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Mechanical Handling Belt conveyor Bucket elevator Apron conveyor Transfer Chutes Airassisted gravity systems Airslide Pneumatic Transport Positive negative pressure systems Fluidcon® FPipe® Mechanical Handling Belt conveyor Bucket elevator Apron conveyor Transfer Chutes Airassisted gravity systems Airslide Pneumatic Transport Positive negative pressure systems Fluidcon® FPipe®

Technical Development Programme for Process Performance Engineers 2010

Heiko Polske

HGRS/MPT-ASA

Terminology

Design Considerations (1/5)

 Belt joint shall be vulcanized

 Trough angle  shall not be less than 30°

 Belt speed:

 The maximum belt speed shall not exceed 2.0 m/s

 Conveyors handling dry fine material (i.e cement) shall not exceed 1.25 m/s

 Belt speed for conveyors less than 50 meters in length shall not exceed 1.5 m/s

 Conveyors longer than 500 m can operate above 2 m/s (Overland Conveyors).

 Trough belt width shall not be less than 800 mm For special applications 650 mm belts may be used

 The minimum distance between the center

of the tail end pulley and the skirt arrangement shall be larger than 2*belt width As a minimum, the skirt should not start until full troughing of belt has been achieved

All sections other

Fig 2: Inadequate design

Fig 1: Belt transition phase

Design Considerations (3/5)

 Idlers:

 Carrier and return idler shall be designed according to DIN (15207-1 / 22107) or CEMA (Class C or greater)

 Carrier and return idler diameter: 100 mm for 650 to 1000

mm belts, 127 mm for belts greater than 1000 mm

 Carrier idler spacing shall not exceed 1250 mm for all belt widths

 High-density polyethylene impact bars at loading points shall be used Rubber protected impact idlers may be used, with spacing of no more than 300 mm for all belt widths

 Return idler spacing shall not exceed 3000 mm for all belt widths

 For conveyors handling sticky materials, return idlers shall

be rubber disc rolls or anti-adhesive rubber tubes

Design Considerations (4/5)

 Pulleys:

 All drive pulleys shall have rubber lagging

 Tail and take up pulleys: rubber lined or spiral wrapped wing pulleys Wing type pulleys without spiral are not acceptable

 Belt tensioning stations:

 For belt conveyors less than or equal to 50 m horizontal center distance, screw tensioning shall be used

 For belt conveyors over 50 m horizontal center distance, vertical gravity or horizontal gravity shall be used

Design Considerations (5/5)

 Skirtboards and dust hood:

 Wear liners shall be installed to the inside and dust hoods shall not extend less than 2 m from loading point

 Skirtboards shall be equipped with adjustable sealing rubber stripes or pads and shall be of the quick release type for easy adjustment

 Carrying Side

 Return Side

Belt training idlers

Belt training idlers

Belt trackers tied off to

the supporting

structure Pivot bearing with simple O-ring seal

Belt Cleaners

Homemade solutions

> in most cases they perform poorly

> can even damage the belt

Belt Cleaner_V-Plough

Idlers to keep the belt flat

Flexible pressure to allow permanent contact with the belt surface

Belt Conveyor

Material accumulated to the pulley surface

High local stress concentration

Skirtboard Seal

Multiple layer seal systems provide best efficiency,

but…

Skirtboard Seal

…before installation make sure there is sufficent seal

distance available

Belt Conveyor

 Sealing blocks, easily adjustable but…

Acceptable as tail seal

Apron Feeder

 Incorrect design of feed chute

Material between chute and side walls

Apron Feeder

Apron Feeder

Chute

Liner

Bucket Elevators

Bucket made from rubber

> Showed best results Buckets completed blocked

Bucket Elevators

Bucket Elevator Casing:

Rubber instead of sheet metall

plates

Belt Conveyor

 Incorrect design of skirtboard

180 mm

Heavy dust emission in tunnel eventhough dust collectors

and edge sealings are installed

Bucket Elevator_Tail pulley

If particles get trapped between the belt and the pulley they

can damage the belt (carcasse & surface) quickly.

> Twin opposed-cone hub with the cones base starting at the centre

> Bars welded to the outer rim

Transfer Chute

 Feed chute located too close to tail end (no skirtboards in transition section !)

Basic principle of pneumatic conveying

Example:Negative pressure system

Vaccum cleaning systems

Feeder Systems

Airlock feeder

Jet feeder Screw pump

Conveying characteristic distribution with fine Wide particle size

shares

Coarse and fine materials, low abrasion

All materials

Max

throughput [t/h] approx 400 220 5Max

conveying distance [m]

approx 1000 250 75

Max pressure difference in conveyor pipe [bar]

 Screw pump

Material Enters Screw

Material Moved

to Mixing Chamber

Modes of pneumatic conveying

 Low solids load ratio

 Represent the majority of systems in industry

 Conveying at high velocity

 Not suitable for erosive and abrasive materials

 Medium solids loading ratio High solids load

 Conveying at low velocity

 Material must be capable of dense phase cov.

 Less abrasion

 Less pipeline wear

 Require less energy

Modes of pneumatic conveying

Dense phase method

Receiving bin Pressure vessel

Supply bin

Dense phase conveying Filter unit

Feeders_How to reduce energy consumption

Rotary valve 1.5 kW

Cement Conveying: Rotary valve replaces screw pump

Screw pump

45 kW

Example from: Merone Plant, Holcim Italy

 Combines pneumatic and air assisted gravity conveying

> Reduced specific energy consumption

Bilder aus Eclepens rein

Fluidcon Instalation at Eclépens plant