acoustic telemetry using pipeline

Gents+2
I have an application with a pd pump at the bottom of a hill feeding a tank at the top. When the tank is full I want the pump to stop. Would prefer a level switch in the tank in this case, rather than a float valve/restrictor at tank, pressure switch/accumulator at pump. There is no line of sight so simple telemetry is out and I do not want to run a wire.
Was wondering is anyone makes an acoustic transmitter and receiver so I can sent a sound signal down the pipe through the water from the tank to the pump.

Any leads would be appreciated.

Cheers

Steve Received on Wed Mar 30 17:00:00 2005