Method for diagnosing liquid supply abnormalities and liquid chromatograph

Abstract

To make it easier to recognize the presence or absence of liquid supply abnormalities in a liquid supply device.SOLUTION: A method includes a sealing step for sealing an outlet side flow path (3) of a liquid supply device (2) that performs continuous liquid supply by operating the plurality of plunger pumps (16A, 16B) in a complementary manner, a liquid supply step for causing the liquid supply device (2) to supply liquid at a predetermined diagnostic flow rate after the sealing step and causing each of the plurality of plunger pumps (16A, 16B) to perform at least one discharge operation, a recording step for recording a change in the liquid supply pressure over time while each of the plurality of plunger pumps (16A, 16B) performs the discharge operation during executing the liquid supply step, and a diagnostic step for diagnosing whether there is a liquid supply abnormality during the discharge operation of each of the plurality of plunger pumps (16A, 16B) on the basis of the behavior of the liquid supply pressure recorded in the recording step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a liquid delivery abnormality diagnosis method and a liquid chromatograph. [Background technology]

[0002] In liquid chromatographs, analysis is performed while pumping a mobile phase liquid under ultra-high pressures of several MPa to several hundred MPa. A typical liquid delivery device used in such liquid chromatographs is one that uses multiple plunger pumps in a complementary manner (see Patent Document 1). In each plunger pump, the sliding part of the plunger that reciprocates in one direction in the pump chamber is sealed with a sealing material (plunger seal) to prevent liquid leakage from the pump chamber under high pressure and ensure the slidability of the plunger. Furthermore, a check valve is provided on the inlet and outlet sides of the pump chamber of each plunger, which prevents a drop in the liquid delivery pressure during the suction operation of each plunger pump and ensures stable liquid delivery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-272449 Summary of the Invention [Problem to be solved by the invention]

[0004] The plunger seal is a consumable item, and when the plunger seal wears out, liquid leakage from the pump chamber occurs, and the desired liquid delivery flow rate cannot be obtained even if the plunger is pushed into the pump chamber at a specified speed. Similarly, the check valve's check force decreases due to dirt or the like, causing leakage (backflow), and the desired liquid delivery flow rate cannot be obtained. These phenomena have a significant effect on the analysis results in liquid chromatographs, leading to a decrease in the reliability of the analysis. When the amount of leakage from 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 from experience when the liquid delivery pump is abnormal. On the other hand, when the amount of leakage from the plunger seal and / or the check valve is small compared to the liquid delivery flow rate, it is difficult for the user to notice the liquid delivery abnormality of the liquid delivery device.

[0005] The present invention has been made in consideration of the above problems, and has an object to make it easier to recognize whether or not there is a liquid delivery abnormality in a liquid delivery device. [Means for solving the problem]

[0006] The method for diagnosing a fluid delivery abnormality according to the present invention comprises the steps of: a sealing step of sealing a flow path on an outlet side of a liquid delivery device that continuously delivers liquid by complementary interlocking a plurality of plunger pumps; a liquid delivery step of causing the liquid delivery device to deliver liquid at a preset diagnostic flow rate after the sealing step, and causing each of the plurality of plunger pumps to perform at least one discharge operation until the liquid delivery pressure of the liquid delivery device reaches a predetermined pressure; a recording step of recording a time change of the liquid delivery pressure while each of the plurality of plunger pumps is performing the discharge operation during the liquid delivery step; and a diagnosing step of diagnosing whether or not there is a liquid-transfer abnormality during the discharge operation of each of the plurality of plunger pumps, based on the behavior of the liquid-transfer pressure recorded in the recording step.

[0007] The liquid chromatograph according to the present invention comprises: a liquid delivery device having a plurality of plunger pumps and a pressure sensor, the plurality of plunger pumps being linked in a complementary manner to continuously deliver a mobile phase, and the liquid delivery pressure being detected by the pressure sensor; an opening / closing mechanism for opening and closing a flow path on an outlet side of the liquid delivery device; a controller configured to control the operation of the liquid delivery device and the opening / closing mechanism, and when a diagnosis mode is selected, to close the flow path on the outlet side of the liquid delivery device by the opening / closing mechanism, to deliver liquid to the liquid delivery device at a preset diagnosis flow rate, and to cause each of the plurality of plunger pumps to perform at least one discharge operation until the liquid delivery pressure reaches a predetermined pressure; and a recorder that records the behavior of the liquid delivery pressure while each of the plurality of plunger pumps is performing the discharge operation during the diagnosis mode. Effect of the Invention

[0008] According to the method for diagnosing a liquid delivery abnormality 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, each of the multiple plunger pumps of the liquid delivery device is caused to perform at least one discharge operation until the liquid delivery pressure of the liquid delivery device reaches a predetermined pressure, and the behavior of the liquid delivery pressure while each of the multiple plunger pumps is performing the discharge operation is recorded. If there is an abnormality such as leakage in the plunger seal and / or check valve of any of the plunger pumps of the liquid delivery device, the liquid delivery pressure during the discharge operation of that plunger pump becomes less likely to increase compared to the discharge operations of the other plunger pumps, and as a result, the liquid delivery pressure of the liquid delivery pressure does not increase linearly to the predetermined pressure. Therefore, the presence or absence of a liquid delivery abnormality during the discharge operation of each of the multiple plunger pumps can be diagnosed based on the behavior of the liquid delivery pressure while each of the multiple plunger pumps is performing the discharge operation. This makes it easier for a user to recognize the presence or absence of a liquid delivery abnormality in the liquid delivery device.

[0009] 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, and when a diagnosis mode is selected, the flow path on the outlet side of the liquid delivery device is closed by the opening and closing mechanism to deliver liquid to the liquid delivery device at a preset diagnosis flow rate, and each of the plunger pumps of the liquid delivery device is caused to perform at least one discharge operation until the liquid delivery pressure of the liquid delivery device reaches a predetermined pressure, and during the diagnosis mode, the behavior of the liquid delivery pressure while each of the plunger pumps is performing the discharge operation is recorded, so that the presence or absence of a liquid delivery abnormality during the discharge operation of each of the plunger pumps can be diagnosed. This makes it easier for a user to recognize the presence or absence of a liquid delivery abnormality in the liquid delivery device. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an embodiment of a liquid chromatograph. [Diagram 2] 13 is a diagram showing an example of the behavior of the liquid delivery pressure during a normal diagnostic mode when there is no leakage from either the liquid delivery device or the outlet side of the liquid delivery device. FIG. [Diagram 3] FIG. 13 is a diagram showing an example of the behavior of the liquid delivery pressure when a leak occurs in only one of the pumps and the diagnostic flow rate is set to L1 in the diagnostic mode. [Figure 4] FIG. 13 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 diagnostic flow rate is set to L2 (>L1) in the diagnostic mode. [Diagram 5] FIG. 13 is a diagram showing an example of the behavior of the liquid delivery pressure when the diagnostic flow rate is set to L3 in the diagnostic mode in a case where leakage occurs in both pumps. [Figure 6] FIG. 13 is a diagram showing an example of the behavior of the liquid delivery pressure when the diagnostic flow rate is set to L4 in the diagnostic mode in a case where leakage occurs in both pumps. [Figure 7] 11 is a diagram showing an example of behavior of liquid delivery pressure when liquid leakage occurs on the outlet side of a pump and a liquid delivery device. FIG. [Figure 8]13 is a flowchart showing an example of a procedure for diagnosing a liquid transfer abnormality in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the liquid delivery abnormality diagnosis method and liquid chromatograph according to the present invention will be described with reference to the drawings.

[0012] An example of a liquid chromatograph is shown in FIG.

[0013] The liquid chromatograph 1 includes a liquid delivery device 2, an on-off valve 4 (on-off mechanism), an autosampler 6, a separation column 8, a detector 10, a controller 12, and a processing device 14.

[0014] The liquid delivery device 2 includes two plunger pumps 16A, 16B, inlet check valves 18A, 18B provided on the inlet sides of the plunger pumps 16A, 16B, respectively, outlet check valves 20A, 20B provided on the outlet sides of the plunger pumps 16A, 16B, respectively, a pressure sensor 22 that detects the liquid delivery pressure, and a control unit 24 that controls the operation of the plunger pumps 16A, 16B. The control unit 24 is realized by an electronic circuit equipped with a CPU (Central Processing Unit), an information storage device, etc.

[0015] The plunger pumps 16A and 16B work in a complementary manner with each other so that one plunger pump performs an inhalation operation of the mobile phase while the other plunger pump performs an ejection operation of the mobile phase, thereby stably delivering the mobile phase at a set flow rate.

[0016] In this embodiment, the pressure sensor 22 is provided downstream of the outlet side check valves 20A, 20B to detect the liquid delivery pressure, but the function of the pressure sensor 22 may be realized by a pressure sensor provided in each of the plunger pumps 16A and 16B to detect the pressure within the pump head of each of the plunger pumps 16A and 16B.

[0017] The on-off valve 4 is provided on the analysis flow path 3 through which the mobile phase flows, delivered from the outlet of the liquid delivery device 2. In this embodiment, the on-off valve 4 is provided at a position on the analysis flow path 3 between the liquid delivery device 2 and the autosampler 6, and opens and closes the analysis flow path 3. The on-off valve 4 is opened during analysis and closed in a diagnostic mode, which will be described later, to make the area from the liquid delivery device 2 to the on-off valve 4 a closed system.

[0018] An autosampler 6, a separation column 8, and a detector 10 are provided downstream of the on-off valve 4 on the analysis flow path 3, in that order from the upstream side. The autosampler 6 injects a sample into the mobile phase flowing through the analysis flow path 3. The separation column 8 is for separating components in the sample injected into the mobile phase by the autosampler 6. The detector 10 is for detecting each component separated by the separation column 8.

[0019] The controller 12 controls the operations of the liquid delivery device 2, the on-off valve 4, the autosampler 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 installed.

[0020] The arithmetic processing device 14 is a computer that is provided so as to be able to communicate with the controller 12. The arithmetic processing device 14 accepts information input from the user, such as setting of analysis conditions, instructions to start analysis, and selection of operation mode.

[0021] One of the operation modes that the user can select is the diagnosis mode. The diagnosis mode is a mode for diagnosing the presence or absence of an abnormality in the liquid delivery of the mobile phase and its cause. Causes of an abnormality in the liquid delivery of the mobile phase include leakage inside each of the plunger pumps 16A and 16B of the liquid delivery device 2, the inclusion of air bubbles, leakage at the inlet side check valves 18A and 18B and the outlet side check valves 20A and 20B, as well as leakage between the liquid delivery device 2 and the opening and closing valve 4.

[0022] As functions related to the diagnostic mode, the control unit 24 of the liquid delivery device 2 is provided with a recording unit 26, and the arithmetic processing device 14 is provided with a diagnosis unit 28. The control unit 24 constantly grasps the operating state (discharge operation, suction operation, etc.) of each of the plunger pumps 16A and 16B. The recording unit 26 has a function of recording the behavior of the liquid delivery pressure detected by the pressure sensor 22 during the discharge operation of each of the plunger pumps 16A and 16B while monitoring the operating state of the plunger pumps 16A and 16B during the diagnostic mode. The behavior of the liquid delivery pressure recorded by the recording unit 26 is the increase amount and time change rate of the liquid delivery pressure during the discharge operation of each of the plunger pumps 16A and 16B. The diagnosis unit 28 has a function of automatically diagnosing the presence or absence of an abnormality regarding the liquid delivery of the liquid delivery device 2 based on the behavior of the liquid delivery pressure during the diagnostic mode recorded by the recording unit 26. The functions of the recording unit 26 and the diagnosis unit 28 are obtained by the CPU executing a specific computer program.

[0023] In this embodiment, the recording unit 26 is provided in the control unit 24, and the diagnosis unit 28 is provided in the arithmetic processing device 14, but these functions may be implemented in any of the controller 12, the arithmetic processing device 14, and the control unit 24. When the recording unit 26 is implemented in the controller 12 or the arithmetic processing device 14, it is preferable that the control unit 24 transmits information on the operating states of the plunger pumps 16A and 16B together with the signal value of the pressure sensor 22 to the controller 12, so that the recording unit 26 can record the behavior of the liquid delivery pressure during the diagnosis mode in association with the operating states of the plunger pumps 16A and 16B.

[0024] Moreover, the diagnosis unit 28 is not an essential component. The user may diagnose a liquid delivery abnormality based on the behavior of the liquid delivery pressure during the diagnosis mode recorded by the recording unit 26. When the user diagnoses the liquid delivery abnormality, it is preferable that the arithmetic processing device 14 has a function of presenting to the user the behavior of the liquid delivery pressure during the diagnosis mode recorded by the function of the recording unit 26 on a display (not shown) connected to the arithmetic processing device 14 so as to be able to communicate with the arithmetic processing device 14.

[0025] In the diagnosis mode, the upper limit of the liquid delivery pressure and the diagnostic flow rate are set to diagnose liquid delivery abnormalities. The upper limit of the liquid delivery pressure and the diagnostic flow rate can be set by the user or selected from options prepared in advance.

[0026] The upper limit of the liquid delivery pressure is preferably set to a pressure at which it is desired to confirm that no liquid leakage occurs in the plunger pumps 16A, 16B, the inlet check valves 18A, 18B, and the outlet check valves 20A, 20B of the liquid delivery device 2. The upper limit of the liquid delivery pressure can be set to, for example, the maximum liquid delivery pressure that can be reached during an actual analysis.

[0027] In order to record the behavior of the liquid delivery pressure during the discharge operation of each of the plunger pumps 16A and 16B, it is necessary to make each of the plunger pumps 16A and 16B perform at least one discharge operation before the liquid delivery pressure during the diagnosis mode reaches the upper limit. More preferably, each of the plunger pumps 16A and 16B is made to perform a plurality of discharge operations before the liquid delivery pressure reaches the upper limit. Although it depends on the magnitude of the liquid delivery flow rate, when liquid is delivered at a low flow rate such as 100 μL / min with the downstream side of the liquid delivery device 2 sealed, how many discharge operations the plunger pumps 16A and 16B perform before the liquid delivery pressure reaches the upper limit depends on the pump chamber capacity of the plunger pumps 16A and 16B (volume of liquid that can be discharged in one discharge operation) and the internal capacity from the liquid delivery device 2 to the sealed part (opening and closing valve 4 in this embodiment). Therefore, in order to make the plunger pumps 16A and 16B perform a large number of discharge operations before the liquid delivery pressure reaches the upper limit, it is necessary to ensure an internal volume between the liquid delivery device 2 and the sealed portion that is larger than the pump chamber volume of the plunger pumps 16A and 16B. Therefore, in order to ensure a large internal volume between the liquid delivery device 2 and the sealed portion, the opening and closing valve 4 may be disposed downstream of the autosampler 6.

[0028] The diagnosis of a liquid delivery abnormality is performed based on the change in liquid delivery pressure over time when the analysis flow path 3 is closed by the on-off valve 4 and the liquid delivery device 2 is made to deliver liquid at a diagnostic flow rate. If there is no liquid delivery abnormality, as shown in Figure 2, when the liquid delivery device 2 starts delivering liquid, the liquid delivery pressure increases almost linearly and reaches the set upper limit.

[0029] On the other hand, as shown in FIG. 3 to FIG. 7, when leakage occurs on at least one of the plunger pump 16A side (inside of the plunger pump 16A and / or the inlet check valve 18A) and the plunger pump 16B side (inside of the plunger pump 16B and / or the inlet check valve 18B), the liquid delivery pressure almost does not rise linearly to the upper limit value as in the normal state. For example, when leakage occurs only on one of the plunger pumps, the rate of increase of the liquid delivery pressure while the plunger pump on the leaking side is performing a discharge operation is lower than the rate of increase of the liquid delivery pressure while the plunger pump on the non-leaking side is performing a discharge operation. In addition, even if leakage occurs on both sides of the two plunger pumps 16A and 16B, it is almost impossible for the same amount of liquid to leak at the same pressure on both sides, so the waveform of the time change of the liquid delivery pressure does not become linear.

[0030] Figures 3 and 4 show 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. L1 and L2 are on the order of several tens of μL / min.

[0031] As shown in Figure 3, when the diagnostic flow rate is set to L1, the liquid delivery pressure during the discharge operation of the plunger pump where the leak is occurring does not increase at all even when the liquid delivery pressure has increased to a certain extent. This shows that the plunger pump is leaking at a pressure where no increase is observed, and furthermore, the amount of leakage from this plunger pump is greater than the diagnostic flow rate L1.

[0032] On the other hand, as shown in Fig. 4, when the diagnostic flow rate is set to L2, which is larger than L1, the increase in the liquid delivery pressure during the discharge operation of a plunger pump with a leak is lower than the increase in the liquid delivery pressure during the discharge operation of a plunger pump without a leak, but the liquid delivery pressure increases during the discharge operation of the plunger pump with a leak, and the amount of leakage in the plunger pump is less than the diagnostic flow rate L2. In this way, since the information that can be obtained differs depending on the diagnostic flow rate, detailed information on the liquid delivery abnormality can be obtained by performing a diagnosis at various diagnostic flow rates.

[0033] 5 and 6 show an example of the change in the liquid delivery pressure over time when the diagnosis flow rates are set to L3 and L4 (>L3) when leakage occurs in both plunger pumps 16A and 16B. L3 and L4 are on the order of several tens of μL / min.

[0034] As shown in Fig. 5, when the diagnostic flow rate is set to L3, the liquid delivery pressure hardly increases during the discharge operation of either of the plunger pumps 16A and 16B, and the liquid delivery pressure does not reach the set upper limit value. This indicates that the maximum leakage amount in either of the plunger pumps 16A and 16B is larger than the diagnostic flow rate L3.

[0035] On the other hand, as shown in Fig. 6, when the diagnostic flow rate is set to L4, which is larger than L3, the liquid delivery pressure increases during the discharge operation of the plunger pump with a small leakage amount, and the liquid delivery pressure reaches the upper limit. This shows that the leakage amount on one of the plunger pumps is larger than L3 and smaller than L4.

[0036] Furthermore, 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), the airtightness between the liquid delivery device 2 and the on-off valve 4 is not maintained as shown in FIG. 7, and a drop in the liquid delivery pressure occurs. In particular, when the plunger pump is stopped, the pressure cannot be maintained and drops. When a drop in the liquid delivery pressure occurs in this way, it can be diagnosed that a leak has occurred in the outlet side check valve 20A, the outlet side check valve 20B, and / or the on-off valve 4, or that a loosening has occurred in the connection of the piping from the liquid delivery device 2 to the on-off valve 4.

[0037] Next, an example of a procedure for diagnosing a liquid transfer abnormality using the diagnosis mode will be described with reference to the flow chart of FIG. 8 together with FIG.

[0038] When the diagnostic mode is selected by the user, the arithmetic processing device 14 allows the user to set an upper limit value of the liquid delivery pressure and a diagnostic flow rate (step 101). When the upper limit value of the liquid delivery pressure and the diagnostic flow rate are set by the user, the information is sent to the controller 12, and the controller 12 closes the analysis flow path 3 by the on-off valve 4 (step 102), and sends a command to the control unit 24 to operate the liquid delivery device 2 to deliver liquid at the diagnostic flow rate (step 103). At this time, the recording unit 26 starts recording the behavior of the liquid delivery pressure detected by the pressure sensor 22.

[0039] The controller 12 monitors the liquid delivery pressure, and when the liquid delivery pressure reaches a set upper limit, the controller 12 stops the liquid delivery by the liquid delivery device 2 (steps 104 to 106). However, when the rate of increase of the liquid delivery pressure remains below a certain value (for example, 0) for a certain period of time (for example, the time during which the plunger pumps 16A and 16B each perform a certain number of discharge operations), the controller 12 determines that the liquid delivery pressure has stagnated (step 104: Yes), and stops the liquid delivery by the liquid delivery device 2 (step 106). This is because, when leakage occurs on both the plunger pump 16A side and the plunger pump 16B side and the amount of leakage exceeds the diagnosis flow rate in both cases, the liquid delivery pressure does not increase and stagnates, and does not reach the set upper limit.

[0040] After the liquid delivery by the liquid delivery device 2 is stopped, the recording unit 26 stops recording the time change of the liquid delivery pressure (step 107). Thereafter, the diagnosing unit 28 diagnoses a liquid delivery abnormality based on the behavior of the liquid delivery pressure recorded by the recording unit 26, or the behavior of the liquid delivery pressure recorded by the recording unit 26 is presented to the user, and the user diagnoses a liquid delivery abnormality (step 108).

[0041] In the above embodiment, the liquid delivery device 2 is provided with two plunger pumps 16A and 16B, but the present invention is not limited to this, and can be similarly applied to the case where the liquid delivery device 2 is provided with three or more plunger pumps. In the above embodiment, the opening and closing valve 4 for opening and closing the flow path on the outlet side of the liquid delivery device 2 is provided between the liquid delivery device 2 and the autosampler 6, but an opening and closing mechanism having the same function as the opening and closing valve 4 can be provided inside the autosampler 6 or downstream of the autosampler 6. By providing such an opening and closing mechanism downstream of the needle seal or injection valve of the autosampler 6, the diagnosis mode can be used to diagnose leakage and pressure resistance at the needle seal or injection valve of the autosampler 6.

[0042] The above-described embodiment is merely one example of the embodiment of the liquid delivery abnormality diagnosis method and liquid chromatograph according to the present invention. The embodiment of the liquid delivery abnormality diagnosis method and liquid chromatograph according to the present invention is as follows.

[0043] In one embodiment of the method for diagnosing a liquid delivery abnormality according to the present invention, a sealing step of sealing a flow path on an outlet side of a liquid delivery device that continuously delivers liquid by complementary interlocking a plurality of plunger pumps; a liquid delivery step of causing the liquid delivery device to deliver liquid at a preset diagnostic flow rate after the sealing step and causing each of the plurality of plunger pumps to perform at least one discharge operation; a recording step of recording a behavior of the liquid delivery pressure of the liquid delivery device while each of the plurality of plunger pumps is performing the discharge operation during the execution of the liquid delivery step; and a diagnosing step of diagnosing whether or not there is a liquid-transfer abnormality during the discharge operation of each of the plurality of plunger pumps, based on the behavior of the liquid-transfer pressure recorded in the recording step.

[0044] In the aspect [1] of the above embodiment of the method for diagnosing a liquid delivery abnormality, in the liquid delivery step, the liquid delivery device delivers liquid until the liquid delivery pressure reaches a preset upper limit value.

[0045] In the above embodiment of the method for diagnosing a flow abnormality, a setting step of setting the diagnostic flow rate is provided before the flow step. This mode [2] can be combined with the above mode [1].

[0046] In the above embodiment of the method for diagnosing a liquid delivery abnormality, in the diagnosis step, a plunger pump having the lowest increase in the liquid delivery pressure during the discharge operation among the plurality of plunger pumps is diagnosed as having a liquid delivery abnormality during the discharge operation. This aspect [3] can be combined with the above aspects [1] and / or [2].

[0047] In the above embodiment of the method for diagnosing a liquid delivery abnormality, in the diagnosis step, when the liquid delivery pressure drops, it is diagnosed that a liquid leak occurs between the liquid delivery device and a sealing position on the outlet side of the liquid delivery device. This mode [4] can be combined with the above modes [1], [2] and / or [3].

[0048] In the above embodiment of the method for diagnosing a liquid delivery abnormality, in the liquid delivery step, each of the plurality of plunger pumps is caused to perform the discharge operation a plurality of times, and in the diagnosis step, for each of the plurality of plunger pumps, a pressure resistance of the plunger pump is diagnosed based on the liquid delivery pressure when the increase in the liquid delivery pressure during the discharge operation becomes lower than the increase in the liquid delivery pressure during the previous discharge operation. This aspect [5] can be combined with the above aspects [1], [2], [3], and / or [4].

[0049] In one embodiment of the liquid chromatograph according to the present invention, a liquid delivery device having a plurality of plunger pumps and a pressure sensor, the plurality of plunger pumps being linked in a complementary manner to deliver a continuous mobile phase and detecting a liquid delivery pressure by the pressure sensor; an opening / closing mechanism for opening and closing a flow path on an outlet side of the liquid delivery device; a controller configured to control the operation of the liquid delivery device and the opening / closing mechanism, and when a diagnosis mode is selected, to close the flow path on the outlet side of the liquid delivery device by the opening / closing mechanism, to deliver liquid to the liquid delivery device at a preset diagnosis flow rate, and to cause each of the plurality of plunger pumps to perform at least one discharge operation; and a recorder configured to record, during the diagnosis mode, the behavior of the liquid delivery pressure while each of the plurality of plunger pumps is performing the discharge operation.

[0050] In an aspect [1] of the above embodiment of the liquid chromatograph, the controller is configured to, in the diagnostic mode, cause the liquid delivery device to deliver liquid until the liquid delivery pressure reaches a preset upper limit value.

[0051] In the aspect [2] of the above embodiment of the liquid chromatograph, the diagnostic flow rate is a flow rate set by a user. This aspect [2] can be combined with the above aspect [1].

[0052] In the above embodiment of the liquid chromatograph, a diagnostic unit is provided that is configured to diagnose the presence or absence of a liquid delivery abnormality during 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. This configuration [3] can be combined with the above configurations [1] and / or [2].

[0053] In the above aspect [3], the diagnosis unit can be configured to diagnose that a fluid delivery abnormality exists during the discharge operation of a plunger pump among the plurality of plunger pumps that has the smallest increase in the fluid delivery pressure during the discharge operation in the diagnosis mode.

[0054] In addition, in the above aspect [3], the diagnostic unit can be configured to diagnose that a liquid leak has occurred between the liquid delivery device and the opening and closing mechanism when there is a drop in the liquid delivery pressure in the diagnostic mode.

[0055] In the above embodiment of the liquid chromatograph, in the diagnosis mode, each of the plunger pumps is caused to perform the discharge operation a plurality of times. This aspect [4] can be combined with the above aspects [1], [2], and / or [3].

[0056] In the above aspect [4], the diagnostic unit can be configured to diagnose the pressure resistance of each of the plurality of plunger pumps based on the liquid delivery pressure when the amount of increase in the liquid delivery pressure during the discharge operation becomes lower than the amount of increase in the liquid delivery pressure during the previous discharge operation. [Explanation of symbols]

[0057] 1 Liquid chromatograph 2. Liquid delivery device 3 Analysis flow path 4 Opening and closing valve 6 Autosampler 8. Separation Column 10. Detector 12 Controller 14 Processing unit 16A;16B Plunger pump 18A;18B Inlet check valve 20A;20B Outlet side check valve 22 Pressure Sensor 24 Recording Section 26 Diagnostic Department

Claims

1. a sealing step of sealing a flow path on an outlet side of a liquid delivery device that continuously delivers liquid by complementary interlocking a plurality of plunger pumps; a liquid delivery step of causing the liquid delivery device to deliver liquid at a preset diagnostic flow rate after the sealing step, and causing each of the plurality of plunger pumps to perform at least one discharge operation; a recording step of recording a behavior of the liquid delivery pressure of the liquid delivery device while each of the plurality of plunger pumps is performing the discharge operation during the execution of the liquid delivery step; and a diagnosing step of diagnosing whether or not there is a liquid delivery abnormality during the discharge operation of each of the plurality of plunger pumps based on the behavior of the liquid delivery pressure recorded in the recording step.

2. 2. The method for diagnosing a liquid delivery abnormality according to claim 1, wherein in the liquid delivery step, the liquid delivery device delivers liquid until the liquid delivery pressure reaches a preset upper limit value.

3. 2. The method for diagnosing a fluid delivery abnormality according to claim 1, further comprising a setting step of setting the diagnostic flow rate before the fluid delivery step.

4. 2. The method for diagnosing a liquid delivery abnormality according to claim 1, wherein the diagnosing step diagnoses a liquid delivery abnormality during the discharge operation of a plunger pump having the smallest increase in the liquid delivery pressure among the plurality of plunger pumps.

5. 2. The method for diagnosing a liquid delivery abnormality according to claim 1, wherein, in the diagnosing step, when there is a drop in the liquid delivery pressure, it is diagnosed that a liquid leak has occurred between the liquid delivery device and a sealing position on the outlet side of the liquid delivery device.

6. In the liquid sending step, each of the plurality of plunger pumps is caused to perform the discharge operation a plurality of times; 2. The method for diagnosing a liquid delivery abnormality according to claim 1, wherein 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 during the discharge operation becomes lower than the amount of increase in the liquid delivery pressure during the previous discharge operation.

7. a liquid delivery device having a plurality of plunger pumps and a pressure sensor, the plurality of plunger pumps being linked in a complementary manner to deliver a continuous mobile phase and detecting a liquid delivery pressure by the pressure sensor; an opening / closing mechanism for opening and closing a flow path on an outlet side of the liquid delivery device; a controller configured to control the operation of the liquid delivery device and the opening / closing mechanism, and when a diagnosis mode is selected, to close the flow path on the outlet side of the liquid delivery device by the opening / closing mechanism, to deliver liquid to the liquid delivery device at a preset diagnosis flow rate, and to cause each of the plurality of plunger pumps to perform at least one discharge operation; a recording unit that records behavior of the liquid delivery pressure while each of the plurality of plunger pumps is performing the discharge operation during the diagnostic mode.

8. The liquid chromatograph according to claim 7 , wherein the controller is configured to cause the liquid delivery device to deliver liquid in the diagnostic mode until the liquid delivery pressure reaches a preset upper limit value.

9. 8. The liquid chromatograph of claim 7, wherein the diagnostic flow rate is a user set flow rate.

10. 8. The liquid chromatograph according to claim 7, further comprising a diagnosis unit configured to diagnose the presence or absence of a liquid delivery abnormality during the ejection operation of each of the plurality of plunger pumps, based on the behavior of the liquid delivery pressure recorded by the recording unit.

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

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

13. 9. The liquid chromatograph according to claim 8, wherein in the diagnostic mode, each of the plurality of plunger pumps is caused to perform the ejection operation a plurality of times.

14. 14. The liquid chromatograph according to claim 13, wherein the diagnosing unit is configured to diagnose, for each of the plurality of plunger pumps, a pressure resistance of the plunger pump based on the liquid delivery pressure when an amount of increase in the liquid delivery pressure during the discharge operation becomes lower than an amount of increase in the liquid delivery pressure during a previous discharge operation.

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