Flame Eye/Detector in Gas Turbine


Thread Starter


Please what kind of Flame eye/Flame Detector is used in a gas turbine furnace and what is the mode of operation?

Please explain in the simplest form i can understand.

The least expensive type of flame detection system used in most gas turbines is done using an ultra-violet (UV) sensor. The sensor is charged to a high voltage (sometimes as high as 335 VDC) and when it sees flame the sensor shorts itself to produce a saw-tooth output (pulse rate) which is proportional to flame intensity.

The sensor can be connected to a module (that provides the necessary operating voltage) and when the pulse rate exceeds a small value the module changes the state of an internal relay which has contacts which can be connected to the gas turbine control system to indicate the presence (or absence) of flame.

These types of flame detectors/sensors are often called Geiger-Mueller types of sensor. A common producer/manufacturer of them is Honeywell.

You can use your preferred World Wide Web search engine to search for results to "UV flame detector" or "UV flame sensor" or "Geiger-Mueller flame sensor" (all with the double quotes). You should find many relevant results which will be very helpful. Some even might include the ever-endearing YouTube videos which may be quite entertaining if not so informative.

Hope this helps!
hi all,

i want to ask about how i can immigrate flame detector LG1093AA
FROM MARK2 TO MARK 6. what are the methods be i follow?

What kind of flame sensors are currently used on the Mark VI?

I believe if you look in GEH-6421, Vol. II, The Mark VI System Guide, in the VTUR section's TRPG description, you will see how these Honeywell LG1093AA Geiger-Mueller type flame sensors can be connected to a Mark VI--<b>if the 335 VDC option cables are provided with the Mark VI and the Mark VI rack-mounted power supplies.</b> The Mark VI can have them directory connected to it--but only if the option was provided (rack-mounted power supplies have to have the capability for the cables to connect to the TRPG to power this type of sensor).

Many Mark VIs provided with new turbines use the Reuter-Stokes Flame Trakkers--which are 4-20 mA devices, and connect directy to TBAI cards which provide the power. The Honeywell LG1093AA flame detectors require 335 VDC to operate--and the Mark* input circuit must be able to convert a frequency input to flame intensity.

There is a third option, which is rarely used, but is a workaround of sorts. The flame detector system used on a Mark II used an interface module that converted 28 VDC to 335 VDC and which looked at the frequency feedback (flame intensity) and when the counts exceeded a low value changed the state of an electromechanical relay in the module to indicate the presence of flame. That discrete output was connected to a special discrete input of the Mark II, and when it closed the Mark II indicated the presence of flame, and when it open the Mark II indicated the loss of flame.

The module from the Mark II could be moved to the Mark VI, and powered with 28 VDC (from some source--I don't know if the Mark VI can provide the power, or if you would have to supply a power supply (which should be powered by 125 VDC to produce 28 VDC to power the interface module). The LG1093AA could be connected to the interface module, and the discrete output of the interface module could be connected to an unused discrete (contact) input of the Mark VI which would have to be configured to serve as a flame indication. LOTS of work.

In either case, migrating this type of sensor to a Mark VI that wasn't already using this type of sensor for flame detection would require modifications to Toolbox configuration and downloads and re-boots and CIMPLICITY project changes--and it could get VERY ugly, very quickly. I don't recommend this for the novice user, and for ANY user there should be a complete hard-drive image back-up which could be used to restore in the event of problems (and there will likely be problems--the only unknown is the extent of the problems, and the time required to recover from them).

If you are having problems with the existing flame sensors/detectors perhaps if you described them here we might be able to offer some suggestions.

Hope this helps!

>Can an off the shelf Honeywell LG1093AA be hooked up
>directly to the PTBA in a Mark 5?

That's what the Mark V was designed to work directly with. The Mark V produces--and reads--335 VDC, so there is no need for an interface module.

The only other flame detector I have ever seen used with a Mark V are the Reuter-Stokes Flame Trakkers--and they had to have an interface module connected between the Flame Trakkers and the Mark V. Because the Reuter-Stokes uses 24 VDC to produce 4-20 mA signals which are proportional to flame intensity--but the Mark V MUST have flame detectors connected to the PTBA and it can only do the 335 VDC signal. So, the R-S interface module was used to produce a frequency output that could be connected to the 335 VDC input terminal(s) the Mark V could use for flame intensity, and hence flame logic signals.

As far as I know, flame detectors can ONLY be connected to the PTBA--unless someone has come up with a really nifty work-around. Are you trying to replace a failed Reuter-Stokes Flame Trakker system?

The BIG caveat with the Honeywell UV flame detectors is they are polarity sensitive!!! You can connect them incorrectly (wrong polarity) and they will be fine--UNTIL they see a flame! And, then they go POOF! So, be sure of the polarity when you connect them!!! DO NOT rely on the conductor colors of the wires between the Mark V and the turbine compartment--they are quite often "wrong" (red might be negative and black might be positive; and I think the wire colors on the Honeywell are black and white--and I don't recall which is supposed to be connected to positive and which to negative!). Just make sure to check everything--carefully! It is 335 VDC, though it's a very low current, it WILL get your attention VERY quickly if you get a shock!

Hope this helps! I'm interested to know if the unit doesn't have Honeywell UV flame detectors now, what are you trying to replace? (Just curious; that's all.)