Claims
- 1. A heating system for the sole plate of a screed on a paving machine, comprising:
- a heat exchanger tube mounted directly in engagement with the upper surface of the sole plate;
- a pump;
- a flow reservoir;
- a flow restrictor; and
- a heating circuit connecting the heat exchange tube, reservoir, pump and flow restrictor so that liquid from the reservoir is pressurized by the pump to flow through the flow restrictor to the heat exchange tube and undergo a pressure drop at the flow restrictor resulting in heating of the fluid for heat transfer through the heat exchange tube to the sole plate.
- 2. A heating system according to claim 1 in which said heat exchange tube have a flat bottom surface engaging the upper surface of said sole plate.
- 3. A heating system according to claim 2 in which said heat exchange tube is rectangular in cross-section.
- 4. A heating system according to claim 1 in which said screed comprises two screed sections hinged together for relative up and down swinging movement, and there is a respective such heat exchange tube on each of said screed sections which are connected together for flow from one to the other.
- 5. A heating system according to claim 1 in which said pump is driven by a hydraulic motor, and in which said paving machine has a second reservoir, a second pump, and motor means for driving said second pump, and has a hydraulic circuit connecting said second reservoir, second pump, and hydraulic motor for operating said first-mentioned pump.
- 6. A heating system according to claim 5 in which said paving machine has a tractor coupled to said screed, and in which said second pump and motor means are mounted on said tractor, and said heating circuit is mounted on said screed.
- 7. A heating system according to claim 5 in which said screed has a vibratory unit driven by a second hydraulic motor in a vibratory circuit, and in which said hydraulic circuit includes a control valve for selectively operating said heating circuit or said vibratory circuit.
- 8. A screed for an asphalt paving machine comprising:
- a sole plate with a bottom sole surface and a top surface;
- means for flexing said sole plate;
- a heat exchange tube mounted directly onto said top surface for containing a liquid, said tube being adapted to flex with said sole plate; and
- means for heating a liquid and circulating the heated liquid through said heat exchange tube.
- 9. A screed according to claim 8 in which said sole plate and heat exchange tube are steel, and the heat exchange tube has a flat side seated on said top surface of the sole plate.
- 10. A screed according to claim 9 in which said heat exchange tube is spot welded to said sole plate.
- 11. Apparatus for a paving machine, comprising:
- a screed;
- means including a pump and a flow restrictor in series for circulating fluid under pressure through said flow restrictor to heat said fluid, and for circulating said heated fluid at reduced pressure through a tube which is in direct heat transfer relation to said screed for responsively heating the screed.
- 12. A combination heating system and vibratory system for a screed coupled to a tractor on an asphalt paving machine, comprising:
- a selector valve on the screed;
- a pressurized oil supply circuit to said selector valve from the tractor;
- a screed-heating hydraulic circuit on the screed connected to said selector valve; and
- a vibratory unit on the screed driven by a hydraulic motor in a vibratory hydraulic circuit connected to said selector valve;
- said selector valve being adapted to connect said supply circuit to said screed-heating circuit or to said vibratory circuit.
- 13. A combination according to claim 12 in which said screed-heating circuit includes a second hydraulic motor arranged to be operated by pressurized oil from said supply circuit, a high pressure pump driven by said second hydraulic motor, a flow restrictor arranged to cause a pressure drop in the output liquid from said high pressure pump to thereby heat the output liquid, and a heat exchange unit in direct heat exchange relationship with the sole plate of the screed for transferring heat from said heated output liquid to said sole plate.
- 14. A combination according to claim 13 which said heat exchange unit comprises a heat exchange tube mounted on said sole plate.
- 15. A screed unit for an asphalt paving machine comprising:
- two side-by-side frame units;
- a sole plate secured to said frame units and extending across the bottom of the screed unit beneath said frame units;
- two heat exchange tubes mounted on said sole plate beneath respective of said frame units for use in preheating said sole plates,
- and means for moving said frame units relative to one another to flex said sole plate,
- said heat exchange tubes being adapted to flex with said sole plate.
- 16. A screed unit according to claim 15 in which thermal insulation covers the top of said heat exchange tubes between said frame units and heat exchange tubes.
- 17. A screed unit for an asphalt paving machine comprising:
- a sole plate having front and back ends, two opposite lateral sides between said ends, an upper surface, and a bottom surface for engaging asphalt on a roadway;
- means for flexing one lateral side of said sole plate relative to the other lateral side thereof; and
- a heat exchange tube mounted in direct engagement with said upper surface of the sole plate and having a serpentine path on said upper surface.
- 18. A screed unit according to claim 17 in which said heat exchange tube is rectangular in cross-section and has one of its side faces seated against said upper surface of the sole plate.
- 19. A screed unit according to claim 18 in which said sole plate and heat exchange tube are steel, and said tube is weld-connected to the sole plate.
Parent Case Info
This application is a continuation-in-part of my copending U.S. patent application Ser. No. 07/577,615 dated Sep. 4, 1990 now U.S. Pat. No. 5,096,331.
US Referenced Citations (6)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
577615 |
Sep 1990 |
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