GB2251607A

GB2251607A - Method and machine for the filling of containers

Info

Publication number: GB2251607A
Application number: GB9127061A
Authority: GB
Inventors: Heinrich Landwehr
Original assignee: Haver and Boecker OHG
Current assignee: Haver and Boecker OHG
Priority date: 1991-01-11
Filing date: 1991-12-20
Publication date: 1992-07-15
Anticipated expiration: 2011-12-20
Also published as: DE4100658A1; ITGE910151A1; GB9127061D0; DE4100658C2; GB2251607B; ITGE910151A0; CH683906A5; IT1262885B

Abstract

A method of filling containers such as valve bags provides for enhancement of the flowability of the filling material by way of compressed air which is added if and only if the material flow is irregular. During the filling process, the weight increase per unit time of each container is detected. If the detected value falls below a given value respective to the particular material, it can be inferred therefrom that the material flow is subject to fluctuations. Throttle valves provided in the compressed air feed ducts are then opened. The method is particularly suitable for valve bag filling machines equipped with a filling impeller and a filling pipe.

Description

2 2 5) 16 -) 7 - 1 Method and Machine for the filling of containers The

present invention relates to a method of filling containers with a flowable material and to a filling machine for carrying out the method.

In practice, various products with different physical properties are filled by means of filling machines. In the case of filling materials with poor flowability it may be necessary to add compressed air to the material to improve flowability. The compressed air is blown into a filling impeller housing, so that the material leaves this housing. The air can also be blown into a filling pipe, or into both the pipe and the impeller housing. However, the addition of compressed air is not required just in the case of poorly-flowing materials, but also in the case of materials which lose their usual good flowability when a relatively short stoppage of the filling machine occurs. Such stoppage times can be due to, for example, breaks in the machine work. It is then necessary, after restarting of the filling machine, to add compressed air. Naturally, the switching off is then omitted after the first filling processes. It is necessary for the filling of the containers that the filling material flow is uniform, as fluctuations cause the actual weights of the filled containers to be different in undesired manner. The containers to be filled may be flexible, for example valve bags. The quantity of supplied compressed air, however, should be kept as small as possible as the air causes the container to swell. Disturbances in the packaging operation then result. Moreover, the outer surfaces of the containers may be soiled when they are pushed-off the filling 2 - pipe. Accordingly, the air supplied shall be only as much as is strictly necessary, although blocking of the filling pipe must be avoided, as this would require the machine to be shut down and the filling pipe to be cleaned with a substantial cost in time. The compressed air is supplied by way of ducts and regulation of the air quantity is effected manually by means of throttle valves.

There is thus a need for a filling method by which the flowability of filling material can be increased by the addition of air only if the filling process is subjected to a fluctuating filling flow and there is a risk of blocking of feed duct means. Preferably, also, the outer surfaces of flexible containers, as well as the filling machine and the environment thereof, should be less liable to soiling. Moreover, such a method should preferably be capable of being performed by a constructionally simple filling machine, and the possibility should also exist to subsequently equip machines already in operation so that they can perform the method.

According to a first aspect of the present invention there is provided a method of filling containers with a flowable material by way of an impeller and duct means, comprising the steps of ascertaining the speed of flow of the material in the duct means by detecting the increase in weight of each container per unit time during filling thereof, comparing an actual value indicative of the detected increase with a predetermined value specific to the kind of material, and supplying compressed air at a settable rate by way of valve means to at least one of the impeller and the duct means to increase the flow speed of the material if and only if the actual - 3 value is less than the predetermined value..

According to a second aspect of the invention there is provided afilling machine for carrying out the method of the first aspect of the invention, the filling machine comprising duct means for conducting flowable material to containers to be filled, an impeller for causing movement of the material in the duct means, means for ascertaining the speed of flow of the material in the duct means by detecting the increase in weight of each container per unit time during filling thereof, and means for comparing an actual value indicative of the detected increase with a predetermined value specific to the kind of material and for causing compressed air to be supplied by way of valve means to at least one of the impeller and the duct means to increase the flow speed of the material if and only if the actual value is less than the predetermined value.

In a preferred example of the method and embodiment of the filling machine of the invention, given values for different materials to be filled into containers such asvalve bags by a filling machine are known to the manufacturer and to the user. These values can be stored i n a store of the filling machine, so that, for example, the value respective to a particular material can be activated before the start of the filling process by switching on a switch. This value is calculated on the basis of unit time in which the container weight increase is detected. If during the filling this value is exceeded, it can be inferred therefrom that the material can be supplied without addition of air. If this value is fallen below, which is usually due to an irregular filling flow, the flowability of the material must be increased by blowing in compressed air. Through continuing detection of the weight increase, compressed air isblown in only if and when it is actually required. Thus, it may be the case that for the first filling processes after starting up of the machine, air must be added, but after a few filling process the material is sufficiently flowable. The method exemplifying the invention can be particularly simply performed if the filling machine is equipped with electronically operating weighing means, which for other reasons already serves to detect the weight increase per unit time, so that in advantageous manner the weight increase per unit time for each filling process is conveniently capable of detection.

In the preferred embodiment of the filling machine, therefore, the machine has an electronically operating balance and the result of a comparison between the given value and the detected weight of the container increase per unit time is used as control signal for the actuation of a valve or valves. The or each val ve can be an electromagnetic valve with an on-off function. If it is established that the weight increase per unit time falls below the given value, the or each valve is opened, and is closed on the exceeding of the given value. The or each valve controls one or more compressed air ducts, which feed compressed air to the interior space of a filling impeller or turbine of the machine and/or into a filling pipe of the machine. The or each can be a throttle valve and the supplied compressed air can be settable according to quantity.

Claims

1 - A method of filling containers with a flowable material by way of an impeller and duct means, comprising the steps of ascertaining the speed of flow of the material in the duct means by detecting the increase in weight of each container per unit time during filling thereof, comparing an actual value indicative of the detected increase with a predetermined value specific to the kind of material and supplying compressed air at a settable rate by way of valve means to at least one of the impeller and the duct means to increase the flow speed of the material if and only if the actual value is less than the predetermined value.

2. A method as claimed in claim 1, wherein the step of ascertaining the flow speed comprises detecting the increase in container weight by means of weighing equipment during filling of each container

3. A method as claimed in claim 1 and substantially as hereinbefore described.

4. A filling machine for carrying out the method claimed in claim 1, comprising duct means for conducting flowable material to containers to be filled, an impeller for causing movement of the material in the duct means, means for ascertaining the speed of flow of the material in the duct means by detecting the increase in weight of each container per unit time during filling thereof, and means for comparing an actual value indicative of the detected increase with a predetermined value specific to the kind of material and for causing compressed air to be supplied by way of valve means to at least one of the impeller and the duct means to increase the flow speed of the material if and only if the actual value is less than the predetermined value.

5. A filling machine as claimed in claim 4, wherein the means for ascertaining comprises electronically controllable weighing means for weighing each container during filling thereof.

6. A filling machine as claimed in claim 4 or claim 5, wherein the means for comparing the values and causing compressed air to be supplied is arranged to issue a signal for opening of the valve means in response to the actual value falling below the predetermined value.

7. A filling machine as claimed in claim 4 and substantially as hereinbefore described.