Chemical injection question

[lynkage 14]

Please bare with me as I am new at this.

Is it possible to "pump" chemicals into a DS instead of lowering the pressure at the wand.

I do however understand I would most likely want some kind of metering pump to determine exactly how much chem I want in the line.

My goal is to be able to build a manifold that would allow multiple chems to be used with a switch.

Any help would be appreciated

[PressurePros 249]

That is actually a great question. I know you can force feed a downstreamer to increase its flow. I don't know enough about the physics to know how far you can go with that.

[R L S 14]

I am not sure either but you can upstream your chems to apply under pressure if they are nice to your pump, just a thought.

[Paul Kassander 26]

If you want to force chemicals into the line downstream you will need to inject it at a greater pressure than the output of the pressure pump. The downstream injector works by venturi and I am not aware of anyway it inject chemicals DS without an injector, which needs to reduce the pressure to create the venturi.

If you do want to use multiple chemicals with one injector you can do it fairly easy and inexpensive. The best method I found is to use a 3 way ball valve with some hose barbs and chemical line. It is simple and mostly problem free.

If you want to do it with switches the best method I found was to use DEMA valves in a series with various barbs and T's. I found this to be a pain in the ... they would short out or crack in transport, they didn't seem durable enough for over the road. It was a nice system because I set up wires to the gun for switching chemicals, but it proved to be more maint. and expense than it was worth. So I switched back to the manual valve.

[RCBill 14]

When I was building machine controls, I would look to this company for parts. But many times I would just take ideas.

http://www.omega.com/vh/homePC.html

Bill

[lynkage 14]

I was really trying to stay away from upstream injection. My machine has upstream (Landa SGHW 3500-6) and the prob is the unloader has a recirc to the tank. Yea I could put it back to just a loop through the pump but I like having the ability of letting it run without overheating the pump.

I was looking at the DS and yes I would have to have something like a hydraulic pump to be able to overcome the check valve in the DS at high pressures.

I wonder if anyone knows if car washes do it up or downstream?

As far as the manifold I was going to use a Stainless block about 6"X2"x2" and then drill and tap to my needs. That also gives me the option to put flow meters and stuff to determine how much chems are being injected and at what rates.

Please keep the good stuff coming.

[lynkage 14]

This valve from DEMA seems to be the one!!

http://www.demaeng.com/product.php?id=75&catid=28

It will allow chem draw at up to 3000 psi. I ordered one for $75 + shipping of $8.

I will let every one know how it works when I get it!!

[Russ Johnson 141]

Car washes upstream through solenoids supplied by various product tanks. A remote control activating several relays could turn the chems on and off. For that matter, you could remote start and stop the pump with a clutch, turn the burner on and off, and even shut the engine down.

[lynkage 14]

Thanks for your input Russ.

I do like your idea for shutting a clutch off via remote. I hope this valve does a better job than regular DS's.

Shane