JP2662382B2 - Liquid metering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid dispensing apparatus capable of precisely dispensing a liquid containing a viscous fluid such as an adhesive or various paste-like materials, and more particularly to a liquid dispensing apparatus having a single apparatus main body. The same or different liquids can be discharged from each of the plurality of discharge heads accurately and quantitatively in accordance with a predetermined amount unique to each of the plurality of discharge heads.

[0002]

2. Description of the Related Art A conventional liquid dispensing apparatus of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 2-184370 by the present applicant. FIG. 2 is a circuit diagram showing the discharge device, in which a syringe 2 filled with liquid 1 is a discharge electromagnetic switching valve 3 which can be a three-port two-position valve.
Port A of the discharge electromagnetic switching valve 3 is connected to an air supply source 7 via a pressure reducing valve 6 by a second pipe 5. In addition, an accumulator 8 is provided in the second pipe 5 at an intermediate position between the discharge electromagnetic switching valve 3 and the pressure reducing valve 6.

Here, the discharge electromagnetic switching valve 3 causes communication between the port A and the outflow port R when a voltage signal as a shift signal is not supplied thereto. To communicate with the inflow port P.

In this device, a suction electromagnetic switching valve 10 which can be a two-port two-position valve is connected to an outlet port R of the discharge electromagnetic switching valve 3 by a third pipe 9.
An air suction source 12 is connected to the outflow port B of the suction electromagnetic switching valve 10 by a fourth pipe 11, and the third pipe 9 is a two-port two-position valve. An air-opening electromagnetic switching valve 13 is connected, and an accumulator 14 is connected to the fourth pipe 11.

[0005] Here, these electromagnetic switching valves 10 and 13 are both opened when a voltage signal is supplied, and are closed when the supply of the voltage signal is stopped.

[0006] In addition, here, the first pipe 4 and
At a position downstream of the accumulator 8 of the second pipe 5,
First and second pressure sensors 17, 18 are respectively connected via respective pipes 15, 16, and these pressure sensors 17, 18 detect the internal pressure of the respective pipes 4, 5, and Converts the detected pressure to an electric signal and converts each
Functions to input to 19 and 20.

By the way, each conversion circuit 19, 20
An amplification circuit 21 that amplifies weak output signals from the pressure sensors 17 and 18 and calibrates variations in the output signals.
And an A / D converter 22 for converting an analog signal into a binary digital signal. Output signals from the respective conversion circuits 19 and 20 are provided by a microprocessor,
Control unit 23, which can be a one-chip computer or the like
Is input to

The control unit 23 functions to output a voltage signal 41 to the discharge electromagnetic switching valve 3 when the discharge start signal 40 is input thereto, and for example, after the supply of the voltage signal 41 is stopped, Normally, it functions to sequentially output voltage signals 42 and 43 to the electromagnetic switching valve 13 for opening to the atmosphere and the electromagnetic switching valve 10 for suction. Here, each of the voltage signals 41, 42, and 43 is amplified by the voltage amplifier circuits 24, 25, and 26, and then input to the respective electromagnetic switching valves 3, 13, and 10.

[0009] Such a control unit itself includes:
A setting switch 23a for setting time, condition, and the like, and a setting data display section 23b are provided. Here, the setting switch 23a is provided with a switch for setting the opening time of the discharge electromagnetic switching valve 3 necessary for discharging a predetermined amount of the liquid 1, and a first switch when the liquid remaining amount in the syringe changes. A switch for setting a numerical value for increasing or decreasing the discharge time in accordance with a change in the rise of the pressure measured by the pressure sensor 17, and a switch for setting the respective opening times of the electromagnetic switching valve 10 for suction and the electromagnetic switching valve 13 for opening to atmosphere. And a switch for setting a required negative pressure value in the space 30 including the space on the upper surface of the liquid 1 in the syringe and the spaces in the pipes 4 and 15.

In order to simplify the following description, here, the electromagnetic switching valve 3 for discharge and the pressure reducing valve 6 in the second pipe 5 are described.
, The space in the accumulator 8, and the pipe 16
The space 31 includes the space within the third pipe 9 and the space 32 includes the space within the pipe from the pipe 9 to the electromagnetic switching valve 13 for opening to the atmosphere. Further, the setting data display section 23b includes, in addition to the data display sections such as time and conditions set by the setting switch 23a, the respective spaces 30 and 30 detected by the respective pressure sensors 17 and 18.
Equipped with 31 pressure display.

The operation of the device configured as described above is as follows. Normally, the discharge electromagnetic switching valve 3 is connected to the port A
And the outlet port R, the pressure in the space 30 is maintained at the same pressure as the pressure in the space 32.
The pressure of 31 is controlled by the pressurized air from the air supply source 7
The pressure is adjusted by the pressure reducing valve 6 based on a control signal from the controller to the pressure reducing valve 6, so that the predetermined value is maintained according to the syringe volume, the type of liquid in the syringe, and the like.

At this time, the pressures in the respective spaces 30, 31 are detected by the respective pressure sensors 17, 18, and displayed on the setting data display section 23b.

In this state, when the discharge start signal 40 is input to the control section 23, the control section 23 outputs the electromagnetic switching valve 3 for discharge.
A voltage signal 41 is output to the port, and communication between the port A of the electromagnetic switching valve 3 for discharge and the inflow port P is brought about. As a result, the internal pressure of the space 31 is supplied to the space 30.
Discharge of the liquid 1 in the syringe is started.

By the way, the time during which the internal pressure of the space 30 becomes equal to that of the space 31 changes, for example, as shown by curves a, b, and c in FIG. 3 due to a change in the remaining amount of the liquid 1 in the syringe. In order to always discharge a constant amount of liquid from the syringe 2, it is necessary to control the voltage signal output time from the control unit to the discharge electromagnetic switching valve 3 in consideration of such a time difference.

In FIG. 3, a curve a represents a first pressure sensor when the liquid 1 is fully filled in the syringe.
17 shows an ideal rising curve of the measured pressure according to 17, and curves b and c show similar rising curves when the remaining amount of the liquid in the syringe decreases by a fixed amount, respectively.

In the figure, DT is a preset discharge time for detecting the amount of liquid remaining in the syringe, in other words, a preset output time of the voltage signal 41.

Therefore, here, first, the integral value of each of the curves a, b, and c within the preset discharge time DT, specifically, the unit time of each of the curves a, b, and c The remaining amount of the liquid 1 in the syringe is detected by obtaining the accumulated value of the measured pressures by the control unit 23.

That is, as can be seen from the hatched portions in FIG. 4, the respective integral values of the curves a, b, and c become smaller as the amount of liquid remaining in the syringe becomes smaller. Is calculated based on the relative relationship between the remaining liquid amount and the integral value previously input to the control unit 23, and the remaining liquid amount in the syringe is detected each time the liquid 1 is discharged. I can do it. Therefore, the integral value or the remaining liquid amount in the case where the remaining amount of the liquid is reduced to the extent that the syringe needs to be replaced is also input in advance to the control unit 23, so that the remaining amount of the liquid in the syringe becomes the input value. It can be easily informed by the display on the setting data display unit 23b, the generation of an alarm, and the like that the power consumption has been reduced.

Thereafter, the output time of the voltage signal to the electromagnetic switching valve 3 for discharge is set based on the change in the integral value as described above due to the change in the amount of liquid remaining in the syringe. The discharge amount of the liquid 1 from the syringe 2 is
Irrespective of the amount of liquid remaining in the syringe, constant leveling with high accuracy is possible.

On the other hand, after a predetermined output time of the voltage signal 41 elapses, the supply of the voltage signal 41 to the discharge electromagnetic switching valve 3 is stopped, and the voltage signal 41 is discharged from the port A of the discharge electromagnetic switching valve 3 to the outlet A. Communication with port R, and thus space 30 and space 32
And the internal pressure of the syringe 2 decreases,
The discharge of the liquid 1 ends.

Here, in order to stop the discharge of the liquid 1 simultaneously with the stop of the output of the voltage signal 41, it is necessary to instantaneously reduce the internal pressure of the space 30 to at least the atmospheric pressure. At the same time as or slightly earlier than the stop of the output of the voltage signal 41, the controller 23 outputs the voltage signal 42 from the control unit 23 to the atmosphere-opening electromagnetic switching valve 13 to switch the switching valve.
By setting the port 13 to the atmosphere open state, the internal pressure of the space 30 and thus the syringe 2 can be quickly returned to the atmospheric pressure after the communication between the port A and the outlet port R of the electromagnetic switching valve 3 for discharge.

The same effect can also be obtained by opening the electromagnetic switching valve 10 for suction at the same timing as that described above for the electromagnetic switching valve 13 for opening to the atmosphere. However, in this case, the introduction time of the negative pressure into the space 32 is longer than the above case mainly due to the pipe resistance. Therefore, in order to reduce the cycle time from the discharge of the liquid 1 to the discharge, It is particularly effective to operate the air release electromagnetic switching valve 13 as described above.

On the other hand, when the cycle time is relatively long, the suction electromagnetic switching valve 10 is opened after the atmosphere opening electromagnetic switching valve 13 is closed, or the atmosphere opening electromagnetic switching valve 13 is closed. Without opening, at the same time as the stop of the output of the voltage signal 41 or at a slightly earlier timing, the suction electromagnetic switching valve 10 is opened, so that the space 32, and thus the space 30, is at a predetermined negative pressure, Leakage of the liquid 1 from the tip of the syringe 2 is reliably prevented.

Here, when the negative pressure measured by the first pressure sensor 17 reaches a predetermined value, the suction electromagnetic switching valve 10 is closed based on the stoppage of the supply of the voltage signal 43 thereto. .

Note that the predetermined negative pressure value also changes according to the amount of liquid remaining in the syringe, so that the controller 23 determines the amount of remaining liquid based on the above-described detection result.
By controlling the output time of the voltage signal 43 to the suction electromagnetic switching valve 10 and setting the predetermined negative pressure to a pressure corresponding to the weight of the remaining liquid, leakage of the liquid can be efficiently prevented. .

[0026]

As is apparent from the above description, according to the prior art proposed by the applicant, regardless of the amount of liquid remaining in each syringe, A constant amount of liquid can be constantly dispensed with high accuracy, and a negative pressure corresponding to the remaining amount of liquid in the syringe
By supplying the syringe, unexpected liquid leakage can be effectively prevented.

However, since this device is intended only for one syringe, in other words, only for a fixed amount of discharge from one discharge head, it is possible to use a plurality of devices having different discharge amounts and different types of discharge materials. When performing a fixed amount discharge of a liquid such as an adhesive or a conductive paste from the respective discharge heads sequentially or selectively by using the discharge heads, prepare the same number of device bodies as the discharge heads Is necessary, there is a structural and cost problem that the whole apparatus becomes remarkably large and large.Moreover, various data such as a discharge timing, a discharge time, a negative pressure suction time, etc. However, there is a trouble in the input operation that the setting must be performed separately without causing interference between the ejection heads.

The present invention advantageously solves the above-mentioned problems of the prior art, and enables a plurality of ejection heads to be properly operated in a required order with a single apparatus main body so that a required liquid material can be obtained. In addition to being able to perform quantitative discharge with high precision at the expected discharge amount, the entire device can be sufficiently miniaturized, and by switching the discharge head and the corresponding channel, various types of discharge heads can be used. Provided is a liquid dispensing apparatus capable of easily and easily inputting data and effectively preventing unexpected leakage of liquid in a syringe due to leakage of negative pressure in the syringe. It is intended for.

[0029]

Therefore, the present invention is based on one apparatus main body described in the prior art, and includes a control system and a required number of ejection heads, in other words, a syringe. In addition to the working portion including, the addition of a negative pressure bypass passage and the like is intended to achieve the above object, the liquid metering device of the present invention,
A plurality of syringes for discharging the filled liquid are provided, and an air supply source for supplying pressurized air to each of the syringes and an air suction source for applying a negative pressure are provided. One discharge electromagnetic switching valve that connects each of the corresponding syringe selecting electromagnetic switching valves and selectively communicates either the air supply source or the air suction source with the syringe selecting electromagnetic switching valves. And a pressure sensor is provided between the discharge electromagnetic switching valve and each of the syringe selection electromagnetic switching valves, and a suction electromagnetic switching is provided between the discharge electromagnetic switching valve and the air suction source. A valve is provided to output a discharge signal and a suction signal to each of the electromagnetic switching valve for discharge and the electromagnetic switching valve for suction, and to each of the electromagnetic switching valves for syringe selection. A control unit for outputting a syringe selection signal, the control unit connecting a syringe switching signal input unit and a data memory channel switching unit, and a data memory unit, respectively; And an air suction source are connected by a bypass passage, and a single suction repetition solenoid switching valve is provided in the bypass passage, and the suction repetition solenoid switching valve is connected to the suction repetition solenoid switching valve at predetermined time intervals for a predetermined period of time. A controller to be activated is connected.

Here, preferably, a pressure reducing valve connected to the control unit is provided between at least one of the air supply source and the discharge electromagnetic switching valve and between at least one of the air suction source and the suction electromagnetic switching valve. I do.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic operation of the apparatus main part of this liquid dispensing apparatus is performed in substantially the same manner as described in the prior art, and the liquid dispensing from one of the discharge heads, ie, one syringe, is performed. The discharge is performed based on the input of the switching signal from the syringe switching signal input means to the control unit, and the output signal from the control unit activates one syringe selection electromagnetic switching valve corresponding to the required syringe, and controls the discharge. The discharge is started by input of a discharge signal from the section to the electromagnetic switching valve for discharge, and the discharge is performed according to the discharge data specific to the required syringe stored in a specific channel of the data memory section having a channel corresponding to the number of syringes. , For a predetermined time.

On the other hand, the fixed amount discharge is stopped by switching the discharge electromagnetic switching valve prior to the closing operation of the syringe selecting electromagnetic switching valve, and in relation to the operation time of the suction electromagnetic switching valve, the inside of the syringe is switched. Is set to a degree of negative pressure sufficient to offset the weight of the remaining liquid therein, and thereafter, the syringe selector solenoid-operated directional control valve is closed, and a predetermined amount contributing to the prevention of leakage of the remaining liquid into the syringe. This is done by enclosing a negative pressure.

After the fixed amount discharge by one syringe is completed in this way, the same or another syringe is supplied to the same or another syringe by the subsequent input of the switching signal from the syringe switching signal input means to the control unit. The same fixed amount discharge is performed.

In the case where such a discharge operation is repeatedly performed for each syringe, if the required discharge amount from one syringe differs according to the discharge position, each of the corresponding channels of the data memory unit is This can be dealt with by reading the ejection data input in advance at the address of the above according to the ejection position.

When a required amount of liquid is ejected from a single syringe a plurality of times in the data memory section based on, for example, ejection time data, if only the ejection time data is used, the syringe is used. Since the actual liquid discharge amount also fluctuates due to the change in the remaining liquid amount in the inside, here, in order to effectively prevent such fluctuation, the measurement of the syringe internal pressure by the pressure sensor is performed as described in the related art. The value is integrated over a certain period of time from the operation of the discharge electromagnetic switching valve, and the discharge time data is corrected based on the change in the integrated value, thereby correcting the discharge signal output time to the discharge electromagnetic switching valve. Lengthen by a minute.

In operating the liquid metering apparatus in the manner described above, here, the data memory channel switching means connected to the control unit is used to correspond to each syringe of the data memory unit also connected to the control unit. Select the desired one of each channel you want to
The channel is provided with a time / condition setting switch to set the discharge data of the corresponding syringe, in other words, the discharge time as the opening time of the discharge electromagnetic switching valve, and the internal pressure of the syringe caused by the change in the residual liquid amount in the syringe. The discharge time correction value accompanying the change of the integral value, the opening time of the electromagnetic switching valve for suction, the correction value of the opening time in consideration of the remaining liquid amount, and the like are stored in advance, and the same is performed for all other channels. Is sequentially repeated.

Here, when the ejection amount of the same syringe differs depending on the ejection position, each address is set in the corresponding channel, and the above-described ejection data is stored for each address.

The ejection data of each channel stored in the data memory unit in this manner is supplied to a required syringe, directly to a syringe selection electromagnetic wave, by the input of the switching signal from the syringe switching signal input means to the control unit. Simultaneously with the selection of the switching valve, the reading is performed from the corresponding channel, and thereafter, the operation of each electromagnetic switching valve is controlled based on the discharge data.

Accordingly, in this case, a plurality of syringes filled with the same or different liquids can always be properly discharged in a required order by using one apparatus main body, and the entire apparatus can be significantly simplified. In addition to being able to reduce the size, the input of the discharge data can be made extremely easy under the action of one control unit. In addition, this device can accurately detect the amount of liquid remaining in the syringe and perform high-precision quantitative discharge, and perform high-precision negative pressure suction without excess or shortage.

Further, according to this device, a bypass passage is provided for connecting the syringe selecting electromagnetic switching valve and the air suction source, and the bypass passage is operated by the controller at predetermined time intervals for a predetermined time. By providing an electromagnetic switching valve for repetition of suction, each syringe that is continuously inactive for a relatively long time can be suctioned from each of the electromagnetic valves for selecting a syringe without passing through the electromagnetic switching valve for discharge. By simultaneously connecting to the air suction source via the repetition electromagnetic switching valve, it is possible to compensate for leakage of negative pressure from the inactive syringe and effectively prevent leakage of liquid in the syringe, On the other hand, a passage that passes through the discharge electromagnetic switching valve can be used for constant discharge of liquid from any one of the syringes.

Here, at least one of the pressure reducing valves controlled by the control unit is provided between at least one of the air supply source and the discharge electromagnetic switching valve and between the air suction source and the suction electromagnetic switching valve. In the case where the discharge pressure and / or suction negative pressure supplied to each syringe is adjusted according to the amount of liquid remaining in each syringe, the precision of quantitative discharge of liquid and / or the suction precision of negative pressure is adjusted. Can be further increased.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment of the present invention, in which parts similar to those described in the prior art are designated by the same reference numerals.

That is, in the figure, 3 is a discharge electromagnetic switching valve which can be a three-port two-position valve, 6 is a pressure reducing valve,
7, an air supply source; 8, an accumulator disposed between the discharge electromagnetic switching valve 3 and the pressure reducing valve 6;
Reference numeral 10 denotes a suction electromagnetic switching valve which can be a two-port two-position valve connected to the discharge electromagnetic switching valve 3, reference numeral 12 denotes an air suction source, and reference numeral 14 denotes a switching between the air suction source 12 and the suction electromagnetic switching valve. Valve 10
And the accumulators disposed between them.

Reference numeral 13 denotes an atmosphere opening electromagnetic switching valve connected between the discharge electromagnetic switching valve 3 and the suction electromagnetic switching valve 10, and reference numeral 17 is connected downstream of the discharge electromagnetic switching valve 3. In addition, a pressure sensor for detecting an internal pressure of each syringe described later is shown. Reference numeral 18 denotes another pressure sensor connected upstream of the discharge electromagnetic switching valve 3.

Further, reference numerals 19 and 20 denote respective conversion circuits,
Reference numeral 23 denotes a control unit, and reference numeral 23a denotes a control unit 23,
Further, a time / condition setting switch for a data memory unit to be described later is set, and a setting data display unit 23b for displaying data set by the setting switch 23a.

Here, each of the electromagnetic switching valves 3, 10, 13
Functions to operate for a predetermined time at a predetermined timing based on a command from the control valve 23, as in the case of the prior art, and the pressure reducing valve 6 also increases the supply pressure based on a command from the control unit 23. Works to adjust as needed.

In this embodiment, in the pneumatic circuit, a required number of syringes 51 are connected to the discharge electromagnetic switching valve 3 via a branch pipe, and each of the syringes 51 and the discharge electromagnetic switching valve 3 are connected. 3 are connected to the respective syringes 51 and the corresponding solenoid-selecting solenoid-operated directional control valves 52,
Here, a two-port two-position valve is provided, and a pressure reducing valve 53 connected to the control unit 23 is interposed between the air suction source 12 and the accumulator 14.

Here, each syringe 51 is
The same or different types of liquids filled therein function to discharge in accordance with the discharge data described later. Each of the syringe selecting solenoid-operated directional control valves 52 includes a control unit.
Based on a command from 23, the corresponding syringe 51 functions to selectively communicate with the discharge electromagnetic switching valve 3. And the pressure reducing valve 53 is also based on a command from the control unit 23,
It functions to adjust the negative pressure supplied to the syringe 51 via the discharge electromagnetic switching valve 3 to a magnitude just matching the remaining liquid amount in the syringe.

In this embodiment, a syringe switching switch 54 as a syringe switching signal input means and a data memory channel switching switch 55 as data memory channel switching means are connected to the control section 23, respectively. Connect.

Here, the syringe switching switch 54 includes a control unit
From 23 via the syringe selection electromagnetic switching valve drive circuit 57,
The switching operation of the required one syringe selecting electromagnetic switching valve 52 is provided, and in synchronization with the switching operation, a data memory unit is provided.
From 56, the changeover valve 52, and thus the syringe 51, functions to read the ejection data stored in the channel corresponding to the data memory channel changeover switch 55, when storing the ejection data, the data memory unit 56,
Functions to select a channel corresponding to the syringe 51. Then, as described above, the time / condition setting switch 23 is set for the channel selected in this manner.
a, the discharge time inherent to the syringe 51, the discharge time correction value based on the change in the integral value of the syringe internal pressure caused by the change in the residual liquid amount in the syringe, the suction electromagnetic switching valve 10
, An opening time correction value in consideration of the remaining liquid amount, more preferably, in addition thereto, an adjustment pressure value by the pressure reducing valves 6 and 53 and other ejection data.

Therefore, all the ejection data are stored in the data memory section 56 by selecting the channel corresponding to each syringe 51 in the data memory section 56 by the data memory channel changeover switch 55.
The required ejection data as described above is input, and this is completed by performing the necessary sequential operations for all the syringes.

When the required discharge amount for one syringe 51 differs depending on the discharge position, an address corresponding to the number of discharge positions is set in a memory channel corresponding to the syringe 51, and each address is set. The required ejection data is stored in the memory.

By the way, the syringe switching signal input means and the data memory channel switching means connected to the control unit 23 are respectively provided with the respective switches 54 and
Instead of, or in addition to, an external input signal 58
And 59 are also possible. Also, here, in order to more effectively prevent leakage of liquid from the syringe that may be inoperative for a relatively long time, each of the syringe selection electromagnetic switching valves 52 is a three-port two-position valve. And a solenoid-operated switching valve for each of those syringes.
52 is connected to the air suction source 12 by the bypass passage 60,
An electromagnetic switching valve 62 for repetition of suction connected to a controller 61 is provided in the bypass passage 60. Here, the controller 61 includes a time setting unit 63 and a control means 64, and functions to operate the electromagnetic switching valve 62 for repeating suction at predetermined time intervals for a predetermined time.

Here, each of the syringe selecting solenoid-operated switching valves 52 functions to connect the syringe 51 to the bypass passage 60 when it is not operated, so that each of the syringes 51 in this example has a discharge operation. After the internal pressure is reduced to a predetermined internal negative pressure, the state of communication with the bypass passage 60 waits for the next operation.

An example of the operation of the device configured as described above will be described below. At the start of the quantitative dispensing work,
First, the syringe changeover switch 54 selects a predetermined syringe 51 for first performing a fixed amount discharge, thereby switching and operating the syringe 51 and the corresponding syringe selection electromagnetic switching valve 52. From the channel corresponding to the syringe 51, predetermined ejection data stored in advance is read out, and then the ejection start signal 40 as an external input signal, waiting for input to the control unit 23,
The air supply system is operated based on the discharge data, and pressurized air from the air supply source 7 is supplied to the syringe 51 under the operation of the discharge electromagnetic switching valve 3.

Here, the actual supply time of the air to the syringe 51, in other words, the actual discharge time, is read from the memory channel when, for example, the remaining liquid amount in the syringe remains at the time of liquid filling. Discharge time itself, which enables high-precision quantitative discharge. On the other hand, when there is a decrease in the amount of liquid remaining in the syringe, based on the integration result of the measured value of the internal pressure of the syringe over a certain period of time by the pressure sensor 17,
By correcting the actual discharge time in consideration of the discharge time correction, the quantitative discharge accuracy is maintained as expected. In this case, by adjusting not only the discharge time but also the supply pressure by the pressure reducing valve 6, the quantitative discharge accuracy can be further improved.

After one fixed amount of discharge is performed by one syringe 51 in this manner, the electromagnetic switching valve 3 for suction is returned to the original position, so that the electromagnetic switching valve 10 for suction is returned simultaneously with its return. Alternatively, under a switching operation somewhat earlier than its return, a negative pressure from the air suction source is applied to the syringe for a predetermined time, thereby offsetting the liquid weight in the syringe with the negative pressure. . Here, when the liquid weights are properly offset, it is possible to sufficiently prevent the leakage of the liquid and also sufficiently prevent the suction of air into the syringe.

In the case where the leakage of liquid is prevented by the action of such a negative pressure, the measured negative pressure in the syringe is used here because the proper negative pressure varies depending on the amount of liquid remaining in the syringe. However, the opening time of the electromagnetic switching valve for suction 10 is corrected based on the same integration result as described above, whereby the accuracy of the negative pressure in the syringe is always made appropriate. Also at this time, by adjusting the supply negative pressure using the pressure reducing valve 53, the negative pressure accuracy can be further improved.

After the internal pressure of the syringe is reduced to a predetermined negative pressure by such a series of operations of the pneumatic circuit, the syringe selector 51 and the corresponding syringe selector electromagnetic switching valve 52 are returned to their original positions by a signal from the control unit 23. The discharge operation for one syringe 51 is completed by these operations.

Then, again, the syringe changeover switch
According to 54, the next syringe 51 is selected, and thereafter, the same discharge operation as described above is repeated. Here, the open-to-atmosphere electromagnetic switching valve 13 is particularly effective when the cycle time from one fixed discharge to the next fixed discharge of the specific syringe 51 is short, as described in the related art. is there.

Thus, according to the apparatus of this example, it is possible to sufficiently increase both the precision of quantitative discharge and the precision of suction of negative pressure, and it is also possible to use a single apparatus main body, in other words, a single control system, to perform quantitative measurement from a plurality of syringes. Discharge can be controlled, the overall apparatus can be significantly reduced in size, and the input operation of discharge data can be made extremely easy.

Further, in this embodiment, even if the operation standby time of the syringe 51 is lengthened and the negative pressure is reduced due to the leakage of the negative pressure into the syringe 51, the controller 61 operates under the action of the controller 61. By operating the suction repetition electromagnetic switching valve 62 at predetermined time intervals for a certain period of time, the negative pressure of the air suction source 12 is applied directly to each of the syringes. By compensating for the decrease in the negative pressure, leakage of the filling liquid from any of the syringes can be extremely effectively prevented.

Further, in the case of supplying the negative pressure in this way, no passage other than the bypass passage is required at all, and the function of the pneumatic circuit for the constant discharge is not hindered at all. The selective quantitative discharge by the syringe 51 can be appropriately performed as needed.

[0064]

As is clear from the above description,
ADVANTAGE OF THE INVENTION According to this invention, each of a fixed-quantity discharge precision and a negative pressure suction precision can be sufficiently improved, and the operation control of several syringes can be performed with a very small apparatus. Can be easily and quickly input. In addition, here, by disposing an electromagnetic switching valve for repetition of suction connected to a controller in a bypass passage that provides communication between the electromagnetic switching valve for selecting a syringe and an air suction source, the syringe that is inactive for a long time is provided. Fluid can be prevented very effectively. Here, when a pressure reducing valve connected to the control unit is disposed between the air supply source and the discharge electromagnetic switching valve, the quantitative discharge accuracy can be further improved, and the air suction source and the suction If a pressure reducing valve, which is also connected to the control unit, is provided between the electromagnetic switching valve and the electromagnetic switching valve, the negative pressure suction accuracy can be further improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a conventional example.

FIG. 3 is a graph showing a change in a rising curve of a syringe internal pressure.

FIG. 4 is a comparison diagram showing an integrated value of a measured pressure within a preset time.

[Description of sign]

 3 Discharge solenoid switching valve 6,53 Pressure reducing valve 7 Air supply source 10 Suction solenoid switching valve 12 Air suction source 17 Pressure sensor 23 Control unit 23a Time / condition setting switch 23b Setting data display unit 51 Syringe 52 Syringe selection electromagnetic Changeover valve 54 Syringe changeover switch 55 Data memory channel changeover switch 56 Data memory section 57 Syringe selection electromagnetic switching valve drive circuit 58, 59 External input signal 60 Bypass passage 61 Controller 62 Electromagnetic switching valve for repeated suction

Claims (3)

(57) [Claims] 1. A plurality of syringes (51), an air supply source (7) for supplying pressurized air to each syringe, an air suction source (12) for applying a negative pressure, and respective syringes (51) The solenoid selector valve (52) connected to each of the syringes, and either the air supply source (7) or the air suction source (12) can be selectively connected to the syringe selector solenoid selector valve (52). A discharge electromagnetic switching valve (3) to be communicated with, a pressure sensor (17) disposed between the discharge electromagnetic switching valve and each of the syringe selecting electromagnetic switching valves (52), The discharge signal is supplied to the electromagnetic switching valve for suction (10) disposed between the electromagnetic switching valve (3) and the air suction source (12) and the electromagnetic switching valve for discharging (3), and the electromagnetic switching valve for suction (10 ) And a control unit (23) for outputting a syringe selection signal to each of the syringe selection solenoid-operated switching valves (52). It has a syringe switching signal input means (54) and a data memory channel switching means (55) connected thereto, and a data memory section (56) also connected to the control section (23). Switching valve (52) and air suction source (12)
A bypass passage (60) that provides communication with the suction passage, a single solenoid switching valve for suction repetition provided in the bypass passage, and a valve connected to the solenoid switching valve for suction repetition, which is connected at predetermined time intervals. And a controller (61) for operating the liquid metering device. 2. An air supply source (7) and an electromagnetic switching valve for discharge (3).
2. The apparatus according to claim 1, further comprising a pressure reducing valve (6) connected to the control unit (23). 3. An air suction source (12) and an electromagnetic switching valve (10) for suction.
3. The apparatus according to claim 1, further comprising a pressure reducing valve (53) connected to the control unit (23).