U.S. patent application number 15/868355 was filed with the patent office on 2018-07-12 for fluid compressor.
This patent application is currently assigned to Bristol Compressors International, LLC. The applicant listed for this patent is Bristol Compressors International, LLC. Invention is credited to Joseph Hill, Tri Minh Huynh, Terry Lyons, John Williams, Michael Young.
Application Number | 20180195503 15/868355 |
Document ID | / |
Family ID | 62782838 |
Filed Date | 2018-07-12 |
United States Patent
Application |
20180195503 |
Kind Code |
A1 |
Lyons; Terry ; et
al. |
July 12, 2018 |
FLUID COMPRESSOR
Abstract
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.
Inventors: |
Lyons; Terry; (Bluff City,
TN) ; Hill; Joseph; (Pinckney, MI) ; Huynh;
Tri Minh; (Loganville, GA) ; Williams; John;
(Brasstown, NC) ; Young; Michael; (Wichita,
KS) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bristol Compressors International, LLC |
Bristol |
VA |
US |
|
|
Assignee: |
Bristol Compressors International,
LLC
Bristol
VA
|
Family ID: |
62782838 |
Appl. No.: |
15/868355 |
Filed: |
January 11, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62445218 |
Jan 11, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04B 27/0409 20130101;
F04B 39/0284 20130101; F04B 39/123 20130101; F04B 39/06 20130101;
F04B 39/0027 20130101; F04B 39/0276 20130101; F04B 35/04
20130101 |
International
Class: |
F04B 39/12 20060101
F04B039/12; F04B 27/04 20060101 F04B027/04; F04B 39/06 20060101
F04B039/06; F04B 35/04 20060101 F04B035/04; F04B 39/02 20060101
F04B039/02; F04B 39/00 20060101 F04B039/00 |
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.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.
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 INVENTION
[0002] This application relates to various improvements in
structures for fluid compressors.
[0003] Refrigerant compressors are utilized to compress a
refrigerant for use in a refrigerant cycle.
[0004] 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.
[0005] 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.
[0006] The present invention seeks to address these
deficiencies.
SUMMARY OF THE INVENTION
[0007] In 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.
[0008] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic view of a compressor in accordance
with one embodiment of the present invention;
[0010] FIG. 2 is a side and cross-sectional view of the shaft and
piston assembly shown in FIG. 1;
[0011] FIG. 3 is a top view of an embodiment with 4 pistons that
simultaneously proceed through their compression cycles;
[0012] FIG. 4 is an embodiment of a piston assembly for a 4 piston
fluid compressor that does not simultaneously compress;
[0013] FIG. 5 is a cross-section through an assembly of a
horizontal embodiment of the present invention;
[0014] FIG. 6 is a cross-section through a compression chamber of
an alternative embodiment of the present invention; and
[0015] FIG. 7 is a close up cross-sectional view of the connection
between the stator laminates and the housing of one embodiment of
the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] A fluid compressor 20 is illustrated in FIG. 1 having a
suction tube 22 providing a suction refrigerant into a suction
chamber 24. A motor 26 is mounted within a housing, and drives a
rotary shaft 28. Rotary shaft 28 causes a piston assembly 30 to
reciprocate a pair of attached pistons 35 through the connection of
yoke 29 and an eccentric pin 31. Thus, the pistons 35 are directly
connected to piston assembly 30. Conventional compressors may
attach the pistons to connecting rods which requires more labor and
maintenance. The present invention eliminates these problems.
[0017] 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.
[0018] 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, FIG. 6 shows a compression
chamber with an inlet valve 33 on a lower side surface of the
compression chamber. When the piston 35 retreats for a suction
stroke, the valve 33 is exposed to the compression chamber. This
again allows a maximizing of the distance between the intake and
discharge valves, maximizing the discharge volumetric geometry.
[0019] 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.
[0020] 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.
[0021] FIG. 2 also shows high pressure relief valve 85. This valve
is designed to vent the high pressure from the discharge side if
that pressure exceeds a critical value. This prevents catastrophic
failure of the compressor housing. FIG. 2 also shows seal point 90,
onto which an o-ring (not shown) is mounted. This seal prevents
high pressure compressed fluid from leaking back into the intake
side.
[0022] 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.
[0023] 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.
[0024] As shown in FIG. 1, motor 26 is in direct contact with the
inner surface of housing 21. This allows heat generated by motor 26
to more efficiently escape the compressor 20. For example, FIG. 7
shows a close up of the contact between the motor laminate layers
52 and the housing 21. (Although the housing has a circular
cross-section, the housing is shown in this view as having straight
sides due to the small scale.) Each stator laminate layer 52 has a
thickness of approximately 0.020 in. Each stator laminate layer 52
may then line up with a corresponding heat dissipation fin 23 on an
outer surface of housing 21 to promote heat transfer from the
laminate layer 52, through housing 21, and out corresponding fin
23. Fin 23 is shown with a triangular cross-section, but any shape
or configuration suitable for heat dissipation is possible. These
modifications are within the scope of the invention as claimed.
[0025] 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. FIG. 5 shows a horizontal
configuration of the present invention. The only changes needed to
place the compressor horizontally is the feet need to be moved to
support the compressor. Also, the compressor 20 is not completely
horizontal, but at approximately 5-10 degrees from horizontal to
ensure oil 60 can continue to be drawn into the bottom of lower
bearing 70.
[0026] Further, as shown in FIG. 1, the outer housing is
cylindrical. In contrast, conventional compressor housings have an
oval horizontal cross-section. The cylindrical outer housing of the
present invention has several advantages. First, the circular
cross-section is stronger, and thus higher pressure operation is
possible, allowing higher compression ratios and higher
performance. Further, the cylindrical shape creates a smaller oil
sump volume 60 that must be filled with oil. Reducing the amount of
oil needed saves costs throughout the lifetime of the compressor.
Additionally, oval cross-sections may vibrate during operation of
the compressor. This creates added noise that is not generated by
the circular cross-section.
[0027] FIG. 3 shows an alternative embodiment which include 4
pistons 135, each of which proceed through the compression cycle
simultaneously. Springs 137 are located in the compression chambers
at an outer end to push the pistons 135 back when cam 139 moves to
remove the force on piston 135. Cam 139 rotates on shaft 128, which
is turned by a motor as in the first embodiment. Thus, the forces
on the pistons that could cause vibrations in fact cancel out to
eliminate bearing load and perfectly balance the mechanism. This
reduces noise, vibration, and power usage. Further, either or both
of the modifications may be used within the scope of the invention
as claimed. That is, 2 piston unsynchronized, 4 piston
unsynchronized, 2 piston synchronized, and 4 piston synchronized
are all within the scope of the invention as claimed.
[0028] In this regard, FIG. 5 shows a piston assembly for a 4
piston unsynchronized configuration. This piston assembly includes
a connection portion 30A that extends above the piston surfaces to
allow for a perpendicular piston assembly to reciprocate below the
portion 30A as the shaft rotates. Thus, 4 pistons can run in an
unsynchronized manner to compress fluid.
[0029] 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.
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