摘要 |
Electrolytic capacitors are provided with a pressure-relief valve which opens if the gas pressure inside the capacitor exceeds a given value to relieve the pressure. In the case of severe electrical overloading, however, the gas-relief passage usually is of insufficient size to prevent excessive pressure build-up, and there is a possibility of explosions. The present invention provides a capacitor in which the pressure-relief valve comprises a venting aperture in a bowl-shaped recess member with the aperture being closed by an elastic member held in compression over the aperture by a thermoplastic strip secured at its ends to the wall of the capacitor housing. The valve is self-sealing for minor pressure increases, but with severe increases a rapid temperature rise of the capacitor roll softens the thermoplastic strip which then allows the elastic member to be blown away so that the aperture becomes directly open to the atmosphere and allows the excessive pressure to be released very rapidly to prevent any possible explosion. |