Georg Fischer Aktiengesellschaft

Georg Fischer Giessereianlagen Ag

George Fischer Aktiengesellschaft

Georg Fischer Disa Ag

Georg Fischer Aktiengeselleschaft

Kurt Fischer

Hans Leutwiler

Hans Tanner

Robert Steinemann

Georges Louys

Franz Mueller

Ernst O Kruse

Franz Muller

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

An apparatus for producing sand mold employing compressed air comprises a sand molding apparatus for use in making sand molds by employing compressed air. The apparatus includes, in the preferred embodiment, a pattern plate carrier having a top surface for supporting a pattern plate thereon. A molding box is positioned on the top surface of the pattern plate carrier and surrounds the pattern plate so as to define between the pattern plate and the interior surface of the molding box a peripheral area on the top surface of the carrier. Vents are provided on either the peripheral area define above or the pattern plate or both and extend around the pattern plate for allowing compressed air which is injected into the molding box during compression of the molding sand to escape on the pattern side of the molding box. A chamber is defined within the carrier beneath the pattern plate and is communicated with the vent structure by means of bores. The chamber is thereafter communicated with a conduit for removing the compressed air to a remote location.

Molding machine with pattern venting

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

A forming apparatus for the manufacture of casting molds made from sand or another moldable mixture by means of a pressure shock wave from a gaseous medium is proposed. The forming apparatus comprises a structural frame constructed from columns, cross beams, and longitudinal beams, a forming combination within the structural frame, and a pressure vessel for producing the pressure shock wave. The pressure vessel is located above the forming combination and is supported by the cross beams of the structural frame. The forming apparatus also includes a filling vessel containing a supply of sand or other moldable mixture for delivery to the forming combination. The filling vessel is located above the forming combination and is supported by the cross beams of the structural frame is such manner that the topmost edges of these cross beams lie in substantially the same plane as the bottom of the filling vessel. This arrangement results in the center of gravity of the apparatus lying within the range of the forming combination. With such a forming apparatus, the pressure vessel can be exchanged for other pressure vessels of even larger size without incurring major expenses.

Molding apparatus

A molding appartus for use in the production of a casting mold from a granular molding material wherein the space between the pattern and the mold frame is provided with a plurality of orifices such that the sum of the area of the orifices is at least 1% the area of pattern plate between the pattern and the mold frame so as to allow for a flow through rate of air through the orifices of at least 0.005 kg/sec.

Molding equipment for the production of a casting mold

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

Process for selectively compressing granular material in a molding box

An apparatus for the introduction of a gaseous medium into a chamber, especially for compressing casting molding material with a high-pressure gaseous medium supplied by a pressure vessel linked with the chamber by means of a valve system. The system has a seat having traversing openings which can be covered or uncovered by a stroke-activatable valve plate. The gaseous medium flows freely round the surface of the valve plate. The valve plate also is provided with traversing openings which, however, are displaceably arranged vis-a-vis the traversing openings of the valve seat. To trigger a pressure shock from the gaseous medium necessary to effect compression, an elevating mechanism for the valve is activated to lift the valve plate. The pressurized gaseous medium then flows round, as also throughout the valve plate and acts on the surface of the chamber.

Apparatus for the compression of granular material

The apparatus has a plurality of tubular hollow members arranged between the pressure chamber and the molding units, in the pressure surge flow direction, for conducting the gaseous medium to the top of the molding material. With distribution of the pressure medium flow through a plurality of independent and different cross sections, the lifting force required to open the packing element is greatly reduced and the packing element can be opened rapidly.

Apparatus for compacting granular molding materials by pressurized

Loosely poured granular material is compacted by a burst of air under pressure which is built up in a space Q1 and is abruptly released through the outlet end of a passageway Q3 which opens toward the material surface. While the pressure in Q1 is being built up and until released, it is restrained by a sealing member which concurrently covers the outlet side of Q1, the input end of passage Q3 and an accelerating space Q2. The sealing member is held in place by a counterpressure in a space Q4 acting on a larger surface area than Q1. The pressure is suddenly decreased in Q4, abruptly unbalancing the pressures and releasing the pressurized gas from Q1 into Q3 and against the surface.

Method and apparatus for compacting granular moulding materials

An apparatus for compacting granular molding material, particularly foundry molding material, includes a filling unit, a compression unit and a molding unit. A sealing surface on the molding unit is engaged by depending sealing strips on the compression unit to provide a tight seal. The opposed sealing strips extending parallel to molding unit movement have force-transmitting sealing elements, while the other pair of opposed sealing strips extending perpendicular to the molding unit movement repel molding material from the sealing surface.

Apparatus for compacting granular molding materials

In a molding machine for producing foundry sand molds the sand is compressed or packed by means of a pressure wave acting on the sand surface produced by explosive combustion of a mixture of fuel and air. The dosing of the fuel to be burned is carried out by a pressure regulated supply pipe, in which a dosing container is filled with fuel, e.g., gas, up to an exactly defined excess pressure. This fuel or gas is thereafter fed to the combustion chamber under relief of the gas pressure in the dosing container down to a lower pressure level.

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Schaffhausen, Switzerland

Kurt Fischer