GB2288168A

GB2288168A - Master - slave filling valve system for bottling machine

Info

Publication number: GB2288168A
Application number: GB9406647A
Authority: GB
Inventors: Neil Doggett
Original assignee: BWI DAWSON
Current assignee: BWI DAWSON
Priority date: 1994-04-05
Filing date: 1994-04-05
Publication date: 1995-10-11
Also published as: GB9406647D0

Abstract

A control arrangement for use in a filling machine is comprises at least one master filling valve (3) and at least on slave filling valve (4), the or each master valve (3) being provided with flow monitoring means (6) and associated control means (9). The or each slave filling valve is controlled in accordance with data provided by said flow monitoring means. The flow monitoring means may be an electronic flow meter or a weigh cell positioned between the master valve (4) and a reservoir (2), the flow data being passed to a computer (9). <IMAGE>

Description

MASTER-SLAVE FILLING VALVE SYSTEM The present invention relates to a master-slave valve system, in particular, but not exclusively, for use in a bottle or container filling machine.

In the bottling and filling industry, there is a need to be able to fill bottles and containers to a high degree of accuracy, particularly in the case of large filling plant, where even a very slight overfill per bottle can lead to a substantial erosion of profit margins over an extended period of time.

Filling machines are generally of the rotary type, which comprise a carousel around which bottles or containers travel. Each bottle or container is filled through a filling valve as it travels round the carousel, there being generally as many filling valves as there are bottles or containers on the carousel. In a typical installation, the carousel may have 30 filling valves, each valve communicating with a reservoir of product in a filler bowl.

In simple filling machines, the filling of the bottles or containers is controlled by setting the filling valves to open for a predetermined time, the time being calculated as a function of the volume of the bottle or container and the average flow rate of product through the a filling valve. This method, however, can be wasteful, since it is unable to compensate for variations in product viscosity and density, both of which are generally temperature dependent, nor is this method able to compensate for pressure head changes which may affect the flow rate as the reservoir empties. Furthermore, if the product is not a highly uniform liquid, but contains solid or gelatinous phases (e.g. certain types of yoghurt), the flow rate of the product may be variable.This results in waste, since if the actual flow rate is higher than the predetermined rate, the bottles or containers will be over-filled. On the other hand, if the actual flow rate is lower than the predetermined rate, the bottles and containers will be under-filled, and will have to be withdrawn and topped up in order to avoid eventual customer dissatisfaction and possible breaches of trading standards laws. It is apparent that both these alternatives are undesirable, either wasting product or lowering production efficiency.

It is known to overcome this problem by installing either a flow meter in each filling valve, or a weigh cell beneath the location of each bottle or container on the carousel. A flow meter works by monitoring, generally electronically, the real-time flow rate of product through a filling valve, and is arranged to close the filling valve when the required volume of product has been dispensed. This allows the dispensed volume to be controlled within accurate limits, and enables the time for which the filling valve is open to be varied automatically in order to compensate for variations the flow rate. A weigh cell achieves substantially the same result by monitoring the weight of product dispensed into a bottle or container as it goes round the carousel, and shutting the filling valve once the required weight has been dispensed.

Although the provision of an individual flow meter or weigh cell for each filling valve allows the bottles or containers to be filled to a high degree of accuracy, such an arrangement has a number of disadvantages. A particular problem is that it is cumbersome to initialise each flow meter or weigh cell when recalibrating a filling machine for use with different sized bottles or containers, or when a new product with different density and/or viscosity characteristics is to be filled. Since each flow meter or weigh cell needs to be individually recalibrated, this process can be very time-consuming, leading to a loss of overall plant efficiency since the filling machine will be idle while the adjustments are made.

Furthermore, flow meters and weigh cells are more expensive than straightforward filling valves, and the initial extra outlay for the required number of individual flow meters or weigh cells may not be recouped in product savings for a relatively long time.

According to the present invention, there is provided a control arrangement for use in a filling machine, wherein the control arrangement comprises at least one master filling valve which is provided with flow monitoring means and associated control means, and at least one slave filling valve which is controlled in accordance with data provided by said flow monitoring means.

In a preferred embodiment, the or each master filling valve is provided with an electronic flow meter which measures the flow of product and controls the opening and closing of the valve in order to dispense a predetermined volume of product taking into account viscosity variances and pressure head changes.

Alternatively, the flow rate monitoring means may comprise a weigh cell. The time taken to dispense the required volume is measured, and this data is passed to each slave filling valve, preferably in sequence using a computer to make any necessary adjustments to the flow rates of the individual slave filling valves.

Advantageously, a filling machine provided with the master-slave valve system of the present invention will be provided with more than one master filling valve, each of which will provide control for more than one slave filling valve. For example, on a 30 valve machine, 3 master filling valves may each control 9 slave filling valves.

It will be apparent that in addition to providing relatively high filling accuracy at a relatively low cost, the present invention allows recalibration of the filling machine to be carried out. In the example given above of a 30 valve machine, only the three flow rate meters on the three master valves would need to be recalibrated for filling containers of a different volume, as opposed to the 30 flow rate meters which would need to be adjusted on a filling machine of the prior art. Much time in which the filling machine might otherwise be idle is therefore saved, resulting in increased production efficiency.

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made by way of example to the accompanying drawing, in which there is shown a filling machine comprising a carousel 1, a filler bowl 2, and a number of filling valves, of which only a master filling valve 3 and a slave filling valve 4 are shown. The filler bowl 2 is kept supplied with product via a supply line 5.

A flow meter 6 is provided between the master filling valve 3 and the filler bowl 2, the flow meter 6 being arranged to measure the flow rate of product 7 into a container 8. Flow data from the flow meter 6 passes to a computer 9, which is programmed to calculate, using the flow data and preset volume data, the time for which the master filling valve 3 should be open in order to fill the container 8 with a required volume of product 7. The computer 9 is arranged to control the opening of both the master 3 and the slave 4 filling valves in accordance with this calculated filling time, with small adjustments being made to take into account any different flow characteristics there may be between individual slave filling valves 4.

Preset volume data may be entered centrally into the computer 9, which enables the filling machine to be easily recalibrated for different container 8 volumes.

Claims

CLAIMS:

1. A control arrangement for use in a filling machine, wherein the control arrangement comprises at least one master filling valve which is provided with flow monitoring means and associated control means, and at least one slave filling valve which is controlled in accordance with data provided by said flow monitoring means.

2. An arrangement as claimed in claim 1, wherein said flow monitoring means comprises an electronic flow meter which measures the flow of a product through said master filling valve and controls the opening and closing of the valve in order to dispense a predetermined volume of product, taking into account any product viscosity variances and pressure head changes.

3. An arrangement as claimed in claim 1, wherein said flow monitoring means comprises a weigh cell.

4. An arrangement as claimed in claim 1, 2 or 3, wherein said associated control means is arranged to measure the time taken to dispense the required mass or volume through the master filling valve, and to control each slave valve in accordance this measured data.

5. An arrangement as claimed in claim 4, wherein said associated control means is arranged to operate each slave filling valve in sequence using a computer to make any necessary adjustments to the flow rates of the individual slave filling valves.

6. A control arrangement for use in a filling machine, substantially as herein before described with reference to, and as illustrated in, the accompanying drawing.