CN106662380A - Branching means for a refrigerant flow of a refrigerant circuit - Google Patents

Abstract

A branching means for a refrigerant flow of a refrigerant circuit (10), in particular of a battery cooler circuit (30), has an inlet (52) and at least two outlet lines (58) which lead to two cooling branches (34, 36), wherein at least one throttle stage is integrated into the branching means (44).

Description

Branching device for refrigerant flow in a refrigerant circuit

technical field

The invention relates to a branching device for a refrigerant flow of a refrigerant circuit, in particular a battery cooler circuit.

Background technique

In electric or hybrid vehicles, the battery modules generate heat during operation, which is usually dissipated via a cooling circuit. Here, for cooling the battery module, it is advantageous to use the cooling subcircuit of the vehicle air-conditioning system already provided in the vehicle.

Since most battery cells are combined to form individual battery modules that are thermally decoupled from each other so that there is no heat exchange between the individual battery modules, the battery cooler circuit is typically divided into multiple cooling branches that Each is assigned to one or more battery modules. In this case, it is intended that the cooling branches flow through the refrigerant in parallel.

It is known to assign a dedicated expansion device to the battery cooler circuit, which expansion device is arranged between the outlet of the gas cooler and the inlet into a branch device which divides the refrigerant into the individual cooling branches. Here, the known thermostatic expansion valve (TXV) is used as the expansion device, which controls the refrigerant flow depending on the conditions in the battery cooler circuit. In this example, the pressure drop in the thermostatic expansion valve accounts for approximately 60% to 95% of the total differential pressure, while the pressure drop in the branch device is only 3% to 10%. The reason for this is that in the presence of high ambient temperatures, the pressure difference between the high-pressure branch and the low-pressure branch of the vehicle air-conditioning system is significantly greater than in the case of low temperatures. However, the thermostatic expansion valve must supply a sufficient amount of refrigerant to the evaporator, i.e. a sufficient flow of refrigerant, even if there is a minimum operating temperature and therefore a minimum pressure difference; It is only possible when the reduction is small. Known branching devices are therefore designed for small pressure drops.

In order to ensure the longest possible service life of the individual cells, it must be ensured that only very small temperature differences of no more than 5K exist between the individual cells. However, the small pressure drop across the branching device makes it difficult to achieve a uniform distribution of the refrigerant to the various cooling branches, which is always present in the liquid-gas mixture upstream of the branching point in the presence of relatively high temperatures. Due to the phase mixture in the branching device, known branching devices must also be installed in a precise vertical orientation in order to achieve as uniform a two-phase mixture as possible to the various outlet lines even in the presence of small throughflows distribute.

Furthermore, in the case of cooling the battery modules, the cooling arrangement has to function even in the presence of low ambient temperatures, for example down to -10°C or lower, as opposed to that of the passenger cabin, where Cooling arrangements are usually disabled at such temperatures.

However, in the presence of such low temperatures, the fraction of liquid refrigerant upstream of the branching device is essentially 100%, for which the known branching devices are not configured.

Contents of the invention

The object of the invention is to ensure a uniform cooling performance in the battery cooler circuit over the entire range of ambient temperatures, both in summer and in winter, while simultaneously reducing the costs and the size of the system.

The object is achieved by a branching device for a refrigerant flow of a refrigerant circuit, in particular of a battery cooler circuit, which branching device has an inlet and has at least two outlet lines leading to two cooling branches, At least one of these throttle stages is integrated into the branch arrangement. Since the functions of refrigerant distribution and pressure reduction are combined in one component, the structural size and manufacturing cost are reduced. With respect to known arrangements, the distance between the expansion device (i.e. the pressure reducer) and the branching device in the individual cooling branches can be significantly reduced, which results in a closer connection, in particular of the liquid part of the refrigerant, to the individual cooling branches. Evenly distributed. Thus, a uniform and sufficient supply of liquid refrigerant to the individual cooling branches of the battery cooler circuit is also ensured.

In a preferred embodiment, the throttling stage is arranged upstream of the branching point to the respective outlet line, wherein the throttling stage is in particular directly upstream of the branching point. Since the throttling point is close to the space where the refrigerant flows to the branch of each outlet line, the liquid and gas phases in the refrigerant flow remain completely mixed downstream of the throttling point, thus ensuring that the refrigerant (including refrigerant liquid portion) to the individual outlet lines for even distribution. Since the cooling performance is mainly related to the evaporation of the liquid phase of the refrigerant, a highly uniform cooling performance can be obtained in the two cooling branches.

By using a throttling stage upstream of the branching point, it has proven advantageous to use a filter directly downstream of the throttling stage in order to maintain good mixing of the liquid and gaseous phases with the refrigerant and to achieve Best possible homogenization of the two phases. In another preferred embodiment, the throttling stage is arranged downstream of the branching point to the two outlet lines. Thus, the inlet pressure of the branch device can continue to approximately correspond to the pressure of the high pressure side in the refrigerant circuit and the thermodynamic state of the refrigerant remains supercritical at least in the presence of high ambient temperatures. At the branch point itself, the refrigerant is present in a single-phase state and can thus be easily and evenly distributed to the various outlet lines without encountering the known problems with the distribution of two-phase mixtures.

The throttling stage preferably has a throttling point, i.e. a constriction of the flow cross-section, for each outlet line, said throttling points being in particular of the same form, so that the same conditions are present in all outlet lines and when supplied from said outlet lines Dominant in all cooling branches.

The throttle point of the throttle stage can be formed by a calibrated orifice. The calibrated bore is preferably formed directly in the body of the branching device and forms an integral part of each of the main line upstream of the branch point or the outlet line downstream of the branch point. The length and inner diameter of the calibrated bore can be defined very precisely and manufactured reproducibly so that the pressure drop across the throttling point can be precisely set. Furthermore, no additional components need to be used.

If the throttling stage is provided in the outlet line, calibrated bores can be formed to directly join the branch point of the main line in order to keep the structural length of the branch arrangement small.

In a further preferred embodiment, the throttle stage has a throttle point formed by an insertion tube with a calibrated inner diameter. In this example, separate tubes are inserted into the inlet, main and/or outlet lines to achieve a precise reduction of the flow cross-sectional area at the point of restriction, according to known principles of pressure reduction. Such a tube can be prefabricated in a simple and cheap manner and with high precision, and can be inserted and fastened in place in the branching device. To secure the tube in the body of the branch device, the tube may eg be inserted into a threaded sleeve screwed into the body of the branch device. This is conceivable for a throttling point in the region of the inlet of the branch device or in the region of the main line and a throttling point in the region of the outlet line. Thus, the throttle point can also be easily replaced and maintained in a simple manner.

It is advantageous to provide an end stop on the threaded sleeve, which end stop ensures precise positioning of the tube within the body of the branch device.

For calibrated bores and for tubes with calibrated inner diameters, suitable inner diameters of the throttling point are for example between 0.2 and 1.0 mm, and suitable lengths are between 10 mm and 40 mm. As the length of the choke point increases, the flow becomes more stable and less susceptible to vibrations in the flow.

In order to prevent contamination to the choke point, a filter is preferably provided upstream of the choke point.

In one possible embodiment, the two-stage pressure reduction is provided by two throttling stages connected in series with respect to flow, each throttling stage having a throttling point. In this case, the first throttle stage can be arranged upstream of the branch point in the main line or in the region of the inlet of the branch device, and the second throttle stage can be arranged in the outlet line downstream of the branch point.

The respective inner diameter of the throttle points is fixedly predetermined and cannot be changed without a structural change of the branching device for insertion of the tube.

The desired pressure drop over the branch device is set by the design of the throttle point, in particular by its arrangement, cross-section and length.

The branching device may for example contribute 10 to 50% of the total pressure drop.

In the presence of ambient temperatures of about 20°C to 40°C, ie under summer conditions, the refrigerant is preferably still substantially supercritical or liquid in a single phase only at the inlet of the branching device.

In the presence of low ambient temperatures of about -10°C to 0°C, ie during winter use, the refrigerant is preferably completely in its liquid phase at the inlet to the branch device. In this case also an even distribution to the two outlet lines can be no problem.

Preferably, the refrigerant flow has no distinctly separated phases downstream of the branching point in any operating state, so that an even distribution of the refrigerant flow to the two outlet lines is always achieved. Thus, uniform cooling of the battery modules in both cooling branches is always ensured. Furthermore, the sensitivity to deviations from the vertical mounting position is greatly reduced.

In a preferred embodiment, the branching device has two outlet lines. It goes without saying that instead of two outlet lines, three or more outlet lines may be provided in the branching device. Also, another battery cooler circuit with the same or similar structure can be connected in parallel with respect to the battery cooler circuit with said branching device

Description of drawings

The present invention will be described in more detail below based on a number of exemplary embodiments and with reference to the accompanying drawings. In the attached picture:

1 is a schematic diagram of a vehicle air conditioning system with a battery cooler system having a branching device according to the invention;

Figure 2 shows a schematic cross-sectional view of a branching device according to the invention in a first embodiment;

Figure 3 shows a schematic cross-sectional view of a branching device according to the invention in a second embodiment;

Figure 4 shows a schematic cross-sectional view of a pressure reducer with a branching device according to the invention in a third embodiment;

5 is a schematic diagram of the switching cycle of the cut-off valve of the pressure reducer of the battery cooler system;

6 is a schematic diagram of the maximum pressure differential at a pressure reducer of a battery cooler system as a function of ambient temperature;

Figure 7 is a schematic diagram of the difference in enthalpy of vaporization of R744 as a function of ambient temperature; and

Figure 8 shows the Mollier diagram of refrigerant R744 showing the operating range of the battery cooler system in the presence of low and high ambient temperatures

detailed description

Figure 1 shows a refrigerant circuit 10 of a vehicle air conditioning system (not shown in more detail). The refrigerant (R744 in this case) flows through multiple cooling sub-circuits. The refrigerant is compressed in compressor 12 and then cooled in gas cooler 14, for example by ambient air. The gaseous high pressure refrigerant then passes through internal heat exchanger 16 where it releases some of its thermal energy to the expanding refrigerant on the return flow path.

In the first cooling sub-circuit 18 , the refrigerant flows through an evaporator 20 of the vehicle's air conditioning system, for example by which the vehicle's interior cabin is cooled.

A shut-off valve 22 is arranged upstream of the evaporator 20 , by means of which the cooling subcircuit 18 can be closed off when cooling is not required. In this example, the shut-off valve 22 comprises a pressure reduction stage in the form of an opening with a reduced cross-section, which acts as a throttling point and achieves partial expansion of the refrigerant by pressure reduction.

The pressure reduction from the high-pressure side to the low-pressure side takes place here by a fixedly predetermined constriction of the cross-section, as is known for example for R744 refrigerant circuits. The diameter of the throttling point is selected inter alia in a manner dependent on the desired performance of the evaporator. The shut-off valve 22 is bridged by a bypass line 24 with a safety valve 26 . Relief valve 26 is configured to allow refrigerant flow through cooling subcircuit 18 when a critical pressure threshold is reached at relief valve 26 , which may, for example, be approximately 120-150 bar (12-15 MPa).

In general, when using R744 as a refrigerant, the refrigerant circuit must be protected from overpressure. In this case, this is achieved by means of a safety valve 26 which opens the flow connection from the high-pressure side to the low-pressure side of the refrigerant circuit in the event of a sudden pressure increase. In this case, the bypass function is available under all operating conditions. Such a pressure increase can occur, for example, in the event of strong vehicle acceleration, in which case the compressor throughput cannot be adjusted down quickly enough so that a large amount of gas is conducted into the gas cooler 14 .

Refrigerant returning from the evaporator 20 passes again through the internal heat exchanger 16 and through the accumulator 28 , any liquid refrigerant present in the accumulator 28 is separated, and the refrigerant then flows back to the compressor 12 .

Parallel to the first cooling sub-circuit 18 , the refrigerant flows through a battery cooling circuit 30 which is part of a battery cooler system 32 . The battery cooler circuit may have a cooling power of approximately 0.5 to 2 kW. The battery cells of a hybrid or electric vehicle (not shown in detail here) are arranged in a plurality of modules which are cooled by two cooling branches 34 , 36 connected in parallel. In this case, therefore, the battery cooler circuit 30 is divided into two cooling branches 34 , 36 which, after passing through the battery modules, open into a common return suction line 38 . The cooling branches 34, 36 act as evaporators in which the liquid refrigerant absorbs heat from the battery cells and thus becomes gaseous.

Downstream of the outlet of the evaporator 20 , the first cooling subcircuit 18 opens into a return suction line 38 .

A pressure reducer 40 is arranged upstream of the two cooling branches 34 , 36 . In the variant shown here, the pressure reducer 40 has a shut-off valve 42 arranged upstream of the branching device 44 .

In a possible embodiment described further below (see FIG. 4 ), the shut-off valve 42 and the branching device 44 are combined in a single component. However, they can also be formed as separate components. It is also possible to omit the shut-off valve 42 and realize the decompression entirely through the branch device 44 . The shutoff valve 42 is connected to a controller 46 which can define the opening state of the shutoff valve 42 . In this example, the shut-off valve 42 can assume only two control states "open" and "closed". In this example, a temperature sensor i is arranged directly downstream of the shut-off valve 42 , which is likewise connected to the controller 46 . Here, a second temperature sensor T2 , also connected to the controller 46 , is arranged directly at the connection point 48 of the two cooling branches 34 , 36 . 2-4 illustrate various embodiments of branching device 44 . For clarity, the reference numeral 44 has been used for all three embodiments. The branch device 44 shown in FIG. 2 has a main body 50 into which is recessed an inlet 52 which transitions into a main line 54 . At the end of the main line 54 there is arranged a branch point 56 from which the main line 54 continues into two outlet lines 58 , each of the same form in these examples. Each outlet line 58 transitions into an outlet 60 via which the respective outlet line 58 is connected to one of the two cooling branches 34 , 36 of the battery cooler circuit 30 .

A throttle stage is integrated into the branching device 44 , which throttle stage has a constriction as a throttle point and which thus enables a pressure reduction downstream of the throttle.

In the example shown in FIG. 2 , a throttling stage is achieved in each outlet line 58 by one calibrated bore 62 each having a fixedly predetermined diameter and length. In this case, the calibrated bore 62 directly joins the branch point 56 and is therefore directly downstream of the main line 54 as previously described. Instead of branching into two outlet lines 58 , branching into more than two outlet lines 58 can also be provided. Likewise, a plurality of distributors 44 may be provided in a further battery cooler circuit (not shown) connected in parallel with respect to battery cooler circuit 30 .

In this example, the throttling stage is arranged downstream of the branch point 56 . This has the effect that refrigerant in main line 54 that is completely or substantially completely in a single phase (supercritical or liquid depending on the ambient temperature, as will be described in more detail below) is split evenly between the two phases. An outlet line 58. The non-vertical mounting position of the branching device 44 also does not cause any problems due to the homogeneous aggregated state. Here, a filter 64 is provided in the inlet 52 to prevent contamination of the branching device 44 .

In these examples, the inlet 52 is formed in a connection 66 through which the branch device 44 can be connected to the piping of the battery cooler circuit 30 or to the shut-off valve 42 (see FIG. 4 ).

The calibrated bore 62 has, for example, a diameter of 0.2mm-1.0mm and a length of 10mm-40mm, wherein as the length of the throttling point increases, the flow becomes more stable and the tendency of the flow to generate vibrations is reduced. FIG. 3 shows an exemplary embodiment of the branching device 44 in which the throttle stage is arranged in the region of the main line 54 . In this case, the depressurization already takes place upstream of the branch point 56 . Downstream of the throttling point is arranged a filter 68 which homogenizes the refrigerant downstream of the throttling point by complete mixing of the liquid and gaseous fractions, thereby achieving an even distribution to the two outlet lines 58 .

In the example of FIG. 3 , the throttling point is formed by a single insertion tube 70 with a calibrated inner diameter. The inner diameter and length may be selected in the same manner as in the case of the calibrated bore 62 of the previous exemplary embodiment.

In order to fasten the tube 70 in the body 50 of the branch device 44 , a threaded sleeve 72 is provided which is screwed into the connection piece 66 of the inlet 52 . Instead of the threaded sleeve 72 it is also possible to use a plug-in sleeve which is inserted into the connection piece 66 .

The threaded sleeve 72 has an end stop 74 for precise positioning of the tube 70 in the main line 54 .

On the inlet side, the tube 70 is covered by a filter 64 which prevents contamination of the branching device 44 .

Inserts 70 of calibrated inner diameter can be produced as channels with high precision.

Instead of the insertion tube 70 , it is also possible to form a bore in the main body 50 in the main line, as described eg with respect to FIG. 2 for the outlet line 58 . Similarly, in the embodiment shown in FIG. 2 , instead of the calibrated bores 62 , it is also possible to insert one tube 70 each having a calibrated inner diameter into the outlet line 58 .

Furthermore, it is possible to provide not only one throttle point in the branch device 44, but two throttle points connected in series in terms of flow, wherein the first throttle point is arranged in the main line 54 and the second throttle point is arranged at each Each of the outlet lines 58 is formed by a constriction each.

FIG. 4 shows a pressure reducer 40 with two throttling stages connected in series with respect to flow.

In this case, the pressure reducer 40 consists of a branch device 44 and a shut-off valve 42 , which are screwed together via a connection piece 66 of the branch device 44 . In this example, the branching device 44 corresponds to the branching device 44 shown in FIG. 2 . However, a branching device according to the embodiment shown in Fig. 3 or some other suitable branching device 44 could also be used.

In this example, shutoff valve 42 is switched by electromagnet 76 , which is connected to controller 46 of battery cooler system 32 . By means of an electromagnet 76, the shut-off valve 42 is switched between its two switching states "open" and "closed", wherein the flow of refrigerant through the inlet 78 of the shut-off valve 42 is either completely permitted or completely stopped.

Immediately downstream of the valve seat 80 of the shut-off valve 42 , a first throttle stage is implemented, in this example via a calibrated bore 82 , which forms a flow cross-section for the refrigerant. of the constriction. The cross-section of the calibrated bore 82 is narrowed relative to the cross-section of the inlet 78 and also narrowed relative to the cross-section of the adjacent inlet 52 of the branching device 44 . In this way, a first expansion and a first decompression of the refrigerant are achieved in the calibrated bore 82 . In the branch device 44 a second throttling stage is formed, in this example by a constriction formed by a calibrated bore 62 in the outlet line 58 , which achieves a second depressurization of the refrigerant and further expansion.

Instead of a calibrated bore 82 in the body of the shut-off valve 42 it is also possible to provide a calibrated bore or tube 70 with a calibrated inner diameter in the inlet 52 of the branch device 44 . In this way, the construction of the shutoff valve 42 can be further simplified.

The refrigerant flows from the outlet line 58 into the two cooling branches 34 , 36 of the battery cooler circuit 30 .

In the embodiment shown in FIG. 1 , the battery cooler system 32 is configured such that in "winter conditions" in the presence of low ambient temperatures, ie temperatures between about -10°C and 0°C , a pressure difference of about 10 bar and an enthalpy difference of about 240 kJ/kg are obtained over the pressure reducer. The pressure difference can also be configured with respect to the pressure difference between the high-pressure side and the low-pressure side of the entire refrigerant circuit 10 . These parameters are achieved by a specific design of the throttle stage of the pressure reducer 40 .

It is important that the refrigerant flow achieved by the cross-sectional constriction in the throttle stage is large enough to provide sufficient cooling performance for the battery modules in the battery cooler circuit 30 even at low ambient temperatures. Under these ambient conditions, the phase boundary to the supercritical state exceeds only about 1 to 5 Kelvin (see also Figure 8).

At prevailing ambient temperatures in summer, ie at temperatures up to approximately +40° C., considerable pressure differences exist between the high-pressure side and the low-pressure side of the refrigerant circuit 10 and of the battery cooler circuit 30 . In order to prevent an excessive flow of liquid coolant through the branch device 44 under such conditions, the shut-off valve 42 is operated in a pulsed manner, wherein the excessive flow of liquid coolant will not be able to evaporate completely in the cooling branches 34, 36, and The cooling performance of the evaporator 20 for air conditioning of the passenger compartment is thus reduced.

This is shown schematically in FIG. 5 . The solid line curve shows that in the case of high ambient temperatures the shut-off valve 42 is operated with pulse width modulation by the controller 46 so that the cooling performance is optimized. The opening duration of the shut _- off valve 42 is determined by the controller 46 from the value of the signals sent by the temperature sensors T1 and T2, namely from the temperature _of the refrigerant at the inlet 52 of the branch device 44 and after the refrigerant has passed through the battery The temperature of the refrigerant after the cooling branches 34 , 36 of the cooler circuit 30 is calculated.

The time period during which the shut-off valve 42 remains closed between two open states may be 30 seconds or more; this also applies to the time period during which the shut-off valve 42 is open between closing phases. This is possible because the battery cooler circuit 30 with the battery modules has a higher thermally active mass than, for example, the evaporator 20 of the vehicle air conditioning system.

In winter, that is to say in the presence of low ambient temperatures and small differential pressures, the reverse is the case when the shut-off valve 42 is permanently open (see dashed line in FIG. 5 ).

6 and 7 show the pressures prevailing on the high-pressure side and on the low-pressure side of the refrigerant circuit 10 as a function of the ambient temperature. The pressure distribution on the high pressure side is represented by diamonds, while the pressure distribution on the low pressure side is represented by squares. From Figure 6, it can be seen that under winter conditions where there is an ambient temperature between , there are significantly higher differential pressures, for example 35 bar to 65 bar (3.5 to 6.5 MPa), wherein a differential pressure of 90 bar can even exist. From this measurement, the optimal configuration of the pressure reducer 40 can be calculated for the existing battery cooler system 32 in the refrigerant circuit 10 . To this end, the enthalpy difference during evaporation of the refrigerant (in this example, R744), which is plotted in Figure 7 as a function of the ambient temperature, must also be taken into account.

The pressure difference between the high-pressure side and the low-pressure side increases greatly as the ambient temperature increases. Since the resulting mass flow varies approximately with the square root of the differential pressure, for example for an ambient temperature of -10° C. the possible cooling performance of the battery cooler circuit 30 is reduced by approximately 40% relative to an ambient temperature of +40° C. If the battery cooler system 32 and particularly the pressure reducer 40 are optimized for operation at low ambient temperatures, this has the effect that during operation where high ambient temperatures are present, the shutoff valve 42 should be at about 30%-90% closed in time.

The configuration of the rest of the refrigerant circuit 10, in particular the cooling sub-circuit 18 for the evaporator 20 of the vehicle air conditioning system, is not affected by these considerations since only the pressure reducer 40 in the battery cooler circuit 30 must be constructed accordingly. Fig. 8 shows the cycles through which the operation of the refrigerant circuit 10 is performed under summer conditions (high ambient temperature) and winter conditions (low ambient temperature) based on a Mollier diagram.

The upper cycle in the graph (points A to G) describes operation in the presence of high ambient temperatures. The high pressure side, in this case preferably between 80 and 120 bar, operates in the supercritical range. From point A to point B, compression of the refrigerant occurs in compressor 12 . From point B to point C, the supercritical refrigerant is cooled in gas cooler 14 . From point C to point D, further cooling on the high pressure side of the refrigerant circuit 10 is achieved by means of the internal heat exchanger 16 . From point D to point E, decompression occurs in the first throttling stage of pressure reducer 40, where decompression occurs at most up to the liquid boundary, so that the refrigerant remains only in single-phase form or in super Critical state. From point E to point F, a further depressurization takes place in a second throttling stage of the pressure reducer 40 , in this example in the outlet line 58 of the branching device 44 . From point F to point G, cooling of the battery modules in the cooling branches 34 , 36 of the battery cooler circuit 30 occurs where the refrigerant is evaporated and absorbs heat from the battery modules. Finally, from point G to point A, the refrigerant flows through internal heat exchanger 16 via return suction line 38 back to compressor 12, where it absorbs heat from the high pressure branch. In winter operation (lower cycle in Figure 8, points a-f), the same cycle is performed below the critical point. From point a to point b, the refrigerant is compressed, and from point b to point d, the refrigerant is cooled. After the expansion of the refrigerant in the first throttling stage of the pressure reducer 40 (point d to point e), the refrigerant is completely in the liquid phase. The refrigerant has a gaseous part only when it passes through the second throttling stage (point e to point f).

However, in the examples described herein, the refrigerant is still only in a single-phase form when it branches off 44 . In this way, an even distribution to the two cooling branches 34 , 36 is easier to achieve than in the presence of a mixture of phases.

Claims (10)

1. one kind is used for the branch unit of the refrigerant stream of cryogen circuit (10), and the cryogen circuit is particularly battery cooler Loop, the branch unit has import (52) and with least two outlets for leading to two cooling branch roads (34,36) Line (58), wherein at least one throttling level is integrated in the branch unit (44).

2. branch unit according to claim 1, it is characterised in that the throttling level is arranged into two outlet lines (58) Branch point (56) upstream.

3. branch unit according to claim 2, it is characterised in that filter (68) is arranged under the throttling level Trip.

4. branch unit according to claim 1, it is characterised in that the throttling level is arranged in two outlet lines (58) Branch point (56) downstream.

5. branch unit according to claim 4, it is characterised in that throttling level tool in each outlet line (58) There is contraction flow region.

6. the branch unit described in aforementioned claim, it is characterised in that the throttling level has by calibrating Duct (62) formed throttle point.

7. branch unit according to claim 6, it is characterised in that the duct (62) of the calibration is formed as directly engagement The branch point (56) of Trunk Line (54).

8. the branch unit according in claim 1 to 6, it is characterised in that the throttling level has by with school The throttle point that the insertion tube (70) of accurate internal diameter is formed.

9. branch unit according to claim 8, it is characterised in that the pipe (70) be inserted into screw shell (72) or In plug-in type sleeve, the sleeve is screwed into or is inserted in the main body of the branch unit (44) (50).

10. the branch unit described in aforementioned claim, it is characterised in that first throttle level is arranged in described The upstream of branch point (56), and the second throttling level is arranged in the downstream of the branch point (56).