JP2006118374A - Liquid feeding system - Google Patents

Abstract

The present invention provides a liquid chromatograph pump capable of accurately delivering a liquid over a wide flow range with a single pump.
A liquid chromatograph pump has a first pump 100 and a second pump 200 for feeding an eluent, and both the first and second pumps are arranged in a first direction in the direction of feeding the eluent. The first pump is on the upstream side and the second pump is on the downstream side, and are combined so that they can cooperate with each other. Then, the flow path switching means 5 is provided, and the flow path of the eluent is switched by the flow path switching means so that one of a plurality of operation modes having different cooperative states of both pumps can be selected. By selecting the operation mode, the liquid can be fed by switching to one of a plurality of liquid feeding amount modes having different liquid feeding flow rate ranges.
[Selection] Figure 1

Description

  The present invention relates to a liquid feeding system, and more particularly to a liquid feeding system suitable for a liquid chromatograph system that requires liquid feeding in a wide flow rate range.

  For example, a plunger pump having two plungers is known for a liquid feeding system (a liquid chromatograph pump system system) incorporated in a liquid chromatograph system. In such a plunger pump, two plungers are independently driven by a motor, and pulsation of the flow rate is reduced by cooperative driving of both plungers. For example, in the example described in Patent Document 1, the second plunger also reciprocates once while the first plunger reciprocates once, and the flow rate pulsation generated by the suction operation of the first plunger is corrected by the operation of the second plunger. That is, the first plunger determines the flow rate, and the second plunger is used for correcting the pulsation of the first plunger.

  Normally, when operating a liquid chromatograph pump system system, first, an eluent (a liquid to be fed in the liquid chromatograph system) is filled in a pump or pipe, and bubbles are discharged. When the preparatory work is thus completed, the pump discharge pressure is then allowed to reach a predetermined target value, and then the operation is switched to the steady operation. And if it transfers to a steady operation, the analysis and measurement in a liquid chromatograph system will be started.

JP-A 63-173866

  In a liquid chromatograph pump system, for example, nanoliter (nl) per minute flow rate (abbreviated as “nanoliter level flow rate”) to microliter (μl) per minute flow rate (“microliter level flow rate”). In many cases, liquid feeding in a wide flow rate range is required. Conventionally, in order to meet the liquid supply requirement in such a wide flow rate range, it has been necessary to change the type of pump according to the liquid supply flow rate. In other words, in the conventional liquid chromatograph pump system, the ratio of the minimum flow rate to the maximum flow rate is only about 100 times, and when the required flow rate range is wider than that, multiple types with different flow rate ranges are prepared. However, it was necessary to selectively use them. For this reason, the conventional liquid chromatograph pump system requires a lot of labor and time to change the flow rate range.

  The present invention has been made in the background as described above. For example, it is possible to provide a liquid feeding system that can accurately perform liquid feeding in a wide flow range from a nanoliter level to a microliter level. It is aimed.

  For the above purpose, in the present invention, in the liquid feeding system in which the first pump and the second pump that pressurize and feed the liquid are combined so that they can cooperate with each other, the flow path switching means is provided, By switching the flow path of the liquid by the flow path switching means, it is possible to select any one of a plurality of operation modes having different cooperative states of the first and second pumps, According to the selection of the operation mode, the liquid feeding can be performed by switching to any one of a plurality of liquid feeding amount modes having different liquid feeding flow rate ranges.

  Further, in the present invention, with respect to the liquid feeding system as described above, a liquid feeding amount mode in which only one of the first and second pumps is used for liquid feeding during steady operation in which liquid feeding is performed while maintaining a predetermined pressure and flow rate, A liquid supply amount mode in which the first and second pumps are used for liquid supply during the steady operation is included in the plurality of liquid supply amount modes.

  Further, in the present invention, for the liquid feeding system as described above, the flow rate used as a reference for switching between the plurality of liquid feeding amount modes is determined based on the analysis time or measurement time required in the liquid feeding target system and the discharge flow rate. Like to do.

  Further, in the present invention, in the liquid feeding system as described above, the flow path switching means has a plurality of ports, and is formed by an active valve that switches the flow paths by switching the connection of the plurality of ports. ing.

  Further, in the present invention, in the liquid feeding system as described above, the range of the liquid feeding flow rate over the plurality of liquid feeding amount modes is 1 nanoliter / min to 200 microliter / min.

  Further, in the present invention, for the above purpose, the first and second pumps for feeding and feeding the eluent under pressure are provided, and both the first and second pumps feed the eluent. The first pump is on the upstream side and the second pump is on the downstream side, and is configured to be combined so that they can cooperate with each other. In the system, a flow path switching unit is provided, and the flow path of the eluent is switched by the flow path switching unit, so that each of the first and second pumps in a plurality of operation modes having different cooperative states. One of them can be selected, and by selecting the operation mode, it is possible to switch to one of a plurality of liquid feeding amount modes having different liquid feeding flow rate ranges and perform liquid feeding. Features and To have.

  In the present invention, by switching the flow path of the eluent by the flow path switching means, it becomes possible to select different operation modes in the cooperative state of both pumps. Switching is possible. For this reason, for example, liquid feeding in a wide flow range from an extremely low flow rate of a nanoliter level to a low flow rate of a microliter level can be accurately performed with one liquid feeding system. As a result, it is possible to change the flow rate range in a short time, which can contribute to increasing the processing efficiency in, for example, a liquid chromatograph system.

  Hereinafter, preferred embodiments for carrying out the present invention will be described. FIG. 1 and FIG. 2 show a configuration example of a liquid chromatograph system to which a liquid chromatograph pump system that is a liquid delivery system according to the first embodiment is applied. The liquid chromatograph system of this example includes a liquid chromatograph pump system (abbreviated as a pump device) PS, an injector 53, a column 54, a detector 55, and a storage tank 56. The pump device PS sends the eluent to the column 54 at a predetermined pressure in a flow rate range of 1 nanoliter / min to 200 microliter / min as a particularly preferable flow rate range. The injector 53 injects a sample to be analyzed and mixes it with the eluent. The eluent mixed with the sample is introduced into the column 54. In the column 54, a plurality of component substances contained in the sample are separated from each other as the eluent of the sample mixture moves. The separated component substances are detected by the detector 55, and thereby component analysis and measurement are performed. The used eluent is collected in the storage tank 56. The column 54 is filled with fine silica gel particles and the like, and a load pressure of, for example, about 10 MPa is generated in the pump device PS due to fluid resistance when flowing through the column 54. The magnitude of the load pressure varies depending on the diameter of the column and the passing flow rate.

  The pump device PS is a liquid feeding system according to the first embodiment of the present invention, and includes a pump unit P, a controller 50, a storage tank 51, a deaeration device (degasser) 14, a suction pipe 15, an active valve 5, and a suction pipe 16. , An intermediate discharge pipe 17, an intermediate suction pipe 18, and a discharge pipe 19.

  The pump part P is formed by combining a first plunger pump (first pump) 100 and a second plunger pump (second pump) 200 in an integrated structure in series. In addition to the plungers 101 and 201, the first and second pressurizing chambers 102 and 202 are provided. The pressurizing chambers 102 and 202 are more liquid-tight than the seals 124 and 224, respectively. In this embodiment, both plungers 101 and 201 have the same diameter. The first and second plungers 101 and 201 are respectively connected to linear motion actuators 122 and 222 driven by motors 121 and 221 and are slidably held by bearings 123 and 223, respectively. The rotations of the motors 121 and 221 are converted into linear motions by the linear actuators 122 and 222, respectively, and the first and second plungers 101 and 201 perform linear motion in response thereto. The first pressurizing chamber 102 is connected to a suction passage 103 for the first pressurizing chamber connected to the suction pipe 16 and a discharge passage 104 for the first pressurizing chamber connected to the intermediate discharge pipe 17. On the other hand, the second pressurizing chamber 202 is connected to a suction passage 203 for the second pressurizing chamber connected to the intermediate suction pipe 18 and a discharge passage 204 for the second pressurizing chamber connected to the discharge pipe 19. . Pressure sensors 60 and 61 are provided in the discharge passages 104 and 204, respectively.

  The controller 50 controls the operation of the active valve 5 and the pump part P. That is, the controller 50 performs drive control of the motors 121 and 221 based on signals from the pressure sensors 60 and 61 and performs opening / closing control of the active valve 5. The storage tank 51 stores the eluent sent by the pump unit P. The degassing device 14 degass the eluent. The suction pipe 15 connects the storage tank 51 and the active valve 5, and causes the elution liquid to be sucked into the active valve 5 from the storage tank 51 in accordance with the liquid feeding operation of the pump unit P.

  The active valve 5 is a rotary valve that opens and closes by switching the flow path by a driving source not shown in the figure, and in the example shown in the figure, there are six ports 5a, 5b, 5c, 5d, 5e, and 5f and each of these ports. A plurality of flow paths (port connection flow paths) for selective connection, two flow paths 5h and 5g in the illustrated example. The volumes of the flow paths 5h and 5g are very small. The first to third ports 5a, 5b, and 5c are an eluent suction system for the first plunger pump 100 of the pump part P, the first port 5a is connected to the suction pipe 15, and the second port 5b is Connected to the suction pipe 16, the third port 5 c is a stopper that is not connected to any pipe. On the other hand, the fourth to sixth ports 5d, 5e, and 5f are discharge systems for the eluent pressurized by the first plunger pump 100 of the pump section P, and the fourth port 5d is connected to the intermediate suction pipe 18. The fifth port 5e is connected to the intermediate discharge pipe 17, and the sixth port 5f is a stopper that is not connected to any pipe. FIG. 1 shows a state in which the first and second ports 5a and 5b are connected by the flow path 5g and the fourth and fifth ports 5d and 5e are not connected. On the other hand, FIG. 2 shows a state in which the fourth and fifth ports 5d and 5e are connected by the flow path 5h, and the first and second ports 5a and 5b are not connected. Such an active valve 5 functions as a flow path switching means for switching the flow path of the eluent in the pump device PS in order to switch the liquid feeding amount mode as described later.

  The suction pipe 16 connects the active valve 5 and the pump part P, and causes the pump part P to suck the eluent sucked into the active valve 5 from the storage tank 51. The intermediate discharge pipe 17 sends the eluent discharged from the pump part P to the active valve 5. The intermediate suction pipe 18 sucks the eluent discharged from the pump part P and passed through the active valve 5 into the pump part P again. The discharge pipe 19 sends the eluent discharged from the pump part P to the injector 53. The discharge pipe 19 is provided with a drain valve 9.

  Below, the outline of the liquid feeding path | route in the liquid chromatograph system of this example is demonstrated. In the state of FIG. 1, that is, in the state where both the first and second ports 5 a and 5 b are connected by the flow path 5 g, the storage tank 51 is led to the first port 5 a of the active valve 5 through the suction pipe 15. The eluent is guided to the first pressurizing chamber 102 via the first passage 5g, the second port 5b, and the suction pipe 16 and the suction passage 103 for the first pressurizing chamber.

  On the other hand, in the state of FIG. 2, that is, in the state where both the fourth and fifth ports 5 d and 5 e are connected by the second flow path 5 h, the discharge is performed from the first pump 100 through the discharge passage 104 and the intermediate discharge pipe 17. The eluent guided to the fifth port 5e of the active valve 5 is then guided to the suction passage 203 of the pump part P via the second flow path 5h, the fourth port 5d and the intermediate suction pipe 18. The eluent guided to the suction passage 203 is further guided to the injector 53 via the second pressurizing chamber 202, the discharge passage 204, and the discharge pipe 19. The analysis sample is mixed with the eluent guided to the injector 53 by the injector 53 and the component analysis of the analysis sample is performed. At this time, a load pressure of about 10 MPa is generated in the pump part P of the pump device PS. It is as follows.

  Below, operation | movement in pump apparatus PS is demonstrated. The pump device PS is configured to perform liquid feeding in a plurality of liquid feeding amount modes each having a different flow rate range. Each liquid supply mode is switched by changing the operation coordination state of both the first and second pumps 100 and 200 by switching the eluent flow path by the active valve 5. First, the operation in the first liquid supply amount mode in which the eluent is supplied at an extremely low flow rate of nanoliter level will be described. FIG. 3 shows an operation mode of the pump device PS in the first liquid supply mode. 3A is an opening / closing operation of the drain valve 9, FIG. 3B is an opening / closing operation of the active valve 5 with respect to the first plunger 101, FIG. 3C is a displacement of the first plunger 101, and FIG. 3D is an active valve 5 with respect to the second plunger 201. 3E is the displacement of the second plunger 201, FIG. 3F is the flow rate of the first pump 100 (first pump flow rate), FIG. 3G is the flow rate of the second pump 200 (second pump flow rate), FIG. 3H indicates the discharge pressure of the pump device PS detected by the pressure sensor 61. The horizontal axis in the figure is time.

  In the following description, as in the example of FIG. 1, in the active valve 5, both the first and second ports 5a and 5b are connected by the flow path 5g, and both the fourth and fifth ports 5d and 5e are not connected. The state of connection is referred to as “open” for the first plunger 101 and “closed” for the second plunger 201. At this time, the first pressurizing chamber 102 is connected to the storage tank 51 via the active valve 5, and the first pressurizing chamber 102 and the second pressurizing chamber 202 are in a disconnected state. On the other hand, as shown in FIG. 2, both the fourth and fifth ports 5d and 5e are connected by the flow path 5h, and both the first and second ports 5a and 5b are not connected. Is called “closed”, and the second plunger 201 is called “open”. At this time, the first pressurization chamber 102 and the storage tank 51 are blocked by the active valve 5, while the first pressurization chamber 102 is connected to the second pressurization chamber 202 via the active valve 5. As described above, when the active valve 5 is “open” with respect to the first plunger 101, the active valve 5 is “closed” with respect to the second plunger 201, and when the active valve 5 is “closed” with respect to the first plunger 101. 2 The plunger 201 is “open”.

  Further, the first and second plungers 101 and 201 are in a state where they are retracted by the linear actuators 122 and 222, that is, in FIGS. 1 and 2, the plunger is located at the left end of the pressurizing chamber. The state is called the bottom dead center, and when it is pushed by the linear actuators 122 and 222, that is, the state located at the right end of the pressurizing chamber in FIGS. 1 and 2 is called the top dead center. I will decide.

  In the case of a nanoliter flow rate, the pump device PS is appropriately prepared for the bubble discharge / eluent filling (bubble discharge / eluent filling operation) before starting the analysis, and the discharge pressure of the pump device PS is appropriate at the start of liquid feeding. Usually, the operation is performed in the order of a start-up operation (start-up operation operation) which is an operation for raising the pressure to a certain pressure in a short time and a steady operation (steady operation operation) in which liquid feeding is performed while maintaining a predetermined pressure and flow rate. In these, the operation cooperative states of the first and second pumps 100 and 200 are different. That is, in bubble discharge / eluent filling, liquid is fed in an operation mode in which both the first and second pumps 100 and 200 are used, and in start-up operation, liquid is fed in an operation mode in which only the first pump 100 is used. In the steady operation when performing low-flow liquid feeding, liquid feeding is performed in an operation mode in which only the second pump 200 is used.

  First, bubble discharge / eluent filling will be described. In bubble discharge / eluent filling, an eluent passage (pressurizing chamber, piping, flow path, etc.) in the liquid chromatograph system is filled with the eluent while discharging bubbles therefrom. As shown in FIG. 3A, the drain valve 9 is opened. Comparing FIG. 3B and FIG. 3D, the opening / closing operation of the active valve 5 with respect to the second plunger 201 is delayed by a half cycle with respect to the opening / closing operation with respect to the first plunger 101.

  Comparing FIG. 3C and FIG. 3E, the reciprocating motion of the second plunger 201 is delayed by a half cycle with respect to the reciprocating motion of the first plunger 101. When the first plunger 101 is pulled and moves from the top dead center to the bottom dead center, the second plunger 201 is pushed in and moves from the bottom dead center to the top dead center. That is, in the suction process of the first pump 100, the second pump 200 is a discharge process. Conversely, when the first plunger 101 is pushed in and moves from the bottom dead center to the top dead center, the second plunger 201 is pulled in and moves from the top dead center to the bottom dead center. That is, in the discharge process of the first pump 100, the second pump 200 is a suction process.

  Comparing FIG. 3F and FIG. 3G, when the first pump 100 is in the suction process, the second pump 200 is in the discharge process. Conversely, when the first pump is in the discharge process, the second pump is in the suction process. Here, the reason why the first pump flow rate is larger than the second pump flow rate is that the moving speed of the first plunger is larger than the moving speed of the second plunger.

  Comparing FIG. 3B to FIG. 3E, the operations of the first and second plungers 101 and 102 are delayed by a quarter cycle with respect to the opening / closing operation of the active valve 5. Accordingly, the opening / closing operation of the active valve 5 in FIG. 3B with respect to the first plunger 101, the reciprocation of the first plunger 101 in FIG. 3C, the opening / closing operation of the active valve 5 in FIG. 3D with respect to the second plunger 2, and the second plunger in FIG. Each of the two reciprocating motions is sequentially delayed by a quarter period.

  For example, as shown in FIG. 3B, the active valve 5 changes from “closed” to “open” with respect to the first plunger 101. Next, as shown in FIG. 3C, the first plunger 101 changes from the top dead center to the bottom dead center, and the suction process of the first pump 100 is performed with a delay of a quarter cycle. Next, the active valve 5 changes from “closed” to “open” with respect to the second plunger 2 as shown in FIG. Next, as shown in FIG. 3E, the second plunger 2 is changed from the top dead center to the bottom dead center, and the suction process of the second pump 200 is performed with a delay of a quarter cycle.

  As shown in FIG. 3B, the active valve 5 changes from “open” to “closed” with a half cycle delay with respect to the first plunger 101. Next, as shown in FIG. 3C, the position of the first plunger 101 changes from the bottom dead center to the top dead center, and the discharge process of the first pump 100 is performed with a delay of a quarter cycle. Next, as shown in FIG. 3D, the active valve 5 changes from “open” to “closed” with respect to the second plunger 2 and is further delayed by a quarter cycle, as shown in FIG. 3D. As shown to 3E, the 2nd plunger 2 changes from a bottom dead center to a top dead center, and the discharge process of the 2nd pump 200 is performed. As shown in FIG. 3H, the discharge pressure of the pump includes a minute fluctuation component of the first pump flow rate and the second pump flow rate, but is substantially constant.

  In bubble discharge and eluent filling, as shown in FIG. 3, the first and second plungers are reciprocated a plurality of times. From the drain valve 9, the difference between the first pump flow rate and the second pump flow rate is discharged, and at the same time, the bubbles are also removed. In particular, in this example, it is possible to easily discharge bubbles accumulated in the second pressurizing chamber 202 on the downstream side. As a result, liquid preparation prior to analysis and measurement can be completed in a short time.

  When the bubble discharge / eluent filling is completed, the first and second plungers and the active valve are arranged at the home positions described below, and the operation proceeds to the starting operation. As described above, the start-up operation is an operation mode in which the discharge pressure of the pump device PS is increased to an appropriate pressure in a short time at the start of liquid feeding. By performing this, the time required to reach the target pressure, that is, the pump device The rise time at the start-up of the PS can be shortened. Prior to the start of the start-up operation, the first and second plungers and the active valve are arranged at the home position. In the home position, the active valve 5 is “open” with respect to the first plunger 101 and “closed” with respect to the second plunger 201. The first and second plungers are arranged at the bottom dead center. Therefore, both the first and second pressure chambers are filled with the eluent.

  In the following description, when the active valve 5 is “open” with respect to the first plunger 101, it is simply described that the active valve 5 is “open”. Therefore, the active valve 5 being “open” means “open” with respect to the first plunger 101 and “closed” with respect to the second plunger 201 as shown in FIG. In addition, when the active valve 5 is “closed” with respect to the first plunger 101, it is simply described that the active valve 5 is “closed”. Therefore, the fact that the active valve 5 is “closed” means that the first plunger 101 is “closed” and the second plunger 201 is “open” as shown in FIG. .

  When in the home position, the active valve 5 is “open”. First, the drain valve 9 is closed as shown in FIG. 3A, and the active valve 5 is changed from “open” to “closed” as shown in FIGS. 3B and 3D. Therefore, as shown in FIG. 2, the first pressurizing chamber 102 is connected to the second pressurizing chamber 202 via the active valve 5. As shown in FIG. 3C, the first plunger 101 is moved from the bottom dead center toward the top dead center at a predetermined speed, and the discharge process of the first pump is performed. As can be seen from the gradient of the graph, the moving speed of the first plunger 101 in the start-up operation is smaller than that in the case of bubble discharge and eluent filling. As shown in FIG. 3E, since the second plunger 201 is disposed at the bottom dead center, the eluent discharged from the first pressurizing chamber 102 is guided to the second pressurizing chamber 202 via the active valve 5. From there, it is discharged to the discharge pipe 19. At this time, the second pump 200 is not substantially operated. That is, the second pump 200 merely functions as a passage for the eluent in the pressurizing chamber 202. Therefore, as shown in FIG. 3F, the first pump flow rate is a predetermined value corresponding to the moving speed of the first plunger 101, but as shown in FIG. 3G, the second pump flow rate is zero.

  When the discharge pressure of the pump part P, that is, the discharge pressure in the discharge pipe 19, reaches a value (Pset−ΔPset) lower than the target pressure Pset by the operation in the starting operation as described above, as shown in FIG. Switch to.

  Next, the steady operation when the eluent is fed at an extremely low flow rate at the nanoliter level will be described. When the steady operation is started, as shown in FIGS. 3B and 3D, the active valve 5 is changed from “closed” to “open”. Therefore, as shown in FIG. 1, the second pressurizing chamber 202 is cut off from the first pressurizing chamber 102. As shown in FIG. 3C, the first plunger 101 stops at a predetermined position between the bottom dead center and the top dead center. Therefore, as shown in FIG. 3F, the first pump flow rate is zero. On the other hand, the second pump flow rate becomes the target flow rate Qset as shown in FIG. 3G. As shown in FIG. 3H, the discharge pressure of the pump increases and reaches the target pressure Pset. The target pressure Pset is determined by the diameter of the column 54 and the flow rate required there. When the discharge pressure of the pump reaches the target pressure Pset, the pressure sensor 61 notifies the controller 50 of that. The controller 50 transmits a command for steady operation to the first and second pumps 100 and 200 and the active valve 5. In steady operation, liquid delivery is performed at a constant liquid delivery flow rate while maintaining the discharge pressure at the target pressure Pset. As described above, in this example, in steady operation at a nanoliter level flow rate, only the second plunger 201 is pushed at a constant low speed to maintain the discharge pressure at the target pressure Pset and the liquid feed flow rate to nanoliter. The target flow rate Qset is maintained.

  When the analysis and measurement operations that require liquid feeding at such an ultra-low flow rate are completed, the first and second plungers 101 and 201 and the active valve 5 return to the home position described above, and the next analysis or measurement is performed. Wait for the operation.

  Here, in the example of FIGS. 1 and 2, the first plunger diameter and the second plunger diameter are configured to be the same diameter, but the first plunger diameter may be larger than the second plunger diameter. Good.

  Hereinafter, the operation of the pump device PS when the pump device PS sends the eluent at a low flow rate of the microliter level will be described. Liquid feeding at a microliter level flow rate includes a second liquid feeding amount mode and a third liquid feeding amount mode, each having a different flow rate range.

  First, the second liquid feeding amount mode will be described. FIG. 4 is a diagram illustrating a “closed-closed” state appearing on the active valve 5 in the second liquid feeding amount mode. “Closed-closed” is a state in which the first port 5a and the second port 5b are isolated, and the fourth port 5d and the fifth port 5e are also isolated. When the active valve 5 is in the “closed-closed” state, the active valve 5 is isolated from both the first pressurizing chamber 102 and the second pressurizing chamber 202.

  FIG. 5 shows an operation mode of the pump device PS in the second liquid feeding amount mode. A to G in FIG. 5 correspond to A to G in FIG. 3, and H in FIG. 5 indicates the flow rate of the eluent discharged from the pump device. Even in the case of a microliter level flow rate, the steady operation is started after the bubble discharge / eluent filling and start-up operation, but the operation of bubble discharge / eluent filling is the same as in FIG. In the case of a microliter level flow rate, the start-up operation is not always necessary and can be omitted. In this example, the start-up operation is omitted, and when the bubble discharge / eluent filling is completed, the operation is shifted to the steady operation.

  When the bubble discharge / eluent filling is completed, the first and second plungers and the active valve are arranged at the home position. In the home position, the active valve 5 is “open” with respect to the first plunger 101 and “closed” with respect to the second plunger 201. That is, the “active valve 5” defined above is in an “open” state, the first plunger is disposed at the bottom dead center, and the second plunger is disposed at an intermediate position between the top dead center and the bottom dead center. Accordingly, the first and second pressure chambers are filled with the eluent.

  First, as shown in FIG. 5A, the drain valve 9 is closed, and in the phase of Phase 1 in the first cycle, the active valve 5 is changed from “open” to “closed-closed” as shown in FIGS. 5B and 5D. " Therefore, as shown in FIG. 4, the active valve 5 is in a state of being blocked from both the first pressurizing chamber 102 and the second pressurizing chamber 202. As shown in FIG. 5E, the second plunger 201 is moved from the intermediate position toward the top dead center at a predetermined speed, and the discharge process of the second pump 200 is performed. As shown in FIG. 5C, since the first plunger 101 is disposed at the bottom dead center, the first pump is not substantially operated. Therefore, as shown in FIG. 5G, the second pump flow rate is a predetermined value corresponding to the moving speed of the second plunger 201, but as shown in FIG. 5F, the first pump flow rate is zero.

  In the Phase 2-1 stroke in the first cycle, as shown in FIGS. 5B and 5D, the active valve 5 is in a “closed-closed” state. As shown in FIG. 5E, the second plunger 201 moves at a predetermined speed in the direction of the top dead center, and the discharge process of the second pump is subsequently performed. As shown in FIG. 5C, the first plunger 101 moves from the bottom dead center to the top dead center at a predetermined speed, and the pressure in the first pressurizing chamber 102 is the pressure in the second pressurizing chamber 202 (pump discharge). Pressurize until pressure is reached. Therefore, as shown in FIG. 5G, the second pump flow rate is a predetermined value corresponding to the moving speed of the second plunger 201, but as shown in FIG. 5F, the first pump flow rate is zero.

  In the Phase 2-2 stroke in the first cycle, as shown in FIGS. 5B and 5D, the active valve 5 is changed from “closed-closed” to “closed”. Therefore, as shown in FIG. 2, the first pressurizing chamber 102 is connected to the second pressurizing chamber 202 via the active valve 5. As shown in FIG. 5E, the second plunger 201 moves to the top dead center at half the speed of Phase 1 and Phase 2-1, and the discharge process of the second pump is completed. As shown in FIG. 5C, the first plunger 101 moves in the top dead center direction at the same speed as the second plunger 201, and the discharge process of the first pump is performed. Therefore, as shown in FIG. 5G, the second pump flow rate is half the flow rate of Phase 1 or Phase 2-1, but as shown in FIG. 5F, the first pump flow rate is the same as the second pump flow rate. That is, the total flow rate is obtained by discharging half of the target flow rate by the first pump and the second pump.

  In the Phase 3 stroke in the first cycle, as shown in FIGS. 5B and 5D, the active valve 5 is kept in the “closed” state. As shown in FIG. 5E, the second plunger 201 moves from the top dead center to the intermediate position, and the suction process of the second pump is performed. As shown in FIG. 5C, the first plunger 101 moves to the top dead center at twice the speed of the second plunger 201 at Phase 1, and the discharge process of the first pump is completed. Therefore, the second pump flow rate is a negative flow rate (suction flow rate) corresponding to Phase 1 as shown in FIG. 5G, but the first pump flow rate is 2 of the second pump flow rate at Phase 1 as shown in FIG. 5F. Double the flow rate. That is, the target total flow rate is obtained by discharging the second pump with a negative flow rate supplemented by the first pump.

  In the second and subsequent cycles, only Phase 1 is different from the first cycle. Hereinafter, only Phase 1 in the second and subsequent cycles will be described. In the Phase 1 stroke in the second and subsequent cycles, as shown in FIGS. 5B and 5D, the active valve 5 is changed from “closed” to “open”. Therefore, as shown in FIG. 1, the second pressurizing chamber 202 is cut off from the first pressurizing chamber 102, and the first pressurizing chamber 102 is connected to the storage tank 51 via the active valve 5. As shown in FIG. 5C, the first plunger 101 moves from the top dead center toward the bottom dead center at a predetermined speed, and the suction process of the first pump is performed. As shown in FIG. 5E, the second plunger 201 moves from the bottom dead center toward the top dead center at a predetermined speed, and the discharge process of the second pump is performed. Therefore, as shown in FIG. 5G, the second pump flow rate is a predetermined value corresponding to the moving speed of the second plunger 201, but as shown in FIG. 5F, the first pump flow rate is zero. Here, the reason why the suction process of the first pump does not affect the flow rate of the second pump is that the second pressure chamber 202 is blocked from the first pressure chamber 102 by the active valve 5 as described above. is there.

  In the above example, as in the process of Phase 2-1, the process of operating the first plunger to pressurize until the pressure in the first pressurizing chamber reaches the pressure in the second pressurizing chamber is incorporated. By incorporating such a process, pressure fluctuations caused by the switching timing of the active valve and the compressibility of the eluent and the elastic deformation of the sealing material (this pressure fluctuation affects the flow rate and causes pulsation that cannot be ignored). It can be effectively avoided. In the case of liquid feeding at a microliter level flow rate, there is a flow rate range in which the above pressure fluctuation occurs. Therefore, it is preferable to incorporate the Phase 2-1 stroke in such a flow rate region.

  As shown in FIG. 5H, the pump device PS can send the eluent at a target flow rate Qset with high accuracy, as shown in FIG. 5H.

  Next, the third liquid supply amount mode in the microliter level flow rate liquid supply will be described. The third liquid supply amount mode is used in a flow rate region where the flow rate is larger than that of the second liquid supply amount mode. FIG. 6 shows an operation mode of the pump device PS in the third liquid feeding amount mode. A to H in FIG. 6 correspond to A to H in FIG.

  First, in the first half stroke, the drain valve 9 is closed as shown in FIG. 6A, and the active valve 5 is closed as shown in FIGS. 6B and 6D. Therefore, as shown in FIG. 2, the first pressurizing chamber 102 is connected to the second pressurizing chamber 202 via the active valve 5. As shown in FIG. 6C, the first plunger 101 is moved from the bottom dead center to the top dead center at a predetermined speed, and the discharge process of the first pump is performed. As shown in FIG. 6E, since the second plunger 201 is disposed together, the second pump is not substantially operated. Therefore, as shown in FIG. 6F, the first pump flow rate is a predetermined value corresponding to the moving speed of the first plunger 101, but as shown in FIG. 6G, the second pump flow rate is zero.

  Next, in the latter half of the stroke, as shown in FIGS. 6B and 6D, the active valve 5 is changed from “closed” to “open”. Therefore, as shown in FIG. 1, the second pressurizing chamber 202 is cut off from the first pressurizing chamber 102. As shown in FIG. 6C, the first plunger 101 moves from the top dead center toward the bottom dead center at a predetermined speed, and the suction process of the first pump is performed. As shown in FIG. 6E, the second plunger 201 moves from the bottom dead center toward the top dead center at a predetermined speed, and the discharge process of the second pump is performed. Accordingly, as shown in FIG. 6G, the second pump flow rate is a predetermined value corresponding to the moving speed of the second plunger 201, but as shown in FIG. 6F, the first pump flow rate is zero. That is, as shown in FIG. 6H, the target total flow rate Qset is obtained by the operation of alternately repeating the discharge and suction strokes of the first pump and the second pump.

  As described above, according to the third liquid supply amount mode, liquid supply at a microliter level flow rate can be stably performed by a simple and simple opening / closing operation of the active valve.

  In this embodiment, the active valve is a 6-port valve with 3 positions. However, the present invention is not limited to this, and the number of ports is not limited as long as the position is 3 positions.

  In the present invention, as described above, the liquid feeding amount mode is changed between the case of feeding an extremely low flow rate of nanoliter level and the case of feeding a low flow rate of microliter level. Hereinafter, the concept of properly using the liquid supply amount mode will be described. Basically, in the case of a plunger-type pump, the operation of a pump that supplies liquid with high accuracy without pulsation at a low flow rate is a one-push operation. This is an operation as a so-called syringe pump. The syringe type has a merit that the problem of flow rate pulsation (pressure pulsation) can be avoided, but has a demerit that “continuous liquid feeding” cannot be performed. On the other hand, the repetitive operation (reciprocating operation) has the merit that “continuous liquid feeding” is possible, but has the demerit that a flow rate pulsation that cannot be ignored because the plunger suction process is indispensable during continuous liquid feeding. is doing.

  In the present invention, when the liquid is fed in the extremely low flow rate range of the nanoliter level, the first liquid feed mode in which the plunger is operated in a single push operation mode is set as the first liquid feed mode, and the microliter level low flow rate range is set. By using the second and third liquid delivery mode by repetitive operation that causes the plunger to reciprocate, the advantages of one-push operation and repetitive operation can be effectively utilized in one pump device. Thus, a single pump device can realize liquid feeding in a wide flow range from a very low flow rate of nanoliter level to a low flow rate of microliter level.

  The above description is based on rough flow rate standards such as the nanoliter level and the microliter level, but the flow rate for switching the liquid feeding flow rate mode is generally determined as follows. The “flow rate (or flow velocity) per stroke” of the plunger in the pump device is determined by the plunger diameter and the plunger stroke length, which are the specifications of the plunger. Therefore, if the specifications of the plunger are determined, it is based on the “analysis time” or “measurement time” and “discharge flow rate (liquid feed amount per minute)” required by the liquid chromatograph system (or the user who uses it). The switching flow rate can be determined.

  As a specific example, if the plunger diameter is φ2 μm and the stroke length is 8 μm, the flow rate (or flow velocity) per stroke of the plunger is about 25 μl / min. If the required discharge flow rate is 500 nl / min, the time required for one stroke of the plunger is about 50 minutes. In this case, if the “analysis time” or “measurement time” is 30 minutes, it is sufficient to make one stroke of the plunger. Therefore, the pump only needs to be operated once.

  On the other hand, if the required discharge flow rate is 100 μl / min, the time required for the plunger to make one stroke is 0.25 minutes. In this case, if the “analysis time” or “measurement time” is 30 minutes, one plunger stroke is insufficient. Therefore, repeated operation (reciprocating operation) is performed.

  That is, assuming that Qs is the flow rate (or flow velocity) per stroke of the plunger, Qd is the required discharge flow rate, and Td is the required analysis time (or measurement time), and if Qs / Qd = T ≧ Td, the plunger is pushed once. In the above example, if Qs / Qd = T <Td, the liquid supply mode by the repetitive operation that causes the plunger to reciprocate (the above example) Then, the second and third liquid feeding amount modes) are set.

  When performing analysis or measurement using the liquid chromatograph system of this example, a map that determines the operation method of the pump device for the target flow rate and measurement time is created in advance, and the liquid chromatograph system is automatically used using this map. It is also possible to start up. For example, the user inputs a target flow rate or measurement time. The liquid chromatograph system reads the optimum pump operation mode for the target flow rate or measurement time from the map, and automatically starts the pump.

  Next, an example of a case where the liquid feeding system (liquid chromatograph pump system) according to the present invention is applied to a high pressure gradient operation system will be described. FIG. 7 shows a configuration of a high-pressure gradient operation system to which the liquid feeding system according to the present invention is applied. In the high-pressure gradient operation system, high-pressure gradient operation is performed using two liquid feeding systems. The high-pressure gradient operation system of this example includes two pump devices 10a and 10b, an injector 53, a column 54, a detector 55, a storage tank 56, a mixer 62, and a main controller 70. The pump devices 10a and 10b are the same as the pump device PS in FIG. The injector 53, the column 54, the detector 55, and the storage tank 56 are the same as those in FIG. In FIG. 7, a part of the constituent elements of the pump devices 10 a and 10 b is omitted from being complicated to avoid complication.

  First pressure sensors 60a and 60b are provided in the discharge passages of the first pumps of the pump devices 10a and 10b, respectively, and second pressure sensors 61a and 61b are provided in the first pressurizing chambers of the pump devices 10a and 10b, respectively. Are provided. The discharge pipes 19a and 19b of the pump devices 10a and 10b are connected to a mixer 62. The discharge side of the mixer 62 is connected to the injector 53.

  FIG. 8 shows the relationship between the flow rates of the eluents sent by the two pump devices 10a and 10b in the high-pressure gradient operation system. The gradient operation refers to sending the liquid while changing the mixing ratio of the eluent A sent by the pump device 10a and the eluent B sent by the pump device 10b stepwise with time. That is, the ratio of the two liquid feeding flow rates Qa and Qb is changed while keeping the total liquid feeding flow rate (Qt = Qa + Qb) constant. As shown in FIG. 8A, the flow rate Qa of the first eluent A increases stepwise with time, for example, changes stepwise from Qa = 1 to 99. As shown in FIG. 8B, the flow rate Qb of the second eluent B decreases with time, and changes stepwise from Qb = 99 to 1, for example. As shown in FIG. 8C, the total liquid feeding flow rate Qt = Qa + Qb is constant, and its value is 100. The total liquid feeding flow rate Qt is the flow rate of the mixer 62. FIG. 8D shows the mixing ratio of both eluents A and B at the discharge point S of the mixer 62. The mixing ratio of the first eluent A and the second eluent B increases stepwise with time. For example, Qb / Qa = 1 to 99. In this example, the gradient is 100 steps. Therefore, when the total liquid feeding flow rate Qt is 1 μl / min, the minimum flow rate and resolution are 1/100, that is, 10 nl / min.

  FIG. 8E shows the discharge pressure of the pump device. The discharge pipes 19 a and 19 b of the two pump devices are connected to each other via a mixer 62. Neglecting the pressure drop or pressure loss due to the mixer 62, the discharge pressures of the two pump devices are the same. That is, the discharge pressure detected by the first pressure sensor 60a of the first pump device 10a is equal to the discharge pressure detected by the first pressure sensor 60b of the second pump device 10b. Furthermore, the discharge pressure detected by these pressure sensors 60 a and 60 b is equal to the discharge pressure of the mixer 62.

  As shown in FIG. 8C, even if the total liquid feeding flow rate Qt is constant, as shown in FIG. 8E, the discharge pressure of the pump changes by a maximum of about 1.5 to 2 times. This is because when the mixing ratio of the two eluents changes, the fluid resistance when passing through the column changes. If the pump discharge pressure is kept constant, the total liquid supply flow rate Qt is not constant. However, the relationship between the mixing ratio and the pressure fluctuation is known from past experimental data. Therefore, the pressure fluctuation curve when the total liquid feeding flow rate Qt is constant can be predicted. Therefore, the total delivery flow rate Qt can be kept constant by measuring the discharge pressure of the mixer 62, comparing it with the predicted value of the pressure fluctuation curve, and driving the pump device using the deviation between them as a feedback signal. The solid curve in FIG. 8E is a measured value of the pump discharge pressure, and the broken curve is a target pressure obtained from past experimental data.

  As shown in FIG. 7, the output of the first pressure sensor 60 a provided in the first pump device is fed back to the main controller 70. The main controller 70 compares the measured value from the first pressure sensor 60a with the target pressure, and obtains the deviation between them. This deviation is transmitted to the controllers 50a and 50b of the pump devices 10a and 10b. The controllers 50a and 50b control the pump devices 10a and 10b based on the deviation.

  When the discharge pressure of the pump devices 10a and 10b is lower than the target pressure, the total liquid feeding flow rate (Qt = Qa + Qb) is decreased. Therefore, the total liquid feeding flow rate may be increased. However, it is unclear which of the two liquid feeding flow rates Qa and Qb is greatly reduced. For example, when it is actually determined that the second liquid supply flow rate Qb is decreasing while the first liquid supply flow rate Qa is decreasing, and the second liquid supply flow rate Qb is increased, The accuracy of the mixing ratio deteriorates. This is a problem called mutual interference in gradient operation.

  In this example, it is assumed that the two liquid feeding flow rates Qa and Qb increase or decrease at the same rate. Therefore, as shown in FIG. 8F, a feedback gain proportional to the flow rate ratio is given to the two liquid feeding flow rates Qa and Qb. That is, proportional control is performed. For example, when the ratio Qa: Qb of the two liquid flow rates is 20:80, the feedback gains of the two liquid flow rates Qa and Qb are given by (20/100) × K and (80/100) × K, respectively. . K is a constant. If the total liquid flow rate Qt is insufficient by 5, the command values for the two pumps are given by 20+ (20/100) × K × 5 and 80+ (80/100) × K × 5, respectively. For example, if K is 1, the former is 21 and the latter is 84. According to this method, a decrease in the accuracy of the mixing ratio due to the difference between the two pump devices is inevitable, but mutual interference can be avoided.

  The high pressure gradient operation system as described above is excellent in mixing accuracy and enables stable liquid feeding.

  Next, an embodiment of a two-dimensional high performance liquid chromatograph / mass spectrometry system configured by applying the liquid feeding system according to the present invention will be described. FIG. 9 shows a configuration example of a two-dimensional high performance liquid chromatograph / mass spectrometry system. The two-dimensional high performance liquid chromatograph / mass spectrometry system of this example includes a front-stage separation unit, a desalting unit, a rear-stage separation unit, and a mass analysis unit, and further switches the connection relation between the control unit 79 configured by a computer and each unit. A six-way valve 80 is included. The front stage separation unit includes a pump device 71, an autosampler 72, and an ion exchange column 73, the desalting unit includes a pump device 74 and a trap column 75, and the rear stage separation unit includes a gradient liquid feeding unit 76 and a reverse phase column. 77, and the mass spectrometer includes a mass spectrometer 78.

  In the former separation unit, a pump device 71 configured in the same manner as the pump device PS of FIG. 1 sends the eluent quantitatively to the ion exchange column 73 under the control of the control unit 79. A sample solution containing a sample to be analyzed is introduced from the autosampler 72. A part of the sample components introduced from the autosampler 72 is separated by the first eluent in the ion exchange column 73 and flows out from the ion exchange column 73, and is connected through a 6-way valve 80. The trap column 75 traps each component in a separated state. Each separation component trapped in the trap column 75 is analyzed through a series of operations such as desalting, reverse phase gradient separation, and mass spectrometry which will be described later. The eluent flow rate in the pre-stage separation unit is preferably 200 μl / min or less in order to enable separation with a very small amount of a very small sample.

  In the desalting section, the desalting treatment of each separated component by the ion exchange column 73 is performed. In the desalting treatment, when the separated component is introduced as it is into the latter-stage separation unit which is a reverse phase separation system, the salt contained in the separated component is mixed into the mass spectrometer 78 of the subsequent mass analysis unit and the mass spectrometer 78 This is done to prevent the analysis performance from being affected.

  In the subsequent separation section, each separation component is desalted in the trap column 75, and then the six-way valve 80 is rotated to switch the flow path. Then, each separation component is sent to the reverse phase column 77 and is gradient-separated by the eluent for reverse phase separation. The gradient liquid feeding unit 76 feeds a mixed eluent obtained by mixing two types of eluents at an arbitrary mixing ratio in the same manner as the gradient operation described above for the high pressure gradient operation system. Specifically, by mixing two kinds of eluents fed by each of two pump devices 76a and 76b configured in the same manner as the pump device PS of FIG. It introduce | transduces into the reverse phase column 77 as a mixed eluent. The mixing ratio of the mixed eluent is changed stepwise by the control of the control unit 79, and each of the separated components is further separated into each component based on the elution intensity according to the mixing ratio of the mixed eluent. The eluent flow rate in the subsequent separation section is preferably 100 μl / min or less in order to enable separation with a very high resolution with respect to a very small amount of sample. In some cases, 50 nl / min or less may be suitable.

  In the mass spectrometer, the mass spectrometer 78 performs qualitative and quantitative analysis of each component separated into single components by the above-described two-stage separation. As an interface between the high performance liquid chromatograph and the mass spectrometer, ESI (electrospray ionization), APCI (atmospheric pressure chemical ionization), or the like is used. As the mass spectrometer, configurations such as a time-of-flight type and an ion trap type are applied.

  The two-dimensional high-performance liquid chromatograph / mass spectrometry system as described above exhibits high resolution in, for example, proteome analysis, enables high-precision automatic analysis, and increases processing efficiency. This greatly contributes to the liquid feeding capacity of the pump devices (71, 74, 76a, 76b) used in this system. In proteome analysis, various proteins are extracted from the collected cells and analyzed, but the amount of each protein contained in the cells is extremely small and cannot be proliferated. Therefore, in order to increase the detection sensitivity of the two-dimensional high-performance liquid chromatograph / mass spectrometry system, it is required that the liquid chromatograph system can also deliver an extremely low flow rate. In proteome analysis, several hours of analysis time is required from the introduction of a sample to data processing. The pump apparatus (71, 74, 76a, 76b), which is a liquid chromatograph pump system according to the present invention, can deliver liquids in a wide liquid supply range from nanoliter level with extremely low flow rate to microliter level with low flow rate. This is possible with a single pump, and it is possible to switch the liquid-feeding operation mode in a short time, satisfying the above-mentioned conditions required in proteomic analysis, so that in proteomic analysis It enables high-precision automatic analysis and increases processing efficiency.

  FIG. 10 shows a configuration example of a liquid chromatograph system to which the liquid feeding system according to the second embodiment is applied. The liquid chromatograph system of this example is basically the same as the liquid chromatograph system of FIG. Therefore, elements common to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  In the liquid chromatograph system of this example, the pump device PS ′ is configured by the liquid feeding system (liquid chromatograph pump system) according to the second embodiment of the present invention. The pump device PS ′ is a single plunger pump (first pump) 1 and a second plunger, which are formed separately from each other, whereas the pump device PS in the first embodiment has an integral structure. The pump (second pump) 2 is combined in parallel. A storage tank 51-1 and a deaeration device 14-1 are connected to the first pump 1 via a suction pipe 16-1, and a storage tank 51-2 and a deaeration device 14-2 are connected to the second pump 2. Are connected via a suction pipe 16-2. The first pump 1 is provided with a suction check valve 105 in the suction passage 103, a discharge check valve 106 is provided in the discharge passage 104, and the second pump 2 is provided with a suction check valve 205 in the suction passage 203. A discharge check valve 206 is provided in the passage 204. These check valves realize the function that the active valve 5 of FIG. That is, it functions as a flow path switching means for switching the liquid feeding amount mode. The first pump 1 and the second pump 2 are individually connected to the injector 53 through a common discharge pipe 19. The discharge pipe 19 is provided with a drain valve 9 and a pressure sensor 63. The above is the main difference in structure of the pump device PS ′ with respect to the pump device PS in the first embodiment.

  Next, the operation of the pump device PS ′ will be described. The operation of the pump device PS ′ is basically the same as that of the pump device PS of FIG. In the following, the operation unique to the pump device PS ′ will be mainly described. In the bubble discharge / eluent filling, the drain valve 9 is opened, and both the first and second pumps 1 and 2 are operated to discharge the bubbles and fill the eluent. In the start-up operation, the drain valve 9 is closed and only the first plunger 101 is operated so that the discharge pressure of the first pump 1 reaches the target pressure. When the discharge pressure reaches the target pressure, the operation proceeds to steady operation. In the steady operation, the first pump 1 is stopped and only the second pump 2 is operated with the drain valve 9 closed. The second plunger 201 is pushed into the second pressurizing chamber 202 at a low speed. Thereby, the liquid is fed at a predetermined flow rate while maintaining the discharge pressure of the second pump 2 at the target pressure. The above is the operation mode for the nanoliter flow rate in the pump device PS ′. In the operation mode of the microliter level flow rate, the first and second pumps 1 and 2 are made to perform a discharge / suction process alternately while monitoring the pressure in the respective pressurizing chambers. Deliver liquid.

  As described above, the pump device PS ′ according to the present embodiment has a structure in which the first and second pumps 1 and 2 formed separately are connected by piping. The burden of maintenance work such as replacement can be reduced. In addition, advantages such as improved layout of the equipment can be obtained.

  The present invention relates to a liquid feeding system, for example, enables liquid feeding in a wide range of flow rates from a very low flow rate of nanoliter level to a low flow rate of microliter level with a single pump. It can be widely used in the field of chromatographs.

It is a figure which shows the state of the active valve while showing the structure of the liquid chromatograph system to which the liquid feeding system by 1st Embodiment is applied. It is a figure which shows the structure of the liquid chromatograph system to which the liquid feeding system by 1st Embodiment is applied, and shows the state of an active valve being "closed." It is a figure which shows the operation mode of the pump apparatus in 1st liquid supply amount mode. It is a figure which shows the "closed-closed" state which appears on an active valve in 2nd liquid feeding amount mode. It is a figure which shows the operation mode of the pump apparatus in 2nd liquid feeding amount mode. It is a figure which shows the operation mode of pump apparatus PS in 3rd liquid feeding amount mode. It is a figure which shows the structure of a high pressure gradient driving | operation system. It is a figure which shows the relationship of the eluent flow volume of each of the two pump apparatuses in a high pressure gradient driving | operation system. It is a figure which shows the structure of a two-dimensional high performance liquid chromatograph / mass spectrometry system. It is a figure which shows the structure of the liquid chromatograph system to which the liquid feeding system by 2nd Embodiment is applied.

Explanation of symbols

5 Active valve (channel switching means)
5a to 5h Port 100 First pump 200 Second pump PS Pump device (liquid feeding system)

Claims (6)

In the liquid feeding system in which the first pump and the second pump that pressurize and feed the liquid are combined so as to cooperate with each other,
A flow path switching means is provided, and the liquid flow path is switched by the flow path switching means, so that one of a plurality of operation modes having different cooperative states of the first and second pumps is selected. According to the selection of the operation mode, liquid feeding can be performed by switching to any one of a plurality of liquid feeding amount modes having different liquid feeding flow rate ranges. Liquid system.   A liquid-feeding amount mode in which only one of the first and second pumps is used for liquid feeding during a steady operation in which liquid is fed while maintaining a predetermined pressure and flow rate, and both the first and second pumps during the steady operation. The liquid feeding system according to claim 1, wherein a liquid feeding amount mode in which a pump is used for liquid feeding is included in the plurality of liquid feeding amount modes.   The flow rate used as the reference for switching the liquid supply amount mode is determined based on an analysis time or a measurement time and a discharge flow rate required in a liquid supply target system. Liquid feeding system.   The flow path switching means has a plurality of ports, and is formed of an active valve that switches a flow path by switching connection of the plurality of ports. The liquid feeding system described.   The liquid feeding system according to any one of claims 1 to 4, wherein a range of a liquid feeding flow rate over the plurality of liquid feeding amount modes is 1 nanoliter per minute to 200 microliters per minute. The first and second pumps have a first pump and a second pump that pressurize and feed the eluent, and the first and second pumps are located upstream in the liquid feed direction of the eluent. In the liquid feeding system that is configured to be combined with each other so that the second pumps can be in a coordinated operation with each other on the downstream side, and used in a liquid chromatograph system,
A flow path switching means, and switching the flow path of the eluent by the flow path switching means, so that any one of a plurality of operation modes having different cooperative states of the first and second pumps can be obtained. According to the selection of the operation mode, it is possible to perform liquid feeding by switching to any one of a plurality of liquid feeding amount modes having different liquid feeding flow rate ranges. Liquid delivery system.

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