Determine the angle of repose and influence of lubricant on angle of repose.

 Experiment

Object:

To determine the angle of repose and influence of lubricant on angle of repose.

Requirements:

Funnel, funnel stand, powered sample, butter paper , measuring scale etc.

Theory:

Flow property of powder is generally assessed by determining the angle of repose of the powder.

Defination of angle of repose:

It is defined as the maximum angle possible between the surface of the pile of the powder and the horizontal plane.

The angle of repose can be calculated using the formula:

tanθ = h/r

Where, θ= angle of repoter

h= height of the heap of powder

r = radius of the base of the heap of the powder.

Generally the powder with angle of repose more than 50° have unsatisfactory flow properties while those with minimum angle close to 25° corresponds to very good flow property.

Procedure:

1. At first assembly of funnel with tripode stand was prepared.
2. Then 10 gm of powder sample was weighted and then poured it into the assembly and angle of repose was calculated.
3. Then similarly the 10 gm of sample with mixing different  concentration of lubricant ie 100,200,300,400 mg was prepared.
4. After that this sample+lubricant was poured one by one and the and height and radius of each concentration was noted down.
5. At last the angle of repose of each concentration was calculated.

Observation:

Draw observation table of sample without lubricant and sample with lubricant and

Also Draw graph between angle of repose(y axis) and amount of lubricant (x axis).

Result:

The angle of repose of sample without lubricant was found to be_____ and the sample with different lubricant concentration was found to be____

Reference:

• Agrawal SP, Khanna R. "Physical Pharmacy" CBS Publisher and Distributor Pvt. Ltd New Delhi 2nd edition Reprint 2009 pp 44-45
• Gaud RS,Gupta GD. "Practical Physical Pharmacy" CBS Publisher and Distributor Pvt. Ltd New Delhi 1st edition Reprint 2016 pp 224