Collection devices

Abstract: In more detail the apparatus comprises a duct for transporting material entrained in a stream of pressurised primary air from a collection mouth at an upstream end of the duct to a downstream region of the duct for collection. at least one primary air inlet opening into the duct for delivering pressurised air to form a primary air stream directed generally downstream of the duct, at least one secondary air outlet for delivering pressurised air to form a secondary air stream directed onto an area of the surface confronting the collection mouth, the secondary air stream serving to dislodge material on the said confronting area for entrainment in the primary air stream and transportation from the collection mouth to the downstream region of the duct for collection.

Description: This invention relates to an apparatus for collecting material from a surface. Various forms of collection apparatus have been proposed for collecting material under suction - so called vacuum cleaners for domestic use - as well as suction cleaners for collecting material and refuse from streets, gardens etc. EP0443882 discloses a collection device comprising an elongate duct for conveying loose material towards a downstream region thereof from a collection mouth at an upstream end thereof. An air outlet is disposed adjacent the collection mouth and arranged to, in use, direct an air flow transversely to the longitudinal axis of the duct over a curved, generally convex flow control surface of the collection mouth, such that at least a portion of said air flow follows said curved surface and is directed downstream within said duct. A controllable air flow outlet is provided so as to allow a flow of air to be directed out from the collection device, as and when desired. A slidable flap is provided which can be moved to open the air flow outlet thereby providing a flow of air away from the collection head of the collection device which can be used to blow debris such as leaves into a corner prior to collection. US4018483 discloses an apparatus for dislodging and conveying material from a surface and into a discharge duct with a positive pressure, high velocity stream of fluid from a jet device. CH-474623 discloses a collection device in which debris is sucked from a surface through a tube, and air is directed under pressure towards the surface in order to entrain debris from the surface prior to being sucked through the duct. It is an object of the present invention to produce a collection device operable upon a suction principal and including one or more jets of pressure air for dislodging material from a surface to assist in the collection thereof. According to the present invention, an apparatus for collecting material from a surface comprises a duct for directing material entrained in a stream of pressurised air from a collection mouth at an upstream end of the duct to a downstream region of the duct for collection; at least one primary air inlet opening into the duct for delivering pressurised air into the duct in a generally downstream direction to form a primary air stream, the delivery of the primary air stream into the duct inducing a flow of ambient air into the duct through the collection mouth, the flow of ambient air serving to entrain material from the surface and transport the material from the collection mouth to the downstream region for collection, at least one secondary air outlet for delivering pressurised air externally of the apparatus to form a first stream of secondary air directed onto an area of the surface confronting the collection mouth, the first stream of secondary air stream serving to dislodge material disposed on the said confronting area for entrainment in the flow of ambient air, at least one additional secondary air outlet disposed to direct a second stream of secondary air externally of the apparatus towards the surface at a position displaced from the area of the surface confronting the collection mouth; and a control valve for selectively controlling flow of primary and secondary air from: (i) the primary air inlet; (ii) the secondary air outlet; and (iii) the additional secondary air outlet, the control valve having a first operating position in which pressurised air is permitted to flow through at least the primary air inlet while disabling the flow of pressurised air through the additional secondary air outlet, and a second operating position in which pressurised air is permitted to flow through the additional secondary air outlet while disabling the flow of pressurised air through the primary air inlet. It is preferred that the control valve selectively control the flow of primary and secondary air such that the flow of secondary air from the additional secondary air outlet is disabled when the control valve is operated to select the primary air inlet independently of the secondary air outlet, or the primary air inlet together with the secondary air outlet. In certain embodiments, the control valve comprises a segment of a cylinder having an axis of rotation, the segment mounted for angular displacement about said axis of rotation and movable between positions in which selected air outlets are open or closed. Preferably, said additional secondary air outlet is shaped to direct pressure air away from the apparatus and at an obtuse angle relative to the stream of primary air flowing downstream within the duct. The secondary air outlet is preferably shaped to direct secondary air at an acute angle relative to the confronting area of the said surface to dislodged material on the said area. Apparatus according to the present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a longitudinal cross-section of a first form of apparatus with a control valve in a first position for using the apparatus in a suction mode; Figure 2 is a longitudinal section of a part of Figure 1 with the control valve in a second position for using the apparatus in a blow mode, and Figure 3 is a longitudinal section, similar to Figure 2 showing a second form of apparatus. Figure 1 shows the apparatus in an "in use" position relative to a surface S from which material is to be collected. The apparatus has a duct D, a plenum chamber P and a fan F driven by an electric motor M for creating a source of pressure air. Air is drawn into the apparatus through apertures A and air under pressure is directed into the plenum chamber P as indicated by arrows PA. Air passes under pressure from the plenum chamber P into the duct D through a primary inlet I located at the upstream end of the duct D to create a primary stream of air which flows downstream in the direction of arrows DA. In order to assist the flow of pressure air from the plenum chamber P into the duct D via the inlet I, walls P1 and D2 of the plenum chamber and the duct are interconnected by a smooth U-shaped wall U. A collection container (not shown) is connectable to downstream end DS of the duct D. The duct D has a collection mouth CM disposed in a plane inclined as indicated in Figure 1 relative to the longitudinal extent of the duct D. A control valve V having a wall V1 in the form of a segment of a cylinder is angularly movable about an axis X between a position shown in Figure 1 in which the inlet I is fully open to allow the primary stream of air to pass from the plenum chamber P into the duct D and a position shown in Figure 2 in which the inlet I is closed except for the secondary outlet S0. In the position shown in Figure 2 pressure air exits from the plenum chamber P through an additional secondary inlet S02. The secondary outlet SO is in the form of a narrow slot and in the position shown in Figure 1 is disposed adjacent to the collection mouth CM. The secondary outlet SO directs a relatively narrow and concentrated jet of air across the collection mouth CM and downwardly towards the surface S. In operation, and with the valve V in the position shown in Figure 1, the primary stream of pressurised air flowing through the duct D produces a negative pressure in the region of the collection mouth and the surface S inducing a flow of ambient air indicated, by arrows Z thereby drawing material to be collected from the surface SO. Material from the surface S is tlius entrained in the primary air stream, transported downstream in the duct D and into a collection container. The concentrated jet of air from the secondary outlet SO impinges on the surface S at an acute angle and serves to dislodge material on the surface prior to being picked up and entrained in the primary air stream. When the valve V is moved into the position shown in Figure 2, the inlet I is effectively closed and pressure air exits through the additionial secondary outlet SO2. In this condition, the apparatus may be used to blow material to be collected from the surface S into a pile and, in ordcr to collect the pile of material, the valve V is simply changed into the position shown in Figure 1. The valve V may be operated, electrically or manually in a manner known to those skilled in the art. Referring to Figure 3 in which like components are designated with the same reference numbers used in Figures 1 and 2, the second form of apparatus is illustrated including a modified secondary outlet and control valve arrangement. A curved wall V2 in the form of a segment of a regular cylinder is located between two supports S1 (of which only one is shown) carried on opposite side walls of the plenum chamber. A further curved wall V1 corresponding to the wall V1 of the valve shown in Figures 1 and 2 also in the form of a segment of a regular cylinder is mounted for angular movement about its axis of symmetry X. The wall V1 has three grooves G1, G2 G3 and angular movement thereof can be constrained in three separate positions when the respective grooves G1, G2, G3 are in engagement with a projection Y on the wall V2. It will be appreciated, that in a similar manner to operation of the apparatus of Figures 1 and 2 angular movement of the wall V1 serves to 1) open inlet I, open secondary outlet SO and close additional secondary outlet S02. See Figure 3 when projection Y in engagement with groove G3. 2) open inlet I and close both outlets SO and SO2 when the projection Y is engaged with slot G2, and 3) close inlet I, close outlet SO and open outlet SO2 when projection Y is in engagement with groove G1. In operation with inlet I and secondary outlet SO both open and outlet SO2 closed, the primary air stream flowing in the duct D produces a negative pressure in the region of the collection mouth CM creating an induced flow of ambient air indicated by arrows Z. Material on the surface S is lifted from the surface S by the flow of pressurised air entrained therein and transported downstream of the duct D for collection. A secondary stream of air issuing from the secondary outlet SO is, (as shown in Figure 3) directed at an acute angle to the surface S and serves to dislodge material on the surface and thereby assist pick-tip, entrainment and subscqueiit transportation of the material for collection. Although reference has been made to the use of a single source of pressure air, if desired, separate sources of pressure air may be uscd for the primary and secondary air flows. Further, to assist dislodging material which has a tendency to adhere to the surface S, a pulsating secondary air stream may be used. Pulsating of the secondary air stream may be produced by a rotatable paddle wheel not shown mounted in the region of the outlet SO. Alternatively, pulsation may be caused by mounting a thin plate in slots affording freedom of movement to the plate and formed in the sidewalls of the apparatus. The plate is disposed longitudinally of the outlet SO and is displaced outwardly therefrom in the direction of flow of the secondary stream of pressurised air. The freedom of movement of the plate in the slots affords considerable clearance to the thin plate permitting a pulsating movement in the direction of flow of the secondary air stream.

Claims: Apparatus for collecting material from a surface, the apparatus comprising: a duct (D) for directing material entrained in a stream of pressurised air from a collection mouth (CM) at an upstream end of the duct (D) to a downstream region (DS) of the duct (D) for collection; at least one primary air inlet (I) opening into the duct (D) for delivering pressurised air into the duct (D) in a generally downstream direction to form a primary air stream, the delivery of the primary air stream into the duct (D) inducing a flow of ambient air into the duct through the collection mouth (CM), the flow of ambient air serving to entrain material from the surface and transport the material from the collection mouth (CM) to the downstream region (DS) for collection, at least one secondary air outlet (SO) for delivering pressurised air externally of the apparatus to form a first stream of secondary air directed onto an area of the surface confronting the collection mouth (CM), the first stream of secondary air serving to dislodge material disposed on the said confronting area for entrainment in the flow of ambient air, at least one additional secondary air outlet (SO2) disposed to direct a second stream of secondary air externally of the apparatus towards the surface at a position displaced from the area of the surface confronting the collection mouth (CM); and a control valve (V) for selectively controlling flow of primary and secondary air from: (i) the primary air inlet (I); (ii) the secondary air outlet (SO); and (iii) the additional secondary air outlet (SO2), the control valve (V) having a first operating position in which pressurised air is permitted to flow through at least the primary air inlet (I) while disabling the flow of pressurised air through the additional secondary air outlet (SO2), and a second operating position in which pressurised air is permitted to flow through the additional secondary air outlet (SO2) while disabling the flow of pressurised air through the primary air inlet (I). Apparatus according to claim 1 wherein the control valve (V) selectively controls the flow of primary and secondary air such that the flow of secondary air from the additional secondary air outlet (SO2) is disabled when the control valve (V) is operated to select the primary air inlet (I) independently of the secondary air outlet (SO), or the primary air inlet (I) together with the secondary air outlet (SO). Apparatus according to claim 1 or 2 wherein the control valve (V) comprises a segment of a cylinder having an axis of rotation (X), the segment mounted for angular displacement about said axis of rotation (X) and movable between positions in which selected air outlets are open or closed. Apparatus according to claim 1, 2 or 3 including a source of pressurized air (F) and means (P) for directing pressurized air to the air inlets and the air outlets. Apparatus according to claim 4 wherein the means for directing pressurized air from the said source to the primary air inlet (I) and the secondary air outlets (SO,SO2) includes a plenum chamber(P). Apparatus according to any preceding claim wherein said at least one additional secondary air outlet (SO2) is shaped to direct secondary air away from the apparatus and at an obtuse angle relative to the stream of primary air flowing downstream within the duct (D). Apparatus according to any preceding claim wherein said at least one secondary air outlet (SO) is shaped to direct secondary air at an acute angle relative to the confronting area of the said surface to dislodged material on the said area. Apparatus according to any preceding claim wherein said at least one secondary air outlet (SO) is disposed in the region of the collection mouth (CM). Apparatus according to any preceding claim wherein said at least one secondary air outlet (SO) is disposed in a peripheral region of the collection mouth (CM). Apparatus according to claim 9 wherein said at least one secondary outlet (SO) directs pressurized secondary air away from the collection mouth (CM) and at an acute angle relative to the area of the surface confronting the collection mouth (CM).

Inventors: DAVIES JOHN SAMUEL, TURNBULL KENNETH JAMES, DAVIES, JOHN SAMUEL, TURNBULL, KENNETH JAMES
Applicants: ELECTROLUX OUTDOOR PROD LTD, ELECTROLUX OUTDOOR PRODUCTS LIMITED
Application year: 1993
Main classification: A47L9
IPC codes: A47L5, B08B5, A47L9