| 摘要 |
PURPOSE:To obtain a sealed lead-acid battery with reasonable cost and higher reliability by installing a safety valve made of ethylene-propylene rubber into a valve cylinder made of propylene resin. CONSTITUTION:If propylene resin is selected as the resin material for a valve cylinder, ethylene-propylene rubber among such as, SBR, NBR, ethylene- propylene rubber and isoprene rubber is employed as a safety valve in view of chemical resistance, thermal resistance and high reliability. Accordingly, the interface between the valve cylinder and the safety valve is not decomposited and not stuck thereto, so that constant valve opening-pressure is always obtained. The cost for per unit weight of the ethylene-propylene rubber is almost the same as proloprene rubber, however, specific gravity of the former is smaller than the latter. Therefore, material cost for producing the safety valve of constant volume is cheaper when the ethylene-propylene rubber is used. |
