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View Full Version : Help on plumbing a spray rig!


fireman1173005
01-17-2009, 02:57 PM
OK I am trying to plumb a skid sprayer and am having trouble getting enough pressure. I have 1" supply line running from my tank to my pump and 1" line from my pump to my reel. I have a centrifugal pump so of course it isn't going to put out as much pressure as a roller pump. I am wondering if I should increase the size of my supple line coming into the pump to say 1 1/2" so I will make sure and bring in more water to my pump than hopefully I am putting out, I think I may be starving my pump. What do u guys think?

Thanks,

Brian:confused:

ted putnam
01-17-2009, 03:18 PM
The supply to your hose reel does not generally need to be as large as the supply to your pump. Do you have a line on the discharge side of your pump set up as "bypass"? That is to say any excess(unused by the hose reel) goes back to the tank hopefully in the form of agitation.

greendoctor
01-17-2009, 03:20 PM
What kind of pump? If this is a water transfer pump, those are not made to generate any kind of pressure. The centrifugal pumps I have seen designated for spraying are good for at least 75 PSI and over 20 GPM. At that rate, you should be able to run a boom or Lesco gun. Check your bypass or agitation valve too. If that is set to dump it all before it goes into your reel, there is no pressure. Also important is the hose size on your reel. The pressure loss on hose smaller than 5/8" is tremendous when you are talking about lengths over 50'. My rig has the standard D30 coupled to a 6.5HP engine. Pressure at the end of 200' of 3/8" hose is not 550PSI, but I can go up a 25' tree.

fireman1173005
01-17-2009, 03:53 PM
The supply to your hose reel does not generally need to be as large as the supply to your pump. Do you have a line on the discharge side of your pump set up as "bypass"? That is to say any excess(unused by the hose reel) goes back to the tank hopefully in the form of agitation.

I do have a bypass line. Do you think that if I made my line going to my reel it would increase my pressure?

fireman1173005
01-17-2009, 03:57 PM
What kind of pump? If this is a water transfer pump, those are not made to generate any kind of pressure. The centrifugal pumps I have seen designated for spraying are good for at least 75 PSI and over 20 GPM. At that rate, you should be able to run a boom or Lesco gun. Check your bypass or agitation valve too. If that is set to dump it all before it goes into your reel, there is no pressure. Also important is the hose size on your reel. The pressure loss on hose smaller than 5/8" is tremendous when you are talking about lengths over 50'. My rig has the standard D30 coupled to a 6.5HP engine. Pressure at the end of 200' of 3/8" hose is not 550PSI, but I can go up a 25' tree.

Yes it is a transfer pump. I didn't realize that they were less pressure that those for spraying. It was given to me so I can't complain. I can get it to put out about 40 psi, but that is wide open. Would I be better off switching to a roller pump at this point? I can use the same engine and buy a roller pump for about $100.

Brian

greendoctor
01-17-2009, 04:05 PM
Yes, a roller pump would be more suited for your purposes. I cannot use roller pumps because what I run through my rig would eat the rollers in no time. You are ok if all you are going to spray is weed control and clear solution fertilizers. I spray too many fungicides and other chemicals that form a gritty suspension.

fireman1173005
01-17-2009, 04:48 PM
Yes, a roller pump would be more suited for your purposes. I cannot use roller pumps because what I run through my rig would eat the rollers in no time. You are ok if all you are going to spray is weed control and clear solution fertilizers. I spray too many fungicides and other chemicals that form a gritty suspension.

Would a 3.5hp motor work ok for a roller pump? Most skids that I see for sale have 5 to 5 1/2 hp motors on them.

greendoctor
01-17-2009, 05:07 PM
Sure. Roller pumps have low power requirements.http://www.rittenhouse.ca/content/attach_files/Roller_Pumps_Hypro.pdf A pump for a lawn spray rig would be sufficiently powered by a 3.5HP engine. I doubt you need the pump that passes 50 GPM.

fireman1173005
01-17-2009, 05:17 PM
thanks for all your help, and the link!!!

RAlmaroad
01-17-2009, 05:19 PM
If you do change to a roller pump, make sure that you have an appropriate reduction (6:1 commonly) from the engine to the roller pump. I use the ones that are powered by the tractor PTO. Too high of a RPM will destroy the rollers quickly. Check that by-pass that it is not too far open as Greendoctor mentioned first.

fireman1173005
01-17-2009, 05:39 PM
If you do change to a roller pump, make sure that you have an appropriate reduction (6:1 commonly) from the engine to the roller pump. I use the ones that are powered by the tractor PTO. Too high of a RPM will destroy the rollers quickly. Check that by-pass that it is not too far open as Greendoctor mentioned first.

I checked the bypass, not the problem. I am going to be running it off of an 3.5hp motor, do I still need a gear reducer?

greendoctor
01-17-2009, 05:46 PM
Yes you do, if the engine does not have one already. At this point, you might as well go big and get at least a Hypro D252. That has a gear reducer and it has enough pressure to do most applications. A roller pump is limited in how much pressure it can put out. When spraying for insects in turf, I like up to 500 PSI at the boom.

RigglePLC
01-17-2009, 06:06 PM
Fireman, are you absolutely sure the pump is fully primed and filled with water? Are you using a filter in front of the pump? Is screen plugged? Filter gasket tight? Suction leak? If you take the filter off and let the water flow out by gravity, measure the flow--can you get a gallon in 10 seconds? That would be adequate. Do you use a pressure relief valve to direct some flow back into tank--or just a partially open throttling valve? You also need a "dump valve" that releases all pressure back into tank--use it for agitation-- close it while spraying. Take the hose off from your bypass--squirt into a bucket--and find out how many gallons per minute are coming out the bypass. How many gallons per minute are coming out of your reel hose? How many at the gun?
Get a 5 horse motor--in case you graduate to a D-30 pump in the future.

SpreadNSpray
01-17-2009, 06:37 PM
Fireman, are you absolutely sure the pump is fully primed and filled with water? Are you using a filter in front of the pump? Is screen plugged? Filter gasket tight? Suction leak? If you take the filter off and let the water flow out by gravity, measure the flow--can you get a gallon in 10 seconds? That would be adequate. Do you use a pressure relief valve to direct some flow back into tank--or just a partially open throttling valve? You also need a "dump valve" that releases all pressure back into tank--use it for agitation-- close it while spraying. Take the hose off from your bypass--squirt into a bucket--and find out how many gallons per minute are coming out the bypass. How many gallons per minute are coming out of your reel hose? How many at the gun?
Get a 5 horse motor--in case you graduate to a D-30 pump in the future.

You guys have all gave some GREAT info!
Double check what Riggle said, especially the suction leak. I bought a brand new tank with a small crack in the filter housing. It never leaked any liquid, not a drop. It had low pressure at the gun. It took a while to find the problem. When I took the cap off the filter to check for flow, I still did not see the crack. Only when I tightened the cap back up, the crack became visible. So check your hose clamps too.

fireman1173005
01-17-2009, 06:58 PM
Fireman, are you absolutely sure the pump is fully primed and filled with water? Are you using a filter in front of the pump? Is screen plugged? Filter gasket tight? Suction leak? If you take the filter off and let the water flow out by gravity, measure the flow--can you get a gallon in 10 seconds? That would be adequate. Do you use a pressure relief valve to direct some flow back into tank--or just a partially open throttling valve? You also need a "dump valve" that releases all pressure back into tank--use it for agitation-- close it while spraying. Take the hose off from your bypass--squirt into a bucket--and find out how many gallons per minute are coming out the bypass. How many gallons per minute are coming out of your reel hose? How many at the gun?
Get a 5 horse motor--in case you graduate to a D-30 pump in the future.

I'm getting a gallon of water per 8-9 seconds from my tank.

tlg
01-17-2009, 07:09 PM
OK I am trying to plumb a skid sprayer and am having trouble getting enough pressure. I have 1" supply line running from my tank to my pump and 1" line from my pump to my reel. I have a centrifugal pump so of course it isn't going to put out as much pressure as a roller pump. I am wondering if I should increase the size of my supple line coming into the pump to say 1 1/2" so I will make sure and bring in more water to my pump than hopefully I am putting out, I think I may be starving my pump. What do u guys think?Thanks,

Brian:confused:

I going to assume that the pressure problem is a the gun. If that's the case I would try the following. One increase the supply line to about 1 1/2 to 2". Have a return line for an agitator 1 1/2" in dia. Make sure the jet or jets on your agitation line is not to big. You only need enough to get the tank rolling to keep things in suspension. You want as much pressure going to the reel as you can get so I would think a 5/8 line would be a good start. I don't know what you expect for gallons out your gun but you probably won't get more than 1 to 2 gallons a minute out of it between 30 and 40 psi. What are you going to use the rig for? Lawn spraying??? Or ?????

Grassmechanic
01-19-2009, 10:24 AM
His pressure problem is clearly with the pump. Centrifigals are not designed for this type of application. He was given good advice on the roller pump with a gear reduction. Another good choice is either a piston or diaphragm pump.

fireman1173005
01-19-2009, 11:01 AM
I looked at a Hypro pump and the directions said that it could be coupled right to the motor, it didn't show any kind of gear reduction, does this sound right?

tlg
01-19-2009, 11:07 AM
His pressure problem is clearly with the pump. Centrifigals are not designed for this type of application. He was given good advice on the roller pump with a gear reduction. Another good choice is either a piston or diaphragm pump.

They may not be designed for it, but they can be made to work. About a dozen years ago I worked for a large company (8500 customers) in SE Michigan. Every spray rig we had was a centrifugal pump. In fact they were trash pumps. We custom built all our spray rigs and had about 15 trucks with centrifugals. They worked great and were simple to operate. They were also pretty much maintenance free as a typical set up would run for years without any breakdowns. We even had two boom sprayer trucks with the same type of pumps. The pump only needs to create pressure, agitate the tank and have sufficient volume. Piston , roller and diaphragm pumps are all great and of course and will work as well. There's always another way to do something. If it works how can it be bad?

fireman1173005
01-19-2009, 11:12 AM
They may not be designed for it, but they can be made to work. About a dozen years ago I worked for a large company (8500 customers) in SE Michigan. Every spray rig we had was a centrifugal pump. In fact they were trash pumps. We custom built all our spray rigs and had about 15 trucks with centrifugals. They worked great and were simple to operate. They were also pretty much maintenance free as a typical set up would run for years without any breakdowns. We even had two boom sprayer trucks with the same type of pumps. The pump only needs to create pressure, agitate the tank and have sufficient volume. Piston , roller and diaphragm pumps are all great and of course and will work as well. There's always another way to do something. If it works how can it be bad?

Ok, here is a question then. My sprayer only shoots maybe 6-8ft. on a straight stream and when on a cone pattern doesn't seem like it puts out enough liquid, I'm afraid it would take to long to spray a yard. Using my spray gun how long should it take to fill up a gallon can or something to make sure I'm putting out enough volume?

Brian

RAlmaroad
01-19-2009, 11:17 AM
I looked at a Hypro pump and the directions said that it could be coupled right to the motor, it didn't show any kind of gear reduction, does this sound right?

Most rollers are designed to work at a specific RPM. The chart is the above thread shows some at different speeds. The problem I see is that the Honda engine, even a fixed rpm one, will fluctuate way off the recommended rpm. Call Rittenhouse and discuss it with those guys. I've found them worth the little extra cost of their products. Let us know what you find out. Another thought...you'll end up with a $200+ for a good roller and you can invest in a Hypro 252 with a regulator and coupler for a little under $500 from Rittenhouse. Great pressure but a little shy on the GPM.

tlg
01-19-2009, 11:22 AM
How many gallons per 1000 are you going to apply?? The spray rigs we use to use were designed to spray at 1 gal per 1000 sq ft. at about 35 psi. We tried to get about 1 3/4 gallons a minute out of the gun. We were running 5/8 spray hose to have adequate volume and no more than 300 ft of hose.
Are you using a chemlawn type gun?

RigglePLC
01-19-2009, 01:54 PM
Are you melting urea and using liquid fert mixture? If so, you need minimum of about 3 gallons per minute output at the gun. (Chemlawn gun.) What is your output in gallons per minute at the gun with out a nozzle? It does not need to spray 6 feet straight out. Hypro D-252 pump (like mine) is adequate. Most have 6 to 1 gear reduction built-in, (for use with gasoline engine).
If you are doing mainly weed control, one gal per minute will be adequate. Use a smaller droplet nozzle, with a spray wand. You don't need much pressure--let the chemical do the work. More pressure just means more drift. :waving:

RAlmaroad
01-19-2009, 02:31 PM
The south and coastal areas generally are more fungus prone than northern states I would guess. A main reason I switch to the 252 was to use more pressure for my fungicides. When using something like Ensignia I only had about 25lb last year. This year I'm hoping that the 60 or more pressure will force the chems into the soil where it needs to be. I generally try to get out very early when it is still to avoid as much drift as possible. So far so good. We'll see come June-September.

tlg
01-19-2009, 02:34 PM
We were spraying urea at just under 2 gal per minute out the gun. I realize most people would say that's crazy but we did it. You had to walk at a good pace ( not like the chemlawn guys spraying 4 gals a minute ). yes there was some tip burn but nothing to worry about. The biggest problem we had with this set up was on windy days. At this low volume patterns broke up and drift could be an issue.