JPH1150967A - Pump device, method for controlling it, and recording medium recording its control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the change of the mixing ratio of liquid caused by interference of pressure between pumps. SOLUTION: A double-speed rotating time function is input from a keyboard by an operator and stored (S1). When a motor is rotated (S2), whether the motor is in the rotational speed priority control section or not is judged (S3). If Yes, the motor is rotated (S4) at the preset constant speed, pressure on the pump output side in the section is detected as reference pressure and stored (S5). While, the answer in the step S3 is No, the detected and stored reference pressure is substituted in the double-speed rotating time function input from the keyboard, the double-speed rotating time corresponding to the reference pressure is found (S6), and the motor is forcibly rotated (S7) at double speed through the double-speed rotating time. The step after the step S3 is similarly repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump device, a control method therefor, and a recording medium on which a control program is recorded, in particular, a plurality of eluents are separately sent so as to obtain a mixed solution in a high-pressure gradient liquid chromatograph. The present invention relates to a pump device, a control method therefor, and a recording medium storing a control program therefor.

[0002]

2. Description of the Related Art In a high-pressure gradient liquid chromatograph in which a sample is analyzed by changing the mixing ratio of a plurality of eluents supplied to a separation column, thereby changing the composition of the mixture, each eluent is separated into separate eluents. The liquid is sent and mixed using a pump, and the mixed liquid is supplied to a separation column.

However, as described later, there is a problem that the mixing ratio of the eluent changes due to pressure interference between the pumps.

An object of the present invention is to provide a pump device suitable for preventing a change in a mixing ratio of liquid due to pressure interference between pumps, a control method thereof, and a recording medium on which a control program is recorded.

[0005]

SUMMARY OF THE INVENTION According to one aspect, the present invention is directed to a pump device, the feature of which is a plurality of pumps for separately delivering a plurality of liquids to obtain a mixture thereof. Wherein each of the plurality of pumps rotates the motor at a predetermined constant speed throughout a first period periodically formed through rotation of the motor. Means for controlling the motor and means for storing a predetermined relationship between a reference pressure and a length of a second period formed in the same cycle as the first period through rotation of the motor. And a means for detecting the pressure of the liquid fed during the first period as the reference pressure, wherein the control means controls the constant speed higher than the predetermined speed throughout the second period. To control the motor so as to rotate the motor It said control means is to be determined from a predetermined relationship which is the storage based on the length of the second period to the detected pressure.

The present invention, in another aspect, is directed to a method of controlling a pump device, the feature of which is to pump a plurality of liquids separately to obtain a mixture thereof, each of which is a motor. A method of controlling a pump device including a plurality of pumps, the pump comprising: a plurality of pumps each including a plurality of pumps. Rotating the motor; storing a predetermined relationship between a reference pressure and the length of a second period formed in the same cycle as the first period through rotation of the motor; Detecting the pressure of the liquid sent during the period as the reference pressure, and rotating the motor at a constant speed higher than the predetermined speed throughout the second period. The length of the period of 2 is detected It was based on the pressure lies in obtaining from a predetermined relationship that is the storage.

According to a further aspect of the present invention, there is provided a pump apparatus comprising a plurality of pumps each including a motor for separately feeding a plurality of liquids so as to obtain a mixture thereof. The control program is directed to a recording medium on which a control program for controlling the pump is controlled by a pump for each pump during a first period periodically formed through rotation of the motor. The motor is rotated at a predetermined constant speed, and a predetermined relationship between a reference pressure and a length of a second period formed in the same cycle as the first period through rotation of the motor. And the pressure of the liquid fed during the first period is detected as the reference pressure, and the motor is maintained at a constant speed higher than the predetermined speed throughout the second period. Rotated It is intended to let determined from a predetermined relationship which is the storage based on the length of the second period to the detected pressure.

[0008]

FIG. 2 shows an embodiment of a high pressure gradient liquid chromatograph using a pump device according to the present invention. The eluents 1 and 2 are separately sent by the pump devices 3 and 4, respectively, and merge at the junction 9;
After being mixed, the mixed solution is supplied to the separation column 5.
The amount of eluent sent by the pumps 3 and 4 can be changed. Therefore, when the sample is introduced into the separation column 5 by the sample introduction device 6 and the mixing ratio of the mixed solution is sequentially changed, the components constituting the sample while the sample passes through the separation column 5 by the mixed solution. Are separated from each other, and the separated sample components are detected by the detector 7. The detected signal of the sample component is guided to the data processing device 8, where necessary processing is performed.

FIG. 3 shows an embodiment of a pump device according to the present invention. 2, eluents 1 and 2, pumps 3 and 4, and a junction 9 correspond to those in FIG. 2, respectively. The pump 3 includes pump units 23 and 24.
The plungers 12 and 13 inserted into the cylinders 10 and 11 of the pump units 23 and 24 reciprocate by rotation of the cams 15 and 16 provided on the cam shaft 14, whereby the valves 17 and 18 open and close,
The eluent 1 is sucked into the cylinders 10 and 11, and the sucked eluent is discharged to the junction 9 side (pump output side).

The camshaft 14 is rotated by a motor 20 connected to one end of the camshaft 14, and the motor 20 is controlled by a control device 21 including a computer. The rotation speed of the motor 20 can be set by inputting the value from a keyboard 22 connected to the control device 21.

At the other end of the cam shaft 15, a position detecting device 25 is provided, which detects the rotational position of the cam shaft 14. The detected signal is introduced to the control device 21. A pressure detector 26 for detecting the pressure is provided on the output side of the pump 3, and a signal of the detected pressure is guided to the control device 21.

The pump 4 has the same configuration as the pump 3, and therefore, details thereof are omitted in the drawing.

The eluents 1 and 2 discharged from the pumps 3 and 4 join at a junction 9 and are mixed to form a separation column 5.
(FIG. 2).

FIG. 4 shows the relationship between the suction and discharge of the pump units 23 and 24 of the pump 3 and the opening and closing of the valves 17 and 18. Referring to the figure, one cycle of the pump 3 is divided into three regions R1 to R3. Region R1
, The pump unit 23 is in the suction mode (the suction amount is 3Q per unit time), the pump unit 24 is in the discharge mode (the discharge amount is Q per unit time), and in the region R2, both the pump units 23 and 24 discharge. In the region R3, the pump unit 23 operates in the discharge mode (the discharge amount is Q / 2 per unit time).
/ 2) + Q), and the pump unit 24 rotates at a constant rotation speed (the number of rotations N per unit time) so that the pump 20 is operated in the suction mode (the suction amount is 3Q / 2 per unit time). Shall be performed. Then, in the region R1, the valve 17 is opened and the valve 18 is closed, and in the regions R2 and R3, the valve 17 is closed and the valve 18 is opened.

However, when the pump output side is at a high pressure (for example, 140 kg / cm ² ), the pump unit 2
When the mode 3 is switched from the suction mode to the discharge mode, the valve 18 is not initially opened (that is, in the first region r of the region R2). This is because the high pressure is applied to the valve 18 using the eluent 1 as a medium. Also,
The area r changes depending on the compressibility of the eluent used.
Accordingly, since there is no discharge by the pump unit 23 and only the discharge by the pump unit 24 during the region r, the total discharge amount is halved, and a pulsating flow occurs.

In order to solve this problem, the following measures are usually taken. First, the position where the pump unit 23 switches from the suction mode to the discharge mode is detected. This is possible by detecting the position of the bottom dead center of the plunger 12 with the position detector 25. Further, if there is no discharge by the pump unit 23 but only discharge by the pump unit 24, the pressure on the pump output side decreases. Therefore, this pressure drop is detected by the pressure detector 26.
Therefore, the rotational speed of the motor 20 is doubled only when both the position detection signal and the pressure drop detection signal are detected (AND condition). That is, the number of rotations per unit time is set to 2N. This allows the pump unit 24 to compensate for the amount not discharged by the pump unit 23.
Discharges twice the flow rate.

Meanwhile, when the valve 18 is opened, the pressure on the pump output side increases.
6 to detect. Since the discharge is also performed by the pump unit 23, the rotation of the motor 20 is returned from double speed rotation to half its speed, that is, the original rotation, based on the detected pressure rise signal. in this way,
In the regions R1 and R3, the rotation speed priority control is performed. In the region R2, when the pressure-responsive rotation speed is switched, the compression of the eluent 1 when the pump unit 23 changes from the suction mode to the discharge mode. The flow rate change due to the flow rate is prevented, and as a result, a constant flow rate (Q) without pulsating flow can be supplied.

The above fact is exactly the same for the pump 4.

However, it was found that when the double speed control regions of the respective pumps 3 and 4 overlap, the mixing ratio of the eluent changes due to pressure interference between the pumps. That is, when one of the pumps 3 and 4 is rotating at double speed and the other ends at double speed, the pressure on the pump output side rises, and the double speed rotation of one of the pumps also stops at that time in response to the rise in pressure. Resulting in. Since this stop is performed earlier than the original stop, for one of the pumps, the pressure on the pump output side increases by opening the valve on the input side from the time of the stop, and the discharge by both pump units is stopped. Until the start of the operation, the output flow rate is halved, which causes a problem that the mixing ratio changes.

In the embodiment of the present invention, it is possible to prevent the change of the mixing ratio due to the pressure interference between the pumps. A control method as an example of the pump device according to the present invention including this point will be described with reference to FIGS.

FIG. 1 shows a control flow as an example of a pump device according to the present invention. Computer of control device 21
The computer includes a ROM which is a recording medium on which a control program for controlling the pump device by the computer is recorded. According to the control program recorded on the ROM, the computer executes the control flow shown in FIG. The illustrated control is performed for each of the pumps 3 and 4. That is,
First, the double-speed rotation time function is key-operated by the operator.
Input from the memory 22 and stored (S1). This function is, for example, a function of a first-order approximation. That is, the function is represented by Rt = A · Ps + B, where Rt is the double-speed rotation time, that is, the time corresponding to the region r in FIG. 4, and Ps is the reference pressure. However, A and B
Is a constant, which is experimentally determined as described later.

When the motor 20 is rotated (S2), it is determined whether or not the motor is in the rotation speed priority control section, that is, the section corresponding to the regions R1 and R3 in FIG. 4 (S3). This determination can be made by monitoring the output signal of the position detector 25. If the answer is "Yes", the motor 20 is rotated at a predetermined constant speed (S4), and the pressure on the pump output side in that section is detected by the detector 26 as the reference pressure Ps. It is stored (S5). The pressure detection time in that section may be the time immediately before the region r in the region R1.

The end point is determined not only in the rotation speed priority section, but also when both the position detection signal from the position detector 25 and the pressure drop detection signal on the pump output side from the pressure detector 26 are present. It is also the starting point of the double speed rotation period).

On the other hand, if the answer in step S3 is "N
o ”, the detected and stored reference pressure Ps
Is substituted into the double speed rotation time function input from the keyboard 22, a double speed rotation time Rt corresponding to the reference pressure is obtained (S6), and the motor 20 is forcibly forced through this double speed rotation time. Rotate at double speed (S7). Steps subsequent to step S3 are similarly repeated thereafter.

As described above, the double speed rotation of the motor 20 is forcibly performed through the double speed rotation time set in accordance with the pressure on the pump output side during the rotation speed priority section, so that the double speed period of the pumps 3 and 4 is increased. Overlaps, and while one of the pumps 3 and 4 is rotating at a double speed, the double speed rotation of the other pump ends and the pressure on the pump output side drops, the double speed rotation of one pump decreases the pressure. It is continued in response to. Therefore, a change in the mixing ratio due to mutual pressure interference is prevented.

FIG. 5 is a flow chart for obtaining the double speed rotation time function Rt = A.Ps + B input from the keyboard 22 in FIG. 1, specifically, the constants A and B therein by actual measurement. . This flow is executed individually for each of the pumps 3 and 4. However, while this flow is being performed for one pump, the operation of the other pump is stopped.

First, it is determined whether to change the pressure on the pump output side (S1). The answer is "Yes"
If so, the pressure is set to a certain value (S2). Subsequently, it is determined whether or not the section is the rotation speed priority control section (S
3), the answer is if "Yes", motor at a constant rotational speed predetermined - by rotating the motor 20 (S4), for detecting a pressure (e.g., Ps ₁₎ of pump output side at that time as a reference pressure (S5).

On the other hand, if the answer in step S3 is "N
o For "mode - the motor 20 is speed rotation (S6), the pressure in the pump output side seek speed rotation time Rt ₁ to be set when a Ps ₁ (S7), and stores that value (S8). The double-speed rotation time Rt ₁ is obtained by detecting the time point at which the pressure on the pump output side rises while continuing the double-speed rotation by the pressure detector 26 and measuring the time until that time point.

The above steps are repeated once again,
The pressure set on the pump output side is set to Ps
_The double speed rotation time Rt2 to be set when the value is ₂ is obtained. Thereafter, an answer of "No" is given in determining whether to change the pressure on the pump output side, and step S
In step 9, a double speed rotation time function Rt = A · Ps + B, specifically, constants A and B therein are obtained. This is obtained by solving a two-way simultaneous linear equations based on respective measured the speed rotation time Rt ₁ and Rt ₂ when the pressure of the pump output side is set to Ps ₁ and Ps _2. Of course, the flow of FIG. 5 may be repeated three or more times.

In the case of a linear function having no intercept B, that is, a linear function in which the double-speed rotation time function Rt becomes zero when the reference pressure Ps is zero, the constant A is obtained by executing the flow of FIG. 5 only once. be able to. Also, instead of individually operating the pumps 3 and 4 to measure the double-speed rotation time, the pumps 3 and 4 are simultaneously operated, and the pump output is maintained without changing the mixing ratio and the flow rate within a range where the double-speed rotation periods do not overlap. The side pressure may be changed and the double speed rotation time of each pump at that time may be measured. Further, by operating the pumps 3 and 4 simultaneously, changing the pressure on the pump output side without changing the mixing ratio and the flow rate, and measuring the double speed rotation time of each pump over a plurality of cycles,
The average value may be obtained. In this case as well, an error occurs in the mixture ratio, but fluctuation of the mixture ratio is prevented.

In FIG. 4, the motor 20 is controlled at the double speed in the region r because the discharge amounts of both pump units in the region R2 are equal.
If the discharge amounts of both pump units are not equal, the rotation speed control of the motor in the region r is not double speed control, but is speed increase control in accordance with the discharge ratio. Therefore, in that case, the term "speed increase" should be used instead of the term "double speed".

In the embodiment, the double speed rotation time function is approximated by a linear expression, but this may be approximated by a polynomial expression. The polynomial in that case is B + APs + CPs ² + DPs ³
...

As is apparent from the above description, FIG. 1 shows a control flow as an example of a pump device according to the present invention.
FIG. 5 shows a flow for obtaining the double-speed rotation time function Rt = A.Ps + B input from the keyboard 22 in FIG. 1, specifically, constants A and B therein by actual measurement. If the execution of the flow 1 is called a control mode, and the execution of the flow of FIG. 5 is called a measurement mode, those modes can be switched manually or automatically. May be performed.

FIG. 6 shows an automatic switching flow between the control mode and the measurement mode. First, the measurement mode is executed (S1). Next, it is determined whether or not a sample introduction signal is output from the sample introduction device 6 of FIG. 2 (S2). If the answer is "Yes", it is automatically determined based on the signal, that is, in synchronization with the introduction. The control mode is executed (S3).

[0035]

According to the present invention, there is provided a pump apparatus suitable for preventing a change in a mixing ratio of liquid due to pressure interference between pumps, a control method thereof, and a recording medium recording a control program therefor. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a control flow as an example of a pump device according to the present invention.

FIG. 2 is a block diagram of an embodiment of a high pressure gradient liquid chromatograph using a pump device according to the present invention.

FIG. 3 is a conceptual diagram of one embodiment of a pump device according to the present invention.

FIG. 4 is a diagram showing a relationship between suction and discharge of a pump unit and opening and closing of a valve.

FIG. 5 is a view showing a flow for obtaining a double speed rotation time function input from a keyboard in FIG. 1 by actual measurement.

FIG. 6 shows a control mode and a measurement mode according to the present invention.
The figure which shows the automatic switching flow with a mode.

[Explanation of symbols]

1, 2: eluent, 3, 4: pump, 5: separation column,
6: sample introduction device, 7: detector, 8: data processing device,
9: confluence point, 10, 11: cylinder, 12, 13: plunger, 14: cam shaft, 15, 16: cam, 17, 1
8: Valve, 20: Motor, 21: Control device including computer, 22: Keyboard, 23, 24: Pump unit, 25: Position detector, 26: Pressure detector.

Claims (11)

[Claims] A plurality of pumps for separately feeding a plurality of liquids so as to obtain a mixed liquid thereof, wherein each of the plurality of pumps periodically rotates through a motor and rotation of the motor. Means for controlling the motor to rotate the motor at a predetermined constant speed throughout the first period formed; and the first period through a reference pressure and rotation of the motor. Means for storing a predetermined relationship with the length of a second period formed in the same cycle as the above, and means for detecting the pressure of the liquid sent during the first period as the reference pressure. And the control means controls the motor at a constant speed higher than the predetermined speed throughout the second period.
Controlling the motor to rotate the motor, wherein the control means determines the length of the second period from the stored predetermined relationship based on the detected pressure. And pump equipment. 2. The method of claim 1, wherein the predetermined relationship is represented by a linear function having a length of the second period of zero when the reference pressure is zero. Pump device. 3. The pump according to claim 1, wherein said predetermined relationship is represented by a linear function having a non-zero length of said second period when said reference pressure is zero. apparatus. 4. The pump device according to claim 1, wherein said predetermined relationship is represented by a polynomial. 5. A method for controlling a pump device including a plurality of pumps each including a motor, wherein the plurality of liquids are separately sent so as to obtain a mixed liquid thereof. Rotating the motor at a predetermined constant speed during a first period periodically formed through rotation of the motor; the same as the first period through rotation of the motor and a reference pressure. Storing a predetermined relationship with the length of a second period formed in a cycle, detecting a pressure of the liquid sent during the first period as the reference pressure, Rotating the motor at a constant speed higher than the predetermined speed throughout the period; and determining the length of the second period based on the detected pressure. The steps of finding from relationships Control method of the non-pump device. 6. The pump device according to claim 5, wherein said predetermined relationship is represented by a linear function. 7. The pump device according to claim 5, wherein said predetermined relationship is represented by a polynomial. 8. A control method for a pump device comprising a plurality of pumps each including a motor for separately feeding a plurality of liquids so as to obtain a mixed liquid thereof. Rotating the motor at a predetermined constant speed through a first period periodically formed by rotation of the motor for each pump; and rotating the motor through a reference pressure and rotation of the motor. Memorizing a predetermined relationship with a length of a second period formed in the same cycle as the first period, detecting a pressure of the liquid fed during the first period as the reference pressure; Performing the mode at a constant speed higher than the predetermined speed throughout the second period.
Rotating the motor and determining the length of the second period from the stored predetermined relationship based on the detected pressure, wherein in the measurement mode the stored A method for controlling a pump device, comprising the step of measuring a predetermined relationship to be performed. 9. The method according to claim 8, wherein the control mode and the measurement mode are selectively switched manually. 10. A separation column, a sample introduction device for introducing a sample into the separation column, and means for separately sending a plurality of eluents so as to obtain a mixture thereof, whereby the mixture is The pump device is used as the eluent liquid sending means in the liquid chromatograph for supplying the separation column and separating the sample introduced into the separation column,
9. The control method according to claim 8, wherein the control mode and the measurement mode are switched in synchronization with the sample introduction. 11. A control program for controlling, by a computer, a pump device provided with a plurality of pumps each including a motor for separately feeding a plurality of liquids so as to obtain a mixed liquid thereof. A recording medium, wherein the control program rotates the motor at a predetermined constant speed during a first period periodically formed by rotation of the motor for each pump; A predetermined relationship between the pressure and the length of a second period formed in the same cycle as the first period through the rotation of the motor is stored, and the liquid sent during the first period is stored. The pressure of the liquid is detected as the reference pressure, the motor is rotated at a constant speed higher than the predetermined speed throughout the second period, and the length of the second period is detected. Based on pressure A recording medium recording a control program of the pump apparatus characterized by causing determined from a predetermined relationship that is the storage.