Chemical injector placement question

[rholman 14]

i'm new to downstreaming and I just wanted to see what you downstreamers would do. Would you put the injector at A or B? Also, I will be primarily a one-man show at 8gpm. The shutoff valves and tee are for those times when i bring a helper and we can shift to 2 guns at 4gpm. Would you use 1/2" jumper hose from the PW to the tee? Or is that not necessary? Also, i'm assuming that it would be impossible(with this setup) to downstream with one gun and rinse with the other, but please correct me if I am wrong. I ordered a General Hi-Draw injector from Bob at pressuretek in case that info helps.

[rholman 14]

Let's try 4 choices instead. I'm thinking it might not be a bad idea to keep the chemicals further away from the shutoff valves(for longevity). I'm thinking C! What do you think?

[ezelder 14]

I am thinking one at C and one at D both. That would give you the ultimate in flexibility. If you have two on hoses, one could apply one could rinse. Both could apply and rinse. Both could rinse. One could use one chem and the other use a different chem.

Thats the only thing that makes sense to me. :-)

[ezelder 14]

Oh, I personally would feed the tee with 1/2. It might not make a noticable difference, but every little bit helps and even if it doesn't make any difference, it wo't cost you much more.

[rholman 14]

thanks Eric....That is a great idea to have 2 injectors. And I agree with the 1/2" jumper hose....I have doubted my decision to go with 3/8" since day one. I can justify getting 1/2" because I can keep the 3/8 for a "backup".

[ezelder 14]

thanks Eric....That is a great idea to have 2 injectors. And I agree with the 1/2" jumper hose....I have doubted my decision to go with 3/8" since day one. I can justify getting 1/2" because I can keep the 3/8 for a "backup".

The doubt you created alone is enough reason that I would change it. If you do not have 100% confidence in you rig, it will trickle down to your work.

[FCPWLLC 233]

I am thinking one at C and one at D both. That would give you the ultimate in flexibility. If you have two on hoses, one could apply one could rinse. Both could apply and rinse. Both could rinse. One could use one chem and the other use a different chem.

Thats the only thing that makes sense to me. :-)

That's exactly where the DSer's need to be. I would also make sure they are Quick connected for easy/quick replacement.

[rholman 14]

good thinking...i will definitely use quick couplers on the injector. How long do they last anyway? What are the tell-tale signs it's "going" bad?

[MMI Enterprises 289]

..please confirm back after it done and let us know how it all works out....

Wondering if yer going with quik connect spray tips and thinking about halfing their sizes for both high pressure rinse and then also the low pressure DSing?

Also, are you going with 4gpm DSer's if ya go with two?..hows that gonna work for ya when single wand spraying? Always been interested in these multi venturi ideas..

[rholman 14]

i gotta admit I didn't think about that. I got the injector today and I installed one because that's all i had ordered before i posted this thread originally. I got the 5-8gpm version. Since they are relatively cheap should i get 2 lower gpm models? I have 3 turbo nozzles (8gpm, 4gpm & 4gpm) for when i switch from 1 gun to 2 guns, but do injectors work along the same lines. i would think so. Also, what if I just use a 4.5 nozzle with a dual lance with my 8gallon machine....will I get even better concentration with my 5-8gpm injector?

[ezelder 14]

..please confirm back after it done and let us know how it all works out....

Wondering if yer going with quik connect spray tips and thinking about halfing their sizes for both high pressure rinse and then also the low pressure DSing?

Also, are you going with 4gpm DSer's if ya go with two?..hows that gonna work for ya when single wand spraying? Always been interested in these multi venturi ideas..

Here we go again. . :)

ACtually you bring up a valid point. INitially I was thinking he was taking two 4gpm pumps running them in parallel to get 8gpm. But no, he is taking an 8gpm and splitting it to what would logically be two 4gpm wands.

There are all sorts of issues here.

1) If you have two wands going, they are going to fluctuate between 4 and 8gpm, depending on if both triggers are pulled or not. This can make tip sizing impossible. If you are tipped for 8gpm, you are golden, until the other wand kicks in, then you are going to drop to a lower pressure spray pattern from an oriface that is too large for the flow. You can take that and run with my thought pattern. If you are tipped for 4gpm, you will reduce your flow, but is it possible to load your pump with too much back pressure?

2) If you put 4gpm injectors on there, you are fine if both are running, but if you run by yourself, you may never be able to get the injector to draw running 8gpm on a single wand.

3) what if you are using both wands and doing more delicate work. Impossible with each wand being on and off and hosing up the flow an pressure of the other.

Just some thoughts I had. I don't have expirience splitting a higher flow pump into two lower flowing wands, so I do not have any practicle application to apply to this assumption. But I would love to hear what someone who has "been there, done that" would have to say.

[rholman 14]

I've ran 2 guns off an 8gpm machine in the past and you can definitely tell when the other guy lets off the trigger. I will play around with it and let you know what i find out. I was trying to shorten the learning curve on DSing part of it. I am going to guess that I should just stick to 1 injector and call it good. Deck cleaning with 2 guns is really most practical on the flatwork part. It is frustrating to do spindles and have your distance set and pressure and then the other guy lets go of his trigger. As far as tip-sizing....4.5's on each gun...and dual lances. that way i can turn the handle instantly to adjust the pressure when the other guy lets off and vice versa.

The beauty of these forums is that you can bounce ideas off others before you go out and waste time on the jobsite. Thanks for the info!

[MMI Enterprises 289]

Eric,

I know you are better able to explain issues that could be involved so I am good and happy with you composing it. I too am awaiting the proper way to go about the dual wanding and then secondarily, but most importantly to me, the DS issues of multi DSing. I just know if you were to combine the outputs after splitting and DSing that at some point no gains will be had in the total amount of chem being drawable. Something to do with head pressure, back pressure, and energy losses.

My feeling (brain is mush again after thinking on wood for the last hour) is that the 8gpm trying to go through just one 4gpm tip is going to set off the unloader. Thinks I heard some mention one time or another about using two unloaders..Where's the experts? they come here anymore?

[rholman 14]

is this some kind of ghost town? lol

I have witnessed first-hand that when you have an under-sized tip that the rest of the flow goes through the bypass hose into the ag tank. I don't however know whether that is bad for the unloader or not. I actually remember like 10 years ago when i first learned about the bypass going into the tank, that this PW company told me that you should set your unloader to the point that when you have the trigger pulled that there should be a "slight trickle" of water going through the bypass hose back into the tank. Now, was that a load of BS? I don't know. They told me that it cuts down on wear and tear from switching back and forth from bypass to full pressure by keeping that bypass open a "little". I would be really interested to hear if anyone else follows that advice.

[ezelder 14]

Eric,

I know you are better able to explain issues that could be involved so I am good and happy with you composing it. I too am awaiting the proper way to go about the dual wanding and then secondarily, but most importantly to me, the DS issues of multi DSing. I just know if you were to combine the outputs after splitting and DSing that at some point no gains will be had in the total amount of chem being drawable. Something to do with head pressure, back pressure, and energy losses.

My feeling (brain is mush again after thinking on wood for the last hour) is that the 8gpm trying to go through just one 4gpm tip is going to set off the unloader. Thinks I heard some mention one time or another about using two unloaders..Where's the experts? they come here anymore?

UNLOADERS. . .hmmmm, I never thought about that. I guess you could certainly use two unloaders to prevent the wands from going over 4GPM. . .

Thanks for the vote of confidence in me, but unfortunately, I just have thoughts and ideas on this topic. I have no practical expirience so no, I cannot better explain it. hmmmm.

I guess the key on the DSers is GPM.

If a 4 GPM DS has 8GPM flow through it, w hat happens?

If an 8GPM DS has 4GPM flowing through it, what happens?

How would you chose which DS to use?

You could theorize that you could put it before the T and rate it for 8GPM. However, running 4.5 tips, you aren't going to flow the full amount. So wo uld they ever work?

If you run 4.0 or 4.5 tips, will you effectively restrict your flow to 4-4.5 GPM? If so than the original thought of mine to put one each at D and C rated at 4GPM would be fine, becuase the tips are going to prevent each segment from flowing more than 4-4.5 GPM.

Don't know. I am just throwing out ideas and thoughts.

[MMI Enterprises 289]

Have heard of undersizing DSer's to get a bit more draw so I could see system with two of the 3-5gpm working fine while under single 8gpm spaying or dual. Not sure how much affect the increased restriction is to the 8gpm of desired power down the line though. Doubt it much though as the orifice difference is like .2 mm between the 3 sizes generally available.

Can't see two of the 5-8gpm version working as good in terms of draw rate as they could have in a single wand system except for fact the 8 rating is at the higher end of the 5-8 rating.

[xpresscleanups 14]

I am having some trouble hooking up my hi-draw injector. I have a DeWalt DS3750 3750PSI 4GPM. I bought mine from Pressuretek. My PW came with a Chemical hose that attaches onto the barbed fitting. I know that the hi-draw injector should be placed after the pump, but exactly where? I wish I could use pics to give a better idea but my camera is not working right now. I am going to be downstreaming. I already have all the other connectors to go with the hi-draw injector.

[We Wash Concrete 64]

Don't use the chemical use that came with the pressure washer that attaches to the barbed fitting before the pump; just forget that stuff is there. If your chemical injector does not have quick connects on it, put those one taking note of which direction the flow is supposed to go, which will be shown by an arrow on the injector. Place the injector on the quick connect coming off the pump, then connect your high pressure hose onto the injector. If you are running long lenghts of hose and you're finding trouble getting chemical at low pressure, you can remove the injector and place it somewhere in between your high pressure hose (like between to stretchs of 100 foot hose).

[Chris S 14]

I am having some trouble hooking up my hi-draw injector. I have a DeWalt DS3750 3750PSI 4GPM. I bought mine from Pressuretek. My PW came with a Chemical hose that attaches onto the barbed fitting. I know that the hi-draw injector should be placed after the pump, but exactly where? I wish I could use pics to give a better idea but my camera is not working right now. I am going to be downstreaming. I already have all the other connectors to go with the hi-draw injector.

If I'm not mistaken, that machine may have the downstream injector and unloader as one piece. I guess if that is the case, you would have to upgrade to a stand alone unloader, and then attach the injector.