Ratios

[Jeff 232]

All right need your help all you math people. Now please try to explain it so I can understand it.

I have a local company JBS Industries that sells different concrete cleaners or products that can used for concrete cleaning/degreaser. They sell to PW companies but most of there products are for carwashes and Airport run ways.

I'll save a good amount of money on chems & shipping if I can explain to them the ratio Im getting out of my xjet

I use a 5.6GPM machine with a M5 Xjet, but instead of 3/8th hose on Xjet I use a 1/4 inch hose. Im not sure how to ask or even what Im asking. But what is the ratio of water vs chem coming out of my 1/4" Xjet and what else should I be thinking/asking

Now I could just buy these chems from JBS and just try trial & error but Id like to be able to figure and tell JBS what ratios I need and am working with

Now be easy with me Im not real good at this kind of math at all.

I know you all are saying what a dumbass and what the heck is he doing in a biz that uses chems, but bare with me, got to learn sometime:dunno:

Thank you

JL

[bforbis 14]

Jeff,

I will try to take a stab at it. The relative pressure draw the line experiences call it Delta P.

Area of the inside diameter A(id)

radius= r

assume the inside diameter of respective hoses are 3/8" and 1/4" or 0.375" and 0.25" respectively. The relative difference in diameter change is what is important. As we are to determine the relative difference in Delta P between the two hoses.

The radius of each is half that 0.1875" and 0.125"

Assume that force is constant (no changes).

pi= 3.14159

P= Force/Area

A= pi*r*r

3/8" hose= A(1)= 0.1104 in^2

1/4" hose= A(2)= 0.049 in^2

0.1104/0.049 = 2.25 (approx twice the Delta P draw using the smaller hose, theoretically)

There is a dimenishing return on reducing or enlarging the hose diamter, that deal with viscousity of fluid, length of hose, restrictions etc and other variables. Actual results would be something less than theoretical.

I hope this helps... it is a quick "BALLPARK" explanation

[bforbis 14]

*****Made a slight miscalculation in above formula.

The approx difference in chemcial as a result of the Delta P from the smaller hose would be more like.

(0.1104-0.049)/ 0.1104 = 0.556 or about 55% more chemical for the increase draw through the hose.

[Larry B 55]

You might try the laymans way as well. Take a container that has marks on it of known quantities, insert M5. Run your machine into a measurable but larger container and figure out how much liquid you had in the end container and how much you drew out of the other container with your xjet. Divide the numbers and you have a ratio.

You can see some variance depending on the viscosity of your liquid.

[Jeff 232]

Jeff,

I will try to take a stab at it. The relative pressure draw the line experiences call it Delta P.

Area of the inside diameter A(id)

radius= r

assume the inside diameter of respective hoses are 3/8" and 1/4" or 0.375" and 0.25" respectively. The relative difference in diameter change is what is important. As we are to determine the relative difference in Delta P between the two hoses.

The radius of each is half that 0.1875" and 0.125"

Assume that force is constant (no changes).

pi= 3.14159

P= Force/Area

A= pi*r*r

3/8" hose= A(1)= 0.1104 in^2

1/4" hose= A(2)= 0.049 in^2

0.1104/0.049 = 2.25 (approx twice the Delta P draw using the smaller hose, theoretically)

There is a dimenishing return on reducing or enlarging the hose diamter, that deal with viscousity of fluid, length of hose, restrictions etc and other variables. Actual results would be something less than theoretical.

I hope this helps... it is a quick "BALLPARK" explanation

As my 3 year old says "HUH". Do you know who your talking to "ME" Better known as Jethro Bodine, Before I decided I was going to be a pressure washing contractor, I was thinking about being a Double Knot Spy 007. LOL

Thanks Brent, its not you its me

Larry I'll try that thanks

[CCPC 26]

As far as I know from what I've read, the x-jet always pulls a steady 2.5gpm. I'm also pretty certain that with an x-jet engaged to pull liquid it either pulls at 2.5, or its not pulling anything. You know when your using the x-jet and you get a little to high off the ground from the chem supply it starts to pull chem in pulses, well its either going to do that, not pull anything, or pull chem smoothly which will give you a garuntied 2.5gpm.

The rest should be pretty easy, you have a 5.6 gpm machine, and (when your pulling chem smoothly through your M-5) your m-5 is pulling 2.5gpm. figure your ratio from there, which should be a little over a 2:1 ratio, as 2 parts being water, and one part being chem. a total of around 3 parts. I think I did that right?

I forgot to add, my thing about how the x-jet pulls was merely to point out that I don't think it matters weather your using 1/4" hose or 3/8" hose, as long as your still maintaining a smooth pull (i.e. no pulsing or stoping) your getting your 2.5gpm.

[Ron Strickland 14]

The ratios are the same in that intake hose barb is 1/4" ID

[RyanH 14]

I forgot to add, my thing about how the x-jet pulls was merely to point out that I don't think it matters weather your using 1/4" hose or 3/8" hose, as long as your still maintaining a smooth pull (i.e. no pulsing or stoping) your getting your 2.5gpm.

Not quite. The 2.5 gpm most likely is a nominal value with very few constraints.

The Xjet operates like this:

As your water (pressurized from the pump) flows through the Xjet, it passes perpindicular to the draw tube port. Without going into too much detail, the fluid creates a low pressure area at the port opening. To verify this, put your finger over the port inlet on the Xjet while the wand trigger is pulled and water is flowing, you will feel the port "sucking" on your finger (actually, it is the hydrostatic pressure of your bodily fluids pressing towards the low pressure opening, but whatever).

This low pressure area is at a lower pressure than atmospheric pressure. From this point, the Xjet functions exactly as a straw in soda. The pressure differential is such that fluid (water, air, bleach, etc.) will flow from the area of "high" pressure (the atmosphere) to low pressure (the port inlet). If you attach a hose to the inlet and drop the other end into a bucket that is open to the atmosphere, the Xjet will "draw" the chem in.

Here's the kicker: the low pressure point created by the flow is determined only by the fluid velocity (at 5.4 gpm through an Xjet orifice of 3/16", that's a velocity of about 45162 in/min, or 43 mph. This velocity is constant. The pressure is constant. Atmospheric pressure is constant. The difference between atmospheric pressure and the low pressure in the Xjet is a pressure differential. This is constant.

The flow of the fluid through the tube is dependent upon several things. Among these are:

the pressure differential, which is constant

fluid viscosity (water, bleach, soapy water, etc. all have different viscosities). 12% bleach will be more viscous than water and will flow at a lower rate.

XJet tube properties (inner diameter, wall roughness, length, number of turns, bends, height, etc.). This directly affects the friction on the flow of the fluid, which is related to the viscosity. The more constricted the tube is (smaller diameter), the harder it will be for the fluid to flow through it. The more bends in the tube or changes in direction the fluid has to flow, the slower the fluid will flow. Changing the exit height of the tube (up on a roof, for example) will increase the gravitational resistance on the fluid. All of these resistances to flow add up to an overall "pressure drop." Try blowing through a coffee stirrer and a 1" PVC pipe...which one is "easier?" Your lungs create the same amount of force, but the stirrer will create a larger pressure drop and reduce the flow dramatically.

When you create pressure drops, this affects your differential pressure. With no pressure drops, you get ideal flow. With lots of them, you get no flow. All of us operate somewhere in between.

So, that was a long way of saying that your draw will never be constant. You will affect your flow by changing your Xjet hose length, wrapping it in a coil, etc. But changing from a 3/8 to a 1/4" hose will offer the greatest change and will guarantee that you will not get the same flow from a 1/4" as you would a 3/8". The recommendation of pulling from a bucket into a barrel is the best.

[william gurley 14]

Simple Solution put a 3/8ths hose on and be happy.

[bforbis 14]

Jeff,

You know i get hung up on the proving the math thing sometimes and completely miss the most basic part of the question/probelm and putting the answer in realistic terms. Sorry about that Jeff!!!

Ron wrote:

The ratios are the same in that intake hose barb is 1/4" ID

You may create more draw, but the I forgot abou the size of the id of the barb never changed.

Ryan wrote:

Try blowing through a coffee stirrer and a 1" PVC pipe...which one is "easier?" Your lungs create the same amount of force, but the stirrer will create a larger pressure drop and reduce the flow dramatically.

This is essentailly the same, although magnified version of changing from 3/8" to 1/4" hose, Still as Ron wrote, the id of the barb never changed..

Length of the hose will impact the flow and can only be determined experimentally, but that is splitting hairs even more.

The viscousities of most liquids you will be using, although technically vary, are not significantly different to make a measurable difference.

Larry, had the best bottom line answer......Put some stuff in a bucket and test it out. This will change if you change length of hoses or any other restriction added.

[Littlefield 65]

Or get a gas powered pressure pump that has viton seals and will put out 2-4 gpm of any liquid you want, only thing is you have to have a mixing barrel. This allows you precision chem application and mixing, and lots of power for getting the chems where, and only where you want them. Best part for me, no math....:)

[aquabob 14]

jeff, what ratios are you trying to get with the chems you are using?

[aquabob 14]

Or get a gas powered pressure pump that has viton seals and will put out 2-4 gpm of any liquid you want, only thing is you have to have a mixing barrel. This allows you precision chem application and mixing, and lots of power for getting the chems where, and only where you want them. Best part for me, no math....:)

you can do that, but you can also take advantage of the suction from a self priming chem resistant pump.

build a manifold on the suction line and use stainless needle valves to gate the draw from the chem tanks.

i switched to this way of getting chems in i like it alot better than using injectors. only things is you have to measure your draw and make your own increments. takes some doin to figure the ratios but very smooth. mine works great for ratios between 1:6 and 1:20 with 1/4" needle valves on a 3/4" suction line. with larger valves 1.1 would be possible.

this will eliminate the need to pre-mix and gives you control over the ratios on the fly, rather than being stuck will the pre-mixed ratios in the tank.

[Jim Carroll 14]

Jethro the ratio from your xjet open is around 2:1, 2 parts water to 1 part chemical. You can change this using the proportioners. I always use the proportioners instead of bucket mixing. When I used their truck wash I used the proportioner that gave approx. 40:1 ratio. I think this is what you are asking. I know steve's website has a proportioner chart that I think will help you.

[Jarrod 22]

Great, now I have a headache!

[One Tough Pressure 580]

The ratios are the same in that intake hose barb is 1/4" ID

And what happens when you remove the sleaved barb made for proportioners by drilling out the barb to allow for maximum inner diameter?

Yes, I need to test mine for actual ratio's, but what are the limits of the XJet itself?

[Jim in NJ 64]

Try blowing through a coffee stirrer and a 1" PVC pipe...which one is "easier?" Your lungs create the same amount of force, but the stirrer will create a larger pressure drop and reduce the flow dramatically.

that may be true but the xjet is sucking and it is easier to suck coffee through a regular straw then to try to do it through a 1" tube...

[weaselcossey 14]

Try blowing through a coffee stirrer and a 1" PVC pipe...which one is "easier?" Your lungs create the same amount of force, but the stirrer will create a larger pressure drop and reduce the flow dramatically.

that may be true but the xjet is sucking and it is easier to suck coffee through a regular straw then to try to do it through a 1" tube...

Someone didn't pay attention in science class. There is no 'suck'. Suction is created by 'pushing' air to create an area of low pressure, as explained earlier. Think of a shop-vac, it blows air out one end, creating an area of low pressure inside the vac, air in the atmosphere is then pushed into the other end which usually has a smaller tip at the end of a hose. I say 'pushed' because the vac doesn't pull the atmosphere, the atmospehere equalizes the area of low pressure inside the vac which is continually being blown out the other end for constant suction. The smaller tip creates more suction at the tip.

An area of pressure, lower than the pressure in your 5er, is created in the xjet. As a result, the liquid in your 5er is pushed, by the atmosphere, into the area of low pressure inside the xjet. This low pressure area is continually recreated, constantly repeating the process. Its all about atmospheric pressure, this suction stuff. Always makes itsef equal. Stick a needle into a balloon, POP, all the air inside is released to an area of lower pressure, the atmosphere. If this was a helium filled balloon, the results would be much different. This is related to density and such. If your 5er is full of molasses, the results will be much different.

Moral: Use the right proportioner for the recommended ratio. No mixing required, someone who manufactured the xjet already figured all this stuff for us, and was nice enough to make little proportioners color coated for easy reference. If they had only gave us a way to keep up with them.....