| 摘要 |
A bag of plastics film material which is impervious to air, for storing e.g. lucerne haylage, wine, beer, cheese, comprises integrally formed venting means adjacent one of the margins of the bag, said venting means comprising a passageway 13 formed between opposed wall portions (20, 21, Fig 2, not shown) of said walls 11, (12) a first opening 16 for placing said passageway in gas flow communication with the interior (17) of the bag, and a second opening 19 spaced from the first opening for placing the passageway in gas flow communication with the atmosphere, whereby gases, such as CO2 released during fermentation, in the bag interior are able to escape to atmosphere through said second opening 19 via the passageway 13 but the ingress of air/oxygen from atmosphere is inhibited by virtue of the sealing effect created by the drawing together of the contiguous surfaces of the opposed wall portions (20, 21) when the bag interior pressure is subatmospheric. The passageway 13 is defined between welded bead seals 14, 15. |
