Vacuum press

Plastic molding of bricks, pipes, tiles is carried out from plastic clay masses with a humidity of 18-22% by extrusion through profiled mouthpieces of tape screw (screw) presses. There are vacuum (SM-1098, SMK-133, SMK-28, SMK-443A, etc.) and vacuum-free SM-58, SM-294, SMK-21) presses consisting of a body, screw mechanism, drive, head and mouthpiece.
For the manufacture of ordinary clay bricks, low-melting clays of medium to moderate plasticity are most suitable. The finished molding mass is taken from the mixer by means of a feed screw and moved to the vacuum chamber. Before feeding into the vacuum chamber, the clay mass is compacted in the conical part of the mixer, fills its outlet part, passes through the annular hole and is cut with knives into layers of small thickness (10-15 mm). In the vacuum chamber there is deaeration (removal of air) of the mass, which by means of the feed roll is supplied to the screw screw of the press, passes through its body and is pushed through the press head and mouthpiece. When forming ordinary brick, the mouthpiece has a rectangular section, and when making hollow stones in the mouthpiece of the press, a hollow-forming core is installed, consisting of a bracket, rods and cores (nozzles), forming holes; in the articles. Shaped inserts in the form of narrow slit are used to form tiles, and circular ones are used for ceramic pipes. Mouthpieces during vacuum pressing of full-white brick are made with steel or cast iron with a length of 150-300 mm and a taper of 4-16% (Figure 7). The length and taper of the mouthpiece depend on the quality of the raw material.