Dryer

Abstract

To provide a dryer with a lower maintenance cost.SOLUTION: A dryer 1 that allows a drying object M to contact a pair of heat transfer rollers 2 each comprising a plurality of grooves 2G arranged on the outer circumferential surface thereof along the circumferential direction, and each rotating on an axis AX to dry the drying object M, and scrapes off the dried drying object M by a scraper 3 from the heat transfer rollers 2, which heat transfer rollers 2 each comprise a roller body 20 heated from inside and a plurality of groove constituents 22 each constituting the plurality of grooves 2G, is characterized in that the groove constituents 22 are detachably attached to the roller body 20.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a dryer for drying an object to be dried.

Background Art

[0002] There is known a dryer that dries an object to be dried by bringing the object to be dried into contact with a heat transfer roller that rotates around an axis. The objects to be dried include many types such as sludge, general waste, food, dyes, and polymer compounds. In order to improve the heat transfer efficiency of the heat transfer roller in this dryer, it has been proposed to form a number of grooves or protrusions along the circumferential direction on the surface of the heat transfer roller (see, for example, Patent Document 1, etc.). Further, there is also known a dryer that inputs sludge or general waste between a pair of heat transfer rollers to perform molding and drying simultaneously (see, for example, Patent Document 2, etc.). In the dryer of this Patent Document 2, in order to perform molding and drying simultaneously, a number of grooves along the circumferential direction are formed on the surface of the heat transfer roller. Whether it is the dryer described in Patent Document 1 or the dryer described in Patent Document 2, it includes a scraper whose tip is disposed close to the heat transfer roller. And the dried object adhered to the outer peripheral surface of the heat transfer roller is scraped off from the heat transfer roller by the scraper.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] As the material being dried is repeatedly scraped from the heat transfer rollers, the outer surface of the heat transfer rollers gradually wears down, albeit very slowly. In addition, in dryers using a pair of heat transfer rollers, as described in Patent Document 2, the outer surface of the heat transfer rollers may wear down or get damaged when the material being dried gets trapped between the pair of rollers. When a heat transfer roller wears down or gets damaged, it needs to be replaced. Also, in dryers that perform both molding and drying, as described in Patent Document 2, the heat transfer rollers may be replaced with ones that have different groove shapes in order to change the molded shape of the material being dried. However, the manufacturing cost of heat transfer rollers is high because the processing required to form the grooves is time-consuming. Furthermore, heat transfer rollers require a cylindrical section with sufficient wall thickness to maintain the necessary strength with the grooves formed, and two end plates that can support the cylindrical section, which increases material costs and makes replacement work time-consuming due to their large mass. As a result, there has been a problem of high maintenance costs for dryers.

[0005] In view of the above circumstances, the present invention aims to provide a dryer that reduces maintenance costs. [Means for solving the problem]

[0006] The dryer of the present invention, which solves the above problems, In a dryer in which a material to be dried is brought into contact with a heat transfer roller having multiple grooves along the circumferential direction on its outer surface and rotating around an axis, and the dried material is scraped off the heat transfer roller by a scraper, The heat transfer roller comprises a roller body that is heated from the inside and groove components that form the grooves. The groove structure is characterized in that it is detachably attached to the roller body.

[0007] According to the dryer of the present invention, the grooved components, which are prone to wear and damage, can be removed from the roller body and replaced on their own, thereby reducing the maintenance costs of the dryer.

[0008] Here, the heat transfer roller may support the material to be dried in the groove. The scraper may have its tip positioned close to the outer circumferential surface of the heat transfer roller. Alternatively, the scraper may have its tip facing the outer circumferential surface on which the material to be dried is supported. Furthermore, the scraper may have claws that enter into the groove. The groove structure may be annular when viewed from the axial direction. Alternatively, the groove structure may be cylindrical. Furthermore, the groove structure may be positioned so that the tips of the scrapers face each other.

[0009] In the dryer of the present invention, The groove structure may be formed of a plurality of divided parts that are stacked in the axial direction and can be separated from one another.

[0010] Since only the worn or damaged sections can be replaced, the maintenance costs of this dryer can be further reduced.

[0011] In the dryer of the present invention, The roller body and the groove structure may be connected so as not to rotate by a rod-shaped key.

[0012] By connecting them in a non-rotatable manner using the aforementioned key, the roller body and the groove structure can be made to rotate in the same direction.

[0013] Furthermore, in the dryer of the present invention, The groove structure may have a slit that allows the groove structure to be opened in the circumferential direction.

[0014] By opening the groove structure in the circumferential direction, it becomes easier to remove the groove structure from the roller body.

[0015] Furthermore, in the dryer of the present invention, The groove structure may be formed in connection with the cut and may have a notch for inserting an instrument that opens the groove structure in the circumferential direction.

[0016] Even if the groove structure is baked onto the roller body, the groove structure can be opened in the circumferential direction by inserting the tool into the notch, so that the groove structure can be removed from the roller body.

[0017] In the dryer of the present invention, The notch may be formed in such a manner that the tool can be inserted from at least one end surface of the groove structure in the axial direction.

[0018] According to this aspect, the tool can be easily inserted.

[0019] Here, the notch may be formed such that the tool can be inserted from both end surfaces of the groove structure in the axial direction. By doing so, the tool can be inserted from either of the both end surfaces in the axial direction.

[0020] Also, in the dryer of the present invention, The groove structure may have a fitting portion into which a rod-shaped key for connecting the groove structure to the roller body fits, and a cut formed at a position overlapping with the fitting portion in the circumferential direction to enable the groove structure to be opened in the circumferential direction.

[0021] By doing so, even in a state where the key is fitted, the groove structure can be opened in the circumferential direction.

Effect of the Invention

[0022] According to the dryer of the present invention, it is possible to provide a dryer with reduced maintenance costs.

Brief Description of the Drawings

[0023] [Figure 1] It is a schematic view showing a dryer corresponding to an embodiment of the present invention. [Figure 2] It is a cross-sectional view showing the heat transfer roller of the dryer shown in FIG. 1. [Figure 3] This is a cross-sectional view AA in Figure 2. [Figure 4] This is a detailed view of section B in Figure 2. [Figure 5] This is a view of the divided heat transfer roller shown in Figure 2, from the right side in Figure 2. [Figure 6] Figure 5 is a cross-sectional view of CC. [Figure 7] Figure 2 is a flowchart showing the process of replacing the groove components in the heat transfer roller. [Figure 8] This is a detailed view similar to Figure 4, which shows an example where adjacent segments are attached in different orientations. [Figure 9] This is a view of the divided body in the dryer of the first modified example, seen from the right side in Figure 2. [Figure 10] This is a cross-sectional view similar to Figure 2, showing the heat transfer rollers in a dryer of the second modified example. [Figure 11] This is a detailed view similar to Figure 4, showing the groove structure in the dryer of the third modified example. [Modes for carrying out the invention]

[0024] Embodiments of the present invention will be described below with reference to the drawings. In this description of the embodiment, a dryer that molds and dries sludge such as organic sludge or inorganic sludge as the material to be dried to obtain a molded dried product will be used as an example.

[0025] Figure 1 is a schematic diagram showing a dryer corresponding to one embodiment of the present invention.

[0026] As shown in Figure 1, the dryer 1 has a pair of heat transfer rollers 2, two scrapers 3, a hopper 4, and a steam pressure regulating valve 5. The dryer 1 is supplied with materials M whose moisture content has been adjusted to some extent by mixing materials with high moisture content and materials with lower moisture content than the high moisture content.

[0027] Each heat transfer roller 2 is equipped with a pipe-shaped rotating support shaft 21 at both ends in the direction of the axis AX. The heat transfer roller 2 is rotatably supported around the axis AX by its rotating support shaft 21. One of the pair of heat transfer rollers 2 is driven by a motor (not shown) and rotates around the axis AX. This motor is capable of arbitrarily adjusting its rotational speed. The other heat transfer roller 2 receives driving force from the other heat transfer roller 2 and rotates at the same rotational speed and peripheral velocity as the other heat transfer roller 2. In Figure 1, the rotational direction of each heat transfer roller 2 is indicated by white arrows. These heat transfer rollers 2 are arranged so that their axes AX are parallel to each other. Also, a point on the outer surface of these heat transfer rollers 2 is positioned close to each other. Multiple grooves 2G (see Figure 2) are formed on the outer surface of each heat transfer roller 2 along the circumferential direction. The grooves 2G of the two heat transfer rollers 2 are positioned alternately in the axial direction AX, and in the parts where the heat transfer rollers 2 are close together, the opening of the groove 2G is closed by the outer surface of the other roller, forming a rectangular space. As the pair of heat transfer rollers 2 rotate, the material to be dried is pushed into this space, filling the groove 2G and being supported by the groove 2G. Since one heat transfer roller 2 and the other heat transfer roller 2 have the same shape except for the position of the groove 2G, in the following explanation, one heat transfer roller 2 will be described, and the explanation of the other heat transfer roller 2 may be omitted.

[0028] The rotating support shaft 21 is connected to a rotary joint (not shown). Steam is supplied to the rotary joint at one end. This steam is saturated steam, but may also be superheated steam. This steam is supplied to the heat transfer roller 2 via the inside of the rotating support shaft 21 at one end, heating the heat transfer roller 2. After heating the heat transfer roller 2, the steam becomes condensate and is discharged to the outside of the dryer 1 via the rotating support shaft 21 and rotary joint at the other end.

[0029] The two scrapers 3 are positioned opposite each other, with their tips close to each heat transfer roller 2. The scrapers 3 are also provided with an adjustment mechanism (not shown) for adjusting the tip position. The scrapers 3 have a comb-like shape with multiple claws. The number of claws is the same as the number of grooves 2G (see Figure 2) in the heat transfer roller 2, and each claw fits into its respective groove 2G.

[0030] The hopper 4 is positioned above the pair of heat transfer rollers 2. The hopper 4 has openings at the top and bottom. The material to be dried M is fed into the hopper 4 through the top opening and stored inside the hopper 4. The stored material to be dried M is supplied from the bottom opening of the hopper 4 to the upper part between the pair of heat transfer rollers 2.

[0031] The steam pressure regulating valve 5 is an automatic valve for adjusting the pressure of the steam supplied to each heat transfer roller 2 via the rotary joint and rotating support shaft 21 described above. The steam that has passed through the steam pressure regulating valve 5 is supplied to each heat transfer roller 2. By increasing the opening of the steam pressure regulating valve 5, the steam pressure supplied to the heat transfer roller 2 increases, and as a result the amount of heat transferred roller 2 heated increases.

[0032] As the heat transfer roller 2 rotates in the direction of the white arrow shown in Figure 1, the material to be dried M stored in the hopper 4 is sequentially pressed into the grooves 2G of the heat transfer roller 2 (see Figure 2). The pressed material to be dried M is then shaped by these grooves 2G and dried as heat is transferred from the parts in contact with the heated heat transfer roller 2, resulting in a dried material. The dried material is shaped into a cross-sectional shape corresponding to the shape of the grooves 2G. As the heat transfer roller 2 rotates, the dried material that reaches the scraper 3 is scraped off the heat transfer roller 2 by the scraper 3 and naturally breaks off and falls after a certain length. In other words, the dried material is scraped off by the claws of the scraper 3 that have entered the grooves 2G. If the material to be dried M is sludge, the length will be approximately 10 mm. However, this length varies depending on the properties of the material to be dried M and tends to fluctuate depending on the moisture content in the dried state. That is, if the moisture content of the dried material is low, it will be longer, and if the moisture content of the dried material is high, it will be shorter. The fallen dried material is discharged into a cushion hopper (not shown).

[0033] Figure 2 is a cross-sectional view showing the heat transfer roller of the dryer shown in Figure 1. In Figure 2, the hatching indicating the cross-section is omitted. Figure 2 shows a cross-section obtained by cutting the heat transfer roller 2 along the axis AX, and shows a cross-section including the key 25 which will be described later.

[0034] The heat transfer roller 2 comprises a roller body 20, a rotating support shaft 21 (see Figure 1), a groove structure 22, a pair of end plates 23, a fixing ring 24, and a key 25. Note that the rotating support shaft 21 is omitted from the illustration in Figure 2. The roller body 20 is cylindrical. One end of the roller body 20 is formed to be thicker than the other end, and a radially protruding projection 20a is formed on that end. Steam passing through the steam pressure regulating valve 5 (see Figure 1) is sent into a space S formed inside the roller body 20, heating the roller body 20 from the inside. The groove structure 22 is detachably attached to the roller body 20. The groove structure 22 constitutes the groove 2G. The groove structure 22 is formed by a plurality of divided parts 221 that are stacked in the axial direction AX. In Figure 2, an example is shown in which the groove structure 22 is formed by 92 segments 221, but the number of segments 221 can be arbitrary. When the roller body 20 is heated, heat is transferred from the heated roller body 20 and the groove structure 22 is also heated. The groove structure 22 will be described in detail later.

[0035] The end plates 23 are fixed to both ends of the roller body 20 by welding. A rotating support shaft 21 (see Figure 1) is attached to these end plates 23, thereby closing off both ends of the roller body 20 in the axial direction AX, except for the steam passage. The fixing ring 24 is fixed by being pressed toward one end by a retaining plate (not shown) that is screwed to the other end of the end plate 23. This fixing ring 24 holds the groove structure 22 in place so that it does not move in the axial direction AX by sandwiching the groove structure 22 between itself and the protruding portion 20a of the roller body 20. The key 25 is rod-shaped and has the same length as the length of the groove structure 22 in the axial direction AX.

[0036] Figure 3 is a cross-sectional view of AA in Figure 2. Note that in Figure 3, only the cross-sectional portion is shown, and the background is omitted. Also, the hatching indicating the cross-section of the groove structure 22 is omitted.

[0037] As shown in Figure 3, both the roller body 20 and the groove structure 22 are cylindrical in shape with an axis AX. Therefore, when viewed from the direction of axis AX, the roller body 20 and the groove structure 22 are annular in shape. Also, the circumferential direction of the roller body 20 and the groove structure 22 (divided parts 221) is the circumferential direction of the heat transfer roller 2. The inner diameter of the groove structure 22 is slightly larger than the outer diameter of the roller body 20. The groove structure 22 is fitted onto the outer circumferential surface of the roller body 20. An axial key groove 20b is formed on the outer circumferential surface of the roller body 20. In addition, a hole key groove 221a is formed on the inner circumferential surface of each of the multiple divided parts 221 that make up the groove structure 22. This hole key groove 221a corresponds to an example of a fitted portion. The roller body 20 and the groove structure 22 are connected to each other so as not to rotate in the circumferential direction by a prismatic key 25 fitted into the axial key groove 20b and the hole key groove 221a. Therefore, when the roller body 20 is rotated, the groove structure 22 rotates together with the roller body 20 in the same direction and at the same rotational speed.

[0038] Figure 4 is a detailed view of section B in Figure 2.

[0039] As shown in Figure 4, each segment 221 constituting the groove structure 22 is stacked on the outer surface of the roller body 20 in the thickness direction of the segment 221, forming a so-called stacked state. Each segment 221 is separable from one another. Therefore, by removing the fixing ring 24 from the roller body 20, the segments 221 can be individually removed from the roller body 20, starting from the other end. The thickness direction of the segment 221 coincides with the direction of the axis AX (see Figure 2). A recess is formed on the outer portion of each segment 221, which becomes the groove 2G on the outer surface of the heat transfer roller 2. Since this recess is formed in a rectangular shape at the corner of the outer circumference of the segment 221, the segment 221 in this embodiment has an L-shaped cross-section. Note that the cross-section of the segment 221 is shown as an inverted L-shape in Figure 4. By providing a recess in each segment 221, the heat transfer roller 2 has the same number of grooves 2G as the segment 221. The recess may be formed in the central part of the thickness direction of the divided body 221 so as to be a concave shape in cross-section, but it is preferable to form it in the corner part of the outer circumference of the divided body 221 so as to be L-shaped in cross-section, as described above, for ease of machining. If a recess with a generally rectangular cross-section is formed in the corner part of the outer circumference of the divided body 221, as in the present embodiment, the machining process for forming the recess is particularly easy. The scraper 3 shown in Figure 1 has a length (width) in the axial direction AX that is roughly the same as that of the groove structure 22, and its tip is positioned opposite the groove structure 22. That is, the position and length of the scraper 3 and the groove structure 22 are almost the same in the axial direction AX. Furthermore, the tip of the scraper 3 is positioned close to and opposite the outer circumferential surface of the heat transfer roller 2 formed by the groove structure 22.

[0040] Figure 5 is a view of the divided heat transfer roller shown in Figure 2, seen from the right side in Figure 2. Figure 6 is a cross-sectional view of the CC section of Figure 5.

[0041] As shown in Figures 5 and 6, each segmented body 221 has a notch 221c and a slit 221d formed at one location around its circumference. The notch 221c is connected to the keyway 221a and is formed extending outward from the keyway 221a. The slit 221d is connected to the notch 221c and is formed further outward from the notch 221c. Therefore, the keyway 221a and the slit 221d are formed at overlapping positions in the circumferential direction of the segmented body 221. The presence of the slit 221d allows the groove structure 22 (segmented body 221) to open in the direction of separation of the slit 221d (left-right direction in Figure 5), but when no load is applied to spread it in the direction of separation, the slit 221d is closed and the circumferential end faces are in contact. Conversely, by pushing the divided body 221 apart in the separating direction, the circumferential end faces of the divided body 221 separate at the cut 221d and open in the circumferential direction. If the divided body 221 is pushed apart within the range of elastic deformation, the cut 221d will close again when this separating force is released.

[0042] With the divided body 221 attached to the roller body 20, the cut 221d can be separated and the divided body 221 can be opened in the circumferential direction by inserting a wedge into the notch 221c or by inserting the tip of a flathead screwdriver or the like into the notch 221c and twisting the screwdriver. These wedges and flathead screwdrivers are examples of tools. The notch 221c is formed in the divided body 221 and penetrates in the direction of the axis AX. Therefore, a wedge and a flathead screwdriver can be inserted from either end face of the divided body 221 in the direction of the axis AX. However, the notch 221c may be formed only from the end face of the divided body 221 in the direction of the axis AX to partway along the thickness direction of the divided body 221. In that case, it is preferable to form the notch 221c so that a wedge or a flathead screwdriver can be inserted from at least the other end face of the groove structure 22 in the direction of the axis AX. However, it is more preferable to form notches 221c on each end face of the segmented body 221 in the axial direction AX so that a wedge and a flathead screwdriver can be inserted from either end face of the grooved body 22 in the axial direction AX. Even if the segmented body 221 is stuck to the roller body 20 and cannot be easily removed from the roller body 20, the grooved body 22 (each segmented body 221) can be opened in the circumferential direction by inserting a wedge or a flathead screwdriver into the notches 221c, thereby allowing the grooved body 22 to be removed from the roller body 20.

[0043] Furthermore, if the hole keyway 221a and the slit 221d are far apart in the circumferential direction of the divided body 221, the key 25 (see Figure 2) will get in the way when trying to open the divided body 221 in the circumferential direction, making it difficult to open the divided body 221. By forming the hole keyway 221a and the slit 221d in overlapping positions in the circumferential direction of the divided body 221, the divided body 221 can be opened in the circumferential direction without the key 25 getting in the way.

[0044] Figure 7 is a flowchart showing the process of replacing the groove structure in the heat transfer roller shown in Figure 2.

[0045] As shown in Figure 7, in the process of replacing the groove assembly 22, first, the screws of the retaining plate (not shown) that secures the fixing ring 24 are removed and the fixing ring 24 is removed from the roller body 20 (step S11). Next, a wedge is inserted into the notch 221c of the division 221 at the far end of the multiple divisions 221 stacked in the axial direction AX, or a flathead screwdriver is inserted into the notch 221c and the screwdriver is twisted (step S12). However, this step S12 is performed to make it easier to remove the division 221 when it is difficult to remove the division 221 from the roller body 20, such as when the division 221 is stuck to the roller body 20. Therefore, if the division 221 can be easily removed from the roller body 20 without performing this step, step S12 may be omitted. Then, the division 221 at the far end of the multiple divisions 221 is removed from the roller body 20 (step S13). Next, it is determined whether or not all of the divided parts 221 to be replaced have been removed (step S14). If not, steps S12 to S14 are repeated until the removal is complete, and the divided parts 221 are removed in order, starting from the other end.

[0046] Once all the segments 221 to be replaced have been removed (YES in step S14), the new segments 221 or segments 221 that do not need to be replaced are attached to the roller body 20 (step S15). Next, it is determined whether or not all segments 221 have been attached (step S16). If not (NO in step S16), steps S15 to S16 are repeated until all segments 221 are attached. Once all segments 221 have been attached (YES in step S16), the fixing ring 24 is attached to the roller body 20 (step S17). This completes the process of replacing the groove components 22.

[0047] As described above, with the dryer 1, groove components 22 that have become difficult to obtain dried products molded into the desired shape due to wear or damage can be removed from the roller body 20 and replaced with normal groove components 22, making them inexpensive replacement parts and reducing the maintenance costs of the dryer 1. In addition, since it is not necessary to replace all of the large heat transfer rollers 2, the replacement work becomes easier. Furthermore, since the groove component 22 is composed of multiple divided parts 221, only the divided parts 221 that are worn or damaged can be replaced. This further reduces the maintenance costs of the dryer 1. Moreover, since the groove component 22 can be replaced by replacing the divided parts 221 which have relatively little mass, the replacement work becomes even easier.

[0048] Figure 8 is a detailed view similar to Figure 4, showing an example where adjacent segments are attached in different orientations. Note that in Figure 8, the hatching indicating the cross-section is omitted.

[0049] In the drying oven 1, which performs molding and drying, the shape of the groove 2G of the heat transfer roller 2 may be changed to alter the molded shape. As in this embodiment, the groove structure 22 is composed of multiple divided parts 221, and the width of the groove 2G can be changed by forming indentations in the divided parts 221 at the corners of the outer circumference of the divided parts 221, as shown in Figure 8. In the heat transfer roller 2 of Figure 8, the width of the groove 2G is doubled by attaching adjacent divided parts 221 to the roller body 20 in opposite directions. When the configuration of the combination of divided parts 221 is changed in this way, a scraper of a corresponding shape will be used.

[0050] Next, we will describe the modified dryer 1. In the following description, the same symbols used previously may be used for the names of components that have already been described, and redundant explanations may be omitted.

[0051] Figure 9 shows the divided body in the dryer of the first modified example, viewed from the right side in Figure 2.

[0052] As shown in Figure 9, the divided body 221 of the first modified example differs from the previous embodiment in that a groove 221e is formed on the outer circumference of the cut 221d, and the outer circumference of the cut 221d is joined by welding. In Figure 9, the filler material is shown as a dot pattern. In this first modified example of the dryer 1, if the divided body 221 cannot be easily removed from the roller body 20 when removing the divided body 221 from the roller body 20, the welded portion is scraped off before step S12. This causes the divided body 221 to open in the circumferential direction, and by opening it, the grooved body 22 can be easily removed from the roller body 20.

[0053] This first modified dryer 1 also produces the same effects as the previous embodiment. In addition, the first modified dryer 1 has the effect of preventing the cuts 221d of the divided body 221 from unintentionally separating in the direction of separation, and preventing the cuts 221d from shifting radially and creating steps.

[0054] Figure 10 is a cross-sectional view similar to Figure 2, showing the heat transfer rollers in a second modified dryer. Note that in Figure 10 as well, the hatching indicating the cross-section has been omitted.

[0055] As shown in Figure 10, the heat transfer roller 2 of the second modified example differs from the previous embodiment in that the groove structure 22 is formed integrally, rather than being made of stacked divided bodies 221. The cross-sectional view of the groove structure 22 of this second modified example is identical to the cross-sectional view of the divided body 221 shown in Figure 5, except that the reference numeral 221 is changed to 22, so it will not be described here, but will be explained with reference to Figure 5. The cut 221d in the groove structure 22 of the second modified example is formed continuously along the entire length of the groove structure 22 in the axial direction AX. When the groove structure 22 is pushed apart, the groove structure 22 separates at the cut 221d portion and opens in the circumferential direction.

[0056] The notch 221c is also formed continuously along the entire length of the groove structure 22 in the axial direction AX. The notch 221c and the cut 221d are formed in connection. However, the notch 221c may be interrupted in the axial direction AX, as long as it is formed so that the end face of the groove structure 22 in the axial direction AX is open. In that case, it is preferable to form the notch 221c so that a wedge or a flathead screwdriver can be inserted from at least the other end face of the groove structure 22 in the axial direction AX. However, it is more preferable that the notch 221c is formed on both end faces of the groove structure 22 in the axial direction AX so that a wedge and a flathead screwdriver can be inserted from either of the end faces of the groove structure 22 in the axial direction AX. Even if the groove component 22 is seized to the roller body 20 and cannot be easily removed from the roller body 20, the groove component 22 can be easily removed from the roller body 20 by inserting a wedge or a flathead screwdriver into the notch 221c to open the groove component 22 in the circumferential direction.

[0057] The hole keyway 221a is connected to the notch 221c. Furthermore, the hole keyway 221a and the notch 221d are formed continuously along the entire length in the axial direction AX at overlapping positions in the circumferential direction of the groove structure 22. By forming the hole keyway 221a and the notch 221d at overlapping positions in the circumferential direction of the groove structure 22, the groove structure 22 can be opened in the circumferential direction without the key 25 getting in the way.

[0058] This second modified dryer 1 also produces the same effects as the previous embodiment. However, if the groove structure 22 becomes worn or damaged, it is necessary to replace the groove structure 22 as a whole. Also, it is not possible to change the groove width of the heat transfer roller 2 as explained using Figure 8.

[0059] Figure 11 is a detailed view similar to Figure 4, showing the groove structure in the third modified dryer. Note that in Figure 11 as well, the hatching indicating the cross-section has been omitted.

[0060] As shown in Figure 11, the groove structure 22 of the third modified example differs from the previous embodiment in that it is composed of a large-diameter segment 222 and a small-diameter segment 223. The large-diameter segment 222 and the small-diameter segment 223 have the same inner diameter but different outer diameters. The groove 2G of the heat transfer roller 2 is formed by the difference in these outer diameters. In other words, the groove 2G of the heat transfer roller 2 is mainly defined by the outer circumferential surface of the small-diameter segment 223 and the side surface of the large-diameter segment 222.

[0061] This third modified dryer 1 also achieves the same effects as the previous embodiment. Furthermore, since large-diameter segments 222 and small-diameter segments 223 can be made by slicing cylindrical members with the same inner diameter but different outer diameters (wall thicknesses), the groove structure 22 can be manufactured at low cost. In addition, although Figure 11 shows an example in which the large-diameter segments 222 and small-diameter segments 223 are arranged adjacent to each other, the width of the groove 2G can be multiplied by several times by arranging multiple small-diameter segments 223 in a row. Furthermore, the width of the groove 2G can be arbitrarily adjusted by preparing small-diameter segments 223 of different types with different thicknesses (widths) in the axial direction AX. Moreover, the depth of the groove 2G can be arbitrarily adjusted by preparing small-diameter segments 223 of different types with different outer diameters (wall thicknesses).

[0062] The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims. For example, although this embodiment describes a dryer 1 that obtains a dried product formed by a pair of heat transfer rollers 2, the present invention may also be applied to a dryer 1 that simply dries the product to be dried M with a pair of heat transfer rollers 2 without forming. Alternatively, the present invention may be applied to a dryer 1 that dries the product to be dried M with a single heat transfer roller 2, as in Patent Document 1. In addition, when the groove structure 22 is constructed by stacking a plurality of divided bodies 221 divided in the axial direction AX, the number of divisions may be any number. Furthermore, the grooves 2G of the groove structure 22 may have cross-sectional shapes other than rectangular, such as dovetail grooves, arc shapes, U-shapes, or V-shapes. Also, although the roller body 20 was heated by steam, it may be heated by other fluids such as liquids, or it may be heated by a heater placed inside. Furthermore, instead of providing a protrusion 20a on the roller body 20, fixing rings 24 may be attached to both ends of the roller body 20 in the direction of the axis AX, and the groove structure 22 may be held in place by sandwiching it between the two fixing rings 24 so that it does not move in the direction of the axis AX.

[0063] Furthermore, even if a constituent element is included only in the description of each of the modified examples described above, that constituent element may be applied to other modified examples as well. [Explanation of Symbols]

[0064] 1 Dryer 2 Heat transfer rollers 3. Scraper 20 Roller body 22 Groove structure 2G groove AX axis M Material to be dried

Claims

1. In a dryer in which a material to be dried is brought into contact with a heat transfer roller having multiple grooves along the circumferential direction on its outer surface and rotating around an axis, and the dried material is scraped off the heat transfer roller by a scraper, The heat transfer roller comprises a roller body that is heated from the inside and groove components that form the grooves. The groove structure is detachably attached to the roller body, A dryer characterized in that the roller body and the groove structure are non-rotatably connected by a rod-shaped key.

2. A dryer in which a material to be dried is dried by bringing it into contact with a heat transfer roller having a plurality of grooves along the circumferential direction on its outer surface and rotating around an axis, and the dried material is scraped off the heat transfer roller by a scraper, The heat transfer roller comprises a roller body that is heated from the inside and groove components that form the grooves. The dryer is characterized in that the groove structure is detachably attached to the roller body and has a slit that allows the groove structure to be opened in the circumferential direction.

3. The dryer according to claim 2, characterized in that the groove structure is formed in connection with the cut and has a notch for inserting an instrument that opens the groove structure in the circumferential direction.

4. The dryer according to claim 3, characterized in that the notch is formed so that the instrument can be inserted from at least one end face of the groove structure in the axial direction.

5. A dryer in which a material to be dried is dried by bringing it into contact with a heat transfer roller having a plurality of grooves along the circumferential direction on its outer surface and rotating around an axis, and the dried material is scraped off the heat transfer roller by a scraper, The heat transfer roller comprises a roller body that is heated from the inside and groove components that form the grooves. The dryer is characterized in that the groove structure is detachably attached to the roller body and has a fitted portion into which a rod-shaped key for connecting the groove structure to the roller body is fitted, and a slit formed at a position overlapping with the fitted portion in the circumferential direction, which allows the groove structure to be opened in the circumferential direction.

6. The dryer according to any one of claims 1 to 5, characterized in that the groove structure is formed of a plurality of divided parts that are stacked in the axial direction and can be separated from each other.

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