JPH02201071A - Liquid delivery device - Google Patents

Abstract

PURPOSE:To have no-ripple liquid delivery certainly and accurately all the time by calculating the acceleration finish angle on the basis of the predetermined optimum acceleration pattern, acceleration finish angle, acceleration factor, and acceleration start angle, and controlling the drive part according to the result from calculations. CONSTITUTION:A liquid delivery device equipped on a liquid chromatograpf 100 is furnished with a pump 70 and a damper 80, which discharges the liquid sucked under pumping action to perform non-ripple liquid delivery, and they are driven through cams 75, 85, respectively, mounted on a cam shaft 90 rotated by a pulse motor 91. Therein is also equipped a gate means 113 which emits as output the pressure in the reference division on the basis of outputs from a point-of-origin sensing means 111 and a pressure sensing means 112. A calculating means 115 calculates the actual acceleration finish angle on the basis of the acceleration finish angle, acceleration factor, and acceleration start angle given by a storing means 114 and the optimum acceleration pattern by an acceleration pattern calculating means 116, and according to the results from calculations the above-mentioned pulse motor 91 is controlled by a control means 110.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid feeding device suitable for use in a high performance liquid chromatography device.

(Prior Art) Next, a conventional example will be explained using the drawings. FIG. 8 is a configuration diagram showing a conventional liquid feeding device. In the figure, 1 is a tank storing, for example, an eluent, 2 is a tank containing a discharged liquid such as the eluent, 10 is a pump that sucks and discharges liquid from the tank 1, 11 is a plunger, and 12 is a spring that gives restoring force to the plunger 11, and 13 is the plunger 1.
A piston is connected to 1, 14 is a wheel provided on the end surface of the piston 13 opposite to the plunger, 15 is a first cam that drives the plunger 11 via the wheel 14 and the piston 13, and 16 is a wheel through which the plunger 11 moves in and out. 17 is a sealing material that seals the cylinder 16, 18 is a suction valve that opens when liquid is sucked into the cylinder 16, and one opens when liquid is discharged from the cylinder 16. It is a discharge valve.

20 is a damper that discharges the liquid sucked by the pump 10 and delivers the liquid in a non-pulsating manner; 21 is a plunger; 22 is a spring that provides restoring force to the plunger 21; and 23 is a piston connected to the plunger 21. , 24 is a wheel provided on the end surface of the piston 23 on the side opposite to the plunger, 25 is provided on the camshaft 30 on which the first cam 15 is provided, and the wheel 2
4, a second cam that drives the plunger 21 via the piston 23; 26, a cylinder into which the plunger 21 moves in and out to discharge/inhale liquid; and 27, a sealing material that seals the cylinder 26;

31 is a pulse motor that rotationally drives the camshaft 30 on which the first cam 15 and the second cam 25 are provided, and 32 is a courtesy detection disk provided on the camshaft 30 and provided with a notch for detecting the origin. be.

40 is a liquid chromatograph device, 41 is an injector that collects a certain amount of sample, 42 is a column that chromatographically separates the 791 constant component in the sample, and 43 is column 4.
This is a detector that detects the measurement components separated in step 2.

50 is a motor control unit that controls the motor 31 according to the operating state of the pump 10 and the damper 20; 51 is an origin detection unit that detects a notch in the origin detection disk 32 using, for example, light; A pressure detection means 53 detects the pressure of the liquid in the reference section (for example, the discharge valve 1
9 is a storage means for storing the pressure in the section where the pressure is stable before closing), and 54 is a comparison means for comparing the pressure in the reference section stored in the storage means 53 with the current pressure.

Next, the operation of the above configuration will be explained. For example, if the pulse motor 31 is driven at a pulse interval T' (μsec) and rotates at a constant speed, ideally the damper 20
From this, a so-called pulseless flow of liquid with a smooth pressure cover as shown in FIG. 9 should be discharged. However, in reality, due to liquid compression, liquid leakage from the suction valve 18 and discharge valve 19, etc., a pressure dip, which is a negative peak, as shown in FIG. 10, occurs, for example. In order to avoid such a pressure dip, the pressure Po in the reference section (the pressure in section A in FIG. 10) is compared with the pressure in other sections by the comparison means 54, and the detected pressure is the pressure P. If it becomes lower than
The motor control means 50 increases the speed of the pulse motor 31 to avoid a pressure dip.

(Problem to be Solved by the Invention) In the conventional example of the above configuration, the liquid chromatograph device 4
It also reacts to large pressure changes due to other reasons, such as sudden changes in back pressure due to switching of the 0 column 42, and instead causes an increase in pulsation and flow rate fluctuations, and in this case, an excessive load is also placed on the pulse motor 31. There is a problem.

Furthermore, since the pressure signal obtained by the pressure detection means 52 contains noise, it is necessary to make a judgment at a level higher than the noise level in order to judge whether the pressure has decreased or increased. Further, after detecting a change in pressure, a time delay occurs until the speed actually starts to increase or until the speed increases or stops. Therefore, there is a problem in that sharp pressure fluctuations as shown in FIG. 11 occur.

The present invention has been made in view of the above-mentioned problems, and its object is to provide a liquid transfer device that can reliably and accurately transfer liquid without pulses under any back pressure or flow rate.

(Means for Solving the Problems) The present invention for solving the above problems includes a camshaft including a first cam, a second cam, and an origin detection disk, and a camshaft that is driven by the first cam, A pump that discharges liquid, a damper that is driven by the second cam, sucks liquid discharged from the pump, and discharges the sucked liquid when the pump does not discharge liquid, and rotationally drives the camshaft. a drive section, an origin detection means for detecting the origin of the origin detection disk, a pressure detection means for detecting the pressure of the liquid discharged from the damper, and receiving signals from the origin detection section and the pressure detection section. a gate means for outputting the pressure in the reference section at a speed increase, a speed increase pattern calculation means for calculating a speed increase pattern in advance from at least the speed increase end angle; a storage means in which a speed end angle, a speed increase coefficient, and a speed increase start angle are stored; and a calculation means for calculating an actual speed increase end angle by taking in the signal from the gate means and the data in the storage means. , and control means for controlling the drive unit by taking in signals from the calculation means.

(Function) In the liquid feeding device of the present invention, the camshaft including the first cam, the second cam, and the origin detection disk is rotationally driven by the drive section. The first cam and the second cam drive a pump that sucks in and discharges liquid, and a damper that sucks a portion of the liquid discharged from the pump and discharges the sucked liquid when the pump does not discharge liquid. be done. The gate means takes in signals from an origin detection section that detects the origin of the origin detection disk section and a pressure detection means that detects the pressure of the liquid discharged from the damper, and outputs the pressure in the reference section. Then, using the speed increase pattern calculation means,
Find the optimal speed increase pattern in advance. The calculation means receives the signal from the gate means and the data stored in the storage means in which the optimum speed increase pattern, speed increase end angle, speed increase coefficient, and speed increase start angle determined by the speed increase end angle calculation means are stored. and calculate the speed increase end angle. The control means receives a signal from the calculation means and controls the drive section.

(Example) Next, one embodiment of the present invention will be described using the drawings.

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing the relationship between the compression ratio of the liquid and the end angle of speed increase, and Fig. 3 explains the operation of the end angle of speed increase calculation means. flow diagram,
FIG. 4 is a diagram explaining the pressure drop in this example,
Figure 5 is a diagram explaining the relationship between speed increase end angle and pressure, Figure 6 is a diagram explaining the time interval of pulses applied to the stepping motor in Figure 4, and Figure 7 is the flowchart shown in Figure 3. It is a figure explaining the next flow in .

First, in FIG. 1, 90 is a camshaft consisting of a first cam 75°, a second cam 85, and an origin detection 92.

61 is a tank in which eluent is stored, for example, 62 is a tank in which discharged liquid such as eluent is stored, and 70 is tank 61
71 is a plunger; 72 is a spring that provides restoring force to the plunger 71;
73 is a piston connected to the plunger 71; 74 is a wheel provided on the end surface of the piston 73 on the side opposite to the plunger;
6 is a cylinder in which the plunger 71 moves in and out to discharge/inhale liquid; 77 is a sealing material that seals the cylinder 76; 78 is a suction valve that opens when liquid is sucked into the cylinder 76; 79 is a cylinder that discharges liquid from the cylinder 76; This is a discharge valve that opens when the gas is discharged.

80 is a damper that discharges the liquid that has been sucked when the pump 70 is suctioning and provides a non-pulsating liquid flow, 81 is a plunger, 82 is a spring that provides restoring force to the plunger 81, and 83 is a piston connected to the plunger 81. , 84 is a wheel provided on the opposite end surface of the piston 83, 86 is a cylinder into which the plunger 81 moves in and out to discharge/inhale liquid, and 87 is a sealing material for sealing the cylinder 86.

91 is a pulse motor that rotationally drives the camshaft 90. Furthermore, the origin detection disk 92 of the camshaft 90
is provided with a notch for detecting the origin.

100 is a liquid chromatography device, 101 is an injector that collects a certain amount of sample, 102 is a column that chromatographically separates the n1 constant component in the sample, and 103 is a detector that detects the component to be measured separated by column 102. .

110 is a control means for controlling the motor 91 according to the operating state of the pump 70 and the damper 80; 111 is an origin detection means for detecting a notch in the origin detection disk 92 using, for example, light; and 112 is a liquid supplied from the damper 80. A pressure detecting means 113 for detecting the pressure of the liquid is a gate means that receives signals from the origin detecting means 111 and the pressure detecting means 112 and outputs the pressure in the reference section. Reference numeral 116 denotes a speed increase pattern calculation means that changes the speed increase end angle and obtains in advance the optimum speed increase end angle and speed increase pattern of the liquid to be measured at the pressure in the reference section. 114 is a storage means in which the speed increase end angle, speed increase pattern, speed increase coefficient, and speed increase start angle obtained by the speed increase end angle calculation means 116 are stored;
115 is a signal from gate means 113 and storage means 114;
This calculation means takes in the data of , calculates the speed increase end angle, and outputs the calculation result to the control means 110.

Next, the operation of the above configuration will be explained. First, using the speed increase end angle calculating means 116, the speed increase end angle at the pressure in the reference section of the liquid to be measured is set. As shown in FIG. 2, the speed increase end angle of the 11) J constant liquid is between water, which has a small compressibility, and hexane, which has a large compressibility.

Therefore, as shown in FIG. 3, first, press the pressure correction key provided on the console (step 1). Next, the pump 70 is operated at the speed increase end angle of hexane at the pressure at which the pump 70 is operating (step 2). At this time, check the ripple 1 (pressure profile) (step 3).

Next, the pump 70 is operated at the speed increase end angle of the water at the pressure at which the pump 70 is operating (step 4). Examine ripple 2 (pressure profile) at this time (step 5
). The speed increase end angle of the liquid to be measured is determined from ripple 1 and ripple 2 (step 6). Then, the ripple at the calculated acceleration end angle is checked (step 7). The speed increase end angle is changed little by little to find the speed increase end angle that yields the best ripple (step 8). A speed increase pattern of the liquid to be measured is calculated (step 9). The speed increase end angle at the reference pressure is displayed (step 10). Finally, the determined speed increase end angle and speed increase pattern are stored in the storage means 114 (step 11).

By the way, as shown in FIG. 4, when the camshaft 90 rotates at a constant speed, the discharge flow rate E (shaded area) on the pump 70 side between the rotation angles α1 and α2 of the camshaft 90 (after the reference section) ) is a portion where the liquid is not discharged from the liquid feeding device because the liquid is compressed or the liquid flows backward from the discharge valve 79 or the like, and the rising of the discharge speed of the pump 70 is delayed. Therefore, the flow rate discharged from the liquid feeding device is as shown by C (indicated by a dashed line). Therefore, in order to compensate for this drop in flow rate, it is necessary to increase the speed in the drop region. However, as shown in FIG. 5, if the speed is increased too much, the pressure increases, so in this embodiment, the following operation is performed.

Control means 110 drives pulse motor 91 at a constant speed.

The pressure Px in the reference section is taken into the calculation means 115 using the pressure detection means 112 and the gate means 113.

As shown in FIG. 6, the control means 110 operates from the acceleration start angle α stored in the storage means 114 to the acceleration end angle α2 determined in advance according to the acceleration pattern stored in the storage means 114. , increase the speed of the pulse motor 91 and change the pulse time interval to T-*T-b/a.
; b/a is the acceleration coefficient), which compensates for the drop in flow rate.

Furthermore, when using the same liquid to be measured next time, as shown in Fig. 7, by inputting the previously displayed speed increase end angle into the console (step 12), the optimum speed increase pattern can be determined. The calculation means 116 calculates (step 13) and stores the obtained speed increase pattern in the storage means 114 (step 14), thereby making it possible to operate the pump 10 under optimal conditions.

According to such a configuration, since the time interval which is the speed increase is fixed, even if there is a sudden pressure fluctuation, an excessive load is not placed on the pulse motor 9].

In addition, since the control of this embodiment does not capture and control pressure changes, it is necessary to judge at a level higher than the noise level in order to judge a decrease/increase in pressure as in the conventional case. There is no problem in that there is a time delay between when a change in speed is detected and when the speed actually starts to increase or when the speed increases or stops.

Note that the present invention is not limited to the above embodiments.

In the above embodiment, the speed increase pattern calculating means 116 calculates the end angle of speed increase of the liquid to be measured, but if it calculates the compression ratio of the liquid to be measured and calculates the speed increase pattern based on this, The acceleration pattern can be calculated by investigating the compressibility of the liquid to be measured from literature and applying it manually.

(Effects of the Invention) As described above, according to the present invention, liquid can be reliably and accurately and pulselessly fed under any back pressure or flow rate, and further,
It is possible to realize a liquid feeding device that can perform pulseless liquid feeding under any back pressure change or flow rate change.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing the relationship between the compression ratio of the liquid and the end angle of speed increase, and Fig. 3 explains the operation of the end angle of speed increase calculation means. flow diagram,
FIG. 4 is a diagram explaining the pressure drop in this example,
Figure 5 is a diagram explaining the relationship between speed increase end angle and pressure, Figure 6 is a diagram explaining the time interval of pulses applied to the stepping motor in Figure 4, and Figure 7 is the flowchart shown in Figure 3. 8 is a diagram explaining the following flow, FIG. 8 is a configuration diagram of a conventional liquid feeding device, FIGS. 9 and 10 are diagrams explaining the control in FIG. 8, and FIG. 11 is a diagram explaining the problems in FIG. 8. FIG. In these figures, 10.70... Pump 15,75... First cam 20.80... Damper 25.85... Second cam 31.91... Pulse motor 40.100 ...Liquid chromatograph device 50...
Motor control means 51.111... Origin detection means 52.112... Pressure detection means 53.114... Storage means 54... Comparison means 90... Camshaft 6
2... Origin detection disk 110... Motor control means 113... Gate means 115... fi calculation means 1
16... Speed increase pattern calculation means Fig. 2

Claims (1)

[Claims] A camshaft including a first cam, a second cam, and an origin detection disk; a pump driven by the first cam and sucking and discharging liquid; and the second cam. a damper that is driven to suck liquid discharged from the pump and discharge the sucked liquid when the pump does not discharge liquid; a drive unit that rotationally drives the camshaft; and a drive unit that rotates the camshaft and detects the origin of the origin detection disk. a pressure detection means for detecting the pressure of the liquid discharged from the damper; and a gate means for taking in signals from the origin detection section and the pressure detection section and outputting the pressure in the reference section; A speed increase pattern calculation means for calculating a speed increase pattern in advance from at least a speed increase end angle, a speed increase pattern calculated by the speed increase end pattern calculation means, a speed increase end angle, a speed increase coefficient, and a speed increase start angle. storage means in which is stored; calculation means for calculating an actual acceleration end angle by taking in the signal from the gate means and the data in the storage means; and calculation means for taking in the signal from the calculation means, A liquid feeding device comprising: a control means for controlling the driving section.