U.S. patent application number 09/766967 was filed with the patent office on 2002-07-25 for suction accumulator for air conditioning systems.
Invention is credited to Corrigan, Daniel Leonard, Cram, Kenneth Peter Luke.
Application Number | 20020095948 09/766967 |
Document ID | / |
Family ID | 25078077 |
Filed Date | 2002-07-25 |
United States Patent
Application |
20020095948 |
Kind Code |
A1 |
Corrigan, Daniel Leonard ;
et al. |
July 25, 2002 |
SUCTION ACCUMULATOR FOR AIR CONDITIONING SYSTEMS
Abstract
A deflector for use in an accumulator that provides a reservoir
for the liquid-phase of a heat transfer medium circulating in a
closed-loop air conditioning system is configured to prevent liquid
phase medium from the supply pipe from entering the inlet area of
the delivery pipe of the accumulator. The deflector has a recessed
underside defined by a depending peripheral skirt having an outline
that is closely spaced with respect to the peripheral wall of the
accumulator to define therewith an annular gap. The upper wall of
the deflector is positioned to be impinged by medium delivered from
the supply pipe and is configured to distribute radially and impart
rotation to the medium, thus enhancing the separation of the liquid
phase along the accumulator peripheral wall, especially as the
liquid and gaseous phase pass through the annular gap. The open
inlet area of the delivery pipe is shielded within the recessed
underside of the deflector.
Inventors: |
Corrigan, Daniel Leonard;
(Kingston, CA) ; Cram, Kenneth Peter Luke;
(Belleville, CA) |
Correspondence
Address: |
BAKER & DANIELS
Suit 2700
300 North Meridian Street
Indianapolis
IN
46204
US
|
Family ID: |
25078077 |
Appl. No.: |
09/766967 |
Filed: |
January 22, 2001 |
Current U.S.
Class: |
62/503 ;
62/474 |
Current CPC
Class: |
F25B 2400/03 20130101;
F25B 43/006 20130101; F25B 2400/02 20130101; F25B 43/003 20130101;
B01D 45/16 20130101 |
Class at
Publication: |
62/503 ;
62/474 |
International
Class: |
F25B 043/00 |
Claims
1. An accumulator providing a reservoir for liquid-phase of a heat
transfer medium that circulates in a closed-loop air conditioning
system, said accumulator comprising: a hollow container defined by
a peripheral wall and closed upper and lower ends; a supply pipe
for delivering the medium from an evaporator in mixed
liquid/gaseous phase into an upper region of said container; a
delivery pipe in said container for passing medium predominantly in
gaseous phase, from said container to a compressor in said system,
said delivery pipe having an open inlet area located in said upper
region of said container; and a deflector positioned in said upper
region, said deflector being configured to prevent liquid phase
medium from said supply pipe from entering the inlet area of the
delivery pipe; said deflector having a recessed underside defined
by a depending peripheral skirt having an outline that is closely
spaced with respect to said peripheral wall to define therewith an
annular gap; said deflector skirt adjoining the periphery of an
upper wall of the deflector, said upper wall being positioned to be
impinged by medium delivered from said supply pipe and being
configured to distribute radially and impart rotation to said
medium, thus enhancing the separation of the liquid phase along the
accumulator peripheral wall especially as the liquid and gaseous
phase pass through the annular gap, the open inlet area of the
delivery pipe being shielded within the recessed underside of the
deflector.
2. An accumulator as claimed in claim 1 wherein said deflector
upper wall has on its upper surface a plurality of channels
extending from a central part towards the periphery thereof.
3. A deflector as claimed in claim 1 wherein said upper wall of the
deflector has on its upper side a plurality of projecting ribs each
extending from a central area to the periphery thereof.
4. An accumulator as claimed in claim 1 wherein both said supply
pipe and said delivery pipe pass through sealed openings in the
upper end of the container, said delivery pipes being of generally
U-shape having a curved bight that lies within the lower end of the
container, said delivery pipe extending through a sealed opening in
a lateral region of the upper wall of the deflector.
5. An accumulator as claimed in claim 1 wherein said upper wall of
the deflector is configured with a series of V-shaped grooves which
expand in size continuously towards the periphery.
6. An accumulator as claimed in claim 1 wherein said peripheral
wall of the deflector includes projecting ribs that are adapted to
engage the peripheral wall of the container to maintain said
annular gap and to support the deflector in rattle-free condition
with respect to said container.
7. An accumulator as claimed in claim 6 wherein said deflector is
fabricated as a plastic moulding.
8. An accumulator as claimed in claim 1 wherein said upper wall of
the deflector is domed, being higher in its central area than at
its periphery, and wherein the configuration to channel liquid
phase medium comprises a series of radially outwardly and
downwardly extending V-shaped grooves on the upper surface
thereof.
9. An accumulator as claimed in claim 7 wherein said grooves extend
in a somewhat spiral arrangement towards the periphery to provide a
swirl to liquid medium passing therealong.
10. An accumulator as claimed in claim 1 wherein the recessed
underside of the deflector has a pluarality of channels, ribs or
grooves extending from a central part towards the periphery
thereof, better to swirl and direct the gaseous refrigerant into
the open inlet area of the delivery pipe.
Description
BACKGROUND OF THE INVENTION
[0001] (a) Field of the Invention
[0002] This invention relates to a new or improved suction
accumulator for use in air-conditioning systems including
refrigeration systems and heating systems that include a heat
pump.
[0003] (b) Description of the Prior Art
[0004] Closed-loop refrigeration systems conventionally employ a
compressor that draws in gaseous refrigerant at relatively low
pressure and discharges hot refrigerant at relatively high
pressure. The hot refrigerant condenses into liquid as it is cooled
in a condenser. A small orifice or valve divides the system into
high-pressure and low-pressure sides. The liquid on the
high-pressure side passes through the orifice or valve and turns
into a gas in the evaporator as it picks up heat. At low heat loads
it is not desirable or possible to evaporate all the liquid.
However, liquid refrigerant entering the compressor (known as
"slugging" or "carryover") causes system efficiency loss and can
cause damage to the compressor. Hence it is standard practice to
include an accumulator between the evaporator and the compressor to
separate and store the excess liquid.
[0005] An accumulator is typically a metal can, welded together,
and often has fittings attached for a switch and/or charge port.
One or more inlet tubes and an outlet tube pierce the top, sides,
or occasionally the bottom, or attach to fittings provided for that
purpose. The refrigerant flowing into a typical accumulator will
impinge upon a deflector or baffle intended to reduce the
likelihood of liquid flowing out the exit. There are many kinds of
baffles and deflectors in the prior art, all designed to reduce
liquid carryover (see for instance U.S. Pat. Nos. 5,787,729,
5,471,854, 5,201,792, 5,184,479, 5,021,792, 4,768,355, 4,651,540,
4,270,934, and 4,229,949), and the prior art includes designs that
claim not to need deflectors (U.S. Pat. Nos. 5,1798,44, 5,471,854).
However in current standard use most accumulators use a variation
of the dome (U.S. Pat. No. 4,474,035) or "Dixie cup" (U.S. Pat. No.
4,111,005) deflector--usually because they are simple and
cost-effective. The above mentioned patents are incorporated herein
by reference, in their entirety. There remains a need for a
deflector design that directs the flow of refrigerant in the best
possible manner to separate the gas from the liquid and minimize
liquid carryover.
SUMMARY OF THE INVENTION
[0006] The invention provides an accumulator providing a reservoir
for liquid-phase of a heat transfer medium that circulates in a
closed-loop air conditioning system, said accumulator comprising: a
hollow container defined by a peripheral wall and closed upper and
lower ends; a supply pipe for delivering the medium from an
evaporator in mixed liquid/gaseous phase into an upper region of
said container; a delivery pipe in said container for passing
medium predominantly in gaseous phase, from said container to a
compressor in said system, said delivery pipe having an open inlet
area located in said upper region of said container; and a
deflector positioned in said upper region, said deflector being
configured to prevent liquid phase medium from said supply pipe
from entering the inlet area of the delivery pipe; said deflector
having a recessed underside defined by a depending peripheral skirt
having an outline that is closely spaced with respect to said
peripheral wall to define therewith an annular gap; said deflector
skirt adjoining the periphery of an upper wall of the deflector,
said upper wall being positioned to be impinged by medium delivered
from said supply pipe and being configured to distribute radially
and impart rotation to said medium, thus enhancing the separation
of the liquid phase along the accumulator peripheral wall
especially as the liquid and gaseous phase pass through the annular
gap, the open inlet area of the delivery pipe being shielded within
the recessed underside of the deflector. The deflector of the
accumulator disclosed herein provides for rapid separation of the
liquid and gas phases of the stream of refrigerant entering the
accumulator through the supply pipe. The deflector prevents liquid
refrigerant from entering the delivery tube inlet. To this end, the
deflector preferably has an upper surface that is formed with a
series of grooves or channels extending in spiral fashion from a
central part thereof towards the periphery. The liquid and gaseous
refrigerant impinging upon this upper surface are largely deflected
outwards to the peripheral wall of the accumulator. In the prior
art, utilizing a smooth deflector surface, some portion of the
liquid phase would collect upon the wall and flow downwards through
the annular gap between the deflector and peripheral wall. However,
much of the liquid would remain entrained in (or be returned to)
the gaseous stream and be transported into the delivery pipe. In
the present invention the spiral grooves or channels on the
deflector surface impart a rotation to the refrigerant stream as it
is deflected. The higher centrifugal action of the denser liquid
phase preferentially forces it to the peripheral wall, and the
swirling of the liquid tends to keep it forced against the wall as
the liquid flows downward through the annular gap between the wall
and the deflector. The multiple spiral grooves tend to distribute
the liquid evenly and ensure that rotation and radial motion will
be imparted to all refrigerant impinging upon the deflector. The
gas will also swirl smoothly through the annular gap, and the
grooves on the underside of the deflector will tend to maintain
this swirling and aid in the re-direction of the gas into the
delivery tube inlet. The deflector thus effects superior separation
of liquid and gaseous refrigerant, reducing liquid carryover, and
smooths the gas flow, reducing deleterious suction-line pressure
drop. The result is superior refrigeration system performance.
[0007] The outlet delivery tube may be of a conventional U- or
J-shaped configuration, with one limb extending in an axial
direction through hermetically sealed joints in the top of the
accumulator and in the deflector, the other limb of the tube
opening in a sheltered position beneath the deflector and the two
limbs being joined through a curved bight portion located at the
lower end of the accumulator. The configuration of this tube will
vary depending on whether the tube is desired to exit the
accumulator through the top, bottom, or side wall. Liquid
refrigerant passing over the deflector will move under gravity to
the lower end of the accumulator which constitutes a reservoir for
the liquid. Compressor oil is contained in the liquid refrigerant,
and it must be returned to the compressor. It is gradually
entrained in known manner through a small orifice into the gas
refrigerant stream that passes out of the accumulator through the
U-tube.
[0008] The deflector may be fabricated in any suitable material
such as aluminum, rubber, plastic, or composite material. The
deflector may comprise or include material which acts as a
desiccating element. The annular gap between the peripheral skirt
of the deflector and the accumulator wall is preferably maintained
by projecting ribs on the skirt which engage the wall and support
the deflector relative thereto in rattle-free condition. It is
preferable that these ribs are shaped to aid the swirling motion of
the refrigerant flowing through the gap.
[0009] The inlet to the J-shaped delivery tube is preferably
located in guides provided on the underside of the deflector, to
maintain the position of the inlet with respect to the deflector,
especially the spacing between the underside of the deflector and
the inlet of the tube.
[0010] The deflector disclosed herein can be modified to suit any
style of accumulator, including the "top in/top out" style as
herein after illustrated and described, as well as other types of
accumulator identified as top in/side out, top in/bottom out, side
in/top out, side in/bottom out, or side in/side out. This can be
effected by changing the delivery tube and the fit of the deflector
with respect to the delivery tube to suit the particular
application.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention will further be described, by way of example
only, with reference to the accompanying drawings wherein:
[0012] FIG. 1 is a partly fragmented perspective view of a
preferred embodiment of air-conditioning accumulator in accordance
with the present invention;
[0013] FIG. 2 is a side view of the deflector and delivery tube
assembly of the accumulator drawn to a larger scale;
[0014] FIG. 3 is a perspective view of the deflector;
[0015] FIGS. 3A and 3B are enlarged fragmentary views illustrating
the portion of the deflector indicated by the circle A in FIG.
3;
[0016] FIG. 4 is a fragmentary perspective view illustrating the
underside of the deflector and delivery tube assembly of FIG. 2;
and
[0017] FIGS. 4A and 4B are fragmentary views showing the guides
connecting the delivery tube and the deflector.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] The accumulator 10 shown in FIG. 1 comprises a cylindrical
body or can 12 having a closed lower end that is closed at its
upper end by a disc-shaped top cap 16. A clutch cycling switch 18
of known design is located in the side wall 12. The top cap 16 is
penetrated by a service stem 20, an outlet port 22 for connection
to an outlet tube leading to a compressor (not shown) and an inlet
tube 24 which carries a swivel nut connector 26 for attachment to
an inlet tube or evaporator (not shown). The outlet port 22 is
adapted to be connected to a tube leading to a compressor (not
shown).
[0019] Within the upper end of the cylindrical body 12 there is
positioned a deflector 29 arranged horizontally. The body 12 also
encloses a U-shaped outlet delivery tube 30 having one limb 32
which passes through the deflector 29 and is connected to the
outlet port 22, and a second limb 34 that opens on the underside of
the deflector 29. The lower bend or bight portion 36 of the
delivery tube incorporates an oil filter 38 which surrounds a small
precision hole (not shown) in the lower end of the bight 36. This
provides an oil bleed hole located at the lowest point of the
delivery tube through which the small amount of lubricating oil
contained within the system is recirculated from the accumulator
into the refrigerant gas flow passing to the compressor. Typically
the limbs 34 or 32 of the delivery tube provide a convenient
attachment point for a container or bag or desiccant material 42,
if such is required.
[0020] The configuration of the deflector 29 is best shown in FIGS.
2, 3 and 4 as comprising an upper wall 44 surrounded by an integral
peripheral cylindrically curved skirt 46. A series of angularly
spaced integral projecting ribs 48 extend obliquely thereon and
engage snugly against the inner surface of the cylindrical body 12
thus maintaining the annular gap between this wall and the skirt 44
and retaining the deflector 29 in rattle-free condition with
respect to the wall 12. The angular orientation of the ribs tends
to enhance the swirling motion of the refrigerant as it passes
through the annular gap.
[0021] In this embodiment the upper wall 44 of the deflector has a
horizontal sector 50 formed with a bore 52 to allow the delivery
tube to pass through the deflector. The remainder of the upper wall
defines a topography of radially extending and expanding spiral
V-shaped grooves 54 which from a center point 56 run downwardly and
outwardly with a slight spiral swirl to the skirt 46.
[0022] The underside of the deflector 29 is recessed and surrounds
the upper end of the limb 34 of the outlet delivery tube, this
upper end being defined by a bell shaped fitting 58 which seats
against a series of supporting ribs 60 which are formed integrally
with the underside of the deflector 29 as shown particularly in
FIGS. 4 and 4A. The ribs 60 maintain the desired spacing of the
bell end 58 with respect to the underside of the deflector while
supporting it in rattle-free condition. The grooves on the
underside of the deflector tend to aid the swirling and direction
of the gases into the outlet delivery tube.
[0023] The accumulator 10 forms a sealed unit, there being hermetic
seals between the cap 16 and the body 12 as well as between the cap
and the fittings passing therethrough such as the service stem 20,
the conduit leading from the outlet port 22 to the compressor (not
shown) and the inlet tube 24. A snug fit is formed between the bore
52 in the deflector and the limb 32 of the delivery tube so that no
liquid refrigerant will pass through this bore.
[0024] The topography of the upper wall 44 of the deflector 29 is
such as to direct outwardly and downwardly the refrigerant that is
delivered onto this top wall from the inlet pipe 24. This
refrigerant will be a mixture of liquid and gaseous phases and it
is important to reliably guide the liquid phase to the wall and
thence to the bottom of the accumulator thus avoiding the risk that
drops of liquid can be drawn into the open bell end 58 of the
delivery tube 30. The grooves 54 achieve this effect by imparting
spin to the liquid and gaseous refrigerant as it is deflected, so
that the heavier liquid phase is forced preferentially to the wall.
The grooves 54 extend outwardly and downwardly with a slight spiral
curvature, as best seen in FIG. 3, to impart the angular movement
to the refrigerant, this being enhanced by the angled ribs 48.
Alternative arrangements to the wide V grooves 54 are shown in
FIGS. 3A and 3B. In one configuration the grooves 54 are replaced
by a series of radially and outwardly extending channels 62 as seen
in FIG. 3A. In an alternative configuration, guidance of the liquid
is effected by spirally arranged projecting ribs 64 on the top wall
44, as seen in FIG. 3B.
[0025] As an alternative to the bell end 58 of the outlet delivery
tube limb 34, it may be provided with a plain end as seen in FIG.
4B, this end being engaged by slightly modified supporting ribs
66.
[0026] The accumulator can be fabricated from any suitable material
that is convenient for the contemplated application. For automotive
air-conditioning applications it is preferable to use a strong
lightweight and non-corrosive material. For typical applications
using hydrofluorocarbon refrigerant, the preferred material is
aluminum.
[0027] The deflector likewise can be fabricated in any suitable
material, and due to its relatively complex shape will most
conveniently be manufactured as a plastic moulding, fabricated in a
material that is compatible with the refrigerant and oil employed
in the system. The preferred material is nylon however talc-filled
polypropylene is generally adequate.
[0028] Whereas in the embodiment shown in FIG. 1 the clutch cycling
switch 18 is located in the side wall 12 of the accumulator, this
switch can be positioned in a different location as required.
Likewise in the embodiment shown the service stem 20, the outlet
port 22 and the connection for the inlet tube 24 are all provided
in the top cap 16, one or more of these elements can be positioned
in different locations in the can 12 as desired, as is known in the
art.
[0029] It should be understood that while for clarity certain
features of the invention are described in the context of separate
embodiments, these features may also be provided in combination in
a single embodiment. Furthermore, various features of the invention
which for brevity are described in the context of a single
embodiment may also be provided separately or in any suitable
sub-combination in other embodiments.
[0030] Moreover, although particular embodiments of the invention
have been described and illustrated herein, it will be recognized
that modifications and variations may readily occur to those
skilled in the art, and consequently it is intended that the claims
appended hereto be interpreted to cover all such modifications and
equivalents.
* * * * *