pump 1, such as a centrifugal pump, an axial flow pump or a mixed flow pump. The pump 1 can also be a volumetric pump, such as a gear pump or a piston pump. When the pump 1 is in operation, it can suck in liquid refrigerant from the inlet, pressurize it and then output it from the outlet. The refrigerant flows through the throttling element 2, the evaporator 3, the condenser 4 and the liquid storage tank 5 in sequence and then flows back into the pump 1. When the outdoor ambient temperature is low, the air in nature is an abundant natural cold source. The refrigerant absorbs the heat of the air in the indoor environment when passing through the evaporator 3, and releases the heat to the air in the outdoor environment when passing through the condenser 4, thereby achieving refrigeration. Compared with the use of compressor refrigeration alone, this refrigeration method has significant energy-saving effects.

[0066] The air conditioner further includes a detection component and a controller. The detection component includes a first pressure sensor 6, a second pressure sensor 7 and a temperature sensor 8. The first pressure sensor 6 is arranged at the inlet of the pump 1, and is used to detect the pressure at the inlet of the pump 1. The second pressure sensor 7 is arranged at the outlet of the pump 1, and is used to detect the pressure at the outlet of the pump 1. The temperature sensor 8 is arranged at the outlet of the pump 1, and is used to detect the refrigerant temperature at the outlet of the pump 1.

[0067] The controller is a logic control unit of the air conditioner, which may be a single chip microcomputer. The controller is electrically connected to the first pressure sensor 6 , the second pressure sensor 7 , the temperature sensor 8 and the pump 1 .

[0068] like Figure 2 As shown, the present application also proposes a pump flow cut-off identification method for an air conditioner, and the pump flow cut-off identification method is implemented based on the air conditioner as described above. The pump flow cut-off identification method comprises the following steps:

[0069] Step S1: When the refrigerant is stationary, the pressure values ​​of the outlet of the pump 1 and the inlet of the pump 1 are measured to obtain a first pressure difference between the outlet of the pump 1 and the inlet of the pump 1, and then the process proceeds to step S2;

[0070] Before the air conditioner performs cooling, the refrigerant is stationary, and the controller drives the first pressure sensor 6 to measure the first pressure at the inlet of the pump 1, and also drives the second pressure sensor 7 to measure the second pressure at the outlet of the pump 1. The first pressure difference may be equal to the difference between the second pressure and the first pressure.

[0071] Under ideal conditions, before the air conditioner starts cooling, the pressures at the outlet of pump 1 and the inlet of pump 1 are balanced, and the pressure difference between the outlet of pump 1 and the inlet of pump 1 is theoretically equal to zero. However, since both the first pressure sensor 6 and the second pressure sensor 7 have errors during measurement, the measurement results of the first pressure sensor 6 and the second pressure sensor 7 are different before the air conditioner starts cooling. Therefore, the first pressure difference between the outlet of pump 1 and the inlet of pump 1 can reflect the measurement errors of the first pressure sensor 6 and the second pressure sensor 7.

[0072] Step S2: After starting the pump 1, the pressure values ​​of the outlet of the pump 1 and the inlet of the pump 1 are measured in real time to obtain a second pressure difference between the outlet of the pump 1 and the inlet of the pump 1, and the second pressure difference is added to the first pressure difference to obtain the actual head of the pump 1, and then the process proceeds to step S3;

[0073] The user can send a pump 1 cooling mode instruction to the air conditioner through a remote controller, an intelligent terminal or a control panel of the air conditioner. The pump 1 cooling mode instruction is used to instruct the pump 1 to operate so as to cool the air conditioner. After receiving the pump 1 cooling mode instruction, the controller drives the pump 1 to start operating. After the pump 1 is started, the pump 1 sucks the refrigerant from its inlet and outputs it from its outlet after pressurization, so that the refrigerant circulates between the condenser 4 and the evaporator 3.

[0074] During the operation of the pump 1, the controller drives the first pressure sensor 6 to measure the third pressure value at the inlet of the pump 1 in real time, and records the first curve of the third pressure value changing with time. At the same time, the controller also drives the second pressure sensor 7 to measure the fourth pressure value at the outlet of the pump 1 in real time, and records the second curve of the fourth pressure value changing with time. The controller can obtain the second pressure difference at the same moment by subtracting the fourth pressure value from the third pressure value at the same moment.

[0075] The controller adds the second pressure difference and the first pressure difference at each moment to obtain the actual head of the pump 1 at each moment. The actual head eliminates the influence of the measurement errors of the first pressure sensor 6 and the second pressure sensor 7.

[0076] Step S3: Determine whether the actual lift of the pump 1 is less than the first preset value for a period of time or longer. If so, proceed to step S4; otherwise, proceed to step S3.

[0077] Step S4: confirm that pump 1 is shut off.

[0078] The first preset value is an empirical value, which is slightly larger than the pressure difference between the outlet of the pump 1 and the inlet of the pump 1 when the pump 1 suddenly stops flowing during operation. The pressure difference can be calibrated in advance, and then the first preset value can be set to be slightly larger than the pressure difference. When the pump 1 is an impeller pump 1, especially a centrifugal pump 1, the pressure difference between the outlet and the inlet of the pump 1 when the pump 1 stops flowing is close to zero. At this time, the first preset value can be set to be slightly larger than zero.

[0079] The first preset time length is an empirical value, which may be 1 to 4 seconds.

[0080] The actual head of pump 1 fluctuates over time, and the controller starts timing each time the actual head of pump 1 is less than a first preset value, and stops timing when the actual head of pump 1 is greater than or equal to the first preset value. When the timing duration reaches longer than the first preset duration, it is confirmed that the duration that the actual head of pump 1 is less than the first preset value is greater than or equal to the first preset duration.

[0081] When the actual lift of the pump 1 is less than the first preset value for a duration greater than or equal to the first preset time, the controller confirms that the pump 1 is interrupted.

[0082] When the actual head of the pump 1 is less than the first preset value for a duration less than the first preset time, it may be caused by the pressure fluctuation of the liquid refrigerant in the moving state before and after the pump 1. Setting the condition for judging that the pump 1 is disconnected to the actual head of the pump 1 being above the first preset value can eliminate the misjudgment caused by the pressure fluctuation of the liquid refrigerant. Since the actual head of the pump 1 obtained by adding the second pressure difference to the first pressure difference can eliminate the influence caused by the measurement error of the first pressure sensor 6 and the second pressure sensor 7, the pump disconnection identification method can accurately judge whether the pump 1 is disconnected.

[0083] In an illustrative embodiment, the first pressure sensor 6 and the second pressure sensor 7 are used to measure the pressure values ​​of the inlet and outlet of the pump 1 respectively, and the value range of the first preset value Pset is:

[0084] a1+a2+0.03bar≤Pset≤a1+a2+0.06bar

[0085] Wherein, a1 is the tolerance value of the first pressure sensor 6 , and a2 is the tolerance value of the second pressure sensor 7 .

[0086] The tolerance value is the maximum allowable deviation between the output value of the sensor and the measured true value. The tolerance value of the first pressure sensor 6 is the maximum allowable error of the first pressure sensor 6, and the tolerance value of the second pressure sensor 7 is the maximum allowable error of the second pressure sensor 7. When setting the first preset value, the tolerance value of the first pressure sensor 6 and the tolerance value of the second pressure sensor 7 are taken into consideration, which can improve the accuracy of judging whether the pump 1 is interrupted according to the first preset value.

[0087] In an illustrative embodiment, step S1 specifically includes: when the refrigerant is stationary, measuring the pressure values ​​at the outlet of pump 1 and the inlet of pump 1 for a second preset time period, calculating the average value of the pressure difference between the outlet of pump 1 and the inlet of pump 1 within the second preset time period, and taking the average value as the first pressure difference.

[0088] The second preset time period may be 5 to 10 seconds. By calculating the average value of the pressure difference between the outlet and the inlet of the pump 1 within the second preset time period and using the average value as the first pressure difference, the measurement error between the first temperature sensor 8 and the second temperature sensor 8 can be more accurately reflected.

[0089] In an illustrative embodiment, in step S1 , the air conditioner is powered on to trigger the measurement of pressure values ​​at the outlet and the inlet of the pump 1 to obtain a first pressure difference between the outlet and the inlet of the pump 1 .

[0090] Each time the air conditioner is powered on, the controller automatically drives the first pressure sensor 6 and the second pressure sensor 7 to measure the first pressure at the inlet of the pump 1 and the second pressure at the outlet of the pump 1 respectively.

[0091] Every time the air conditioner is just powered on, the refrigerant in the air conditioner is usually in a static state, which can ensure that the refrigerant is static when measuring the pressure values ​​of the outlet and inlet of pump 1. At the same time, the air conditioner automatically measures when it is just powered on, and there is no need to temporarily measure and calculate the first pressure difference after the user issues a cooling mode instruction for pump 1, which can reduce the waiting time of the user. In particular, the measurement errors of the first temperature sensor 8 and the second temperature sensor 8 are automatically calibrated every time the air conditioner is powered on, which can improve the accuracy of subsequent judgment of whether pump 1 is disconnected.

[0092] In an illustrative embodiment, the pump flow interruption identification method further includes step S5, step S6 and step S7;

[0093] Step S5: After starting the pump 1, measure the first temperature of the outlet of the pump 1, and proceed to step S6;

[0094] The controller also drives the temperature sensor 8 to measure a first temperature at the outlet of the pump 1 .

[0095] Step S6: Determine the degree of subcooling of the refrigerant at the outlet of the pump 1 according to the first temperature and the pressure at the outlet of the pump 1 when the first temperature is measured, and proceed to step S7;

[0096] Since in step S2 , the second pressure sensor 7 also measures the second pressure at the outlet of the pump 1 in real time, the controller can obtain the second pressure at the same time when driving the temperature sensor 8 to measure the first temperature at the outlet of the pump 1 .

[0097] The pressure rise process of pump 1 is simplified as an isothermal pressure rise process. The corresponding relationship between the pressure and saturation temperature of the refrigerant can be obtained by looking up the table. The controller can obtain the saturation temperature of the refrigerant at the second pressure according to the second pressure at the outlet of pump 1 when measuring the first temperature. The controller can obtain the supercooling degree of the refrigerant at the outlet of pump 1 by subtracting the saturation temperature of the refrigerant at the second pressure from the first temperature.

[0098] Step S7: Determine whether the degree of supercooling of the refrigerant at the outlet of pump 1 is greater than or equal to the saturation temperature of the refrigerant corresponding to the pressure that can be increased when pump 1 pumps the refrigerant at the minimum head. If so, proceed to step S4, otherwise proceed to step S5.

[0099] The minimum head of pump 1 is predetermined by the performance of pump 1 itself and the performance index of the air conditioner when designing the air conditioner, and is a known value. The pressure that pump 1 can increase when pumping the refrigerant at the minimum head is an empirical value and can be calibrated in advance. Since the corresponding relationship between the pressure and saturation temperature of the refrigerant can be obtained by looking up the table. Therefore, the controller can query the saturation temperature of the refrigerant corresponding to the pressure based on the pressure that pump 1 can increase when pumping the refrigerant at the minimum head. When the controller determines that the supercooling of the refrigerant at the outlet of pump 1 is greater than or equal to the saturation temperature, it confirms that pump 1 is disconnected.

[0100] By comparing the subcooling degree of the refrigerant at the outlet of pump 1 with the saturation temperature of the refrigerant corresponding to the pressure that can be increased when pump 1 pumps the refrigerant at the minimum head, it is determined whether pump 1 is interrupted, making the judgment of pump 1 interruption more accurate and comprehensive.

[0101] In an illustrative embodiment, in step S2, real-time measurement of the pressure values ​​at the outlet and the inlet of pump 1 is started only after a third preset time interval has passed after pump 1 is started; and / or, in step S5, measurement of the first temperature at the outlet of pump 1 is started only after a third preset time interval has passed after pump 1 is started.

[0102] The third preset time length may be 1 to 3 minutes.

[0103] After pump 1 is started for the third preset time, the refrigeration system of the air conditioner runs smoothly and the pressure in the refrigeration system tends to be stable. Only then do the pressure values ​​at the outlet and inlet of pump 1 start to be measured, as well as the first temperature at the outlet of pump 1. This can make the subsequent judgment of whether pump 1 is cut off more accurate.

[0104] In an illustrative embodiment, Figure 3 As shown, the pump flow interruption identification method further includes steps S8 to S10 after step S2;

[0105] Step S8: Determine whether there is a pump 1 within the fourth preset time t2 before the current time t0 whose actual lift difference with the pump 1 at the current time is greater than the second preset value Ps2, if so, proceed to step S9, otherwise proceed to step S8;

[0106] The value range of the second preset value Ps2 is: 1 bar ≤ Ps2 ≤ 2 bar. The value range of the fourth preset time t2 is 30 s ≤ t2 ≤ 60 s.

[0107] Step S9: Determine whether there is an actual lift ΔP of the pump 1 that satisfies the following formula within the time range Δt between the first time t3 and the second time t4 after the current time t0:

[0108] △P <A×△P_t2;

[0109] If yes, go to step S4, otherwise go to step S10;

[0110] Among them, △P is the actual head of any pump 1 in the time range Δt between the first time t3 and the second time t4, △P_t2 is the actual head of the pump 1 in the fourth preset time t2 before the current time t0, A is the adjustment coefficient, and the value range of A is 0.4≤A≤0.8.

[0111] The second time t4 is longer than the first time t3. The value range of the first time t3 is 60s≤t3≤80s. The value range of the second time t4 is 100s≤t4≤120s.

[0112] When there is an actual head △P that satisfies the above inequality in the time range Δt between the first time t3 and the second time t4, it is considered that the actual head drop rate of pump 1 is too fast, and the controller confirms that pump 1 is disconnected. In this way, by monitoring the drop rate of the actual head of pump 1 to determine whether pump 1 is disconnected, it can avoid the situation where the disconnection cannot be identified due to the long pipe connection between the inner and outer units, or the outer unit is at the bottom and the inner unit is at the top and the height difference between the inner and outer units is too large. Therefore, it is more accurate and comprehensive to use this method to confirm whether pump 1 is disconnected.

[0113] Step S10: Determine whether the difference between the maximum actual lift of pump 1 and the minimum actual lift of pump 1 within the time range Δt between the first time t3 and the second time t4 after the current time t0 is greater than the third preset value Ps3. If so, proceed to step S4, otherwise proceed to step S8.

[0114] The value range of the third preset value Ps3 is 1bar≤Ps3≤2bar.

[0115] When the difference between the maximum value of the actual head of pump 1 within the time range Δt and the minimum value of the actual head of pump 1 is greater than the third preset value Ps3, it is considered that the actual head drop rate of pump 1 is too fast, and the controller confirms that pump 1 is disconnected. In this way, by monitoring the drop rate of the actual head of pump 1 to determine whether pump 1 is disconnected, it is possible to avoid the situation where the disconnection cannot be identified due to the long piping connection between the inner and outer units, or the outer unit is at the bottom and the inner unit is at the top and the height difference between the inner and outer units is too large. Therefore, it is more accurate and comprehensive to use this method to confirm whether pump 1 is disconnected.

[0116] In an illustrative embodiment, the air conditioner further comprises an alarm module. The alarm module can be used to send out a flow interruption alarm message. The alarm module can be a photoacoustic alarm, a speaker, a display screen, an alarm light or a communication module. The alarm module is electrically connected to the controller.

[0117] Step S4 also includes sending a flow interruption alarm message after confirming that the pump 1 has a flow interruption.

[0118] After confirming that the pump 1 has sent a flow cut-off, the controller sends a flow cut-off alarm message to the user or the operation and maintenance personnel through the alarm device. The flow cut-off alarm message can be sent out in the form of graphic information or photoacoustic information.

[0119] 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 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 identifying pump failure of an air conditioner, characterized in that: include: When the refrigerant is stationary, measuring the pressure values ​​of the pump outlet and the pump inlet to obtain a first pressure difference between the pump outlet and the pump inlet; After starting the pump, the pressure values ​​of the pump outlet and the pump inlet are measured in real time to obtain a second pressure difference between the pump outlet and the pump inlet, and the second pressure difference is added to the first pressure difference to obtain the actual head of the pump; Based on the fact that the actual lift of the pump is less than the first preset value and lasts for more than the first preset time period, it is confirmed that the pump is interrupted.

2. The pump flow interruption identification method according to claim 1, characterized in that: The first pressure sensor and the second pressure sensor are used to measure the pressure values ​​at the inlet and outlet of the pump respectively. The value range of the first preset value Pset is: a1+a2+0.03bar≤Pset≤a1+a2+0.06bar; Wherein, a1 is the tolerance value of the first pressure sensor, and a2 is the tolerance value of the second pressure sensor.

3. The pump interruption identification method according to claim 1, characterized in that: The step of measuring the pressure values ​​of the pump outlet and the pump inlet to obtain a first pressure difference between the pump outlet and the pump inlet comprises: The pressure values ​​of the pump outlet and the pump inlet are measured for a second preset time period, and the average value of the pressure difference between the pump outlet and the pump inlet within the second preset time period is determined as the first pressure difference.

4. The pump flow interruption identification method according to claim 1, characterized in that: When the refrigerant is stationary, the air conditioner is powered on to trigger the measurement of the pressure values ​​at the pump outlet and the pump inlet.

5. The pump flow interruption identification method according to claim 1, characterized in that: Also includes: After confirming that the pump is out of service, a flow interruption alarm message is sent.

6. The pump flow interruption identification method according to any one of claims 1 to 5, characterized in that: Also includes: After starting the pump, measuring a first temperature at an outlet of the pump; determining a degree of subcooling of the refrigerant at the outlet of the pump according to the first temperature and the pressure at the outlet of the pump when the first temperature is measured; Based on the fact that the degree of supercooling is greater than or equal to the saturation temperature of the refrigerant corresponding to the pressure that can be increased when the pump pumps the refrigerant at a minimum head, it is confirmed that the pump is interrupted.

7. The pump flow interruption identification method according to claim 6, characterized in that: The step of determining the degree of subcooling of the refrigerant at the outlet of the pump according to the first temperature and the pressure at the outlet of the pump when the first temperature is measured includes: Obtaining the saturation temperature of the refrigerant at the pressure according to the pressure at the outlet of the pump when measuring the first temperature; The degree of subcooling is obtained by subtracting the saturation temperature from the first temperature.

8. The pump flow interruption identification method according to claim 6, characterized in that: After the pump is started, the real-time measurement of the pressure values ​​at the pump outlet and the pump inlet begins after a third preset time interval; and / or, The first temperature is measured after a third preset time interval has elapsed after the pump is started.

9. The pump flow interruption identification method according to any one of claims 1 to 5, characterized in that: Also includes: Based on the fact that the difference between the actual head of a pump within a fourth preset time period before the current moment and the actual head of the pump at the current moment is greater than the second preset value, and the actual head of a pump within a time range from the first time to the second time after the current moment satisfies formula (1), it is confirmed that the pump is disconnected; △P <A×△P_t2 (1) Wherein, ΔP is the actual head of any pump in the time range, ΔP_t2 is the actual head of the pump in the fourth preset time before the current moment, and the value range of A is 0.4≤A≤0.

8.

10. The pump flow interruption identification method according to any one of claims 1 to 5, characterized in that: Also includes: Based on the fact that the difference between an actual head of the pump within a fourth preset time period before the current moment and the actual head of the pump at the current moment is greater than the second preset value, and the difference between the maximum value of the actual head of the pump within the time range from the first time to the second time after the current moment and the minimum value of the actual head of the pump is greater than the third preset value, it is confirmed that the pump has been cut off.

11. An air conditioner, characterized in that: include: Condenser; Evaporator; A pump, connected to the condenser and the evaporator through pipelines, used to drive the refrigerant to circulate between the condenser and the evaporator, and provided with an inlet and an outlet; A first pressure sensor, disposed at the inlet; A second pressure sensor is disposed at the outlet; as well as A controller is electrically connected to the first pressure sensor, the second pressure sensor and the temperature sensor, and is configured to execute the pump flow interruption identification method according to any one of claims 1 to 10.

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