how to calculate the weight and power of drum mixer?

My rotating drum mixer has a diameter of 2m and a length of 5m, made from stainless steel im producing 45t/ph of detergent powder. a residency time of 3 mins. my density of the mixed product 450g/l. How do i calculate the weight of the drum. how do i calculate the power required. 2250kg are passed through every 3 minutes.

2013-05-27T20:47:35Z

my volume is 15m3

2013-05-28T23:56:03Z

I need to know how to calculate the weight of my drum without the powder inside it based on the above dimensions, would it simply be w=volume x density = 15*450=6750kg?

2013-05-29T00:01:37Z

speed of drum is 15rpm

Dr. Watkin,. I presume2013-05-28T21:26:22Z

Favorite Answer

Based on the dimensions the drum volume is actually 5pi m^3 = 15.7 m^3

But I think that is irrelevant because the batch size is 2250 kg. This gives the maximum mass of the drum's contents.
At a density of 0.45kg/litre, the batch volume is 2250 / 0.45 = 5000 lites = 5.0 m^3
So the drum is only about 1/3 full at any time.

45t/hr = 45000kg/hr = 45000/60kg/min 750kg/min = 2250kg/3 mins
which also checks out.
So there are 45000/2250 = 60/3 = 20 batches per hour.

Weight of drum contents is m*g = 2250*9.81 = 22100 N (3 s.f.)

Assuming the drum rotates around a horizontal axis, it must lift the entire 2250kg of powder a distance of at least 1m (the drum radius), at least once every 3 minutes = 180s

So the minimum power required is m*g*h / 180
= 2250*9.81*1 J / 180s = 123 W

But if the drum rotates at, say, 6 rpm (more realistic):
6rpm = 10s per rev
So Power is then 2210 W

Hope this helps, but the question is unclear.