FLUID COMPRESSOR
A fluid compressor includes a housing; a compression chamber within the housing; a motor; a shaft that is rotated by the motor; and a piston assembly including at least two pistons directly connected to each other without any connecting rods. The piston assembly performs a reciprocating motion when acted on by the shaft such that the at least two pistons move within the compression chamber to compress a fluid.
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This application claims priority under 35 U.S.C. § 119(e) to U.S. Application No. 62/445,218, filed Jan. 11, 2017. This application is incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTIONThis application relates to various improvements in structures for fluid compressors.
Refrigerant compressors are utilized to compress a refrigerant for use in a refrigerant cycle.
In two known types of refrigerant compressors, significant drawbacks exist that reduce performance and increase cost. First, in conventional reciprocating compressors, a pair of pistons are driven to reciprocate within compression chambers by a motor. Fluid enters through an entry passage in each compression chamber and exits through a discharge passage. These passages are generally in a same surface of the compression chamber, in a surface opposite the face of the piston. This close proximity between the entry and discharge passages allows heat from the discharge passage to travel to the suction entry passage, heating up the fluid entering the chamber. This causes the fluid to expand, which reduces the amount of fluid entering the chamber for each stroke of the piston. Thus, the capacity of the compressor is reduced, and performance is reduced.
Second, in conventional scroll compressors, there are many places throughout the travel path of the fluid that can leak, especially at higher pressures. Accordingly, scroll compressors cannot provide high pressure operation or compression ratios. For example, compression ratios of over 7:1 are very problematic for scroll compressors, likely leading to leaks as well as higher friction levels within the compression passages and reduced performance.
The present invention seeks to address these deficiencies.
SUMMARY OF THE INVENTIONIn one embodiment of the present invention, a fluid compressor includes a housing; a compression chamber within the housing; a motor; a shaft that is rotated by the motor; and a piston assembly including at least two pistons directly connected to each other without any piston rods. The piston assembly performs a reciprocating motion when acted on by the shaft such that the at least two pistons move within the compression chamber to compress a fluid.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
A fluid compressor 20 is illustrated in
Suction plenums 32 lead the refrigerant from suction chamber 24 through inlet valves 33 and into compression chambers 36, defined by a crankcase or housing 34. Discharge valve assemblies 38 are placed at an opposite end of each compression chamber 36 from the inlet valves 33. The refrigerant passes outwardly through the discharge valves 38 into a discharge chamber 40, and then through a discharge tube 42. This dramatic separation of the suction discharge gas flow from the intake gas flow results in less heat pickup in the intake suction stream. This results in more dense gas into compression chamber, which allows compressor 20 to provide more capacity out of a smaller mechanism.
Further, the separation of the discharge valve 38 from the inlet valve 33 maximizes the discharge volumetric geometry, allowing reduced pressure drops and improved fluid flow. This can be accomplished whether the gas is brought in through a valve on a face of the piston or through a valve in the bore (a side of the compression chamber) that is exposed when the piston retreats during the suction stroke. For example,
By maximizing the discharge volumetric geometry, the size of the discharge valve can be made significantly larger. A larger discharge valve doesn't need to open as much to allow the compressed fluid out of the compression chamber. This improves valve timing and reduces backflow into compression chamber, further improving performance.
The disclosed configuration also eliminates the need for any discharge mufflers, internal high pressure exhaust tubes, mechanical mounting springs or mounts, cylinder heads, and valve plates. The elimination of all of these parts also reduces manufacturing costs and maintenance. In particular, the volume in housing 34 of the discharge chamber of compressor 20 becomes a discharge muffler chamber. This eliminates the need for a separate part for a discharge muffler.
In comparison to a scroll compressor, the present invention includes far fewer possible leakage paths. Thus, the present invention can perform at much higher compression ratios than a scroll compressor, such as greater than a 10:1 compression ratio. Thus allows for usage in such applications as medium and low temperature refrigeration, high ambient temperature air conditioning, and more severe heat pump conditions.
Compressor 20 also includes lower bearing 70 and upper bearing 80. These bearings allow for a smaller sized motor, which results in greater efficiently and lower cost.
As shown in
Moreover, this direct connection to the outer housing means that the compressor can be deployed in varying configurations, such as standing up or on its side.
Further, as shown in
In this regard,
A worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
Claims
1. A fluid compressor comprising:
- a housing;
- a compression chamber within the housing;
- a motor;
- a shaft that is rotated by the motor; and
- a piston assembly including at least two pistons directly connected to each other without any connecting rods, the piston assembly performing a reciprocating motion when acted on by the shaft such that the at least two pistons move within the compression chamber to compress a fluid.
2. The fluid compressor as set forth in claim 1, wherein the piston assembly includes 2 pistons.
3. The fluid compressor as set forth in claim 1, wherein the piston assembly includes 4 pistons.
4. The fluid compressor as set forth in claim 3, wherein each of the 4 pistons moves through a compression cycle simultaneously.
5. The fluid compressor as set forth in claim 1, wherein the motor is fixed directly to an inner surface of the outer housing.
6. The fluid compressor as set forth in claim 1, wherein fluid enters the compression chamber through a first surface of the compression chamber and exits the compression chamber through a second surface of the compression chamber that is an opposite surface from the first surface.
7. The fluid compressor as set forth in claim 6, wherein the first surface is a surface of the at least one piston.
8. The fluid compressor as set forth in claim 1, wherein fluid enters the compression chamber through a first surface of the compression chamber and exits the compression chamber through a second surface of the compression chamber that different from the first surface.
9. The fluid compressor as set forth in claim 8, wherein the first surface is a bottom surface of the compression chamber.
10. The fluid compressor as set forth in claim 1, further comprising:
- a plurality of heat dissipation fins on an outer surface of the housing.
11. The fluid compressor as set forth in claim 10, wherein each of the plurality of heat dissipation fins corresponds to a layer of stator laminate of the motor within the housing.
12. The fluid compressor as set forth in claim 1, wherein a discharge volume muffles noise created within the compressor.
13. The fluid compressor as set forth in claim 1, further comprising:
- an oil sump within a lower bearing that supports the shaft.
14. The fluid compressor as set forth in claim 13, wherein the oil sump has a slanted surface having an angle of approximately 25-35 degrees with a horizontal.
Type: Application
Filed: Jan 11, 2018
Publication Date: Jul 12, 2018
Applicant: Bristol Compressors International, LLC (Bristol, VA)
Inventors: Terry Lyons (Bluff City, TN), Joseph Hill (Pinckney, MI), Tri Minh Huynh (Loganville, GA), John Williams (Brasstown, NC), Michael Young (Wichita, KS)
Application Number: 15/868,355