Eclipse ThermJet TJ0015 - 2000 Technical Information

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Eclipse ThermJet TJ0015 - 2000 Technical Information Manual pdf 14 page image

14ThermJet, V2, Technical Information, Edition 2.14Step 4: Flame Monitoring SystemA flame monitoring system consists of two main parts:• A flame sensor• Flame monitoring controlFlame SensorThere are two types that you can use for a ThermJetburner:• UV scanner• Flame rodA UV scanner can be used with all combustor types.The UV scanner must be compatible to the flamemonitoring control that is used. Refer to the manual ofyour selected control for proper selection of the scanner.NOTE: Flame rod option is not available for the TJ300 andlarger.• The standard flame rod is used with natural gas,propane, butane and pre-heated air up to 300ºF.You can find more information in Info Guide 832.Flame Monitoring ControlThe flame monitoring control is the equipment thatprocesses the signal from the flame rod or the UVscanner.For flame monitoring control you may select severaloptions:• Flame monitoring control for each burner: if oneburner goes down, only that burner will be shut off• Multiple-burner flame monitoring control: if oneburner goes down, all burners will be shut offEclipse recommends the following:• Trilogy series T600; see Instruction Manual 835• Bi-flame series; see instruction manual 826• Multi-flame series 6000; see Instruction Manual 820• Veri-flame; see Instruction Manual 818If other controls are considered, contact Eclipse todetermine how burner performance may be affected.Flame monitoring controls that have lower sensitivityflame detecting circuits may limit burner turndown andchange the requirements for ignition. Flame monitoringcontrols that stop the spark as soon as a signal is detectedmay prevent establishment of flame, particularly whenusing UV scanners. The flame monitoring control mustmaintain the spark for a fixed time interval that is longenough for ignition.DO NOT USE the following:• Flame monitoring relays which interrupt the trial forignition when the flame is detected• Flame sensors which supply a weak signal• Flame monitoring relays with low sensitivity■ A UV scanner can possibly detect anotherburner’s flame if it is in the line of sight, and falselyindicate flame presence. Use a flame rod in thissituation. This helps prevent accumulation ofunburned fuel which, in extreme situations, couldcause a fire or an explosion.Step 5: Combustion Air System (Blower &Air Pressure Switch)Effects of Atmospheric ConditionsThe blower data is based on the International StandardAtmosphere (ISA) at Mean Sea Level (MSL), whichmeans that it is valid for:• Sea level• 29.92" Hg (1,013 mbar)• 70ºF (21ºC)The makeup of the air is different above sea level or in ahot area. The density of the air decreases, and as a result,the outlet pressure and the flow of the blower decrease.An accurate description of these effects is in the EclipseCombustion Engineering Guide (EFE 825). The Guidecontains tables to calculate the effect of pressure, altitudeand temperature on air.BlowerThe rating of the blower must match the systemrequirements. You can find all the blower data in: Bulletin/Info Guide 610.Follow these steps:1. Calculate the outlet pressure.When calculating the outlet pressure of the blower,the total of these pressures must be calculated.• The static air pressure required at the burner• The total pressure drop in the piping• The total of the pressure drops across the valves• The pressure in the chamber (suction orpressurized)• Recommend a minimum safety margin of 10%WARNING