Abstract: For desanding castings cast in moulding sand by means of at least one fluid pressure pulse acting on the sand mould, the fluid is bundled into at least one cutting jet and the latter is made to act directly on the sand mould.

Abstract: A process for compacting foundry molding material is proposed, the molding material being introduced into a molding device with a pattern plate with a pattern frame and a molding and filing frame mounted on it, by means of a compressed gas, the compressed gas being used at least for precompaction, the pressure surge used for the precompaction being released into the molding floor with a low, then a higher pressure gradient.

Abstract: The device comprises a pressure housing for storing a gaseous medium under pressure, a pattern plate for supporting a pattern, and a molding box of height H associated with the pattern plate and defining therewith a molding space for receiving the granular molding material to be compacted. A valve separates the pressure housing from the molding space, and selectively communicates the gaseous medium in the pressure housing with the molding space for compacting the granular molding material. A mechanical compaction plate is mounted in the molding space and defines with the pattern plate a volume of dead space. An adjustment element varies the volume of the dead space.

Abstract: The invention relates to a process for the compression of molding sand in casting molds having a pattern plate with a pattern arranged therein. The molding sand is introduced loosely into the molding space located above the pattern plate and is thereafter fluidized to a final pressure of 20 bar maximum by means of a compressed-air surge acting on the molding sand followed by compression, by mechanical pressing. The process of the present invention provides a smooth pressure surge which is subdivided into at least a two part gradient in its pressure-rise time curve, so that the first part of the pressure-rise gradient takes place from 0.3 to 18 bar/sec to a pressure P.sub.1 and the second part has an increased pressure-rise gradient which takes place from 18 to 95 bar/sec. to a pressure P.sub.2 where P.sub.1 <P.sub.2 .ltoreq.20 bar. Subsequently, the P.sub.2 pressure is reduced in an essentially controlled manner, with a pressure-reduction gradient of a minimum of 3 bar/sec.

Abstract: The molding apparatus includes a pattern plate carrier for air-pressurized compaction processes. The carrier is equipped with air venting structure running along the inner contour of the mold box of the sand molding apparatus in the form of elongated slotted bars.

Abstract: Foundry moldings are manufactured in an economic manner without increasing cycle time comprises a 3-stage method including the steps of feeding the molding material by means of compressed air into a molding container and thereafter precompressing the molding material by applying a pressure surge to the surface thereof and thereafter recompressing said precompressed molding material to final compression. The resulting foundry moldings are homogeneous in structure and structural integrity.

Abstract: A process for compacting powdery materials is initiated by a pressure surge in which a surge G.sub.1 acts at a time t.sub.1 on the surface of the powdery material and, at the same time, a surge G.sub.2 is applied at a time t.sub.2 to a region of the material at a distance from the surface in the direction of the pattern so that friction between the sides of the mold housing and the compacting material is reduced. The time relationship is such that the air introduced into the material by surge G.sub.2 has time to escape before the surge G.sub.1 reaches the pattern plate. For this purpose, openings 9 are provided in the pattern plate between the mold box wall 3 and pattern 2. These openings can be arranged around the marginal areas of the pattern plate and can vary in size and number depending upon the distance between the wall 3 and pattern 2 or on the shape of the pattern. The openings can be vented to the atmosphere or connected to a suction source.

Abstract: Granular material is selectively compressed in a molding box by a series of pressure surges applied over the granular material.