copyright 2009 by automatic test & control limited. all rights reserved.automatic test &...

Copyright 2009 by Automatic Test & Control Limited. All rights reserved.

Form, fill and seal flexible packaging

Low Pressure FeederDevelopment Project

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Standard In-Line Feeder OperationMaximum Speed Sensor

Medium Speed Sensor

Minimum Speed Sensor

Monitoring BeltTransports products towards the metering

belt by running at a relatively high constant speed, slipping beneath the section of the slower moving product

queue formed over it

Metering BeltSets the speed at which the entire product queue

moves, running at one of three discrete speeds determined by which speed sensors are blocked by

the product queue.

Accelerator BeltMechanically geared to the metering belt to pull a

gap between products as they leave the queue

Product SensorDetects individual products and synchronises them with the

downstream infeed. As the products in the queue are touching each other and the metering belt is electronically geared to the

infeed at one product pitch per infeed pitch, after the initial product is correctly positioned subsequent products remain synchronised with minimal corrections allowing high speed

operation



Standard In-Line Feeder Operation

Waiting for Product The metering belt and hence the product queue is stationary while waiting for products arriving on the monitoring belt

Minimum Speed The metering belt runs at the minimum speed when the minimum sensor becomes blocked with products

Medium Speed The metering belt runs at the medium speed when the minimum and medium sensors are blocked with product

Maximum Speed The metering belt runs at the maximum speed when the minimum, medium and maximum sensors are all blocked with products




Pros

Simple, low cost design - 3 conveyor belts controlled by 2 motors and a basic speed control algorithm, controlling product flow by continually jumping between the minimum, medium and maximum speeds as the end of the product queue is detected. The medium speed is set to the nominal product arrival rate with the minimum and maximum speeds setting the range over which the speed can vary.

Cons

Operates over a limited minimum-maximum speed range, typically +/-15% of the nominal product arrival rate, depending on product handling constraints and the time available to make speed change




Push Through As the length of the product queue

increases, the back pressure on the queue also increases due to the faster moving

monitoring belt slipping beneath the slower moving queue. This can cause “push

through” where the entire queue starts moving faster than the metering belt, creating

an un-correctable positional error in the products leaving the queue, leading to loss of

synchronisation with the infeed.

The minimum-maximum speed range can be increased by a combination of the following

Increasing the length of the monitoring belt to increase the distance between consecutive speed sensors, extending the time available to make speed changes.

Increases the back pressure on the product queue due to the monitoring belt slipping beneath a longer queue, making the onset of “push through” more likely.

Increasing the acceleration rate used to jump between speeds, ensuring speed changes take place within the time available.

Rapid speed changes increases the chance of product slipping on the metering belt, making the onset of “push through” more likely.




The onset of “push through” can be minimised by a combination of the following

Using a low friction (slippery) monitoring belt

Belt can be contaminated with product debris, loosing its low friction properties

Using a high friction (sticky or vacuum) metering belt

Belt can be contaminated with product debris, loosing its high friction properties

Increasing the length of the metering belt to increase the static friction holding the product queue at metering belt speed

Increases the overall length of the ILF using more floor space

Reducing the length of the monitoring belt to reduce the back pressure on the product queue

Reduces the distance the distance between speed sensors, decreasing the time available to make speed changes and hence limits the minimum–maximum speed range.



Low Pressure In-Line Feeder Operation

Arrival Rate Sensor Queue Sensor

Monitoring BeltTransports products towards the metering

belt by running at a relatively high constant speed, slipping beneath the section of the slower moving product

queue formed over it

Metering BeltSets the speed at which the entire product queue moves,

running at the average product arrival rate as detected by the arrival rate sensor with feedback correction to keep the end of the product queue around the queue

sensor

Accelerator BeltMechanically geared to the metering belt to pull a

gap between products as they leave the queue

Product SensorSynchronises products with the downstream infeed

using a variable electronic gear, automatically compensating for products that naturally vary in length

due to the manufacturing process (e.g. baked products, which can be over/under sized by as much

as +/-15%), increasing the maximum speed and/or reducing the chance of push through by minimising the

otherwise higher accelerations required to remain synchronised




Waiting for Product The metering belt and hence the product queue is stationary while waiting for products arriving on the monitoring belt

Minimum Speed

The metering belt runs at a variable speed between the minimum and maximum limits while the end of the product queue remains around the queue sensor, making machine speed independent of queue length

Maximum Speed




Simple, low cost design – 3 conveyor belts controlled by 2 motors and a refined speed control algorithm, controlling product flow by monitoring the actual product arrival rate.

Back pressure on the product queue is automatically minimised by maintaining a short queue over the entire speed range, significantly reducing the possibility of “push through”.

Speed changes are carried out gradually using low acceleration, minimising the chance of product slipping on the metering belt, making the onset of “push through” less likely.

Operates over a wide minimum-maximum speed. The maximum speed is set slightly higher (typically 10%) than the maximum product arrival rate. The minimum speed is set as low as possible without causing other wrapping issues, e.g. burning the wrapping material




50%

50%

100%

0%

Wide Min-Max Speed Range

Multi-line application where machines run in pairs, each receiving 50% of production. If one of the pair stops for any reason, the other machine automatically ramps up to take 100% of production until the stopped machine comes back online.




Alternate slugs of products

Alternate products

To prevent slugs of products rapidly increasing queue length and causing push through, an adjustable feature modulates machine speed in synchronisation with products arriving at the end of the queue



New End Seal Technology

For more Information

Email

Please contact [email protected]

Telephone

+0044 (0)141 812 6031

Address

Automatic Test & Control Limited35 Lubnaig DriveLinburn EstateErskinePA8 6AU


mailto:[email protected]

copyright 2009 by automatic test & control limited. all rights reserved.automatic test &...

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