VALVE STEM REPLACEMENT HOW TO
Knowing how the components communicate between them is a good first step into understanding how to troubleshoot. Learning how the components inside of the engine work, is a relatively good thing. But everything is doable and you can learn how these things work. Getting into mechanicals can be a bit difficult for you if you don’t have that background. But what are valve seals? You shouldn’t worry because in this article we are going to elaborate on everything you need when it comes to understanding valve seals and the problems they can make. Divide the depth of the packing chamber by the packing thickness to get the number of packing rings required.Have you experienced something like black smoke coming out of the exhaust? If this is the case, then you probably are experiencing one of the symptoms of bad valve seals. Suggest these two measurements and divide them by two. Measure the inner diameter of the bonnet and the outer diameter of the stem. Insert a stiff wire to measure the length of the valve bonnet. The problem comes when the old packing has lost its properties and the packing comes out in fibers. They just have to be twisted with the special tool to get a grip and then the packing can be pulled out. There are also gland packing extractors available in the market, which are flexible and can be pulled out old packing smoothly. It is very hard in taking out or removing a gland packing can be very difficult sometimes, particularly if it is old and well set, it is necessary to have specially contoured tools. If any leakage is found, tighten the packing further down till leakage stops. Gland packing should not be tightened totally once for all, it is usually tightened to a position 3 to 4mm (1/8’’) below the top end of the packing chamber. This will place the seam of the fourth packing ring position in the same vertical orientation as the first one. Then load the remaining pieces of packing and tighten them securely.Īll gland packing should be located so that the seams are 120 degrees apart from each other. Load the packing to half the death of the packing chamber, and press them down once. Loading all pieces of packing at a time is not advised. Inspection of the stuffing box and the stem is important because both should be clean from burrs, pitting, scoring, or corrosion on its surface. The length of each piece of packing must be sized properly so that both ends may meet one another with the proper, correct dimension. Preferably, with a sharp cutting device or packing cutter, cut the selected packing with a 30 degree to 40-degree at an inclined angle. If no such packing is available, slightly thicker packing will do, but thinner packing is not suggested under any circumstances. In general, the packing should be as thick as half the difference between the valve stem diameter and the interior diameter of the packing chamber or stuffing box. Selection of a proper tool to take out the packing so as not to damage like scratches on the valve stem and valve packing chamber or stuffing box.Ĭlean the valve stem and valve packing chamber properly and carefully from the formation of scratches. It is required to reduce valve operating torque and to prevent stem wear.įirst of all, the correct selection of packing materials is confirmed, so that stem packing is suitable for the maximum working pressure and temperature of the process and the kind of fluid being handled. The stem packing should be replaced preferably every 2 to 3 years even though valves have no failure such as leakage. Replacement Procedure for Valve Stem Packing
There are few main criteria for the selection of valve packing. Stem packing is a type of seal, damps leakage between moving part and housing, is essential for the control valve.
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