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Synergy Between Adding More Production Lines and Mixers are Important
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Synergy Between Adding More Production Lines and Mixers are Important
Good pressure, good production
Ask any expert on Modified Atmosphere Packaging about the key issues for high quality production, and pretty soon the P word is mentioned – pressure. It is vital that the gases entering the mixer are at a good pressure. This is for two main reasons:
- Low pressures cause inconsistencies in the gas mixture – a real problem for quality assurance. This is often seen with a nitrogen generator.
- Low gas pressures cause the packaging line to operate more slowly – nobody wants that!
As you may know, Modified Atmosphere Packaging, or MAP, increases the shelf life of a product and keeps it looking fresh and attractive to the consumer. This is done by flushing air out of the package and replace it with a gas or mixture of gases. Read more about how MAP works in our blogpost.
It is crucial to the process that the gases are in the correct proportions. Any deviation is likely to badly affect the shelf life and put the products – and the brand – at risk.
Increasing production lines
Mark Sawyer
Senior Engineer
Tendring Pacific |
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Mark Sawyer, Senior Engineer at Tendring Pacific, a UK-based company specialising in MAP control equipment, explains how expanding your plant’s capacity can lead to unexpected, and unwanted gas pressure problems.
“Suppose you have your gas system in place to feed five packaging lines and you want to double your capacity to ten lines. When expanding you need to think of these potential issues": |
- If you simply add more lines without thinking about the gas supply, the same pressure cannot be maintained because the gas supply cannot keep up with the demand of the lines
- The pressure will drop
- As the pressure drops it also fluctuates
- This affects the performance of the mixer
- This in turn will produce an unreliable mixture at the packaging machine
- At the same time, the slower flow of gas into the packaging line means that production must also slow down
“Can you see the problem?” asks Mark. “While you have increased the number of lines to increase production, you may unwittingly also affect quality assurance and reduce production.” Read about on-line quality assurance in MAP.
Choose the right gas mixer
So what are the solutions to this problem?
Mark suggest that there are two possible approaches:
- Invest in new gas supply infrastructure: replace the tanks and pipework so that greater pressures is delivered. This is an extremely costly and disruptive option.
- Replace the old mixer with a state-of-the-art ‘intelligent’ gas mixer that can cope with lower pressures and still produce a consistent gas mix. By far the simpler option.
“Traditional gas mixers require quite high pressures for the gas coming into the mixer. Typically this is between 8.5 and 10 bar (bar is the unit in which pressure is measured),” comments Mark. “This is high and can be difficult to maintain. Furthermore, the pressure in the mixer drops typically by about 2.5 bar when mixing. And flow rates out of these mixers are generally limited to around 400 litres per minute. This means that they can find it tough to cope with extra demand.”
Smart MAP mixer
There is however a new breed of high-tech ‘smart’ mixer on the market. This type of mixer works on a very different scientific principle, termed ‘mass flow’.
These mixers have many advantages over their conventional counterparts:
- They are small but have an extraordinarily high capacity: they can pump out gas at up to 1500 litres per minute.
- They can cope with much lower inlet pressures: down to 2.1 bar and up to 10 bar.
- They measure exactly how much of each gas is coming into the mixer and adjust the flow of the gases to ensure the correct mixture
- There is a much lower drop in pressure – a maximum of 1 bar between the input and output gases.
Mark states: “This type of mass flow mixer can cope with low and fluctuating pressures of incoming gases. Furthermore, you can speed up the production process because of the greater supply to the packaging machine.”
Do be alarmed!
The alarm system on the new type of mixer is also more versatile. It is important that mixers alert the operator if there is a drop in incoming gas pressure. Traditional mixers are factory set to do this if the pressure falls by more than 0.2 bar.
The new type of mixer is different:
- The user can set the alarm electronically and select the pressure drop at which the alarm sounds
- This can be done for each gas individually
- This is important because the ‘intelligent’ mixing process can tolerate different pressure drops on different input gases
“Another big advantage of the new type of mixer is that it constantly monitors how much gas has come into the mixer and how much has gone out,” says Mark. “This information is stored, making it useful for auditing and forecasting, as well as monitoring gas consumption.”
And so...
In summary, then, if you add more lines to your MAP production facility it is vital to make sure that the gas pressures are maintained. Bottom line: Choose an appropriate mixer!