pump on and off or electric ball valve?

[Anonymous]

Any chance you could post a link to where we can find a pneumatic valve? Looks like a great idea.

It is a new product which will be first shown in the coming AQUARAMA 2005 in Singapore on 26th May,05. A description leaflet on the system is attached.[/quote]

Well I'm impressed if it works like it says it does. Just so I'm clear, the air pump is not actually injecting air into the water right? It's just pressurizing the line to operate an on/off valve right?

But how is this any different from a series of electronically controlled solenoid valves? How monstrous of an air pump would one need to control, say, 4 1" valves and the pressure behind them?

 

[Anonymous]

Pneumatic ball valve is regularly used in process control. They usually use air compressor for the job to work. Other driving options besides electric motor, pneumatic, are manual (doh!) and hydroulic motor. Like many things in this hobby, we just use technology from other field for the application.

 

[TL]

Yes, the air pump is not actually injecting air into the water. An ordinary air-pump for aquarium use of around 2.5L/min is more than enough for a 50mm dia. pipe. Differences between solenoid valve? Just consider the cost and use of metals of solenoid valve, the hazards when electricity is being used near or within water and the size of pipe they can control.