| 每个折痕是由塑胶框的PVC片支撑着，以达到特殊的要求。另外风箱两侧外边是由2个或3个不锈钢片保护着，能起到防铁屑和密封的做用。 |
|
Each
of the folding is supported by PVC support so as to achieve
any special reguirements.In addition,the outside is protected
by 2lr 3 S.S.shee,which can prevent iron debris from dropping
in side and serves as a seal. |
