Glue preparation
Three days before the start of the lining work, the glue should be prepared in advance. At present, the commonly used rubber compound models are the old model 2572 or 2572-5, and the new model S1002 (from Shenyang Four Oaks). The glue made from this compound is particularly suitable for the combination of metal, hard and soft rubber. The rubber material is in the form of red flakes, and the impurities such as talcum powder on the surface should be removed before use, and cut into strips of 1 2 mm wide and 15 20 mm long. According to the ratio of 1:4 1:8, the cut rubber material is dissolved in No. 120 solvent gasoline (Xinna water can also be used), and the rubber material needs to be fully dissolved during the stirring process, without precipitation and suspended solids.
Metal surface treatment and glue coating
The metal surface after sandblasting and rust removal should be brushed with glue immediately after cleaning (no more than 3 hours to prevent rust). Usually need to be brushed 4 6 times, each brushing interval is subject to the glue drying, drying speed is affected by film thickness, ambient temperature, humidity, ventilation and equipment airtightness and other factors. The last application should be done within 1 to 4 hours before applying the rubber sheet. During the painting process, ensure good ventilation, adequate lighting, and use low-voltage explosion-proof luminaires. Smoking and fire are prohibited on the work site, and the staff should wear gas masks, and the container should be supervised by a special person. After applying the adhesive paste, small pieces or strips of rubber should be used to fill the depressions, holes and sharp corners of the metal surface to ensure that the surface is flat and free of air entrapment. The slurry film should be applied thin and evenly, with a smooth surface free of dust and pores.
Rubber sheet selection and handling
The rubber sheet used for rubber lining shall comply with the regulations of the Ministry of Chemical Industry "HG4-540-67". When cutting the rubber sheet, it should be done according to the shape and size of the lining surface and leave enough lap edges. In order to avoid blanking errors, samples should be made first if necessary. The blanking length of the pipe lining should be less than the inner diameter of the pipe (excluding the seam part), and the total length should be calculated according to the actual size of the pipe plus the flange part of the flange. When seam processing, the edge cutting or lapping method is selected according to the structure of the equipment. When laminating the rubber sheet, the ambient temperature should be kept between 20 and 35 °C. The method of brushing the rubber plate with the glue is the same as that of the metal surface, and it needs to be painted 4 to 6 times. After the last coating of the glue, the dryness of the glue should be judged by touch, and it is advisable to be slightly sticky but not sticky.
Rubber sheet lamination and exhaust
When the glue and rubber sheet are properly dry, roll the rubber sheet upside down (brush the rubber paste facing outward) and spread a clean pad slightly larger than the rubber sheet on top. When entering the container to work, you should wear soft slippers to avoid damaging the adhesive film. When laminating the rubber sheet, fix one end first, then remove the pad while placing the rubber sheet, and flatten the rubber plate by hand, press it firmly and remove the air. In case of wrinkles or large bubbles of rubber board, do not force construction, so as not to affect the lamination effect. The position of the rubber plate should be gently adjusted to remove wrinkles, and the large bubbles can be punctured with a steel needle and the air can be expelled, and then flattened by hand. When lining two layers of rubber board, the seams should be staggered by at least 50mm. Vertical equipment should be lined with a substrate first and then a wall, from bottom to top; Horizontal equipment is lined first and then down; The pipe interface should be edged in the direction of the flow of the medium. After each layer of rubber plate is lined, the excess part needs to be compacted with edge pressing and rolling, and cut off with a skin cutting knife. After that, press the rubber plate vigorously with exhaust pressure roller to remove the small bubbles in time.
Defect repair and vulcanization preparation
When the appearance defects of the lining exceed the regulations, they can be repaired, but the quality of use must be ensured. After each layer of rubber board is lined, the excess part needs to be compacted and cut off with edge pressing. Then roll it out carefully with an exhaust pressure roller, making sure that the air bubbles are expelled in all areas. When the second layer of rubber plate is exhausted, pay attention to only puncture the first layer of rubber plate to avoid damage to both layers at the same time. The method of lining the pipe is the same as above, and sometimes the rubber sheet can be pre-made into a cylinder shape and then put into the pipe lining. When venting, the sand can be pulled out through the rope with a cloth bag to remove the air from the pipe. Finally, in order to prevent air leakage when the rubber plate is punctured, the same liquid glue as the surface layer of the equipment can be brushed on the surface of the adhesive layer to enhance the effect. After checking and confirming that there are no bubbles in the rubber sheet, the seams and laps meet the requirements, and the parts are firmly bonded, the vulcanization preparation can be carried out.