Downstream calculations

"Red"

"Red"

Graphic Designer
I was out this morning measuring the throughput of my 20% DSer. Per my calculations, I'm only getting approximately 10%. Can someone verify my math?

The DSer took 140 seconds to pull 1 gallon (GPS = 0.00714 = .43 GPM / measured)

The pump puts out 4.5 GPM (GPS = 0.750 / measured) but it's only rated for 4 GPM (good or bad?).

I subtracted .43 from 4.5 to get 4.07 GPM from the pump (the balance comes from the DSer).

I then divided 4.07 by 4.5 to get .9048 (or 90.5% from the pump). The balance is 9.5% (from the DSer).

* GPS = Gallons Per Second.
 
I try to keep things done by the minute, it is a little bit easier for me, maybe others too.

Use the length of hose, gun and downstream nozzle you will be using all the time.

I pull the trigger so the chemical hose has some liquid in it because if it is totally empty, that might not give you a true reading for the amount of chemical pulled, at least this is how I do it.

I use a gallon measuring jug and look at the watch and when the second hand is on zero (digital) or on 12 then pull the trigger and when the minute is up, let go of the trigger, pull the chemical hose out of the jug and see how much water is gone.

Multiply the gpm's of your machine by 128 (ounces) so you have the info in ounces.

Then divide and you get the ratio of your injector, using your hose, gun and nozzles. What the manufacturer says it will pull is usually different from what you actually get.

Ex. 5.6gpm x 128 (ounces) = 716.8
Divide that by what your injector pulled Ex: 64 ounces so 716.8/64 = 11.2 (ratio)

This is how I do it, I could be wrong.

Like most others here, I just downstream, get the job done and move on, don't over think this stuff because it really is not rocket-science.

There will be jobs where you need a stronger mix or your mix works fast, that is based on the contaminants on the surface, not some numbers someone said on the internet, some numbers some college guy says it needs to be this ratio or that ratio or anything else, it needs to be as strong as it needs to be.

If your injector does not pull strong enough and you are using straight mix, then time for a different injector, smaller orifice, hit it multiple times or go with a chemical sprayer. You don't need a 3' x 4' chart in your truck showing ratios for this and that, just go and Git-R-Done. hahahahaha j/k
 
It's not rocket science but there is science (and math) behind every thing we do in this business. The more you know the better your end result and if your going to have a successful business you need the best end results you can possibly obtain.
 
4.5 (GPM) * 128 = 576 (ounces)
576 / 128 (ounces drawn) = 4.5 (ratio) - I intentionally pulled just 1 galllon of make believe mix
DS draw = 18% (closer than my calculations and easier to calculate too)

Thanks.
 
Get a gallon jug with water in it. Start your machine without a gun get 2 or 3 5 gallon buckets. Drop your chemical hose in the jug at the same time you hold your pressure hose over the first bucket with the next one beside it. When the jug is empty see how many gallons you have in the buckets. If you have 2 buckets full of water then you have a 10:1 ratio, 3 buckets and you have a 15:1. Hope this helps you out.
 
Just drop it in the tank and spray! :)
 
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