Description of cylinder leakage treatment method

Cylinder leakage treatment method;

1. The joint surface with large cylinder deformation or serious steam leakage, using the method of grinding the joint surface

If the upper cylinder joint surface is deformed within the range of 0.05 mm, the above cylinder joint surface is used as the reference surface, and the lower cylinder joint surface is coated with red dan or embossed blue paper, and the lower cylinder is scraped according to the trace. If the deformation of the joint surface of the upper cylinder is large, apply red Dan in the upper cylinder, and develop the trace with a large flat ruler to level the upper cylinder. Or use the mechanical processing method to level the upper cylinder joint surface, and then use the above cylinder as the reference to scrape the lower cylinder joint surface. There are two ways to grind the cylinder joint surface:

(1) It is a bolt that does not close the joint surface. The jack is slightly pushed forward and backward to move the upper cylinder, and the scraping is carried out according to the condition of the lower cylinder joint surface red dan. This method is suitable for a high-pressure cylinder with a strong structural rigidity.

(2) It is a bolt with tight joint surface. According to the tightness of the joint surface of the feeler gauge, the value and the trace of the extrusion are measured, and the joint surface is repaired. This method can eliminate the influence of the vertical arc of the cylinder on the gap.

2. Use appropriate cylinder sealing material

    Because there is no uniform national standard and industry standard for steam turbine cylinder sealant, the raw materials and formulas are also different, and the product quality is uneven. When selecting the cylinder sealant for steam turbine, it is necessary to choose the reputation in the industry. Guaranteed regular manufacturers to ensure the tightness of the cylinder after maintenance.

3. Local repair welding method

    Since the cylinder joint surface is washed by steam or corrodes the groove mark, the groove is added with a suitable electrode, and the mark is made with a flat plate or a flat ruler, and the weld bead and the joint surface are in the same plane. When the cylinder joint surface is deformed greatly or the steam leakage is serious, one or two 10-20 mm wide dense clearance gap seals are repaired on the joint surface of the lower cylinder, and then measured with a flat ruler or a buckle cylinder, and painted with a red pencil. Until the gap is eliminated. The process of this operation is also very simple, preheat the cylinder to 150 ° C before welding, and then perform partial reflow or jump welding at room temperature. Use austenitic electrodes, such as A407, A412, and use asbestos cloth to cover the insulation and slow cooling after welding. After the room temperature is cooled, the sanding is performed.

4. Coating or spraying of the cylinder joint surface

    When the cylinder joint surface leaks in a large area and the gap is about 0.50 mm, in order to reduce the workload of the scraping, a coating process can be used. The cylinder is used as the anode, the coating is used as the cathode, and the electrolytic solution is repeatedly applied on the joint surface of the cylinder. The thickness of the coating depends on the gap of the cylinder joint surface. The type of the coating depends on the material of the cylinder and the shaving. Process depends. Spraying is to use a special high-temperature flame spray gun to heat the metal powder to a molten or plastic state and then spray it onto the treated cylinder surface to form a coating method with the desired properties. The utility model has the advantages that the equipment is simple, the operation is convenient and the coating is firm, and the cylinder temperature after spraying is only 70 ° C - 80 ° C does not cause deformation of the cylinder, and a heat-resistant, wear-resistant and corrosion-resistant coating can be obtained. It is noted that the cylinder surface should be ground, degreased and pulled before application and spraying. After the application and spraying, the coating should be ground to ensure the tightness of the joint surface.

5. Bonding method

    If the local gap leakage of the bonding surface is not very large, the 80-100 mesh copper mesh may be heat-treated to reduce the hardness, and then cut into an appropriate shape, placed on the leakage surface of the bonding surface, and then equipped with a cylinder sealant. If the gap between the joint faces is large and the leakage is serious, a groove of 50 mm deep and 5 mm wide may be opened in the upper and lower joint faces, and a toothed pad of IGr18Ni9Ti is embedded in the middle, and the thickness of the toothed pad is generally about 0.05-0.08 mm larger than the depth of the groove, and It can be adjusted with stainless steel gasket of the same shape.

6. Method of controlling bolt stress

    If the deformation of the cylinder joint surface is small and uniform, replace the new bolt with a gap or increase the preload of the bolt appropriately. Fasten the bolts from the middle to the two sides at the same time, that is, from the vertical arc * or the place where the force is deformed * large. Theoretically, the pre-tightening force of the control bolt can be calculated by the formula d/L≤A, but since the data and measurement methods of this calculation are still under study, it has not been promoted at present, and it is mostly within the allowable *large stress of the bolt. Based on experience.