Morning everyone,

I'm working on building a malting machine (see the project here http://osuminimalter.weebly.com) and I need to purchase some valves for flow control. I have a National Instruments current output module that can output 0-20 mA or 4-20 mA.

I need to be able to control the flow rate of a hot water stream, which will mix with a cold water stream to attain the desired temperature. I also need to control the flow rate of steam, supplied at 80 psi, going through a heating coil. I'm having trouble finding a valve that fits my needs and finding accurate pricing data.

Pipe size for both water an steam will be around 1". So far all I've found is the ASCO posiflow proportional control valves. Do I have any other options? What do you think I will be spending per valve?

 

http://www.magnatrol.com/

 

Thanks, but it doesn't appear that they have proportional control valves, only standard on/off.

 

You might try some HVAC people, like Barber-Colman (part of Invensys now I believe), Johnson Controls, Siemens HVAC division and so on. They tend to have proportional mixing and diverting valves as well as proportional two-way valves, which is what you need, fairly inexpensively compared to an industrial type product.

The thing you'll have to watch for is the control signal. HVAC controls tend to use a bunch of weird signals that we don't use in industrial stuff, but if you look you can find some that will do 0-20 and 4-20. I think they're available both because building stuff is sometimes controlled by industrial automation controllers, and I think some of the native stuff uses what we'd consider "normal" signals.