The invention relates to an airtight packaging, such as a bag, drum or box . Such packagings are for instance used for transporting perishable goods such as fruit , meat , vegetables and grains .

Owing to the airtight packaging it is possible to keep the perishable goods in a controlled atmosphere , for instance an atmosphere with a reduced oxygen content , whereby the goods have a longer li fespan .

After filling of the packaging, such as a big bag, with the goods , the air in the packaging is for this purpose replaced with a desired gas mixture , following which the packaging is closed .

It is however possible that , after some time , the desired atmosphere in the packaging changes because moisture and gases escape from the goods into the atmosphere , because the packaging is not fully airtight or because gases di f fuse via the wall of the packaging .

In order to counteract such fluctuations in the desired atmosphere in the packaging it is known to place an absorber in the packaging, which absorbs for instance oxygen and can thereby ensure a desired low oxygen content in the atmosphere over a longer period of time .

A problem is however that , after the packaging is closed, it is impossible to check whether the desired atmosphere prevails , or still prevails after a longer time . The only option is to break the airtightness of the packaging so that samples can be taken of the atmosphere in the packaging . The packaging must then once again be closed airtightly, wherein the atmosphere must be restored or maintained . Such a manner of checking the atmosphere is labour-intensive .

In addition, maintaining a desired atmosphere is only one of the parameters playing a determining role in preserving freshness of the perishable goods during transport . Another parameter is temperature . Although the goods are transported in climate-controlled spaces during transport , it is possible for one packaging of a batch to be subj ect to di f ferent temperatures than another packaging . A packaging positioned next to an access door of the climate-controlled space for instance will be exposed to more temperature fluctuations than a packaging located at the back .

It is thus possible that , after a batch of goods arrives , the goods in the one packaging will be of better quality than in another packaging . It will then be unclear to the supplier whether this di f ference is the result of irregularities during transport or whether the goods already had di f ferent levels of quality at the time of packaging .

It is therefore an obj ect of the invention to reduce or even obviate the above stated drawbacks .

This obj ect is achieved with an airtight packaging according to the invention, wherein arranged on the wall of the packaging is a sensor module which is in contact with the inner side of the packaging via a measuring part of the sensor module , which sensor module comprises :

- at least one sensor, such as a temperature sensor, a humidity sensor or an oxygen sensor, which at least one sensor forms the measuring part of the sensor module ;

- a memory;

- a battery;

- wireless connecting means ; and

- a control powered by the battery, which control periodically reads the at least one sensor and stores the read measurement values in the memory, and sends the measurement values present in the memory to a receiver via the wireless connecting means .

The sensor module of the airtight packaging according to the invention is in continuous contact with the inner side of the packaging, and thereby with the atmosphere prevailing in the packaging, via the measuring part . The control reads the sensor periodically so that a picture is formed of the course of the atmosphere prevailing in the packaging .

When the packaging must be checked during transport , the stored measurement values can be read and further processed in simple manner by wirelessly connecting to the control . Breaking the airtightness of the packaging is therefore not necessary .

It is hereby possible to check all packagings in a batch quickly, and such a check need not remain limited to a single random check .

It is additionally possible using the stored measurement values to deduce at which moment during transport the packagings were exposed to undesirable influences , such as excessive temperatures . It is then possible hereby to determine who is responsible for any possible decay of the goods .

In a preferred embodiment of the airtight packaging according to the invention an opening for introduction of gas is arranged in the wall of the packaging and the sensor module protrudes with the measuring part into the opening and closes the opening .

Known packagings for perishable goods , such as big bags , can be closed airtightly after being filled, for instance by sealing shut the filling opening . In order to bring about a desired atmosphere in the packaging such a packaging is often provided with a separate , closable opening for introduction of gas . Via this opening the air can be drawn out of the packaging and a desired gas can be fed to the packaging . After the introduction of gas the opening for introduction of gas is closed . By closing this opening for the introduction of gas with a sensor module according to the invention existing airtight packagings can be used for the invention in simple manner .

The packaging further preferably comprises a cover for closing the opening for introduction of gas , and the sensor module is preferably arranged on the cover .

After the introduction of gas the cover with sensor module can be placed on the opening for introduction of gas in simple manner, for instance by screws . An additional advantage is that the covers with sensor module can be produced and stored separately from the packaging . The decision to use a sensor module according to the invention need not be made until the packaging is taken into use .

In a preferred embodiment of the airtight packaging according to the invention the at least one sensor is an oxygen sensor, particularly an optical , fluorescence quenching oxygen sensor .

With the oxygen sensor the oxygen content in the atmosphere in the packaging can be measured, and it is possible to track whether the oxygen content is low enough for the perishable goods .

The oxygen sensor is particularly an optical , fluorescence quenching oxygen sensor . Such a sensor can be produced cheaply compared to other oxygen sensors , whereby the invention can easily be applied on several packagings of a single batch to be transported .

A fluorescence quenching oxygen sensor comprises a layer which changes colour depending on the oxygen content , so that a measurement of the oxygen content can be obtained in simple manner with a light or colour sensor . Because the colour-changing layer can be applied by means of printing, the sensor can be produced in cost-ef fective manner .

In yet another embodiment of the airtight packaging according to the invention the wall of the packaging comprises on the inner side an airtight lining .

The airtight lining makes it possible to adapt the outer side of the packaging to other requirements for the packaging, such as strength . The lining then provides for the airtightness of the packaging . A big bag, which usually consists of a woven plastic material , can thus for instance be adapted into an airtight packaging .

In yet another preferred embodiment of the airtight packaging according to the invention a filter layer is arranged around the measuring part of the sensor module for the purpose of preventing direct contact between the content of the packaging and the measuring part .

The filter layer ensures that the gases in the atmosphere in the packaging are able to reach the measuring part of the sensor module , while the filter layer ensures that the packaged goods are unable to come into direct contact with the measuring part and thus possibly interfere with the measurements .

These and other features of the invention are further elucidated with reference to the accompanying drawings .

Figure 1 shows a perspective view of an embodiment of an airtight packaging according to the invention .

Figure 2 shows a cross-sectional view of the sensor module of the packaging according to figure 1 .

Figure 3 shows a schematic representation of the operation of the sensor model of the packaging according to figure 1 .

Figure 1 shows an airtight packaging 1 according to the invention, particularly a big bag with li fting eyes 2 and therein a plastic bag 3 which serves as airtight lining and which is sealed shut on the upper side along an edge 4 after filling . A sensor module 5 is arranged on an opening for introduction of gas .

Figure 2 shows the sensor module 5 in cross-section . Sensor module 5 is arranged on a cover 6 , which cover is screwed onto the opening for introduction of gas 7 which is formed on plastic bag 3 . The plastic bag 3 is surrounded by a strong, woven material 8 from which the big bag is formed .

Sensor module 5 protrudes with sensor 9 into the airtight plastic bag 3 and is surrounded by a porous filter material 10 so that the content 11 of packaging 1 cannot come into direct contact with sensor 9 , but sensor 9 is able to perform measurements of the atmosphere in packaging 1 .

Figure 3 shows a schematic representation of the operation of sensor module 5 . This sensor module 5 has a sensor 9 , such as a temperature sensor, oxygen sensor, humidity sensor or combination thereof , which is connected to a control 12 which is powered by a battery 13 . Control 12 reads sensor 9 periodically and stores the measurement values in a memory 14 .

When the atmosphere in airtight packaging 1 must be checked, a receiver 15 can be used to connect wirelessly to the wireless connecting means 16 , whereby control 12 can send the measurement values stored in memory 14 to the receiver 15 . These measurement values can then for instance be sent by receiver 15 to a central server so that historical data can be collected in case irregularities occur during transport of the goods in packaging 1 .