Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
  • B22C5/04—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by grinding, blending, mixing, kneading, or stirring
  • B22C5/0409—Blending, mixing, kneading or stirring; Methods therefor
  • B22C5/044—Devices having a vertical stirrer shaft in a fixed receptacle
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/60—Mixing solids with solids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
  • B01F27/05—Stirrers
  • B01F27/07—Stirrers characterised by their mounting on the shaft
  • B01F27/072—Stirrers characterised by their mounting on the shaft characterised by the disposition of the stirrers with respect to the rotating axis
  • B01F27/0724—Stirrers characterised by their mounting on the shaft characterised by the disposition of the stirrers with respect to the rotating axis directly mounted on the rotating axis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
  • B01F27/05—Stirrers
  • B01F27/11—Stirrers characterised by the configuration of the stirrers
  • B01F27/112—Stirrers characterised by the configuration of the stirrers with arms, paddles, vanes or blades
  • B01F27/1121—Stirrers characterised by the configuration of the stirrers with arms, paddles, vanes or blades pin-shaped
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
  • B01F27/23—Mixers with rotary stirring devices in fixed receptacles; Kneaders characterised by the orientation or disposition of the rotor axis
  • B01F27/232—Mixers with rotary stirring devices in fixed receptacles; Kneaders characterised by the orientation or disposition of the rotor axis with two or more rotation axes
  • B01F27/2322—Mixers with rotary stirring devices in fixed receptacles; Kneaders characterised by the orientation or disposition of the rotor axis with two or more rotation axes with parallel axes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
  • B01F27/80—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis
  • B01F27/85—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis with two or more stirrers on separate shafts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F33/00—Other mixers; Mixing plants; Combinations of mixers
  • B01F33/40—Mixers using gas or liquid agitation, e.g. with air supply tubes
  • B01F33/406—Mixers using gas or liquid agitation, e.g. with air supply tubes in receptacles with gas supply only at the bottom
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/40—Mounting or supporting mixing devices or receptacles; Clamping or holding arrangements therefor
  • B01F35/41—Mounting or supporting stirrer shafts or stirrer units on receptacles
  • B01F35/412—Mounting or supporting stirrer shafts or stirrer units on receptacles by supporting both extremities of the shaft
  • B01F35/4121—Mounting or supporting stirrer shafts or stirrer units on receptacles by supporting both extremities of the shaft at the top and at the bottom of the receptacle, e.g. for performing a conical orbital movement about a vertical axis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/71—Feed mechanisms
  • B01F35/714—Feed mechanisms for feeding predetermined amounts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/71—Feed mechanisms
  • B01F35/717—Feed mechanisms characterised by the means for feeding the components to the mixer
  • B01F35/7173—Feed mechanisms characterised by the means for feeding the components to the mixer using gravity, e.g. from a hopper
  • B01F35/71731—Feed mechanisms characterised by the means for feeding the components to the mixer using gravity, e.g. from a hopper using a hopper

Definitions

• binder systems For the production of moulds are used binder systems on organic and inorganic basis. For economic and, especially, environmental reasons it is preferred to use binder system based on an inorganic binder for mould production. However, a certain disadvantage of these binder systems is that they are difficult to reclaim compared to systems with an organic binder system.
• EP 0343272 B1 discloses a process of reclaiming of used foundry sands, where the used foundry sand is in the first stage deprived by heat treatment of all carbon- containing materials, wherein the heat treatment is carried out at temperatures from 500 °C to 900 °C. After the heat treatment, the used sand is transferred into a cylindrical container. In the cylindrical container is rotating a shaft with rods which treats the grains of sand and rubs off the binder from their surface. The disadvantage of this method lies in the necessity of heating the used sand before reclamation and this fact strongly complicates the energetic and economic aspects of the reclamation.
• the newly developed inorganic geopolymer binder systems do not require preheating of the used sand and can be easily reclaimed.
• the reclamation of such used sand with the geopolymer binder is considerably easier.
• the connective envelope can be rubbed without preheating.
• a cylindrical container with a shaft according to the patent EP 0343272 B1 could be used, but the rubbing efficiency is low.
• Loosened grain envelope which is made of an inapplicable cured binding agent has the form of fine dusty particles. These particles have to be immediately removed from the used sand. Otherwise, the electrostatic forces re-attach themselves to the surface and a loss of the reclamation effect occurs. Immediate removal of dust particles from the grain envelope secures an optimal velocity of the air flowing through the fluidized bed between purified particles-grains of sand.
• the increase in efficiency is achieved by the use of a more preferred form of the fluidized bed. While using the previously known cylindrical container with two shafts is the material during a substantial part of the container outside the rubbing effect of bars and reclamation efficiency is therefore low, and there is no effect on the activation of the grain surface.
• the space which is not affected by the action of bars comprises, in this case, 50% of the cross section of the cylindrical container. It can be observed that this often creates the so-called dead space, in which the regeneration of the grains does not occur.
• the reclamation method of foundry sands using a fluidized bed with the shape of a flat oval shows significantly higher efficiency. Contacts between grains and impact bars are more frequent. The grain envelope is removed earlier and by the contact of cleaned grains with bars occurs also an impact, the removal of the envelope from the grain surface and moreover, the sliding of grains along the surface of bars forms the Beilby layer and the surface of the grains activates. Such adapted bed is more efficient because in the case the distance a - 2r, the space that is not directly affected by the bars constitutes only 12% of the cross section of the fluidized bed. This does not create any dead zones without moving of sand grains.
• Another method of improving the efficiency of reclamation of foundry sands is achieved by creating a fluidized bed in the same shape as in the previous case, but with the difference that the distance a of the shafts with impact bars moving in the fluidized bed is less than 2r, as seen in the fig. 2. This allows the overlapping of impact bars and significantly increases the effect of reclamation, wherein the bars arranged on both shafts are located at a different height so that they pass each other during rotation.
• FIG. 3 Another variant of the embodiment of the fluidized bed, resulting in the improvement of the reclamation effect, is the location of the rotating bars in the fluidized bed one above the other.
• the rotating bards placed above each other in a helix.
• the bars move in a fluidized bed with a certain angular rotation.
• the grains are brought in a helical motion and are rubbing easier. It was demonstrated that appropriate rotation angle of the bars is 45 degrees (Fig. 3).
• the buoyancy of grains improves, removal of the grain envelope is more efficient and the engine load reduces.
• the bottom of the fluidized bed is formed by a laminated porous material made by a combination of wire screens, metal powders and metal foils, wherein the pore size is between 0.04 to 0.15 mm. Moreover, such a bottom is highly abrasion resistant and ensures a long durability.
• the equipment for performing the method of reclamation of the used foundry sand with a geopolymer binder is shown in Figs 3, 4 and 5.
• the equipment consists of a casing of the container, which has in a ground plan shape of a flat oval, wherein the bottom 6 of the fluidized bed is arranged in a distance from the bottom of the container.
• the casing ⁇ of the container has in its upper part a dosing opening 8, to which the dosing container 12 is connected.
• the support structure of the carrier 5 for holding its own bottom 6 of the fluidized bed creates a frame in the shape of a flat oval with bearing stiffeners inside surrounding the cylindrical openings for shafts 2.
• the thickness of the bottom 6 of the fluidized bed is 1 ,2 mm.
• the bottom 6 of the fluidized bed preferably consists of a laminated porous material which is a combination of wire screens, metal powder and metal foils, wherein the pore size is 0.060 mm, wherein the porous material is placed in the space between stiffeners.
• Reclamation method is as follows. To the internal space of the container casing 1 is positioned the batch of the sand from the dosing container 12, see Fig. 6. The dosing container 12 is placed on the gauge scales 13, which secures a constant batch size of the used sand. The batch size is chosen so that the volume of impact bars 3 rotating in the fluidized bed comprises 6% of the batch of the used foundry sand, i.e. ratio of the volume of rotating bars 3 to the volume of the batch of the used sand is 0,06.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Casting Devices For Molds (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=51359247

Family Applications (1)

Country Status (3)

Cited By (3)

Citations (2)

Family Cites Families (2)

• 2014
  • 2014-07-03 CZ CZ2014-462A patent/CZ305717B6/cs unknown
  • 2014-07-07 EP EP14752777.4A patent/EP3164234B1/en active Active
  • 2014-07-07 WO PCT/CZ2014/000077 patent/WO2016000665A1/en not_active Ceased

Patent Citations (2)

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