GENERAL INFORMATIONThis document provides the specification for handling, manufacturing and packing of the wire type emitting electrodes. It includes drawings of the electrode assembly, the reinforcingtube, details of the hook dimensions, and the fixture for forming the electrodes. The manufacture of the emitting electrodes is based on drawing V3570004 Rev “B” with the modifications shown on drawings CS-444-15-111 and CS-444-15-112 and described in this specification.
MANUFACTURING PROCEEDURESpiral Electrode With Hook 1. Check that the marking of the wire is in accordance with the actual material specification; 2. After unpacking, the wire must be handled so that no surface damagesoccur; 3. Defects on the wire, such as snarls and joints, have to be cut away; 4. When coiling the wire to a spiral, check that the tool does not cause scratches on the wire. Lubricant used at coiling must not contain chlorides; 5. The spiral electrode must be tightly coiled. 6. When cutting the wire after coiling, check that no deformation and burrs occur on the wire ends; 7. At the forming of the hook, check that the centre line from the arc-formed part of the hooks coincides with the centre line from the straight, unstrengthened part of the wire; 8. Check during the compressing of the tube around the wire, (only hard drawn wire) that the jaws on the press tool press the tube uniform, and that all jaws press the tube to a firm fit-up against the wire; 9. Spiral electrodes from each individual wire coilmust be kept apart and marked with coil number.
HANDLING INSTRUCTIONThe spiral needs every possible fraction of its strength. The strength can be reduced in a number ofways: 1. Kinks on the wire. Every unnecessary bending of the wire is evil; 2. Scratches give break indications. You can cut glass by using a diamond causing a smallscratch in the glass. The hard drawn stainless wire is in a similar way sensitive to scratches. Sharp marks from tools will undoubtedly lead to an early break. Use ‘soft gloves’; 3. The wire end is formed as a curve to make the hook and the coil centerlines coincide. Animproper forming will give a mis-alignment between the wire end and the stretchedelectrode. This is an unnecessary extra stress; 4. If the tube is pressed on with too much force the wire will be deformed improperly and thus weaker. The tube is not to be pressed when annealed wirematerial is used. Burrs or dirt in the hole of the tube may give marks and scratches in the wire when pressing. If the force, when pressing, is too small, there will be a loose fit between tube and wire. Sucha loose fit will cause electrical wear and the wire will only last a few weeks instead of manyyears. Depending on stainless grade selected, the wire is very sensitive to chlorides e.g. differentkinds of salt or storing in seaside atmosphere. Such corrosion can only be discovered using amicroscope before the wire falls apart. Cleanliness is a must when transporting, storing, and
Packing MaterialThe emitting electrodes are packed in wooden boxes (Quantity Per Box : 500 – 600 Pcs maximum).The boxes must, on the inside, bedressed with plastic sheets or waterproof paper.
Packing and LoadingThe emitting electrodes are piled in rows in the boxes. A cardboard sheet or similar separator if required to keepthe electrodes from hooking into each other separates each pile. By overseas transport,corrugated cardboard must be placed between each electrode layer. If a box is notcompletely filled up, the remaining space is filledout with packing paper or similar.
TESTING INSTRUCTIONThis document provides the specification for testing of the wire type emitting electrodes and the material from which they are fabricated. There are 5 Tests to be performed on the electrodes :- Visual Inspection- Check any gross defects which could impact their service life & the dimensional check on the fabrication drawings. Tension Test of the elongated Electrode – It indicates the electrodes ability to self-tension & maintain its position in the precipitator. Metallurgical Testing – It will verify the material used in the electrodes. Generally trust on SS Wire SS 904L / 316L / SS 2343 Manufacturer Material Test Certificates.
Visual Inspection InstructionsVisual inspection of the electrodes will determine the condition of the electrodes with respect to thefollowings :-- · Kinks in the wire. · Scratches from the fabrication tools. · Misalignment between the hook & the coil centerlines. · Deformationof the wire where the tube is pressed on. · Loose fit between the tue& the wire at the swage. · Burrs or dirt in the hole of the tube.
Dimensional CheckOverall length of the coiled section of the electrode, dimension “B” is to be verified as shown on drawing V3570004, Rev B. Dimension of the Hooks are to be checked in respect to drawingV-3570004.
Tension Testing InstructionsTesting of the electrode initial tension requires that the electrode be stretched between a stationary attachment point and a tension-measuring device. Stretch the test specimen using the following steps :- 1. Hook one of the ends of the discharge electrode to one of the attachment points. Pull out the electrode & attach it to the other point. It is essential that the discharge electrode can spin freely during the elongation. The electrode must not be stretched out longer than exactly needed to make the hook up. Check that the electrode sits parallel to the tension-measuring device when installed. 2. The elongation of an emitting electrode shall always be done with a tool, which grips the hook, obtaining an even stretching along the whole spiral. The tool shall be able to allow to follow the free spinning electrode during the whole extractionoperation. The tool must not slide against anything or be guided in any other way.
Sailen Baidya (16.01.2012) B.N.Chakraborty (16.01.2012)