| 摘要 |
The present invention refers to a mechanism required to maintain the inner pressure in one or two balloons of blown-plastic film by means of a circular-shaped die useful for films, wraps and packings. The mechanism consists of a transparent water tube having a dark float which is monitored by a photocell, where in the presence of any inner pressure variation, a valve for automatically compensating said variation is electrically activated by said photocell. The mechanism guarantees the stability of the balloon width without requiring the presence of an operator, allowing the second balloon to be independently controlled for the same purpose. The present invention is simpler than systems currently available on the market, thereby being more affordable and easily maintained. The accurate degree of the inventive mechanism is higher than that of the state-of-the-art.
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