GB2623384A

GB2623384A - A nozzle and a duct coating device

Info

Publication number: GB2623384A
Application number: GB2302588.5A
Authority: GB
Inventors: George Hunt Geoffrey; Guilhelmus Swanenberg Adrianus
Original assignee: Hey Safe Cleaning Solution Ltd
Current assignee: Hey Safe Cleaning Solution Ltd
Priority date: 2023-02-23
Filing date: 2023-02-23
Publication date: 2024-04-17
Also published as: GB202302588D0

Abstract

A device for coating the inside of a duct with a substance comprising; a nozzle 100 with a substance cavity 200 defined by a side wall 500 and an end portion 400 which is perpendicular to axis z, connected to an actuation mechanism 700 (fig 7), for rotation of the nozzle around axis z when in use. Side wall comprises a plurality of slits 600 which are elongate and extend at a non-zero angle to axis z toward end portion. In use a substance can be expelled from the cavity through the slots due to centrifugal force. Optionally the substance may be a cleaner for ducts or pipes in a kitchen.

Description

A NOZZLE AND A DUCT COATING DEVICE

The present disclosure relates to a nozzle. In particular the disclosure is concerned with a nozzle for expelling a substance to coat the inside of a duct. The present disclosure also relates to a duct coating device comprising the nozzle.

Background

Grease may become deposited on ducts, and particularly extraction ducts which are used to extract air from kitchens, during use. This both decreases the extracting action of the duct and greatly increases the risk of fire. If a flame reaches the extraction duct, which is a particular risk in a kitchen, the grease deposit in the extraction duct has a risk of catching fire, leading to destruction of the duct and potentially severe damage to or destruction of the building. Insurance companies therefore lay down strict requirements for the maintenance of extraction ducts. Such ducts have to be cleaned regularly in order to prevent grease deposit and thereby reduce the risk of fire in the duct.

Cleaning extraction ducts is difficult and unpleasant work. Firstly, such ducts are typically difficult to access. They are long and often narrow, and usually also have bends or sharp corners.

Secondly, extraction ducts are not usually suitable for the use of liquid cleaning agents because they are not liquid sealed. For example, extraction ducts are usually formed from sheet metal (e.g., steel) such that they have a rectangular or elliptical/circular cross section, for example. There may be attachment between the various duct parts that does not normally form a liquid sealed connection. Spirally wound ducts of thin sheet metal also exist, which are provided along the edges with folded seams which do not form a liquid sealed connection either. Liquid cleaning agents will thus leak out of the duct to be cleaned. Stains on ceilings or walls behind which the ducts run often occur as a consequence of such leakage. Being unable to make use of cleaning liquids makes it difficult to properly clean extraction ducts and remove the grease deposit formed therein by hand. Such ducts are therefore cleaned less regularly and less thoroughly in practice than would be desirable with a view to fire prevention.

Accordingly, it would be advantageous to provide a means for enabling ducts to require cleaning less frequently, and to enable them to be cleaned more efficiently and effectively.

Summary

According to a first aspect of the present invention there is provided a nozzle configured to expel a substance to coat the inside of a duct, the nozzle comprising: a substance cavity; a coupling portion for connecting to an actuation mechanism such that the actuation mechanism, when operated, causes the nozzle to rotate about a rotation axis; a side wall comprising a plurality of slits; and an end portion comprising an inner end surface perpendicular to the rotation axis, wherein: the substance cavity is defined by the side wall and the end portion; in use, rotation of the nozzle causes the substance within the substance cavity to be expelled through the plurality of slits in a direction away from the rotation axis; and each of the plurality of slits is elongate, and each elongate slit extends in a direction from an edge of the side wall toward the end portion at a non-zero angle relative to the rotation axis.

Optionally, each of the plurality of slits extends toward the end portion at an angle of 45° relative to the rotation axis.

Optionally, the side wall comprises an inward facing surface having a non-zero angle with respect to the rotation axis such that a part of the inward facing surface closest to the end portion is closer to the rotation axis than another part of the inward facing surface closest to the edge of the side wall.

Optionally, the non-zero angle of the inward facing surface with respect to the rotation axis is between 6° and 8°.

Optionally, the side wall surrounds the rotation axis such that the plurality of slits are positioned around the rotation axis.

Optionally, the plurality of slits are spaced apart from one another by the same amount.

Optionally, the side wall defines a height that extends from the edge of the side wall to the end portion of the nozzle and which is parallel to the rotation axis, and each of the plurality of slits is of a length and an inter-slit spacing is such that a portion of each slit of the plurality of slits is arranged to overlap a portion of an adjacent slit of the plurality of slits when viewed along the height of the side wall.

Optionally, each of the plurality of slits defines a width, and the portion of each slit of the plurality of slits arranged to overlap the portion of an adjacent slit of the plurality of slits is equal to one half the width of said slit when viewed along the height of the side wall.

Optionally, the width of each of the plurality of slits is 4 mm.

Optionally, the depth of the substance cavity along the rotation axis is between 30mm and 44 mm.

Optionally, the nozzle is formed of a material comprising polymer.

According to a second aspect of the present invention, there is provided a duct coating device comprising: the nozzle according to the first aspect; and an actuation mechanism coupled to the coupling portion of the nozzle, wherein: the actuation mechanism is configured to rotate the nozzle about the rotation axis.

Optionally, the actuation mechanism is configured to rotate the nozzle according to a set of rotation operations.

Optionally, the actuation mechanism is configured to rotate the nozzle at a circumferential speed of between 10 m/s to 15 m/s at an outer diameter of the nozzle.

Optionally, the actuation mechanism is configured to rotate the nozzle about the rotation axis in a first direction and in a second direction opposite to the first direction.

Optionally, the actuation mechanism comprises an electric motor operable to cause the nozzle to rotate in the first direction and in the second direction.

Brief Description of the Drawings

Examples of the present disclosure will now be described with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of a nozzle, according to examples; Figure 2 is a schematic plan view of the nozzle, according to examples; Figure 3 is a schematic expanded plan view of the nozzle, according to examples; Figure 4 is a schematic front cross-sectional view of the nozzle, according to examples; Figure 5 is a schematic front view of the nozzle, according to examples; Figure 6 is a schematic side cross-sectional view of the nozzle, according to examples; Figure 7 is a schematic plan view of a duct coating device, according to examples; Figure 8 is a schematic perspective view of the duct coating device, according to examples; Figure 9 is a schematic perspective view of the duct coating device, according to

examples; and

Figure 10 is a schematic perspective view of the duct coating device, according to examples, inside of a duct.

Detailed Description

The present disclosure relates to a nozzle configured to expel a substance to coat the inside of a duct. The nozzle described herein provides various advantages in relation to applying a substance to the inner surface of a duct to reduce grease build-up within the duct.

Examples of the nozzle comprise a substance cavity. The nozzle further comprises a coupling portion for connecting to an actuation mechanism such that the actuation mechanism, when operated, causes the nozzle to rotate about a rotation axis. The nozzle also comprises a side wall comprising a plurality of slits, and an end portion comprising an inner surface perpendicular to the rotation axis. The substance cavity is defined by the side wall and the end portion. In use, rotation of the nozzle causes the substance within the substance cavity to be expelled through the plurality of slits in a direction away from the rotation axis. Each of the plurality of slits is elongate, and each elongate slit extends in a direction from an edge of the side wall toward the end portion at a non-zero angle relative to the rotation axis. It will be appreciated that a slit is a long, narrow cut or opening. In examples, each elongate slit forms a through hole.

Figure 1 is a schematic perspective view of a nozzle 100, according to examples. The nozzle 100 comprises a substance cavity 200. The nozzle 100 further comprises a side wall 500 comprising a plurality of slits 600, and an end portion 400 comprising an inner end surface 410 perpendicular to the rotation axis Z. The substance cavity 200 is defined by the side wall 500 and the end portion 400.

Each of the plurality of slits 600 is elongate, and each elongate slit 600 extends in a direction from an edge 510 of the side wall 500 toward the end portion 400 at a non-zero angle relative to the rotation axis Z. The edge 510 of the side wall 500 is towards an opposite end of the nozzle than the end portion 400. For example, the edge 510 of the side wall 500 is where the substance cavity 200 ends. In these examples, each of the plurality of slits 600 extends toward, but does not contact, the edge 510 of the side wall 500. In these examples, each of the plurality of slits 600 extends toward, but does not contact, the end portion 400.

In these examples, the side wall 500 surrounds the rotation axis Z such that the plurality of slits 600 are positioned around the rotation axis Z. For example, the nozzle 100 forms a substantially cylindrical shape by virtue of the side wall 500 surrounding the rotation axis Z. In other words, the nozzle 100 has a body having a substantially cylindrical form. For example, the nozzle 100 has a substantially circular cross-section when taken perpendicular to the rotation axis Z. The previously mentioned rotation axis Z corresponds to the central longitudinal axis of the cylindrical shape. In other words, the rotation axis Z is positioned at the centre of the nozzle 100. In other words, the side wall 500 meets the end portion 400 such that the end portion 400 effectively closes off the cylindrical shape to provide the substance cavity 200. In these examples, the nozzle 100 is open at an end opposite to the end portion 400. For example, the edge 510 of the side wall 500 is at the open end of the cylindrical shape. For example, the nozzle 100 has a form similar to a cylinder with one end closed off. More specifically, an inward facing surface 502 of the side wall 500 and the inner end surface 410 form the boundaries of the substance cavity 200.

As shown in Figures 1, the side wall 500 surrounds the rotation axis Z such that the plurality of slits 600 are positioned around the rotation axis Z. Therefore, the nozzle 100 forms a cylinder in which the outer surface 512 of the side wall 500 forms the face or curved surface of the cylinder. The plurality of slits 600 are positioned around the circumference of the cylinder. The plurality of slits 600 may be spaced apart from one another by the same amount. The plurality of slits 600 may be spaced apart from one another by different amounts.

The non-zero angle of the elongate slits 600 means that the longitudinal axis of the elongate slits 600 (aligned with the largest spatial dimension, namely the length, of the elongate slits 600) is not parallel to the rotation axis Z. In other words, the non-zero angle of the elongate slits 600 means that each of the plurality of slits 600 does not extend toward the side wall edge 510 and the end portion 400 in a direction parallel to the rotation axis Z. For example, viewed from a direction perpendicular to the rotation axis Z, the elongate slits 600 form a non-zero angle relative to the rotation axis Z. In other words, the slits 600 are oblique relative to the rotation axis Z when the nozzle 100 is viewed from a direction perpendicular to the rotation axis Z. For example, moving in a direction along the rotation axis Z, each slit 600 spans a portion of the circumference of the cylinder greater than the width of said slit 600.

Figure 2 is a schematic plan view of the nozzle 100, according to examples. For example, in the plan view of Figure 2, the elongate slits 600 form a non-zero angle relative to the rotation axis Z such that they appear diagonal in the orientation shown. Referring to the examples of Figure 2, each slit has a first end 630 and a second end 640. One of the first and second ends 630, 640 of each given slit 600 is positioned closer to the edge 510 than the other of the first and second ends 630, 640 of that given slit. The longitudinal axis of the slit extends between the first and second ends 630, 640.

In the examples of Figure 2, there is indicated a specific slit 600a having the first end 630a and the second end 640a. To further describe the angle of the specific slit 600a relative to the rotational axis Z, there is indicated a perpendicular axis 302, which is perpendicular to the rotational axis Z. The specific elongate slit 600a is angled such that the first end 630a is at a different position along the perpendicular axis 302 than the second end 640a. For example, all of the plurality of slits 600 have a non-zero angle relative to the rotation axis Z, which may be described in this way.

In some examples, each of the plurality of slits 600 extends toward the end portion 400 at an angle of 45° relative to the rotation axis Z. However, in other examples, other non-zero angles may be utilised. The angle of 45° relative to the rotation axis Z may be particularly advantageous, as described later.

In the examples of Figure 2, each of the plurality of slits 600 extends toward the end portion 400 at an angle of 45° relative to the rotation axis Z. In other words, each of the plurality of slits 600 extends at angle a equal to 45° relative to the rotation axis Z. However, this is only an example, and each of the plurality of slits 600 may extend toward the end portion 400 at an angle other than 45° relative to the rotation axis Z. In these examples, the nozzle 100 comprises a coupling portion 300 (see Figure 1) for connecting to an actuation mechanism 700. The coupling portion 300 comprises a connection structure 310 (described in further detail below) configured to connect to an actuating portion of the actuation mechanism 700. In the examples shown in the Figures, the coupling portion 300 has a circular cross section in a plane perpendicular to the rotation axis Z. For example, the nozzle 100 and the coupling portion 300 are concentric.

In the examples of Figure 1, the coupling portion 300 is centred within the substance cavity 200.

For example, the coupling portion 300 in located in the centre of the nozzle 100. The substance cavity 200, defined by the side wall 500 and the end portion 400 of the nozzle 100, may form an annular ring around the coupling portion 300.

The actuation mechanism 700, when operated, causes the nozzle 100 to rotate about a rotation axis Z. The actuation mechanism 700 causes such rotation by virtue of its connection to the coupling portion 300. In use, the substance to be expelled is deposited in the substance cavity 200, for example. For example, the substance is deposited onto the inner end surface 410 of the end portion 400. In use, rotation of the nozzle 100 causes the substance within the substance cavity 200 to be expelled through the plurality of slits 600 in a direction away from the rotation axis Z. For example, a substance for coating the inside surface of a duct may be introduced (e.g., injected or otherwise deposited) into the substance cavity 200 of the nozzle 100. Rotation of the nozzle 100 causes the substance that is located within the substance cavity 200 to move in a direction away from the centre of the nozzle 100 and toward the side wall 500. The substance is urged to move in this direction due to centrifugal force applied on the substance due to the rotation of the nozzle 100. The substance is expelled from the nozzle 100 through the plurality of slits 600. The substance is expelled in a direction away from the rotation axis Z. As previously described, the elongate slits 600 extend in a direction from the edge 510 of the side wall 500 toward the end portion 400 at a non-zero angle a relative to the rotation axis Z. This helps the nozzle 100 to maintain its shape during rotation. For example, the elongate slits 600 being at such an angle may inhibit the nozzle 100 from experiencing distortion in its physical shape in a twisting manner due to the rotational force applied by the actuation mechanism 700. As an example, if there were provided elongate slits which extended from the edge 510 of the side wall 500 toward the end portion 400 in a direction parallel to the rotation axis, the nozzle 100 may be weakened such that the rotational force causes the nozzle 100 to twist. Even if the nozzle 100 later returns to its original shape, the contortion during the rotation may have an adverse effect on the manner in which the substance is expelled. For example, the substance may not be dispersed at the desired quantity, rate, pattem, and the like. Accordingly, one advantage of the described angle of the elongate slits is to provide rigidity to the nozzle with respect to rotation about the rotation axis Z. Other advantages of the described configuration of the elongate slits are described below.

The side wall 500 and the plurality of slits 600 act as a guide to control the exit of the substance from the substance cavity 200. For example, the side wall 500 and the plurality of slits 600 act as a guide for the dispersion of the substance from the nozzle 100. Rotation of the nozzle 100 causes the substance within the substance cavity 200 to move toward the side wall 500 and the plurality of slits 600 (due to the described centrifugal force). The substance is expelled through the plurality of slits 600 in a controlled manner to form a coating on the inner surface of a duct inside which the nozzle 100 is positioned (for example, with advantageous surface properties discussed further below).

Figure 4 shows a schematic front cross-sectional view of the nozzle 100, according to examples. The cross section is taken in a plane perpendicular to the rotation axis Z. In Figure 4, the rotation axis Z points into/out of the page and is indicated by a cross inside a circle representing the tail of an arrow. For example, Figure 4 shows a thickness T of the side wall 500. The thickness T

B

of the side wall 500 as referred to herein is radial relative to the rotation axis Z. For example, the thickness of the side wall 500 may be measured along a radial direction relative to the rotation axis Z. It will be appreciated that a radial direction relative to the rotation axis Z is any direction perpendicular to the rotation axis Z and originating from/terminating at the rotation axis Z. In some examples, each of the plurality of slits 600 comprise a first slit wall 610 and a second slit wall 620, wherein each of the first and second slit walls 610, 620 may be defined to follow the shortest path between the substance cavity 200 and the outer surface 512 of the side wall 500. For example, the outer surface 512 of the side wall 500 is the surface facing away from the rotation axis Z. In the examples of Figure 4, the slit walls 610, 620 are parallel to radial lines relative to the rotation axis Z. In the examples of Figure 4, there is shown a radial line 202 extending radially outwards from the rotational axis Z. As previously described, the rotation axis Z is at the centre of the nozzle 100. Therefore, "radial lines" in these examples also extend radially with respect to the central longitudinal axis of the nozzle 100.

In these examples, the first slit wall 610 is substantially parallel to the radial line 202. In other words, if an imaginary line was extended outwardly from the centre of the nozzle and remained parallel to the first slit wall 610, that imaginary line would intersect with a tangent line of the outer surface 512 at the position of the first slit wall 610 at an angle of 90°. For example, there may be considered a respective radial line for each of the slit walls 610, 620 of each slit 600, relative to which radial line, the angle of the slit wall in question is zero. In other examples, the slit walls 610, 620 may not follow the shortest path between the substance cavity 200 and the outer surface 512 of the side wall 500. For example, each slit wall 610, 620 may be at a non-zero angle relative to a respective radial line which intersects said slit wall.

The slits 600 may be created in various ways, as discussed further below. For example, in examples where a cutting technique is used to create the slits 600 in the side wall 500, the slits may be cut into the side wall 500.

For example, the plurality of slits 600 are equal to one another in length. This allows for equal dispersion of the substance within the substance cavity 200. In other words, this allows for equal division of the product exiting the nozzle 100 among the slits 600. The length of the plurality of slits 600 may depend on a size of the side wall 500 along the rotation axis Z (in other words, the height H). For example, the size of the side wall 500 along the rotation axis Z defines a depth D (see Figure 6) of the substance cavity 200 for a given thickness of the end portion 400. Given that the slits are formed in the side wall 500, the length of the slits 600 is limited by the physical size of the side wall 500.

As previously described, each elongate slit 600 extends in a direction from an edge 510 of the side wall 500 toward the end portion 400 at a non-zero angle relative to the rotation axis Z, for example. In some examples, each of the plurality of slits 600 may be of a length and the inter-slit spacing may be such that each slit of the plurality of slits 600 is arranged to overlap an adjacent slit of the plurality of slits 600 when viewed from a direction parallel to the rotation axis Z. In other words, the plurality of slits 600 may be spaced such that, and each of the plurality of slits 600 may be of a length such that, each slit of the plurality of slits 600 is arranged to overlap an adjacent slit of the plurality of slits 600 when viewed from a direction parallel to the rotation axis Z. In other words, a slit of the plurality of slits 600 overlaps the adjacent slit on a first side, and is overlapped by the adjacent slit on a second side. That is, a portion of each of the plurality of slits 600 is overlapped by the adjacent slits on either side. For example, the slits overlapping as described means that if a line is drawn parallel to the rotation axis from the end portion 400 to the edge 510, there is a region of each given slit where such a line would intersect that given slit and an adjacent slit.

As an example, in Figures 2 and 3, the described overlap of slits is shown. There is shown a specific slit 600a (which will be referred to as the first slit 600a in the context of the overlap) and a second specific slit 600c. As an example, in Figure 2 there is shown a line 204 which is parallel to the rotation axis. The line 204 may correspond to the trajectory of some of the substance as it moves in the direction of the edge 510. The line 204 intersects the first slit 600a at a region closer to the second end 640a than the first end 630a. The line 204 also intersects the second slit 600c at a region closer to the first end 630c than the second end 640c. This illustrates the overlap being referred to. As the substance moves along the line 204 from the end portion 400 towards the edge 510, there is always a portion of a slit that the substance encounters. In other words, all of the substance moving towards the edge 510 encounters a slit, and an amount of the substance does not reach the edge 510 because all the substance encounters slits so as to be expelled through the slits by virtue of the described overlap. In this way the substance moving towards the edge 510 has the opportunity to exit through the slits and does not miss the slits 600.

For example, the side wall 500 defines the height H that extends from the edge 510 of the side wall 500 to the end portion 400 of the nozzle 100. The height H of the side wall 500 is parallel to the rotation axis Z. Each of the plurality of slits 600 is of a length such that a portion of each slit of the plurality of slits 600 is arranged to overlap a portion of an adjacent slit when viewed along the height H of the side wall 500. In the example of Figure 3, when the nozzle 100 is viewed circumferentially, the first end 630c of second slit 600c starts at a position corresponding to line 206. The second end 640a of the first slit 600a ends at a position corresponding to line 208. The length difference between line 206 and line 208 corresponds to one-half the diameter of a circle C fitting at the end of first slit 600a or second slit 600c. In other words, in these examples, the overlap between first slit 600a and second slit 600c corresponds to one-half the diameter of the circle C fitting at the end of first slit 600a or second slit 600c. In other words, the overlap between first slit 600a and second slit 600c corresponds to one-half of the width of the slits 600, in the examples of Figure 3.

According to an example, each of the plurality of slits 600 may define a width W of 4 mm. The width W of each of the plurality of slits 600 may be less than or more than 4 mm. Each of the plurality of slits 600 may define an identical width W. For example, each slit may have the same width. In alternative examples, the widths of the plurality of slits 600 may vary. As an example, in Figure 3 the described overlap of the slits 600 is one half the width W of the slit, as described above. In other words, the overlap of the slits is one half of the width W of the slits when viewed along the height H of the side wall 500. In other examples, the overlap of the slits may be more, or less, than one half of the width of the slits.

An overlap equal to one-half of the width of the slits 600 may be enough such that the substance does not reach the edge 510 (although other factors which affect how far towards the edge 510 the substance travels are also discussed herein). For example, an overlap equal to one-half of the width of the slits 600 may be enough to achieve the result that all of the substance within the nozzle moving towards the edge 510 encounters a slit 600 and has the opportunity to be expelled in the desired manner.

In use, the substance within the substance cavity 200 moves toward the plurality of slits 600 and is continuously supplemented with more of the substance fed into the nozzle 100. Although in the above description reference is made to some of the substance moving along the line 204, movement of the substance within the nozzle 100 during rotation, toward the plurality of slits 600, may be described as one flow. In other words, the substance may be said to form a substance disk (by rotation). The disk of substance, which is continuously supplemented with substance being fed into the nozzle 100, is forced toward all of the plurality of slits 600. For example, the edge of the substance at any point along the inward facing wall 502 follows a flow path which is a straight line from end surface 410 to edge 510, for example as indicated by the line 204.

Advantageously, the described overlap of the slits means that as the substance moves towards the edge 510, there is always a portion of a slit which the substance encounters such that the substance can exit in a radial direction from the nozzle 100. Therefore, it is less likely that some of the substance may reach the edge 510 and be expelled from the nozzle in an undesired manner. Accordingly, by using the described arrangement of slits, the amount of substance which simply exits through the open end of the nozzle 100 may be reduced/avoided.

As previously described, the slits 600 extend from the edge 510 towards the end portion 400 at a non-zero angle relative to the rotation axis Z. As described above, in some examples that angle is 45 °. For example, it will be appreciated that the amount of overlap of the slits 600 may be varied based on the angle a of the slits 600, the length of the slits 600, distance between adjacent slits and the like. Such parameters may be chosen according to the desired amount of overlap, for example, in combination with other considerations such as a spray width S. For example, the spray width S is the width of the coverage of the substance on an inside wall 10 of the duct being coated for a particular position of the nozzle within the duct. For example, the spray width S relates to the amount of the inside wall 10 of the duct along the rotation axis Z which is covered, when the nozzle 100 is held at a particular position along the duct. Figure is a schematic perspective view of an example nozzle inside a duct. Figure 10 illustrates what is meant by the spray width S. The spray width S depends, for example, on the spacing between slits 600 and the angle relative to the rotation axis Z at which the slits extend between the edge 510 and the end portion 400.

As described above, in some examples the angle is 45°. An angle of 45° may be best suited for achieving the optimum spray width an other words, the largest spray width S). The spacing between adjacent slits and therefore the number of slits depends on the height H and the total diameter of the nozzle. For example, to maintain the above-described overlap of one-half of the slit width and to maintain the 45° angle, if the diameter is held constant and the height H is increased, then fewer slits 600 are needed. Conversely, to maintain the above-described overlap of one-half of the slit width and to maintain the 45° angle, if the height H is held constant and the diameter is increased, a greater number of slits 600 will be needed. It may be desired to achieve a nozzle having the above-described overlap of one-half of the slit width and to maintain the 45° angle of the slits 600.

It will be appreciated that the centrifugal force on the substance within the substance cavity 200 when the nozzle 100 is rotating causes the substance to move radially outwards towards the side wall 500. As previously described, the inward facing surface 502 of the side wall 500 and the inner end surface 410 of the end portion 400 form the boundaries of the substance cavity 200. In some examples where the inward facing surface 502 of the side wall 500 is parallel to the rotation axis Z, the substance may not readily move along the inward facing surface 502 towards the edge 510 of the side wall 500.

In some examples, the inward facing surface 502 of the side wall 500 has a non-zero angle with respect to the rotation axis Z such that a part of the inward facing surface 502 closest to the end portion 400 is closer to the rotation axis Z than another part of the inward facing surface 502 closest to the edge 510 of the side wall 500. For example, the inward facing surface 502 is angled relative to the rotation axis Z such that the inward facing surface moves away from the rotation axis Z towards the edge 510.

Figure 5 is a schematic front view of the nozzle 100. It should be noted that in Figure 5, a simplistic depiction of the slits 600 is shown simply as solid lines, for simplicity of depiction. In the examples of Figure 5, there is a first part 504 of the inward facing surface 502 closest to the end portion 400. Figure 6 is a schematic side cross-sectional view of the nozzle 100, according to examples. The first part 504 of the inward facing surface 502 can be seen in the cross section of Figure 6, for example. The first part 504 of the inward facing surface 502 joins up with the inner end surface 410 of the end portion 400. For example, as the substance moves towards the side wall 500 due to the centrifugal force (as indicated by arrow 602), the substance may reach the region where the inner end surface 410 meets the first part 504 of the inward facing surface 502. In these examples, the first part 504 forms an obtuse angle with respect to the inner end surface 410 (note, in these examples, the inner end surface 410 is perpendicular to the rotation axis Z). In other words, the first part 504 forms an angle greaterthan 90° with respect to the inner end surface 410.

Also, in the examples of Figures Sand 6, there is a second part 506 of the inward facing surface 502 closest to the edge 510 of the side wall 500. The second part 506 meets the edge 510 of the side wall 500. As seen in particular from Figure 6, the described non-zero angle of the inward facing surface 502 with respect to the rotation axis Z means that the second part 506 is further away from the rotation axis Z (and therefore the centre of the nozzle 100) as compared to the first part 504. In other words, the distance between the centre of the nozzle 100 and the region where the inward facing surface 502 meets the edge 510 is greater than the distance between the centre of the nozzle 100 and the region where the inward facing surface 502 meets the inner end surface 410, for example.

In the examples of Figure 5 and 6, the non-zero angle of the inward facing surface 502 is achieved by having a varied thickness of the side wall 500. For example, keeping the outer diameter of the side wall 500 constant along the rotation axis Z, the thickness of the side wall 500 is tapered such that it is thinner closer to the edge 510. For example, the side wall 500 is thicker towards the inner end surface 410 compared to its thickness further towards the edge 510. In such examples, the depth of the slits 600 varies along the rotation axis Z. For example, slit walls towards the first ends 630 have a smaller height as compared to the slit walls towards the second ends 640.

In other examples, the non-zero angle of the inward facing surface 502 may be achieved by other means, for example by creating an obtuse angle between the entire side wall 502 and the inner end surface 410 such that the outer diameter of the nozzle increases towards the edge 510. It will be appreciated that the slits 600 are where the substance exits outwards and away from the rotation axis Z. The manner in which this described non-zero angle is provided may depend on whether it is desired to have varying distance along the rotation axis Z between the slits 600 and the rotation axis Z, or not. Such a varying distance between the slits 600 and the rotation axis Z may affect the characteristics of the coating of the substance on the surface(s) being coated, for example.

Advantageously, the non-zero angle of the inward facing surface 502 of the side wall 500 aids in the substance moving along the inward facing surface 502 towards the edge 510, and therefore encountering the slits 600 so that it can be expelled. It will be appreciated that when the nozzle 100 rotates about the rotation axis Z, the centrifugal force acts radially, that is to say perpendicular to the rotation axis Z. The component of the centrifugal force parallel to the rotation axis Z is zero. However, there is a non-zero component of the centrifugal force along the inward facing surface 502 of the examples of Figures 5 and 6, because the inward facing surface 502 is not parallel to the rotation axis Z. Accordingly, in these examples, the centrifugal force can advantageously be utilised to urge the substance along the inward facing surface 502 and towards the edge 510 such that the substance encounters the slits.

In some examples, the described non-zero angle between the rotation axis Z and the inward facing surface 502 is between 6° and 8°. For example, such angles may advantageously aid in the substance moving towards the edge 510, without moving in said direction so quickly that the substance exits the substance cavity 200 past the edge 510, (for example, for the given manners of rotation actuation described further below, and other parameters). When the inward facing surface 502 of the side wall 500 forms the described non-zero angle relative to the rotation axis Z, it can be said to form an applied angle.

The influence of the arrangement of the slits 600 on the spray width S is discussed above. Given an arrangement of the slits 600, maximizing the spray width S may mean achieving the maximum spray width S allowed for by the slit arrangement in question (e.g., 45° angle slits with overlap equal to half a slit width). For example, dispersion of the substance is determined by a combination of parameters including viscosity of the substance, the angle of the inward facing surface 502 of the side wall 500 relative to the rotation axis Z (the applied angle), speed of rotation of the nozzle 100, and the rate at which the substance is introduced into the substance cavity 200 of the nozzle 100 (hereafter referred to as the feed of the substance). The combination of parameters may be chosen to optimise spray pattern and spray width S. For example, in order to obtain a consistent spray pattern, the angle of the inward facing surface 502 of the side wall 500 (the applied angle) may be greater for a substance having a higher viscosity than for a substance having a lower viscosity (for a given set of the other relevant parameters). For example, by providing a greater applied angle, there may be greater alignment with the centrifugal force such that a larger component of the centrifugal force urges the substance to move towards the edge 510. A greater applied angle may be more suitable for a more viscous substance which requires more force to urge it towards the edge 510. On the other hand, a smaller applied angle may be suitable for a less viscous substance such that an excess of force is not applied to cause the less viscous substance to reach the edge 510.

Rotational speed of the nozzle 100 also affects spray pattern. For example, if the rotational speed of the nozzle 100 is too fast, the spray width S may be reduced because the substance has been expelled from the nozzle 100 through the slits 600 before it reaches the end of each slit 600. In other words, the substance may be expelled from the slits 600 through a portion of each slit 600, and not along the entire length of each slit 600. In order to obtain a consistent and desired spray pattern and to maximize the spray width, the applied angle and the rotational speed is chosen according to the viscosity of the substance such that the whole length of the slits 600 is used to expel the substance. For example, the feed of the substance should be high enough so as not to adversely affect the constant flow of the substance given the applied angle, viscosity and rotational speed, as well as the rate at which the substance is expelled from the slits. As an example, the greater the rotational speed, the greater the feed of the substance should be.

The depth D of the substance cavity 200 along the rotation axis Z is between 30mm and 40 mm.

That is, a distance from the edge 510 of the side wall 500 to the inner surface 410 of the end portion 400 is between 30mm and 40 mm. The coupling portion 300 may have a depth of between 30mm and 40 mm. That is, the coupling portion 300 may have the same depth D as the substance cavity 200 along the rotation axis Z. In an alternative example, the coupling portion 300 may have a depth shorter than, or longer than, the substance cavity 200.

The nozzle 100 may be formed of a material comprising a polymer. That is, the nozzle 100 may be formed of plastic. The nozzle 100 may be formed by a method such as moulding, extrusion, or 3-D printing. The components of the nozzle 100 may be formed of the same material. That is, the coupling portion 300, the end portion 400, and the side wall 500 may be formed of the same material. Alternatively, different parts of the nozzle may be formed of different materials. For example, the connection structure 310 may comprise an orifice with a metal insert and the like (see description of the connection structure 310 further below). The material may be a lightweight material. The material may be food safe.

In other examples, the nozzle 100 may be formed of a metallic material. For example, known metal working techniques may be used to form the described features.

Various techniques may be used to form the described features of the nozzle 100 such as punch cutting, laser cutting, machining, drilling, moulding, bending and the like.

The components of the nozzle 100 may be integrally formed. That is, the coupling portion 300, the end portion 400, and the side wall 500 may be integrally formed such that they define a monolithic structure rather than a structure assembled from separate parts. In some examples, the nozzle 100 may be assembled from separate parts.

The present disclosure further relates to a duct coating device 1000 comprising the nozzle 100 according to any one of the described examples and an actuation mechanism 700 coupled to the coupling portion 300 of the nozzle 100, wherein, the actuation mechanism 700 is configured to rotate the nozzle 100 about the rotation axis Z. Figure 7 is a schematic plan view of a duct coating device 1000, according to examples. The actuation mechanism 700 is configured to rotate the nozzle 100 about the rotation axis Z. In the example shown in Figure 7, the actuation mechanism 700 is configured to be coupled to the coupling portion 300 such that the actuation mechanism 700 and the nozzle 100 are aligned along the rotation axis Z. In other words, the actuation mechanism 700 and the nozzle 100 share a central axis, which is the rotation axis Z. As previously described, the coupling portion 300 comprises a connection structure 310, for example. In the examples of Figure 1, 4, 5, 8, and 9 the connection structure 310 is an orifice configured to receive an actuation portion 710 of the actuation mechanism 700. For example, the actuation portion 710 may be a drive shaft 710 which rotates when the actuation mechanism 700 operates. For example, the drive shaft 710 engages with the connection structure 310 in a manner such that rotation of the drive shaft 710 causes rotation of the nozzle 100.

In the examples of Figure 1, 4, 5, 8, and 9 the connection structure 310 is an orifice with a hexagonal cross section. In these examples, the hexagonal orifice receives a shaft connection insert 320, which is inserted into the connection structure 310. In cross-section, the outer surface of the shaft connection insert 320 forms a hexagonal shape to fit into the hexagonal orifice (connection structure 310). It will be appreciated that the shaft connection insert 320 does not rotate within the hexagonal orifice of the connection structure 310. In these examples, the shaft connection insert 320 comprises a circular orifice. The circular orifice is configured to receive the drive shaft 710. The drive shaft 710 may be releasably coupled to the shaft connection insert 320 with screws, pins, or the like, such that when coupled, the drive shaft 710 fits into and does not rotate within (independently of) the shaft connection insert 320, and therefore the connection structure 310. The shaft connection insert 320 may be metal. It should be noted that hexagonal and circular are merely specific examples of the connection structure 310 orifice and shaft connection insert 320, respectively. Other cross sections may be used in this kind of mechanism.

In other examples, the connection structure 310 may be an orifice with a circular cross section, and the drive shaft 710 may be releasably coupled to the connection structure 310 directly (without use of an insert) with screws, pins, or the like, such that when coupled the drive shaft 710 fits into and does not rotate within (independently of) the connection structure 310.

In other examples, there may not be a connection structure 310 which is an orifice for receiving a shaft. Instead, the coupling portion 300 may be configured to be gripped by its outer surface for example, and rotated by a gripping portion of the actuation mechanism 700, and the like.

Those skilled in the art will appreciate the various different ways in which a component of an apparatus may be caused to rotate.

Figures 8 and 9 are schematic perspective views of a duct coating device 1000, according to examples. In these examples, the drive shaft 710 is a shaft with a circular cross section. The connection structure 310 has an orifice with a hexagonal cross section and a shaft connection portion 320 configured to receive the drive shaft 710 such that the drive shaft fits into and does not rotate within (independently of) the connection structure 310. In the example of Figure 8, the drive shaft 710 of the actuation mechanism 700 and the coupling portion 300 are uncoupled.

Figure 9 shows the device 1000 of Figure 8 wherein the actuation portion 710 and the coupling portion 300 are coupled. In these examples, the drive shaft 710 and the nozzle 100 are aligned along the rotation axis Z. In other words, the drive shaft 710 and the nozzle 100 share a central axis, which is the rotation axis Z. It should be noted that in Figures 8 and 9, a simplistic depiction of the slits 600 is shown simply as solid lines.

The actuation mechanism 700 may be configured to rotate the nozzle 100 about the rotation axis Z in a first direction and in a second direction opposite to the first direction. That is, the actuation mechanism 700 may rotate the nozzle 100, during use, in a clockwise direction and/or a counterclockwise direction about the rotation axis Z. Advantageously, providing rotation in opposing directions may provide better coverage of the substance on the inside of the duct in question. For example, there may be structures inside the duct which are not well coated with rotation only in the first direction. In such examples, the nozzle 100 may be rotated in the second direction (additionally, or alternatively) when in the vicinity of such structures.

The actuation mechanism 700 may be configured to rotate the nozzle 100 according to a set of rotation operations. That is, the actuation mechanism 700 may, in use, cause the nozzle 100 to rotate in a first direction and/or a second direction according to a set of rotation operations, i.e., a particular rotation pattern. In other words, the actuation mechanism 700 may be configured to rotate the nozzle 100 about the rotation axis Z in a clockwise direction and in a counterclockwise direction according to a preset pattern or set of rotation operations.

For example, when the device is used in a square duct, spinning of the nozzle in a first and a second direction allows the substance expelled from the plurality of slits 600 to coat inside the corners of the square duct. By contrast, a nozzle that spins in one direction only may not coat the corners effectively and may result in gaps in the coating in some examples. That is, the coating may not reach into the corners. By rotating the nozzle in a second direction opposite to the first direction, the pattern of the sprayed substance may coat areas not covered by the spray in the first direction.

According to some examples, the actuation mechanism 700 may be configured to rotate the nozzle 100 at a circumferential speed of between 10 m/s to 15 m/s at an outer diameter of the nozzle 100. That is, the circumferential speed may be between 10 m/s to 15 m/s as measured at an outer surface of the side wall 500 of the nozzle. However, this is merely an example, and the speed is variable to control the amount of substance, or formulation, that is expelled through the plurality of slits 600 In some examples, the circumferential speed (at the outer diameter of the nozzle 100) is 13 m/s ± 10%.

According to an example, the actuation mechanism 700 comprises an electric motor operable to cause the nozzle 100 to rotate in the first direction and in the second direction. Use of an electric motor with a nozzle according to the examples above may provide a duct coating device that creates a coating having a surface with consistent and controlled dimples, as described further below. The invention is not limited to an electric motor, for example the actuation mechanism 700 may comprise an air-driven mechanism.

The following is a description of examples of use of the duct coating device 1000.

According to an example, the actuation mechanism 700 is configured to rotate the nozzle 100 such that rotation of the nozzle 100 causes a substance within the substance cavity 200 to be expelled through the plurality of slits 600 in a direction away from the rotation axis Z. In use, the nozzle 100 maintains its original shape due its structural rigidity.

The actuation mechanism 700 may be coupled to the coupling portion 300 such that the drive shaft 710 of the actuation mechanism 700 is received (e.g., inserted) into the connection structure 310. The connection structure 310 may be any shape suitable to receive the shaft of the actuation mechanism 700 to allow the actuation mechanism 700 to rotate the nozzle 100.

The actuation mechanism 700 may be fixed in place using suitable fixing means, for example screws or pins.

In use, a substance for coating the inner surface of an extraction duct is introduced into the substance cavity 200 of the nozzle 100.

Rotation of the nozzle 100 causes the substance to be expelled through the plurality of slits 600 in a direction away from the rotation axis 1 That is, as the nozzle 100 rotates, the substance is expelled outward from approximately a centre of the substance cavity 200 toward the side wall 500 of the nozzle 100. The structure of the side wall 500 controls dispersion of the substance, and the substance may exit the substance cavity 200 through the plurality of slits 600. That is, rotation of the nozzle 100 urges the substance toward the side wall 500 according to a centrifugal force. During operation, the nozzle 100 is configured to spin to produce a constant spray of coating substance, so that the inside of the duct is coated evenly and there are no areas which are not coated.

In use, the duct coating device 1000 comprising the actuation mechanism 700 and the nozzle 100 is guided through a duct (e.g., an extraction duct) while the actuation mechanism 700 rotates the nozzle 100 and a substance is introduced into the substance cavity 200 of the nozzle 100. Rotation of the nozzle 100 causes the substance to be expelled from the nozzle 100 through the plurality of slits 600 in a direction away from the rotation axis Z. This forms a coating on the inner surface of the duct. The coating on the duct may have a thickness of 1.5 mm. The coating may have an uneven surface which is a function of the composition of the substance and the pattern resulting from expulsion of the substance through the plurality of slits 600. The surface of the coating may have a dimpled appearance. For example, the dimples formed by the substance striking the duct surface may be round. In other examples, the dimples may have a polygonal shape, such as hexagonal.

The duct coating device 1000 may be guided by pulling or by pushing the device along the duct. Any suitable method may be used to guide the device along the duct, for example a pushrod, a chain, a rope and the like. A method and/or structure may be used to position the device 1000 within the duct, for example, to maintain the device 1000 in the centre of the duct. Ideally, the coating is applied before the duct in question has been used.

Kitchen extraction ducts typically require cleaning every three months to remove grease deposits. Ducts treated with a coating, for example, as provided for by the present disclosure do not require cleaning as often because coating of the duct forms a seal on the surface of the duct and provides a surface that reduces the amount of grease that deposits on the inner surface of the duct during use. Reduction of grease deposits is achieved in three ways.

Firstly, coating the duct creates a seal on the metal inner surface of the duct. Duds are typically made of metal, which is "earthed", and grease is more likely to deposit on an "earthed" surface. A duct coated as provided for by the present disclosure no longer presents an earthed surface for the grease to deposit on, and hence grease remains suspended in the gas/air and goes through the duct without depositing.

Secondly, coating the duct reduces the heat transfer rate between the inside and outside of the duct, resulting in a higher temperature at the outlet. For example, in a kitchen exhaust duct, grease carried by the air flowing through the duct may condense on the surface of the duct as a result of the temperature difference between the duct surface and the hot air. Grease that does not condense will exit the duct with the airflow. Typically, 85% of grease carried by the air leaves the duct system at the outlet. When the inner surface of the duct is coated as provided for by the present disclosure, heat transfer through the duct wall is reduced, less heat is lost within the duct, and a higher proportion (i.e., approximately 96%) of the grease may exit the duct. Grease that does condense and deposit on the duct surface may be easier to remove.

Thirdly, the surface properties of the coating can be well controlled using the described nozzle and duct coating device. Accordingly, consistent and desired surface properties of the coating can be achieved. Advantageous coating properties (such as a consistent and well controlled dimpled pattern) may contribute to the reduction of grease within the duct. The dimpled surface of the coating reduces airflow resistance and allows for faster movement of air/grease through the duct and a higher proportion of the grease reaching the duct exit instead of depositing throughout the duct. Air turbulence, which can be caused by corners and curves in the ductwork, is also reduced.

In particular, when an electric motor is used as the actuation mechanism 700, the speed of rotation of the nozzle 100 can be more finely controlled, for example, as compared to an air-powered actuation mechanism. For example, rotation may be controlled to be slow enough such that the substance does not escape at the edge 510 of the side wall 500. For example, this may allow use of a nozzle 100 with a smaller height H. Overall, the ability to more finely control the rotation speed (for example, to be lower) may provide greater flexibility over the physical dimensions of the nozzle 100.

An electric motor may provide not just finer control over the magnitude of the rotational speed, but may also provide more consistent (e.g., substantially non varying) rotational speed during use. This may provide a consistent dimpled effect for the substance coating inside the duct.

An electric motor as the actuation mechanism 700 may provide less vibration (e.g., vibration of a consistent and/or smaller magnitude) as compared to an air-powered actuation mechanism 700. For example, less vibration during operation may contribute to a more consistent and/or the desired kind of dimpled pattern of the substance coating inside the duct.

Furthermore, an electric motor as the actuation mechanism 700 means that compressors and air powered engines are not required. This has the advantage of reducing the noise level during use of the device 1000 because compressors can reach decibel levels 75-90 dBA, and air powered engines can reach decibel levels of 75-95 dBA. Additionally, use of an electric motor eliminates the need for high-pressure hoses to be located through the building, which reduces safety risks during use of the device.

Additionally, use of a nozzle 100 and/or a duct coating device 1000 as provided for by the present disclosure prevents leaking connections within the extraction system. After an extraction system is shut down, condensed grease can leak through the connection points because the upwards push from the airflow has ceased. Coating the inside surface of the ducts forms a seal across these connection points.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

22 CLAIMS 1. A nozzle (100) configured to expel a substance to coat the inside of a duct, the nozzle (100) comprising: a substance cavity (200); a coupling portion (300) for connecting to an actuation mechanism (700) such that the actuation mechanism (700), when operated, causes the nozzle (100) to rotate about a rotation axis (Z); a side wall (500) comprising a plurality of slits (600); and an end portion (400) comprising an inner end surface (410) perpendicular to the rotation axis (Z), wherein: the substance cavity (200) is defined by the side wall (500) and the end portion (400); in use, rotation of the nozzle (100) causes the substance within the substance cavity (200) to be expelled through the plurality of slits (600) in a direction away from the rotation axis (Z); and each of the plurality of slits (600) is elongate, and each elongate slit (600) extends in a direction from an edge (510) of the side wall (500) toward the end portion (400) at a non-zero angle relative to the rotation axis (Z).
2. The nozzle (100) according to claim 1, wherein each of the plurality of slits (600) extends toward the end portion (400) at an angle of 45° relative to the rotation axis (Z).
3 The nozzle (100) according to any one of the preceding claims, wherein: the side wall (500) comprises an inward facing surface (502) having a non-zero angle with respect to the rotation axis (Z) such that a part of the inward facing surface (502) closest to the end portion (400) is closer to the rotation axis (Z) than another part of the inward facing surface (502) closest to the edge (510) of the side wall (500).
4. The nozzle (100) according to claim 3, wherein: the non-zero angle of the inward facing surface (502) with respect to the rotation axis (Z) is between 6° and 8°.
5. The nozzle (100) according to any preceding claim, wherein: the side wall (500) surrounds the rotation axis (Z) such that the plurality of slits (600) are positioned around the rotation axis (Z).
6. The nozzle (100) according to any preceding claim, wherein the plurality of slits (600) are spaced apart from one another by the same amount
7. The nozzle (100) according to any preceding claim, wherein: the side wall (500) defines a height (H) that extends from the edge (510) of the side wall (500) to the end portion (400) of the nozzle (100) and which is parallel to the rotation axis (Z), and each of the plurality of slits (600) is of a length and an inter-slit spacing is such that a portion of each slit of the plurality of slits (600) is arranged to overlap a portion of an adjacent slit of the plurality of slits (600) when viewed along the height (H) of the side wall (500).
8 The nozzle (100) according to claim 7, wherein: each of the plurality of slits (600) defines a width (VV), and the portion of each slit of the plurality of slits (600) arranged to overlap the portion of an adjacent slit of the plurality of slits (600) is equal to one half the width (VV) of said slit when viewed along the height (H) of the side wall (500).
9. The nozzle (100) according to claim 8, wherein the width (VV) of each of the plurality of slits (600) is 4 mm.
10. The nozzle (100) according to any preceding claim, wherein: the depth (D) of the substance cavity (200) along the rotation axis is between 30mm and 44 mm.
11. The nozzle (100) according to any preceding claim, wherein the nozzle (100) is formed of a material comprising polymer.
12. A duct coating device (1000) comprising: the nozzle (100) according to any one of the preceding claims; and an actuation mechanism (700) coupled to the coupling portion (300) of the nozzle (100), 30 wherein: the actuation mechanism (700) is configured to rotate the nozzle (100) about the rotation axis (Z).
13. The duct coating device (1000) according to claim 12, wherein: the actuation mechanism (700) is configured to rotate the nozzle (100) according to a set of rotation operations.
14. The duct coating device (1000) according to claim 12 or claim 13, wherein: the actuation mechanism (700) is configured to rotate the nozzle (100) at a circumferential speed of between 10 m/s to 15 m/s at an outer diameter of the nozzle (100).
15. The duct coating device (1000) according to any of claims 12 to 14, wherein: the actuation mechanism (700) is configured to rotate the nozzle (100) about the rotation axis (Z) in a first direction and in a second direction opposite to the first direction.
16. The duct coating device (1000) according to claim 15, wherein: the actuation mechanism (700) comprises an electric motor operable to cause the nozzle (100) to rotate in the first direction and in the second direction.