Compensator for rotary furnaces

Abstract

The invention relates to a compensator for rotary furnaces with an inner side, directed inwards, and an outer side, directed outwards, said compensator comprising, from the inner side to the outer side, an inner layer, a thermal pre-insulation layer, a first thermal insulation layer, a first film, a second thermal insulation layer, a second film, a third thermal insulation layer and an outer layer. The first film and the second film are designed to reduce and / or stop a fluid flow. Furthermore, the compensator is designed to compensate translational and rotational movements between a rotary tube and a rotary furnace housing.

Description

[0001] Compensator for rotary kilns

[0002] Description

[0003] The invention relates to a compensator for rotary kilns.

[0004] Expansion joints are generally referred to as expansion compensators and are used in industrial systems. They are installed to compensate for movements and stresses, for example, due to thermal expansion in piping systems and ducts, as well as in components (e.g., pumps). Expansion joints can be made of metal, rubber, or fabric. In highly stressed fabric expansion joints, the primary function is not only to absorb movement but also to reduce temperature.

[0005] Typically, expansion joints for media with temperatures above 750°C are provided with a lining on the inside of the rotary tube. This is not possible in many applications. Expansion joints for high-temperature applications should also be economically viable and have a long service life.

[0006] The object of the invention is to provide a compensator for high-temperature applications with a medium temperature greater than 750°C which is simple and cost-effective to manufacture and which does not require any lining on the inside of the rotary kiln.

[0007] This problem is solved by a compensator having the features of claim 1.

[0008] The compensator according to the invention for rotary kilns with the features of claim 1, with an inwardly directed inner side and an outwardly directed outer side, comprising, from the inside to the outside, an inner layer, a thermal pre-insulation layer, a first thermal insulation layer, a first film, a second thermal insulation layer, a second film, a third thermal insulation layer, and an outer layer. The first film and the second film are designed to reduce and / or stop a fluid flow. Furthermore, the compensator is designed to compensate for translational and rotational movements between a rotary kiln and a rotary kiln housing. The compensator has a high temperature resistance and can reduce the temperatures from the inside to the outside.In particular, the compensator is designed to have a long-term temperature resistance of up to 1000° C on the inside without the need for brick lining of the compensator.

[0009] The compensator is preferably mounted between a static housing of the rotary kiln and a seal that seals the rotary kiln to the static housing. The seal preferably comprises a rotating unit attached to the rotary kiln and a static unit on which the compensator is arranged. The seal accommodates translational and rotational movements of the rotary kiln. These movements can be due to thermal changes in length, vibrations, or settlement phenomena of the rotary kiln.

[0010] The inner layer borders one side of the rotary kiln and allows the absorption of pressures from the system. Pressures of up to 5900 Pa and temperatures of up to 1000°C can occur on the product side. Furthermore, the inner layer stabilizes the compensator. The pre-insulation layer, the first insulation layer, the second insulation layer, and the third insulation layer serve to reduce the temperature from the inside to the outside. The first foil arranged between the first insulation layer and the second insulation layer, as well as the second foil arranged between the second insulation layer and the third insulation layer, form a fluid-impermeable barrier to reduce or stop fluid flow from the inside to the outside. This prevents fluid from penetrating colder layers of the compensator and condensing there.The outer layer can protect the compensator from weather influences and external mechanical impacts.

[0011] The subclaims show further preferred developments of the invention.

[0012] The compensator preferably comprises a first side insulation layer and a second side insulation layer. The first side insulation layer is arranged at a first axial end of the compensator and the second side insulation layer at a second axial end of the compensator. The first side insulation layer and the second side insulation layer are arranged in particular radially between the thermal

[0013] The first and second side insulation layers are arranged between the pre-insulation layer and the outer layer. Thus, the first and second side insulation layers prevent heat from creeping from the inside to the axial ends of the compensator. Preferably, the sealing layers of the first and second side insulation layers are aligned perpendicular to the other insulation layers of the compensator to improve thermal insulation toward the axial ends.

[0014] The compensator is further preferably configured to be arranged on a metal frame. The outer layer can be fixed to the metal frame at the first axial end and the second axial end. In particular, the outer layer is attached to the metal frame using a clamping strip with circumferential screw connection. The outer layer has high mechanical strength and can transfer forces from the metal frame to the other layers. Thus, not every layer of the compensator needs to be fixed to the metal frame. The metal frame preferably has two parts configured to be attached to two different pipe ends, so that the compensator attached to the metal frame connects the pipe ends to one another.

[0015] The outer layer preferably comprises a composite layer of a glass fiber fabric and a metal foil, in particular a steel foil, arranged between two layers of wire mesh. Thus, the outer layer forms a gas-tight barrier. In particular, the composite layer of the outer layer comprises three layers of glass fiber fabric separated by two steel foils arranged between them. The wire mesh provides additional mechanical protection and improves the dimensional stability of the outer layer.

[0016] Particularly preferably, the first axial end and the second axial end of the outer layer are enclosed by a steel foil. The steel foil forms a fluid-tight layer. This prevents fluid from escaping at the axial ends of the outer layer.

[0017] The inner layer of the compensator preferably comprises at least one layer of wire mesh. In particular, the wire mesh is made of a metal with good mechanical properties and high temperature resistance. Thus, the inner layer can stabilize the compensator on the inside even at high temperatures and enables reliable absorption of pressures exerted by the rotary kiln on the inside of the compensator.

[0018] According to a preferred embodiment of the invention, the pre-insulation layer and / or the first insulation layer and / or the second insulation layer and / or the third insulation layer comprise a plurality of insulation layers. If the compensator comprises a first and second side insulation layer, this also preferably comprises a plurality of insulation layers. Insulation layers enable efficient temperature reduction from the inside to the outside of the compensator. An insulation layer is preferably designed to reduce approximately 100°C towards the outside. Particularly preferably, the pre-insulation layer and / or the first insulation layer and / or the second insulation layer and / or the third insulation layer comprise at least one quilted fiber mat arranged between two high-temperature fabric layers.If the compensator comprises a first and second side insulation layer, these also preferably have at least one quilted fiber mat arranged between two high-temperature fabric layers. Fiber mats enable efficient and reliable temperature reduction toward the outside. The high-temperature fabric layers improve the mechanical properties and temperature resistance of the respective insulation layer.

[0019] Preferably, the high-temperature fabric layer of the pre-insulation layer and / or the first insulation layer and / or the second insulation layer is a silicate fabric. Silicate fabrics can withstand continuous temperatures above 1,000 °C without significant dimensional changes, even during thermal shocks. They are also characterized by very low thermal conductivity and good chemical resistance. Thus, the use of silicate fabric in the insulation layers enables reliable operation of the compensator with high temperature resistance.

[0020] More preferably, the high-temperature fabric layer of the third insulation layer is a fiberglass fabric. Fiberglass fabrics have high thermal and insulating properties and can be used at temperatures up to 700°C. Fiberglass fabrics are more cost-effective than silicate fabrics and can be coated with various materials to adapt the properties of the fiberglass fabric to specific requirements.

[0021] The pre-insulation layer preferably has a larger number of stacked fiber mats than the first insulation layer and / or the second insulation layer and / or the third insulation layer. Thus, a large portion of the temperature can be dissipated in the pre-insulation layer, so that the subsequent layers toward the outside are exposed to a lower temperature load.

[0022] Preferably, the first foil and / or second foil is a metal foil, in particular a steel foil. Steel foils exhibit high fluid tightness, while simultaneously offering good mechanical properties and high chemical resistance. Thus, the steel foil can form a reliable fluid barrier in the compensator.

[0023] According to a further preferred embodiment of the invention, the compensator comprises a funnel assembly configured to be attached to a connection and to convey a product from the inside of the compensator to the connection. Consequently, a product accumulating on the inside of the compensator can be discharged via the funnel assembly.

[0024] Preferably, the funnel assembly comprises a first discharge line and a second discharge line. The first discharge line can be attached to a first connection, and the second discharge line can be attached to a second connection. The two discharge lines form a redundant system and can improve the operational reliability of the funnel assembly.

[0025] More preferably, the funnel assembly comprises, from the inside to the outside, an inner layer, a first thermal insulation layer, a first film, and an outer layer. The transition from the compensator to the funnel assembly is preferably quilted, sewn, or stapled. Since the funnel assembly is preferably located farther from the process area than the compensator, the funnel assembly can be designed for a lower temperature load than the compensator. Thus, the funnel assembly can have a thinner structure with fewer layers than the compensator.

[0026] Further details, advantages, and features of the present invention will become apparent from the following description of a preferred embodiment with reference to the drawing. It shows:

[0027] Fig. 1 is a schematic sectional view along a central axis of a compensator for a rotary kiln according to the preferred embodiment,

[0028] Fig. 2 is a schematic detailed view of the compensator according to the preferred embodiment in the region of a first axial end,

[0029] Fig. 3 is a schematic detailed view of an outer layer of the compensator according to the preferred embodiment,

[0030] Fig. 4 is a schematic exploded view of the compensator according to the preferred embodiment,

[0031] Fig. 5. a temperature profile diagram of layers of the compensator from an inside to an outside according to the preferred embodiment,

[0032] Fig. 6 is a second schematic sectional view perpendicular to the central axis of the compensator according to the preferred embodiment, and

[0033] Fig. 7 is a schematic detailed view through the layers of a funnel arrangement on the compensator according to the preferred embodiment. A compensator 1 according to a preferred embodiment of the invention is described in detail below with reference to Figures 1 to 7.

[0034] Figure 1 shows the compensator 1 for a rotary kiln. The compensator 1 is a fabric compensator that is rotationally symmetrical about a central axis X - X. The central axis X - X is preferably arranged coaxially with a longitudinal axis of a rotary kiln's rotary kiln.

[0035] In the direction of the central axis X - X, the compensator 1 has an inner side 10. Furthermore, the compensator 1 has an outwardly directed outer side 12.

[0036] In the axial direction R2 of the central axis X-X, the compensator 1 has a first axial end 11 and a second axial end 13. At the first axial end 11 and the second axial end 13, the compensator 1 is arranged flush with a metal frame 39.

[0037] From the inner side 10 to the outer side 12, the compensator 1 has, in succession, an inner layer 20, a thermal pre-insulation layer 22, a first thermal insulation layer 24, a first film 26, a second thermal insulation layer 28, a second film 30, a third thermal insulation layer 32 and an outer layer 34.

[0038] Furthermore, a first side insulation layer 36 is arranged at the first axial end 11, and a second side insulation layer 37 is arranged at the second axial end 12. The first and second side insulation layers 36, 37 are arranged in the radial direction R1 between the pre-insulation layer 22 and the outer layer 34. The first thermal insulation layer 24, the first foil 26, the second insulation layer 28, the second foil 30, and the third insulation layer 32 are thus arranged in the axial direction R2 relative to the central axis X-X between the first side insulation layer 36 and the second side insulation layer 37. The layer structure according to the invention enables a temperature reduction from the inner side 10 to the outer side 12. The first and second side insulation layers 36, 37 prevent creeping heat flows toward the first and second axial ends 11, 12 of the compensator 1.Furthermore, the layer structure of the compensator 1 is flexible and thus allows the absorption of movements.

[0039] The metal frame 39 has a first segment 39a and a second segment 39b, which are connected to each other only via the compensator 1. The first segment 39a is arranged at the first axial end 11 of the compensator 1. The outer layer 34 is fixed at the first axial end 11 to the first segment 39a of the metal frame 39 by a clamping strip 33. The second segment 39b is arranged at the second axial end 13 of the compensator 1, with the second segment 39b fixing the outer layer 34 to a second axial end 13 via a clamping strip 33. The compensator 1 is designed to compensate for translational and rotational movements between the first segment 39a and the second segment 39b.

[0040] The first segment 39a is configured to be attached to a sealing ring. A portion of the sealing ring is preferably attached to the rotary tube of the rotary kiln, so that the sealing ring can seal a process area of ​​the rotary kiln from the atmosphere. The sealing ring moves synchronously with the rotary tube, except for the rotational movement.

[0041] The second segment 39b is designed to be attached to a static component of the rotary kiln. Thus, the compensator 1 compensates, in particular, for thermal length changes and vibrations of the rotary kiln relative to the static component of the rotary kiln.

[0042] Figure 2 shows a schematic detailed view of the compensator 1 from Figure 1 in the area of ​​the first axial end 11. The compensator is constructed equivalently in the area of ​​the second axial end 13.

[0043] Figure 2 shows that the metal frame 39 is assembled from several sheets welded together.

[0044] The first side insulation layer 36 is attached to the first segment 39a of the metal frame 39 via a fastening means 21. Furthermore, the pre-insulation layer 22 and the inner layer 20 are also attached to the first segment of the metal frame 39 via a fastening means 21.

[0045] The terminal block 33 comprises two components aligned parallel to each other, which fix the outer layer 34 by means of a screw connection.

[0046] The schematic detailed view in Figure 2 also shows the layer structure of the insulation layers of the compensator 1. The pre-insulation layer 22 comprises three superimposed quilted fiber mats 44, which are arranged parallel to the central axis X - X. The quilted fiber mats 44 of the pre-insulation layer 22 are enclosed by a high-temperature fabric layer of silicate fabric 45.

[0047] The first insulation layer 24, the second insulation layer 28, and the third insulation layer 32 comprise two quilted fiber mats 44 arranged one above the other, which are arranged parallel to the central axis XX. The quilted fiber mats 44 of the first insulation layer 24 and the second insulation layer 28 are each enclosed by a high-temperature fabric layer made of silicate fabric 45. The quilted fiber mats 44 of the third insulation layer 32 are enclosed by a high-temperature fabric layer made of glass fiber fabric 40. The first and second side insulation layers 36, 37 comprise two quilted fiber mats 44 arranged one above the other in the axial direction R2 relative to the central axis X-X.

[0048] Figure 3 shows a detailed view of the outer layer 34 in the region of the first axial end 11. The individual layers of the outer layer 34 are shown in Figure 3.

[0049] The outer layer 34 consists of a layer composite 43 of several layers extending from the first axial end 11 to the second axial end 12. The innermost and outermost layers of the layer composite 43 are a wire mesh 42, in particular a wire mesh 42 with a 16 x 16 mm mesh size. The wire mesh 42 serves as a support layer for the outer layer 34 and protects it from damage.

[0050] In the radial direction R1, a glass fiber fabric layer 40, a steel foil 41, a second glass fiber fabric layer 40, a further steel foil 41, and a third glass fiber fabric layer 40 are arranged alternately between the two wire meshes 42. The steel foils 41 form a barrier layer for a fluid that rests against the inner side 10 of the compensator 1.

[0051] The glass fiber fabrics 40 improve the mechanical properties of the outer layer 34, in particular its tear resistance.

[0052] The first and second axial ends 11, 13 of the outer layer 34 are enclosed by a steel foil 41 and a glass fiber fabric 40. This prevents fluid from escaping from the compensator 1 laterally at the outer layer.

[0053] Figure 4 shows an exploded view of the individual layers of the compensator 1.

[0054] Starting from the inner side 10, the compensator 1 first comprises the inner layer 20, which comprises several layers of the wire mesh 42. The pre-insulation layer 22 adjoins the inner layer 20 on the outside.

[0055] From the outer side 12, the compensator 1 first has the outer layer 34 made of a layered composite 43. In the radial direction R1, between the pre-insulation layer 22 and the outer layer 34, a first side insulation layer 36 is arranged at the first axial end 11 of the compensator 1, and a second side insulation layer 37 is arranged at a second axial end 12 of the compensator 1.

[0056] The first insulation layer 24, the first foil 26, the second insulation layer 28, the second foil 30, and the third insulation layer 32 are arranged one above the other in the radial direction R1 from the inner side 10, centrally between the first side insulation layer 36, the second side insulation layer 37, the pre-insulation layer 22, and the outer layer 34. Figure 5 shows a diagram of a temperature profile t in and on the compensator 1 as a function of the individual layers L. Table 1 shows the corresponding values ​​for the diagram in Figure 5. The temperature t is measured in the center of each individual layer L after a stable measured value has been obtained.

[0057] Position L0 refers to the surface of the compensator 1 on the inner side 10, which is designed to contact a medium. Position L30 refers to the surface of the compensator 1 on the outer side 12, which is designed to contact the ambient air. The compensator 1 has a temperature t of 1000°C at position L0. This temperature is reduced to 54.39°C by position L30.

[0058] The inner layer 20 comprises layers L1 to L3. Layers L1 and L2 are a 42-gauge wire mesh with a mesh size of 16 x 16 mm (WM 16x16). Layer L3 is a 42-gauge wire mesh with a mesh size of 24 x 110 mm (WM 24x110). The temperature t decreases from layer L1 to layer L3 from 989.59°C to 959.56°C.

[0059] The pre-insulation layer 22 comprises layers L4 to L8. Layers L4 and L8 are made of a silicate fabric 45 (HS 600), and layers L5 to L7 are made of a quilted fiber mat 44 (CMS 250). The temperature t decreases from layer L4 to layer L8 from 989.55°C to 693.50°C. Each layer of quilted fiber mat 44 reduces the temperature t by approximately 100°C.

[0060] The first insulation layer 24 comprises layers L9 to L12. Layers L9 and L12 are made of a silicate fabric 45 (HS 600), and layers L10 and L11 are made of a quilted fiber mat 44 (CMS 250). The temperature t decreases from 691.40°C to 493.34°C between layer L9 and layer L12.

[0061] Layer L13 refers to the first foil 26 and is made of a high-fatigue-resistant stainless steel foil (SFHS). Layer L13 has a temperature t of 491.23°C.

[0062] The second insulation layer 28 comprises layers L14 to L17. Layers L14 and L17 are made of a silicate fabric 45 (HS 600), and layers L15 and L16 are made of a quilted fiber mat 44 (CMS 250). The temperature t decreases from layer L14 to layer L17 from 490.83°C to 383.87°C.

[0063] Layer L18 refers to the second foil 30 and is made of a high-fatigue-resistant stainless steel foil (SFHS). Layer L18 has a temperature t of 285.89°C.

[0064] The third insulation layer 32 comprises layers L19 to L22. Layers L19 and L22 are made of a glass fiber fabric 40 (KE 1400HT), and layers L20 and L21 are made of a quilted fiber mat 44 (CMS 250). The temperature t decreases from layer L19 to layer L22 from 285.48°C to 82.65°C.

[0065] The outer layer 34 comprises layers L23 to L29. Layers L23 and L29 are made of a 42-gauge wire mesh with a mesh size of 16 x 16 mm (WM 16x16). Layers L24, L26, and L28 are made of a 40-gauge glass fiber mesh (KE 1400HT), and layers L25 and L27 are made of a high-fatigue stainless steel foil (SFHS). The temperature t decreases from layer L23 to layer L29 from 75.77°C to 54.31°C.

[0066] Figure 6 shows schematically a section of the compensator 1 perpendicular to the central axis X - X. At a lower end of the compensator 1, a funnel arrangement 38 is arranged.

[0067] The funnel arrangement 38 comprises a first discharge line 38a, which is attached to a first connection 46, and a second discharge line 38b, which is attached to a second connection 47. The first discharge line 38a and the second discharge line 38b are frustoconical and connected by a web 48. The web preferably has the structure of the compensator 1. The funnel arrangement 38 is configured to convey a product from the inner side 10 of the compensator 1 to the first and / or second connection 46, 47.

[0068] The minimum angle between the horizontal and the first and / or second derivative 38a, 38b is preferably 62°, and the maximum angle between the horizontal and the first and / or second derivative 38a, 38b is preferably 65°. The first derivative 38a and the second derivative 38b are preferably mirror-symmetrical to a vertical plane lying on the central axis X-X.

[0069] Figure 7 shows a schematic layer structure of the funnel arrangement 38. From the inner side 10 to the outer side 12, the funnel arrangement 38 has an inner layer 20, a thermal insulation layer 24, a first film 26 and an outer layer 34.

[0070] The inner layer 20, thermal insulation layer 24, first film 26, and outer layer 34 of the funnel arrangement 38 are preferably constructed equivalently to the corresponding layers of the compensator 1. The transitions between the layers of the funnel arrangement 38 and the compensator 1 are preferably quilted, sewn, and / or stapled.

[0071] In addition to the above written description of the invention, reference is hereby explicitly made to the drawings in the figures for supplementary disclosure. Table 1: Temperature profile along the compensator layers List of reference symbols

[0072] I Compensator

[0073] 10 Inside

[0074] II First axial end

[0075] 12 Outside

[0076] 13 second axial end

[0077] 20 inner layer

[0078] 21 Fasteners

[0079] 22 Thermal pre-insulation layer

[0080] 24 First insulation layer

[0081] 26 First slide

[0082] 28 Second insulation layer

[0083] 30 Second slide

[0084] 32 Third insulation layer

[0085] 33 terminal block

[0086] 34 Outer layer

[0087] 36 First side insulation

[0088] 37 First side insulation

[0089] 38 funnel arrangement

[0090] 38a First derivative

[0091] 38b Second derivative

[0092] 39 metal frames

[0093] 39a First segment

[0094] 39b Second segment

[0095] 40 glass fiber fabrics

[0096] 41 steel foil

[0097] 42 wire mesh

[0098] 43 layer composite

[0099] 44 Quilted fiber mat

[0100] 45 silicate fabric

[0101] 46 First connection

[0102] 47 Second connection

[0103] 48 jetty

[0104] R1 radial direction

[0105] R2 axial direction

[0106] X — XCenterline

Claims

Claims 1. Compensator for rotary kilns with an inwardly directed inner side (10) and an outwardly directed outer side (12), comprising from the inner side (10) to the outer side (12) . an inner layer (20), . a thermal pre-insulation layer (22), a first thermal insulation layer (24), . a first film (26) which is arranged to reduce and / or stop a fluid flow, a second thermal insulation layer (28), . a second film (30) which is arranged to reduce and / or stop a fluid flow, . a third thermal insulation layer (32), and . an outer layer (34), . wherein the compensator (1) is designed to compensate for translational movements and rotational movements between a rotary kiln and a rotary kiln housing.

2. Compensator according to claim 1, comprising a first side insulation layer (36) which is arranged at a first axial end (11) of the compensator, and a second side insulation layer (37) which is arranged at a second axial end (13) of the compensator (1), in particular wherein the first side insulation layer (36) and the second side insulation layer (37) are arranged radially between the thermal pre-insulation layer (22) and the outer layer (34).

3. Compensator according to one of the preceding claims, wherein the compensator (1) is adapted to be arranged on a metal frame (39), wherein the outer layer (34) is adapted to be fixed to the metal frame (39) at the first axial end (11) and the second axial end (13).

4. Compensator according to one of the preceding claims, wherein the outer layer (34) comprises a layer composite (43) made of a glass fiber fabric (40) and a metal foil, in particular a steel foil (41), which is arranged between two layers of wire mesh (42).

5. Compensator according to claim 3 or 4, wherein the first axial end (11) and the second axial end (13) of the outer layer (34) are enclosed by a steel foil (41).

6. Compensator according to one of the preceding claims, wherein the inner layer (20) comprises at least one layer of wire mesh (42).

7. Compensator according to one of the preceding claims, wherein the pre-insulation layer (22) and / or the first insulation layer (24) and / or the second insulation layer (28) and / or the third insulation layer (32) and / or the first side insulation layer (36) and / or the second side insulation layer (37) have a plurality of insulation layers.

8. Compensator according to claim 7, wherein the pre-insulation layer (22) and / or the first insulation layer (24) and / or the second insulation layer (28) and / or the third insulation layer (32) and / or the first side insulation layer (36) and / or the second side insulation layer (37) comprise at least one quilted fiber mat (44) arranged between two high-temperature fabric layers.

9. Compensator according to claim 8, wherein the high-temperature fabric layer of the pre-insulation layer (22) and / or the first insulation layer (24) and / or the second insulation layer (28) is a silicate fabric (45).

10. Compensator according to claim 8 or 9, wherein the high-temperature fabric layer of the third insulation layer (32) is a glass fiber fabric (40).

11. Compensator according to one of claims 8 to 10, wherein the pre-insulation layer (22) has a larger number of fiber mats arranged one above the other than the first insulation layer (24) and / or the second insulation layer (28) and / or the third insulation layer (32).

12. Compensator according to one of the preceding claims, wherein the first foil and / or second foil is a metal foil, in particular a steel foil (41).

13. Compensator according to one of the preceding claims, further comprising a funnel arrangement (38) which is arranged to be attached to a connection (46) and to convey a product from the inside (10) of the compensator (1) to the connection (46).

14. Compensator according to claim 13, wherein the funnel assembly (38) has a first discharge line (38a) which is adapted to be attached to a first terminal (46), and wherein the funnel assembly (38) has a second discharge line (38b) which is adapted to be attached to a second terminal (47).

15. Compensator according to one of claims 13 or 14, wherein the funnel arrangement (38) comprises from the inside (10) to the outside (12) an inner layer (20), a first thermal insulation layer (24), a first film (26) and an outer layer (34).

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