| 摘要 |
Plug contg. a porous disc for venting an accumulator casing has a body made of thermoplastic material with a cavity into which the disc is located and sealed by a peripheral burr gouged from the upper parts of the cavity walls by a punch after the surface material of the walls has been thermally softened. The plugs may be made of ABS or polypropylene and the discs of sintered polyethylene or polypropylene. Both heating and forming are pref. effected by a punch of slightly larger dia. than the bore of the cavity where the punch itself is an ultrasonic heating tool, but other forms of heating, e.g. conduction or microwave, may be used where appropriate. Used for mfr. of plugs to vent the casing without allowing interaction between an external flame and a hydrogen atmos. within the accummulator. The base of the plug cavity includes a smaller recess with a lateral passage to the outer atmos. |
