Manual D-LX-700 en.pdf - Durag Group

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Page 16 D-LX 700 11. General Information about the D-LL 703 Fibre Optic System The D-LL 703 fibre optic system consists of a fibre optic bundle including the lens system (D-FO 703), an inner carrier assembly with purge air connection and the threaded flame scanner mount (D-IC 703), and an outer carrier assembly including cooling air connection and mounting flange for welding (D-OC 703). The forward section of the D-LL 703 fibre optic system carrier components is flexible. This allows the scanner to monitor the flames of tilting burners. In these applications, the flange of the outer carrier assembly should be welded to the moving portion of the burner facing the flame. If the burner is moved up to a new location to distribute heat, the scanner will be automatically adjusted to the new flame location. Another suitable application for the fibre optic system is for installations that do not have a direct line of sight from the flame scanner to the burner flame. These fibre optic systems are available for two different spectral ranges: the UV flame scanner D-LX 703 UA/UAF is compatible with the D-LL 703 UV xx fibre optic systems, and the IR flame scanner D- LX 703 IG/IS is compatible with the D-LL 703 IR xx fibre optic system. The lens system receives the light from the flame and concentrates it through the fibre optic. The fibre optics transmits the light directly onto the photo element inside the D-LX 700 flame scanner. 12. Mounting the D-LL 703/704 Fibre Optic System To achieve optimal, selective flame monitoring, the correct position must be used to mount either the welded flange of the D-LL 703 outer carrier tube (flexible system) or the D-LL 704 unit (rigid system). The sensor must be able to view the flame at any load within the range of the burner. The flame sensor should also be positioned such that the distance to the selected flame is as short as possible, and the distance to neighbouring flames is as great as possible. The viewing angle of the flame sensor should capture the lower third of the flame (the root). When selecting the correct position, it is important to accommodate any normal flame migration, particularly for coal-fired burners. The viewing axis should not cut through the flames of any neighbouring burners. Two ½" internal threads have been provided on the fibre optic system, one as a purge air and another as a cooling air connection. Purge air must be supplied to keep the lens free of possible particulate accumulation. Therefore, the purge air should be connected to the inner carrier assembly. Only oilfree, filtered, compressed air should be used for purging. The D-LL 703 has a connection for cooling air on the outer carrier tube. Enough cooling air should be supplied to insure that the permissible ambient temperature for the fibre optics is not exceeded. If the ambient temperatures are too high in installations using the D-LL 704 system, a guide tube should be provided on site that can supply cooling air to the system. The necessary flow rate, air volume, and pressure required for the cooling air supply must be determined on a site-specific basis. These specifications depend on the ambient temperature, the length of the fibre optic system supplied, the diameter of the guide tube at the burner, and the temperature of the available cooling air. The length of the fibre optic section exposed to higher ambient temperatures must also be taken into account. For example, when a section of the fibre optic bundle is exposed to the heat from the main burner, less cooling air is required than if the entire length of the fibre optics were exposed to the heat radiating from the main burner or heated combustion air. When the ambient temperature inside the burner exceeds the permissible ambient ! temperature of the fibre optic, sufficient cooling air must be supplied at all times. A failure to meet these criteria can damage to the fibre optic conductors. The welding flange on the outer guide tube of the D-LL 703 fibre optic system needs to be welded near the flame in the burner assembly, aligned so it has a clear, precise view of the flame. If possible, the combustion air supply (primary or secondary wind box) area should be used as the mounting location. ! To prevent damage to the fibre optic conductors when welding the mounting flange into place, the internal support tube and fibre optics should be removed from the outer carrier tube before welding.
D-LX 700 Page 17 The back end of the outer carrier assembly must be secured at the burner plate, either by directly welding it into place or using the D-ZS 703 mounting flange. When the main flange is tightened, the cutting ring will form a pressure-seal with the rigid portion of the guide tube. After the outer carrier assembly is installed, the inner carrier assembly with the fibre optics can simply be reinserted into the outer carrier and secured with the hex nut. The carrier tube (both inner and outer) have specific, factory-determined length ! tolerances and are to fit to each other during production. If these guide tubes are switched during installation, the mounting rings may need to be repositioned. After unscrewing the two M4 screws in the mounting ring, this ring can be moved. This ring must be positioned so that the beginning of the fibre optic holder is held against the welded flange. The outer guide tube should compress the inner carrier tube slightly to make sure that the holder for the fibre optics is kept in front of the welded flange when the tube moves. The D-ZS 703 can be used to secure the D-LL 703 fibre optic scanner to the burner plate. The mounting flange D-ZS 702 or the D-ZS 704 welded flange can be used to secure the D-LL 704. Once the internal carrier tube is installed, the mounting ring can be used to mount the flame scanner. It is important to make sure the surface of the photo element does not become damaged, since the housing does not directly protect it. Once the mounting ring is tightened into place, the setscrew should also be tightened down. When laying the flexible section of the D-LL 703 outer guide tube, the radius of any curves or bends should not be less than 300 mm. The fibre optics can withstand curves with a radius as small as 190 mm without permanent damage, but the internal guide tube will not be able to slide properly for insertion or later movement. For application with tilting burners, these guidelines should also be fulfilled so that a large enough radius for any bends is provided at all burner positions. The fibre optics should also be installed with enough slack that the burner’s movements do not stretch the outer carrier tube. LE703-03-001 (Fig. 9) Laying the outer carrier tube of the D-LL 703 12.1 Installing the fibre optic system in tilting burner applications When determining the installation position and angle of view of the D-LL 703 fibre optic system relative to the flame (particularly for coal flames whose combustion may occur away from the main burner), it is important that the monitored flame surface remain the same while the burner tilts. The following drawing (fig. 17) shows an example of a changing viewing range of a tilting burner. Generally, oil-fired burners are designed so that the fibre optic system can be mounted parallel to the oil-atomisation nozzle in the tilting burner head. In this location, there are no significant changes to the viewed flame range of the scanner system as the burner moves. For coal-fired burners, however, the fibre optic system must usually be built into the wind box above the burner. This causes significant changes in the portion of the flame being observed as the burner tilts.
Page 1 and 2: English 03/2005 Fibre Optic System
Page 3 and 4: D-LX 700 Table of Contents 1. Gener
Page 5 and 6: D-LX 700 Page 1 1. General Informat
Page 7 and 8: D-LX 700 Page 3 3. Functional Descr
Page 9 and 10: D-LX 700 Page 5 If the cause of the
Page 11 and 12: D-LX 700 Page 7 7.1. Setting the Fl
Page 13 and 14: D-LX 700 Page 9 7.3. Setting the Am
Page 15 and 16: D-LX 700 Page 11 9.2. Selection Cri
Page 17 and 18: D-LX 700 Page 13 10.3. D-LX 700 Dim
Page 19: D-LX 700 Page 15 10.4.1. Cable and
Page 23 and 24: D-LX 700 Page 19 13. Purge and Cool
Page 25 and 26: D-LX 700 Page 21 14. Technical Data
Page 27 and 28: D-LX 700 Page 23 17.2 Uninstalling
Page 29 and 30: D-LX 700 Page 25 LE703-12-001 (Fig.
Page 31 and 32: D-LX 700 Page 27 18.3 Mounting the
Page 33 and 34: D-LX 700 Page 29 20. Dimensional Dr
Page 35 and 36: D-LX 700 Page 31 22. Optional Acces

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