WO2012127303A1

WO2012127303A1 - Barrier for a continuous annealing furnace

Info

Publication number: WO2012127303A1
Application number: PCT/IB2012/000553
Authority: WO
Inventors: Uwe Ziegler; Florian GLÖGGLER
Original assignee: Centrotherm Photovoltaics Ag
Priority date: 2011-03-21
Filing date: 2012-03-21
Publication date: 2012-09-27

Abstract

The invention relates to a barrier and to a continuous annealing furnace comprising a barrier. The barrier (10) comprises at least a frame (36, 37), a actuating element (18), a gate (12), a first lever (14) being pivoted at said frame (36, 37) on a first rotational axis (20) and a second lever (16) being pivoted at said frame (36, 37) on a second rotational axis (21). Said gate (12) and said actuating element (18) are hinged at said first lever (14) opposite said first rotational axis (20) as well as said gate (12). and said actuating element (18) are hinged at said second lever (16) opposite said second rotational axis (21) for moving said gate (12) in a moving direction (68) by actuating said actuating element (18). In accordance with the invention said first and second lever (14, 16) are arranged axially symmetrical in respect to said moving direction (68) at said frame (36, 37). The continuous annealing furnace (26) comprises at least two muffles (28, 30) being connected by an intermediate module (32). Said intermediated module comprises said barrier (10) for isolating a gap (34) constructed in said intermediate module (32).

Description

Barrier for a continuous annealing furnace

The invention relates to a barrier and to a continuous annealing furnace comprising a barrier. Producing solar cells substrates are usually coated with ade^¬ quate materials using continuous annealing furnaces. Such a continuous annealing furnace is regularly segmented in several muffles being arranged in series with said substrates are being transported, i.e. conveyed, there through.

Each muffle of said continuous annealing furnace will be used for operating a defined process step to said substrates while different processing conditions prevailing in each of said muffles operating the process steps.

The muffles are usually equipped with barriers, such as ad^¬ justable gate gas barriers, for providing said defined proc^¬ essing condition localized in a respective muffle while isolating said muffles against each other.

For facilitating a conveying of said substrates along said continuous annealing furnace with passing said barriers arranged intermediate said muffles said barriers had also to be adjustable, i.e. closable and openable.

It is an objective of the invention to provide a barrier and a continuous annealing furnace by which the above-mentioned re^¬ quirements in producing solar cells using barrier-equipped continuous annealing furnaces can be facilitated easily and place-saving as well as reliably. It is a further objective of the present invention to provide a barrier as well as a continuous annealing furnace in which said barrier can be easily constructed and reliably adjustable facilitating high process stability while treating substrates in said continuous annealing furnace, i.e. in said muffles.

These objectives are according to the invention achieved by a barrier and a continuous annealing furnace according to a respective independent claim.

The barrier comprises at least a frame, an actuating element, a gate, a first lever being pivoted at said frame on a first rotational axis and a second lever being pivoted at said frame on a second rotational axis.

Said gate and said actuating element are hinged at said first lever opposite said first rotational axis as well as said gate and said actuating element are hinged at said second lever opposite said second rotational axis for moving said gate in a moving direction by actuating said actuating element.

In accordance with the invention said first and second lever are arranged axially symmetrical in respect to said moving di^¬ rection at said frame (axially symmetrical lever mechanism) .

Easily expressed in other words, the invention provides a bar^¬ rier, especially an adjustable gate gas barrier, comprising a double sided, axially symmetrical lever mechanism operating, i.e. adjusting, said gate by actuating said actuating element. Therefore, the invention provides two levers, being arranged axially symmetrical in respect to said moving direction, espe^¬ cially being mirror inverted to each other, being linked by said shared actuating element as well as by said shared gate. With arranging said first and second lever axially symmetrical in respect of said moving direction and actuating said first and second lever by said shared actuating element the invention achieves a highly constant and accurately guided movementof said gate whereby said barrier could be adjusted, i.e.

opened as well as closed, with high accuracy and reliability.

Hence, the invention realises a high reliability in process isolation for isolated process conditions in muffles being isolated by said barrier.

With using said axially symmetrical arranged levers, especially being mirror inverted to each other, said gate can further be easily constructed as well as said gate can be space- saving arranged in said barrier and actuated accurately.

Therefore, said barrier can be constructed very easily using only few, prefabricated, elementary parts as well as said barrier can be adjusted, i.e. opened as well as closed, with high accuracy and reliability.

The continuous annealing furnace comprises at least two muffles being connected by an intermediate module. Said intermediated module comprises said barrier for isolating a gap constructed in said intermediate module.

Module means any technical unit comprising technical parts which said unit can - easily - be mounted as a whole. Sub^¬ strates treated by said continuous annealing furnace, i.e. by said muffles, can be conveyed from one of said muffle to said other muffle with passing said gap while said gap can be opened or closed by said barrier. Therefore, the barrier - while being closed - will isolate said muffles against each other with isolating a process gas in said muffle and preventing said process gas from flowing in or out of said muffle as well as from flowing from one of said muffle to said other muffle through, i.e. passing, said gap.

Particularly, the invention, i.e. said barrier, especially said adjustable gate gas barrier, will isolate - while closing said gab by said gate - said muffle against a flowing out or flowing in of chalcogen gas/vapours, especially selenium and/or sulphur vapours.

Therefore, damaging condensation by said chalcogen gas/vapours as well as corrosion can effectively be avoided by the inven- tion.

Chalcogen especially will mean selenium and/or sulphur while oxygen is not be meant by chalcogen. Isolating means a basically gas-proof isolation as it can be 95%, preferred 99%, gas-proofed isolated.

Preferred embodiments of the invention will also be subject to dependent claims.

According a preferred embodiment said first and- second lever are being mirror inverted to each other being made of any shape. Preferably, said two levers are of elongated and/or narrow shape.

Said barrier can be an adjustable gate barrier with said gate isolating said gap. In a preferred embodiment said gate is formed like a wall. According to a further preferred embodiment a casing is formed by said frame wherein said gate are movably arranged in said casing being movable in said moving direction. Said casing can comprise sealing elements, e.g. ribs or bars or other embodiments of known gasket seals, like labyrinth- seals or glide seals, for gas-proofing said casing to said gate against process gas flowing in said casing. Gas-proof means basically gas-proof as it will be 95%, preferred 99%, gas-proof.

Therefore, i.e. with sealing said casing against process gas flowing in said casing, damaging condensation on parts of said casing as well as corrosion of said parts by said process gas, especially by said chalcogen vapours, can effectively be avoided.

According to a further preferred embodiment said levers, especially being mirror inverted to each other, are pivoted at said frame, especially inside said casing, by using supporting means, e.g. bearing journals or bolts, being arranged at said frame, especially inside said casing.

Preferably, said actuating element comprises a coupling compo- nent with said levers are being linked or hinged with said coupling component, especially using journals or bolts with said journals or bolts being arranged at said coupling compo^¬ nent . Said connecting element can be formed integrally with said actuating element as well as said connecting element can be a separate part being fixed with said actuating element. Said coupling component can be arranged at an end of said ac^¬ tuating element.

Said actuating element and/or said coupling component can be made of stainless steel.

According to a preferred embodiment said coupling component comprises two journals or bolts being arranged at said cou^¬ pling component opposite each other.

According to a further preferred embodiment an insulator, especially made of ceramic and/or formed like ring, is arranged at said actuating element. Especially, said ceramic insulator can be located between, i.e. intermediate, said actuating ele- ment and said coupling component.

An actuator can be linked to said actuating element actuating said actuating element. According to a preferred embodiment said actuator can be linked at said actuating element opposite said coupling component.

According to an other preferred embodiment said gate and/or said levers as well as other parts of said barrier can be made of carbonate based materials, e.g. of any graphite structure or carbonate based fibre composite materials.

These carbonate based materials are known as being resistant against corrosion, especially against being corroded by said process gas, further more especially corroded by said chalco- gen vapours.

An enhanced isolation of said muffles can be realised by flushing an inside of said barrier, especially flushing said casing, by a flushing gas, e.g. nitrogen gas. An inlet, e.g. a tube, can be arranged at said frame, espe^¬ cially at said casing, for flowing in said flushing gas said casing. ¹

As well as an outlet, e.g. a tube, can be arranged at said frame, especially said casing, for flowing out a mixture of said process gas and flushing gas of said casing. In a preferred embodiment said (inlet-) tube and/or said (out^¬ let-) tube extend - from outside said casing - into said cas^¬ ing.

According to an other preferred embodiment said barrier com- prises at least one sensor for detecting an opening status of said gate.

This at least one sensor can be a motion sensor, a position detecting sensor, a tactile sensor, a fill level detecting sensor, a pressure sensor, an optical sensor, a capacitive sensor or a passage sensor.

According to a preferred embodiment said barrier comprises at least one optical sensor based on a light barrier detecting said opening status of said gate.

Said sensor can be integrated in said tube. Integrated means said sensor to be integrally formed with said tube or being a separate part being arranged in or at said tube as well as said sensor can be said tube itself.

Being equipped with such a „multi-functional" tube - as serv^¬ ing as said sensor as well as said flushing means - said bar- rier can be constructed in a very space- and part-saving manner .

According to a preferred embodiment said barrier is used in a segmented continuous annealing furnace for producing I-III-VI- compound semiconductors, especially for coating substrates that can be used for solar cells, especially for CIGS solar cells. According to a further preferred embodiment said barrier is used for isolating two muffles of said segmented continuous annealing furnace with said segmented continuous annealing furnace operating at temperature exceeding 600°C. Materials being resistant and/or operable at these temperatures are known by person skilled and will be chosen accordingly such temperature-requirements.

According to an other preferred embodiment said barrier is being heatable, e.g. using common heating means, for anticipat- ing condensations of its parts by said process gas, especially by said chalcogen vapours.

Description of preferred embodiments of the invention as far as given specifies numerously features which are grouped in dependent claims in combinations. Person skilled in the art will understand these feature to be used in single as well as person skilled in the art will group these features in other technically worthwhile combinations. With reference to the appended drawings, below follow specific descriptions of embodiments of the invention respectively cited as "segmented continuous annealing furnace with an adjustable gate gas barrier actuating by a two-side, axially symmetric lever mechanism". Identically elements shown in the drawings are referenced by identically references. Further advantages as well as advanta^¬ geous features of the invention will also appear from the following description.

In the drawings:

Figure 1 shows a segmented continuous annealing furnace comprising two muffles and an intermediate module with an adjustable gate gas barrier according to an embodiment of the invention,

Figure 2 shows a ( 3-dimentional ) sectional drawing along

line II-II of figure 1 through said intermediate module with said adjustable gate gas barrier in its closed status,

Figure 3 shows said adjustable gate gas barrier of figure 2 in said closed status and

Figure 4 shows an adjustable gate gas barrier according to a further embodiment of the invention in its open status .

Segmented continuous annealing furnace with an adjustable gate gas barrier actuating by a two/double-sided, axially symmetric lever mechanism (Figures 1 - 4)

Figure 1 shows a segmented continuous annealing furnace 26 with two muffles 28, 30 arranged in series. Said segmented continuous annealing furnace 26 comprising said two muffles 28, 30 will be used for producing I-I I I -Vl-compound semicon- ductors and especially for coating substrates which will be used for CIGS solar cells.

An intermediate module 32 is arranged intermediate said muf- fles 28, 30 with an adjustable gate gas barrier 10 being arranged in said intermediate module 32.

Said adjustable gate gas barrier 10 is mounted, i.e. inserted, in said intermediate module 32 in that way, so as to be assem- bled and/or constructed from above into said intermediate module 32 for constructing tasks and/or maintenance.

Figure 2 shows a sectional drawing along line II-II of figure 1 through said intermediate module 32 with said adjustable ga- te gas barrier 10 in its closed status for isolating said two muffles 28, 30, i.e. for isolating a process gas flowing through a gap 34 arranged in said intermediate module 32 from one of said muffle 28 to said other muffle 30. With said segmented continuous annealing furnace 26 operating at temperature exceeding 600°C said adjustable gate gas bar^¬ rier 10 is designed for reliably working at said temperatures.

Said adjustable gate gas barrier 10 comprises an adjustable gate 12 being actuated by a two-side, axially symmetric lever mechanism 11 with being movable in a moving direction 68.

Said adjustable gate gas barrier 10 comprises said gate 12, a first and a second, elongated lever 14, 16 being assembled as said two/double-side, axially symmetric lever mechanism 11, a lifting element 18 and a T-shaped frame 36.

Said T-shaped frame 36 comprises an asymmetric basic element 37 with a long flank 42 and a short flank being perpendicular to said long flank 42 as well as a counter piece 38 screwed to said basic element 37 forming said -symmetric - T-shaped frame

36 (figures 2 and figures 3) . Said counter piece 38 is screwed to said basic element 37 using several fastenings 40, e.g. bolts, with said fastenings 40 are being screwed to said long flank 42 of said basic element

37. Said short flank 44 of said basic element 37 extends in an axial direction 46 being perpendicular to a moving direction 48 of substrates - not shown - which are treated by said segmented continuous annealing furnace 26, i.e. said muffles 28, 30 arranged in series, as well as being perpendicular to said moving direction 68 of said gate 12. Said long flank 42 is in line with said moving direction 48 of said gate 12.

Said long flank 42 of said basic element 37, a portion 50 of said short flank 44 of said basic element 37 and said counter piece 38 will form - being assembled - a casing 52 with said gate 12 and said lever mechanism 11, i.e. said levers 14, 16, ^■ being assembled inside said casing 52.

Said casing 52 comprises sealing elements 54, i.e. bars 54, formed integrally with said long flank 42 and said counter piece 38 for gas-proofing said casing 52 to said gate 12 against process gas flowing in said casing 52. Gas-proof means basically gas-proof as it will be 95%, preferred 99%, gasproof .

Therefore, i.e. with sealing said casing 52 against process gas flowing in said casing 52, damaging condensation on parts of said casing 52 and parts being assembled inside said casing 52, especially said levers 14, 16, as well as corrosion of said parts by said process gas can effectively be avoided.

Figure _.3 shows said adjustable gate gas barrier 10 before said counter piece 38 is screwed with said basic element 37 forming said casing 52 and before said adjustable gate gas barrier 10 is being mounted in said intermediate module 32 with said adjustable gate gas barrier 10 being in a status in which said gap 34 would be closed while being assembled.

Said short flank 44 of said basic element 37 comprises a bore 56 being centred in said short flank 44 - relatively to an axial dimension of said short flank 44 extending in said axial direction 46 as well as a dimension of said short flank 44 ex- tending in said moving direction 48 - with said lifting element 18 extending through said bore 56 from outside said casing 52 to inside said casing 52.

A coupling component 58, i.e. a splice plate 58, is integrally formed at said lifting element 18 at an end 67 of said lifting element 18 extending inside said casing 52.

Said lifting element 18 as well as said coupling element 58 is made of stainless steel. Said levers 14, 16 are being made of graphite.

Said lifting element 18 is linked with an actuator (not shown) at an end 63 opposite said end 67 with said actuator actuating said lifting element 18 in said moving direction 68.

Two bolts 60 are formed integrally - opposite each other relatively said axial direction 48 - with said coupling component 58. Said first and second lever 14, 16 - being mirror inverted to each other and being , axial ly symmetric arranged relatively to said moving direction 68 - are linked, i.e. hinged_/ at said bolts 60 at centres 24 arranged at ends 62 of said respective lever 14, 16.

Therefore, a motion of said lifting element 18 - in said mov- ing direction 68 (of said lifting element 18) - could be modified to said levers 14, 16.

Said first lever 14 is pivoted on journal 64 with said journal 64 being arranged at said basic element 37 of said frame 36 while said first lever 14 is being rotatable on a first rotational axis 20; said second lever 16 is pivoted on journal 65 with said journal 65 being arranged at said basic element 37 of said frame 36 while said second lever 16 is being rotatable on a first rotational axis 21. Said journals 64, 65 are axi- ally symmetrically arranged relatively to said moving direction 68 of said lifting element 18.

At centres 22 - arranged at ends 66 of said respective lever 14, 16 opposite said centres 62, i.e. said ends 62, relatively said rotational axis 20, 21 - said levers 14, 16 are linked, i.e. hinged, to said gate 12 using bolts 60 formed integrally at said gate 12.

Said centres 24 as well as said ends 62 will stay above said journals 64, 65 in relation to said moving direction 68 while said gate 12 being in said closed status; said centres 22 as well as said ends 66 will stay below said journals 64, 65 relatively said moving direction while said gate 12 being in said closed status. With said journals 64, 65 being arranged at said basic element 37 of said frame 36 (inside said casing 52) said gate 12 com^¬ prises recesses 70 with said journals 64, 65 extending through said recesses 70.

Said gate 12 further comprises a recess 72 centred - relatively to said axial direction 46 - in said gate 12 with said end 76 of said lifting element 18, i.e. said coupling component 58, extending into said recess 72.

Said gate 12 is formed like a wall being made of graphite, extending in said axial direction 46 along an axial dimension of said casing 52 while being assembled in said casing 52, i.e. in said frame 36.

With arranging said mirror inverted first and second lever 14, 16 axially symmetrical in respect of said moving direction 68 and actuating said mirror inverted first and second lever 14, 16 by said shared actuating element 18, i.e. said lifting ele- ment 18, a highly constant and accurately guided movement of said gate 12 can be achieved.

While actuating said lifting element 18, e.g. downward in said moving direction 68, said coupling component 58 will move downward accordingly with guiding said centres 24, i.e. said ends 62, of said first and second lever 14, 16 - hinged at said coupling component 58 by said bolts 60 - downwardly at a same distance in said recess 72 in accordance with said movement of said lifting element 18, i.e. said coupling component 58.

Said first and second lever 14, 16 will counter rotate to each other at a same angle of rotation, - following said movement - with said centres 22, i.e. said ends 66, of said levers 14, 16 moving upward at a same distance.

Said gate 12 will be guided - with being hinged at said mirror inverted and axially symmetric levers 14, 16, i.e. at said ends 66 of said levers 14, 16, by said bolts 60 - upward by said levers 14, 16 while moving highly constant and accu^¬ rately. Hence, said gate 12 can be adjusted, i.e. opened as well as closed, by actuating said lifting element 18 in said moving direction 68 with said actuating movement will be transmitted from said actuating movement of said lifting element 18 to said adjusting movement of said gate 12.

While guiding said gate 12 axially symmetrical by said axially symmetrical levers 14, 16 said adjustable gate gas barrier 10 will be adjusted with said high accuracy and reliability. Figure 4 shows an alternative adjustable gate gas barrier 10 in its open status with said centres 24, i.e. said ends 62, of said levers 14, 16 staying below said journals 64, 65 and said ends 66 relatively said moving direction 68. A ceramic insulator 74 is arranged intermediate said lifting element 18 and said coupling component 58 for insulating said lifting element 18.

Figure 3 shows an inlet tube 76 and an outlet tube 78 being arranged at an upper side 77 of said adjustable gate gas barrier 10, i.e. at said frame 36, for flushing said adjustable gate gas barrier 10 by a nitrogen gas realising an enhanced isolation of said muffles 28, 30. Said inlet tube 76 and said outlet tube 78 are being located opposite each other in said axial direction 46 at said upper side 77 of said basic element 37 with extending - through bores 56 in said frame 36 - into said casing 52.

' . ·

Said nitrogen gas will enter said frame 36, i.e. said casing 52, by said inlet tube 76 flushing said casing 52 while a mixture of said process gas, e.g. chalcogen vapours, and said nitrogen gas will exit said frame 36, i.e. said casing 52, by said outlet tube 78.

Therefore, flushing said adjustable gate gas barrier 10 by said nitrogen gas said chalcogen vapours - intruded in said casing 52 - can be removed from said casing 52 with damaging condensation on parts of said casing 52 and parts being assembled inside said casing 52 as well as corrosion of said parts can effectively be avoided as well.

Two optical sensors 82 based on a light barrier are arranged at said inlet and outlet tube 76, 78 for detecting said - opening or closing - status of said gate 12.

All parts of said adjustable gate gas barrier 10 - other than said lifting element 18, said coupling component 58 as well as said insulator 74 - are made of graphite.

Figures 4 shows an alternative embodiment of said adjustable gate gas barrier 10 - basically identically to said adjustable gate gas barrier 10 shown in Figures 2 and 3 - refraining from said flushing system, i.e. said inlet and said outlet tube 76, 78 for flushing said casing 52.

Said alternative adjustable gate gas barrier 10 is shown in its open status. Although a description of specific embodiments has been pre sented, it is understood that various changes could be made without deviating from the scope of the present invention.

List of References

10 barrier

11 axially symmetric lever mechanism 12 gate

14 (first) lever

16 (second) lever

18 actuating/lifting element

20 first rotational axis

21 second rotational axis

22 centre

24 centre

26 continuous annealing furnace

28 muffle

30 muffle

32 intermediate module

34 gap

36 frame

37 basic element

38 counter piece

40 fastening, bolt

42 long flank

44 short flank

46 axial direction

48 moving direction

50 portion

52 casing

54 sealing element, bar

56 bore

58 coupling component, splice plate

60 bolt

62 end

63 end

64 journal j ournal

end

moving direction (of 12/18) recess

recess

insulator

inlet (tube)

upper side

outlet (tube)

tube

sensor

Claims

Barrier (10) comprising at least a frame (36, 37), a gate (12), a first lever (14) being pivoted at said frame (36, 37) on a first rotational axis (20) and a second lever (16) being pivoted at said frame (36, 37) on a second rotational axis (21) and a actuating element (18),

- wherein said gate (12) and said actuating element (18) are hinged at said first lever (14) opposite said first rotational axis (20) and wherein said gate (12) and said actuating element (18) are hinged at said second lever (16) opposite said second rotational axis (21) for moving said gate (12) in a moving direction (68) by actuating said actuating element (18), and

- wherein said first and second lever (14, 16) are ar^¬ ranged axially symmetrical in respect to said moving direction (68) at said frame (36, 37).

Barrier (10) according to any preceding claim,

wherein said first and second lever (14, 16) are being mi rror inverted to each other.

Barrier (10) according to any preceding claim,

with a casing (52) formed by said frame, (36, 37) wherein said gate (12) are movably arranged in said casing (52) being movable in said moving direction (68).

Barrier (10) according to the preceding claim,

wherein said casing (52) comprises sealing elements (54) for gas-proofing said casing (52) to said gate (12). Barrier (10) according to claim 3 or claim 4,

comprising an inlet (76) and/or an outlet (78) for flushing said casing (52) by a flushing gas.

Barrier (10) according to any preceding claim,

wherein said actuating element (18) is made of stainless steel .

Barrier (10) according to any preceding claim,

wherein said gate (12) and/or said levers (14, 16) are/is made of carbonate based materials/a carbonate based material.

Barrier (10) according to any preceding claim,

with an ceramic insulator (74) arranged at said actuating element (18).

Barrier (10) according to any preceding claim,

with at least one sensor (82) detecting an opening status of said gate ( 12 ) .

Barrier (10) according to the preceding claim,

wherein said at least one sensor (82) is a motion sensor, a position detecting sensor, a tactile sensor, a fill level detecting sensor, a pressure sensor, an optical sen^¬ sor, a capacitive sensor or a passage sensor.

Barrier (10) according to claim 5 and claim 9,

wherein said at least one sensor (82) is integrated in said inlet (76) or said outlet (78).

Continuous annealing furnace (26) comprising at least two muffles (28, 30) being connected by an intermediate module (32) wherein said intermediated module comprises said bar- rier (10) according to any preceding claim. for isolating gap (34) constructed in said intermediate module (32).

Continuous annealing furnace (26) according to the preced ing claim used for coating a substrate for a solar cell.