FI110504B - Method and apparatus for dispensing fluid - Google Patents

Description

1 110504

Method and apparatus for dispensing fluid

The invention relates to a method for dispensing a fluid of the type set forth in claim 1. The invention also relates to a device for dispensing a fluid of the type set forth in the preamble of claim 12.

In many processes, a predetermined amount of fluid to be applied to the target should be periodically metered. Such processes are, in particular, those of the type in which objects to which the dosing takes place pass successively past the dosing point.

Particularly when dispensing small volumes of liquid, great precision is required. With pumps that can be adjusted to deliver a certain amount of fluid during the 15 pumping steps, this accuracy is often not achieved. One particular application where accurately measured amounts of liquid are required is a method of treating successive objects in a continuous stream in a process in which the articles are treated with equal amounts of liquid. An example of such processes is the sterilization processes of the food industry, such as the inside sterilization of later refillable liquid packages. In sterilization, it is important to: · · ·: get the right amount of active ingredient to influence the packaging to ensure a certain shelf life for the packaging: · · f.

25 Food packaging processing lines, one part of which is a sterilization device before packaging filling and sealing devices are shown, inter alia, in Figs. European Patent 479010. A mechanical solution for transferring a certain volume of liquid into a dispensing line is disclosed in European Application Publication 353486. In relation to one another, the moving parts cause sealing problems and the volume of the liquid cannot be adjusted.

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EP 0 290 724 discloses a dispenser for dispensing, for example, a liquid used for sterilization. Excess pumped · · 35 spilled liquid flows into the intermediate reservoir through the outlet between the outer surface of the intermediate reservoir and the dispenser sheath for reuse. The intermediate reservoir has a metering passageway set up at a certain depth 2 110504 through the upper reservoir, i.e. the mouth of the intermediate reservoir, which absorbs the volume of liquid between the mouth of the intermediate reservoir and the mouth of the metering passage to deliver the liquid dose to its application. Liquid dosing is monitored by measuring the resistance between the first measuring electrode formed by the intermediate container and the second measuring electrode formed by the an-5 lifting channel.

Finnish patent 105796, for its part, discloses a method and apparatus for precisely and repeatedly dispensing small amounts of liquid, in particular at the speed required by the process and with certainty. The presence of fluid between the overflow point and the mouth of the metering channel is monitored by two sensors at different heights adjacent to the intermediate cavity. Sensors can be used to ensure that dosing is working properly. Hereby, one can observe e.g. cases in which 15 parts of the intermediate tank remain unfilled.

The object of the invention is to improve the reliability of the method and device described above and to provide a device and method in which the filling of the intermediate container can be unambiguously and reliably determined. To accomplish this object 20, the method is essentially characterized in what is set forth in the characterizing part of claim 1 below. When: ··: The liquid flow is monitored after the overflow point, it can be stated: ··: with high certainty the filling of the intermediate tank. In accordance with the invention. the apparatus, in turn, is characterized by what is set forth in the characterizing part of claim 12 of the appended claim 25.

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For other preferred embodiments of the invention, reference is made to the appended dependent claims and to the description which follows.

The invention will now be further described with reference to the accompanying drawings, in which:

Fig. 1 is a simplified view of the device of the invention prior to dispensing the liquid, M 35 of Fig. 2 shows the same after dosing, 3 110504 of Fig. 3 is a side view of the structure of the device, and Fig. 4 is a diagram of

Figure 1 shows a simplified view of the device illustrating the principle of operation. The body of the device has a vertical channel forming an intermediate reservoir 1, e.g. of circular cross-section, the upper end of which slopes an overflow point 1a through a junction 10 between drains along an inclined downwardly sloping surface of the outlet duct. In Figure 1, the free liquid surface as determined by the overflow point 1a is denoted by the reference S.

The dispensing channel 2, which may be a suitable hose or the like, is introduced from below into the intermediate container 1. The dosing channel 2 terminates at a certain height before the free liquid surface S defined by the overflow position 1a. The mouth opening 2a at the end of the channel 2 is located at a certain height h from the liquid surface S below it. The amount of liquid M to be dispensed is then determined by the volume of liquid remaining between the mouth 2a of the dispensing channel 2 and the liquid surface S.

: .. j Figure 1 shows the situation where the intermediate tank 1 is filled from below. ···. pumping so that the liquid has risen around and within the dosing passage 2 and the liquid surface has settled to the height specified by the overflow point 1a, and the liquid has flowed into the outlet passage 5 over the overflow point 1a. Thereafter, in one sufficiently long suction step, the volume of liquid in the intermediate container 1, i.e. the amount of liquid M, is sucked through the opening 2a of the dosing channel 2 and is led along the dosing channel 30 to the dosing destination. Thereafter, the liquid surface in the refill container 1 is located by determining the location of the dosing port orifice 2a. at a lower height, as shown in Figure 2.

Further, it is advantageous to continuously adjust the amount of liquid to be dispensed.

This is accomplished by continuously adjusting the distance of the orifice 2a of the dispensing channel 2 from the overflow point 1a, whereby the volume of the liquid determined by the distance S of the liquid surface S and the orifice 2a, i.e. height h, changes accordingly. To accomplish this, the dosing channel 2 may be vertically displaceable by a suitable, accurately positioned actuator.

When the intermediate container is full and excess fluid flows over the overflow point 1a into the outlet duct 5, this is detected by a sensor 3 disposed to detect the presence of liquid in the outlet duct 5. The sensor 3 may operate, for example, on a capacitive basis. When the sensor 3 10 detects that the intermediate container 1 is full (fluid in the outlet duct 5), the fluid supply control device may be instructed to stop the supply to the intermediate container 1. The sensor may also be used for mere confirmation, i. that the intermediate container 1 is filled when carrying out the normal operating sequence. The second sensor 3 is arranged to monitor at least the area which is filled and discharged during dispensing, i.e. the area between the overflow point 1a and the port 2a of the dispensing channel in the height of the intermediate container. This sensor may be, for example, a photoelectric cell positioned at a convenient location in the metering device body sufficiently close to the intermediate container. The data of this sensor can also be used to control and ensure the functions of the dispenser 20. Advantageously, the sensor 3 is also movable in the height direction of the intermediate container 1, according to the respective height ·: ·· .: position of the dispensing channel opening 2a. The transducer 1 monitoring sensor 3 is near the lower end of the fluid volume to be dispensed, ie slightly. 2, which remains in the intermediate container 25 in the position of Figure 2 after dosing has taken place. Thus, by means of the sensor 3 of the outlet duct 5, it is possible to ensure that the intermediate container 1 is full before dosing and by the sensor 3 of the intermediate container 1, that the volume to be dispensed is safely discharged from the intermediate container 1 after dosing. The information provided by both sensors 3 must be the same when the intermediate tank is full (liquid '...: 30 in outlet duct 5 and intermediate tank 1), and this principle can be used to detect ...: malfunctions.

Fig. 3 is a side view of the device D comprising an intermediate container and an outlet duct. The intermediate container 1 is disposed vertically in a tubular • '.' • j 35 piece housing with a top and bottom end having mounting pieces for different connections. The mounting piece at the upper end of the body is provided with an oblique drill which joins a vertical drilling for positioning the intermediate container 110504 to accommodate a pipe acting as an outlet duct 5. In this case, a pipe connection piece is placed in the bore. At the junction of the boreholes, the above-described overflow point 1a is created. A supply channel 4 is connected to the mounting member 5 at the lower end via a solenoid valve V, which communicates with the tubular intermediate container 1 which is lowered into the bore inside the lower mounting member. Inside the tubular intermediate container 1, concentric therewith extends from top to bottom the dosing channel 2, which extends downwardly into the lower mounting member 10 apart from the other bores, and is connected at its lower end to an outlet bore with an ejector acting as dosing actuator R. At the lower end of the ejector is a dosing nozzle N. The feed duct 4 comes from the pump via a solenoid valve V, and the valve is arranged to direct the flow of material into the free circulation return duct 7 when the supply to the intermediate tank 1 is to be stopped.

The sensor 3 is fastened to a bracket protruding from the body near the wall of the outlet duct 5 so that it can detect changes in the amount of liquid in the outlet duct 5, and especially since the liquid supplied through the supply duct 20 begins to flow over the overflow point 1a. Sensor 3 can be used to control the operation of the ·: ··: solenoid valve. Also shown in the figure is another sensor 3, which is disposed in connection with the intermediate container 1 and is inserted through e.g. the wall of the housing-like body close to the intermediate container 1.

25: ./ Figure 4 shows schematically the location of the device D in a continuous * '··· * manufacturing or processing process. In the treatment process, there are successive objects E, in this case separate objects, passing by the dosing point (dosing nozzle N), which are subjected to • · · 30 treatment with the same amount of liquid. Figure 4 also shows a filling pump P, which is connected via valve V to a device D comprising an outlet duct 5 and an outlet duct 5 via an inlet duct 4.

"* The filling pump P is arranged to supply a larger metering unit

the substance reservoir 6 dosing agents in a continuous fluid flow. When:. * ·· 35 intermediate tank 1 is filled to overflow position 1a, turn valve V

flow for free circulation to the return channel connected to the tank 6, i.e. the by-pass channel 7, while the pump P is running continuously. Excess 6 110504 fluid is always discharged through outlet duct 5 to the same container 6, and intermediate tank 1 is sure to be filled up to overflow point 1a when valve V has switched flow from by-pass channel 7 to intermediate tank. The dispensing actuator R, in turn, is arranged to suck the liquid volume 5 from the intermediate container 1 through the dispensing channel 2 and to supply the liquid to be dispensed to the dispensing object. The free circulation in the container 6 prevents the bubbling liquid from bubbling. Because the pump is continuously pumped through several successive dosing operations, the properties of the fluid to be pumped are minimized by the pumping.

The filling pump P may be any pump capable of pumping liquid to the overflow position 1a of the intermediate container at a flow rate determined by the dosing rate. A suitable example is an electric centrifugal pump 15. The dosing actuator R can be any device providing suction to channel 2, for example the ejector structure described above, whereby the gaseous medium passed through the ejector provides the required suction to suck up the volume of liquid between the overflow point 1a and the mouth 2a. Also, a pump with 20 moving parts, such as a diaphragm pump, is possible.

...: Figure 4 shows the food packaging to be sterilized before filling. a pre-determined amount of sterilizing agent. The sterilizing agent may be a mixture of hydrogen peroxide and water, which is sprayed together with the filtered compressed air into the packaging. ejector structure and carries 30 sterilizers to a destination The volume of sterilant fluid dispensed by the device D is small, typically less than 1 ml.

The device D comprising the intermediate container and the outlet duct shown in Fig. 3 may be ... 'I' arranged at least partially transparent so that the intermediate container 1 can be visually observed externally at least at the height of the liquid volume 35 to be dispensed. The tubular vertical intermediate container 1 may be transparent 7 110504 glass or plastic. Likewise, at least one of the suture walls of an upright enclosure body may be transparent glass or plastic.

Although the above describes mainly dosing of a sterilizing agent, the invention can be used in principle for dispensing all liquids, especially in processes where the same amount of fluid is repeatedly dispensed to successive targets in the process.

The liquid may be a substance for treating successive objects, but the liquid may also be intended to fill successive objects with a precisely defined volume that remains permanently in the volume of liquid within the subject.

Likewise, the invention can be used to dispense liquids in predetermined amounts into sequential targets, e.g., sequential object receiving spaces, for mixing a liquid with substances already present or to be added thereafter in the manufacturing process. The invention is particularly well suited for small volumes of less than 10 ml and especially for volumes less than 1 ml. The device can be calibrated such that a certain elevation position of the orifice 2a always corresponds to a certain amount of fluid.

For automating the dosing rhythm in the process of successive objects ..V: known automation solutions can be used to control the dosing actuator R to which the aforementioned sensor (s) can be connected. The filling pump P runs continuously and the dosing actuator R can be synchronized to operate in cycles at the correct time with respect to the movement of the process objects. Likewise, valve V may be synchronized to operate by switching the · ··· * fluid supply connection to the intermediate tank 1 in some manner synchronized with the operation of the dosing actuator R, i.e., the valve V will begin to direct flow again to the intermediate tank 1 after it has been emptied.

30 Well-known automation solutions can be used here.

The device is not limited to the structure limited above, but may be modified within the inventive idea of the claims. The dispensing channel 2 need not necessarily be located in the intermediate container 35 but may be outside and the opening 2a may open into the wall of the intermediate container 1 at a suitable height below the overflow point 1a, but such a structure is difficult to adjust.

8 110504

Similarly, according to the arrangement disclosed in FI-105796, the dosing channel 2 can be introduced from above via the free liquid surface S, whereby it also ends at a certain height below the liquid surface S defined by the overflow position 1a.

5

Several independent metering units having their own valves V, intermediate tanks 1 and metering actuators can be connected to the same tank 6 and pump P and each can be independently controlled according to the required metering rate.

10

Likewise, liquid dispensing refers to a substance in the initial state which is a liquid which can be removed from the intermediate container in certain volumes of liquid but which, in its entirety or its components, can change its state between the intermediate container and the actual dispensing object.

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Claims (21)

A method of dosing liquid in which an intermediate container (1) is filled and a predetermined amount of liquid (M) is conducted from the intermediate container to a particular target, whereby when the intermediate container is filled, an additional amount of liquid is passed through an upper end of the intermediate container. the existing tray drain (1a) and the amount of liquid (M) are removed from the intermediate container through a predetermined distance from the free liquid surface (S) entrance opening (2a) of a dosing channel (2), and the presence of the liquid amount (M) between 1a) and the entrance opening (2a) of the dosing channel (2) is monitored by a sensor (3), characterized in that with the sensor the flow of the liquid which has flowed over the overflow drain (1a) is monitored and thus filling of the intermediate container (1) is detected. ). 15 Method according to claim 1, characterized in that the presence of the liquid in the intermediate container (1) is monitored directly with also a second sensor (3), which is placed in communication with the intermediate container (1), so that with it the one in the intermediate container (1) existing amount of fluid can be detected. Method according to Claim 1 or 2, characterized in that the * * sensor, which monitors the flow of the liquid which has cooled over the drain (1a), is used to automatically control the feeding of [the liquid into the intermediate container (1) in its filling phase. Method according to claim 3, characterized in that the flow of the liquid into the intermediate container (1) is controlled by changing the flow to another medium instead of the intermediate container (1). 30 Method according to claim 4, characterized in that the flow is conducted instead of the intermediate container to a free circulation back into. * ·· the container (6), from which the liquid to be dosed is measured in between the container (1). O * 35 6. A method according to claim 5, characterized in that the flow: of the liquid which has cooled over the overflow drain (1a) is led back into the container (6), from which the liquid to be dosed is measured into the intermediate container (1). Process according to any of the preceding claims, characterized in that the amount of liquid is removed by sucking it into the dosing channel (2) which is brought down from a predetermined distance (h) from the free determined by the drain (1a). the liquid surface (S). 10 Method according to any of the preceding claims, characterized in that the intermediate container (1) is filled by pumping into the more liquid from below in such a way that the upper surface of the liquid rises to the level of the width-drain (1a) and the sensor (3). ) detects the fluid flow coming across the width drain (1a). 15 Method according to any of the preceding claims, characterized in that it is used for dosing liquid for a continuous manufacturing or treatment process for successive mills and in this cycle cycles are repeated with the following successive steps: filling of the intermediate container. and to the drain (1a), and - removal of the amount of liquid (M) from the intermediate container through the dosing channel (2). 25 Process according to any of the preceding claims, characterized in that the amounts of liquid (M) to be dosed are below 10 ml, especially below 1 ml. 30 Method according to claim 9 or 10, characterized in that it. . is used for dosing a sterilizing agent successively in one ':. 'Process is ongoing, such as food packaging (E). A device (D) for dosing a liquid, comprising: ··. An intermediate container (1), an inlet channel (4) for filling the intermediate container (1), and a metering channel (2) located between the intermediate container and a predetermined stock for dispensing a predetermined amount of liquid (M) to the meter, wherein the upper portion of the intermediate container is provided with a drain (1a) which determines the position of liquid level in the intermediate container (1), and the entrance opening (2a) of the dosing channel (2) is positioned in the intermediate container at a predetermined distance from the board drain (1a) below. the device further comprises a transducer (3), characterized in that the transducer (3) is positioned in the flow direction of the liquid after the overflow drain (1a) to detect the filling of the intermediate container (1) with the amount of liquid (M). Device according to claim 12, characterized in that it further comprises a second sensor (3), which is placed in communication with the intermediate container (1) for detecting the amount of liquid (M) in the area between the drain drain (1a) and the entrance opening (2a). . Device according to claim 12 or 13, characterized in that the transducer (3) located after the drain drain (1a) operates according to the capacitive principle. Device according to claim 12, 13 or 14, characterized in that the transducer (3) located after the drain drain (1a) is arranged to control a valve (V) located in the feed duct (4) arranged to change the flow from the channel, which opens into the intermediate container (1), into a return channel (7). Device according to any of the preceding claims 12-15, characterized in that the dosing channel (2) is arranged from below to the intermediate container (1). Device according to any one of the preceding claims 12-16, characterized in that the distance between the entrance opening (2a) of the dosing channel (2) and that in connection with the intermediate container (1): the positioned sensor (3) from the overflow drain (1 a) is continuously adjustable. Apparatus according to any of the preceding claims 12-17, characterized in that the inlet duct (4) for filling the intermediate container is connected to the intermediate container (1) below the entrance opening (2a). ie 110504 Device according to any of the preceding claims 12-18, characterized in that the sump drain (1a) is formed at the junction of the intermediate container (1) and an inclined drain channel (5). 5 Apparatus according to any of the preceding claims 12-19, characterized in that it is placed in conjunction with a continuous manufacturing or processing process and is arranged to dose one substance in succession in the process, wherein the other end of the channel (2) is on the runway. 21. Device according to claim 20, characterized in that it is a device for dosing a sterilizing agent. »