Liquid delivery abnormality diagnosis method and liquid chromatograph

Abstract

The present invention provides a liquid delivery abnormality diagnosis method and a liquid chromatograph, the liquid delivery abnormality diagnosis method comprising: a sealing step of sealing a plurality of plunger pumps (16A; 16A, 16B) are complementarily linked to perform continuous liquid delivery, and a flow path (3) on the outlet side of the liquid delivery device (2) is sealed; a liquid feeding step of feeding the liquid to the liquid feeding device (2) at a preset diagnostic flow rate after the sealing step, and feeding the liquid to the plurality of plunger pumps (16A; 16A, 16B), each of which performs at least one discharge action; a recording step of recording the plurality of plunger pumps (16A; 16B) during the execution of the liquid delivery step; 16A, 16B) records the time change of the liquid supply pressure during the period in which each of the plurality of nozzles (16A, 16B) performs the discharge operation; and a diagnosis step for diagnosing the flow of the plurality of plunger pumps (16A; 16B) on the basis of the behavior of the delivery pressure recorded in the recording step. 16A, 16B) in the discharge operation of each of the plurality of nozzles (16A, 16B).

Description

Technical Field

[0001] The invention relates to a method for diagnosing abnormal liquid delivery and a liquid chromatograph. Background Art

[0002] In a liquid chromatograph, analysis is performed while a liquid serving as a mobile phase is transported at an ultra-high pressure of several MPa to several hundred MPa. As a liquid delivery device used in such a liquid chromatograph, a device that makes a plurality of plunger pumps complementarily linked is generally used (see Patent Document 1). In each plunger pump, a sealing material (plunger seal) is used to seal the sliding portion of the plunger that reciprocates in one direction in the pump chamber to prevent leakage from the pump chamber under high pressure and ensure the sliding property of the plunger. Furthermore, check valves are provided on the inlet and outlet sides of the pump chamber of each plunger, respectively, to prevent a reduction in the delivery pressure of the liquid during the suction action of each plunger pump and ensure the stability of the delivery of the liquid.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 5-272449 Summary of the invention

[0006] [Problems to be solved by the invention]

[0007] The plunger seal is a consumable part. If the plunger seal is worn, leakage from the pump chamber will occur. Even if the plunger is pressed into the pump chamber at a specified speed, the desired liquid delivery flow rate cannot be obtained. Similarly, the check valve's non-return force is reduced due to dirt, etc., resulting in leakage (backflow), and the desired liquid delivery flow rate cannot be obtained. These phenomena have a significant impact on the analysis results in the liquid chromatograph, resulting in a reduction in the reliability of the analysis. When the amount of leakage at the plunger seal and / or the check valve accounts for a certain proportion of the liquid delivery flow rate, the user can easily notice the leakage in the liquid delivery abnormality of the liquid delivery pump based on experience. On the other hand, when the amount of leakage at the plunger seal and / or the check valve is small relative to the liquid delivery flow rate, it is difficult for the user to notice the liquid delivery abnormality of the liquid delivery device.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to easily identify whether or not there is any abnormality in liquid supply in a liquid supply device.

[0009] [Technical means to solve the problem]

[0010] The method for diagnosing abnormal liquid delivery of the present invention comprises:

[0011] A sealing step of sealing a flow path on the outlet side of a liquid delivery device that causes a plurality of plunger pumps to complementarily work together to deliver liquid continuously;

[0012] a liquid delivery step, after the sealing step, causing the liquid delivery device to deliver liquid at a preset diagnostic flow rate, and causing each of the plurality of plunger pumps to perform at least one discharge action before the liquid delivery pressure of the liquid delivery device reaches a predetermined pressure;

[0013] a recording step of recording the behavior of the liquid supply pressure during the period when each of the plurality of plunger pumps performs the ejection operation in the execution of the liquid supply step; and

[0014] A diagnosing step of diagnosing whether or not there is a liquid supply abnormality in the discharge operation of each of the plurality of plunger pumps based on the behavior of the liquid supply pressure recorded in the recording step.

[0015] The liquid chromatograph of the present invention comprises:

[0016] A liquid delivery device having a plurality of plunger pumps and a pressure sensor, wherein the plurality of plunger pumps are linked to each other complementarily to deliver liquid of a continuous mobile phase, and the pressure sensor detects the delivery pressure;

[0017] an opening and closing mechanism for opening and closing a flow path on an outlet side of the liquid delivery device;

[0018] a controller configured to control the operation of the liquid delivery device and the opening and closing mechanism, and when a diagnostic mode is selected, the opening and closing mechanism closes the flow path on the outlet side of the liquid delivery device, causes the liquid delivery device to deliver liquid at a preset diagnostic flow rate, and causes each of the plurality of plunger pumps to perform at least one ejection operation before the liquid delivery pressure reaches a predetermined pressure; and

[0019] The recording unit records the behavior of the liquid delivery pressure while each of the plurality of plunger pumps performs the discharge operation in the diagnosis mode.

[0020] [Effects of the Invention]

[0021] According to the liquid delivery abnormality diagnosis method of the present invention, the flow path on the outlet side of the liquid delivery device is sealed, the liquid delivery device is caused to deliver liquid at a preset diagnostic flow rate, and each of the plurality of plunger pumps of the liquid delivery device is caused to perform at least one ejection action before the liquid delivery pressure of the liquid delivery device reaches a specified pressure, and the behavior of the liquid delivery pressure during the period when each of the plurality of plunger pumps performs the ejection action is recorded. When there is an abnormality such as leakage at the plunger seal and / or the check valve of any plunger pump of the liquid delivery device, the liquid delivery pressure in the ejection action of the plunger pump is difficult to increase compared with the liquid delivery pressure in the ejection action of the other plunger pumps, and as a result, the liquid delivery pressure of the liquid delivery device will not rise linearly to the specified pressure. Therefore, based on the behavior of the liquid delivery pressure during the period when each of the plurality of plunger pumps performs the ejection action, it is possible to diagnose whether there is a liquid delivery abnormality in the ejection action of each of the plurality of plunger pumps. As a result, the user can easily identify whether there is a liquid delivery abnormality in the liquid delivery device.

[0022] According to the liquid chromatograph of the present invention, the flow path on the outlet side of the liquid delivery device can be opened and closed by an opening and closing mechanism. When the diagnostic mode is selected, the flow path on the outlet side of the liquid delivery device is closed by the opening and closing mechanism, and the liquid delivery device is caused to deliver liquid at a preset diagnostic flow rate. Before the liquid delivery pressure of the liquid delivery device reaches a specified pressure, each of the plurality of plunger pumps of the liquid delivery device performs at least one ejection action. In the diagnostic mode, the behavior of the liquid delivery pressure during the ejection action of each of the plurality of plunger pumps is recorded, so that it is possible to diagnose whether there is a liquid delivery abnormality in the ejection action of each of the plurality of plunger pumps. As a result, the user can easily identify whether there is a liquid delivery abnormality in the liquid delivery device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram showing an embodiment of a liquid chromatograph.

[0024] Figure 2 This is a diagram showing an example of the behavior of the liquid supply pressure in the normal diagnosis mode when there is no leakage in either the liquid supply device or the outlet side of the liquid supply device.

[0025] Figure 3 This is a diagram showing an example of the behavior of the liquid delivery pressure when a leak occurs only in one of the pumps and the diagnosis flow rate is set to L1 in the diagnosis mode.

[0026] Figure 4 This is a diagram showing an example of the behavior of the liquid delivery pressure when a leak occurs only in one of the pumps and the diagnosis flow rate is set to L2 (> L1) in the diagnosis mode.

[0027] Figure 5This is a diagram showing an example of the behavior of the liquid delivery pressure when the diagnosis flow rate is set to L3 in the diagnosis mode when leakage occurs in two pumps.

[0028] Figure 6 This is a diagram showing an example of the behavior of the liquid delivery pressure when the diagnosis flow rate is set to L4 in the diagnosis mode when leakage occurs in two pumps.

[0029] Figure 7 This is a diagram showing an example of the behavior of the liquid delivery pressure when liquid leakage occurs on the outlet side of the pump and the liquid delivery device.

[0030] Figure 8 This is a flowchart showing an example of a procedure for diagnosing abnormality in liquid supply in the above-described embodiment.

[0031] [Explanation of Symbols]

[0032] 1: Liquid Chromatography

[0033] 2: Liquid delivery device

[0034] 3: Analyze the flow path

[0035] 4: Open and close valve

[0036] 6: Automatic Sampler

[0037] 8: Separation column

[0038] 10: Detector

[0039] 12: Controller

[0040] 14: Calculation and processing device

[0041] 16A; 16B: plunger pump

[0042] 18A; 18B: Inlet side check valve

[0043] 20A; 20B: Check valve on the outlet side

[0044] 22: Pressure sensor

[0045] 24: Control Department

[0046] 26: Records Department DETAILED DESCRIPTION

[0047] Hereinafter, an embodiment of a method for diagnosing abnormal liquid delivery and a liquid chromatograph according to the present invention will be described with reference to the accompanying drawings.

[0048] An embodiment of a liquid chromatograph is shown in Figure 1 middle.

[0049] The liquid chromatograph 1 includes a liquid feeding device 2 , an on-off valve 4 (on-off mechanism), an automatic sampler 6 , a separation column 8 , a detector 10 , a controller 12 , and a calculation processing device 14 .

[0050] The liquid delivery device 2 includes: two plunger pumps 16A, 16B; an inlet-side check valve 18A and an inlet-side check valve 18B respectively provided at the inlet side of each plunger pump 16A, 16B; an outlet-side check valve 20A and an outlet-side check valve 20B respectively provided at the outlet side of each plunger pump 16A, 16B; a pressure sensor 22 for detecting the liquid delivery pressure; and a control unit 24 for controlling the operation of the plunger pumps 16A, 16B. The control unit 24 is realized by an electronic circuit equipped with a central processing unit (CPU) (central computing unit) and an information storage device.

[0051] The plunger pump 16A and the plunger pump 16B complement each other so that one plunger pump performs a mobile phase suction operation while the other plunger pump performs a mobile phase discharge operation, thereby stably conveying the mobile phase at a set flow rate.

[0052] In addition, in the embodiment, the pressure sensor 22 is arranged downstream of the outlet side check valve 20A and the outlet side check valve 20B and detects the liquid delivery pressure, but the function of the pressure sensor 22 can also be realized by a pressure sensor arranged in each of the plunger pump 16A and the plunger pump 16B and detecting the pressure in the pump head of each of the plunger pump 16A and the plunger pump 16B.

[0053] The on-off valve 4 is provided on the analysis flow path 3 through which the mobile phase delivered from the outlet of the liquid delivery device 2 flows. In the embodiment, the on-off valve 4 is provided between the liquid delivery device 2 and the automatic sampler 6 on the analysis flow path 3 to open and close the analysis flow path 3. The on-off valve 4 is in an open state during analysis and in a closed state during a diagnostic mode described later, and is used to set the area from the liquid delivery device 2 to the on-off valve 4 as a closed system.

[0054] An automatic sampler 6, a separation column 8, and a detector 10 are provided in order from the upstream side on the analysis flow path 3, downstream of the on-off valve 4. The automatic sampler 6 injects a sample into the mobile phase flowing through the analysis flow path 3. The separation column 8 is used to separate components in the sample injected into the mobile phase by the automatic sampler 6. The detector 10 is used to detect each component separated by the separation column 8.

[0055] The controller 12 is used to control the operation of the liquid delivery device 2, the on-off valve 4, the automatic sampler 6 and the detector 10. The controller 12 can be realized by a system controller dedicated to the liquid chromatograph or a computer in which software dedicated to the liquid chromatograph is introduced.

[0056] The calculation processing device 14 is a computer provided so as to be able to communicate with the controller 12. The calculation processing device 14 receives information input from the user, such as setting of analysis conditions, instructions to start analysis, and selection of an operation mode.

[0057] One of the action modes that can be selected by the user includes a diagnostic mode. The so-called diagnostic mode is a mode for diagnosing whether there is abnormal liquid delivery of the mobile phase and the cause thereof. As the cause of abnormal liquid delivery of the mobile phase, in addition to leakage inside the plunger pump 16A, the plunger pump 16B of the liquid delivery device 2, mixing of bubbles, leakage at the inlet side check valve 18A, the inlet side check valve 18B, the outlet side check valve 20A, and the outlet side check valve 20B, leakage from the liquid delivery device 2 to the opening and closing valve 4 can also be listed.

[0058] As functions related to the diagnostic mode, a recording unit 26 is provided in the control unit 24 of the liquid supply device 2, and a diagnostic unit 28 is provided in the operation processing unit 14. The control unit 24 always knows what operating state each plunger pump 16A and 16B is in (in the ejection operation, suction operation, etc.). The function of the recording unit 26 is to monitor the operating state of the plunger pump 16A and the plunger pump 16B in the diagnostic mode, and to record the behavior of the liquid supply pressure detected by the pressure sensor 22 in the ejection operation of each plunger pump 16A and 16B. The so-called behavior of the liquid supply pressure recorded by the recording unit 26 is the increase amount, time change rate, etc. of the liquid supply pressure in the ejection operation of each plunger pump 16A and the plunger pump 16B. The function of the diagnostic unit 28 is to automatically diagnose the presence or absence of abnormalities related to the liquid supply of the liquid supply device 2 based on the behavior of the liquid supply pressure in the diagnostic mode recorded by the recording unit 26. The functions of the recording unit 26 and the diagnostic unit 28 are obtained by the CPU executing a specific computer program.

[0059] Furthermore, in the above-described embodiment, the recording unit 26 is provided in the control unit 24, and the diagnosis unit 28 is provided in the operation processing device 14, but these functions may be installed in any one of the controller 12, the operation processing device 14, and the control unit 24. When the recording unit 26 is installed in the controller 12 or the operation processing device 14, it is preferred that the control unit 24 can send information on the operating state of the plunger pump 16A and the plunger pump 16B together with the signal value of the pressure sensor 22 to the controller 12, and the recording unit 26 records the behavior of the liquid delivery pressure in the diagnosis mode in correspondence with the operating state of the plunger pump 16A and the plunger pump 16B.

[0060] In addition, the diagnosis unit 28 is not an essential component. The user can diagnose the abnormality of the liquid supply based on the behavior of the liquid supply pressure in the diagnosis mode recorded by the recording unit 26. When the user diagnoses the abnormality of the liquid supply, it is preferable that the operation processing device 14 has a function of displaying the behavior of the liquid supply pressure in the diagnosis mode recorded by the function of the recording unit 26 on a display (not shown) connected in a manner that can communicate with the operation processing device 14, and prompting the user.

[0061] In the diagnostic mode, the upper limit of the hydraulic pressure and the diagnostic flow rate are set to diagnose the abnormality of the hydraulic pressure. The upper limit of the hydraulic pressure and the diagnostic flow rate can be set by the user arbitrarily or selected from the pre-prepared options.

[0062] The upper limit of the hydraulic pressure is preferably set to a pressure at which it is determined that no leakage occurs in the plunger pump 16A, the plunger pump 16B, the inlet check valve 18A, the inlet check valve 18B, the outlet check valve 20A, and the outlet check valve 20B of the liquid feeding device 2. The upper limit of the hydraulic pressure can be set to, for example, the maximum value of the hydraulic pressure that can be achieved in actual analysis.

[0063] It is necessary to make the plunger pump 16A and the plunger pump 16B perform at least one ejection action before the liquid delivery pressure reaches the upper limit value in the diagnostic mode, so that the behavior of the liquid delivery pressure in the ejection action of the plunger pump 16A and the plunger pump 16B can be recorded. It is more preferable to make the plunger pump 16A and the plunger pump 16B perform multiple ejection actions before the liquid delivery pressure reaches the upper limit value. Although it also depends on the size of the liquid delivery flow rate, when the liquid is delivered at a low flow rate such as 100 μL / min in a state where the downstream side of the liquid delivery device 2 is sealed, the number of ejection actions performed by the plunger pump 16A and the plunger pump 16B before the liquid delivery pressure reaches the upper limit value depends on the pump chamber capacity of the plunger pump 16A and the plunger pump 16B (the volume of liquid that can be ejected in one ejection action) and the internal capacity from the liquid delivery device 2 to the sealed portion (the opening and closing valve 4 in this embodiment). Therefore, in order to make the plunger pump 16A and the plunger pump 16B perform multiple ejection operations before the liquid delivery pressure reaches the upper limit value, it is necessary to ensure an internal volume larger than the pump chamber volume of the plunger pump 16A and the plunger pump 16B between the liquid delivery device 2 and the sealed portion. Therefore, in order to ensure a large internal volume between the liquid delivery device 2 and the sealed portion, the on-off valve 4 may be arranged downstream of the automatic sampler 6.

[0064] The diagnosis of the abnormality in liquid delivery is performed based on the time change of the liquid delivery pressure when the analysis flow path 3 is closed by the on-off valve 4 and the liquid delivery device 2 delivers liquid at the diagnostic flow rate. Figure 2As shown, when the liquid feeding device 2 starts feeding the liquid, the liquid feeding pressure rises substantially linearly and reaches the set upper limit value.

[0065] On the other hand, Figures 3 to 7 As shown, when leakage occurs on at least one of the plunger pump 16A side (internal and / or inlet side check valve 18A of plunger pump 16A) and the plunger pump 16B side (internal and / or inlet side check valve 18B of plunger pump 16B), the liquid delivery pressure will hardly rise linearly to the upper limit value as in normal times. For example, when leakage occurs only on one of the plunger pump sides, the rate of increase of the liquid delivery pressure during the ejection action of the plunger pump on the side where the leakage occurs is lower than the rate of increase of the liquid delivery pressure during the ejection action of the plunger pump on the side where the leakage does not occur. In addition, even if leakage occurs on both sides of the two plunger pumps 16A and 16B, since it is almost impossible for exactly the same amount of liquid to leak at exactly the same pressure on both sides, the waveform of the time change of the liquid delivery pressure will not be linear.

[0066] Figure 3 and Figure 4 An example of the behavior of the liquid delivery pressure when a leak occurs on one of the plunger pumps and the diagnostic flow rates are set to L1 and L2 (> L1) respectively is shown. L1 and L2 are in the order of several tens of μL / min.

[0067] like Figure 3 As shown, if the diagnostic flow rate is set to L1, even if the liquid delivery pressure rises to a certain extent, the liquid delivery pressure in the discharge action of the leaking plunger pump will not rise at all. It can be seen that the plunger pump leaks under the pressure that does not rise, and the leakage amount at the plunger pump is greater than the diagnostic flow rate L1.

[0068] On the other hand, Figure 4 As shown, it can be seen that if the diagnostic flow rate is set to L2 which is larger than L1, although the increase in the hydraulic pressure during the discharge action of the plunger pump with leakage is lower than the increase in the hydraulic pressure during the discharge action of the plunger pump without leakage, the hydraulic pressure during the discharge action of the plunger pump with leakage also increases, and the leakage amount at the plunger pump is less than the diagnostic flow rate L2. In this way, different information can be obtained depending on the diagnostic flow rate, so by performing diagnosis at various diagnostic flow rates, detailed information on the abnormality of liquid delivery can also be obtained.

[0069] in addition, Figure 5 and Figure 6 An example of a change in the liquid delivery pressure over time when a leak occurs in the two plunger pumps 16A and 16B and the diagnostic flow rates are set to L3 and L4 (> L3), respectively. L3 and L4 are in the order of several tens of μL / min.

[0070] like Figure 5 As shown in FIG. 1 , when the diagnostic flow rate is set to L3, the liquid delivery pressure hardly rises in any of the ejection actions of the plunger pump 16A and the plunger pump 16B, and the liquid delivery pressure does not reach the set upper limit value. This means that the maximum leakage at the plunger pump 16A and the plunger pump 16B is greater than the diagnostic flow rate L3.

[0071] On the other hand, Figure 6 As shown, if the diagnostic flow rate is set to L4 which is larger than L3, the liquid delivery pressure rises during the discharge operation of the plunger pump with a small leakage, so the liquid delivery pressure reaches the upper limit value. It can be seen that the leakage on one of the plunger pumps is larger than L3 and smaller than L4.

[0072] In addition, if a leak occurs on the outlet side of the liquid delivery device 2 (the outlet side check valve 20A, the outlet side check valve 20B, the on-off valve 4 and / or the piping from the liquid delivery device 2 to the on-off valve 4), Figure 7 As shown, the airtight seal between the liquid delivery device 2 and the on-off valve 4 cannot be maintained, and the pressure of the liquid delivery decreases. In particular, when the plunger pump is stopped, the pressure cannot be maintained and decreases. When the pressure of the liquid delivery decreases in this way, it can be diagnosed that a leak occurs at the outlet side check valve 20A, the outlet side check valve 20B and / or the on-off valve 4, or that the connection part of the pipe from the liquid delivery device 2 to the on-off valve 4 is loose.

[0073] Next, an example of a procedure for diagnosing a liquid delivery abnormality using the diagnosis mode will be described. Figure 1 and Figure 8 The flowchart is described below.

[0074] If the user selects the diagnostic mode, the user sets the upper limit of the hydraulic pressure and the diagnostic flow rate in the processing unit 14 (step 101). If the user sets the upper limit of the hydraulic pressure and the diagnostic flow rate, these information are sent to the controller 12, and the controller 12 closes the analysis flow path 3 through the on-off valve 4 (step 102), and sends a command to the control unit 24 to operate the liquid delivery device 2 so that the liquid is delivered at the diagnostic flow rate (step 103). At this time, the recording unit 26 starts to record the behavior of the liquid delivery pressure detected by the pressure sensor 22.

[0075] The controller 12 monitors the liquid delivery pressure, and stops the liquid delivery by the liquid delivery device 2 when the liquid delivery pressure reaches the set upper limit value (steps 104 to 106). Among them, when the increase rate of the liquid delivery pressure is below a certain value (for example, 0) for a certain period of time (for example, the time when the plunger pump 16A and the plunger pump 16B respectively perform a certain number of ejection actions), the controller 12 determines that the liquid delivery pressure is stagnant (step 104: Yes), and stops the liquid delivery by the liquid delivery device 2 (step 106). The reason is that when leakage occurs on both the plunger pump 16A side and the plunger pump 16B side, when the leakage amount exceeds the diagnostic flow rate, the liquid delivery pressure does not rise but stagnates and cannot reach the set upper limit value.

[0076] After the liquid supply by the liquid supply device 2 is stopped, the recording unit 26 stops recording the liquid supply pressure (step 107). Thereafter, the diagnosis unit 28 diagnoses the liquid supply abnormality based on the behavior of the liquid supply pressure recorded by the recording unit 26, or the behavior of the liquid supply pressure recorded by the recording unit 26 is presented to the user, and the user diagnoses the liquid supply abnormality (step 108).

[0077] Furthermore, in the above-described embodiment, an example in which the liquid-feeding device 2 includes two plunger pumps 16A and 16B is described, but the present invention is not limited thereto, and can be similarly applied when the liquid-feeding device 2 includes three or more plunger pumps. In addition, in the above-described embodiment, an on-off valve 4 for opening and closing the flow path on the outlet side of the liquid-feeding device 2 is provided between the liquid-feeding device 2 and the automatic sampler 6, but an on-off mechanism having the same function as the on-off valve 4 may be provided inside the automatic sampler 6 or downstream of the automatic sampler 6. By providing such an on-off mechanism at a location downstream of the needle seal or the injection valve of the automatic sampler 6, a diagnostic mode can be utilized in the diagnosis of leakage or pressure resistance at the needle seal or the injection valve of the automatic sampler 6.

[0078] The above-described embodiment is merely an example of the implementation of the liquid supply abnormality diagnosis method and liquid chromatograph of the present invention. The implementation of the liquid supply abnormality diagnosis method and liquid chromatograph of the present invention is as follows.

[0079] In one embodiment of the method for diagnosing abnormal liquid delivery of the present invention, the method comprises:

[0080] A sealing step of sealing a flow path on the outlet side of a liquid delivery device that causes a plurality of plunger pumps to complementarily work together to deliver liquid continuously;

[0081] a liquid delivery step, after the sealing step, causing the liquid delivery device to deliver liquid at a preset diagnostic flow rate so that each of the plurality of plunger pumps performs at least one ejection action;

[0082] a recording step of recording a behavior of a liquid delivery pressure of the liquid delivery device during a period in which each of the plurality of plunger pumps performs the ejection operation in the execution of the liquid delivery step; and

[0083] A diagnosing step of diagnosing whether or not there is a liquid supply abnormality in the discharge operation of each of the plurality of plunger pumps based on the behavior of the liquid supply pressure recorded in the recording step.

[0084] In aspect [1] of the one embodiment of the liquid supply abnormality diagnostic method, in the liquid supply step, the liquid supply by the liquid supply device is performed before the liquid supply pressure reaches a preset upper limit value.

[0085] In aspect [2] of the one embodiment of the abnormal liquid supply diagnosis method, a setting step of setting the diagnostic flow rate is included before the liquid supply step. The aspect [2] can be combined with the aspect [1].

[0086] In aspect [3] of the one embodiment of the method for diagnosing abnormal liquid delivery, in the diagnosing step, it is diagnosed that the liquid delivery abnormality exists in the discharge action of the plunger pump having the lowest increase in the liquid delivery pressure in the discharge action among the plurality of plunger pumps. The aspect [3] may be combined with the aspect [1] and / or the aspect [2].

[0087] In aspect [4] of the one embodiment of the method for diagnosing abnormal liquid supply, in the diagnostic step, when there is a drop in the liquid supply pressure, it is diagnosed that liquid leakage has occurred between the liquid supply device and the sealed position on the outlet side of the liquid supply device. The aspect [4] may be combined with the aspect [1], the aspect [2] and / or the aspect [3].

[0088] In form [5] of the one embodiment of the abnormal liquid delivery diagnosis method, in the liquid delivery step, each of the plurality of plunger pumps performs the ejection operation a plurality of times, and in the diagnosis step, for each of the plurality of plunger pumps, the pressure resistance of the plunger pump is diagnosed based on the liquid delivery pressure when the amount of increase in the liquid delivery pressure in the ejection operation is lower than the amount of increase in the liquid delivery pressure in the previous ejection operation. Form [5] may be combined with form [1], form [2], form [3] and / or form [4].

[0089] In one embodiment of the liquid chromatograph of the present invention, it comprises:

[0090] A liquid delivery device having a plurality of plunger pumps and a pressure sensor, wherein the plurality of plunger pumps are linked to each other complementarily to deliver liquid of a continuous mobile phase, and the pressure sensor detects the delivery pressure;

[0091] an opening and closing mechanism for opening and closing the flow path on the outlet side of the liquid delivery device;

[0092] a controller configured to control the operation of the liquid delivery device and the opening and closing mechanism, and when a diagnostic mode is selected, the opening and closing mechanism closes the flow path on the outlet side of the liquid delivery device, causes the liquid delivery device to deliver liquid at a preset diagnostic flow rate, and causes each of the plurality of plunger pumps to perform at least one ejection operation; and

[0093] The recording unit records the behavior of the liquid delivery pressure while each of the plurality of plunger pumps performs the discharge operation in the diagnosis mode.

[0094] In aspect [1] of the one embodiment of the liquid chromatograph, the controller is configured to cause the liquid supply device to supply liquid before the liquid supply pressure reaches a preset upper limit value in the diagnosis mode.

[0095] In aspect [2] of the one embodiment of the liquid chromatograph, the diagnostic flow rate is a flow rate set by a user. The aspect [2] can be combined with the aspect [1].

[0096] In form [3] of the one embodiment of the liquid chromatograph, a diagnostic unit is included, and the diagnostic unit is configured to diagnose whether there is a liquid delivery abnormality in the discharge operation of each of the plurality of plunger pumps based on the behavior of the liquid delivery pressure recorded by the recording unit. The form [3] can be combined with the form [1] and / or the form [2].

[0097] In the aspect [3], the diagnosis unit may be configured to diagnose that a fluid delivery abnormality exists in the discharge operation of the plunger pump having the smallest increase in the fluid delivery pressure in the discharge operation in the diagnosis mode among the plurality of plunger pumps.

[0098] In the aspect [3], the diagnosis unit may be configured to diagnose that a liquid leak has occurred between the liquid supply device and the opening and closing mechanism when there is a drop in the liquid supply pressure in the diagnosis mode.

[0099] In aspect [4] of the one embodiment of the liquid chromatograph, in the diagnosis mode, each of the plurality of plunger pumps performs the ejection operation a plurality of times. Aspect [4] may be combined with aspect [1], aspect [2], and / or aspect [3].

[0100] In the above-mentioned form [4], the above-mentioned diagnostic unit may be configured to diagnose the pressure resistance of the above-mentioned plunger pumps for each of the above-mentioned plurality of plunger pumps based on the above-mentioned liquid delivery pressure when the amount of increase in the above-mentioned liquid delivery pressure in the above-mentioned ejection action is lower than the amount of increase in the above-mentioned liquid delivery pressure in the above-mentioned ejection action last time.

Claims

1. A method for diagnosing abnormal liquid delivery, comprising: A sealing step of sealing a flow path on the outlet side of a liquid delivery device that causes a plurality of plunger pumps to complementarily work together to deliver liquid continuously; a liquid delivery step, after the sealing step, causing the liquid delivery device to deliver liquid at a preset diagnostic flow rate so that each of the plurality of plunger pumps performs at least one ejection action; a recording step of recording a behavior of a liquid delivery pressure of the liquid delivery device during a period in which each of the plurality of plunger pumps performs the ejection action during execution of the liquid delivery step; as well as A diagnosing step of diagnosing whether or not there is a liquid supply abnormality in the discharge operation of each of the plurality of plunger pumps based on the behavior of the liquid supply pressure recorded in the recording step.

2. The method for diagnosing abnormal liquid delivery according to claim 1, wherein: In the liquid supply step, the liquid supply by the liquid supply device is performed before the liquid supply pressure reaches a preset upper limit value. 3 . The method for diagnosing abnormal liquid supply according to claim 1 , comprising a setting step of setting the diagnostic flow rate before the liquid supply step.

4. The method for diagnosing abnormal liquid delivery according to claim 1, wherein: In the diagnosis step, it is diagnosed that a fluid supply abnormality occurs in the discharge operation of a plunger pump having the smallest increase amount of the fluid supply pressure in the discharge operation among the plurality of plunger pumps.

5. The method for diagnosing abnormal liquid delivery according to claim 1, wherein: In the diagnosis step, when there is a drop in the fluid supply pressure, it is diagnosed that a fluid leakage has occurred between the fluid supply device and a sealed position on the outlet side of the fluid supply device.

6. The method for diagnosing abnormal liquid delivery according to claim 1, wherein: In the liquid delivery step, each of the plurality of plunger pumps is caused to perform the ejection action a plurality of times, In the diagnosis step, for each of the plurality of plunger pumps, the withstand pressure of the plunger pump is diagnosed based on the fluid delivery pressure when the amount of increase in the fluid delivery pressure during the discharge operation is lower than the amount of increase in the fluid delivery pressure during the previous discharge operation.

7. A liquid chromatograph comprising: A liquid delivery device having a plurality of plunger pumps and a pressure sensor, wherein the plurality of plunger pumps are linked to each other complementarily to deliver liquid of a continuous mobile phase, and the pressure sensor detects the delivery pressure; an opening and closing mechanism for opening and closing the flow path on the outlet side of the liquid delivery device; a controller configured to control the operation of the liquid delivery device and the opening and closing mechanism, and when the diagnosis mode is selected, the opening and closing mechanism closes the flow path on the outlet side of the liquid delivery device, causes the liquid delivery device to deliver liquid at a preset diagnosis flow rate, and causes each of the plurality of plunger pumps to perform at least one ejection operation; as well as The recording unit records the behavior of the liquid delivery pressure while each of the plurality of plunger pumps performs the discharge operation in the diagnosis mode.

8. The liquid chromatograph according to claim 7, wherein: The controller is configured to cause the liquid supply device to supply liquid before the liquid supply pressure reaches a preset upper limit value in the diagnosis mode.

9. The liquid chromatograph according to claim 7, wherein: The diagnostic flow rate is a flow rate set by a user. 10 . The liquid chromatograph according to claim 7 , comprising a diagnosis unit configured to diagnose whether or not there is a liquid delivery abnormality in the discharge operation of each of the plurality of plunger pumps based on the behavior of the liquid delivery pressure recorded by the recording unit.

11. The liquid chromatograph according to claim 10, wherein: The diagnosis unit is configured to diagnose that a fluid delivery abnormality exists in the discharge operation of a plunger pump having the smallest increase amount of the fluid delivery pressure in the discharge operation in the diagnosis mode among the plurality of plunger pumps.

12. The liquid chromatograph according to claim 10, wherein: The diagnosis unit is configured to diagnose that a fluid leakage has occurred between the fluid supply device and the opening and closing mechanism when there is a drop in the fluid supply pressure in the diagnosis mode.

13. The liquid chromatograph according to claim 8, wherein: In the diagnosis mode, each of the plurality of plunger pumps is caused to perform the discharge operation a plurality of times.

14. The liquid chromatograph according to claim 13, wherein: The diagnosis unit is configured to diagnose the withstand pressure of each of the plurality of plunger pumps based on the fluid delivery pressure when the amount of increase in the fluid delivery pressure during the discharge operation is lower than the amount of increase in the fluid delivery pressure during the previous discharge operation.

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