Monitoring gas pressure during charging of electric storage batteries

摘要

A transducer mounted in a filling and venting aperture of a battery includes a two part body 11 having a chamber 12 containing a diaphragm 13 engageable with an electrical switch 16 controlling charging of the battery. To permit gas escape whilst ensuring sufficient pressure build-up in the chamber 12 the chamber 12 has a bleed hole 19 which communicates with an elongate channel 21 surrounded by a rubber ring 22 having an orifice 24. The ring 22 and the channel 21 together define an elongate passage 23 the effective length of which is adjustable by sliding ring 22 relative to channel 21 to adjust the restriction to gas flow. The channel 21 and hole 19 can be made relatively large so that the body 11 can be moulded easily without the problem associated with the manufacture of a small bleed hole.