# Cow manure push force

1. Jun 24, 2014

### jmex

hello folks,

If i want to drag(push force) cow manure of suppose 500kg and i took help from google to find out its coefficient of friction which is found is 0.4 to 0.8. So according to F=μN if i am right taking 0.8 coefficient of friction, my push force is 500*0.8?

Is there any other parameter i have to consider?

Guide me if anywhere i am wrong.

Thanks

2. Jun 24, 2014

### Baluncore

Your question is somewhat unusual, but theoretically OK.
Except that a friction coefficient is usually quoted between two different solids.

If the manure is wet it will be quite heavy and will tend to flow. Friction is probably inapplicable.

If it is dry, it will be light weight. The friction coefficient will be similar to wood or paper. It will tend to break up when pushed.

Laying newspaper, sprinkling sawdust, or dry dung between steel plates will often prevent them sliding on each other.

3. Jun 24, 2014

### jmex

Thanks for your help. I never gave a thought of dry or wet concept.

Again if I'm to clean it up what should be my minimum distance between pusher lower part to rcc path. I'm just assuming 1cm but is there any way to figure that out? If I do push by dragging from bottom most part it'll touch rcc and there will be bigger COF which will lead to high push force required. so can suggest how to sweep out the manure.

4. Jun 24, 2014

### dlgoff

5. Jun 24, 2014

### 256bits

Is your manure in a slury or a semi-solid/solid form? Beef and dairy cow excretment are somewhat different from each other and this deprends upon the diet. Bedding material such as sand, wood chippings, or straw can be added to make the manure less fluid.

http://osufacts.okstate.edu/docushare/dsweb/Get/Document-7612/BAE-1751.pdf
Figure 3 of this document shows which equipment is normally used to handle manure based upon moisture content.

Although not necessarily totally complete, this document gives some more information.
Static friction values on several surfaces from table 1 seems to be higher than what you quoted. See figures 7,8,9 and 10 for graphs of values using a regression technique from the data points.

Table 13 gives the shear stress failure as a function of normal stress, which would be the values to use if you are not scrapping or pushing on the surface, but above.

The heading 1, Review of Literature gives an indication that manure has variable properties, and can exhibit non-Newtonian pseudoplastic behavior.

Last edited by a moderator: May 6, 2017
6. Jun 24, 2014

### Baluncore

What surface are you trying to clear?
What will you do with the product that can't be pushed uphill?

The optimum method will depend on the availability of water or straw. Consider washing it out to a separation system, then recycling the washdown water. You could spread something like straw or sawdust first. Then move it all to a fermentation tank to produce methane for power generation, or spread it on pasture or barren ground to improve soil conditions. Consider using dung rolling beetles to bury dung in the soil. http://en.wikipedia.org/wiki/Dung_beetle

7. Jun 25, 2014

### jmex

thanks it's worth reading. but I am confused related to TS(total solid concentration). can you explain what it is?
@256bits

8. Jun 25, 2014

### Chronos

Bull manure is easier to push than cow manure.

9. Jun 26, 2014

### 256bits

Organic matter contains percentages of water, volatiles, and solid matter.
Remove the water and volatiles and what is left is the solid material.

Depending on the ratio of water to solid, since that is the major ratio in consideration, manure can be handled by a pump as a slurry, or by mechanical earth moving equipment, or by manual labour.

If the semi-solid manure has the correct consistancy, it can also be manipulated manually by a shovel or pitchfork. With a shovel, it either has to be more fluid or more solid so that the manure does not stick to the shovel. With a pitchfork, another consistancy is desired so that the manure does not fall through the tangs - in this case not too fluid and not too solid ( one can pick up a dried cow patty that has dried out and has kept its shape intact, but not if it has disintegrated)

500 kg of cow pie stuff is about 2 cubic meters volume. If that is all you have then you can load it onto a sled, a wheel barrow, or utility trailer box and transfer to another location, depending upon how far. Time frame you would be looking at something like several hours for the process and a good workout. If that is the amount of accumulation per day, then you would probably look at other labour saving methods.

10. Jun 26, 2014

### 256bits

Hardy har har :rofl: