MX2012012332A

MX2012012332A - Method and device by which moulding compound to be processed is kept moist during the production of moulds or cores.

Info

Publication number: MX2012012332A
Application number: MX2012012332A
Authority: MX
Inventors: Rudolf Wintgens; Martin Faller
Original assignee: Laempe & Moessner Gmbh
Priority date: 2010-04-29
Filing date: 2011-04-08
Publication date: 2013-03-05
Also published as: HUE043772T2; EP2563537B2; JP5744183B2; UA109784C2; RU2012146853A; WO2011134598A1; EP2563537B1; ES2600508T5; US20130042989A1; DE102010018751A1; PL3117928T3; EP2563537A1; JP2013525116A; BR112012027621A2; EP3117928B1; AU2011247371A1; EP3117928A1; TR201902510T4; ES2600508T3; AU2011247371B2

Abstract

In order to produce moulds or cores for foundry purposes from a mixture (M) of moulding compound or sand and at least one binder, the mixture is mixed (M) by means of a mixing device (20) and is fed with the aid of a feeding system (30) to at least one sand storage unit (40) of a core or mould production device (50), wherein the mixture-free region (21) of the mixing device (20), at least at times, and/or the feeding system (30) located between the mixing device (20) and the core or mould production device (50), and/or the sand storage unit (40) downstream of the feeding system (30) and upstream of the core or mould production device (50), is moistened or kept moist by means of a liquid (71), wherein the liquid (71) used for moistening is atomised by at least one ultrasonic atomiser (60) to form a suspended aerosol and is fed to the mixing device (20) and/or the feeding system (30) and/or the sand storage unit (40) via pipes (81, 82, 83).

Description

METHOD AND DEVICE BY WHICH THE MOLDEABLE COMPOUND TO BE PROCESSED IS WETTED DURING PRODUCTION OF MOLDS OR MALES Description of the invention The invention relates to a method for producing molds or cores, in particular for casting purposes, wherein the moldable compound or sand and at least one binder that is at least predominantly inorganic, water soluble and / or hygroscopic are mixed by a mixing apparatus, and this mixture being fed to a sand supply unit of a device for the production of cores or molds with the aid of a feeding system.

The invention further relates to a device for producing molds or cores, in particular for casting purposes, with a mixing apparatus for mixing moldable compound or sand and a binder which at least is predominantly inorganic, soluble in water and / or hygroscopic, and with a feeding system for transporting the mixture to a sand supply unit of a core or mold production device.

A method of this type and a comparable device are known by practice and have been accredited.

However it can happen that during the mixing process and also after this the humidity that the Ref No. 236300 binder contains initially lost, so that the mixture dries and crusts in some parts, which on the one hand can hinder the transport and feeding of the mixture to the device of production of cores or molds and for another part fouling the mixing apparatus as well as the downstream feeding system and the sand supply unit. Also the mold making device itself can be clogged due to lumps in the mixture. The consequence can be waste, production stoppage and a high cleaning expense of the whole installation - from the mixing device to the mold production device.

Heretofore these problems are solved by short cleaning intervals, by cooling the mixture or optionally by an increase in the proportion of binder, that is by an additional expense.

For this reason, it is the task to create a method and also a device of the type under consideration, with which a premature drying and formation of lumps of the mixture and the concomitant fouling of the mixing apparatus and / or the feeding system and / or of the sand supply unit.

For the solution of this problem, the method defined at the beginning proposes that the mixing-free region of the mixing apparatus and / or the mixture-free region which lies between the mixing apparatus and the device for producing cores or molds and / or the The mixing-free region of the sand supply unit behind the feeding system and against the production device of cores or molds is kept at least temporarily humid or wet. By means of wetting, a high humidity of air occurs in the mentioned regions, which can counteract or reduce evaporation or loss of moisture in the mixture. Therefore the mixture can not completely or partially solidify or dry or form lumps. That is, it is possible to reduce fouling of the mixing apparatus and / or of the feeding system and / or of the sand supply unit, but also of the device for producing cores and molds and / or to prolong the necessary cleaning intervals. This circumstance can have a particularly positive effect on the productivity of the production process of cores and molds and, in addition, it is possible to extend cleaning intervals and reduce cleaning costs.

It is particularly favorable in this respect that the mixing-free region of the mixing apparatus is wetted or kept moist at least temporarily at least during the mixing process. First of all, due to the mixing process, moisture could come out of the mixture into the mix-free region. By wetting the mixture-free region, it is possible to simply prevent moisture from being lost from the mixture, drying out, depositing in parts of the mixing apparatus and soiling the mixing apparatus.

In addition, it may be advisable to reduce or counteract evaporation or loss of moisture from the mixture, so that above the mixture the humidity of the air is maintained high by feeding moisture, in particular keeping it at approximately 70% to 100%. %, preferably in about 80% to 100%. These air humidity values minimize the moisture gradient between the mixture and the air surrounding the mixture, whereby it is possible to considerably avoid an emission of moisture from the mixture into the air by evaporation, and the concomitant undesired hardening of the mixture.

It is possible that the liquid serving to moisten or the water used for wetting is sprayed by ultrasound to form a suspended aerosol and fed to the mixing apparatus and / or to the feeding system and / or to the sand supply unit. The suspended aerosol comprises such small liquid components that they can evaporate and directly increase the humidity of the air without previously condensing and without depositing as condensate in the mixing apparatus and / or the feeding system and / or the sand supply unit. The size of the liquid particles produced by ultrasound can be found in the order of magnitude of 0.01 mm or below this. Simultaneously, a sufficiently high air humidity is obtained which can prevent the drying of the sand-binder mixture. Both the mixing process as well as the feeding and the preparation of the mixture of sand and binder can be carried out with safety of the process.

The aerosol or the amount of this suspended aerosol and the magnitude of the flow rate provided with the aerosol can be adjusted by modifying the impulse packages emitted by the ultrasound emitter (s) and / or by modifying the voltage of the / the ultrasound emitter (s). In this way it is possible that the quantity of the suspended aerosol with which the mixing apparatus and / or the sand supply unit is wetted is adapted to the existing conditions such as atmospheric humidity, magnitude of the volume to be humidified and room temperature.

A particularly convenient configuration of the method according to the invention may be that the suspended aerosol is formed and fed via one or several lines to the mixing apparatus and / or to the feeding system and / or to the sand supply unit. Accordingly, the production of the aerosol occurs outside of the mixer, feed and / or sand supply unit. That is, for the production of the aerosol, no additional construction space is needed in the mixing, feeding and / or sand supply unit. However, it is possible to provide a sufficiently high air humidity, so that it is possible to avoid drying the sand-binder mixture but without feeding too much liquid, due to which in particular the binder could eventually be washed out or dissolved.

For the solution of the problem, the device defined at the beginning is characterized in that in the mixing apparatus and / or in the feeding system and / or in the sand supply unit there is provided a humidification installation that impinges inside or that empties inside. With the help of the wetting installation it is possible to achieve in a particularly simple way the production and the conservation of the desired air humidity, so that it is possible to reduce the risk of a drying by virtue of moisture loss of the mixture in the apparatus mixer and / or in the feeding system and / or in the sand supply unit. This can favorably reduce fouling of the mixing apparatus and / or of the feeding system and / or of the sand supply unit, but also of the core or mold production device which is disposed downstream.

In this aspect it is possible for the wetting installation to comprise an ultrasonic emitter in the form of an ultrasonic atomizer for water or for a liquid which in particular contains water. That is, the invention also takes advantage of the fact or knowledge that water or a liquid containing water can be sprayed in such a manner with ultrasonic atomizers that the individual droplets can be less than 20 thousandths of a millimeter or even less than 10 thousandths of a millimeter, so that they become moisture in the air and do not deposit or just as a wet film on parts of the mixing apparatus and / or the feeding system and / or the sand supply unit.

It is particularly favorable that the ultrasonic atomizer (s) and an associated liquid reservoir are arranged spatially separate from the mixing apparatus and / or the feeding system and / or the sand supply unit and are communicated with the (s) region (s) that should be wetted by at least one line of pipe or hose. The tests showed that the suspended aerosol formed of water or a liquid containing water by means of an ultrasonic atomizer can be transported without problems for several meters through a line of these to provide sufficiently moist air at the desired site that prevents it from drying the mixture of sand or mouldable compound and binder in particular in the mixing apparatus itself, the feeding system and / or the sand supply unit, but without soaking this mixture too much. The liquid reservoir with the ultrasonic emitter (s) can thus be arranged favorably in a site of the pneumatic machine for making molds or cores, or close to this machine, where there is sufficient room for this purpose .

It is particularly advantageous if the mixing apparatus, the feeding system and the sand supply unit are communicated in each case via a line of pipe or hose with the wetting installation. With pipe or hose lines existing separately for the individual areas of the device it is possible to introduce humid air individually adapted to the individual steps of the process in the mixing apparatus, the feeding system and / or the sand supply unit. Thus, it can be avoided with even greater certainty that the mixture of sand and binder loses moisture in one of the areas mentioned above, dries and dirtifies them.

A refinement of the device according to the invention can propose that the number of the ultrasonic atomizers correspond at least to the number of lines of pipe or hose and at least one ultrasonic atomizer is provided per line of pipe or hose. With at least one ultrasonic atomizer per line of pipe it is possible that even with different values of humidity of the air is sprayed and fed to the respective areas a sufficient quality of liquid in the regions to be wetted, to avoid drying and the formation of lumps in the mixture.

In addition, it may be favorable for the moisture or aerosol of the ultrasonic atomizer (s) to be transported to the mixing apparatus and / or the feeding system and / or the sand supply unit to be disposed in the storage tank. liquid a fan or a compressed gas connection, in particular above the liquid surface. It is true that, above all with relatively short lines, the aerosol could flow into the mixing apparatus and / or the feeding system and / or the sand supply unit by virtue of its own pressure, but nevertheless a fan or a connection of compressed air can improve this flow and also allow a greater distance of the ultrasonic atomizer from the areas of the device that should be supplied with humid air. Additionally, by means of a fan and / or a compressed gas air connection it is possible to overcome height differences between the ultrasonic atomizer and the above areas of the device in the pneumatic machine for making cores. First of all it is possible to transport the aerosol also upwards, so that the ultrasonic atomizer with the liquid reservoir can be disposed below, where there is usually enough room for this. Furthermore, with such an arrangement it is an advantage that a condensate optionally present on the inner walls of the tube or hose in which the aerosol is transported can flow back down to the liquid reservoir.

An alternate embodiment of the invention can propose that the feed system is at least one mobile transport trough. With a mobile transport trough as a feeding system it is also possible to transport the sand-binder mixture of the mixing apparatus to the sand supply unit of the pneumatic machine for making cores or molds over longer distances.

An exemplary embodiment of the invention will now be described in greater detail by means of FIG. 1. FIG. 1 shows, in schematic representation, a longitudinal section of a mixing apparatus, a feeding system and a sand supply unit with a subsequent pneumatic machine for making males or molds as well as a humidification installation with two ultrasonic atomizers and liquid reservoir and with three feeding lines, one of which extends towards the mixing apparatus, one towards the feeding system and one towards the sand supply unit .

A device for the production of molds or cores designated in its entirety with 1, in the embodiment for the production of cores for casting purposes comprises a mixing apparatus 20 with a mixing tool 22 to produce a mixture M by mixing moldable compound or sand and a binder, a feed system 30 for conveying the mixture M to a sand supply unit 40 with a closure device 42 and a device 50 for producing cores or molds.

To moisten the air in the device 1 a humidification installation 2 with two ultrasonic atomizers 60 for water or for a liquid 71 which in particular contains water and with a reservoir 70 of liquid serves. With the help of these ultrasonic atomizers 60 it is possible to spray the liquid 71 to obtain a fine aerosol. This aerosol is indicated in the figure by the two clouds 61 inside the liquid reservoir 60.

A non-represented embodiment of the device can also provide for the provision of three ultrasonic atomizers 60, of which one is associated in each case with one of the three pipe lines 81, 82 and 83, so that for the supply of liquid to the regions to be wetted there is at least one ultrasonic atomizer per line 81, 82 and 83 of pipe. It is thus possible to individually supply and feed the quantity of liquid for the individual areas.

By means of the figure it can also be seen that the humidification installation 2 with the ultrasonic atomizers 60 and the liquid reservoir 70 are arranged spatially separate from the mixing apparatus 20, the feeding system 30 and the sand supply unit 40, but however, they are communicated with the regions that must be wetted by pipe lines 81, 82 and 83, which arrive directly from the liquid tank 70 to the mentioned regions of the device 1 and supply the free regions 21, 31 and 41 therein. mix with moist air. In the exemplary embodiment, not only the mixing apparatus 20, but also the supply system 30 and the sand supply unit 40 have at least temporarily a mixing-free region 31 and 41 in each case.

In the liquid-free region of the liquid container 70, a fan 90 and a compressed gas connection 10 are additionally identified. Either the fan 9 or the compressed gas connection 10 or preferably both serve to transport the aerosol produced by the ultrasonic atomizers 60 via the pipe lines 81, 82 and 83 to the mixing apparatus 20, the feeding system 30 and the 40 unit of sand supply.

Via the pipe lines 81, 82 and 83, sufficient moist air is blown above the mixture M into the mixing apparatus 20, the supply system 30 and the sand supply unit 40, so that the mixture N can hardening or drying in any of the three regions of the device 1, which prevents fouling of the device 1 and thereby improves the free operation of device interruptions and increases the quality of the sand grains produced.

An alternative embodiment of the device 1 not shown in greater detail can propose that the feeding system 30 be at least one transport trough which for example can be moved between the mixing apparatus 20 and the sand supply unit 40 with the help of a track or with a crane. This may be convenient, in particular to overcome greater distances between the mixing apparatus 20 and the sand supply unit 40.

For the production of molds or cores for casting a mixture M of moldable compound or sand and at least one binder, the mixture M is mixed by a mixing apparatus 20 and with the help of a feeding system 30 is fed to the less a sand supply unit 40 of a core or mold producing device 50, whereby the liquid-free region 21 of the mixer apparatus 20 is at least temporarily moistened or kept wet by means of a liquid 71 and / or the system 30 that is between the mixer apparatus 20 and the core or mold production device 50 and / or the sand supply unit 40 downstream of the feed system 30 and upstream of the core or mold production device 50 , wherein the liquid 71 that serves to moisten is sprayed by at least one ultrasonic atomizer 60 to obtain a suspended aerosol and is fed to the mixing apparatus and / or the system. 30 of supply and / or the unit 40 for supplying sand via pipe lines 81, 82 and 83.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. Method for producing molds or cores, in particular for casting purposes, wherein the moldable compound or sand and at least one binder that is at least predominantly inorganic, water soluble and / or hygroscopic are mixed by a mixing apparatus, and being this mixture is fed to a sand supply unit of a core or mold producing device with the aid of a feeding system, characterized in that the mixing-free region of the mixing apparatus is moistened or maintained at least temporarily and / or the mix-free region of the feed system that lies between the mixing apparatus and the core or mold production device and / or the mix-free region of the sand supply unit downstream of the feed system and upstream of the production device of cores or molds.

2. Method according to claim 1, characterized in that the mixing-free region of the mixing apparatus is wetted or kept moist at least temporarily at least during the mixing process.

3. Method according to any of claims 1 or 2, characterized in that an evaporation or moisture exit of the mixture is counteracted by the fact that by means of the supply of moisture above the mixture the humidity of the air remains high, in particular in about 70% to 100%, preferably in about 80% to 100%.

. Method according to any of claims 1 to 3, characterized in that the liquid used to moisten or the water used to moisten is sprayed by ultrasound to obtain a suspended aerosol and is fed to the mixing apparatus and / or the feeding system and / or the sand supply unit.

5. Method according to any of claims 1 to 4, characterized in that the aerosol formed of liquid and the magnitude of the flow rate provided with the aerosol is adjusted by modifying the impulse packages emitted by the ultrasonic emitter (s) and / or by modifying the voltage of the ultrasonic emitter (s).

6. Method according to any of claims 1 to 5, characterized in that the suspended aerosol is formed and fed via one or several lines to the mixing apparatus and / or to the feeding system and / or to the sand supply unit.

7. Device for the production of molds or cores, in particular for casting purposes, with a mixing apparatus for mixing moldable compound or sand and a binder which at least is predominantly inorganic, soluble in water and / or hygroscopic, and with a feed system for transporting the mixture to a sand supply unit of a core or mold producing device, characterized in that a humidification device is provided in the mixing apparatus and / or in the feed system and / or in the sand supply unit. that affects its interior or that flows into its interior.

8. Device according to claim 7, characterized in that the moistening device comprises at least one ultrasound emitter in the form of an ultrasonic atomizer for water or for a liquid which in particular contains water.

9. Device according to any of claims 7 or 8, characterized in that the ultrasonic atomizer (s) and an associated liquid reservoir are arranged spatially separate from the mixing apparatus and / or the feeding system and / or the sand supply unit and communicated (n) by way of at least one line of pipe or hose with the region (s) to be wetted.

10. Device according to any of claims 7 to 9, characterized in that the mixing apparatus, the feeding system and the sand supply unit each communicate with the liquid tank via a line of pipe or hose.

11. Device according to any of claims 7 to 10, characterized in that the number of the ultrasonic atomizers corresponds to at least the number of the lines of pipe or hose, and at least one ultrasonic atomizer is provided per line of pipe or hose.

12. Device according to any of claims 7 to 11, characterized in that to transport the moisture or the aerosol from the ultrasonic atomizer (s) to the mixing apparatus and / or to the feeding system and / or to the supply unit A compressed gas fan or a compressed gas connection is arranged, in particular above the liquid surface in the liquid reservoir.

13. Device according to any of claims 7 to 12, characterized in that the feeding system is at least one mobile transport trough.