Directional Control Valves?

Hey All-

I've been away from the forum for some time....life kind of pulled me away! I've been lurking over the past year....I'm currently deployed to Afghanistan and now that I've got time on my hands I've been thinking about upgrading my brew rig.

Anyone have any experience with directional control valves? Apparently they're used in hydraulic applications to move fluids in several directions by using a selector knob. Here's a link: http://www.princehyd.com/Portals/0/products/valves/vls3000.jpg .

Seems perfect for brewing....you could avoid buying several ball valves and essentially switch between different paths for fluids to travel. For example, I envision being able to hook a 4 way valve up to a hose, and by moving the selector lever, I could choose between filling the HLT with filtered water, chilling through a cfc, flushing the whole system for cleaning, or supplying water to an onboard spray nozzle for cleaning out the BK/MLT.

Any ideas as to why this may not work?

Might be tough to find one in a food safe material,

I've seen several being sold new in SS. Unless there's some issue with the gaskets, should be pretty food safe if flushed with PBW, right?

I've been doing a little reading, and I wonder if these require some kind of balancing pressure to keep the incoming fluid from forcing the valve all the way open (and the selector knob all the way out). Seems like it would be pretty sweet to have your water and wort controlled with a selector lever, vs. turning a bunch of ball valves.....

There are 2 basic types that I know about. One uses centering springs on the end of the spool so the spool remains in a neutral position unless the lever is held. This is a momentary valve, as soon as you release the lever the spool returns to its neutral position. The other type has detents either on the spool or the lever which allows the valve to maintain the position the lever is paced in. In either case I dont think the force exerted by the wort would be enough to shift the spool position by itself. I think you have a good idea here as long as you stick with manually operated valves. Solenoid operated valves would have pilot passages that could become plugged with trub or break material.

Edit: check leakage rates on these before you buy. while they are sealed at the ends of the spools to prevent outside leakage, most spool valves use the close tolerance of the spool/bore to seal between the circuits. (They always have a little internal leakage)

Here is a valve by Weatherhead that is probably what you are looking for http://www.grainger.com/Grainger/items/1VRB9?Pid=search. The grainger example was just that, there may be other cheaper sources for the same valve. Here is another option from the Apollo valve line a 5 way ball valve http://www.apollovalves.com/_products/78-124_125/TS_78-124.pdf, you should be able to get these through a plumbing supply house that handles apollo valves.

Man, Kevin, you are a living encyclopedia on process control! You probably have forgotten in a microsecond, more than I will ever know about this stuff.

Thanks, guys....I really appreciate the help. I'm trying to learn more about solenoid operated valves for this very purpose. I'm probably going to convert my rig to all electric...and I'll probably be using the BC-460 controller considering it's a little more than 2 PID's. If you were operating a multi-positional valve like this via solenoid, how would you control it? I think it would be really slick to have both my water and wort controlled by one 4 or 5 way valve each.....

A cheap way would be gear reduction motor, 4 micro switches, 4 relays and a power supply for the motor. A cam disk with one lobe to break switch contacts at correct position and you should be good to go. This is a copy of the Swagelok actuator control, power through the switch to actuator until postion reached, then motor stops, this would eliminate lost position problem and be simple to build. It could be controlled with a single flag and opto coupled switches in series with the 4 relay coils.