1. A circuit module having a circuit carrier (12), at least one circuit (14) which is mounted on the circuit carrier (12) and which is surrounded by a protective mass (16), and at least one electricalelectronic component (18) which is surrounded by a protective shell (20) which protects at least the at least one electricalelectronic component (18) from the protective mass (16), characterized in that the protective shell (20) protecting the at least one electricalelectronic component (18) is surrounded by the protective mass (16) only in part.
2. The circuit module as claimed in claim 1, characterized in that the protective shell (20) forms a holding area (22) for holding the at least one component (18) and a flange area (24) for tethering the protective shell (20) to the circuit carrier (12).
3. The circuit module as claimed in claim 1, characterized in that the holding area (52) of the protective shell (20) is in the form of a pot, the open end of which accommodates the flange area (24), which is in the form of a circumferential collar.
4. The circuit module as claimed in claim 1, characterized in that the flange area (24) has at least one sealing device (26).
5. The circuit module as claimed in claim 1, characterized in that the protective shell (20) has a pressure equalization device (30).
6. The circuit module as claimed in claim 1, characterized in that at least one of the protective shell (20) and the protective mass (16) are produced using an injection molding method.
7. The circuit module as claimed in claim 1, characterized in that the protective shell (20) is produced from a plastic.
8. A method for producing a circuit module (10) as claimed in claim 1, having a circuit carrier (12), at least one circuit (14) which is mounted on the circuit carrier (12) and which is surrounded by a protective mass (16), and at least one electricalelectronic component (18) which is surrounded by a protective shell (20) which protects at least the component (18) from the protective mass (16), comprising
mounting the at least one circuit (14) and the at least one electricalelectronic component (18) on the circuit carrier (12),
putting the protective shell (20) which surrounds the at least one electricalelectronic component (18) onto the circuit carrier (12),
pressing the protective shell (20) onto the circuit carrier (12) using a tool, and
putting on the protective mass (16), which surrounds the circuit (14) completely and the protective shell (20) of the electricalelectronic component (18) in part.
9. The method as claimed in claim 8, characterized in that putting on the protective mass (16) involves at least one sealing device (26) fitted to the protective shell (20) being elastically deformed and performing a sealing function.
10. The method as claimed in claim 8, characterized in that putting on the protective mass (16) involves the protective mass (16) being introduced into at least one structure (28) which is provided in the protective shell (20).
11. The circuit module as claimed in claim 1, characterized in that the flange area (24) has at least one structure (28).
12. The circuit module as claimed in claim 11, characterized in that the flange area (24) has at least one sealing device (26).
13. The circuit module as claimed in claim 1, characterized in that the protective shell (20) is produced from a thermoplastic.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Regulation method for an electrolytic cell for the production of aluminum by means of electrolytic reduction of alumina dissolved in an electrolyte bath based on cryolite, said cell comprising a pot, at least one anode, at least one cathode component, said pot comprising internal side walls and being capable of containing a liquid electrolyte bath, said cell comprising at least one means to set said cell including a mobile anode frame to which said at least one anode is attached, said cell being capable of circulating an electrolytic current in said bath, said current having an intensity I, the aluminum produced by means of said reduction forming a liquid metal pad on said cathode component, said cell comprising a solidified bath ridge on said walls,
wherein said regulation method comprises:
determining a value of at least one indicator B by making a measurement of at least one variation of said ridge and wherein said indicator B correlates to said variation, and
adjusting operating parameters to control overall thermics of said electrolytic cell using the value determined for indicator B as a basis for making adjustment to said parameters.
2. Regulation method according to claim 1, wherein said measurement comprises making at least one electrical measurement on said cell to detect variations of the current lines induced by the variation of said ridge.
3. Regulation method according to claim 2, wherein said electrical measurement is conducted by determining an intensity I and of the drop in voltage U at the terminals of said cell.
4. Regulation method according to claim 3, wherein said electrical measurement comprises determining a specific resistance variation \u0394RS by determining at least one first value I1 for said intensity I and at least one first value U1 for the drop in voltage U at the terminals of said cell;
calculating a first resistance Ri from at least said values I1 and U1;
moving the anode frame by a determined distance \u0394H, from an initial position, either upwards, or downwards;
determining at least one second value I2 for said intensity I and at least one second value U2 for the drop in voltage U at the terminals of said cell;
calculating a second resistance R2 from at least said values I2 and U2;
calculating a resistance variation \u0394R using the formula \u0394R=R2\u2212R1;
calculating said specific resistance \u0394RS using the formula \u0394RS =\u0394R\u0394H.
5. Regulation method according to claim 4, wherein the measurement method also comprises, at least after the determination of the values of I1, I2 U1 and U2, moving the anode frame so as to return it to an initial position and restore an initial cell setting.
6. Regulation method according to claim 5, wherein said first and second resistance are calculated using the formula R=(U\u2212Uo)I, where Uo is a constant.
7. Regulation method according to claim 6, wherein the constant Uo is from 1.6 to 2.0 V.
8. Regulation method according to claim 4, wherein said adjusting using said indicator B further comprises calculating the difference between said specific resistance variation \u0394RS and a predetermined reference value \u0394RSo in order to optimize adjustment of said pot functions.
9. Regulation method according to claim 1, wherein said measurement comprises determining the surface area S of said liquid metal pad to define the value of said indicator B.
10. Regulation method according to claim 9, wherein said surface area is determined by:
removing a quantity of liquid metal from the electrolytic cell;
determining the volume Vm of said quantity of liquid metal removed from the electrolytic cell;
determining the change \u0394Hm of the resulting level of said liquid metal pad in said pot;
determining a surface area S for said liquid metal pad using the formula S =Vm\u0394Hm.
11. Regulation method according to claim 10, wherein said volume Vm is determined by measuring the mass of said quantity of liquid metal removed from the electrolytic cell.
12. Regulation method according to claim 9, wherein said adjusting further comprises determining the difference between the value obtained for said surface area S and a set-point value So.
13. Regulation method according to claim 1, wherein said adjusting comprises modifying the position of said mobile anode frame, either upwards, or downwards, so as to modify the anodemetal distance.
14. Regulation method according to claim 1, wherein said adjusting comprises adding solid or liquid electrolyte bath so as to increase the level of said liquid electrolyte bath in said pot.
15. Regulation method according to claim 1, wherein said adjusting comprises modifying said AlF3 addition.
16. A regulation method as claimed in claim 1, wherein said adjusting operating parameters reduces the amplitude and dispersion of fluctuations of said parameters such that the cell has a current efficiency of at least about 93%.
17. A regulation method as claimed in claim 1, wherein said adjusting operating parameters comprises one or more of the following (i) changing the quantity of alumina andor AlF3 being added to said bath, (ii) modifying the position of said mobile anode frame, either upwards, or downwards, so as to modify the anodemetal distance, andor (iii) adding solid or liquid electrolyte bath to said cell.
18. A regulation method as claimed in claim 1, wherein said at least one variation of said ridge comprises a variation in the thickness andor a variation in the shape of said ridge.
19. A regulation method for an electrolytic cell for the production of aluminum by means of electrolytic reduction of alumina dissolved in an electrolyte bath based on cryolite, said cell comprising a pot, at least one anode, at least one cathode component, said pot comprising internal side walls and being capable of containing a liquid electrolyte bath, said cell also comprising at least one means to set said cell including a mobile anode frame to which said at least one anode is attached, said cell being capable of circulating an electrolytic current in said bath, said current having an intensity I, the aluminum produced by said reduction forming a liquid metal pad on the cathode component, said cell comprising a solidified bath ridge on said walls, said method comprising:
setting up a regulation sequence comprising a series of time intervals of pre-determined length Lp;
determining the value of at least one indicator B by measuring at least one variation of said solidified bath ridge such that said indicator B correlates to said variation;
determining a quantity Qo(p), corresponding to the net average AlF3 requirements of the cell;
determining a corrective term Qi(p) including at least one term Qsol(p), which is determined from said indicator B;
determining a quantity Q(p) of AlF3 to be added during the period p, by adding the corrective term Qi(p) to the basic term Qo(p) such that Q(p)=Qo(p)+Qi(p);
adding into said electrolyte bath, during the period p, of an effective quantity of AlF3 equal to said determined quantity Q(p).
20. Regulation method according to claim 19 wherein said length Lp of said periods is approximately the same for all the periods.
21. Regulation method according to claim 19, wherein said length Lp of each of said periods is from 1 to 100 hours.
22. Regulation method according to claim 19, wherein the term Qsol(p) comprises at least one term Qr(p) which is determined from at least one electrical measurement on said cell capable of detecting variations in the current lines induced by the variation of said ridge.
23. Regulation method according to claim 22, wherein the term Qr(p) is determined from at least one measurement of said intensity I and at least one measurement of the drop in voltage U at the terminals of said cell.
24. Regulation method according to claim 23, wherein said method further comprises:
determining at least one first value I1 for said intensity I and at least one first value U1 for the drop in voltage U at the terminals of said cell;
calculating a first resistance R1 from at least said values I1 and U1;
moving the anode frame by a determined distance \u0394H, from an initial position, either upwards, or downwards;
determining at least one second value I2 for said intensity I and at least one second value U2 for the drop in voltage U at the terminals of said cell;
calculating a second resistance R2 from at least said values I2 and U2;
calculating a resistance variation \u0394R using the formula \u0394R =R2\u2212R1;
calculating a specific resistance variation \u0394RS using the formula \u0394RS=\u0394R\u0394H;
determining a term Qr(p) based on said specific resistance variation \u0394RS;
determining a corrective term Qi(p) including at least the term Qr(p) in the ridge term Qsol(p).
25. Regulation method according to claim 24, wherein said method further comprises, at least after the determination of the values of I1, I2 U1 and U2, the movement of the anode frame so as to return it to an initial position and restore an initial cell setting.
26. Regulation method according to claim 24, wherein said first and second resistance are calculated using the formula R=(U\u2212Uo)I, where Uo is a constant.
27. Method according to claim 26, wherein the constant Uo is between 1.6 and 2.0 V.
28. Regulation method according to claim 24, wherein the term Qr(p) is given by the function Qr(p)=Kr\xd7(\u0394RS\u2212\u0394RSo), where Kr is a constant and \u0394RSo is a reference value.
29. Regulation method according to claim 28, wherein Kr is between \u22120.01 and \u221210 kghourn\u03a9mm.
30. Regulation method according to claim 24, wherein the term Qr(p) is limited by a minimum value and by a maximum value.
31. Regulation method according to claim 19, wherein the term Qsol(p) comprises at least one term Qs(p) which is determined from at least one determination of the surface area S(p) of said liquid metal pad.
32. Regulation method according to claim 31, wherein said method further comprises:
removing a quantity of liquid metal from the electrolytic cell;
determining the volume Vm of said quantity of liquid metal removed from the electrolytic cell;
determining the change \u0394Hm of the resulting level of said liquid metal pad in said pot;
determining a surface area S for said liquid metal pad using the formula S=Vm\u0394Hm;
determining a term Qs(p) using a determined function of the surface area S(p) of said liquid metal pad;
determining a corrective term Qi(p) including at least the term Qs(p) in the ridge term Qsol(p).
33. Regulation method according to claim 32, wherein said volume Vm is determined by measuring the mass of said quantity of liquid metal removed from the electrolytic cell.
34. Regulation method according to claim 32, wherein the term Qs(p) is determined from the metal surface area difference between the value obtained for said surface area S and a set-point value So.
35. Regulation method according to claim 32, wherein the term Qs(p) is given by the function Qs(p)=Ks\xd7S(p)\u2212So), where Ks is a constant.
36. Regulation method according to claim 35, wherein Ks is between 0.0001 and 0.1 kghourdm2.
37. Regulation method according to claim 32, wherein the term Qs(p) is limited by a minimum value and by a maximum value.
38. Regulation method according to claim 19, wherein said method further comprises:
determining a mean Qm(p) of the total AlF3 additions per period during the last N periods;
determining a quantity Qint(p), using the following formula: Qint(p)=(1D)\xd7Qm(p)+(1\u22121D)\xd7Qint(p\u22121), where D is a smoothing parameter setting the temporal smoothing horizon;
determining the basic term Qo(p) using the formula Qo(p)=Qint(p).
39. Regulation method according to claim 38, wherein said method further comprises:
determining a compensating term Qc1(p) corresponding to an equivalent quantity of AlF3 contained in the alumina added to the cell during the period p;
modifying the term Qo(p) by subtracting the term Qc1(p) from said term Qo(p) using the formula Qo(p)=Qo(p) Qc1(p).
40. Regulation method according to claim 39, wherein the term Qm(p) is given by the equation:
Qm(p)=<Q(p)>+<Qc1(p)>, where
<Q(p)>=(Q(p\u2212N)+Q(p\u2212N+1)+Q(p\u2212N+2)+ . . . +Q(p\u22121))N,
<Qc1(p)>=(Qc1(p\u2212N)+Qc1(p\u2212N+1)+Qc1(p\u2212N+2) + . . . +Qc1(p\u22121))N,
where N is a constant.
41. Regulation method according to claim 40, wherein N is between 1 and 100.
42. Regulation method according to claim 38, wherein the parameter D is equal to PcLp, where Pc is between 400 and 8000 hours.
43. Method according to claim 38, wherein said method further comprises:
determining a quantity Qtheo corresponding to the total theoretical AlF3 requirements of the cell when regulation is started;
initiating the method by taking Qint(0)=Qtheo.
44. Regulation method according to claim 38, wherein it comprises:
the determination of an additional corrective term Qc2(p) using a function of the difference between Qm(p) and Qint(p);
the addition of the term Qc2(p) in the determination of Qi(p).
45. Regulation method according to claim 44, wherein the term Qc2(p) is given by the formula Qc2(p)=Kc2\xd7(Qm(p)\u2212Qint(p)), where Kc2is a constant.
46. Regulation method according to claim 45, wherein Kc2 is between \u22120.1 and \u22121.
47. Regulation method according to claim 44, wherein the term Qc2(p) is limited by a minimum value and by a maximum value.
48. Regulation method according to claim 19, wherein said method further comprises:
determining a mean temperature T(p) of the electrolyte bath;
determining an additional corrective term Qt(p) using a determined function of the difference between said temperature T(p) and a set-point temperature To;
adding the corrective term Qt(p) in the determination of Qi(p).
49. Regulation method according to claim 48, wherein the term Qt(p) is given by the formula Qt(p)=Kit\xd7(T(p)\u2212To), where Kt is a constant.
50. Regulation method according to claim 49, wherein Kt is between 0.01 and 1 kghour\xb0 C.
51. Regulation method according to claim 48, wherein the term Qt(p) is limited by a minimum value and by a maximum value.
52. Regulation method according to claim 19, wherein said method further comprises:
determining a value corresponding to excess AlF3 E(p);
determining an additional corrective term Qe(p) using a function of the difference between the excess AlF3 measured E(p) and its target value Eo;
adding the corrective term Qe(p) in the determination of Qi(p).
53. Regulation method according to claim 52, wherein the term Qe(p) is given by the formula Qe(p)=Ke\xd7(E(p)\u2212Eo), where Ke is a constant.
54. Regulation method according to claim 53, wherein Ke is between \u22120.05 and \u22125 kghour%AlF3.
55. Regulation method according to claim 52, wherein the term Qe(p) is limited by a minimum value and by a maximum value.
56. Regulation method according to claim 19, wherein the quantity Q(p) comprises an additional term Qea(p) which is given by a function of the anode effect energy AEE.
57. Regulation method according to claim 56, wherein the term Qea(p) is limited by a minimum value and by a maximum value.
58. Regulation method according to claim 19, wherein the quantity Q(p) is limited to a maximum quantity Qmax.
59. Regulation method according to claim 19, wherein, when the determined value of the term Q(p) is negative, a value thereof is taken as equal to zero and no AlF3 is added during the period p.