| 摘要 |
The invention is concerned with a method and apparatus for cleaning viscous materials, wherein the viscous materials are passed in the molten condition under pressure through a movable strip-shaped screen having an upstream face which retains impurities. The pressure of the viscous material against the upstream face of the strip-shaped screen is reduced when the latter is obstructed by the impurities it retains. The sealing pressure between the strip-shaped screen and a first chamber which feeds the molten material through the strip-shaped screen and a second chamber which receives the filtered molten material is temporarily eliminated, and the strip-shaped screen is moved crossways with respect to the direction of flow of the viscous material to replace a soiled area of the screen by a clean area and then it is immobilized. The first chamber, screen and second chamber are resealed together, the molten material upstream of the screen being simultaneously repressurized, and filtering of the material through the strip-shaped screen is continued. The reduction of the pressure of the viscous material is achieved by increasing the original volume of the first chamber supplying the molten material to the strip-shaped screen, and repressurization of the viscous material is accomplished by restoring the first chamber to its original volume. |
