Georg Fischer Aktiengesellschaft

Georg Fischer Giessereianlagen Ag

Georg Fischer Disa Ag

Hans Leutwiler

Kurt Fischer

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.

Method for desanding castings

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.

Process for compressing granular material in a molding box

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.

Device for compacting granular molding material

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 &lt;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., and the pressing operation is initiated during the controlled pressure reduction.

Process for the compression of molding sand for casting molds

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.

Molding apparatus including vents comprising elongated slotted bars

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.

Method for compressing granular molding materials

Process for compacting powdery materials

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

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Schaffhausen, Switzerland

Hans Leutwiler