Cleaning before sand blowing and spraying - organic solvent cleaning and degreasing

       Organic solvent cleaning and degreasing is a degreasing method that uses organic solvents to dissolve grease to remove oil stains on the surface. Commonly used solvents are kerosene, gasoline, alcohol, toluene, acetone, trichloroethylene and carbon tetrachloride. This method is characterized by simple operation, strong adaptability, basically no corrosion of metals, and can remove both saponified and unsaponifiable oils. The disadvantage is that some solvents are flammable and have certain toxicity. Commonly used degreasing cleaning methods include soaking and brushing method, spray degreasing method, steam washing method and combined method.



    (1) Soak brushing method. Immerse the workpiece in the solvent, remove oil stains by mechanical stirring and brushing. ,

    (2) Spray degreasing. The solvent is sprayed on the surface of the workpiece through the nozzle, and the solid dirt in the grease phase is removed under the scouring action of the solvent. After spray degreasing, it is generally followed by rinsing with a clean solvent.

    (3) Steam washing method. The organic solvent is placed at the bottom of the airtight container, the workpiece is suspended on the organic solvent, the solvent is heated, the steam generated by the organic solvent condenses into a liquid on the surface of the workpiece, the grease is dissolved and falls back to the bottom of the container together with other dirt to remove the workpiece. Oil stains on the surface.

    (4) Union Law. Combined degreasing by dipping and steam, or combined degreasing by dipping-spraying-steam, the effect is better. The three-tank degreasing process using trichloroethylene as the solvent has the best degreasing effect. The parts are heated and soaked in the first tank to dissolve most of the grease; in the second tank, use a relatively clean solvent to remove the residual grease and dirt on the workpiece; finally, steam degreasing in the third tank. When the trichloroethylene vapor comes into contact with the cold part surface, it condenses into a liquid and dissolves the residual grease on the part surface, and then flows back into the tank. This cycle can remove the grease on the surface of the part. Due to the high density of trichloroethylene, it is not easy to overflow from the slot. There should be a cooling device on the upper part of the oil removal tank to condense the remaining trichloroethylene vapor. If ultrasonic waves are added to the bottom of the first groove, the separation of grease and dirt can be accelerated, especially the polishing paste can be quickly removed. If a spray device is installed, large particles of dust, powder, etc. can be quickly washed away.