AIR COMPRESSOR

Abstract

A reciprocating piston air compressor has a first cylinder assembly, a second cylinder assembly, and a plurality intake valves and exhaust valves associated with each of the cylinder assemblies. Each cylinder assembly has a cylinder bore and a piston disposed in the cylinder bore. Each cylinder bore has a first end having a circumference defining an area. Each piston has a first end having a circumference defining an area. The valves associated with the first cylinder assembly are disposed within the circumference of the bore and/or the piston. The valves associated with the second cylinder assembly are disposed partially within and partially outside of the circumference of the bore and/or the piston.

Claims

1. A reciprocating piston air compressor, having: a first cylinder assembly having a first cylinder head, a first cylinder bore having a volume, a first piston disposed in the first cylinder bore, a surface disposed around the first cylinder bore and facing the first cylinder head, and a volume between the surface and the first cylinder head, the first cylinder bore having a first end facing the first cylinder head, the first end of the first cylinder bore having a circumference defining an area and the first piston having a first end facing the first cylinder head, the first end of the first piston having a circumference defining an area; at least first and second intake valves and at least first and second exhaust valves in the first cylinder head, the first and second intake valves and the first and second exhaust valves in the first cylinder head positioned above the first end of the first cylinder bore and within the circumference of the first end of the first cylinder bore; a second cylinder assembly having a second cylinder head, a second cylinder bore having a volume less than the volume of the first cylinder bore, a second piston disposed in the second cylinder bore, a surface disposed around the second cylinder bore and facing the second cylinder head, and a volume between the surface and the second cylinder head, the second cylinder bore having a first end facing the second cylinder head, the first end of the second cylinder bore having a circumference defining an area and the second piston having a first end facing the second cylinder head, the first end of the second piston having a circumference defining an area; and at least first and second intake valves and at least first and second exhaust valves in the second cylinder head, the first and second intake valves and the first and second exhaust valves in the second cylinder head positioned above the first end of the second cylinder bore partially within the circumference of the first end of the second cylinder bore and partially outside the circumference of the first end of the second cylinder bore.

2. The reciprocating piston air compressor according to claim 1, wherein between about 0.1% and about 5.0% of the surface area of the first and second intake valves and the first and second exhaust valves facing the first end of the second cylinder bore are positioned inside the circumference of the first end of the second cylinder bore.

3. The reciprocating piston air compressor according to claim 1, wherein the circumference of the first end of the first cylinder bore is smaller than the circumference of the first end of the second cylinder bore.

4. The reciprocating piston air compressor according to claim 1, wherein each of the first and second intake valves and the first and second exhaust valves in the first cylinder head has a valve element having a surface facing the first cylinder bore, and wherein the total area of the surfaces of the valve elements of the first and second intake valves and the first and second exhaust valves facing the first cylinder bore is between about 25% and about 85% of the area of the first end of the first piston.

5. The reciprocating piston air compressor according to claim 4, wherein the total area of the surfaces of the valve elements of the first and second intake valves and the first and second exhaust valves facing the first cylinder bore is about 73.37% of the area of the first end of the first piston.

6. The reciprocating piston air compressor according to claim 1, wherein each of the first and second intake valves and the first and second exhaust valves in the second cylinder head has a valve element having a surface facing the second cylinder bore, and wherein the total area of the surfaces of the valve elements of the first and second intake valves and the first and second exhaust valves facing the second cylinder bore is between about 25% and about 280% of the area of the first end of the second piston.

7. The reciprocating piston air compressor according to claim 6, wherein the total area of the surfaces of the valve elements of the first and second intake valves and the first and second exhaust valves facing the second cylinder bore is about 265% of the area of the first end of the second piston.

8. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the first cylinder head and the number of exhaust valves in the first cylinder head is the same.

9. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the first cylinder head is greater than the number of exhaust valves in the first cylinder head.

10. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the first cylinder head is less than the number of exhaust valves in the first cylinder head.

11. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the second cylinder head and the number of exhaust valves in the second cylinder head is the same.

12. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the second cylinder head is greater than the number of exhaust valves in the second cylinder head.

13. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the second cylinder head is less than the number of exhaust valves in the second cylinder head.

14. The reciprocating piston air compressor according to claim 1, wherein the total number of intake valves and exhaust valves in the first cylinder head is equal to the total number of intake valves and exhaust valves in the second cylinder head.

15. The reciprocating piston air compressor according to claim 1, wherein the total number of intake valves and exhaust valves in the first cylinder head is greater than the total number of intake valves and exhaust valves in the second cylinder head.

16. The reciprocating piston air compressor according to claim 1, wherein the total number of intake valves and exhaust valves in the first cylinder head is less than the total number of intake valves and exhaust valves in the second cylinder head.

17. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the first cylinder head is equal to the number of intake valves in the second cylinder head.

18. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the first cylinder head is greater than the number of intake valves in the second cylinder head.

19. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the first cylinder head is less than the number of intake valves in the second cylinder head.

20. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the first cylinder head is equal to the number of exhaust valves in the second cylinder head.

21. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the first cylinder head is greater than the number of exhaust valves in the second cylinder head.

22. The reciprocating piston air compressor according to claim 1, wherein the number of intake valves in the first cylinder head is less than the number of exhaust valves in the second cylinder head.

23. The reciprocating piston air compressor according to claim 1, wherein the number of exhaust valves in the first cylinder head is equal to the number of exhaust valves in the second cylinder head.

24. The reciprocating piston air compressor according to claim 1, wherein the number of exhaust valves in the first cylinder head is greater than the number of exhaust valves in the second cylinder head.

25. The reciprocating air compressor according to claim 1, wherein the number of exhaust valves in the first cylinder head is less than the number of exhaust valves in the second cylinder head.

26. The reciprocating piston air compressor according to claim 1, wherein the compression ratio is about 2.5 to 1 to about 5.1 to 1.

27. The reciprocating piston air compressor according to claim 26, wherein the compression ratio is about 3.3 to 1 to about 4.3 to 1.

28. The reciprocating piston air compressor according to claim 1, wherein at least one of the intake or exhaust valves in at least one of the first cylinder head and the second cylinder head is a reed valve.

29. The reciprocating piston air compressor according to claim 1, wherein at least one of the intake or exhaust valves in at least one of the first cylinder head and the second cylinder head is a channel valve.

30. The reciprocating piston air compressor according to claim 1, wherein at least one of the intake or exhaust valves in at least one of the first cylinder head and the second cylinder head is a disc valve.

31. The reciprocating piston air compressor according to claim 1, wherein at least one of the intake or exhaust valves in at least one of the first cylinder head and the second cylinder has a spring and wherein the compression to force ratio of the spring is about 0.04921 inch of compression per pound of force applied to about 0.08202 inch of compression per pound of force applied.

32. The reciprocating piston air compressor according to claim 1, wherein the total number of intake valves and exhaust valves in the first cylinder head is between 4 and 8.

33. The reciprocating piston air compressor according to claim 1, wherein the total number of intake valves and exhaust valves in the second cylinder head is between 4 and 8.

34. The reciprocating piston air compressor according to claim 1, wherein the area of the first end of the first piston is between about 3 square inches and about 14.0 square inches.

35. The reciprocating piston air compressor according to claim 1, wherein at least one of the intake valves or at least one of the exhaust valves in the first cylinder head has a valve element having a surface facing the first cylinder bore, and wherein the area of the surface of the valve element facing the first cylinder bore is between about 1 square inches and about 17.5 square inches.

36. The reciprocating piston air compressor according to claim 1, wherein at least one of the intake valves or at least one of the exhaust valves in the second cylinder head has a valve element having a surface facing the second cylinder bore, and wherein the area of the surface of the valve element facing the second cylinder bore is between about 1 square inches and about 17.5 square inches.

37. The reciprocating piston air compressor according to claim 1, further including a gasket located between either the surface of the first cylinder assembly and the first cylinder head or the surface of the second cylinder assembly and the second cylinder head and wherein the thickness of the gasket is between about 0.0220 inch and about 0.0378 inch.

38. The reciprocating piston air compressor according to claim 37, wherein the thickness of the gasket is between about 0.0275 inch and about 0.0315 inch.

39. The reciprocating piston air compressor according to claim 1, wherein the volume between the surface of the first cylinder assembly and the first cylinder head is between about 0.2 cubic inches and about 0.4 cubic inches.

40. The reciprocating piston air compressor according to claim 39, wherein the volume between surface of the first cylinder assembly and the first gasket head is about 0.33 cubic inches.

41. The reciprocating piston air compressor according to claim 1, wherein the volume between surface of the second cylinder assembly and the second cylinder head is between about 0.2 cubic inches and about 0.4 cubic inches.

42. The reciprocating piston air compressor according to claim 41, wherein the volume between surface of the second cylinder assembly and the second cylinder head is about 0.33 cubic inches.

43. A reciprocating piston air compressor, having: a first cylinder assembly having a first cylinder head, a first cylinder bore having a volume, a first piston disposed in the first cylinder bore, the first cylinder bore having a first end facing the first cylinder head, the first end of the first cylinder bore having a circumference defining an area; at least first and second intake valves and at least first and second exhaust valves in the first cylinder head, the first and second intake valves and the first and second exhaust valves in the first cylinder head positioned above the first end of the first cylinder bore and within the circumference of the first end of the first cylinder bore; a second cylinder assembly having a second cylinder head, a second cylinder bore having a volume, a second piston disposed in the second cylinder bore, the second cylinder bore having a first end facing the second cylinder head, the first end of the second cylinder bore having a circumference defining an area; and at least first and second intake valves and at least first and second exhaust valves in the second cylinder head, the first and second intake valves and the first and second exhaust valves in the second cylinder head positioned above the first end of the second cylinder bore partially within the circumference of the first end of the second cylinder bore and partially outside the circumference of the first end of the second cylinder bore.

44. The reciprocating piston air compressor according to claim 43, wherein the volume of the second cylinder bore is less than the volume of the first cylinder bore.

45. The reciprocating piston air compressor according to claim 43, wherein between about 0.1% and about 5.0% of the surface area of the first and second intake valves and the first and second exhaust valves facing the first end of the second cylinder bore are positioned inside the circumference of the first end of the second cylinder bore.

46. A reciprocating piston air compressor, having: a first cylinder assembly having a first cylinder head, a first cylinder bore having a volume, a first piston disposed in the first cylinder bore, the first piston having a first end facing the first cylinder head, the first end of the first piston having a circumference defining an area; at least first and second intake valves and at least first and second exhaust valves in the first cylinder head, the first and second intake valves and the first and second exhaust valves in the first cylinder head positioned above the first end of the first cylinder bore and within the circumference of the first end of the first piston; a second cylinder assembly having a second cylinder head, a second cylinder bore having a volume, a second piston disposed in the second cylinder bore, the second piston having a first end facing the second cylinder head, the first end of the second piston having a circumference defining an area; and at least first and second intake valves and at least first and second exhaust valves in the second cylinder head, the first and second intake valves and the first and second exhaust valves in the second cylinder head positioned above the first end of the second cylinder bore partially within the circumference of the first end of the second piston and partially outside the circumference of the first end of the second piston.

47. The reciprocating piston air compressor according to claim 46, wherein the volume of the second cylinder bore is less than the volume of the first cylinder bore.

48. The reciprocating piston air compressor according to claim 46, wherein between about 0.1% and about 5.0% of the surface area of the first and second intake valves and the first and second exhaust valves facing the first end of the second cylinder bore are positioned inside the circumference of the first end of the second piston.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 is a perspective view of an air compressor according to one embodiment of the present invention.

[0030] FIG. 2 is a perspective view of a first cylinder assembly that is a component of the air compressor shown in FIG. 1.

[0031] FIG. 3 is a perspective view of the first cylinder assembly shown in FIG. 2 with the cylinder head removed.

[0032] FIG. 4 is a perspective, cross-sectional view taken along line 4-4 in FIG. 2.

[0033] FIG. 5 is a perspective view of a second cylinder assembly that is a component of the air compressor shown in FIG. 1.

[0034] FIG. 6 is a perspective view of the second cylinder assembly shown in FIG. 2 with the cylinder head removed.

[0035] FIG. 7 is a perspective, cross-sectional view taken along line 7-7 in FIG. 5.

[0036] FIG. 8 is a perspective view of certain elements of valves that are components of the air compressor shown in FIG. 1.

[0037] FIG. 9 is a perspective, cross-sectional view taken along line 9-9 in FIG. 8.

[0038] FIG. 10 is a perspective view of a valve member that is one of the valve elements shown in FIG. 8.

[0039] FIG. 11 is a schematic view showing certain relationships between components of the air compressor shown in FIG. 1 according to certain embodiments of the present invention.

[0040] FIG. 12 is a schematic view showing certain relationships between components of the air compressor shown in FIG. 1 according to certain embodiments of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0041] FIG. 1 is a perspective view of an air compressor 10 according to one embodiment of the present invention. Air compressor 10 generally includes a first cylinder assembly 20, a second cylinder assembly 30, a motor 40, and a tank 50

[0042] Referring to FIGS. 2-4, in the embodiment shown, first cylinder assembly 20 includes a cylinder body 21 and a cylinder head 22. Cylinder body 21 includes a cylinder bore 23 surrounded by a surface 24. Surface 24 is surrounded by a gasket seat 24A. Cylinder bore 23 includes a first end 23A having a circumference 23B defining an area 23C. First end 23A of bore 23 faces cylinder head 22. A piston 25 is disposed within cylinder bore 23. Piston 25 includes a first end 25A having a circumference 25B defining an area 25C. First end 25A of piston 25 faces cylinder head 22. Cylinder head 22 includes an inlet 22A and an outlet 22B. A gasket 25 is positioned on gasket seat 24A. During operation or air compressor 10, air is drawn into and exhausted from the volume between cylinder head 22 and surface 24 via inlet 22A and outlet 22B as described below.

[0043] Referring to FIGS. 5-7, in the embodiment shown, second cylinder assembly 30 includes a cylinder body 31 and a cylinder head 32. Cylinder body 31 includes a cylinder bore 33 surrounded by a surface 34. Surface 34 is surrounded by a gasket seat 34A. Bore 33 includes a first end 33A having a circumference 33B defining an area 33C. First end 33A of bore 33 faces cylinder head 32. A piston 35 is disposed within cylinder bore 33. Piston 35 includes a first end 23A having a circumference 35B defining an area 35C. First end 35A of piston 35 faces cylinder head 32. Cylinder head 32 includes an inlet 32A and an outlet 32B. A gasket 35 is positioned on gasket seat 34A. During operation or air compressor 10, air is drawn into and exhausted from the volume between cylinder head 32 and surface 34 via inlet 32A and outlet 32B as described below.

[0044] Referring to FIGS. 2-7, in the embodiment shown, each of first cylinder head 22 and second cylinder head 32 includes a plurality of intake valves 60. Depending on the orientation of valves 60 within first cylinder head 22 and second cylinder head 32, valves 60 function as either intake valves or exhaust valves. Specifically, valves 60 functioning as intake valves are oriented 180 degrees from the valves 60 functioning as exhaust valves.

[0045] Referring to FIG. 4, and 7-10, each valve 60 includes a valve body 61 having a sealing surface 62, a valve member 63, a spring 64, and a retainer 65. Valve members 63 in the embodiment shown are generally disc shaped members having opposed surfaces 63A and 63B each of which has a circumference 63C defining an area 63D. Surfaces 63A face the first end of the cylinder bore and piston in either first cylinder assembly 20 or second cylinder assembly 30, respectively, when valves 60 are installed to function as intake valves. Surfaces 63B face the first end of the cylinder bore and piston in either first cylinder assembly 20 or second cylinder assembly 30, respectively, when valves 60 are installed to function as exhaust valves. In certain embodiments of the invention, area 63D is between about 1 in.sup.2 and about and about 17.5 in.sup.2. Spring 64 is captured between surface 63A of valve member 63 and retainer 65 and urges valve member 63 against sealing surface 62 of valve body 61.

[0046] In use, motor 40 is operated to reciprocate pistons 25 and 35 within cylinder bores 23 and 33, respectively. The downstroke of pistons 25 and 35 draws air through inlets 22A and 32A of cylinder heads 22 and 32, through valves 60 that are oriented to act as inlet valves, and into first cylinder bore 23 and second cylinder bore 33, respectively. The upstroke of pistons 25 and 35 exhausts compressed air from first cylinder assembly 20 and second cylinder assembly 30, respectively, through valves 60 that are oriented to act as exhaust valves, and through outlets 22B and 32B of cylinder heads 22 and 32, respectively. Specifically, air drawn through valves 60 (whether they are oriented to act as intake valves or exhaust valves) will apply pressure against whichever of surfaces 63A and 63B are facing cylinder bores 23 and 33. When the pressure of the air on surface 63A or 63B of a particular valve member 63 is sufficient to overcome the force of spring 64, valve member 63 moves away from sealing surface 62, thereby permitting air to pass through valve 60 through. In the embodiment shown, air compressor 10 is a two-stage air compressor. First cylinder assembly 20 intakes air, compresses it, and exhausts the compressed air to inlet 33B of second cylinder assembly 30, which further compresses the air to a higher pressure than does firs cylinder assembly 20 and exhausts it to tank 50. In this embodiments of the invention, the volume of cylinder bore 23 of first cylinder assembly 20 is greater than the volume of cylinder bore 33 of second cylinder assembly 30.

In Other Embodiments of the Invention

[0047] 1. Both circumference 23B and area 23C of cylinder bore 23 and circumference 25B and area 25C of piston 25 of first cylinder assembly 20 are larger than circumference 33B and area 33C of cylinder bore 33 and circumference 35B and area 35C of piston 35 of second cylinder assembly 30; and/or [0048] 2. The total area of surfaces 63A and 63B of valve members 63 that face cylinder bore 23 and piston 25 of first cylinder assembly 20 is less than area 23C and/or area 25C, and the total area of surfaces 63A and 63B of valve members 63 that face cylinder bore 33 and piston 35 of second cylinder assembly 30 is greater than area 33C and/or area 35C. For example, in one embodiment, the total area of surfaces 63A and 63B of valve members 63 that face cylinder bore 23 and piston 25 in first cylinder assembly 20 is about 25% to about 80% of area 23C and/or area 25C (and, in certain embodiments preferably about 73%), and the total area of surfaces 63A and 63B of valve members 63 that face cylinder bore 33 and piston 35 in second cylinder assembly 30 is about 25% to about 180% of area 33C and/or area 35C (and, in certain embodiments, preferably about 265%); and/or [0049] 3. Area 25C of piston 25 and/or area 35C of piston 35 is between about 3.0 in.sup.2 and 14.0 in.sup.2; and/or [0050] 4. The area occupied by surfaces 63A and 63B of valve members 63 that face cylinder bore 23 and piston 25 of first cylinder assembly 20 fits entirely within area 23C of cylinder bore 23 and/or area 25C of piston 25, and the area occupied by surfaces 63A and 63B of valve members 63 that face cylinder bore 33 and piston 35 of second cylinder assembly 30 does not fit entirely within area 33C of cylinder bore 33 or area 35C of piston 35 (FIGS. 11 and 12), and/or between about 0.1% and about 5.0% of the area occupied by surfaces 63A and 63B of valve members 63 that face cylinder bore 33 and piston 35 of second cylinder assembly 30 is within area 33C of cylinder bore 33 or area 35C of piston 35, and in some embodiments preferably between about 1.0% and about 2.5%, and/or in certain embodiments about 1.57%; and/or [0051] 5. Air compressor 10 has a compression ratio between about 2.5 to 1 to about 5.1 to 1, and, in certain embodiments, preferably between about 3.3 to 1 and about 4.3 to 1, and in certain embodiments 3.8 to 1.

[0052] Utilizing multiple valves in accordance with the present invention (as opposed to a single larger intake valve and a single larger exhaust valve per cylinder assembly) has several advantages over certain prior art air compressors that use a single larger intake valve and a single larger exhaust valve. First, a larger valve requires a greater force to seal properly (i.e., a stronger spring requiring greater lift force). As a result, the air must be pressurized to a greater degree in order to unseat the valve member from the sealing surface of the valve body of the larger valve as compared to the level of pressurization required to unseat the valve members from the sealing surfaces of each of the smaller valves. Second, the lower lift force required to unseat the valve members of the smaller valves permits an increase in the intake capacity of the system by increasing the net surface area of the valve members beyond that which can be achieved with a single larger valve due the increasing difficulty in unseating the valve member as the size of the valve member increases. Third, multiple smaller valves create less back pressure when exhausting the compressed air from the cylinder assemblies. Fourth, the more a spring is compressed the more resistance it provides to further compression. Using multiple smaller valves (which, as stated above, provides greater net surface area for air intake) means that the valves do not have to open as far (thereby requiring less spring compression) to let in the same amount of air as compared with a single larger valve. In certain embodiments of the invention, spring 64 has a compression to force ratio of between about 0.04921 inch of spring compression per pound of force applied to about 0.08202 inch of spring compression per pound of force applied.

[0053] Limiting the volume between cylinder head 22 and surface 24 of first cylinder assembly 20 and the volume between cylinder head 32 and surface 34 of second cylinder assembly 30 also improves operation of air compressor 10. This is because a smaller volume between the cylinder heads and the surfaces reduces the dead air space, thereby increasing the effectiveness of the system in compressing and moving air (i.e., the system is able to move a greater volume of air relative to the energy expended). The smaller volume also results in lower back pressure and less energy consumption when operating the air compressor. In certain embodiments of the invention, the volume is limited by limiting the thickness of gasket seats 24A and 34A and the thickness of gaskets 25 and 35. In certain embodiments of the invention, the thickness of gaskets 25 and/or 35 is between about 0.0220 inch and about 0.0378 inch, and, in certain embodiments, preferably between about 0.0275 inch and about 0.0315 inch. In some embodiments, the volume between cylinder head 22 and surface 24 of first cylinder assembly 20 and/or the volume between cylinder head 32 and surface 34 of second cylinder assembly 30 is between about 0.2 cubic inches and about 0.4 cubic inches, and, in certain embodiments, between about 0.2893 cubic inches and about 0.3314 cubic inches.

[0054] The present invention provides a number of advantages over certain prior art air compressors. For example, air compressors according to the present invention utilize 20%-25% less energy, produce higher cubic feet per minute displacement, and result in lower operating temperatures (at least as low as 180 F. in certain embodiments) than certain prior art air compressors.

[0055] Although the present invention has been shown and described in detail the same is for purposes of illustration only. Numerous modifications can be made to the embodiments described without departing from the scope of the present invention. For example, a cylinder assembly can have the same number of intake valves and exhaust valves or a different number of intake valves and exhaust valves. The number of intake valves per cylinder assembly can be greater than or less than the number of exhaust valves per cylinder assembly. The total number of valves in one cylinder assembly can be the same as, greater than, or less than the total number of valves in another cylinder assembly. The number of intake valves and/or exhaust valves in one cylinder assembly can be the same as, greater than, or less than the number of intake valves and/or exhaust valves in another cylinder assembly. Valve types other than disc valves, such as reed valves or channel valves can be utilized.