Portable steam generating system

• US 6,393,212 B1
• Filed: 03/07/2001
• Issued: 05/21/2002
• Est. Priority Date: 03/18/1998
• Status: Expired due to Fees

• Current Assignee: Harwil Corporation
• Original Assignee: Harwil Corporation
• Inventors: Hutchinson, Harold D.
• Primary Examiner(s): Walberg, Teresa
• Assistant Examiner(s): CAMPBELL, THOR S
• Application Number:
  US09/801,240
• Time in Patent Office: 440 Days
• Field of Search: 392/491, 392/471, 392/465, 392/485
• US Class Current: 392/491
• CPC Class Codes: F04B 19/027 cylinders oscillating around an axis perpendicular to their own axis
• CPC Class Codes: F22B 1/285 the water being fed by a pump to the reservoirs

Abstract

A small portable steam generating system comprised of an elongate cylindrical cylinder having a turbulent baffle circulation system. The steam generator includes a plurality of baffles, having alternating ports spaced along the length of the cylinder. The baffles have ports offset at 180° respectively to each other to provide turbulent flow that speeds up and slows down as it passes through the ports. The series of baffles in the elongate cylinder are mounted around a centrally located heater. The surfaces and ports in the baffles, positioned along the elongate cylinder and heater body, form a diffused turbulent flow of variable length and time as it passes from an input to an output. The steam generating system described herein is fitted with a steam water droplet separation system plus a high pressure steam superheater fitted to an exit tube and a non-conductive high temperature tube for transporting super-heated steam to a surface cleaning applicator. The system uses a low flow capacity, high pressure pump to inject feed water into the steam generator. The system is controlled by a computer processing system which monitors water level, steam temperature, and pressure.

Claims

1. A fluid steam generating system comprising;

an elongate cylinder having an inlet and an outlet for circulating a fluid to be heated;

a heater in said elongate cylinder;

a flow circulator for circulating fluid around said heater to heat said fluid, said flow circulator comprising a plurality of baffles spaced apart along the internal length of said elongate cylinder, each of said plurality of baffles having one or more ports to direct the flow of fluid through said elongate cylinder and increase flow turbulence through said elongate cylinder, said ports in adjacent baffles being offset from each other to form an elongated turbulent flow path, said ports alternately causing formation of a series of converging high speed fluid jets followed by expansion into divergent low speed expansion chambers, said baffles having turbulent creating surfaces for creating a turbulent flow of fluid around said heater to increase flow path surface area; and

a pump for pumping said fluid into said inlet in said elongated internal container against an internal pressure head specifically created in said elongate container via a controlled exit control valve.

2. The system according to claim 1 in which said heater is a cylindrical electric heater located along the axis of said elongate cylinder.

3. The system according to claim 2 in which said heater is at least one loop heater mounted in said elongate cylinder.

4. The system according to claim 3 in which said at least one loop heater comprises a pair of loop heaters connected in series.

5. The system according to claim 4 in which said pair of loop heaters are normal to each other;

said cylindrical electric heater being packed with a thermally conductive electrical insulation.

6. The system according to claim 3 in which loop heater is mounted in a cylindrical heater tube thereby isolating loop heater surface from direct contact with working fluid.

7. The system according to claim 5 in which said loop heaters surface are isolated to prevent contact with working fluid thereby preventing micro surface boiling.

8. The system according to claim 5 in which said thermally conductive electrical insulator is magnesium oxide.

9. The system according to claim 8 including a temperature control for controlling the heater temperature and flow whereby microboiling at the surface of said heater is prevented by the turbulence caused by said baffles and scouring of the heater surface to minimize build-up of calcium on heater surfaces.

10. The system according to claim 8 in which said baffles are approximately equally spaced in said elongate cylinder dividing said elongate cylinder container into a plurality of chambers surrounding said electric heater.

11. The system according to claim 10 in which said orifices in adjacent baffles being offset from each other to increase residual time of fluid in the elongate cylinder.

12. The system according to claim 11 in which said orifices in adjacent baffles are offset approximately 180°

from one another whereby said fluid flows around said heater for maximum turbulent heat transfer.

13. The system according to claim 12 in which said baffles are equally spaced at intervals of approximately two inches.

14. The system according to claim 10 in which there are approximately six baffles per foot.

15. The system according to claim 14 in which said pump produces a flow of 0.001 to 1.0 gallons per minute through said elongate cylinder.

16. The system according to claim 15 including a controller for controlling the pump flow rate, the heater temperature and turbulence caused by said baffles to produce a temperature up to about 350°

F. of super-heated steam through said heating system.

17. The system according to claim 16 in which said control means is a central processing means that monitors pressure, temperature and flow rate.

18. The system according to claim 2 in which said elongate cylinder has a steam flow through volume of approximately 1.6×

10−

3 gallons under steady state conditions.

19. The system according to claim 17 in which said steam flow through volume is in the range of approximately 1.9×

10−

4 to 1.6×

10<sup>−

3</sup> gallons at about 200 psi and 350°

F. maximum.

20. The system according to claim 12 including a variable pressure control valve at said output to control steam pressure.

21. The system according to claim 20 in which steam temperature is controlled by said variable pressure control to be at a temperature of 350°

F. at approximately 200 psi.

22. The system according to claim 2 in which said elongate cylinder has a diameter and wall thickness selected to provide an internal pressure safety factor of better than nineteen.

23. The system according to claim 1 in which said pump is a low volume variable fluid injection pump having a low flow capacity of about 0.001 to 1.0 gallons per minute.

24. The system according to claim 23 in which said low volume pulse piston pump comprises;

a constant speed motor gear system;

a variable diameter eccentric arm connected to said constant speed motor gear system; and

a piston pump connected to said variable diameter eccentric arm.

25. The system according to claim 2 in which said cylindrical electric heater thermally isolates internal high temperature electric heaters from working fluid so as to minimize micro-boiling at the surface of said heater.

26. The system according to claim 20 in which said variable control valve is an open ended pressure control valve fitted with a variable orifice.

27. The system according to claim 26 in which said variable pressure control valve is adjustable between approximately 10 to 200 PSI.

28. The system according to claim 2 in which said pump means is a reciprocating piston pump;

and includes a piston pump drive motor.

29. The system according to claim 28 in which said piston pump drive motor is a variable linear stroke pump motor.

30. The system according to claim 28 in which said piston pump drive motor is a variable diameter piston pump motor.

31. The system according to claim 28 in which said pump drive motor is connected to said piston pump by an eccentric arm;

said eccentric arm having different radial positions for adjusting stroke length of said piston pump to said variable linear stroke pump motor.

32. The system according to claim 1 including means at said outlet to minimize water droplets in steam ejected from said outlet.

33. The system according to claim 32 in which said means for minimizing water droplets comprises an extension tube on said outlet extending the entrance to said outlet away from the interior surface of said elongate container.

34. The system according to claim 33 in which said extension tube has a termination configured to further minimizes water droplets entering said outlet.

35. The system according to claim 34 in which said termination configuration is a 180°

bend in said extension tube.

36. The system according to claim 34 in which said terminal configuration is a cone on the end of said extension tube.

37. The system according to claim 1 including a post heater for maintaining the temperature of steam super-heated steam from said elongate cylinder to an applicator tool.

38. The system according to claim 37 in which said post heater comprises heat conductive tubing wrapped around said elongate cylinder.

39. The system according to claim 38 in which said heat conductive tubing is copper tubing.

40. The system according to claim 39 in which said copper tubing is in a serpentine path parallel to the axis of said elongate cylinder.

41. The system according to claim 40 in which said copper tubing is connected at the exit of elongated cylinder to a high temperature plastic tube for transporting steam output for said steam generator to a steam cleaning applicator.

42. The system according to claim 41 in which said high temperature plastic tube is loosely fitted in a coaxial plastic insulating tube to reduce heat loss of transported steam from said elongated cylinder to a steam cleaning applicator.

43. The system according to claim 42 in which the outside diameter of said high temperature plastic tube is substantially less than the internal diameter of said coaxial plastic insulating tube.

44. The system according to claim 42 in which said coaxial plastic insulating tube is fitted with form fitting sections adjacent to said steam cleaning applicator to provide thermal protection of users hands during use.

45. The system according to claim 27 including a variable pressure control valve at the output of said post heater.

46. The system according to claim 45 in which variable pressure control valve is located as close as possible to the interface with a steam cleaning applicator to maintain the temperature of super-heated steam as long as possible.

47. The system according to claim 46 in which said variable pressure control valve is located in said steam cleaning applicator.