Soap Injector physics

[814jeffw]

Hey Pat, I like that configuration better as well,..the straight run when running full flow is a good idea. Good thinking!

Jeff

 

[Patrick Harding]

"That is good info, but if we aren't using a shutoff, how much flow do we lose if the hose is placed in a bucket of rinse water, or, in a pinch, simply pulled out of the soap completely?"

If i'm understanding you correctly, you shouldn't lose much if any significant flow by placing your hose in a bucket of water or just pulling it out of the chem. You would increase flow and pressure by removing the injector but you wouldn't lose flow by removing the chemical feed to the injector. I am assuming your talking about a downstream injector.
-Pat

 

[Pat Norman]

By bypassing the injector my flow and force is MUCH greater PLUS my pump and motor is not working near as hard. I will go back out in a while and take a video to demonstrate the fact. It is just no comparison on my 8 GPM machine between the greater flow when bypassing the injector.

 

[Patrick Harding]

I'm curious how the internals of soap injectors work. Is there a minimum pressure differential between the spray nozzle and the nozzle inside the injector to cause a draw? The reason I ask is because I'd like to know if I can get a downstream injector to work on a 4.5 gpm pump with a maximum PSI of around 500. I think the largest rated soap injector has a 2.3 nozzle inside of it which is .091". According to the nozzle chart this is equivalent to a size 13 spray nozzle. The chart says that this will produce 500 psi at 4.6 gpm. So if I use a size 30 soap nozzle on the wand, that pressure would be about 100 psi. Is the 400 psi difference enough to cause the venturi effect?

On a related note, I have a 5.5 gpm pump on a 5.5hp engine (max psi about 1100) for soft washing. It will downstream great but my xjet won't draw with it.

I don't know if your set up will allow it but something that might work for you is to use a 12v pump to push the chem through the down streamer. We do this with our pressure washers and it allows us to get fairly strong mix with a lot of flexibility when it comes to hose length and nozzles. We use a 2.1gpm shureflo to pull the chem from a tank and push it through the down streamer.

 

[Rance]

Here is mine. I would prefer SS tee's but my local supplier only has tee's up to 150 PSI. So i used galvanized tee's.

 

[GrassButler]

Here is mine. I would prefer SS tee's but my local supplier only has tee's up to 150 PSI. So i used galvanized tee's. View attachment 28555

I like the gallon milk jug Rance... Shine??? Yellow lightning?? lol!

 

[Rance]

I like the gallon milk jug Rance... Shine??? Yellow lightning?? lol!

Had to have a pump up yesterday so I had to mt the F9 into a milk jug. Bought 2 more pump ups today. Gotta get rid of that milk jug.

 

[GrassButler]

Lol.... just busting your milk jugs! Gotta make do when your on the road!