Unidirectional flow pickup hood for street sweepers

• US 4,109,341 A
• Filed: 08/04/1977
• Issued: 08/29/1978
• Est. Priority Date: 02/05/1976
• Status: Expired due to Term

• Current Assignee: Johnston Sweepers Limited (Bucher Industries AG)
• Original Assignee: FMC Corporation
• Inventors: Hiszpanski, Jan A., Larsen, Gregory J.
• Primary Examiner(s): Moore, Christopher K.
• Application Number:
  US05/821,670
• Time in Patent Office: 390 Days
• Field of Search: 15/340, 15/345, 15/346
• US Class Current: 15/346
• CPC Class Codes: E01H 1/0872 with mechanical loosening or feeding instruments for the dirt to be removed pneumatically, e.g. brushes, scrapers brushing installations per se E01H1/02; other loosening devices per se E01H1/105

Abstract

The hood for an air recirculation type of street sweeper forms a single, unidirectional air flow duct from the air inlet line to the air return. The top wall of the hood is formed to provide an air stream deflector that slants downwardly in the direction of the air return line and accelerates the air stream to insure that all debris is entrained in the air stream as it leaves the hood.

Claims

1. In a debris pickup system for street sweepers or the like which comprises a vehicle carrying a hopper, blower means for withdrawing air from the hopper, a debris pickup hood having an air inlet line for receiving air from said blower means, and an air return line for delivering air and entrained debris from said hood to the hopper;

said hood extending laterally of the vehicle and comprising an elongate box like structure extending laterally of the vehicle, said air lines being connected adjacent opposite end portions of the hood;

the improvement in said hood wherein said hood has top, side and end walls, the interior of said hood cooperating with the swept surface to provide a duct-like air chamber which is substantially unobstructed along its length for chanelling the air from said blower means into a substantially unidirectional stream of air from said air inlet line to said air return line, the top wall of said duct-like chamber being inclined downwardly from a zone upstream of said air return line to the air return line to provide an air deflector for progressively accelerating said unidirectional stream of air and entrained debris as the air stream sweeps the surface and approaches said air return line.

2. The system of claim 1, wherein said duct-like chamber has parallel side walls, said air deflector gradually reducing the spacing of the top wall of the chamber from the swept surface by about 25%.

3. The system of claim 2, wherein the air return line end of said hood is formed with a baffle for smoothly deflecting the impinging air stream upwardly from the swept surface into said air return line.

4. The system of claim 3, wherein said baffle is formed to present a curved concave face to the impinging air stream.

5. The system of claim 4, wherein said baffle comprises a flexible flap for engaging the swept surface.

6. The system of claim 1, wherein said air deflector extends along about 25% of the total length of said duct-like chamber.

7. The system of claim 1, wherein said top wall of the chamber is substantially parallel to the swept surface from the air inlet line of the upstream end of said air deflector.

8. The system of claim 7, wherein the spacing of said air deflector from the swept surface of said air return line is about three-fourths of the spacing of said top wall of the chamber from said surface at the air inlet line.

9. The system of claim 8, wherein said duct-like chamber has side walls that are substantially parallel.

10. In a debris pickup system for street sweepers or the like which comprises a vehicle carrying a debris hopper, a debris pickup hood comprising a duct-like structure extending transversely of the vehicle and having surface engaging flaps, said hood having an air inlet line opening thereinto near one end, an air return line opening into said hood near the other end and connected to the hopper, and blower means for withdrawing air from the hopper and delivering air to the hood inlet line;

the improvement in said hood wherein the interior of said hood cooperates with the swept surface to provide a duct-like air chamber which is substantially unobstructed along its length for channelling the air from said blower means into a substantially unidirectional stream of air from said air inlet line to said air return line, said stream of air sweeping the surface and entraining debris for delivery to the hopper via said air return line, the air return line end of said hood being formed with a baffle comprising a flexible flap for engaging the swept surface and formed to present a curved concave face to the impinging air stream, for smoothly deflecting the stream upwardly from the swept surface into said air return line, said duct-like hood chamber having an upper wall and side walls, the upper wall of said chamber comprising air deflecting means, said air deflecting means slanting downwardly from a zone upstream of said air return line to the air return line, said air deflecting means gradually accelerating the stream of air flowing toward said air return line for maintaining the entrainment of debris particles by the air stream until the air stream and entrained particles flow up into the air return line.

11. In a debris pickup system for street sweepers of the like which comprises a vehicle carrying a debris hopper, a debris pickup hood comprising a duct-like structure extending transversely of the vehicle and having surface engaging flaps, said hood having an air inlet duct opening thereinto near one end, an air outlet line opening into said hood near the other end and connected to the hopper, and blower means for withdrawing air from the hopper;

the improvement in said hood wherein the interior of said hood cooperates with the swept surface to provide a duct-like air chamber which is substantially unobstructed along its length for chanelling the air from said air inlet duct into a substantially unidirectional stream of air from said air inlet duct to said air outlet line, said stream of air sweeping the surface and entraining debris for delivery to the hopper via said air outlet line, the air outlet line end of said hood being formed with a baffle formed to present a curved concave face to the impinging air stream, for smoothly deflecting the stream upwardly from the swept surface into said air outlet line, said ductlike hood chamber having an upper wall and side walls, the upper wall of said chamber comprising air deflecting means, said air deflecting means slanting downwardly from a zone upstream of said air outlet line to the air outlet line, said air deflecting means gradually accelerating the stream of air flowing toward said air outlet line for maintaining the entrainment of debris particles by the air stream until the air stream and entrained particles flow up into the air outlet line.

12. In a debris pickup system for street sweepers or the like which comprises a vehicle carrying a hopper, blower means for withdrawing air from the hopper, a debris pickup hood having an air inlet duct, and an air outlet line for delivering air and entrained debris from said hood to the hopper;

said hood extending laterally of the vehicle and comprising an elongate box-like structure extending laterally of the vehicle, said air inlet duct and said air outlet line being connected adjacent opposite end portions of the hood;

the improvement in said hood wherein said hood has top, side and end walls, the interior of said hood coperating with the swept surface to provide a duct-like air chamber which is substantially unobstructed along its length for chanelling the air from said inlet duct into a substantially unidirectional stream of air from said air inlet duct to said air outlet line, the top wall of said duct-like chamber being inclined downwardly from a zone upstream of said air outlet line to the air outlet line to provide an air deflector for progressively accelerating said unidirectional stream of air and entrained debris as the air stream sweeps the surface and approaches said air outlet line.