Sand core making machine method

Abstract

Apparatus and methods for making a sand core in a core box are provided. According to one embodiment, the method includes introducing into a cavity of the core box a sand-binder mixture, the sand-binder mixture being introduced into the cavity through an inlet conduit of the core box. Pressurized air is then introduced into the cavity while a flow rate of the pressurized air is measured in a first air flow path upstream the core box. A control unit automatically alters the degree of opening of an electronically controlled flow regulator located in a second air flow path located downstream an outlet conduit of the core box depending on the measured flow rate to regulate the flow of pressurized air into the cavity of the core box.

Claims

1. A sand core making apparatus comprising: a core box having a cavity in which the sand core is formed, the core box including an inlet conduit and an outlet conduit, the outlet conduit being in fluid communication with the inlet conduit through the cavity; a blowing device configured to deliver a sand-binder mixture into the cavity of the core box through the inlet conduit of the core box; a hardening apparatus configured to introduce pressurized air into the cavity of the core box through the inlet conduit of the core box, the hardening apparatus including a heating unit located in a first air flow path upstream of the inlet conduit of the core box, the heating unit configured to heat the pressurized air before the pressurized air is introduced into the inlet conduit of the core box; a flowmeter configured to measure a flow of the pressurized air in the first air flow path; a second air flow path in fluid communication with the outlet conduit of the core box through which the pressurized air is discharged out of the core box; an electronically operated flow regulator located in the second air flow path, the electronically operated flow regulator configured to directly regulate the flow of the pressurized air passing through the second air flow path and to indirectly regulate the flow of the pressurized air passing through the first air flow path; and a control unit that is configured to receive input signals from the flowmeter indicative of flow values of the pressurized air passing through the flowmeter, the control unit being configured to act on the electronically operated flow regulator to regulate the flow of the pressurized air in the second air flow path depending on the input signals received from the flowmeter.

2. The sand core making apparatus according to claim 1, wherein the electronically operated flow regulator is an electronically controlled proportional flow valve that produces a flow output proportional to an electronic control input from the control unit.

3. The sand core making machine according to claim 2, wherein the control unit is configured to detect an obstruction in the outlet conduit of the core box by comparing a flow value received from the flowmeter with the degree of opening of the electronically controlled flow valve and determining an existence of the obstruction if the flow value received from the flowmeter is less than a specific minimum threshold value for the corresponding degree of opening of the electronically controlled valve.

4. The sand core making machine according to claim 2, wherein the control unit is configured to detect an air leak in the core box by comparing a flow value received from the flowmeter with the degree of opening of the electronically controlled flow valve and determining an existence of the air leak if the flow value received from the flowmeter is greater than a specific maximum threshold value for the corresponding degree of opening of the electronically controlled valve.

5. The sand core making apparatus according to claim 1, wherein the electronically operated flow regulator is an electronically controlled flow valve in which a degree of opening of the electronically controlled flow valve is alterable to produce variable pressurized air flow rates inside the second air flow path in response to electronic control inputs from the control unit.

6. The sand core making apparatus according to claim 5, wherein the control unit comprises a processor and a memory having stored therein one or more optimal flow values associated with the core box, the control unit configured to compare the flow values obtained from the flowmeter with the one or more optimal values stored in the memory and to alter the control input to the electronically controlled flow valve based on the comparison.

7. The sand core making apparatus according to claim 1, wherein the flowmeter is located upstream of the heating unit in the first air flow path.

8. The sand core making apparatus according to claim 1, wherein the second air flow path is defined by an outlet pipe to which the electronically operated flow regulator is attached, the core box being removably coupled to the outlet pipe.

9. The sand core making apparatus according to claim 1, wherein the core box includes first and second outlet conduits that are respectively in fluid communication with first and second outlet pipes located downstream of the first and second outlet conduits, the sand core making apparatus further including a third outlet pipe located downstream of the first and second outlet pipes and in fluid communication with the first and second outlet pipes, the electronically operated flow regulator being located in the third outlet pipe.

10. A method for making a sand core in a core box, the core box having a cavity in which the sand core is formed, an inlet conduit and an outlet conduit, the outlet conduit being in fluid communication with the inlet conduit through the cavity, the method comprising; introducing into the cavity of the core box a sand-binder mixture, the sand-binder mixture being introduced into the cavity through the inlet conduit of the core box; introducing pressurized air into the cavity through the inlet conduit of the core box; measuring a flow rate of the pressurized air in a first air flow path upstream of the inlet conduit of the core box; and through use of a control unit, automatically altering the degree of opening of an electronically controlled flow regulator located in a second air flow path located downstream of the outlet conduit of the core box depending on the measured flow rate to regulate the flow of pressurized air into the cavity of the core box.

11. The method of making a sand core in a core box according to claim 10, further comprising heating the pressurized air prior to introducing the pressurized air into the inlet conduit of the core box.

12. The method of making a sand core in a core box according to claim 10, wherein a flowmeter is used in the measuring of the flow rate of the pressurized air in the first air flow path.

13. The method of making a sand core in a core box according to claim 10, wherein the electronically operated flow regulator is an electronically controlled proportional flow valve that produces a flow output proportional to an electronic control input from the control unit.

14. The method of making a sand core in a core box according to claim 10, wherein the electronically operated flow regulator is an electronically controlled flow valve in which a degree of opening of the electronically controlled flow valve is alterable to produce variable pressurized air flow rates inside the second air flow path in response to electronic control inputs from the control unit.

15. The method of making a sand core in a core box according to claim 10, further comprising detecting an obstruction in the outlet conduit of the core box by comparing the measured flow rate of the pressurized air in a first air flow path with the degree of opening of the electronically controlled flow valve and determining an existence of the obstruction if the flow rate is less than a specific minimum threshold value for the corresponding degree of opening of the electronically controlled valve.

16. The method of making a sand core in a core box according to claim 10, further comprising detecting an air leak in the core box by comparing the measured flow rate of the pressurized air in the first air flow path with the degree of opening of the electronically controlled flow valve and identifying the leak as an anomaly if the measured flow rate of the pressurized gas is greater than a specific maximum threshold value for the corresponding degree of opening of the electronically controlled valve.

17. The method of making a sand core in a core box according to claim 10, wherein during when the sand-binder mixture is introduced into the core box the electronically operated flow regulator is maintained in a maximum open position without regard to the measured flow rate of the pressurized air in the first air flow path.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic depiction of a sand core making machine according to one embodiment.

DETAILED DESCRIPTION

(2) A first aspect relates to a sand core making machine 100 comprising a core box 1 in which at least one core is formed. The core box 1 defines a cavity 1.3 with the shape of the core to be made. The core box is preferably formed by at least one upper implement 1.1 and one lower implement 1.2 demarcating the cavity 1.3 therebetween.

(3) The machine 100 comprises a blowing device (not depicted in the drawings) for introducing a material used for making the core in the core box 1, particularly in the cavity 1.3 defined in the core box 1. Said material comprises a sand-binder mixture. The machine 100 is preferably configured for making sand cores with inorganic processes, such that said mixture comprises an inorganic binder and contaminant gases are not generated during core making.

(4) The core box 1 comprises at least one through inlet forming an inlet conduit 1.1.1 and extending from the outside of the core box 1 to the cavity 1.3, through which said mixture is introduced in the cavity 1.3. The core box 1 preferably comprises a plurality of inlet conduits 1.1.1, and the inlet conduits 1.1.1 are arranged in the upper implement 1.1. Before introducing said mixture in the cavity 1.3, said cavity is full of air that must be discharged to allow said mixture to be housed in said cavity 1.3. To that end, the core box 1 comprises at least one through outlet forming an outlet conduit 1.2.1 and extending from the cavity 1.3 to the outside of the core box 1, through which said air is discharged from the cavity 1.3 as said mixture is being gradually introduced in said cavity 1.3. A filter 1.2.2 is furthermore arranged in the outlet conduit 1.2.1 to prevent said mixture from being discharged therethrough. The core box 1 preferably comprises a plurality of outlet conduits 1.2.1. In the embodiment shown in the drawings, all the outlet conduits 1.2.1 have been depicted in the lower implement 1.2 of the core box 1, but the upper implement 1.1 may also comprise outlet conduits 1.2.1.

(5) The machine 100 further comprises a hardening device 3 suitable for introducing pressurized hot air in the core box 1 for hardening the mixture present in said core box 1 once the required amount of mixture has been introduced in said core box 1. The machine 100 comprises a path for said pressurized air to the core box 1, which can be part of the hardening device 3. The hardening device 3 comprises at least one heating unit 3.1 in said path, upstream of the core box 1, for heating the pressurized air before it reaches said core box 1, said path being configured so that said pressurized air goes through the heating unit 3.1 (or at least through a site in which said air is heated by said heating unit 3.1). The hardening device 3 is furthermore suitable for being connected to an air source 4, preferably to a pressurized air source 4, through which the air used for hardening the mixture present in the core box 1 is supplied. The introduced pressurized air must be discharged from the core box 1 once it absorbs the moisture from the mixture as it passes through said core box 1, and the outlet conduit 1.2.1 of the core box 1 is used to that end.

(6) The machine 100 further comprises a flowmeter 7 for measuring the flow of pressurized air through said path, preferably in real time, said flowmeter 7 is preferably furthermore arranged upstream of the heating unit 3.1, and a flow regulator 6 arranged such that it is configured to be able to regulate said flow depending on said measurement. Therefore, in order to improve hardening process efficiency, and therefore core making efficiency, the machine 100 is configured to be able to have control over the pressurized airflow going through the path through which said pressurized air is delivered to the core box 1, in an easy, simple and cost-effective manner. The flow regulator 6 is preferably an electronically-controlled proportional flow valve, but it may also be a manually-controlled proportional flow valve. In this last case, users themselves regulate airflow by manually acting on the flow regulator 6, depending on the identified measurement of the flowmeter 7. The machine 100 can further comprise a pressure regulator 9 for regulating the pressure at which the air is conducted to the core box 1, which can be, for example, an electrically-controlled proportional pressure valve (although it could also be manually controlled).

(7) In some embodiments, the machine 100 can have a display, for example, to be able to display the measured flow, a user being responsible for acting on the flow regulator 6 for regulating the flow depending on the identified measurement, as described. However, to make this method easier, in other embodiments the machine 100 is configured for performing these tasks automatically. To that end, said machine 100 comprises a control unit 8 which is communicated with the flowmeter 7 for receiving the measurement taken by said flowmeter 7 and with the flow regulator 6 in order to be able to act thereon. The control unit 8 is configured for acting on the flow regulator 6 depending on the measurement obtained by means of the flowmeter 7 to thereby regulate pressurized airflow, as required. The control unit 8 can be any device with data processing and/or computing capacity, such as a microprocessor or a microcontroller, for example. In this case, the flow regulator 6 could be an electronically-controlled valve, preferably an electronically-controlled proportional flow valve. If the machine 100 comprises a pressure regulator 9, the control unit 8 can also be communicated with said pressure regulator 9 for controlling same.

(8) The machine 100 can further comprise a memory (not depicted in the drawings) with flow-related information. The optimal flow value (or values) for the specific core box 1 (or for a plurality of core boxes 1, the target core box 1 being selected in each case) can be stored beforehand in the memory, such that the control unit 8 compares the value measured by the flowmeter 7 with this stored value and acts on the flow regulator 6 for modifying the flow, when appropriate, depending on the result of said comparison. This example of the operation of the memory is non-limiting and other possibilities could be used, such as uploading the information of each core box 1 when the corresponding core box 1 is arranged or will be arranged in the machine 100, for example. The memory may or may not be integrated in the control unit 8 itself.

(9) The core box 1 comprises at least one inlet conduit 1.1.1 communicating the outside of the core box 1 with the cavity 1.3, thereby allowing the entry therethrough of pressurized air to the cavity 1.3. The inlet conduit 1.1.1 is preferably arranged in the upper implement 1.1. The core box 1 preferably comprises a plurality of inlet conduits 1.1.1.

(10) In a preferred embodiment, the machine 100 comprises an outlet pipe 5 in fluid communication with the outlet conduit 1.2.1 for conducting air leaving the core box 1 through said outlet conduit 1.2.1 to where it is required. The flow regulator 6 is preferably arranged in said outlet pipe 5, said flow regulator 6 thereby being configured for directly regulating the airflow going through the outlet pipe 5. The outlet pipe 5 is in fluid communication with the path comprised in the machine 100 for conducting pressurized air to the core box 1 through the core box 1 itself (particularly through the outlet conduit 1.2.1, the cavity 1.3 and the inlet conduit 1.1.1), such that when regulating the airflow through said outlet pipe 5, the airflow through said path is also indirectly regulated. Therefore, by means of regulating the flow regulator 6 arranged in said outlet pipe 5, the airflow delivered to the core box 1 is also regulated, the temperature of said air also being able to be easily controlled in addition to the flow, as described above. If the core box 1 comprises a plurality of outlet conduits 1.2.1, the outlet pipe 5 comprises a conduit per each outlet conduit 1.2.1 and a main conduit in which the flow regulator 6 is arranged connected to the different conduits, although preferably the outlet pipe 5 comprises a single conduit connected with all the outlet conduits 1.2.1.

(11) The outlet pipe 5 is coupled to the core box 1 through a specific coupling which allows quick and simple coupling and uncoupling. In this manner, when one core box 1 is to be replaced with another, for example, the outlet pipe 5 can be uncoupled from the core box 1 comprised in the machine 100 at that moment, and subsequently coupled to the new core box 1 of said machine 100.

(12) The inclusion of an outlet pipe 5 and a flow regulator 6 in said outlet pipe 5 furthermore allows obtaining another series of advantages in the machine 100, in addition to those already described. With this configuration of the machine 100, the control unit 8 can furthermore be configured for identifying an anomaly in the machine 100 during the introduction of pressurized air in the core box 1, depending on the measurement obtained by means of the flowmeter 7 and depending on the degree of opening of the flow regulator 6.

(13) For example, the control unit 8 can be configured for detecting an obstruction in the outlet conduit 1.2.1 depending on how much the flow regulator 6 is regulating the flow (degree of opening/closing of said flow regulator 6) and on the measurement obtained with the flowmeter 7, and for identifying said obstruction, which is at least a partial obstruction, as an anomaly, if the measured flow value is less than a specific minimum threshold value for the corresponding degree of opening/closing of the flow regulator 6. If in order to attain the required flow there is a need to cause a degree of opening/closing in the flow regulator 6 greater than a specific degree, the control unit 8 is capable of identifying this inconsistency and identifying it as an anomaly, furthermore being able to report same. This can be due, for example, to the fact that the outlet conduit 1.2.1 has been completely or partially obstructed by the mixture from the cavity 1.3, and this can thus be reported so that a user acts as they deem necessary (stopping the machine 100 and cleaning the corresponding through inlet or replacing the core box 1, for example) and where appropriate, such that the user only interrupts production when it is actually required. The values at which the control unit 8 can identify an anomaly are previously established in the corresponding operating cycle, and can be stored in the memory described above or in an additional memory. The control unit 8 can also be configured for stopping the machine 100 when it identifies this anomaly.

(14) The control unit 8 can also be configured for detecting an unwanted pressurized air leak in the core box 1 depending on how much the flow regulator 6 is regulating the flow (degree of opening/closing of said flow regulator 6) and on the measurement obtained with the flowmeter 7, and for identifying said leak as an anomaly if the measured flow value is greater than a specific maximum threshold value for the corresponding degree of opening/closing of the flow regulator 6. For example, if an incoherent flow (a high flow) is measured despite the flow being completely or partially closed with the flow regulator 6, this can be a sign that there is a leak through which the pressurized air flows out (and not only through the outlet pipe 5). The control unit 8 can therefore report this anomaly, and the user will act as they deem appropriate. Anomalies negatively affecting core making efficiency can therefore be detected (in this case, excess pressurized air and excess heat output would go to waste), which contributes to improving overall machine efficiency. The control unit 8 can also be configured for stopping the machine 100 when it identifies this anomaly.

(15) The control unit 8 can be configured for detecting the two cases described above, an obstruction and an air leak, as described, respectively.

(16) Therefore, further as a result of the additional capacity for detecting anomalies in the machine 100, like in the case described above, for example, a safer machine 100 is obtained.

(17) In cases in which the machine 100 comprises an outlet pipe 5 and a flow regulator 6 arranged in said outlet pipe 5, the control unit 8 can furthermore be configured for maintaining the highest possible flow through the outlet pipe 5 during the introduction of the mixture in the core box 1, and for regulating said flow by adapting the degree of opening/closing of the flow regulator 6 depending on the measurement thereof during the introduction of pressurized air in the core box 1. Therefore, when blowing the mixture in the core box 1 the air present in said core box 1 is allowed to leave said core box 1 as quick as possible to obtain a process that is as quick as possible, whereas when hardening said mixture present in the core box 1 the maximum flow through the outlet pipe 5 is regulated to obtain more efficient hardening. In this manner, incorporating an outlet pipe 5 and a flow regulator 6 arranged in said outlet pipe 5 for improving hardening efficiency does not negatively affect the blowing process during core making, and therefore does not negatively affect the production of cores in the corresponding machine 100, despite the fact that the air discharged from the core box 1 during blowing and the pressurized air discharged from said core box 1 during hardening share the same discharge path (the outlet conduit 1.2.1 and the outlet pipe 5).

(18) A second aspect relates to a sand core making method in which, in order to make a core, a corresponding sand-binder mixture is introduced in a core box 1 in which cores are made, said mixture being the material used for making said cores, and after introducing said mixture in the core box 1, pressurized hot air is introduced in said core box 1 for hardening said mixture, said pressurized air being conducted to the core box 1 through a specific path. The method is preferably a sand core making method in which, in order to make core, an inorganic sand-binder mixture is introduced, contaminant gases not being generated during core making.

(19) During the introduction of pressurized hot air in the core box 1, the flow of pressurized air through the path through which it is conducted to the core box 1 is measured, and depending on said measurement, said flow is regulated to a desired flow value, the same advantages as those described above for the machine 100 being obtained. Flow measurement and regulation are preferably performed automatically, there being to that end, for example, a control unit 8, a flowmeter 7 and a flow regulator 6 communicated to one another, as described for the first aspect of the invention.

(20) The pressurized air introduced in the core box 1 is conducted to where it is required through an outlet pipe 5 after being discharged from the core box 1 through the outlet conduit 1.2.1, the passage through said outlet pipe 5 being regulated to regulate the flow of pressurized air through the path conducting it to the core box 1. This is possible because said path and said outlet pipe 5 are in fluid communication through the core box 1, as described for the first aspect of the invention, such that regulation in one location also has impact on another location. To regulate the flow of pressurized air, a flow regulator 6 arranged in the outlet pipe 5 is acted on, the degree of opening of said flow regulator 6 being regulated to regulate the maximum flow allowed through the outlet pipe 5.

(21) During the introduction of the mixture in the core box 1, the flow of pressurized air through the outlet pipe 5 is maintained at the highest possible flow regardless of the flow measurement, flow regulation being performed depending on said measurement during the introduction of pressurized air in the core box 1. Therefore, as described above for the machine 100, the process of blowing material in the core box 100 is not negatively affected by the inclusion of the outlet pipe 5 and the pressure regulator 6 for improving hardening process efficiency, despite the fact that the air discharged from the core box 1 during blowing and the pressurized air discharged from said core box 1 during hardening share the same discharge path (the outlet pipe 5).

(22) The proposed method can be implemented in a machine 100 such as the one of the first aspect in any of the embodiments and/or configurations of the machine 100. Similarly, the proposed machine 100 is suitable and/or configured for supporting the method of the second aspect in any of the embodiments and/or configurations of the method.

(23) The following clauses disclose in an unlimited manner additional embodiments.

(24) Clause 1. A sand core making machine comprising a core box (1), a blowing device suitable for introducing a sand-binder mixture in the core box (1), and a hardening device (3) suitable for introducing pressurized hot air in the core box (1), conducted through a specific path to said core box (1), for hardening the mixture present in said core box (1), the hardening device (3) comprising at least one heating unit (3.1) in said path upstream of the core box (1) for heating said pressurized air before it reaches said core box (1), and the machine (100) further comprising a flowmeter (7) for measuring the flow of the pressurized air through said path and a flow regulator (6) for regulating said airflow, the flow regulator (6) being able to be acted on depending on the measurement obtained by the flowmeter (7), the machine (100) further comprises a control unit (8) which is communicated with the flowmeter (7) and with the flow regulator (6), and configured for acting on the flow regulator (6) for regulating pressurized airflow depending on the measurement obtained by means of the flowmeter (7), the core box (1) comprising a cavity (1.3) with the shape of the core to be made, at least one inlet conduit (1.1.1) communicating the outside of the core box (1) with the cavity (1.3) to be able to introduce the mixture and the pressurized air in the cavity (1.3), and at least one outlet conduit (1.2.1) different from the inlet conduit (1.1.1), communicating the outside of the core box (1) with the cavity (1.3) to be able to discharge air present in the cavity (1.3) from said cavity (1.3) as the mixture and the pressurized air are introduced in said cavity (1.3), the machine (100) comprising an outlet pipe (5) in fluid communication with the outlet conduit (1.2.1) for conducting air discharged through said outlet conduit (1.2.1) where required, and the flow regulator (6) being arranged in said outlet pipe (5), said flow regulator (6) thereby being configured for directly regulating the flow through the outlet pipe (5).

(25) Clause 2: The sand core making machine according to clause 1, wherein the control unit (8) is configured for identifying an anomaly in the machine (100) during the introduction of pressurized air in the core box (1), depending on the flow measurement obtained by means of the flowmeter (7) and depending on how much the flow regulator (6) is regulating the flow through the outlet pipe (5), said control unit (8) being configured for detecting at least a partial obstruction of the outlet conduit (1.2.1) depending on the flow measurement obtained by means of the flowmeter (7) and depending on how much the flow regulator (6) is regulating the flow of pressurized air through the path to the core box (1), and for identifying said obstruction as an anomaly if the measured flow value is less than a specific minimum threshold value for the corresponding flow regulated by the flow regulator (6), and/or being configured for detecting an unwanted pressurized air leak in the core box (1) depending on the flow measurement obtained by means of the flowmeter (7) and depending on how much the flow regulator (6) is regulating the flow of pressurized air through the path, and for identifying said leak as an anomaly if the measured flow value is greater than a specific maximum threshold value for the corresponding flow regulated by the flow regulator (6).

(26) Clause 3: The sand core making machine according to clause 1 or 2, wherein the control unit (8) is configured for maintaining the highest possible flow through the outlet pipe (5) during the introduction of the mixture in the core box (1), and for regulating said flow by adapting how much the flow regulator (6) is regulating the flow depending on the measurement of the flowmeter (7) during the introduction of pressurized air in the core box (1).

(27) Clause 4: The sand core making machine according to any of the preceding clauses, wherein the flow regulator (6) is an electronically-controlled proportional flow valve.

(28) Clause 5: A sand core making method, wherein to make a core a sand-binder mixture is introduced in a cavity (103) of a core box (1) through at least one inlet conduit (1.1.1) of the core box (1), after introducing said mixture in the core box (1), pressurized hot air is introduced in said core box (1) for hardening said mixture through said inlet conduit (1.1.1), conducting said pressurized air to the core box (1) through a specific path, and, during the introduction of pressurized hot air in the core box (1), the flow of pressurized air through said path is measured, and, depending on said measurement, said flow is regulated to a desired flow value, characterized in that flow measurement and regulation is performed automatically, the pressurized air introduced in the core box (1) being conducted to where it is required through an outlet pipe (5) and an outlet conduit (1.2.1) that fluidically communicates the cavity (1.3) with the outlet pipe (5), after being discharged from the core box (1), the passage through said outlet pipe (5) being regulated to regulate the flow of pressurized air through the path conducting it to the core box (1), a flow regulator (6) arranged in the outlet pipe (5) being acted on for regulating the pressurized airflow, the degree of opening/closing of said flow regulator (6) being regulated to regulate flow.

(29) Clause 6: The sand core making method according to clause 5, wherein anomalies are detected during the introduction of pressurized air in the core box (1) depending on the obtained flow measurement and depending on how much the flow regulator (6) is regulating the flow through the outlet pipe (5), at least a partial obstruction being detected as an anomaly if the measured flow value is less than a specific minimum threshold value for the corresponding flow regulated by the flow regulator (6), and/or an unwanted pressurized air leak in the core box (1) being detected as an anomaly if the measured flow value is greater than a specific maximum threshold value for the corresponding flow regulated by the flow regulator (6).

(30) Clause 7: The sand core making method according to clause 5 or 6, wherein during the introduction of the mixture in the core box (1), the flow of pressurized air through the outlet pipe (5) is maintained at the highest possible flow regardless of the flow measurement, flow regulation being performed depending on said measurement during the introduction of pressurized air in the core box (1).