摘要 |
A low-pressure balloon, and method of forming same by the steps of: preheat a thin film of thermoplastic polymeric material to a sufficient temperature; forming two halves of the balloon on said thin film of thermoplastic polymeric material by vacuum suction; isolating the two halves of the balloon from said thin film of thermoplastic polymeric material; bonding the two halves together on their edges to form the low-pressure balloon by radio-frequency welding method; and inverting the low-pressure balloon from inside out to turn the rough bonded edge of the two halves into the interior side of the balloon. |