EP0194293B1 - Wall element for dough product dryers - Google Patents

Abstract

In a dough product dryer (1) with an insulating jacket surrounding the dryer and whose side components consist of individual externally-convex wall elements (10) which can be clamped in their peripheral regions against frame sections (13) of the dryer, the wall elements (10) are convexely curved in the form of a cylinder section and the relevant frame sections (13) are correspondingly shaped to match.

Description

Technical field

The invention relates to a pasta dryer with an insulation casing comprising the dryer, the side parts of which consist of individual wall elements which are curved outwards and can be braced in their edge regions against frame parts of the dryer.

Underlying state of the art

A pasta dryer of the type specified above is known from the BÜHLER / BÜHLER-MIAG brochures TW 24032 D-1000-7801 BF and TW 24020 D 500 7810 BDO.

The insulation formwork of pasta dryers has to meet different requirements. On the one hand, this is to prevent significant energy from being released into the environment through the casing. A good insulation effect of a formwork also means that there are correspondingly large temperature differences between the innermost and outermost skin of the formwork, which leads to different thermal expansions on the formwork. In order to prevent air gaps from forming between the wall elements, it is known to cover their joints with sealing tapes. However, this solution can lead to the fact that, under extreme conditions, the wall elements can only be reattached after a long period of service work using additional sealing material. If, as is often the case today, flat panels are used for wall elements, the problem shown turns out to be even more unfavorable because the shape stability of these panels is lower.

In order to achieve better dimensional stability on the wall elements here, wall elements have already been used which have a slight curvature (large radius) in their central area and a greater curvature (smaller radius) at their edge areas (lower and upper end areas), which means that an improved dimensional stability could be achieved there - at least for a while (see the aforementioned BÜHLER / BÜHLER-MIAG brochures). With these wall elements, however, there is a risk that - not least also because of the different curvature of the wall elements - when larger temperature differences occur, there will be uneven stress distributions over the entire cross-section and thus the risk of cracks and leaks occurring in the area of mutual contact between the wall elements and the Frame parts is coming.

From DE-B-1 080 487 (BÜHLER) a pasta dryer with a casing comprising the dryer is also known, the side parts of which are curved outwards. With this pasta dryer, too, the edge areas, i.e. the lower and upper end regions of the side parts are more curved than the central region. For the rest, this document does not focus on individual wall elements, especially not on individually braceable wall elements but on a continuous side wall.

A pasta dryer is also known from DE-C-87 515 (BAERMANN), the casing of which is designed as an insulation casing. As with the aforementioned DE-B - 1 080 487 (BÜHLER), the side parts of the dryer are not designed as individual wall elements. Rather, the entire dryer is designed as a continuous closed chamber, which e.g. can have a cylindrical, elliptical, primitive or other overall shape.

Finally, it is known from DE-C-490 478 (RAK-KEBRANT) to shutter doors, slides or closures for drying systems or other ovens on the inside with individual sheet metal disks that overlap in a scale-like manner.

Disclosure of the invention

Proceeding from this, the object of the invention is to equip a pasta dryer with such insulation casing that, even when large temperature differences occur between the inside of the dryer and the surroundings of the dryer, the stress distribution is evened out over the entire cross-section and thus leads to a reduced risk of cracks and leaks occurring. In particular, however, it should also be possible to remove and reattach the wall elements quickly and as often as desired for carrying out service work.

According to the invention, this object is achieved in a pasta dryer of the type mentioned at the outset in that the wall elements are curved in the form of a cylindrical section with a constant radius of curvature and the associated frame parts are designed accordingly.

It has surprisingly been found that the measures according to the invention also lead to a surprisingly dimensionally stable behavior of the wall elements even when there is a strong change in temperature and with large temperature differences, and that the risk of undesirable crack formation could be clearly reduced as a result of a noticeable homogenization of the stress distribution over the surface of the wall elements. Compared to the previously known wall elements, which were provided with a greater curvature in their lower and upper edge regions for the purpose of dimensional stability than in the central region, the pasta dryer according to the invention also always provided a very good sealing of the wall elements on the associated frame parts, even then, if there were major temperature differences. Thus, the use of additional sealing tapes can be completely dispensed with here in the invention, which was virtually impossible with the known dryers and what there is also no need to replace the seals after performing service work. It has proven to be advantageous if the wall elements are provided with a uniform wall thickness over their entire surface.

In the invention, the wall elements are preferably connected as a vapor barrier on their side facing the inside of the dryer with a plate, again preferably made of thin metal sheet, loosely inserted into the arch shape. Depending on the operating mode, e.g. a 0.5 to 1 mm thick plate made of e.g. stainless steel sheet can be inserted without a rigid attachment on the inside of the respective wall element. In practice, such a sheet steel plate proves to be an effective vapor barrier whereby it easily and completely adapts itself to the curvature of the wall element when inserted, since it has a corresponding flexibility over its entire surface. This has the advantage that any special processing of the vapor barrier is omitted, since, as already mentioned, the metal sheet easily adapts to the curved shape of the inside of the wall element (it must be taken into account that these wall elements have a length and a radius of curvature of the order of magnitude 1 to 3 m). It is only necessary to ensure that a suitable holder for such a plate is provided as a vapor barrier on the inside of the wall element, but this is not a holder by which the steel sheet is rigidly attached to the wall element. Rather, such a holder is to be provided, in which the steel plate is only inserted and in which it can expand or contract when temperature differences occur: the holder only has to ensure that the inserted steel plate is held in sufficient shape, for example, on its outer circumference in relation to the wall element so that it cannot fall away from it again. In the invention, this can e.g. in a particularly advantageous manner in the form that such a wall element is provided on its entire outer circumference on its inside (ie the side of the wall element facing the interior of the dryer) with a profile seal, such as a rubber profile, which is arranged so that it supports the plate-shaped vapor barrier against the wall element. It is furthermore advantageous if the plate-shaped vapor barrier does not protrude laterally from such a profile seal, such as a rubber seal (ie that the rubber seal is arranged around the edge region of the wall element such that the plate-shaped vapor barrier is surrounded by the seal in its peripheral edge region with their lateral edges not protruding beyond the surface area enclosed by the seal). Since the vapor barrier is only inserted into the holder, but should not be rigidly connected to the wall element and therefore there is no fixed (rigid) connection between the vapor barrier and the wall element, the vapor barrier can also expand independently of the wall element under the influence of temperature without the occurrence of undesirable forced stresses or pull together and is still held sufficiently well by the profile seal against the wall element. The occurrence of undesirable constraint stresses can be almost completely avoided, which is a very important advantage over known designs.

A further advantageous embodiment of the invention consists in that the wall elements consist of foam or another insulation material which has a resistant outer skin, the outer skin of the wall element facing the dryer interior being provided with one or more grooves. The grooves, for example in the form of two to six fingers deeply distributed on the surface, not only result in a further consolidation of the shape of the wall element in question, but at the same time also enable a reduction in the length changes of the external dimensions that occur on the inside of the wall (for example due to higher temperatures) whereby it can be achieved that almost no undesirable thermal stresses occur. Since these grooves are completely covered by the vapor barrier (metal sheet), they do not create any dirt traps, which is also a quick and thorough process. Cleaning such a dryer allowed.

A further advantageous embodiment of the invention also consists in the fact that each wall element is suspended from hinges on its upper side and can be pressed against the corresponding frame parts by means of clamping elements arranged on its underside, it being particularly advantageous if hinges are each arranged directly (vertically) above clamping elements are. This allows a further practical practical handling when performing maintenance work. At the same time it is achieved that due to the weight of the respective outwardly curved wall element, it already fits well against the corresponding frame parts of the pasta dryer without additional force. By means of the tensioning elements it is possible to ensure a completely tight seal on the entire circumference of the vapor barrier (wall element) with only slight deformation of the sealing profile and thus even when there are slight manufacturing inaccuracies.

Each wall element is preferably assigned a support arm which is attached to the frame part and can be folded down. If cleaning or other service work is to be carried out, two or three quick-release fasteners can be opened quickly with just a few hand movements, the bottom wall element pulled away with one hand and the support arm holding it in an open position with the other hand into the desired position Position. In this way, downtimes can be significantly reduced compared to known solutions.

It is also advantageous if the wall elements are designed with the same wall thickness over their entire surface. Since a vapor barrier can be inserted on the inside, the wall elements can be selected in accordance with the other requirements in terms of their qualitative structure and the thickness of the insulation material, regardless of the vapor barrier.

Brief description of the drawings

• Figur 1 eine perspektivische Darstellung eines erfindungsgemäßen Teigwarentrockners;
• Figur 2 eine Innenansicht eines Wandelementes bei einem erfindungsgemäßen Teigwarentrockner;
• Figur 3 eine schematische Seitenansicht einer Isolationsverschalung bei einem erfindungsgemäßen Teigwarentrockner;
• Figur 4 den Schnitt IV-IV aus Figur 2, und
• Figur 5 den Schnitt V-V aus Figur 2.

The invention is explained in more detail below in principle by way of example with reference to the drawing. Show it:

• Figure 1 is a perspective view of a pasta dryer according to the invention;
• Figure 2 is an interior view of a wall element in a pasta dryer according to the invention;
• FIG. 3 shows a schematic side view of an insulation casing in a pasta dryer according to the invention;
• Figure 4 shows the section IV-IV of Figure 2, and
• 5 shows the section VV from Figure 2.

Detailed description of the drawings

The typical pasta dryer 1 shown in FIG. 1 has an open front end. Conveying means (not shown), such as bar transport systems, a belt or vibratory conveyor, etc., are to be arranged in its interior, but are not shown in the drawing for the sake of clarity. In Figure 1, only three superimposed conveyor floors are shown. An air distribution space 2 and 3 each extend over the entire length of the pasta dryer 1. On both sides of the same, an upper and a lower circulation space 5 and 6 are provided separated by an intermediate wall 4, the air movement being forced by a sufficient number of fans 7 . Heating cooling and other heating elements are also present, but are not shown in detail in FIG. 1.

The pasta dryer 1 is surrounded at the top and bottom by flat insulation plates 8 and 9 and laterally by bulging wall elements 10, the latter having an arcuate shape in the form of a cylindrical section (i.e. they are curved with a constant radius over the height). The wall elements 10 are fastened at the top by two hinges 11 to the frame parts 13 (a frame part 13 lying at the front, which is adapted to the curvature of the wall element 10, is only shown in broken lines in FIG. 1). On its underside, the wall elements 10 can be pressed sealingly against the frame parts 13 present there by two quick-action fasteners 12, so that each wall element that can be opened upwards like a door can also be easily pivoted outwards again after the quick-release fasteners 12 have been released. The frame elements 13 are all adapted to the corresponding shape of the wall elements 10. While this leads to a curvature of the frame part 13 there corresponding to the inner curvature of the wall element 10 in the frame parts 13 running from top to bottom, as shown in dash-dotted lines in FIG. 1, this means for the frame parts 13 located in the longitudinal direction of the dryer below that their end edges , to which the wall elements 10 are pressed at the bottom, have a shape adapted to the curvature at least over the edge surface.

By means of a pivotable support arm 14, which can be folded downward, the wall element 10 in question can be easily held in the open position, as shown in FIG. Cleaning, service and inspection work can then be carried out inside the pasta dryer 1 without hindrance. Subsequently, rapid reclosing is easily possible.

FIG. 2 shows a wall element 10 in a view from the inside of the dryer. A rubber profile seal 15 runs around the outside of the wall element along the outer edge of the inner surface and is held in place by means of a holding plate 16 (cf. FIGS. 4 and 5). Three horizontal grooves 17 (see FIG. 2) ensure that undesired thermal expansions between the inner skin 18 and the outer skin 19 (FIGS. 2 and 5) can be absorbed in wall panels of only a short extent. In addition to a wear-resistant outer skin 18 or 19 (for example formed from a wear-resistant synthetic resin outer layer), the wall element 10 has an insulating material 20 in its interior which, depending on the desired requirements, e.g. can be selected as a foam with glass fiber reinforcement or as another suitable effective insulating material.

Furthermore, a metal plate 21 is held by the sealing profile 15 and loosely inserted in a receptacle holder on the inner curvature of the wall element 10 (FIGS. 4 and 5), which serves as a vapor barrier and in particular also represents a shield against the temperature of the interior of the dryer. The metal plate 21, for example in the form of a thin, rust-free metal sheet, is inserted in a loose form, as is shown in detail in FIG. 4 or FIG. 5, whereby the graphic representation there is expressly referred to as essential: such as 4 and 5, the vapor barrier 21 is pressed in its outer region by the profile seal 15 against the outer skin 18 of the wall element 10 present there. The vapor barrier 21 extends between the seal 15 and the outer skin 18 and is pressed against the outer skin 18 by the seal 15, which in turn is carried by the holding bracket 16 fastened to the wall element 10. In this way, a sufficiently firm holder is achieved, which reliably prevents the plate-shaped vapor barrier 21 from this holder (which is all around the vapor barrier 21) is) could fall out. However, the plate-shaped vapor barrier 21 under the rubber seal 15 is not blocked against expansion or contraction caused by thermal stresses, i.e. it can expand or contract undisturbed in its longitudinal direction, i.e. parallel to the surface of the outer skin 18, despite the continuous pressing action of the rubber seal 15 . The metal plate 21 can thus expand or contract almost without hindrance as a result of this chosen loose holder, without this resulting in undesirable forced stresses in it. There is also no deviation in the shape of the curvature which it assumed when it was inserted into the holder and which corresponds to the internal curvature of the wall element 10. As long as the metal plate 21 is held in its outer edge area against slipping, it can no longer fall out of the circumferential fastening, even when the convertible element is open. In the embodiment shown, the metal plate 21 also does not protrude laterally from the rubber seal 15, ie towards the side of the rubber seal 15 which does not face the area of the metal plate 21 enclosed by the rubber seal 15: this effectively prevents an undesirable thermal bridge from reaching the outside could arise.

In FIG. 3, the reference symbol R is used to indicate that the curvature of the wall element has the same radius R (from, for example, 1 to 3 m) over its entire height. Even with large temperature differences of up to 100 ° C. or more, length changes occurring in the holding element can hardly change the size of this radius R, as a result of which the plate 21 is always kept in a completely sealed position via the hinges 11 and the quick-action fasteners 12.

The embodiment of a dryer shown in the figures has a surprisingly high dimensional stability both in the cold and in the hot state. The metal plate 21 has proven to be a completely perfect vapor barrier and there is almost no air loss even with slight air pressure inside the pasta dryer. The pasta dryer shown can be cleaned almost optimally and also has a particularly pleasing shape on the outside.

The invention also includes a method for simply and effectively lining the wall elements with a vapor barrier by loosely inserting a thin, vapor-impermeable sheet or other suitable thin, flexible, plate-shaped material into an edge holder attached to the inside of the wall element (with the effect that it is thin Vapor barrier adapts itself to the curvature of the holding element and can move freely within the holder even under the influence of temperature, although it is otherwise held well by the holder). This makes it possible for the first time to produce an edge element with an effective vapor barrier in a cost-effective, quick and simple manner and without the occurrence of undesirably large forced stresses at large temperature differences and the risk of crack formation.

Claims (10)

1. Pasta drier with, surrounding the drier (1), an insulation cladding (8, 9, 10) whose side parts comprise individual outward-arched wall elements (10) which can be deformed in their marginal zones against frame parts (13) of the drier, characterized in that the wall elements (10) are arched in the form of a cylinder section with constant radius of curvature (R) and the appropriate frame parts (13) are made correspondingly adapted.

2. Pasta drier according to Claim 1, characterized in that the wall elements (10) are clad at their side facing the inside of the drier with a sheet (21) inserted loose in their arched shape as a vapour barrier.

3. Pasta drier according to Claim 2, characterized in that the vapour barrier is made of a thin metal sheet.

4. Pasta drier according to one of Claims 1 to 3, characterized in that the wall elements (10) are made of foam or another insulating material (20) and a reistant outer skin, the outer skin facing the inside of the drier having one or more grooves (17).

5. Pasta drier according to one of Claims 2 to 4, characterized in that each wall element (10) is provided along its entire periphery on its inside with a rubber section (15) which at the same time constitutes a support for the vapour barrier (21).

6. Pasta drier according to Claim 5, characterized in that the vapour barrier (21) does not project laterally beyond the rubber section (15).

7. Pasta drier according to one of Claims 1 to 6, characterized in that each wall element (10) is hung at its top side from hinges (11) and can be pressed against the appropriate frame parts (13) by clamping elements (12) on its bottom side.

8. Pasta drier according to Claim 7, characterized in that the hinges (11) are in each case disposed essentially vertically above clamping elements (12).

9. Pasta drier according to one of Claims 1 to 8, characterized in that a supporting arm (14) which is fixed on the appropriate frame part (13) and can be flapped down is allocated to each wall element (10).

10. Pasta drier according to one of Claims 1 to 9, characterized in that the wall elements (10) are of uniform thickness over their entire surface.

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