DK178883B1

DK178883B1 - Feeding arrangement comprising an agitator

Info

Publication number: DK178883B1
Application number: DKPA201570526A
Authority: DK
Inventors: Christer Friggeråker
Original assignee: Friggeråkers Verkstäder Ab
Priority date: 2014-08-19
Filing date: 2015-08-13
Publication date: 2017-04-24
Also published as: NO20151024A1; NO346235B1; DK201570526A1; SE538833C2; SE1450962A1

Abstract

The present invention relates to a feeding arrangement (1) for road salt distribution comprising a container (2) and at least one feeding screw (4), arranged to feed salt in the container (2). The feeding arrangement (1) further comprises at least one agitator (10) comprising a rotatable shaft (12) and a plurality of plates (14), wherein the plates (14) are angularly arranged on the rotatable shaft (12), so that when the rotatable shaft (12) is rotated around its central axis, the plates (14) move round the rotatable shaft (12) and shovel the salt in the container (2).

Description

FEEDING ARRANGEMENT COMPRISING AN AGITATOR Technical field

The present invention relates to a feeding arrangement for a salt spreader, in particular a salt spreader for road maintenance connected to a vehicle.

Background EP 0837188 A1 describes a winter service spreading device for spreading gravel and comprising a container with a transport channel. In the transport channel an endless screw conveyor is arranged. The device further comprises an agitator with a rotatable shaft arranged parallel to the screw conveyor. The rotatable shaft has a plurality of V-shaped stirring elements angularly arranged on the shaft.

In the field of road maintenance, the use of salt spreading vehicles is common. Commonly, the salt is spread in the winter in order to avoid slippery roads because of ice and hard packed snow. The salt may also be spread during spring and summer in order to reduce dustiness on gravel roads. In preparation for spreading the salt, the salt is commonly loaded in a container associated with the salt spreading vehicle. In order to spread the salt onto the road, the salt needs to exit the container. Commonly the salt is fed through the container using feeding screw(s), also named screw conveyor.

Depending on properties of the salt, it may behave differently when fed in the container, for instance depending on its moisture level. Especially finegrained salt (such as vacuum salt), which may have a moisture level of about 4 %, may cause problems in the container when being fed by a feeding screw. Such salt may form lumps or blocks that prevent the salt from being fed by the feeding screw in the desired way. The salt may then be packed in the container, clogging the feeding screw, and avoid being fed to exit the container. Further, arches, walls or bridges of salt may be formed next to the feeding screw that prevents that salt from being fed to exit the container.

It is known to provide two or more feeding screws next to each other, or to form the container walls, to try to avoid this problem. However, no such solutions have been provided that sufficiently solves the problem.

Consequently, there is a need for a solution that may prevent the forming of lumps and blocks of the salt when being fed by a feeding screw, and that may prevent the salt from forming arches or bridges next to the feeding screw.

Summary

It is an object of the present invention to provide an improved solution that alleviates the mentioned drawbacks with present devices. Furthermore it is an object to provide a salt feeding arrangement with a more reliable operation.

The invention is defined by the appended independent claims. Embodiments are set forth in the dependent claims, in the following description and in the drawings.

The invention is based on the inventor’s realization that by providing a salt feeding arrangement having an agitator running next to a feeding screw, the amount of lumps or blocks of the salt will decrease, the forming of arches and bridges of the salt is prevented, and the risk of clogging is reduced.

According to an aspect of the invention a feeding arrangement for road salt distribution is provided comprising a container and at least one feeding screw, arranged for feeding salt in the container. The feeding arrangement further comprises at least one agitator comprising a rotatable shaft and a plurality of plates, wherein the plates are angularly arranged on the rotatable shaft, so that when the rotatable shaft is rotated around its central axis, the plates move round the rotatable shaft and shovel the salt in the container and wherein the agitator is arranged parallel to the feeding screw, and the feeding arrangement further comprises at least one divider element arranged between the feeding screw and the agitator to avoid collision of the feeding screw and the agitator.

To provide a feeding arrangement according to this, salt may be fed through a container that may be horizontal. The feeding screw may allow the salt to be transported horizontally, and the agitator may ensure that the salt remains without lumps or blocks. Also, by having an agitator, the salt may constantly be shoveled so that it is avoided for the salt to stick to the container walls, and thereby form a dense block of salt that does not enter the feeding screw. The salt may be of any concentration suitable. It may be of any grain size. It may be dry salt, or contain a mixture of salt and other substances. The feeding arrangement may further be suitable for feeding any other granular material that may suffer from a similar problem.

The agitator may be a long shaft with plates distributed along the shaft. It may be as long as the length of the container and may be arranged at the bottom of the container. The agitator and the feeding screw may be arranged horizontally along the container. The plates may be evenly distributed or arranged at random. The plates may be arranged at an angle from the rotatable shaft. This may provide effective agitation since the plates upon rotation shovel the salt and thereby prevents the salt being packed and stick to the container walls.

In order to provide good agitation throughout the length of the container, the feeding screw and the agitator may be arranged parallel to each other. By doing so, the agitation and the feeding may take place simultaneously and the risk that any salt that may be stuck to the container wall due to the force of the feeding screw may be reduced. However, it is possible that it may be suitable to have the agitator arranged differently relative to the feeding screw, for instance angularly or crossed.

In order to ensure that the feeding screw and the agitator do not collide, the arrangement may be provided with a divider element. Collision may be possible since the feeding screw and the agitator may be long shafts, and since the movement of the two, resonance of the shafts may occur, and thereby the two shafts may be at risk at colliding. The divider element, or elements, may thus be arranged in the bottom of the container to decrease the risk of collision, at predetermined distances between the feeding screw and the agitator. The divider elements may be of a length similar or almost of a length that equals the distance between two plates. There may be a number of elements placed at predetermined places along the container bottom. The divider elements may be rectangular plates arranged at the bottom of the container. Alternatively, they may be shaped and sized to suit the particular installation. The divider elements may be round, square or a pillar and may be shaped as blocks or any other suitable geometric shape.

According to one embodiment, the plates may have an elliptical shape. The plates may be of an elliptical shape so that when mounted on the rotatable shaft, the large radius of the plate may be extended along the rotatable shaft. The plates may be elliptical such that, when arranged with an angle to the rotatable shaft, the rotating elliptical plates provides substantially circular radial edges when seen in an axial cross-section. This may upon rotation allow the agitator to be arranged close to the bottom of the container and evenly shovel the salt close to the container bottom. The plates may however be of any size or other geometric shape that may seem suitable.

According to one embodiment of the invention, the plates may be arranged so that the centre of the plates coincides with the central axis of the rotatable shaft.

By arranging the plates symmetrically around the rotatable shaft, the plates may evenly shovel the content in the container bottom. It may prevent any sharp edges to cause noise as the plates may hit the container wall if not properly arranged.

According to one embodiment of the invention, the plates may be arranged parallel to each other.

The plates may be arranged spaced apart and parallel. By letting the plates be placed parallel, the pattern may be predetermined and may hence be allowed to cooperate with the feeding screw without the risk of colliding with the feeding screw. Alternatively, the plates may be arranged at random, or at any space at different angles according to a pattern.

According to one embodiment of the invention, the plates may be arranged at an angle relative to the rotatable shaft of about 25-65 degrees, preferably about 45 degrees.

By arranging the plates angularly, a larger amount of the content in the container may be shoveled. The angle may be large enough to efficiently shovel the salt in the container. A too large angle may cause the salt not to be shoveled enough to provide an efficient agitation.

According to one embodiment of the invention, at least two of the plates may be arranged at a distance (A) from each other along the rotatable shaft such that the distance (A) is determined by: A < d cos a, wherein d is the diameter of the plates and a is the angle of the plates relative to the rotatable shaft.

The distance between the plates may be determined so that any point, or nearly any point, along the length of the rotatable shaft may have a plate arranged. This may be so that the salt in the container may be properly agitated, and that as much salt as possible is shoveled to prevent the salt from lumping. In case there should be a gap between plates, a hard wall of salt may be formed perpendicular to the shaft which may prevent salt from being fed through the feeding screw.

According to one embodiment of the invention, at least one plate of the agitator may be peripherally displaced relative to another plate.

By providing a peripheral displacement, or turning, of a plate relative to another plate, special agitation effects may be achieved. For instance, displaced plates may affect the feeding functionality of the feeding screw by moving the salt in a certain way. Peripherally displaced plates may provide a small feeding function, which may be designed to affect the total feeding functionality in a desired way. In one embodiment each plate may be peripherally displaced by a specified amount relative to each of its adjacent plates. Such amount may be 5-30 degrees, for instance about 10 degrees.

According to one embodiment of the invention, the divider element may be a plate arranged in parallel with the feeding screw.

The divider elements may be parallel to the feeding screw and stretching upwards perpendicular to the bottom of the container.

By placing the divider element parallel to the shafts, the risk of the shafts colliding may be reduced. Also, in the case that any of the shafts may swing slightly to touch the divider element, there may be less damage to any of the shafts by having the divider plate arranged parallel to the shafts, since a parallel divider element may smoothly guide the shaft in its channel.

According to one embodiment of the invention, the divider element may extend above the centre of the feeding screw and has a minimum length equal to the distance between two plates.

The divider elements may be measured to reach at least to the centre of the feeding screw. By having a size and shape like that, they may be thin enough to require little space, and at the same time ensure that there may be no collision. Since the widest part of a shape is at the diameter, the highest risk of collision may be at that point along a shaft. By having a divider that reaches at least to the centre, there may a reduced risk of collision.

According to one embodiment of the invention, the container may comprise a bottom surface arranged to contain the salt, wherein the bottom surface may comprise one or more semi circle shaped channels, each arranged to contain one of the agitator and the feeding screw.

In order to contain the salt in a way that may increase the amount of salt be fed through the feeding arrangement, it may be required to reduce the amount of volume below the feeding screw. That is, to decrease any volume that may contain salt that may not exit the container. According to this, it may be suitable to provide the container with a bottom surface that may have the same shape as the feeding screw and the agitator, semi circular channels, and place the feeding screw and the agitator as close to the bottom as possible in a respective channel in order to ensure that as much salt as possible may be scraped off the container bottom and fed through the container towards the exit.

According to one embodiment of the invention, the feeding screw is a first feeding screw, and the feeding arrangement further comprises a second feeding screw arranged parallel with the first feeding screw and the agitator, and wherein the agitator is arranged between the first and the second feeding screw.

It may be an advantage to provide the feeding arrangement with two feeding screws and one agitator placed in between. In that way it may be ensured that any salt that may be shoveled by the agitator may be properly scraped off the container walls and fed on each side of the agitator. However, the feeding arrangement may, depending on the size of the feeding arrangement and amount of content to be shoveled and fed, comprise a plurality of feeding screws and a plurality of agitators, each agitator arranged next to a feeding screw.

Brief description of the drawings

The invention will in the following be described in more detail with reference to the enclosed drawings, wherein:

Fig. 1 is a top view of a feeding arrangement according to an embodiment of the invention,

Fig. 2 is a cross sectional front view of a feeding arrangement according to an embodiment of the invention,

Fig. 3 is a cross sectional front view of a feeding arrangement according to an embodiment of the invention,

Fig. 4 is an perspective view of an agitator according to an embodiment of the invention, and

Fig. 5 is a schematic side view of an agitator according to an embodiment of the invention.

Detailed description of embodiments

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. In the drawings, like numbers refer to like elements.

The feeding arrangement 1 according to an embodiment of the invention is illustrated in fig. 1. The feeding arrangement 1 is arranged in a container 2 having side walls 3. Inside the container 2, two feeding screws 4 are arranged. In between the feeding screws 4, an agitator 10 is arranged.

The agitator 10 consists of a rotatable shaft 12 and a number of plates 14 arranged on the rotatable shaft. The plates are arranged so that when the rotatable shaft 12 is rotated around its own centre axis, the plates 14 may act as shovels, and shovel the content in the container. In fig. 1, the plates are arranged at an angle a relative to the rotatable shaft. The plates 14 in fig. 1 are circular, but may be of any shape suitable. In one embodiment may each plate be elliptical. The elliptical shape provides that a plate 14, when arranged with an angle to the rotatable shaft 12, provides a circular cross-section when seen axially along the rotatable shaft 12. Such circular cross-section provides an even movement of the plates and shoveling. The elliptical shape should be selected with regard to the angle of the plates 14 to the rotatable shaft 12.

In fig. 1 it is shown that the plates 14 are arranged so that the centre points of the plates coincide with the central axis of the rotatable shaft 12. By having elliptical plates 14, arranged by its centre point and with an angle to the rotatable shaft 12, the available space in the container may be used in an effective way. Further in fig. 1, the feeding arrangement is provided with one or more divider plates 5. The divider plates 5 are arranged between the feeding screws 4 and the agitator 10, in order to avoid collision of the feeding screws 4 and the agitator 10. Even though each of the feeding screws 4 and agitator 10 may be made from rigid materials, for instance steel, the rotational movement in combination with the length of the shafts may cause oscillation, and therefore there may be a risk that the shafts may collide.

Fig. 2 depicts a cross sectional front view of the feeding arrangement shown in fig. 1. Fig. 2 further shows that the container 2 has a bottom surface 6. In fig. 2, the bottom surface has semi circled channels 7 on each location of each of the agitator 10 and the feeding screws 4. The channels 7 extend along the entire length of each of the feeding screw 4 and the agitator 10. The semi circled shape may be provided to facilitate emptying of the container due to the reduced number of inside corners and sharp edges, which may arise when having a bottom surface that may be formed with less smooth shapes, where content may be stuck. Since the form of the bottom surface may follow the shape of the feeding screw 4, and the feeding screw 4 may be placed close to the bottom surface, this may facilitate that the feeding screw 4 scrapes the content off the container bottom surface and thereby feeding it towards an exit. Also, by having the bottom surface shaped with a semi circle at the position of the agitator, there is a better chance for the agitator plates 14 to reach a larger portion of the content to be shoveled.

Further it is shown that a divider plate 5 is placed between each shaft. The divider plate 5 may be a rectangular plate, dimensioned so that it covers the axial extension of at least one plate, and may extend to at least a height in level with the centre of the shafts 12. This is to ensure that the divider plate 5 surely may aid to avoid collision between a rotating agitator 10 and a feeding screw 4. There may be a number of divider plates 5 arranged along the length of the container 2. There may also be a smaller number of longer divider plates. The divider plate 5 may be of the similar rigid material as the feeding screws 4 and the agitator 10. Alternatively it may be of another material similarly tough to withstand any colliding forces from the feeding screw 4 and the agitator 10.

In fig. 3, a cross sectional view of an embodiment of the invention is shown. This embodiment has one agitator 10 and one feeding screw 4 separated by a divider plate. It is shown how the plates 14 are arranged angularly relative to the rotatable shaft 12. The structural features of the agitator 10 and the feeding screw 4 in the embodiment described in conjunction with figs. 1 and 2 may apply also to the embodiment of fig. 3. As in fig. 2, the bottom surface 6 is formed to follow the shape of the feeding screw 4 and the agitator 10, i.e. a semi circle. The semi circle may extend as high suitable, possibly up to third of the total height of the feeding screw 4 or the agitator 10, or higher if necessary, such as half of the height of the feeding screw 4 or the agitator 10.

As seen in figs. 2 and 3, the plates 14 in the agitator, arranged with an angle to the rotatable shaft 12, are elliptical to form a circular cross-section.

Fig. 3 shows another embodiment of the invention, where the feeding arrangement 1 comprises one feeding screw 4 and one agitator 10. The feeding arrangement may thus be adapted so suit any need. The feeding arrangement 1 may alternatively comprise a number of agitators 10 and a number of feeding screws 4, for large feeding arrangements 1 in large containers. For instance, a feeding arrangement according to an embodiment of the invention (not shown) may comprise a plurality of feeding screws with an agitator arranged between each screw.

Fig. 4 depicts a perspective view of an agitator 10. The agitator 10 comprises a long rotatable shaft 12 and a number of plates 14 placed at an even distance from each other at an angle relative to the rotatable shaft 12. The distance A between each plate 14 may be calculated in relation to the angle, since it may be an advantage that as large a portion of the shaft as possible is covered by a plate 14 in order to provide effective agitation.

Hence, a large angle may involve a short distance A between plates.

This is further illustrated in fig. 5. The distance A between two plates 14 may be calculated using trigonometry. The distance c may be determined by c = a cos a, wherein a is the radius of the plate 14. In the case where the end points of two adjacent plates 14 coincide along the axial extension of the rotatable shaft 12, as illustrated by the dashed line in fig. 5, the distance between the two plates 14 is 2c = 2a cos a. Hence, in order to make sure plates 14 cover the entire axial extension of the rotatable shaft 12, the distance A between the plates 14 in the agitator may be determined by A < 2a cos a, i.e. A < d cos a wherein d is the diameter of the plate 14. In the case the plate 14 is elliptical, d is the longest diameter of the elliptical plate 14.

The angle may also be calculated depending on a number of factors, i.e. available space in the container as well as the angle that has proven to be most effective. However, the angle may be less than 90 degrees, and possible preferably around 45 degrees.

The plates may be designed for effective agitation of salt or other granular material. The salt may be dense and heavy wherefore the plates may be thick enough to withstand any forces from the compact salt. The plates may have a thickness of about 5-20 millimeters, but may be of any suitable thickness.

In the drawings and specification, there have been disclosed preferred embodiments and examples of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation, the scope of the invention being set forth in the following claims.

Claims

A road salt distribution feed arrangement (1) comprising a container and at least one feed auger (4) disposed to supply salt in the container (2), the feed arrangement (1) further comprising at least one agitator (10) comprising a rotatable shaft (12). ) and a plurality of plates (14), the plates (14) being angularly disposed on the rotatable shaft (12) such that as the rotatable shaft (12) is rotated about its central axis, the plates (14) move about it. rotatable shaft, thereby shoveling the salt into the container (2), characterized in that the agitator (10) is arranged parallel to the supply screw (4) and that the supply arrangement (1) further comprises at least one dividing element (5) disposed between the supply screw (4). and the agitator (10) to avoid collision of the auger (4) and agitator (10).

Supply arrangement (1) according to claim 1, wherein the plates (14) have an elliptical shape.

Supply arrangement (1) according to any of the preceding claims, wherein the plates (14) are arranged such that the center of the plates (14) coincides with the central axis of the rotatable shaft (12).

Supply arrangement (1) according to any of the preceding claims, wherein at least two plates (14) are arranged parallel to each other.

Supply arrangement (1) according to any one of the preceding claims, wherein each plate (14) is disposed at an angle to the rotatable shaft (12) of about 25-65 degrees, preferably about 45 degrees.

Supply arrangement (1) according to any one of the preceding claims, wherein at least two of the plates (14) are arranged at a distance (A) from one another along the rotatable shaft (12) such that the distance (A) is determined by

where d is the diameter of the plates and α is the angle of the plates (14) with respect to the rotatable shaft (12).

Supply arrangement (1) according to any one of the preceding claims, wherein at least one plate (14) is circumferentially displaced relative to another plate.

Supply arrangement (1) according to any one of the preceding claims, wherein the dividing element (5) is a plate arranged parallel to the supply screw (4).

Supply arrangement (1) according to any one of the preceding claims, wherein the dividing element (5) extends above the center of the supply screw (4) and has a minimum length equal to the distance between two plates (14).

Supply arrangement (1) according to any one of the preceding claims, wherein the container (2) comprises a bottom surface (6), wherein the bottom surface (6) comprises one or more semicircular channels (7), each channel (7) being arranged to accommodate one of the agitators (10) and the auger (4).

Supply arrangement (1) according to any one of the preceding claims, wherein the supply screw (4) is a first supply screw (4) and wherein the supply arrangement (1) further comprises a second supply screw (4) arranged parallel to the first supply screw (4) and the agitator (10) and wherein the agitator (10) is disposed between the first and second feed augers (4).