Troubleshooting Practice Trouble Shooting Trouble Possible Cause Line

Troubleshooting Practice

Trouble Shooting Trouble Possible Cause Line Plug 1. Loss of conveying air a. Plugged inlet filter b. Worn air supply c. Non seating relief valve d. Relief valve setting too low e. Leakage of air through 1. Rotary feeder 2. Pressure tank valves 3. Pipe couplings 4. Diverter valves 2

2. Filled receiver vessel 3. Material coating conveying line inside 4. Change in material being conveyed a. Moisture b. Particle size 5. Increased feed rate, worn orifices 6. Obstruction in conveying line 3

Inadequate Capacity – for Systems which used to meet capacity 1. Worn equipment a. Air lock with increased leakage b. Blocked or plugged aeration media 2. Plugged venting system 3. Changed material characteristics 4. Material feed blocked by foreign material 4

Line Plug For Systems which never worked 1. Inadequate air supply a. volume-below saltation velocity with fan air supply b. pressure – inadequate pressure for system 2. Material Characteristics a. Sticky b. Very fine (less than 5 microns c. Picking up moisture 3. Line configuration a. several bends in series b. sloping line with 2 -phase flow c. vertical rise to close to pick-up 4. Unsteady material feed rate 5

Inadequate Capacity – to increase operating system capacity 1. Modify air supply quantity a. stream flow system –reduce air volume to minimum steady conveying. b. Two phase flow – increase air volume to reduce slugging c. Dense phase – increase air volume 6

2. Modify air supply pressure a. Increased system capacity may require increased pressure 3. Change line configuration a. Shorten line length b. Eliminate bends c. Increase line diameter for stepped line at end of system 7

• Excessive line Wear – Reduce conveying velocity – Use “tee” bend – Increase material to air ratio – Step pipe diameter through system – maintain constant velocity through system 8

• Material Breakage – Reduce conveying velocity – Eliminate bends, cyclones, impact points – Reduce velocity before terminal points of system. 9

• Controls – Keep them simple Requires trained maintenance person Eliminate all unnecessary interlock Common problems: 1. Solenoid valves 2. Limit switches 3. Level indicators 4. Plugged pressure taps 5. Dirty electrical contacts 10