Screw conveyor selection calculation

(1) Spiral diameter calculation spiral diameter of screw conveyor:

Where D———helix diameter, m;
K———Material characteristic coefficient;
Q———Transportability, t/h;
ψ———filling factor;
γ———loose density of material, t/m ³ ;
C———The angle of inclination.
The D value calculated according to formula (1) shall be taken as the standard spiral diameter: 150, 200, 250, 300, 400, 500, 600 mm.
If the particle size of the conveyed material is large, the spiral diameter D should also maintain the following relationship with the particle size of the transported material:
For unclassified materials: D ≥ (8 ~ 10) ^d (2)
For graded materials: D ≥ (4 ~ 6) ^d _max (3)
Where d———the average particle size of the material, mm;
d _max ———the maximum particle size of the material, mm.
If a larger spiral diameter is selected according to the particle size of the transported material, the lower spiral speed can be selected to maintain the service life under the condition that the transport volume is constant.
(2) Calculation of spiral speed
The spiral rotation speed should not be too high under the condition of satisfying the conveying capacity, so as to prevent the material from being thrown up by the excessive tangential force, so that it cannot be conveyed forward. Therefore, the spiral speed n cannot exceed its limit speed n _j :

Where n———spiral speed, r/min;
n _j ———spiral limit speed, r/min;
A———The comprehensive characteristic coefficient of the material.
The n _j calculated according to the formula (4) should be rounded up (n) to the following rotational speeds: 20, 30, 35, 45, 60, 75, 90, 120, 150, 190 rpm. [next]
After taking the value of the spiral diameter D and the speed n, the filling factor must also be checked:

Where t———spiral pitch, s method is 0.8 times the diameter of the spiral, D method is the same as the diameter of the spiral, m; other symbols are the same as before.
(3) Power calculation screw shaft power:

Where N ₀ ———axis power, Kw;
H———the height of lifting or lowering when tilting, positive at the time of shipment, negative at the time of shipment, m;
L———the horizontal projection is long, m;
Ω ₀ ———The drag coefficient of the material.
Motor Power:

Where N———motor power, Kw;
K ₁ ———the reserve factor, generally taking K=1.15;
η———The total efficiency of the drive unit is generally η=0.9～0.94.
(4) LS type screw conveyor
(1) LS type fixed screw conveyor is a stereotyped product. The spiral diameter has 12 kinds of 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1000, and 1250 mm.
(2) LS screw conveyors are divided into two types: A-type method and B-type method according to different occasions;
(3) The assembly method of the driving device of the LS screw conveyor is divided into two types: left and right;
(4) The discharge port of the screw conveyor has three types: square, hand push and rack type. The opening and closing directions of the rear two kinds of discharge ports are left and right.