| 摘要 |
Some paste or liquid products, used as cosmetics and medicines, for example, have to be protected from contact with air. Methods have been developed for vacuum packaging them. These methods are more concerned with eliminating air that may remain in the packaging filled with the product at the time the latter is closed (by welding, by sealed fixing of a dispensing valve, etc). No special precautions are taken during filling of the packaging which is carried out in air and inevitably causes unwanted air bubbles to be trapped. The present method avoids any inclusion of air in the product. The packaging, which consists of a variable volume reservoir, is filled while in its maximum content configuration in an hermetically sealed enclosure that is evacuated. The enclosure is formed by a bucket receiving the reservoir and to which a bell fits in a sealed way. The bell is connected to a system of vacuum pumps and to a store of the product. Communication is established by means of a non-return valve at the outlet of an injector tube. A metering cylinder is used to isolate a volume of product equal to the maximum content of the reservoir R and then to discharge this via a three-way valve.
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