Today is a good day for me because I finished the first lunch of the new application about bucket calculation. Its name is " Bucket CalPro "
For the bucket elevator design process, the designer should have knowledge about the bulk materials and standards for design.
This tool is used DIN 15234 - Bucket for Elevator.
Basic calculation.
1.Volume Capacity (Qv) = 3.6 * v * φ * (VB / α )
Where :
Qv = Volume capacity ( m³/h)
v = Speed (m/s)
φ = Degree of filling.
α = Bucket pitch (m)
VB = Norminal capacity (liters)
2. Mass capacity (Qm) = Qv * δ
Where:
δ = Bulk density (t/m³)
Qm = Mass capacity (tph)
3. Pulley revolution (n) = (v*60)/(¶*D)
Where:
n = Pulley revolution (rpm)
D = Pulley diameter (m)
4. Peripheral force (Fu) = Fh + Fb + Fn
Where:
Fu = Peripheral force (N)
Fh = Main resistance (N)
Fb = Loading resistance (N)
Fn = Secondary resistance (N)
5. Main resistance (Fh) = (Qm * g * H )/ 3.6 * v
Where :
g = Gravity acceleration (m/s²)
H = Height of elevation (m)
6. Loading resistance (Fb) = ( Qm * g * Ho )/ 3.6 * v
Where :
Ho = Additional height (m) ; = 4 * v + 4
7. Secondary resistance (Fn) = (cn - 1)*(Fh+Fb) ; cn ≈ 1.1
8. Drive power at the head pulley (Pt) = (Fu * v)/1000
9. Motor power (Pm) = Pt / ⁿ
Where ;
ⁿ = Degree of efficiency ( 0.5 - 0.95 )
Pm = Motor power (kW)
10.Nominal belt strength (kn) = (T1 * S)/B
Where :
kn = Norminal belt strength (N/mm)
T1 = Belt tension (N)
S = Factor of safety
B = Belt width (mm)
11.Belt type assessment; The belt stress T1 can be approximately estimated.
T1 = Fu + Fst + Tv + Tt
Fst = 9.81*H*(m'b+m'g)
Tv = c2 * ka *Fu - Fst - Tt
Tt = Gt * g/2
Where:
Fst = Slope resistance (N)
Tv = Pre tension (N)
Tt = Weight of take up pulley (N)
m'b = Weight of bucket and fastening (kg/m)
m'g = Belt weight (kg/m) ; 11.5 * B
ka = Start up factor ; = k * ( Pn/Pm)
Pn = Installed power (kW)
k = 1.2 to 1.6 ( depending on coupling )
c2 = Drive factor
Gt = Weight of take up pulley (kg)
Note : If Tv ≤ 0 Then an additional pretension is not necessary.
