Predicting a machine's failure by monitoring operating conditions

Machines and structures operate in environments that can impact their reliability. Sometimes it is easier to monitor this operating environment than to monitor the machine or structure directly. Of particular importance is detecting when a machine or structure is forced to operate outside its design envelope, a situation that may greatly increase the probability of premature failure. Operation environment parameters include:

• climatic conditions including wind speed, wind direction, temperature and humidity
• airborne dust levels
• airborne corrosive materials
• airborne explosive materials
• equipment operators, rough or inappropriate use of equipment
• failure of auxiliary equipment
• process feed stock contamination, variation or out of specification
• seismic activity
• electricity supply brown-outs or harmonic content
• fuel contamination

By monitoring one or more of these parameters, risks can be identified, inspections or tests conducted and corrective action taken.

Climatic conditions

Temperature and humidity extremes can cause failure. Both these parameters are easily monitored.

Airborne dust levels

Particle sizing and counting can provide an indication of likely problems in some circumstances.

Airborne corrosive materials

Corrosive acid vapors and airborne salts can induce problems of corrosion and contamination of lubricants.

Airborne explosive materials

Gas and inflammable material in the form of fine powders can cause destructive explosions or fire.

Rough or inappropriate use of equipment by operators

Abuse by operators is a major cause of machine failure. The abuse may be in the form of inappropriate feed stock, maintenance short-cuts, failure to adhere to operating procedures, sabotage and failure to recognize abnormal conditions.

Failure of auxiliary equipment

Auxiliary pumps, filters, feed-stock preconditioners, power supplies, cooling systems, etc. can be direct cause of failure.

Process feed stock contamination, variation or out of specification

Water conductivity, pH, and solid matter in fluids, etc can cause breakdowns.

Seismic activity

Particularly important for large structures not designed to withstand 1-2g loadings.

Electricity supply brown-outs or harmonic content

Many industrial machines behave badly when the power supply is significantly lowered. Electric motors can stall and draw large destructive currents under these conditions. Cooling pumps may be unable to provide effective heat extraction.

Fuel contamination

Contaminated fuel can be very destructive of internal combustion engines. Combustion produces in boilers can cause insulating deposits resulting in poor performance.