EP3884169B1 - High-pressure centrifugal ventilator comprising a seal assembly arranged in an inlet - Google Patents

Description

The invention relates to a high-pressure radial fan for the pressure-increasing delivery of a compressible fluid, with a volute housing that has an inlet opening extending through a housing wall for the inlet of the fluid and an outlet opening for the outlet of the fluid, and with an impeller that is arranged in the volute housing so that it can rotate about an axial axis of rotation and has blading formed from a plurality of moving blades, with the blading in a rotating state of the impeller causing the fluid to be sucked in axially through the inlet opening and radially and/or tangentially deflected outflow of the fluid through the outlet opening and thus a pressure-increasing delivery of the fluid from one Causes suction side to a pressure side, and with a formed between the volute and the impeller sealing arrangement, which is provided to minimize a pressure loss between the pressure side and the suction side.

Centrifugal fans are well known and are commonly used to convey compressible fluids. Typical applications of such centrifugal fans can be found in air conditioning, chemical or incineration plants, as well as in the cement, paper or glass industries. In addition to air, erosive, corrosive, explosive, toxic or dusty gases can also be used as the compressible medium. If the pressure increase of the fluid achieved during delivery exceeds a pressure increase ratio of 1.1, the term high-pressure centrifugal fans is usually used.

A well-known high-pressure centrifugal fan has a volute housing with an inlet opening extending through a housing wall and an outlet opening. An impeller is arranged in the volute housing such that it can rotate about an axial axis of rotation and is provided with blading formed from a plurality of impeller blades. When the impeller is rotating, the blading sucks in the fluid to be conveyed axially and flows it in a radially and/or tangentially deflected direction through the outlet opening, causing the fluid to be conveyed from a suction side to a pressure side with increasing pressure. In order to avoid pressure losses as a result of an undesired pressure equalization between the pressure side and the suction side, the known high-pressure centrifugal fan has a sealing arrangement formed between the volute housing and the impeller. In the known high-pressure centrifugal fan, the sealing arrangement is designed in the form of a non-contact labyrinth seal between an axially oriented end face of the impeller and a wall of the spiral housing lying in the interior of the spiral housing.

From the DE 322560 A1 a two-stage fan with a housing and a sealing arrangement is known, the impeller of which has a cover disk and an inlet ring. The sealing arrangement is arranged inside the housing.

From the US 2013/0142641 A1 a labyrinth seal is known which is arranged inside a turbine housing.

From the JP 2011 157829 A a blower for a vacuum cleaner is known, the suction side of which has a sealing arrangement. The sealing arrangement is integrated into a housing and interacts with a sealing surface of the impeller.

From the CN 103511321A a pump for pumping liquids is known. In order to prevent the pressurized liquid from flowing back from the outlet of the pump housing to the inlet in a gap between the impeller and the pump housing, a sealing arrangement is provided inside the housing.

From the U.S. 6,164,909 (D5) a fan is known in which the sealing between the housing and an impeller takes place with the help of an air guide ring (EGR) and also without contact.

From the JP 2008 064066 A a fan for a vacuum cleaner is known.

The object of the invention is to create a high-pressure radial fan of the type mentioned at the outset, which has a simple structure that can be produced inexpensively and at the same time enables the pressure loss between the pressure side and the suction side to be minimized.

This object is achieved by a high-pressure centrifugal fan according to claim 1. Advantageous embodiments of the invention are specified in the subclaims. The sealing arrangement has a contact sealing arrangement arranged in the area of the inlet opening, which seals an annular gap formed between a boundary of the inlet opening and the impeller and which has a sealing surface arranged on the impeller and at least one sealing element contacting the sealing surface, the sealing element being on an outside of the housing wall is releasably attached. The solution according to the invention reliably seals the annular gap formed in the area of the inlet opening between the impeller and the volute housing using simple means. This counteracts a gap loss and a resulting pressure loss and thus an undesirable pressure equalization from the pressure side to the suction side. The solution according to the invention makes it possible, in particular, to dispense with a labyrinth seal between the impeller and the spiral housing, which is complex to manufacture and requires comparatively narrow manufacturing tolerances. Since the sealing element of the contact sealing arrangement is detachably attached to the outside of the housing wall, there are particular advantages in the manufacture, maintenance and/or repair of the high-pressure radial fan. This is particularly the case in relation to labyrinth seals between the impeller and volute casing known in the prior art, which are arranged inside the volute casing and are usually only accessible for maintenance and/or repair purposes after the impeller has been dismantled from the volute casing. In contrast, the sealing element is easily accessible from the outside due to the detachable fastening on the outside of the housing wall, which significantly facilitates manufacture, maintenance and/or repairs. In addition, the inventive arrangement of the sealing element on the outside of the housing wall enables a reduced overall width or depth of the volute housing. In this way, in particular, a particularly streamlined design of the flow-effective cross sections of the volute housing is made possible. The volute housing has a spiral shape of the flow-effective cross-sections that is known in principle in the field of radial fans and is preferably manufactured in the form of a sheet metal construction that can be produced easily and inexpensively with several sheet metal parts joined together. In this case, the inlet opening extends through the housing wall of the volute housing. The inlet opening upstream in the flow direction of the fluid is an intake manifold with a corresponding intake port arranged on the volute. The impeller is designed with a cover disk that covers the blading axially on the front side. A version of the impeller with a cover disk can also be a closed design are referred to and is present according to the invention. An embodiment of the impeller without a cover disc can also be referred to as an open design, but is not part of the present invention. The moving blades can extend radially straight or—with respect to an intended circumferential direction of rotation of the impeller—can be inclined forwards or backwards or be correspondingly curved. With regard to the pressure increase to be achieved, rotating blades curved backwards, curved at the radial end and/or curved forwards have proven to be particularly advantageous in high-pressure centrifugal fans. The contact seal arrangement counteracts undesirable gap losses between the pressure and the suction side and thus serves to minimize the pressure loss between the outlet and the inlet opening of the volute. The inlet opening is assigned to the suction side of the high-pressure centrifugal fan. The outlet opening is assigned to the pressure side of the high-pressure centrifugal fan. The sealing surface of the contact seal arrangement is arranged on the impeller and therefore rotates about the axial axis of rotation during operation. In contrast, the at least one sealing element is releasably attached to the housing and is therefore fixed in relation to the axis of rotation. The at least one sealing element is releasably attached at least indirectly to the outside of the spiral housing. During operation, a relative rotational movement thus occurs between the sealing surface and the at least one sealing element. The sealing surface is preferably in the form of a circular ring, with a normal direction of the sealing surface preferably being oriented radially outwards. The at least one sealing element is preferably designed in the shape of a circular ring. The contact seal arrangement can be designed in particular in the form of a stuffing box, a radial shaft seal, a mechanical seal, a brush seal, a shaft lip seal or the like. Accordingly, the at least one sealing element can be designed, for example, in the form of a radial shaft sealing ring, a brush element, a lip sealing ring or the like.

According to the invention, the impeller has a cover disk, by means of which the blading is covered axially on the front side, the sealing surface being arranged on an inlet ring assigned to the cover disk, which protrudes axially through the inlet opening towards the outside and borders an inlet opening of the impeller. Accordingly, the impeller has the said closed design. In this respect, the cover disc serves in particular to improve the pressure increase when conveying the compressible fluid. The cover disk has a circular ring-shaped basic shape and covers the rotor blades axially at the front at least in sections. The inlet ring bordering the inlet opening can, as a functional section of the cover plate, be in one piece with the rest Be formed sections of the cover plate. Alternatively, the inlet ring as a separate

Component manufactured and then assembled with the cover plate. The inlet ring, the cover disk and the inlet opening are preferably oriented coaxially with one another. The inlet ring preferably acts as a nozzle and brings about a streamlined flow of the blading through the inlet opening. The sealing surface is preferably arranged on a radially outer lateral surface of the inlet ring. Starting from an inside of the volute, the inlet ring protrudes in the direction of the outside through the inlet opening of the volute. This results in the formation of an annular gap between the housing wall of the spiral housing and the inlet ring. The contact sealing arrangement serves to seal this annular gap.

According to the invention, the contact sealing arrangement has a sealing housing which is arranged on the outside of the housing wall and has an installation space in which the at least one sealing element is accommodated. The sealing housing is used to accommodate the at least one sealing element and enables an even more simplified design of the high-pressure centrifugal fan. This is because a separate design of the installation space for accommodating the at least one sealing element directly in the housing wall of the volute housing can be dispensed with. Instead, the installation space is formed on the seal housing. The seal housing is detachably or non-detachably attached to the outside of the housing wall. The seal housing preferably has an annular basic shape and is oriented coaxially to the inlet opening and/or the impeller and/or the inlet opening. The seal housing can have a cover, by means of which the installation space is releasably closed. As a result, assembly and/or disassembly of the at least one sealing element can be simplified even further and thus particularly simple manufacture, maintenance and/or servicing can be achieved.

In a further embodiment of the invention, the seal housing is detachably flanged to the outside of the housing wall by means of a plurality of fastening elements. This is a particularly preferred embodiment of the invention. In particular, screws and/or nuts can be provided as fastening elements. The seal housing and the outside of the housing wall can have flange surfaces which are complementary to one another.

According to the invention, the volute housing has a suction connection opening into the inlet opening, which extends radially and axially over the seal housing. Of the The suction nozzle is used to introduce the compressible fluid to be pumped in a streamlined manner through the inlet opening and/or the inlet opening and can be designed, for example, in the form of a nozzle. Since the suction nozzle overlaps the seal housing radially and axially, the seal housing is shielded from unwanted external influences. Accordingly, the suction port serves as a cover for the seal housing. The suction port is preferably detachably attached to the outside of the housing wall. Particularly preferably, the suction port is flanged detachably onto the outside of the housing wall.

According to the invention, the suction nozzle has an internal nozzle section, by means of which the seal housing is shielded from a flow of the fluid to be sucked in. In this case, the nozzle section serves on the one hand for a streamlined flow to the inlet opening. On the other hand, the nozzle section serves to cover the seal housing against the flow of the fluid to be sucked in. This in particular avoids any solids contained in the compressible fluid to be conveyed hitting the seal housing and impairing the function of the seal housing and/or the contact seal arrangement.

In a further embodiment of the invention, the at least one sealing element has at least one lip sealing ring. Accordingly, the contact seal arrangement can be designed in the form of a wave lip seal, with the sealing surface arranged on the impeller forming a type of wave, so to speak. In any case, wave lip seals are known as such in principle in the field of sealing technology and in the present case have proven to be particularly advantageous in a surprising way and to an unexpected extent.

Fig. 1

zeigt in schematischer Seitenansicht mit axial gerichteter Blickrichtung eine Ausführungsform eines erfindungsgemäßen Hochdruckradialventilators, wobei die Darstellung teilweise auch verdeckte Linien zeigt,

Fig. 2

in einer schematischen Schnittdarstellung entlang eines Radialschnitts II-II gemäß Fig. 1 den Hochdruckradialventilator nach Fig. 1,

Fig. 3

in einem perspektivisch gedrehten schematischen Radialschnitt den Hochdruckradialventilator nach den Fig. 1 und 2,

Fig. 4

in teilweise abgeschnittener vergrößerten Detaildarstellung einen Bereich IV der Schnittdarstellung nach Fig. 2,

Fig. 5

eine perspektivisch gedrehte Ansicht der vergrößerten Schnittdarstellung nach Fig. 4,

Fig. 6

in perspektivischer Ansicht eine Darstellung eines Laufrads des Hochdruckradialventilators nach den Fig. 1 bis 5,

Fig. 7

das Laufrad nach Fig. 6 unter zeichnerischer Ausblendung einer Deckscheibe mit Blickrichtung auf eine aus mehreren Laufschaufeln gebildete Beschaufelung,

Fig. 8

in vergrößerter perspektivischer Detaildarstellung einen Einlaufring des Laufrads,

Fig. 9

in einer Seitenansicht mit axial orientierter Blickrichtung ein Dichtungsgehäuse des Hochdruckradialventilators und

Fig. 10

in einer perspektivischen Explosionsdarstellung einzelne Bauteile des Dichtungsgehäuses nach Fig. 9 sowie ein in dem Dichtungsgehäuse aufgenommenes Dichtelement.

Further advantages of the invention result from the following description of a preferred exemplary embodiment of the invention, which is illustrated using the drawings. The features of the invention are solely determined by the following claims.

1

shows a schematic side view with an axial direction of view of an embodiment of a high-pressure centrifugal fan according to the invention, the representation also showing partially hidden lines,

2

in a schematic sectional view along a radial section II-II according to 1 the high-pressure centrifugal fan 1 ,

3

in a perspective rotated schematic radial section the high-pressure centrifugal fan after the 1 and 2 ,

4

in a partially truncated enlarged detailed view, a region IV of the sectional view 2 ,

figure 5

a rotated perspective view of the enlarged sectional view 4 ,

6

a perspective view of an impeller of the high-pressure centrifugal fan according to FIG Figures 1 to 5 ,

7

the impeller 6 with graphical hiding of a shroud looking in the direction of a blading formed from several rotor blades,

8

an inlet ring of the impeller in an enlarged perspective detail view,

9

in a side view with an axially oriented viewing direction, a seal housing of the high-pressure centrifugal fan and

10

in a perspective exploded view of individual components of the seal housing 9 and a seal member housed in the seal case.

A high-pressure centrifugal fan 1 according to Figures 1 to 5 is provided for the pressure-increasing delivery of a compressible fluid, not designated in any more detail, and has a volute housing 2 and an impeller 3 .

The volute housing 2 has a spiral-shaped design, known as such in principle, with regard to a flow-effective cross section, which is not described in any more detail, and is provided with an inlet opening 4 and an outlet opening 5 . The inlet opening 4 (cf. Figures 4, 5 ) is presently extended through a housing wall 6 of the volute casing 2 and serves as an inlet for the fluid to be pumped into the volute casing 2. The outlet opening 5 opens into an outlet connection 7 arranged on the volute casing 2. The volute casing 2 is presently designed as a sheet metal construction. In this case, the spiral housing 2 in the present case has in particular a first cover plate 8 forming the housing wall 6, a second cover plate 9 arranged at an axial distance therefrom, and a peripheral plate 10 connecting the two cover plates 8, 9 to one another in a fluid-tight manner on an outer circumference. The two cover plates 8, 9 present an approximately annular basic shape with an approximately spiral-shaped outer contour and are axially offset from one another to form a receiving space 11 and arranged in parallel.

The impeller 3 is arranged in the spiral housing 2 so that it can rotate about an axial axis of rotation D and has blading 13 formed from a plurality of moving blades 12 ( 7 ). In the present case, the impeller 3 is accommodated in the accommodation space 11 of the spiral housing 2 formed between the cover plates 8 , 9 . An inner circumference 14 of the impeller 3 is arranged on an outer circumference 15 of a drive shaft 16 and is connected to it in a rotationally fixed manner in a basically known manner. The drive shaft 16 is assigned to a drive motor in the form of an electric motor, which is not shown in detail in the drawing. Alternatively, the drive shaft can be assigned to an intermediate bearing. How in particular based on 7 As can be seen, the rotor blades 12 are each formed radially curved in the present case. In this case, the direction of curvature of the rotor blades 12 is opposite to an intended direction of rotation R of the rotor wheel 3, so that one can speak of backward-curved rotor blades 12.

When the impeller 3 is rotating in the direction of rotation R, the blading 13 sucks the compressible fluid to be conveyed in the axial direction and thus in the direction of the axis of rotation D through the inlet opening 4 and the fluid flows in a primarily radially deflected and also tangentially deflected direction through the outlet opening 5 of the Spiral housing 2. In this way, the blading 13 causes a pressure-increasing delivery of the fluid, starting from an inlet-side suction side S and an outlet-side pressure side P. Based on 2 In the present case, the suction side S is assigned to a region upstream of the inlet opening 4 in the direction of flow. The pressure side P is assigned to an outer circumference of the impeller 3 for the sake of simplicity.

In order to counteract an undesirable pressure equalization between the pressure side P and the suction side S - caused by gap losses - a sealing arrangement 17 ( Figures 4, 5 ) intended. The sealing arrangement 17 is formed between the spiral housing 2 and the impeller 3 in a manner to be described in more detail below and serves to minimize an undesirable pressure loss between the pressure side P and the suction side S.

How in particular based on the Figures 4 and 5 As can be seen, the sealing arrangement 17 has a contact sealing arrangement 18 arranged in the region of the inlet opening 4 . The contact sealing arrangement 18 seals an annular gap 20 formed between a boundary 19 of the inlet opening 4 and the impeller 3 . In this case, the contact seal arrangement arranged on the impeller 3 sealing surface 21, the particular based on 6 and 8th can be seen, and at least one sealing element 22 contacting the sealing surface 21 . The sealing element 22 is releasably attached to an outer side 23 of the housing wall 6 in a manner that will be described in more detail below. The outside 23 faces away from the installation space 11 .

How based 4 As can be seen, the contact seal arrangement 18 counteracts an undesired outflow of the fluid, starting from a gap space 25 formed between the impeller 3 and an inner side 24 of the housing wall 6, through the inlet opening 4 in the direction of the outer side 23 and thus in the direction of the suction side S.

In the present case, the sealing element 22 is fixed to the housing. In contrast, the sealing surface 21 moves together with the impeller 3 when the impeller 3 rotates.

How further in particular based on 6 As can be seen, the impeller 3 has a cover disk 26 in the present case. The blading 13 is covered axially on the front side by means of the cover plate 26 . The sealing surface 21 is arranged on an inlet ring 27 assigned to the cover disk 26 . The inlet ring 27 projects in the direction of the outside 23 of the housing wall 6 into and/or through the inlet opening 4 of the volute housing 2 and borders an inlet opening 28 of the impeller 3 . The blading 13 is arranged between the support disk T and the cover disk 26 in the axial direction. In this respect, one can also speak of a closed design of the impeller 3, which is basically known as such. The sealing surface 21 is arranged on a lateral surface of the inlet ring 27 lying on the outside in the radial direction, with a normal direction of the sealing surface, not designated in any more detail, being oriented radially outwards. In the present case, the inlet ring 27 is manufactured in the form of a separately formed component and joined to the cover disk 26 . For example, the inlet ring 27 can be welded to the cover disk 26 . The cover disk 26 has a circular ring-shaped basic shape, with the inlet ring 27 being attached in a fluid-tight manner to an inner circumference of the cover disk 26 (not designated in any more detail). The inlet ring 27 has a flow-effective shape on its inner side facing away from the sealing surface 21 in the radial direction and acts at the same time as a diffuser. Since the inlet ring 27 protrudes in the axial direction—to put it simply—at least in sections through the inlet opening 4 of the volute casing 2, the sealing point formed between the sealing surface 21 and the sealing element 22 is easily accessible from the outside and thus starting from the outside 23 Manufacture, maintenance and/or servicing of the high-pressure centrifugal fan 1 is significantly simplified in a particularly advantageous manner.

In an embodiment not shown in the drawing, the inlet ring 27 can be of comparatively simple design and merely in the form of an axially extending pipe socket, which can be attached to the inner circumference of the cover disk 26 with an approximately right-angled transition. Accordingly, the particular basis of Figures 4 and 5 apparent curved, diffuser-like design of the inlet ring 27 is not mandatory.

How further in particular based on the Figures 9 and 10 As can be seen, the contact seal arrangement 18 has a seal housing 29 in the present case. The seal housing is arranged on the outside 23 of the housing wall 6 and has an installation space 30 in which the at least one sealing element 22 is accommodated.

The seal housing 29 has an annular basic shape and is arranged coaxially to the axis of rotation D in the assembled state. Thus, in the present case, the seal housing 29 is arranged coaxially to the inlet opening 4 , the inlet opening 28 and to the impeller 3 .

The installation space 30 is designed to complement the shape of the sealing element 22 and in the present case has an annular shape. The sealing element 22 is fitted into the installation space 30 in a ready-to-operate state (cf. Figures 4, 5 ). In the present case, the sealing housing 29 has a housing cover 31 and a housing base 32 , the housing cover 31 releasably closing the installation space 30 presently formed on the housing base 32 .

Here, the entire seal housing 29 is detachably flanged onto the outside 23 of the housing wall 6 by means of a plurality of fastening elements 33 . A total of eight nuts, not specified, are provided as fastening elements 33 , spaced evenly in the circumferential direction. In an embodiment that is not shown, the seal housing can be connected to the housing wall by means of screws.

In addition, the volute housing 2 has a suction port 34 in the present case. The suction port 34 is used to advantageously supply the fluid in the direction of the inlet opening 4 and/or the inlet opening 28 and is tubular in the present case. The intake port 34 is oriented coaxially to the inlet opening 4 and/or the inlet opening 28 and has a circular cross section. The suction port 34 is presently provided with a flange 35 which by means of several unspecified fasteners on the outside 23 of the Housing wall 6 is flanged. In this case, the suction port 34 overlaps the seal housing 29 both in the radial and in the axial direction. In this respect, the suction port 34 acts as a kind of cover for the seal housing 29.

The suction nozzle 34 also has an internal nozzle section 36 . The nozzle section 36 is arranged upstream of the seal housing 29 in the direction of flow of the fluid and is fastened to an inner circumference of the suction nozzle 34 (not designated in any more detail). For example, the nozzle section 36 can be welded into the inner circumference of the suction nozzle 34 . The seal housing 29 is shielded from a flow of the fluid to be sucked in by means of the nozzle section 36 . For this purpose, the nozzle section 36 has a streamlined shape in the present case. The shape of the nozzle section 36 is here adapted to the flow-effective design of the inlet ring 27 . How in particular based on the Figures 4 and 5 As can be seen, a radial course that is essentially continuous in the axial direction is provided between an inner contour of the nozzle section 36 and an inner contour of the inlet ring 27 .

In the present case, the sealing element 22 is in the form of a lip sealing ring. The lip seal ring 22 is made of an elastomeric material. In the based on the Figures 4 and 5 In the installation state that can be seen, a radially inner tip of the lip seal ring 22 is directed axially outward. In the present case, the lip seal ring 22 is held in a non-positive manner on its outer circumference between the housing cover 31 and the housing base 32 . In the case of embodiments that are not shown, annular sealing elements made of carbon, PTEE or other materials can be provided, depending on the conditions of use and/or area of application of the high-pressure centrifugal fan.

Claims (4)

1. High-pressure radial ventilator (1) for pressure-increasing conveyance of a compressible fluid with a spiral housing (2) comprising an inlet opening (4) for fluid intake and an outlet opening (5) for fluid output, extending through a housing partition (6), and with a rotor (3) that rotates around an axial rotational axis (D) in the spiral housing (2) and a blading (13) made from multiple rotor blades (12),

   whereby the blading (13), when the rotor (3) is rotating, induces an axial suction of the fluid through the inlet opening (4) and a radially and/or tangentially diverted drainage of the fluid through the outlet opening (5) and thus a pressure-increasing conveyance of the fluid from a suction side (S) to a pressure side (P), and

   with a seal arrangement (17) between the spiral housing (2) and the rotor (3) that serves to minimize pressure loss between the pressure side (P) and the suction side (S),

   whereby the rotor (3) comprises a cover pane (26) via which the blading (13) is axially covered on the front side,

   whereby the rotor (3) comprises a seal surface (21), and whereby the seal surface (21) is positioned on an intake ring (27) on the cover pane (26) such that the intake ring (27) borders an intake opening (28) of the rotor (3),

   whereby the seal arrangement (17) comprises a contact seal arrangement (18) in the area of the inlet opening (4),

   whereby the intake ring (27) extends axially toward an outer side (23) of the housing partition (6) through the inlet opening (4),

   whereby the contact seal arrangement (18) comprises the seal surface (21) on the rotor (3) and at least one seal element (22) touching the seal surface (21),

   whereby the contact seal arrangement (18) seals a ring gap (20) between an edge (19) of the inlet opening (4) and the rotor (3),

   whereby the seal element (22) is removably fastened on the outer side (23) of the housing partition (6), whereby the

   contact seal arrangement (18) comprises a seal housing (29) with an installation space (30) on the outer side (23) of the housing partition (6) where the at least one seal element (22) is received,

   characterized in that the spiral housing (2) comprises a suction nozzle (34) opening up into the inlet opening (4) that radially and axially overlaps with the seal housing (29), and

   that the suction nozzle (34) comprises an internal nozzle segment (36) via which the seal housing (29) is shielded against the flow of the fluid being suctioned.
2. High-pressure radial ventilator (1) as per claim 1, characterized in that the seal housing (29) is adjustably flanged onto the exterior (23) of the housing wall (6) via multiple fastening elements (33).
3. High-pressure radial ventilator (1) as per one of the preceding claims, characterized in that the at least one seal element is designed in the form of a radial shaft sealing ring, a brush element, or a lip sealing ring.
4. High-pressure radial ventilator (1) as per one of the claims 1 or 2, characterized in that the contact seal arrangement comprises a gland seal.

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