Note: Descriptions are shown in the official language in which they were submitted.
CA 02890872 2015-05-11
Device and method for maintaining an air conditioner
The present invention relates to a device for maintaining an air conditioner,
in particular,
for air conditioners using CO2 or R744 as a coolant, and the device has a low-
pressure
side region, which is connectable to a service port on the low-pressure side
of the air
conditioner via a low-pressure side coupler, and a high-pressure side region,
which is
connectable to a service port on the high-pressure side of the air conditioner
via a high-
pressure side coupler, and a compressor is provided between the low-pressure
side
region and the high-pressure side region. Furthermore, the present invention
relates to a
method for operating a service device for air conditioners.
Independent of the used coolant, an air conditioning service has the task to
empty,
evacuate, and then to refill the air conditioner again with the right amount
of coolant and
oil. Modern service devices, for example, those used for air conditioners in
motor
vehicles, conventionally have two service ports, one being connected to the
high-
pressure side of the air conditioner and the other to the low-pressure side.
In this way, a
circuit is formed that conventionally leads from the low-pressure side
connector via an
oil separator, an evaporator, a compressor and a condenser to the high-
pressure side
connector. Furthermore, empty and fill devices for suctioning the mixture of
coolant and
compressor oil out of the coolant circuit and refilling the air conditioner
with coolant and
compressor oil are provided in the service device. For this purpose, the
circuit mixture is
suctioned out in a first phase via a separation stage, for example an oil
separator or a
filter. Subsequently, the circuit system is emptied almost completely of
residual content
by a vaccum pump and, then, new coolant and new oil are added from a storage
container to the system.
Systems and methods for maintaining air conditioners are, for example, known
from the
publications WO 2011/088831 Al, DE 202008003123 U1, or DE 102009054436 Al.
When emptying the air conditioning circuit, one problem is that the coolant,
when
relaxing rapidly in the wet steam region, may solidify below a pressure
threshold. For
CO2 or R744 as a coolant, the threshold for CO2 to solidify to dry ice in the
wet steam
region is at a pressure of 5.18 bar. In order to prevent CO2 from freezing, a
relaxation to
approximately 18 bar, therefore, may be carried out in a first step and, then,
one waits
until the CO2 in the vehicle is completely evaporated before the suctioning
may be
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continued.
The present invention is based on the idea to create a device and a method by
which the
problems of the related art mentioned above may be alleviated. In particular,
an
object of the present invention is to shorten the time required to empty the
air
conditioner.
According to the present invention, this and further objectives are achieved
by a device
mentioned at the outset that provides, between the compressor and the high-
pressure
side region, an over-pressure region, which is connected to the high-pressure
side
region via a throttling device. On the gas side of the phase diagram, the
achievable over-
pressure enables a more effective procedural utilization of the region outside
of the wet
steam curve of the coolant. Within the context of this present invention, any
device that
is able to execute the pressure-controlling function of a throttle is referred
to as a throttle
device, These include, for example, an expansion valve, a fixed throttle, an
orifice having
a bypass or an orifice not having a bypass, etc.
According to an aspect of the present invention, there is provided a device
for
maintaining an air conditioner, the device comprising: a low-pressure side
region,
which is connectable to a service port on a low-pressure side of the air
conditioner
via a low-pressure side coupler; and a high-pressure side region, which is
connectable to a service port on a high-pressure side of the air conditioner
via a
high-pressure side coupler,
wherein a compressor is provided between the low-pressure side region and
the high-pressure side region, and
wherein between the compressor and the high-pressure side region, an over-
pressure region is provided, which is connected to the high-pressure side
region via
a throttle device.
According to an aspect of the present invention, there is provided a method of
operating a service device for an air conditioner, wherein the service device
for
establishing a circuit is, via a low-pressure side coupler and a high-pressure
side
coupler, connected to a low-pressure side or a high-pressure side of the air
conditioner, and wherein the method comprises transferring a coolant in the
air
conditioner from a phase state 11 within a wet steam curve via a circuit
process to a
phase state 112 outside of the wet steam curve, wherein a specific enthalpy in
phase
state 112 has a value which isenthalp lays completely outside of the dry ice
region.
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A vacuum pump, which may evacuate the fluid system of the unit or individual
regions
thereof, may be connected in an advantageous manner to the low-pressure side
region.
In an advantageous embodiment of the present invention, a circuit fluid
connection may,
starting from the low-pressure side coupler, be released by valves to the high-
pressure
side coupler via the low-pressure side region, the compressor, the region of
over-
pressure, the throttle device, and the high-pressure side region. This circuit
fluid
connection enables to condition the coolant located in the system very rapidly
in a circuit
process and in such a manner that a formation of dry ice is prevented during
draining.
In a further advantageous embodiment, a storage container, which is
connectable to the
over-pressure region and/or the low-pressure side region via valves, may be
provided in a
storage region. For this purpose, the storage container may be used for
storing the out-
pumped coolant and also for providing the coolant to be in-pumped.
Furthermore, an out-pumping fluid connection may, starting from the low-
pressure side
coupler, be released by valves to the storage container via the low-pressure
side region,
the compressor, and the over-pressure region. In this way, coolant suctioned
out of the air
conditioner may be processed and stored for reuse in the storage container.
In a further advantageous embodiment an in-pumping fluid connection may,
starting
from the storage container, be released by valves to the high-pressure side
coupler via
the the compressor, the over-pressure region. and the high-pressure side
region. In
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doing so, the coolant may, using the compressor, be pumped from the storage
container
into the air conditioner via the high-pressure side connection. Preferably,
the coolant in
the over-pressure region may be cooled by a gas cooler in this instance and
the amount
pumped in may be measured using a flow rate meter.
According to an advantageous embodiment, drain valves may, according to the
present
invention, be connected at the low-pressure side region and/or at the high-
pressure side
region. This enables to drain coolant, for example, CO2, into the environment.
In an advantageous embodiment, a new oil container may be connected to the
fluid
system via a new oil valve. This enables to refill new oil into the air
conditioner in a
simple manner. Within the context of the present description, fluid system
refers to all
conduits and components of the device in its entirety and, if applicable, to
the air
conditioner connected thereto, in which the fluid may be situated as coolant
or through
which the coolant may flow.
Preferably, an oil separator and/or evaporator and/or filter dryer may be
provided in the
low-pressure side region and a fluid separator and/or a gas cooler and/or a
flow rate meter
may be provided in the over-pressure region. These features enable an
advantageous
conditioning of the coolant. In particular, old oil and pollutants may be
removed from the
coolant. The flow rate meter enables an accurate measurement of the amount of
coolant.
An advantageous embodiment of the device according to the present invention
may
provide that, in the region of over-pressure between the compressor and the
gas cooler,
a switch valve is provided, which is able to reroute the circuit fluid
connection to a
bypass circumventing the gas cooler. Therefore, one single compressor may be
used for
the circulation step (via the bypass) and also for pumping the coolant in and
out
(respectively via the gas cooler).
The method according to the present invention for operating a service device
for air
conditioners, in particular, for air conditioners using CO2 or R744 as
coolant, is
characterized by the fact that the service device for forming a circuit via a
low-pressure
side coupler and a high-pressure side coupler is connected to the low-pressure
side or
the high-pressure side of the air conditioner, respectively, and the method
features the
step of transferring the coolant in the air conditioner from a phase state II
within the wet
steam curve via a circuit process to a phase state IIE outside of the wet
steam curve, and
the specific enthalpy in phase state HE has a value which isenthalp lays
completely
outside of the dry ice region. Proceeding from phase stage 11E, the coolant
may be
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drained without forming dry ice.
Within the context of the present invention, circuit process refers to a
process step in
which the coolant is left circulating in the circuit. With regard to the phase
change, this
process is not closed looped because the aimed-at endpoint of the state change
(phase
state 11E) does not correspond with the initial state (phase state II). For
example, a basic
circulation unit having a gas pump and a heat supply, for example, a heat
exchanger,
could carry out the circuit process because this would suffice to increase the
enthalpy of
the coolant. Particularly advantageous, however, is utilizing the device
according to the
present invention herein described for maintaining an air conditioner.
In an advantageous manner, the circuit process starting from phase state II
may include
the following state changes: isobaric heating of the coolant to outside of the
wet steam
curve; isentropic compression to an over-pressure above the pressure of the
initial
phase state II and, preferably, above the critical pressure of the coolant;
isenthalpic
expansion; and mixing with the coolant in the air conditioner. This
illustrates a basic
circuit process, which may be realized using an evaporator, a compressor, and
a throttle
device.
Before the step of the circuit process, the method according to the present
invention
may have the following steps: evacuating a sealed-off region of the service
device that
connects at the low-pressure side of the air conditioner and that is separated
from said
low pressure side by a closed valve; and opening of a fluid connection between
the
evacuated region of the service device and the fluid system of the air
conditioner. In this
way, the circuit process may be started from a convenient phase state II
resulting after
a first expansion of the coolant.
In an advantageous manner, the method may, after the circuit process, feature
the step
of pumping the coolant out of the air conditioner into a storage container.
The coolant
may, according to the respective circumstances and the legal requirements,
either be
completely drained from the air conditioner or stored for recycling.
In a preferred embodiment, old oil may be separated during the method and the
amount
of the old oil separated from the air conditioner may be determined. This way,
the
amount of new oil for refilling the air conditioner may be determined.
A further advantageous embodiment of the method may feature the step of
evacuating the
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CA 02890872 2015-07-24
system after draining and, if applicable, out-pumping the coolant with a
vacuum pump. The
evacuation of the unit enables to test for leaks. Simultaneously, water is, if
applicable,
evaporated in the unit and removed from the circuit.
After removing the coolant and before refilling the air conditioner, new oil
may be brought
into the evacuated fluid system in an advantageous manner, and the amount of
new oil
may be determined on the basis of the amount of separated old oil. In this
way, a simple
and accurate dosage of the amount of new oil via a basic valve is possible. As
the new oil
is suctioned in by the vacuum, a pump is not required. During the subsequent
filling the oil
is carried by the coolant and, in this manner, reaches the air conditioner.
In the following, the present invention is described in detail on the basis of
an exemplary
embodiment in reference to the appended drawings, which, in an exemplary
manner,
schematically and non-restrictively show advantageous embodiments of the
present
invention, and
Figure 1 shows a circuit diagram of a servie device;
Figures 2A-2C show in a schematic illustration a plurality of fluid
connections,
which may be produced by switching valves;
Figure 3 shows the phase changes of the circulation step in a p-h diagram of
R744.
Figure 1 shows an embodiment of the service device in a circuit diagram, and
the fluid
system of the device may be separated into four regions: a low-pressure side
region A, an over-pressure region B, a high-pressure side region C, and a
storage
region D.
The low-pressure side region A starts at the low-pressure side coupler 1,
which connects
the service device to the low-pressure side of the motor vehicle air
conditioner. From the
low-pressure side coupler 1, the pipe preferably runs inside a hose to a first
shut-off
valve 101, and measuring devices 16 are provided for the pressure and the
temperature
upstream of shut-off valve 101. When connecting the low-pressure side coupler
to the air
conditioner, shut-off valve 101 is closed and measuring devices 16 measure
the values for the air conditioning medium on the low-pressure side of the air
conditioner
An oil separator 2 is situated after shut-off valve 101 and, after an
additional shut-off
valve 102, the pipe leads via an evaporator 3 and a filter dryer 11 to an
additional valve
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103, which may be understood as the end of low-pressure side region A.
The oil from the air conditioner separated by oil separator 2 is collected in
an old oil
collection container 14 and is weighed by a scale to determine the amount of
oil to be
refilled.
Two connectors are located between evaporator 3 and filter dryer 11, the first
connector
leading to a shut-off valve 106, which is provided as a barrier to storage
region D. The
second connector leads via a shut-off valve 109 to a vacuum pump 10.
An additional connector leading to a first drain valve V1, via which the
coolant is able to
be released into the environment, is provided between the filter dryer 11 and
valve 103.
A compressor 4 running into over-pressure region B is provided after valve 103
at the end
of the low-pressure side region A. A liquid separator 12 , which serves to
regain oil and
operating means of the compressor carried by the coolant and to be fed back to
the
compressor, is provided in over-pressure region B after compressor 4. Safety
valve 13
limits the system pressure to counteract possible destructions by possible
defects and,
thus, excessive pressure. After liquid separator 12, the fluid stream may be
led by a
switch valve 6 either via flow rate meter 8 and a gas cooler 7 or via a bypass
17
circumventing the flow rater meter and the gas cooler. A shut-off valve 104 is
also located
at the end of over-pressure region B and, after said valve, the pipe leads to
a throttle
device 5 situated between over-pressure region B and subsequent high-pressure
side
region C. A connector leading to a second drain valve V2 is provided between
shut-off
valve104 and throttle device 5. A controlled expansion valve is used as
throttle device 5 in
the illustrated embodiment. The throttle device may also be realized in a
different manner,
for example, by an orifice having a bypass or an orifice not having a bypass,
or a fixed
throttle in conjunction with a rotation-controlled compressor.
High-pressure side region C starting after throttle device 5 has a shut-off
valve 105 and
measuring devices 16', via which the pressure and the temperature may be
measured
at the supply hose leading to the high-pressure side of the air conditioner. A
connector
leading via a new oil valve 110 to a new oil container 15 is provided between
throttle
device 5 and shut-off valve 105. High-pressure side region C ends at high-
pressure side
coupler 1', which connects the service device to the high-pressure side of the
air
conditioner.
As can be seen from Figure 1, by opening connection valves 101 and 105 and
inboard
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valves 102, 103, and 104, a continuous fluid connection, leading from low-
pressure side
coupler 1 via oil separator 2, evaporator 3, filter dryer 11, compressor 4,
liquid separator
12, switching valve 6 switched to bypass 17, bypass 17, and throttle device 5
to high-
pressure side coupler 1', may be established between low-pressure side coupler
1 and
high-pressure side coupler 1'. In the following, this path is referred to as
circuit fluid
connection 201, which is illustrated schematically and in a highly simplified
overview once
more in Figure 2k Circuit fluid-system 201 forms, in conjunction with the
pipes of the air
conditioner, a continuous circuit system. It shall be noted that circuit fluid
connection 201
circumvents gas cooler 7 situated in the over-pressure region in that switch
valve 6 is
switched in the direction of bypass 17. The functional relevance of circuit
fluid connection
201 is explained in detail within the context of the description of the method
according to
the present invention.
The fourth region of the device is storage region D, made up of a storage
container 9 and a weighing unit 19 situated at said storage container 9. The
pipe
running into storage container 9 may be shut off by a shut-off valve 108. A
first pipe
leads from storage region D via shut-off valve 106 to low-pressure side region
A and a
second pipe leads via shut-off valve107 to over-pressure region B, and this
pipe runs
into the outlet of gas cooler 7.
As it is clear to a skilled person, using valves 101-110 , V1 and V2, and
switch valve 6, a
plurality of different fluid connections may be realized by the components and
pipes of the
device illustrated in Figure 1. By opening valves 101,102,103, 107, and 108
and switching
switch valve 6 in the direction of flow rate meter 8 and gas cooler 7, for
example, a drain
fluid connection 202 may be established, via which the coolant from the air
conditioner is
able to be pumped from compressor 4 via gas cooler 7 into storage container 9.
Drain fluid
connection 202 is schematically illustrated in Figure 2B.
By opening valves 108,106,103, 104, and 105 and switching switch valve 6 in
the
direction of flow rate meter 8 and gas cooler 7, for example, an in-pumping
fluid
connection 203 may be established, via which compressor 4 is able to pump
coolant
out from storage container 9 via flow rate meter 8, gas cooler 7, and throttle
device 5
into the high-pressure side of the air conditioner. In-pumping fluid
connection 203 is
schematically illustrated in Figure 2C.
A method, by which the maintenance device illustrated in Figure 1 may be used
in an
advantageous manner for carrying out a coolant exchange in an air conditioner
of a
motor vehicle, is explained hereafter in an exemplary manner.
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First, low-pressure side coupler 1 and high-pressure side coupler 1' are
connected to
respective service ports of the air conditioner of the motor vehicle, and
connection valves
101 and 105 are closed. Low-pressure side coupler 1 and high-pressure side
coupler 1'
are located respectively at the end of a connection hose 20, 20, which is able
to easily
reach the service ports in the car. Preferably, a combined connector may also
be used,
by which both connectors may be connected to the air conditioner in a single
process
step. As soon as the connection is established, the mixture of coolant and
compressor
oil located in the air conditioner flows into connection hoses 20, 20', and an
equilibrium
state is established, the pressure and the temperature of the coolant being
displayed on
measuring devices 16,16'. In a typical, exemplary air conditioner of a motor
vehicle
having R744 as coolant, the CO2 in the air conditioner has, after an
equilibrium state has
been established at room temperature (approximately 20 C), a pressure in the
region of
60 bar. The filling degree of the unit for a full air conditioner of a motor
vehicle is
conventionally in the region of maximally 260 kg/m3 or, if applicable, below.
It is to be noted that the operating pressures of the air conditioner (which
conventionally
are, for example, at approximately 130 bar on the high-pressure side and
approximately
40 bar on the low-pressure side) do not play a role when maintaining the unit
because
the compressor of the air conditioner (and the gas cooler and the evaporator
of the air
conditioner) is deactivated during service. When, within the context of this
application,
the term high-pressure side of the air conditioner is used, merely the pipe
section of the
air conditioner is meant that is located between the compressor and the
throttle of the
air conditioner and that runs via the gas cooler and, in the case of CO2 as
coolant, the
inboard heat exchanger of the cooling system. As it is clear to a skilled
person, when
the compressor is standing still, the entire circuit of the air conditioner
rapidly adjusts
substantially the same pressure and phase state. This idle phase state lies,
in the
present example, at approximately 20 C, 250 kg/m3 and 57 bar and is
referenced as
point I in the phase diagram of Figure 3.
After connecting the service device, inboard valve 102 and vacuum pump valve
109 are
opened and the volume of oil separator 2 is evacuated by the vacuum pump.
Subsequently, after closing vacuum valve 109, shut-off valve 101 is opened,
leading to
that the coolant of the air conditioner flows into the oil separator. The
change state taking
place in this instance can be recognized as an isenthalpic expansion between
the points I
and II in the diagram of Figure 3. In the illustrated example, point II is
approximately at
-2 C and 33 bar, and resulting in approximately doubling the volume.
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If one would now, proceeding from point II, start to drain the coolant via
drain valves V1
and V2 (or to pump it into the storage container) and, by doing so, rapidly
relax said
coolant, the coolant would solidify to dry ice at a pressure of 5.18 bar (at a
temperature
of approximately -59 C). Therefore, it so far has been common practice to
wait, after a
first relaxation to approximately 18 bar, until the CO2 has completely
evaporated in the
cooling circuit. Subsequently, the drain or suction process may be continued
now outside
of the wet steam region.
The device according to the present invention makes it now possible to prevent
this wait
time and, thus, to shorten the complete duration required for the service. For
this purpose,
circulation fluid connection 201 (according to Figure 2A) is established in
the next step by
respective switching of the valves. Subsequently, the coolant is circulated in
circulation
fluid connection 201 via compressor 4, and the coolant runs sequentially from
low-
pressure side coupler 1 to high-pressure side coupler 1' through the following
phases
(Figure 3) or components (Figure 1):
Old oil carried by the coolant is separated in oil separator 2 and is
collected in an old oil
container 14. The amount of the collected old oil may, for example, be
determined by a
scale.
In the evaporator, the CO2 is heated isobarically out of the wet steam curve
(state
change from point II to point III in Figure 3) and, thereafter, runs through a
filter dryer in
order to remove potential pollutants or humidity. In the present example, the
coolant at
point Ill has a pressure of approximately 33 bar and a temperature of
approximately
15 C.
Compressor 4 compresses the coolant isentropically to a supercritical
pressure of approximately 90 bar, and the pressure is controlled by throttle
device 5
(state change from point III to point IV in Figure 3). The temperature at
point IV is
approximately 100 C. Liquid separator 12 serves to lead swept-away oil of
compressor
4 back to said compressor.
Via switch valve 6 and bypass 17, the coolant directly reaches throttle device
5 in
circumventing gas cooler 7, in which an isenthalpic expansion (from point IV
to point V in
Figure 3) to a pressure of approximately 67 bar and a temperature of
approximately
80 C occurs.
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Then, a mixing with the coolant located in the accumulator of the air
conditioner takes
place in the air conditioner, and the coolant initially has the original phase
state (point II
in Figure 3). The mixing changes the phase state in the air conditioner at
constant
compression, and the phase state shifts to mixing point II', which in the
diagram is
indicated at approximately 4 C and approximately 38 bar. Mixing point 11' only
represents
a virtual point because, in the actual circuit process, this point constantly
shifts along the
isodenses (at approximately 125 kg/m3).
Starting from mixing point II', the further course of the circuit process via
the points III'
(15 C, 38 bar), IV (85 C, 90 bar), V' (61 C, 61 bar) to the next mixing
point II"
(approximately 10 C, 43 bar) is indicated.
The circuit process is carried out until a phase state according to point IIE
is reached in
the air conditioner, and this point lies at an enthalpy which isenthalp lies
completely
outside of dry ice region 21. The precise position of end point IIE is highly
dependent on
the original filling degree of the unit and lies preferably at a specific
enthalpy of
approximately 450 kJ/kg or above. Proceeding from point 11E, the CO2 may be
drained
and out-pumped without the coolant freezing.
Via measuring devices 16, 16', a value pair for the pressure and the
temperature in the
circuit may be read-out during the circuit process, from which it may be
determined
whether a sufficient enthalpy for draining is already reached at the specified
filling
degree. For this purpose, it is not compulsory to precisely know the actual
filling degree
(thus, the compression) of the unit. If the maximum filling degree is used as
reference
value for the method, the same circuit process would, in the case that the
filling degree
were actually lower, merely result in an end point IIE having a higher
enthalpy, so that a
freezing in the subsequent drain step still is not a concern.
For the illustrated circuit process it is assumed that neither the mass of the
circulating
coolant nor the volume of the fluid system changes and, thus, the compression
of the
cooling medium (considering the overall system in its state of equilibrium)
remaining
constant during the circuit process. For this reason, phase states 11, 11',11"
through IIE in
Figure 3 are located on the same isodense. It might, however, also be possible
to drain
a portion of the coolant during the circuit process, for example, by opening
drain valve
V2 in a controlled manner, in order to reach a point 11E, at which the coolant
has a
different compression than at point II. For example, it might be achieved that
all points
II, II', II" through IIE are located on one isobar. In this way, the method
according to the
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CA 02890872 2015-05-11
present invention might also be realized by less powerful compressors that
exhibit a
lower performance and are, for example, suitable only for nominal pressures of
only 80,
70, 60 bar or less.
Draining may occur by opening drain valves V1, V2; however, the device
according to
the present invention also enables to collect the coolant and to make it
accessible to a
recycle. For this purpose, inboard valve 104 is closed between over-pressure
region B
and high-pressure side region C and switch valve 106 is switched to the side
of gas
cooler 7. By opening shut-off valve 106 on the over-pressure side and storage
container
valve 108, a drain fluid connection 202 is able to be formed, which leads from
low-
pressure side coupler 1 via oil separator 2, evaporator 3, filter dryer 11,
compressor 4,
liquid separator 12, switch valve 6, flow rate meter 8, and gas cooler 7 to
storage
container 9. Now, compressor 4 is able to pump the coolant via low-pressure
side
coupler 1 out of the circuit of the air conditioner into the storage
container.
After out-pumping the coolant, storage container valve 108 is closed and the
remaining
CO2 is drained via drain valves V1 and V2 until the pressure in the unit has
been lowered
to ambient pressure. Subsequently, connection valves 101, 105, inboard valves
102, 103,
104 and vacuum pump valve 109 are opened and the system is evacuated via
vacuum
pump 10, and the vacuum pump is able to reach a pressure in the order of
approximately
1 mbar. Water possibly situated in the unit may evaporate also at this
pressure and is
suctioned out together with the remaining coolant via vacuum pump 10.
Now that the system has been completely evacuated, the amount of compressor
oil
collected in old oil collection container 14 is measured and a respective
amount of new
oil is brought, by opening new oil valve 110 in a controlled manner into high-
pressure
side region C from new oil container 15. The vacuum dominating in the system
results in
that the oil is suctioned into the system without further action. In the
subsequent in-
pumping step, the inflowing coolant then flushes the oil into the circuit of
the air
conditioner.
For subsequently refilling the air conditioner, inboard valves 103, 104, 105
are then
opened and the switch valve is switched in the direction of gas cooler 7.
Furthermore,
low-pressure side shut-off valve 106 and storage container valve 108 are
opened, so that
in-pumping fluid connection 203 is established, which leads from storage
container 9 via
filter dryer 11, compressor 4, liquid separator 12, switch valve 6, check
valve 18, throttle
device 5, and high-pressure side coupler 1' into the high-pressure side of the
air
conditioner. Then, compressor 4 pumps CO2 from the storage container via in-
pumping
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fluid connection 203 into the air conditioner, and the amount of the coolant
to be pumped
in is measured in flow rate meter 8, in order to fill the required amount of
coolant into the
air conditioner according to manufacturers' instructions. For this purpose,
the high
pressure of the compressor is controlled by throttle device 5. When in-
pumping,
connection valve 101 and first inboard valve 102 remain closed, so that the
oil separator
is not filed with coolant.
After in-filling, connection valve 105 is closed and couplers 1 and 1' are
detached from
the service ports of the air conditioner.
As a variation of the special exemplary embodiments illustrated in the
figures, merely
serving the purpose of explaining the present invention, the device according
to the
present invention may also be carried out in a plurality of other manners. In
particular,
the arrangement of components may be changed and specific components may also
be
completely removed, provided that the functionality and the execution of the
method
according to the present invention are not impacted.
For example, the order of oil separator 2 and evaporator 3 may be exchanged
without
impacting functionality. Flow rate meter 8 is not compulsory as the filling
amount may, as
known in professional circles, be determined differently, for example, by
measuring the
masses of the coolant bottle when simultaneously compensating for the amount
of coolant
in the service unit. The flow rate meter also may be situated in a different
location in the
system.
Filling the air conditioner of the motor vehicle and, if applicable, also the
recycling in a
bottle might be carried out also by a simplified system, in which a gas cooler
7 is not
provided. If the CO2 is not to be fed to a recycle, switch valve 6 would also
not be
necessary and valves 107 and 108 could also be omitted, and the flow rate
meter could,
if applicable, be situated in the circuit upstream of valve 104.
According to the present invention, skilled people may, without any innovative
intervention, create a plurality of modified embodiments without deviating
from the
scope of protection of the appended claims.
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CA 02890872 2015-05-11
Reference characters:
Low-pressure side coupler 1
High-pressure side coupler 1'
Oil separator 2
Evaporator 3
Compressor 4
Throttle device 5
Switch valve 6
Gas cooler 7
Flow rate meter 8
Storage container 9
Vacuum pump 10
Filter dryer 11
Liquid separator 12
Safety valve 13
Old oil collection container 14
New oil container 15
Measuring devices 16, 16'
Bypass 17
Check valve 18
Weighing unit 19
Connection hose 20, 20'
Dry ice region 21
Connection valves 101, 105
Inboard valves 102, 103, 104
High-pressure side and over-pressure side shut-off valve 106, 107
Storage container valve 108
Vacuum pump valve 109
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CA 02890872 2015-05-11
New oil valve 110
Drain valves V1, V2
Circulation fluid connection 201
Out-pumping fluid connection 202
In-pumping fluid connection 203
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