Patent ID: 7824096

Claim:
A transit, concrete mixing vehicle for receiving concrete ingredients, mixing and dispensing concrete comprising: (a) an inclined revolving concrete mixing drum carried on a vehicle chassis; (b) a self-purging auxiliary fluid supply system for supplying unused washout or makeup water optionally including other additives, under pressure, to said concrete mixing drum, said system comprising: (1) a truck-mounted fluid storage tank for containing and supplying said washout or makeup water from said tank to said drum; and (2) an air-operated pump apparatus having a first intake assembly connected to receive fluid from said storage tank and supply said fluid under pressure to a discharge assembly as needed associated with the operation of said concrete mixing drum, said air-operated pump further being configured with a second intake to selectively supply air to an integral purge system for displacing residual fluid in said fluid supply system after use to thereby purge said system wherein said second intake is also operable as a drain.