JP2006264755A - Flow meter type liquid filling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow meter type liquid filling apparatus in which a liquid in a pressurized liquid storing tank 1 is at repeatedly filled from through a flow meter 4 outputting a pulse signal at every predetermined flow rate and a valve 5 a filling nozzle 3 to a container and to prevent the variation of the amount of filling even if the pressure in the tank 1 varies. <P>SOLUTION: Filling is started by opening a valve 5 with a valve operating means, the valve 5 is closed when the number of outputted pulse signals reaches to a predetermined number of filling pulses and then the filling at that time is completed. An air pressure within the tank 1 is measured just before starting the filling operation, and the number of filling pulses corresponding to the measured pressure value is calculated in reference to a relation between the air pressure experimentally determined in advance and the number of filling pulses every time one filling operation is carried out. Although the air pressure is varied every time liquid is supplemented from a liquid supplementing tank 6 into the tank 1 when a disinfection filter 23 is connected to the tank 1, a less variation in amout filled occurs because the number of filling pulses is controlled in response to a variation in air pressure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a liquid storage tank pressurized to an atmospheric pressure or more, a filling nozzle that communicates with the liquid storage tank through a liquid conduit, and the discharge of liquid from the filling nozzle installed in the liquid conduit or the filling nozzle and A valve for stopping the valve, a valve operating means for opening and closing the valve, a pressure sensor for measuring a pressure in the liquid storage tank or the liquid pipe, and a flow through the liquid pipe when the valve is open to the filling nozzle The present invention relates to an improvement of a flow meter type liquid filling apparatus including a flow meter that measures a flow rate of a liquid to be sent and outputs a pulse signal at every constant flow rate.

  An example of a conventional flow meter type liquid filling apparatus is shown in FIG. The filling device includes a liquid storage tank 1, a filling nozzle 3 communicating with the liquid storage tank 1 by a liquid pipe 2, a flow meter (for example, an electromagnetic flow meter) 4 and an opening / closing valve 5 installed in the liquid pipe 2, a liquid storage A liquid replenishment tank 6 for replenishing liquid to the tank 1, a liquid level sensor 7 and a pressure sensor 8 installed in the liquid storage tank 1, a pressurized air source for supplying pressurized air to the liquid storage tank 1 and the liquid replenishment tank 6 (Compressor) 9, pressurized air source 9, air pressure adjusting means 10 and 11 installed in the air flow paths of the liquid storage tank 1 and the liquid replenishment tank 6, and the liquid conduit 12 of the liquid storage tank 1 and the liquid replenishment tank 6 And an opening / closing valve 13 and a control device 14.

  The air pressure adjusting means 10 is substantially the same as that described in Patent Document 1, and includes an air supply means 15 and an air discharge means 16, and the air supply means 15 includes the pressurized air source 9 and the liquid storage tank 1. A plurality of air supply passages 17a to 17c installed in parallel, supply passage on-off valves 18a to 18c for opening and closing them, and throttle valves 19a to 19c installed in the air supply passages 17a to 17c. The air discharge means 16 includes a plurality of air discharge passages 20a to 20c that are connected in parallel to the liquid storage tank 1 and one end of which is opened to the atmosphere, discharge passage opening / closing valves 21a to 21c that open and close the air discharge passages, and the air discharge flow. It consists of throttle valves 22a-22c installed in the passages 20a-20c, and the opening degree of the throttle valves 19a-19c, 22a-22c is changed stepwise. On the other hand, the air pressure adjusting means 11 is a general pressure regulating valve (also called a precision regulator).

  The pressure in the liquid storage tank 1 is measured by the pressure sensor 8 and compared with the set pressure (pressure reference value) in the control device 14. When there is a variation from the set pressure, the control device 14 causes the air pressure adjusting means 10 to One or more of the supply flow path opening / closing valves 18a to 18c or the discharge flow path opening / closing valves 21a to 21c are operated to keep the set pressure. At that time, the control device 14 selects a valve to be opened according to the magnitude (variation amount) of fluctuation from the set pressure. That is, when the amount of pressure fluctuation is large, when the valve in the flow path or a plurality of valves in which a throttle valve with a large opening is opened, the pressure in the tank is quickly brought close to the set pressure, and the amount of pressure fluctuation is small Open the valve of the flow path where the throttle valve with a small opening is opened so that it can be adjusted gently, and in any case, the amount of pressure fluctuation in the tank can be reduced and precise control can be performed. It has become.

  The liquid level in the liquid storage tank 1 is measured by the liquid level sensor 7 and compared with the reference level in the control device 14, and when the fluctuation amount (decrease amount) from the reference level exceeds the set value, the control device 14 Sends a control signal to a valve actuating means (not shown) to open the open / close valve 13 and the liquid storage tank 1 is replenished with liquid from the pressurized liquid replenishment tank 6. When the liquid level in the liquid storage tank 1 reaches the reference level, the open / close valve 13 is closed.

This filling apparatus is used in a liquid filling process of an intermittent rotary table type bag filling and packaging machine as described in Patent Document 2, for example. The productivity of this type of bag filling and packaging machine is generally 30 to 50 bags / minute, and the time that can be used for one liquid filling is as short as about 0.4 to 0.7 seconds.
At this time, the filling amount by the filling nozzle 3 is controlled as follows.
(1) When the table of the bag filling and packaging machine rotates intermittently, and the container (bag) held by the gripper at the liquid filling process position stops under the filling nozzle 3, the control device 14 causes the valve operating means (not shown). A control signal is sent to open the on-off valve 5 and supply of liquid from the filling nozzle 3 is started.
(2) At the same time, a pulse signal is sent to the control device 14 every time the flow meter 4 detects a constant flow rate.
(3) When the number of pulse signals output from the flow meter 4 reaches a predetermined number of filling pulses, the control device 14 sends a control signal to the valve operating means to close the open / close valve 5 and supply the liquid. Stop. The number of filling pulses is determined by conducting a test in advance.

  In addition, using this kind of flowmeter in a liquid filling device is known per se as exemplified in Patent Documents 3 to 7 below.

JP 2003-95391 A JP-A-7-223601 Japanese Patent Laid-Open No. 11-193095 JP 11-171104 A JP 11-105989 A Japanese Patent Laid-Open No. 10-16903

  The flow rate in the liquid pipe line 2 measured by the flow meter 4 is such that the liquid pressure is constant when the liquid flows through the pipe line at a flow rate higher than a certain level, that is, when the on-off valve 5 is fully open. Even without it, it can be measured accurately. However, when the opening / closing valve 5 is opened or closed, the flow rate (the amount of jump) of the liquid flowing in the liquid conduit 2 is difficult to measure accurately because the flow velocity is small and changes rapidly, and the flow rate is Fluctuates greatly depending on hydraulic pressure. Therefore, in the flow meter type liquid filling apparatus, in order to keep the amount of liquid filled in the container including the diving amount constant, it is necessary to keep the liquid pressure in the liquid pipe line constant.

In the filling device shown in FIG. 5, particularly when the liquid is replenished from the liquid replenishment tank 6 to the liquid storage tank 1, the replenishment is performed relatively rapidly, so that the pressure in the liquid storage tank 1 fluctuates (rises). Although it is easy, the air pressure adjusting means 10 can keep the pressure almost constant, and the liquid pressure in the liquid pipe 2 is also kept almost constant. As a result, the amount of liquid filled in the container can be kept substantially constant at the target value.
However, when aseptic filling is performed using this type of filling device, the pressure fluctuation in the liquid storage tank 1 cannot be sufficiently suppressed, and the amount of liquid filled in the container varies greatly from the target value. is there. In the case of aseptic filling, it is necessary to provide a sterilization filter in the air flow path connecting the liquid storage tank 1 and the air pressure adjusting means 10, and this sterilization filter serves as a resistance for air flow, and the air pressure adjusting means This is because the pressure fluctuation cannot be adjusted quickly even when the pressure sensor 10 is operated (air is not discharged quickly).

  When the pressure in the liquid storage tank 1 fluctuates, the liquid pressure in the liquid pipe also fluctuates, and the amount of jumping changes, resulting in variations in the filling amount of the container. Also, the shorter the time from the start to the end of filling, the greater the influence of the jumping amount, so the variation in filling amount increases as the productivity (pieces / minute) of the filling device increases.

  The present invention has been made in view of such problems of the prior art, and suppresses variations in the filling amount of the container even if the pressure in the liquid storage tank fluctuates or increases the productivity. An object of the present invention is to obtain a flow meter type liquid filling device capable of

The present invention includes a liquid storage tank pressurized to an atmospheric pressure or more, a filling nozzle that communicates with the liquid storage tank through a liquid conduit, and the discharge of liquid from the filling nozzle installed in the liquid conduit or the filling nozzle and A valve for stopping the valve, a valve operating means for opening and closing the valve, a pressure sensor for measuring a pressure in the liquid storage tank or the liquid pipe, and a flow through the liquid pipe when the valve is open to the filling nozzle Measures the flow rate of the liquid to be sent and outputs a pulse signal at a constant flow rate, and operates the valve operating means to open the valve to start filling, and the number of input pulse signals is a predetermined amount When the number of pulses is reached, in the flow meter type liquid filling apparatus provided with a control device that operates the valve operating means to close the valve and stop the filling, the control device is connected to the pressure sensor. Based on the pressure value measured immediately before starting filling, the number of filling pulses corresponding to the pressure value is calculated for each filling from the relationship between the preset pressure value and the number of filling pulses. .
More specifically, this calculation procedure compares the pressure value with a preset pressure reference value to calculate a pressure fluctuation value, and is calculated from the relationship between the preset pressure fluctuation value and the number of charging pulses. Further, the number of filling pulses corresponding to the pressure fluctuation value is calculated. More specifically, the correction pulse number corresponding to the calculated pressure fluctuation value is obtained from the relationship between the preset pressure fluctuation value and the correction pulse number, and is set in advance corresponding to the pressure reference value. The filling pulse number is calculated from the reference pulse number and the correction pulse number.

The installation position of the pressure sensor may be in the liquid storage tank (measure the air pressure or liquid pressure in the tank) or in the liquid pipe (measure the liquid pressure in the pipe). If it is in the liquid pipeline, a location closer to the flow meter and the filling nozzle is desirable.
The flow meter type liquid filling device further includes a liquid replenishing unit connected to the liquid storage tank, and an air pressure adjusting unit for adjusting an air pressure in the liquid storage tank, and the control device detects a detection signal of the pressure sensor. Based on the above, the air pressure adjusting means is operated to keep the pressure value constant. In addition, the flow meter type liquid filling device includes a sterilization filter between the liquid storage tank and the air pressure adjusting means, if necessary.
In the present invention, the term “liquid” is used to mean a liquid material including a solid material.

  According to the present invention, based on the knowledge that when the pressure in the liquid storage tank or the liquid pipeline fluctuates from the reference value, the appropriate number of filling pulses for filling a certain amount of liquid changes. The relationship between the pressure value and the number of filling pulses is determined experimentally, the pressure value is measured for each filling, the number of filling pulses corresponding to the pressure value is calculated from the relationship, and the pulse from the start of filling When the number reaches this number of filling pulses, the valve is automatically closed. Therefore, even if the pressure in the liquid storage tank or the liquid pipe line fluctuates, the filling can be performed with the optimum number of filling pulses corresponding to the pressure value for each filling, and the fluctuation of the filling amount accompanying the pressure fluctuation Can be kept to a minimum.

Hereinafter, with reference to FIGS. 1-4, the flowmeter type liquid filling apparatus which concerns on this invention is demonstrated.
The filling device shown in FIG. 1 is for aseptic filling. Compared with the filling device shown in FIG. 5 (basically, the same parts are given the same numbers), the air pressure adjusting means 10 is usually used. A sterilization filter 23 in the air flow path connecting the liquid storage tank 1 and the air pressure adjusting means 10, and a sterilization filter 24 in the air flow path connecting the liquid replenishing tank 6 and the air pressure adjusting means 11. It differs in that it is installed.
In addition, the control device 14 measures the air pressure in the liquid storage tank 1 by the pressure sensor 8 immediately before the start of filling, and calculates an appropriate number of filling pulses corresponding to the air pressure for each filling. When the number of pulse signals output from the total 4 reaches the number of filling pulses, the valve actuating means is actuated to close the valve 5 and the filling is stopped. In the conventional control device shown in FIG. 5, the number of filling pulses set at the beginning of the filling operation is not changed during the filling operation.

An example of the procedure for calculating the number of filling pulses (F) by the control device 14 will be specifically described with reference to the flowchart of FIG.
[S1] When the pressure interlock switch of the control device 14 is turned ON, calculation of the number of filling pulses by the control device 14 is started.
[S2] The controller 14 measures the air pressure in the liquid storage tank 1, that is, the filling start pressure (A) by the pressure sensor 8 immediately before the valve 5 is opened by operating the valve operating means.
[S3] The measured filling start pressure (A) is compared with a preset pressure reference value (B), and a pressure fluctuation value (C) is calculated from the following equation. The pressure reference value (B) is determined experimentally together with the following reference pulse number (E), and generally varies depending on the properties of the liquid, the target filling amount, the time available from the start of filling to the end of filling, and the like. .
C = A−B (1)

[S4] The correction pulse number (D) corresponding to the pressure fluctuation value (C) is calculated from the relationship between the correction pulse number (D) and the pressure fluctuation value (C) defined by the following equation. The function f is determined experimentally. When C = 0, D becomes 0, when C> 0, D becomes a positive number, and when C <0, D becomes a negative number.
D = f (C) (2)
[S5] The filling pulse number (F) is calculated from the correction pulse number (D) and the reference pulse number (E) by the following equation. However, both the positive and negative values of D are rounded down or rounded up. The reference pulse number (E) is a pulse number for obtaining a target filling amount when the air pressure in the liquid storage tank 1 is equal to the pressure reference value (B) (C = 0), as described above. , Determined experimentally.
F = ED (3)

  As shown in the above formulas (1) to (3), in the control device 14, the relationship between the air pressure in the liquid storage tank 1 (or the deviation from the reference value) and the number of filling pulses (F) is set in advance. From this relationship, the number of filling pulses (F) corresponding to the filling start pressure (A) is calculated. Next, when the number of pulse signals output from the flow meter 4 reaches the number of filling pulses, the control device 14 operates the valve operating means to close the valve 5 and stops filling.

The liquid filling device of the type shown in FIG. 1 is arranged in the liquid filling process of the intermittent rotary table type bag filling and packaging machine, the production amount is set to 30 bags / minute, the target filling amount is set to 200 ml (g), and the liquid is poured into the bag. Filled. The liquid used is room temperature water, the filling nozzle 3 is a net nozzle having an inner diameter of 20 mm, the flow meter 4 is an electromagnetic flow meter, the capacity of the liquid storage tank 1 is 60 l, and the capacity of the liquid replenishing tank 6 is 80 l. The pressure reference value (B) in the liquid storage tank 1 is set to 89 kPa, the reference pulse number (E) is set to 75 pulses, and the pressure in the liquid storage tank 1 is measured for each filling as described above. The number of filling pulses was calculated, and the valve 5 was controlled based on the number of filling pulses.
In this example, an experiment was conducted in advance on the relationship between the air pressure in the liquid storage tank 1 and the number of filling pulses, and the equation (2) was set as follows. The coefficient k is 1.7, and the unit of C is kPa.
D = k × C (4)

FIG. 3 shows the pressure (filling start pressure) and filling amount in the liquid storage tank 1 for each filling.
As shown in FIG. 3, the pressure in the liquid storage tank 1 varies considerably every time the liquid is replenished from the liquid replenishing tank 6. This is because the sterilization filter 23 is connected between the liquid storage tank 1 and the air pressure adjusting means 10, and this becomes a resistance, and air pressure adjustment at the time of liquid replenishment cannot be performed quickly. However, the fluctuation of the filling amount was small, and for the 50 bags tested, the average value of the liquid filling amount was 200.5 g, and the difference between the maximum filling amount and the minimum filling amount was 4.3 g.
On the other hand, FIG. 4 shows the results when the number of filling pulses is not corrected (all the 50 bags have the same filling pulse number), and the other conditions are the same (comparative example). The pressure in the liquid storage tank 1 fluctuates similarly, and the filling amount also fluctuates considerably to correspond to this fluctuation. The average value of the liquid filling amount is 201.4 g for the 50 bags tested, and the maximum filling amount And the difference between the minimum filling amounts was 9.8 g, and the variation was large.

  The pressure regulating valve used in the liquid filling apparatus in FIG. 1 is inferior in accuracy to the air pressure adjusting means used in the apparatus in FIG. 5, but the liquid filling apparatus in FIG. In the liquid filling apparatus shown in FIG. 1, the pressure value is measured for each filling and the optimum number of filling pulses corresponding to the pressure value is calculated. Therefore, since the filling amount control with high accuracy is possible even if there is a pressure fluctuation, the pressure regulating valve may be used.

The above description relates to a liquid filling device including a sterilization filter between the liquid storage tank and the air pressure adjusting means. However, the present invention is a liquid in which the pressure in the liquid storage tank may fluctuate. As long as it is a filling device, it can also be applied to devices that are not equipped with a sterilization filter.
In the liquid filling apparatus shown in FIG. 1, since the liquid is replenished from the pressurized liquid replenishment tank to the liquid storage tank, the liquid is replenished relatively quickly, and the air pressure in the liquid storage tank is replenished. Every time it fluctuated greatly. Instead of this method, as described in Patent Document 1, it can be replenished using a pump installed in the liquid pipe. Since the liquid can be gradually replenished with a pump, the pressure fluctuation in the liquid replenishment tank becomes relatively small.
In addition, the pressure sensor measures the air pressure in the liquid storage tank, but instead, it can also measure the liquid pressure in the liquid storage tank or in the liquid conduit. If it is in the liquid line, the accuracy is improved if it is measured in the vicinity of the flow meter or the filling nozzle. Further, as the flow meter, not only an electromagnetic flow meter but also a mass flow meter that outputs a pulse signal at every constant flow rate can be used.

It is a circuit diagram of a flow meter type liquid filling device concerning the present invention. It is a flowchart which shows the control procedure in the apparatus of this invention. It is a figure which shows the pressure and the filling amount in the liquid storage tank of an Example for every filling. It is a figure which shows the pressure and the filling amount in the liquid storage tank of a comparative example for every filling. It is a circuit diagram of the conventional flowmeter type liquid filling apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid storage tank 2 Liquid pipe line 3 Filling nozzle 4 Flowmeter 5 On-off valve 6 Liquid replenishment tank 7 Liquid level sensor 8 Pressure sensor 9 Pressurized air source (compressor)
10, 11 Air pressure adjusting means 23, 24 Bacteria-removing filter

Claims (5)

A liquid storage tank pressurized to an atmospheric pressure or higher, a filling nozzle communicating with the liquid storage tank by a liquid conduit, and discharging and stopping the liquid from the filling nozzle installed in the liquid conduit or the filling nozzle A valve, valve actuating means for opening and closing the valve, a pressure sensor for measuring the pressure in the liquid storage tank or in the liquid pipe, and the flow of liquid sent to the filling nozzle through the liquid pipe when the valve is open A flow meter that measures the flow rate and outputs a pulse signal at a constant flow rate, and operates the valve operating means to open the valve to start filling, and the number of input pulse signals reaches the predetermined number of filling pulses In the flowmeter type liquid filling apparatus that includes a control device that operates the valve operating means to close the valve and stops the filling, and repeatedly performs the same filling operation, the control device includes: Based on the pressure value measured immediately before the start of filling by the pressure sensor, the number of filling pulses corresponding to the pressure value is calculated for each filling from the relationship between the preset pressure value and the number of filling pulses. A flow meter type liquid filling device. The control device calculates the pressure fluctuation value by comparing the pressure value with a preset pressure reference value, and calculates the pressure fluctuation value from the relationship between the preset pressure fluctuation value and the number of filling pulses. 2. The flowmeter type liquid filling apparatus according to claim 1, wherein a corresponding number of filling pulses is calculated. A correction pulse number corresponding to the calculated pressure fluctuation value is obtained from the relationship between the preset pressure fluctuation value and the correction pulse number, and the reference pulse number and the correction pulse preset corresponding to the pressure reference value are obtained. 3. The flow meter type liquid filling apparatus according to claim 2, wherein the number of filling pulses is calculated from a number. Furthermore, a liquid replenishing means connected to the liquid storage tank and an air pressure adjusting means for adjusting the air pressure in the liquid storage tank are provided, and the control device operates the air pressure adjusting means based on a detection signal of the pressure sensor. The flow meter type liquid filling device according to claim 1, wherein the pressure value is kept constant. The flowmeter type liquid filling apparatus according to claim 4, further comprising a sterilization filter between the liquid storage tank and the air pressure adjusting means.

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