Tyler Ro-Tap RX-29, Руководство по эксплуатации

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TEST SIEVE ANALYSIS
Test Equipment
Test sieves “nest” together to form a “stack” of sieves. In most sieving tests the 8 inch diameter sieve is used.
A test sieve shaker that provides both circular and tapping energy is recommended. Uniform mechanical
motion will provide the most consistent results.
Testing Times
Free flowing, coarse material requires less time than fine, bulky particles. Once you establish the proper time,
duplication of testing becomes extremely important to obtain accurate, repeatable results.
Conduct repeated experimental testing to determine the optimal testing time. For example, perform tests of 5,
10, 15 & 20 minutes. You can determine the optimal time when the results between the different times change
no more than .5 to 1 percent. The shortest time should then be used consistently.
Performing a Sieve Analysis
You can begin your particle size distribution analysis after you properly collect, prepare and size a sample.
Select test sieves with mesh openings that reveal particle distribution at critical sizes. These are usually stated
in a product specification or determined by material processing requirements.
To perform the analysis, do the following:
1.
Stack the sieves on top of each other with the coarsest (largest) opening on the top of the stack.
2.
Put a bottom pan under the finest (smallest) opening sieve. This pan collects “fine” material that passes
through the last one.
3.
Use a laboratory scale (accurate to .1 gram) to weigh an empty container (such as an extra empty
bottom pan) and establish the tare weight.
4.
Weigh the sample material.
5.
Empty the sample into the top of the stack. Make sure you do not overload the surface as this causes
“blinding” or blocking of the openings.
6.
Put the stack into the sieve shaker.
7.
Place a cover on the top of the stack.
8.
Make sure the stack is securely in place.
9.
Set the proper length of time to agitate the material.
10.
Turn on the shaker and run the test.
11.
After the shaker stops, empty the material from the coarsest sieve into the empty container that you
weighed in step (3). Use a soft bristle brush to gently brush the underside of the sieve to remove all of
the particles.
12.
Tap the side of the frame with the handle of the brush to clean the remaining material from the sieve.
13.
Weigh the contents in the pan to the nearest 1/10 gram and record the data.
14.
Return the material to its original sample container.
15.
Repeat steps 11 through 14, using the container referenced in step (3) for each sieve, including the fine
material in the bottom pan.
16.
Total the weights to make sure the sum of the retained material and the material in the bottom pan is
as close as possible to the original weight. Check your specification for allowable variation.
17.
Divide the weight obtained from each sieve by the weight of the original sample. Record the percentage
for each sieve.
18.
Calculate and record the cumulative percentages as required.