centrifugal feeder design
Post on 18-Nov-2015
68 Views
Preview:
DESCRIPTION
TRANSCRIPT
-
www.packexone.com 1
Centrifugal Feeder Design
A centrifugal feeder, or rotary feeder, has a conical central driven rotor
surrounded by a circular bowl wall. The feeder separates parts utilizing
centrifugal force and the parts revolve with high speed and are pulled to the
outside of the bowl.
The design shown in this tutorial is a more sophisticated concept where an
inclined revolving disc brings the parts to the rim of a revolving bowl. This
concept allows for a series of qualifiers to gently orient the parts for transfer to a
downstream process.
Tutorial
Phase 1: General geometry
Phase 2: Drive design
Phase 3: Structure / Tooling
Warning This tutorial is to
serve as a guide covering most
design areas. User is to
consult and respect local
government regulations where
the unit is to operate.
-
www.packexone.com 2
Phase 1 General geometry (1)
Operation:
Parts are metered from a prefeeder on the rotating disc.
The disc carries the parts to the rim of the rotating bowl in a single lane.
Fixed mechanical or pneumatic qualifiers orient and qualify the parts.
Improperly oriented parts are ejected from the rim to the disc for recirculation.Properly oriented parts moved out of the rim and out of the feeder.
Feed rate is affected mainly by:
The part size, its natural orientation and the desired orientation.
The disc and bowl speeds.
Part speed shall not exceed 100 meters/min to prevent damages.
DISC
BOWL
BOWL RIM
-
www.packexone.com 3
Phase 1 General geometry (2)
Calculated rate:
The feed rate, R, can be approximated using:
L : the part longest dimension.
V : the part speed (or the bowl rotating speed x 3.14 x bowl rim diameter).P : the percentage of parts that will be in the desired orientation.
R = P V / L
A large bowl rim diameter will give time and space for the parts to be qualified and oriented. So bigger bowl means higher rate.
-
www.packexone.com 4
Phase 1 General geometry (3)
Components (exploded view)
Tooling support
Tooling backup ring
Outer shell
Cone
Rotating disc
Disc hub
Rotating bowl
Bowl hub
Base
Shell attachment
Leveling foot
-
www.packexone.com 5
Phase 1 General geometry (4)
Components (section view)
Static hub fixed on base
Ball bearings
Roller chain & sprocket
The bowl has a spherical inner surface. This allows the disc to rotate in an inclined orientation and maintains a small gap with the bowl around its perimeter
-
www.packexone.com 6
Phase 1 General geometry (5)
Components (section view)
Roller chain & sprocket
Disc gearmotor
Bowl gearmotor
Torque limiter
Chain tensioner
-
www.packexone.com 7
Phase 2 Drive design (1)
Drive
The drive is the assembly of components which rotates the disc and the bowl.
The disc rotates within the bowl at a speed that may be equal, higher or lower
than the bowl speed.
A speed difference between bowl and disc is used to improve loading of the bowl rim.
Disc gearmotor
Bowl gearmotor
Chain tensioner
Chain tensioner
Torque limiter
Torque limiter
-
www.packexone.com 8
Phase 2 Drive design (2)
Drive
The static hub is bolted on the base.
The bowl is bolted on the bowl hub which rotates over the static hub.
A large sprocket drives the bowl hub.
Through the static hub, the drive shaft rotates the disc.
Base
Bowl hubSteel: UNS G10200
Drive shaftSteel: UNS G86200
Disc hubSteel: UNS G10200
Ball bearing
Static hubSteel: UNS G10200
Ball bearing
Large sprocket
Small sprocket
Torque limiter
-
www.packexone.com 9
Phase 2 Drive design (3)
Disc drive
The gearmotor drives in rotation all items listed below and the parts carried by
the disc.Gearmotor output speed, Sd = (maximum part speed) / (3.14 x disc diameter) = {rpm}
Gearmotor output torque, Td = (Id + (Wp D2 / 4)) Ad + Tf = {N*m or lbs-in}
where:
Id : total rotational inertia of the items listed below
Wp : weight of the parts carried by the disc.D : disc diameterAd : required disc acceleration after a complete stop.
Ad = 3.14 Sd / (30 td )td : time to accelerate (below 2 sec.)Tf : frictional torque in the bearings
Torque limiter and roller chain are to be selected using this data.
Disc hub
DiscPVC
ConePVC
Driveshaft
Torque limiter
Sprocket Gearmotor
-
www.packexone.com 10
Phase 2 Drive design (4)
Bowl drive
The gearmotor drives in rotation all items listed below and the parts carried by
the bowl.Gearmotor output speed, Sd = (maximum part speed) / (3.14 x bowl diameter) = {rpm}
Gearmotor output torque, Td = (Id + (Wp D2 / 4)) Ad + Tf = {N*m or lbs-in}
where:
Id : total rotational inertia of the items listed below
Wp : weight of the parts carried by the bowl.D : bowl diameterAd : required disc acceleration after a complete stop.
Ad = 3.14 Sd / (30 td )td : time to accelerate (below 2 sec.)Tf : frictional torque in the bearings
Torque limiter and roller chain are to be selected using this data.
Bowl hub
BowlCast aluminum
Bowl floorAluminum: UNS
A96061
Sprocket
Gearmotor
-
www.packexone.com 11
Phase 3 Structure/Tooling (1)
Structure
The structure supports all the rotating components and the outside shell. Its
construction is made of painted carbon steel (UNS K02600). The triangular
geometry allows easy mounting for most components.
Shell attachment
Base plate
Post
Leveling foot
-
www.packexone.com 12
Phase 3 Structure/Tooling (2)
Tooling
The tooling is all the components that qualify/orient the parts: mechanical
stoppers, air jets, pneumatic actuators, rotating wheel, . These components
are mounted on the tooling backup wall which serves also as an external guide.
This wall is mounted to the tooling support, and the tooling support is mounted on top of the outer shell.
Tooling support
Outer shell
Tooling backup wall
top related