downstream

[alvaro 14]

Hi everyone, I’m about to start a part-time PW business, but I’m still very green. Until I start reading this boards, the only way I knew to apply chemicals was by upstream and pump up sprayer. I read somewhere that downstream cut a lot with chemicals and improve the life of the PW machine.

How exactly does Down Stream works? How is that done? How does that relies on low pressure to get the chemicals to draw, when you using high pressure in your PW? Any help will be much appreciated. Thanks.

[One Tough Pressure 580]

Downstream is an injector that is places after the pump in any of several positions on your machine.

You can place it just before the burner if you desire hot chemicals, at the hose reel so that chemicals are not going thru the burner, or at the gun so that chemicals only go thru the gun and lance. You have to choose what works best for you on that part.

While your machine is normally run in high pressure mode, in order for the injector to work, you must switch to low pressure, which can be done by changing the tip in the wand, using a dual lance, or by using a roll over nozzle.

The dual lance seems to be more popular as you wash at high pressure, then turn the handle and get low pressure which draws soap. You then close the handle valve, and get high pressure and no soap for a rinse.

[Scott Stone 604]

Downstream is an injector that is places after the pump in any of several positions on your machine. Yep, that is right

You can place it just before the burner if you desire hot chemicals,Or you can let the hot water heat up the chemicals since it is usually a 20% ratio at best, and still do it after the heater at the hose reel so that chemicals are not going thru the burner, Every injector I have seen is on the outlet of the burner. I guess you could put it at the hose reel but I have never seen anyone do it that way or at the gun so that chemicals only go thru the gun and lance. This works, and you will use less chemicals, but you will have to drag around two hoses You have to choose what works best for you on that part.

While your machine is normally run in high pressure mode, in order for the injector to work, you must switch to low pressure, which can be done by changing the tip in the wand, using a dual lance, or by using a roll over nozzle.

The dual lance seems to be more popular as you wash at high pressure, then turn the handle and get low pressure which draws soap. You then close the handle valve, and get high pressure and no soap for a rinse. The injectors work by the Venturi effect, similar to a carburetor. When the Low pressure goes on the pressure in the injector is lower and lets it suck soap.

SOrry, I could not resist.

[Aplus 525]

After I read it a couple times, I understood what Alan was saying. He has a distinct way of describing events.....:)

[beyoungsr 14]

SOrry, I could not resist.

Why would you use less chems if the injector was installed at the gun?

Wouldn't the draw rate be the same at all locations mentioned above?

[One Tough Pressure 580]

Less chems running thru X amount of hose, since it is just at the gun. Also faster to clear soap out of line.

Scott,

If you are trying to say I could of made a shorter statement by explaining carbs, then it may end up being longer as EFI has been the dominant for years now.

[beyoungsr 14]

Less chems running thru X amount of hose, since it is just at the gun. Also faster to clear soap out of line.

Scott,

If you are trying to say I could of made a shorter statement by explaining carbs, then it may end up being longer as EFI has been the dominant for years now.

OTP,

Yeah that makes sense. The draw rate of the injector is the same at either location. You just have to engauge the gun longer to compensate for the hose length.