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NGP distributes WITT Gasetechnik gas mixers. Gas mixers take standard gases like Carbon Dioxide (CO2), Oxygen (O2) and Nitrogen (N2) and mix them in quantities required by the specific process (eg 70% CO2 and 30% N2). This can be a cost effective alternative to pre-mixed gases.WITT Gasetechnik has mixers to cover the following processes: -
WITT also has a range of MFA analysers for food packaging machines.
Gas filled packages of food are now commonplace and the process, known as Modified Atmosphere Packaging (MAP) or Controlled Atmosphere Packaging (CAP) improves the shelf life and in many cases, the appearance of the foods without the need for chemicals. The main gases used are the most common in the air we breathe. They are Carbon Dioxide (CO2), Oxygen (O2) and Nitrogen (N2).
Mixtures of these gases can be obtained pre-mixed in cylinders but will be more expensive than the individual gases. Mixing as and when required has the added benefit of being able to change the mixture to suit different requirements. While there is the initial up-front cost to consider of integrating a gas mixer into a process, the long term lower gas cost - if seen as a variable cost - will lower the overall unit cost, offering a competitive advantage to the company.
A WITT gas mixer is designed to be as simple as possible but it is important to select the right mixer for your packaging machine. The wrong machine won't cause a disaster but may either slow down the operation or cost more than necessary. NGP encourages you to get in contact with them first to fill out a purposely created questionnaire that will allow the right choice to be selected up-front.
The main points to consider are the volume of mixed gas needed to fill the number of packs being packed and the need for alarm systems to warn of gas supply failure to avoid any risk of putting the wrong mixture in the pack. Calculating the volume is much easier if the product volume is ignored. Product is often irregularly shaped or porous and therefore it is best to err on the safe side, as this will eliminate any risk of the mixer being undersized and slowing down the packaging machine. WITT Gas Mixers produce an accurate mixture provided that the gas does not run out.
If the packaging machine is designed for use by a single operator who is able to keep an eye on the gas supplies then a warning system is not so important. If, however, the machine is running at higher speeds and tendered by a number of operators a warning system is desirable. The system will give an audio-visual alarm and indicate which gas has failed. Depending on the machine design the warning system can be powered from the machine and send a 'stop' signal to the machine to prevent packs being wrongly filled.
Vacuum Packaging machines always need
to be fitted with a receiver. A receiver
is a large pressure vessel (like a tank)
that stores a 'reservoir' of gas already
mixed (downstream of the gas mixer). This
prevents the vacuum damaging the mixer
and ensures that there is always enough
gas available at each cycle since the
receiver can be filled during the loading
cycle. For this reason the receiver should
contain enough gas to completely fill
the packs on one cycle
(Recommended WITT Gas Mixer type: KM100-2MEM
or KM100-3MEM)
Form, fill
and seal machines
These machines do not need receivers but
the mixers should be used in conjunction
with a gas analyser to ensure that the
mixture has replaced the air in the tube.

(Recommended WITT Gas Mixer type: KM100-2M,
KM100-3M, KM300-2M or KM300-3M)
The KD100-1A is a fully-automatic system
to control the flow of a gas or gas mixture
which is being used to replaced ambient
air. The atmosphere is constantly monitored
with an integrated Oxygen analyser to minimise
the required gas flow. Savings of up to
30% are possible meaning that the investment
can be re-couped over a short period.
Applications
Description
The analyser samples the atmosphere via
an integrated pump and the actual Oxygen
concentration is shown on the digital
display. If the actual value is below
the range programmed by the user (eg 0.5%
O2) the integrated control valve opens
and the flow-rate increases. If the value
is too high the gas flow will be reduced
automatically. Any change at the point
of use, for example, a different volume,
is automatically compensated for.
For more information go to WITT