Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Dry in Wyoming, need waterline help to water cattle 5

Status
Not open for further replies.

carter livestock

Agricultural
Jul 26, 2022
9
Hey all, I am rancher in Wyoming. We raise and market some of the most nutrient dense grass finished beef in the US, Carter Country Meats. We operate a regenerative grazing strategy to build our soils. We have been extremely dry this year and our natural springs and water sources will not be able sustain our herd with existing infrastructure. I am asking for help designing the following water system

My Plan is to pump water from a large reservoir to different locations on the pasture. Once the area is grazed we would like the flexibility of moving our water tank and line to a fresh area. I am looking for help in sizing a pump and designing the system.
Max distance to pump: 2miles
Elevation difference: 400ft higher than pump
Volume: 50gpm
Pipe Diameter. 1 1/2" poly pipe
Fuel source: gas/diesel
pipe fittings: butt fuse

Ideally, i would like to have an inline pressure switch that would trigger the pump to turn on when the water drops below targeted pressure, which would be initiated when cows begin to water. We use float valves on water tanks to conserve water. Vice versa, when the cows stop drinking and the tank is full, the float valve closes, building pressure and shutting the pump off. I don't know if this is possible and would appreciate your help


 
Replies continue below

Recommended for you

pump_1_tvdvo2.png
 
I have this old pump collecting dust, and if i can get my generator running this system has legs. With the above info, in mind, I feel it would be beneficial to add a storage bladder to reduce my gpm demand. With this system would i be able to push the original 2 miles in 1.5 or would the pressure be too high for HDPE. Or would it be more realistic to just push the 1 mile?
 
Which pump power?

How big is the storage bladder?



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
The pump looks about right for your original 1 mile 50gpm requirement to 300ft. The 10Hp rated pump gives a 550ft head at 50gpm and you only need 500 ft to reach the 300ft elevation. You will get slightly more flow.

A 2 mile long 2" diameter at 48gpm needs 171 psig for flow loss which is 400ft head.
Add elevation of 200 ft brings that to 600 ft total feet head, or 700ft total head to pump up to a 300ft elevation.

Considering the pump only
If its the 10Hp pump, you can pump 42.5 gpm at 600ft head, so you can lift at least 42.5 gpm to 200ft elevation. Pumping up 300ft elevation (700ft total head) will get you at least 30gpm flow.

Looking at the 2" pipeline table, 32gpm only has 1/2 the flow loss of a 48gpm flow, so a 2"pipeline would only lose 200ft at a 32gpm rate. Flow would go up to around 36gpm to a 300ft elevation. Or you would be at around 44 gpm going to a 200ft elevation. (A bit of guess work there, as I have not run the numbers out).

I think, if I remember right, it's still in the HIGH range of HDPE, but 2 miles with a 300ft lift is getting on to 300psig, so it will be very close to HDPE limits.

Your pump will probably work out to some acceptable compromise, its the pipe pressure that could be the problem. See what the max pipe pressure allowable is that you can buy.

How will adding a bladder lower your flow rate requirements? Id think that pumping to a stock tank at a lower flow rate for a longer time than the livestock is drinking would be the way to supply the demand using a reduced flow rate.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
 
How much of this pipe do you have? You can run pipes in parallel to reduce losses, even if it's only a partial distance.
 
I plotted the total pressure drop "System Curves" for 1, 1.5 and 2 mile long pipelines, each with a 300 ft pumping lift.

I plotted the 10 Hp pump curve on top of those system curves.

The pipe/pump system will operate at the intersection of the pump curve (yellow) with the respective pipeline's length curve. Pump discharge pressure for the 2mile pipeline will be 258 psig at a flow rate of 42 gpm. The 1 mile long pipeline pump discharge pressure is 228 psig at a 52 gpm flow rate.

2in_pipe_10_Hp_pump_l25usz.png

Disregard the legend's top line.

If you can't find pipe with a 344 psig allowable pressure, you should add a relief valve at the pump discharge and set it to the allowable pressure of the pipe that you do install.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
 
1503-44 You sir are a beast. My family and cattle are grateful for your kind help. Thank You!
 
You're welcome. Glad to help.

I was looking more closely at the GE Cross section you posted and that shows an elevation change of 370ft, not the 300ft. If you do want to pump to 370 ft, the curves will change, but its easy to make new curves. Just raise them by the difference in the new elevation and 300ft. If you do need to pump to 370ft, then slide all 3 pipeline curves upward by 370-300 = 70ft higher. Leave the pump curve where it is. Notice that the 2 mile long pipeline would then intersect the pump curve at around 35 gpm at a total head of around 650ft. The pump discharge pressure would also rise from that new total head by 650ft x 0.43 = 280 psig.

If elevation drops, just lower the pipe curves. If you pump to a 200ft elevation, lower all pipe curves by 100 ft. The 2 mile pipeline would flow at 55gpm, the 1 mile pipeline at around 62 gpm.

Good luck. We're here anytime you need more advice.





Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
 
I cleaned up my spreadsheet and I am attaching it here.
Now you can do modifications to pipe diameters.
All you need are pipe pressure loss data (from the web link) for other diameters.
You can change the lift elevation.
You can change the length of the pipelines.
You can change the pump by entering different pump flow vs head data.

It will plot the picture above, label the curves properly, plus show resulting operating pressures on the right hand axis.

Have fun

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
 
 https://files.engineering.com/getfile.aspx?folder=a97b3f48-2716-4f00-8644-06568b776f06&file=Draw_System_&_Pump_Curve_.xlsx
Carter livestock,

Mr 44 is indeed very helpful, but I need to sound a note of caution here as you're not providing us with enough information to help you and depending on the answers it may not work at all.

"I have this old pump collecting dust, and if i can get my generator running this system has legs"
You need to tell us which actual pump you have. If its the 10 hp then it's ok, but the others are too small ( not enough pressure / head) and the 15 hp is too big ( too much pressure / head. The information will be on the nameplate of the pump or motor.

"With the above info, in mind, I feel it would be beneficial to add a storage bladder to reduce my gpm demand"
Nobody understand what this is or how big a volume it is. Please tell us.

With this system would i be able to push the original 2 miles in 1.5 or would the pressure be too high for HDPE.
"Poly Pipe" is very vague. A bit like saying you have a "tractor". Many different sizes and power.
HDPE is a start, but the pressure rating is not high for may and you need to tell us the SDR of the pipe - it will be stamped on the pipe. In the table Mr44 has supplied, in practice you normally don't find anything thicker than SDR 11 which has a max head of 200 ft or so. But SDR 17 and 21 is also very popular and has a lower rating.

Also will this pipe be buried? If laid on the surface and it heats up it could fail as it really doesn't like temperatures much above 35-40C.

SO a bit more information will help you avoid disappointment

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
Also of note - I didn't see this mentioned - HDPE is degraded by UV light. It's stabilized often with carbon, but degradation still occurs, albeit at a slower rate.

Based what I've seen, you'll be pushing the P/T limits of the pipe. The temperature limit may be transient, but it WILL occur when you are in the summer time with no water demand. Add in the pipe becoming more brittle over time due to UV exposure AND continual pipe deflections from night/day temperature swings, this 1-2 mile pipe may not last very long.

1503-44 and LI have given you a lot in terms of the requirements (pump/system curves, P/T ratings), but I think you should give some thought to the material selection for the pipe. My gut feel is that HDPE is the wrong choice, but maybe others think otherwise?
 
I'm just trying to help him find a practical solution, within his constraints, that doesn't require access to Exxon's bank account.

There are few alternatives to slick plastic something here, if any. Steel pipe could easily double his flow losses. 2.5"D 60gpm= 3.2 psi/100ft. Game over; get a tank truck. What pipe would you suggest?

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
 
1503-44,

I agree with you. I don't have any better solutions in mind - CPVC piping suffers from the same issues, and I don't think it has the rating required. Steel pipe would also a increase costs quite a bit, I think, and also suffer from localized corrosion. HDPE might very well be the best option for the available budget.

I do think some consideration should be given to coverage of the pipe and/or suggestions for how the pipe should be laid to compensate for thermal growth - the expansion coefficient for HDPE is quite large.

Are there any cheap options for UV protection? Perhaps opaque tarps wrapped around the pipe?

Any suggestions or guidelines for how the pipe may be placed to avoid excessive stress from thermal expansion? I'm not a pipe guy, but I would anticipate issues if it is a single straight 1-2 mile run of pipe. Maybe the terrain will provide enough bends. Any practical suggestions for the OP that doesn't involve topographical maps and pipe stress analysis?

 
Not sure, but I think it could be painted with UV resistant paint. It also won't disintegrate overnight, but there isn't much said about lifetimes under UV. Some sources say 10yrs, others mention 50 yrs. Not sure about what criteria constitutes end of life. 50% of initial allowable operating pressure? 25% Leaks? They don't say.

Yes it is 10x more expansive than steel, however there is no thermal stress if it not restrained, but it could move about some and abrade if laid on rough or sharp rock. Sharp rock should be removed. Laying it with preconfigured snaking curves between anchor stakes can limit excessive movement.

More worrisome for me than either of UV and expansion is its temperature sensitivity. Rating can drop to half from 70 to 100°F. Burying it would help keep it cool. It might also help to run at a very small flow rate until the pipe is cooled enough to run at higher pressures. Or running it at intervals to keep the pipe cooled during hot weather: a cooling cycle. Burying it at a 2 to 3ft depth would likely maintain it at a monthly average temperature.

Like I say, there's not many pipeline alternatives. It's the HDPE way, or the highway. Reinforced, multilayer, double wraped, high pressure plastic stuff costs more than steel. Steel flow friction factors are way too high anyway, needing a larger diameter, if not a 2x power pump as well.




Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
 

What is the cost of this system?
What would be the cost of hiring a professional to design it?
Would the cost of having it designed for the particular situation be less than the cost of a few cattle dying if a design gleaned from 30+ posts on a free internet forum fails?
 
Our water tanks hold enough for 10 cows to drink at a time, it tanks them 2 min to drink on average 10gal each, hence 50 g/min flow. As long as the flow keeps up the cattle will be patient and wait their turn, not tearing up tank. in the past weve had much larger tank to drink from. If i water 50 head at time, they require the a system that can carry much more volume.
 
For an emergency case do you not think you can water the cows at a slower rate and let them take turns?

If you have a tank can you not fill it over hours and then use it to deliver the 50gpm when the cows are present?
 
How much does a cow drink during a 24hr WY summer day?

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
 
Carter livestock.

I appreciate you're probably running around herding cows, but if you want this water system to work then you need to stop for a minute and do some thinking.

You may indeed have a 50 gal/min flow, but for 50 cows that only lasts for 10 minutes - 500 gallons. Then what? How long until they need to drink again?

Thus you may only need a small fraction of the max drinking water flow so long as your tank is big enough and can re-fill in between the cows drinking it, then your pump flow may only need to be 10 gal/minute or so and your pipe might be big enough.

You biggest issue you face by far is the elevation climb. This needs quite a lot of pump power and pressure at the pump end simply to push water up hill leaving not very much for frictional flow losses.

As we have said "poly pipe" is a vague term and may actually burst on you if you try to make it go too much uphill or install too big a pump.

If you can read back and answer some the questions we have asked, we can probably advise you much better.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor