GB2162648A

GB2162648A - Bag testing

Info

Publication number: GB2162648A
Application number: GB08419937A
Authority: GB
Inventors: Anthony Simeon Brittain
Original assignee: HULBRITT PACKAGING SYSTEMS LIM
Current assignee: HULBRITT PACKAGING SYSTEMS LIM
Priority date: 1984-08-04
Filing date: 1984-08-04
Publication date: 1986-02-05
Also published as: GB8419937D0

Abstract

A method of testing bags containing e.g. snack food products and a volume of entrapped air. A first electrical signal is generated representative of a bag volume at a first position 10 and pressure is applied to the bag at at least one further position 12 via pins 18. A second electrical signal representative of final bag volume is then generated and the bag passed as acceptable should the second electrical signal reach a predetermined portion of the first signal. The electrical signals may be generated by potentiometer operatively connected so as to measure the displacement of the central pin 18. <IMAGE>

Description

SPECIFICATION Bag testing The present invention relates to bag testing and in particular, though not exclusively, to the testing of packets or sachets containing snack food products.

Bags filled with snack food products such as potato crisps or chips contain a certain volume of entrapped air which provides some mechanical protection for the crisps or chips. The volume of entrapped air varies from bag to bag and can cause difficulty in setting the bag testing equipment. This can become a particular problem when a bag testing line is used for more than one product.

According to the present invention there is provided a method of bag testing which comprises generating an electrical signal representative of the bag volume at a first position, applying pressure on the bag at at least one further position, and generating an electrical signal representative of the bag volume at a final position, the bag being passed as acceptable should its volume, as measured by the electrical signal at the final position, reach a predetermined proportion of the bag volume as measured at the first position.

The electrical signal generated is preferably a linear one as given for example by the output from a potentiometer. A pin or pins displaceably mounted in a block may cause to be displaced by a bag to be tested, the magnitude of the displacement being used to generate the appropriate electrical signal.

In a preferred embodiment of the invention four positions are provided at each of which a matrix of pins is caused to engage with bags under test, bags being moved from position to position upon a walking beam conveyor. In this embodiment also a further position is provided upstream of said four positions at which bags to be tested are levelled and aligned in a respective well of the walking beam conveyor.

The invention will now be described further by way of example with reference to the accompanying drawings in which: Figure 1 is a side elevational view of a bag testing line showing a first bag volume measuring position and a first pressure position, and Figure 2 is a similar view to Figure 1 but showing a second pressure position and a final bag volume measuring position.

The views of Figures 1 and 2 are to be viewed side-by-side with Figure 1 upstream of Figure 2.

Four positions 10, 12,14 and 16 are illustrated.

Each position includes a 3 x3 array of pins 18 displaceably mounted in a block 20, respective collars 22 serving to limit the downward displacement of the pins. Each block 20 is fixed to a beam 21 which is vertically reciprocal in a stepwise manner.

A walking beam conveyor of known form, shown generally as 24, displaces a bag to be tested from position to position in synchronism with reciprocal movement of the beam 21. A filled bag under test, 26, is received in each of the conveyor wells 28 and the arrangement is such that when a bag is at any one position a set of pins is loaded on to it to apply a loading pressure thereto.

In all positions shown in the drawings, the beam 21 is in a lowered condition with the pins 18 applying a loaded pressure to the bags. At position 10, the central pin 18 is operatively connected electrically to a potentiometer (not shown), the displacement of the pin serving to generate a linear electrical signal which is stored in a memory device. The beam 21 is then raised and the bag indexed to position 12 where the pins 18 once again apply a loading pressure to the bag. At position 12, however, no measurements are taken. Position 14 is identical to position 12 in that the pins 18 once again merely apply a loading pressure on the bag.

At position 16, however, the displacement of the central pin 18 is again measured in the same way as at position 10. The magnitude of the signal is then compared with that of the signal stored in the memory device. Should the second signal reach a predetermined proportion of the stored signal then the bag is passed leak-free and therefore as acceptable.

If desired, a further position, identical to each of the illustrated positions may be provided upstream of the illustrated positions, the further position serving to level a bag in its well 28, so that the bag is then presented in a correct orientation ready for testing.

1. A method of bag testing which comprises generating an electrical signal representative of the bag volume at a first position, applying a pressure on the bag at at least one further position, and generating an electrical signal representative of the bag volume at a final position, the bag being passed as acceptable should its volume, as measured by the electrical signal at the final position, reach a predetermined proportion of the bag volume as measured at the first position.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

SPECIFICATION Bag testing The present invention relates to bag testing and in particular, though not exclusively, to the testing of packets or sachets containing snack food products.

Bags filled with snack food products such as potato crisps or chips contain a certain volume of entrapped air which provides some mechanical protection for the crisps or chips. The volume of entrapped air varies from bag to bag and can cause difficulty in setting the bag testing equipment. This can become a particular problem when a bag testing line is used for more than one product.

According to the present invention there is provided a method of bag testing which comprises generating an electrical signal representative of the bag volume at a first position, applying pressure on the bag at at least one further position, and generating an electrical signal representative of the bag volume at a final position, the bag being passed as acceptable should its volume, as measured by the electrical signal at the final position, reach a predetermined proportion of the bag volume as measured at the first position.

The electrical signal generated is preferably a linear one as given for example by the output from a potentiometer. A pin or pins displaceably mounted in a block may cause to be displaced by a bag to be tested, the magnitude of the displacement being used to generate the appropriate electrical signal.

In a preferred embodiment of the invention four positions are provided at each of which a matrix of pins is caused to engage with bags under test, bags being moved from position to position upon a walking beam conveyor. In this embodiment also a further position is provided upstream of said four positions at which bags to be tested are levelled and aligned in a respective well of the walking beam conveyor.

The invention will now be described further by way of example with reference to the accompanying drawings in which: Figure 1 is a side elevational view of a bag testing line showing a first bag volume measuring position and a first pressure position, and Figure 2 is a similar view to Figure 1 but showing a second pressure position and a final bag volume measuring position.

The views of Figures 1 and 2 are to be viewed side-by-side with Figure 1 upstream of Figure 2.

Four positions 10, 12,14 and 16 are illustrated.

Each position includes a 3 x3 array of pins 18 displaceably mounted in a block 20, respective collars 22 serving to limit the downward displacement of the pins. Each block 20 is fixed to a beam 21 which is vertically reciprocal in a stepwise manner.

A walking beam conveyor of known form, shown generally as 24, displaces a bag to be tested from position to position in synchronism with reciprocal movement of the beam 21. A filled bag under test, 26, is received in each of the conveyor wells 28 and the arrangement is such that when a bag is at any one position a set of pins is loaded on to it to apply a loading pressure thereto.

In all positions shown in the drawings, the beam 21 is in a lowered condition with the pins 18 applying a loaded pressure to the bags. At position 10, the central pin 18 is operatively connected electrically to a potentiometer (not shown), the displacement of the pin serving to generate a linear electrical signal which is stored in a memory device. The beam 21 is then raised and the bag indexed to position 12 where the pins 18 once again apply a loading pressure to the bag. At position 12, however, no measurements are taken. Position 14 is identical to position 12 in that the pins 18 once again merely apply a loading pressure on the bag.

At position 16, however, the displacement of the central pin 18 is again measured in the same way as at position 10. The magnitude of the signal is then compared with that of the signal stored in the memory device. Should the second signal reach a predetermined proportion of the stored signal then the bag is passed leak-free and therefore as acceptable.

If desired, a further position, identical to each of the illustrated positions may be provided upstream of the illustrated positions, the further position serving to level a bag in its well 28, so that the bag is then presented in a correct orientation ready for testing.

1. A method of bag testing which comprises generating an electrical signal representative of the bag volume at a first position, applying a pressure on the bag at at least one further position, and generating an electrical signal representative of the bag volume at a final position, the bag being passed as acceptable should its volume, as measured by the electrical signal at the final position, reach a predetermined proportion of the bag volume as measured at the first position.