GB2056051A - A fluid deflecting assembly - Google Patents

Abstract

A fluid deflecting assembly comprises first and second opposing walls 2, 5, the former having a portion 3 curved to effect attachment of the outlet flow thereto and the latter having a substantially straight portion 6 and being provided with a ridge 7 at the upstream end thereof, and a control vane 11 positioned between the first and the second walls. The control vane 11 is able to rotate around its axis thereby attaining wide deflection of the outlet flow due to the existence of two attachment walls. The height and position of the ridge 7 is determined so as to help the vertical downward deflection of the outlet flow along the curved portion 3. The length and position of the straight portion 6 is determined so as to help the horizontal deflection of the outlet flow along the straight portion 6. <IMAGE>

Description

SPECIFICATION A fluid deflecting assembly The present invention generally relates to a fluid deflecting assembly which is able to deflect air flow widely and continuously using a control vane. In this invention, the air flow is deflected from the horizontal to a substantially vertically downward direction using the attachment effect of fluid to a wall. For the downward deflection, a curved wall is used and for the horizontal, a substantially straight wall is used.

We are able to attain not only wide deflection flow but also two widely divided flows, one of which is directed in a downward direction and the other is directed in a horizontal direction by using two walls at the same time. We can thus select one of several flow patterns according to the inclination of a control vane.

A previously proposed deflecting assembly is shown in U.K. Patent Application No. 32551/78.

In this case, the directing means, which is constituted by an L-shaped beam, is employed in the upper part of the fluid deflecting assembly and located downstream of a deflecting blade.

Furthermore, there is no attachment wall having a straight portion on the downstream side of the directing means. Accordingly, horizontal air flow is rather difficult to attain and moreover, a flow pattern having two divided flows cannot be realized.

The same thing can also be said with regard to U.S. Patent No. 2,812,980, which additionally does not have a control means such as the deflecting blade employed in the embodiment of our invention which will be described later.

The present invention provides a fluid flow deflecting assembly comprising: first and second opposite walls defining therebetween a flow passage, the first wall having a curved guide portion; the second wall having a substantially straight guide portion with a ridge intermediate the ends of said flow passage; a rotatable control vane disposed in the flow passage and being able to rotate around said shaft to control the direction of an outlet fluid flow and to divide said outlet fluid flow into two flows, a first of which is defined by fluid flowing between said first wall and said control vane and a second of which is defined by fluid flowing between said second wall and said control vane; said control vane being disposed so as to be able to control the attachment effect caused by the interaction between said first fluid flow and said curved guide portion; said ridge being so located and arranged as to deflect said second flow toward said first flow which is attached to said curved guide portion when said outlet flow is desired to be long said curved guide wall and not to intercept the attachment effect of said second flow to said straight guide portion when said outlet flow is aimed at the direction along said second wall; said straight guide portion being sufficiently long to cause the attachment effect.

In use, the assembly can deflect an air flow through a large angle and continuously from a horizontal to a vertically downward direction Preferably, the fluid flow is divided into two separate flows using the two walls as the attachment walls at the same time.

Advantageously, the flow rate loss is decreased by arranging the ridge upstream of the downstream edge of a control vane.

A step is preferably provided in the first wall in order to make sure the deflecting operation in a horizontal direction is achieved without causing an attachment effect to the curved guide portion.

The shape of the control vane may be altered to increase the angle of deflection of the outlet flow.

To this end, the control vane may have a bend adjacent its downstream edge. Also, in order to obtain a flow pattern of two divided flows a control vane may be used which has a crosssectional thickness with its outer radius being smaller than its inner radius.

In order that the present invention be more readily understood, embodiments thereof will now be described by way of example with reference to the accompanying drawings, in which: Figure 1. is a perspective view of a fluid deflecting assembly according to one preferred embodiment of the present invention; Figure 2 is a cross-sectional view of the fluid deflecting assembly, taken along the line I-I' in Figure 1, wherein Figures 2(a), 2(b), 2(c) and 2(d) show the flow patterns with the control vane positioned at different operative positions; Figure 3 illustrates a further preferred embodiment of the present invention, wherein Figures 3(a), 3(b) and 3(c) are schematic sectional views of the fluid deflecting assembly with the control vane positioned at different operative positions;; Figure 4 illustrates a further preferred embodiment of the present invention, wherein Figures 4(a) and 4(b) are schematic sectional views of the fluid deflecting assembly with the control vane positioned at different operative positions; Figure 5 is a side sectional view of the control vane of the fluid deflecting assembly according to a further preferred embodiment of the present invention; and Figures 6(a) and 6(b) are schematic sectional views of the fluid deflecting assembly employing the control vane shown in Figure 5 with the control vane positioned at different operative positions.

It is to be noted that in the following description and drawings like parts are designated by like reference numerals. It is also to be noted that, although the term "fluid" hereinbefore and hereinafter referred to as a driving fluid by which the fluid deflecting assembly of the present invention operates, is intended to include gas and liquid, the following detailed description will be made with air as the driving fluid for the purpose of facilitating a better understanding of the present invention.

Referring now to Figures 1 to 2, a fluid deflecting assembly is generally indicated by reference numeral 1, and comprises a lower wall having an upstream portion 2 followed by a curved guide portion 3 with a step or setback 4 at the junction between the two portions and an upper wall having an upstream portion 5 followed by a substantially straight guide portion 6 with a ridge 7 at the junction between the two portions.

The fluid deflecting assembly 1 also has side panels 8 and 9.

The upper and lower upstream walls are attached to the side panels 8 and 9 as shown in Figure 1 in any known manner, to constitute a fluid passage 10 in the fluid deflecting assembly 1.

A control vane 11 having an elongate rectangular cross-section extends between the side panels 8 and 9 and traverses the fluid passage 10. This control vane 11 is carried by a shaft 12 having its opposed ends journalled to the side panels 8 and 9, and is positioned immediately above the step 4.

Although not shown, one end of the shaft 12 is in turn coupled through a suitable transmission system to a drive mechanism, which may comprise a manually operable switching knob and an electrically operated motor, so that the control vane 11 can be pivoted about the shaft 12, either adjustably or continuously, depending upon the type of the drive mechanism.

The control vane 11 divides the flow passing through the passage 10 into two flows, one of which is a lower flow (the first flow) between the curved guide portion 3 and the control vane 11 and the other is an upper flow (the second flow) between the straight guide portion 6 and the control vane 11.

The ridge 7 is designed in its position and height to deflect the upper flow downwards when it is desired to have a vertically downward outlet flow but not to prevent the upper flow from causing attachment to the straight guide wall 6 when it is desired to have a horizontal outlet flow.

The length of the straight guide section 6 is such that it is long enough for the upper flow to exhibit the attachment effect when the upper flow is horizontal. Accordingly, the ridge 7 is located upstream of the downstream edge 14 of the control vane 11. Due to this location of the ridge 7, the height of the ridge 7 is smaller than the conventional directing means as is shown in U.K.

Patent Application No. 32551/78 filed on August 8,1978.

The lower upstream portion 2 is arranged in almost the same direction as the tangential direction at the upstream end of the curved guide portion 3 in order to deflect the lower flow easily toward the curved guide portion 3.

The step 4 is formed to prevent the lower flow from exhibiting the attachment effect to the curved guide portion 3 when the outlet flow is supposed to be horizontal.

In Figure 2(a), the control vane 11 is inclined slightly upwards, i.e. the edge 14 is above the axis of the vane 11, as designated by an angle, (r. In this condition, the upper flow, C1, is directed in a downward direction because of the existence of the ridge 7, however, it attaches to the straight guide portion 6 due to the interaction between the upper flow, c1, and the straight guide portion 6 in addition to the influence of the inclination of the control vane 11. On the other hand, the lower flow, b,, separates from the lower wall due to the existence of the step 4 and does not attach to the curved guide portion 3. As a consequence, the outlet flow, d1, is horizontal.

In Figure 2(b), the control vane 11 is inclined slightly downwards as designated by an angle, /).

In-this case, the lower flow, b2, is directed in an oblique downwards direction due to the inclination of the control vane 11 and attachment effect of the flow to the curved guide portion 3.

However, the lower flow, b2, detaches from the curved guide portion 3 after only a portion of the length of the curved guide portion 3, because the inclination angle, /:, is small. On the other hand, the upper flow, c2, is directed in a downward direction due to the influence of the ridge 7. There is no tendency for the upper flow to be directed in an upward direction, therefore, the upper flow does not attach to the straight guide portion 6, but flows along the control vane 11. Accordingly, there is a single outlet flow directed in an obliquely downwards direction.

In Figure 2(c), the control vane 11 is more angled as designated by an angle, r, than in Figure 2(b). The lower flow, b3, remains attached to the curved guide portion 3 almost to the end thereof due to the large inclination of the control vane 11 and the separation distance w, between the vane 11 and the portion 3 which is smaller than that in the case of Figure 2(b) and forms a nozzle. It is to be noted that, the deflection angle of the lower flow generally increases according to the decrease of the distance w. The upper flow, C3, is also directed in a downward direction for the same reasons as given in relation to Figure 2(b), and flows along the control vane 11. There is also some induction effect due to-the lower flow, b2.

Accordingly, there is a single outlet flow directed in a downward direction.

In Figure 2(d), the control vane 11 is inclined at an even larger downward direction as designated by an angle, .S. Although the lower flow, b4, attaches to the curved guide portion 3, the upper flow, C4, cannot be induced by the lower flow, b4, because the control vane 11 separates the two flows, b4 and c4 due to its large angle of inclination and the small momentum of the lower flow, b4, is not enough to cause an induction effect on the upper flow, C4. Therefore, the upper flow, C4, attaches to the straight guide wall 6, in spite of the existence of the ridge 7. Accordingly, the outlet flow is divided into two flows which are widely separated from each other.

As stated before, the lower upstream portion 2 is directed in the same direction as the tangential direction at the upstream end of the curved guide portion 3, therefore, the attachment effect of the lower flow to the curved guide portion 3 occurs easily. There is no need for the upper flow to act on the lower flow in order to intensify the attachment effect of the lower flow to the curved guide portion 3. As a consequence, the height of the ridge 7 can be rather small, which means that the flow resistance of the ridge 7 is small.

As shown in Figure 2(a), the ridge 7 should be located at a point upstream of the downstream end 14 of the control vane 1 That is to say, in order to attain the attachment effect of the upper flow to the straight guide wall 6, the directional restriction of the control vane 11 should be effected downstream of the ridge 7. This location of the ridge 7 does not necessarily weaken the deflecting effect of the ridge 7 on the upper flow in the case of Figure 2(b) or 2(c), because the role of the ridge 7 is merely to make the upper flow deflect towards and flow along the control vane 11. Furthermore, the deflecting effect of the ridge 7 is larger the more upstream it is placed with respect to the edge 14 of the vane 11.

As mentioned above, we are able to attain wide and continuous deflection of the outlet flow, as well as to divide the outlet into two flows, merely by a change in the angle of inclination of the control vane 11.

Due to the existence of a continuous shift of the point of detachment of the lower flow from the portion 3 according to the control vane inclination, the outlet flow can be deflected continuously at any desired direction.

The control vane 11 of the fluid deflecting assembly can be made of various cross-sectional shapes as illustrated in Figures 3 to 6.

In Figure 3, a control vane 11' is employed instead of the control vane 11 in Figure 2.

Upstream and downstream ends of the control vane 11' are designated by 13' and 14' respectively. This embodiment is designed so as to attain enhanced operation in deflecting the outlet flow in a downward direction.

In Figure 3(a), the inclination of the control vane 11' represented by the straight line drawn from the shaft 12 to the downstream end 14' of the control vane 11' is defined by an angle 1 ' relative to the horizontal line. When assuming that Z = i', the lower flow, b5, is directed in a more downward direction, compared with the lower flow, b4, in the case of Figure 2(c), because of the curvature of the control vane 11 '. Therefore, the lower flow, b5, is attached to the curved guide portion 3, to a portion further downstream as compared with the case of the flat control vane 11 shown in Figure 2(c).On the other hand, the upper flow, c5, changes its direction smoothly and easily because of the curvature of the upper surface of the control vane 1 1'. Accordingly, the outlet flow, d5, is directed in a more downward direction in comparison with the direction of the outlet flow using the flat control vane 11. Furthermore, the curvature of the control vane 11' contributes to a decrease in the flow resistance due to the fact that both flows, b5 and c5, experience directional change gradually, compared with the case of using flat control vane 11.

In Figure 3(b), the upper flow, c6, flows along the curvature of the control vane 11' and tends to flow very slightly in a downward direction at the downstream end 14' of the control vane 11 However, the upper flow, c6, interacts with and attaches to the straight guide wall 6 joining with the lower flow, b6, thereby attaining a horizontally directed outlet flow, d6.

Thus, we are able to attain a greater angle of deflection of the outlet flow, from horizontal to a substantially vertically downward direction, with less flow resistance by using the curved control vane 11'.

In Figure 4, a curved control vane 11" having a bend 1 7 at its downstream end, is employed instead of the smoothly curved control vane 11' shown in Figure 3. Upstream and downstream ends of the control vane 11" are designated by 13" and 14" respectively. This embodiment is also designed so as to attain enhanced operation in deflecting the outlet flow in a downward direction.

In Figure 4(a), the lower flow, b7, is directed in a more downward direction by the effect of the bend 17. Furthermore, the separation distance w' is decreased due to the existence of the bend 1 7, as compared with the case of Figure 3(a), wherein no bend is employed. Due to the above mentioned two conditions, the attachment effect prevails further downstream on the curved guide portion 3.

Although the upper flow, c7, detaches from the control vane 11" at the beginning of the bend 17, it is induced by the firmly attached lower flow, b7.

Accordingly, the outlet flow, d7, is deflected in a more downward direction than that in the case of using the control vane without bend.

In Figure 4(b), the upper flow, c8, flows along the curvature of the control vane 11", and detaches easily from the surface of the control vane 11" due to the existence of the bend 14".

Therefore, the attachment effect of the upper flow, c8, to the straight guide portion 6 occurs more easily in this case than in that of Figure 3, wherein no bend is employed. The direction of the lower flow, b8, is induced by the upper flow, c8, thereby attaining the horizontally directed outlet flow, d8.

As stated above, we are able to attain a greater angle of deflection of the outlet flow in comparison with the case of Figure 3.

Referring to Figures 5 and 6, a control vane 1 8 has a thickness in its cross-section which is defined by an outer radius, r, and an inner radius, R, the former forming an outer surface 19 and the latter forming an inner surface 20, as shown in Figure 5. The radius r is chosen so as not only to minimize the flow resistance in attaining the flow pattern shown in Figure 6(a), but also to prevent the upper flow from separating from the outer surface 1 9 of the control vane 1 8 in attaining the flow pattern shown in Figure 6(c). The radius R is chosen so as not only to deflect the lower flow direction smoothly in attaining the flow pattern shown in Figure 6(c), but also easily to cause negative pressure in the region between the lower flow and the control vane 1 8 in attaining the flow pattern shown in Figure 6(b).

In Figure 6(a), the control vane 18 is inclined upwardly at a large angle of 0, relative to the horizontal direction, thereby splitting the inlet flow, a9, into two flows, b9 and cg. The lower flow, bg, is directed along the lower part of the outer surface 1 9 of the control vane 1 8 and attaches to the curved guide portion 3 as shown in Figure 6(a). On the other hand, the upper flow, cg, is directed along the upper part of the outer surface 19 of the control vane 1 8 and attaches to the straight guide portion 6 as shown in Figure 6(a) because the downstream end 14"' of the control vane 18 is located downstream of the ridge 7.

Thus, the inlet flow, a9, is divided into two flows which are widely separated from each other.

In Figure 6(b), the angle of inclination is decreased to ()2' which is the position for attaining a horizontally directed outlet flow. The upper flow, c1O, flows along the outer surface 1 9 and attaches to the straight guide wall 6, because the ridge 7 is located further upstream of the downstream end 13"' of the control vane 1 8. On the other hand, the lower flow, b10, separates at the upstream end 1 3"' of the control vane 1 8 and joins the upper flow, c1O, with the help of negative pressure caused due to the shape of the inner surface 20 of the control vane 1 8. Accordingly, the outlet flow, d10, is directed in a horizontal direction.

In Figure 6(c), the control vane 18 is inclined in a downward direction at an angle of O3 relative to the horizontal direction for the purpose of deflecting the outlet flow in a vertically downward direction. The lower flow, b1l, flows along the inner surface 20 of the control vane 1 8, gradually changing its direction, thereby maintaining the attachment effect to the curved guide portion 3 until its downstream end. On the other hand, the upper flow, c1l, flows along the outer surface 19 of the control vane 1 8 with the aid of the deflection effect caused by the ridge 7, which is located upstream of the downstream end 14"' of the control vane 1 8. Accordingly, the outlet flow, d1l, is directed in a substantially vertically downward direction.

As mentioned hereinbefore, we are able to attain a flow pattern divided into two flows with less flow resistance by using the control vane having different values for its outer and inner radius without influencing the deflecting operation of the outlet flow from horizontal to downward direction.

It is to be noted that, in the case of Figure 2, the flow pattern with two divided flows is realized successively after the downward deflecting flow pattern as shown in Figure 2(c), by turning the shaft 12 in a counterwise direction. In contrast, in the case of Figure 6, the flow pattern with two divided flows is realized successively after the horizontally deflecting flow pattern as shown in Figure 6(b), by turning the shaft 12 in a clockwise direction.

While the invention has been particularly shown and described with reference to several specific embodiments, it will be clear that various modifications can be made in construction and arrangement.

Claims (10)

1. A fluid flow deflecting assembly comprising: first and second opposite walls defining therebetween a flow passage, the first wall having a curved guide portion; the second wall having a substantially straight guide portion with a ridge intermediate the ends of said flow passage; a rotatable control vane disposed in the flow passage and being able to rotate around said shaft to control the direction of an outlet fluid flow and to divide said outlet fluid flow into two flows, a first of which is defined by fluid flowing between said first wall and said control vane and a second of which is defined by fluid flowing between said second wall and said control vane; said control vane being disposed so as to be able to control the attachment effect caused by the interaction between said first fluid flow and said curved guide portion; said ridge being so located and arranged as to deflect said second flow toward said first flow which is attached to said curved guide portion when said outlet flow is desired to be along said curved guide wall and not to intercept the attachment effect of said second flow to said straight guide portion when said outlet flow is aimed at the direction along said second wall; said straight guide portion being sufficiently long to cause the attachment effect.

2. A fluid deflecting assembly as claimed in claim 1, wherein said curved guide portion and said control vane are shaped and arranged relative to each other so as to control the attachment effect of said outlet flow to the curved guide wall to cause continuous deflection.

3. A fluid deflecting assembly as claimed in claim 1 or 2, wherein said control vane is shaped and arranged so as to divide said outlet flow into two flows, each of which exhibit an attachment effect to said curved guide portion and said straight guide portion respectively at the same time when said outlet flow is desired to be divided into two separate flows.

4. A fluid deflecting assembly as claimed in claim 1, 2 or 3, wherein said first wall has a step at the upstream end of said curved guide portion to prevent said first flow from being attached to said curved guide wail when it is desired to have the outlet flow parallel to the second wall.

5. A fluid deflecting assembly as claimed in any one of the preceding claims, wherein said control vane is a flat plate.

6. A fluid deflecting assembly as claimed in any one of claims 1 to 4, wherein said control vane has a curved cross-sectional shape.

7. A fluid deflecting assembly as claimed in claim 6, wherein said control vane has a bend adjacent its downstream edge.

8. A fluid deflecting assembly as claimed in claim 6, wherein said control vane is of a curved shape having thickness with its outer radius of curvature being smaller than its inner radius of curvature.

9. A fluid deflecting assembly according to claim 1, wherein the first wall comprises a straight portion upstream of said curved guide wall portion and separated therefrom by a curved guide wall step, said upstream straight portion being arranged parallel to the tangential direction of said curved guide portion at its upstream end.

10. A fluid deflecting assembly as claimed in claim 9, wherein the assembly is mounted with its first wall below its second wall directing the outlet flow in the vertically downward and the horizontal directions respectively.

1 A fluid deflecting assembly substantially as hereinbefore described with reference to the accompanying drawings.