DE102021129383A1 - Pressure equalization and volume equalization in the cooling circuit - Google Patents

Abstract

Cooling arrangement (8) for cooling an object (4), with a cooling circuit (10) for an incompressible fluid (12), with an expansion tank (16) on the cooling circuit (10) with a fluid space (20) for the fluid (12), wherein the expansion tank (16) has a rigid first wall section (28a) and a second wall section (28b) which together delimit the fluid chamber (20), with at least a part of the second wall section (28b) as a movement area (34) relative to the first wall section (28a) is movable in order to change the volume (VR) of the fluid chamber (20), wherein A) the second wall section (28b) is designed to be rigid overall as a movement area (34) and movable relative to the first wall section (28a), and/ or B) a shape of the movement range of the second wall section can be changed.An object arrangement (6) contains the cooling arrangement (8) and the object (4).An aircraft (2) contains the object arrangement (6), the aircraft (2) in the Flight is powered by the electrical energy generated from the fuel cells as part of the object and/or whose power grid is fed by the fuel cells.

Description

The invention relates to a cooling arrangement for cooling an object. The cooling arrangement contains a cooling circuit/coolant circuit for cooling the object, through which an incompressible fluid/coolant which causes cooling of the object flows circulating during operation. When the temperature level changes, the fluid is subject to a change in volume in relation to a certain pressure, i.e. at atmospheric pressure, for example. If there is no space available for the volume change, the fluid reacts with a pressure change in the cooling circuit. This applies in particular to incompressible fluids.

From the DE 10 2017 001 447 A1 an expansion tank for a coolant circuit of an internal combustion engine of a motor vehicle is known, with an expansion opening through which coolant of the coolant circuit can flow into and out of an interior space of the expansion tank, with a membrane being arranged in the interior space of the expansion tank, which divides the interior space into a fluidic the compensating opening connected compensating volume and divided into a separate from this bias volume, which can be filled with a medium via a filling opening of the equalizing tank.

The object of the present invention is to propose improvements in relation to a cooling arrangement.

The object is achieved by a cooling arrangement according to patent claim 1. Preferred or advantageous embodiments of the invention and other categories of the invention result from the further claims, the following description and the attached figures.

The cooling arrangement serves or is set up to cool an object. In particular, the cooling arrangement serves or is set up to set a predefinable pressure in a fluid during operation, which circulates in a cooling circuit of the cooling arrangement.

The cooling arrangement includes a cooling circuit. This serves or is set up to cool the object. When the cooling arrangement is operated as intended, an incompressible fluid that causes the cooling of the object flows circulating through the cooling circuit. In other words, the fluid circulates through or along the cooling circuit, absorbing heat from the object and releasing it to another point in the cooling circuit, e.g. to a cooler. For this purpose, the cooling circuit is equipped in particular with a feed pump for the fluid. The volume of fluid in the cooling circuit varies. This is because the fluid undergoes thermal expansion as the temperature changes. The temperature expansion of the fluid discussed here affects it as a whole. What is meant here is not the temperature fluctuations of the fluid during circulation in the cooling circuit, but the change in the temperature level in the cooling circuit as a whole.

The "volume" of the fluid refers to the volume that the fluid would assume without external force, i.e. e.g. at atmospheric pressure, if it was at the appropriate temperature. In fact, however, only its (constant) volume / total volume is available to the fluid in the cooling circuit. A "volume increase" mentioned above could therefore not take place in the cooling circuit (under constraint of the given volume of the cooling circuit). Instead, the fluid - precisely because of its incompressibility - would react with a strong increase in pressure in the cooling circuit. A compensating volume (fluid space) in the form of a compensating tank is therefore provided on the cooling circuit in order to derive the additional fluid volume from the cooling circuit and thus avoid the forced increase in pressure. When the volume decreases, fluid is brought back into the cooling circuit from the fluid space.

"Incompressible" is to be understood here in the sense of the usual incompressibility of liquids such as water or oil. In fact, these liquids are compressible to a certain extent, but react with a - compared to e.g. gases such as air or nitrogen - with a significantly greater increase in pressure in a closed volume under otherwise identical conditions (volume, temperature change, ...).

The cooling arrangement also contains the fluid.

The cooling arrangement also contains a surge tank (also referred to as "surge tank") mentioned above. The expansion tank contains a fluid space (compensation volume). This is “connected” to the cooling circuit, i.e. it is fluidically connected to it via an equalization opening or equalization line. Fluid can therefore flow back and forth between the cooling circuit and the fluid space via the equalizing opening/line. During operation of the cooling arrangement, the fluid space is at least partially--in particular completely, i.e. exclusively/without a gas or air space--filled with the fluid.

Strictly speaking, “compensation” or “pressure compensation” means the following: the expansion tank is actually more of a volume expansion tank than a pressure expansion tank ter. Because if the volume of the fluid changes due to a change in temperature, excess fluid/volume (which no longer "fits" in the cooling circuit at the same or similar fluid pressure) escapes into the expansion tank or fluid space, or fluid from the expansion tank flows back into the cooling circuit to fill the latter to be filled with more fluid if the volume of the fluid decreases. In other words, more or less (partial) volume of the fluid is "outsourced" from the cooling circuit to the fluid space.

The expansion tank has a rigid first wall section. This includes, in particular, an inlet opening into the fluid space, through which the above-explained volume exchange/compensation of fluid between the cooling circuit and the fluid space takes place. The inlet opening is therefore the equalization opening or the end of the equalization line connected to the cooling circuit.

Alternatively or additionally, such an inlet opening is provided in a second wall section. The expansion tank has the second wall section. The first and second wall section together (or at least one respective section of the first and second wall section) delimit the fluid space, ie completely form its wall. In addition to (at least parts of) the first and second wall section, the wall of the fluid space therefore contains no further parts.

At least part of the second wall section forms a movement area of the expansion tank. The range of movement can also be identical to the second wall section. The movement portion is moveable relative to the first wall portion to vary the volume of the fluid space. "Movable" is to be understood here in particular in the sense of "actively changeable", i.e. controllable / adjustable / specifiable. This represents a distinction, e.g. from the - in this sense "passive" known membrane as the second wall section / area of movement in an expansion tank. Because such a membrane is passively changed, deformed, shifted, stretched by the pressure of the fluid and reacts at most with a counter-tensioning force on the change in volume of the fluid in the expansion tank (usually compression of gas beyond the diaphragm). In the present case, however, the shape/position of the second wall section/movement area is in particular actually actively specified/set under external pressure, e.g. by an actuator, i.e. the volume of the fluid space is firmly specified or set. The fluid then reacts to this (at its volume, which depends on the temperature level) with a certain pressure in the cooling circuit/fluid space.

The corresponding volume adjustment allows the inflow / outflow of fluid into or out of the fluid space and the adjustment of the pressure of the fluid (in the cooling circuit and also in the fluid space). The decisive factor for the fluid pressure is only the actual volume of the fluid that it would occupy at atmospheric pressure and the cavity actually available for the fluid volume that it can fill. In other words, the volume adjustment of the fluid space allows the pressure in the fluid to be influenced. In this respect it is possible according to the invention to adjust or control the pressure of the fluid without having to expose the fluid to contact with oxygen for this purpose.

• In einer Variante A) ist der zweite Wandabschnitt insgesamt als Bewegungsbereich ausgeführt. Der zweite Wandabschnitt ist dann - wie der erste Wandabschnitt - ebenfalls starr ausgeführt und in seiner Gänze relativ zum ersten Wandabschnitt beweglich ausgeführt. Insbesondere ist dabei der zweite Wandabschnitt nach Art eines Kolbens im ersten Wandabschnitt nach Art eines Zylinders verschiebbar geführt, wobei der Kolben-/Zylinder-Vergleich nur für den Bewegungsbereich des zweiten Wandabschnitts im ersten Wandabschnitt gelten muss, ansonsten können die Wandabschnitte beliebig geformt sein.

Two variants are now possible for the second wall section, which can occur alternatively or together:

• In a variant A), the second wall section is designed overall as a movement area. The second wall section is then—like the first wall section—also designed to be rigid and to be movable in its entirety relative to the first wall section. In particular, the second wall section is slidably guided in the manner of a piston in the first wall section in the manner of a cylinder, with the piston/cylinder comparison only having to apply to the range of motion of the second wall section in the first wall section, otherwise the wall sections can be of any shape.

In a variant B), the shape of the movement area of the second wall section can be changed. “Gestalt” here means a form/position. “Changeable” is therefore to be understood as meaning a deformation/bending/change in position of the movement area relative to the first wall section. In this respect, the position of individual locations/sections of the movement area relative to one another and/or to the first wall section or to a (fixed) part/section of the second wall section that does not belong to the movement area can be changed. In this sense, the movement area is designed to be movable relative to the first wall section.
The second wall section thus forms a “separator” in the expansion tank, which separates the fluid space from the rest of the space (working volume, eg gas space/air space) of the expansion tank. The working volume is in connection with the surroundings of the expansion tank and shows its pressure level.

The variants A and/or B presented according to the invention open up many possibilities of pressure/volume balancing in a cooling arrangement.

In a preferred embodiment, the cooling arrangement contains at least one actuator. This is set up for active adjustment of the range of motion. The actuator thus causes the active compulsory specification of the movement/shape/position of the movement area, in particular of the entire second wall section relative to the first wall section. Thus, the volume of the fluid space is forcibly adjusted/specified by actuators. The pressure of the fluid can thus be adjusted via the given volume of the fluid at a specific temperature level. The actuator is designed in particular as a direct drive for the range of motion, in particular a linear drive. Alternatively, however, a lever mechanism, a gear, a scissors joint, etc., can cause a movement coupling between the actuator and the movement area.

In particular, the cooling arrangement contains at least one pressure sensor for detecting a current pressure/pressure level of the fluid at a specific point/area of the cooling circuit/fluid space. The actuator can then be operated as a function of pressure-correlated data recorded by the sensor.

In particular, a specific pressure in the fluid can be adjusted (controlled or regulated) in this way. In particular, the cooling arrangement also contains a controller for the actuator in order to cause/adjust a specific movement/position of the movement area. In particular, the control takes place on the basis of a pressure-correlated variable provided by the pressure sensor. In particular, the pressure value of the fluid can thus be kept between a lower and an upper threshold value, for example by regulation.

In a preferred variant of the above embodiment, the actuator is an electric and/or hydraulic and/or pneumatic drive. This results in a variety of options for manipulating the range of motion.

In a preferred embodiment, the cooling arrangement contains at least one compressible buffer element, which is arranged in the fluid space. A corresponding buffer element also serves to equalize the pressure/volume of the fluid in the fluid space/cooling circuit. A corresponding buffer element acts like the passive membrane explained above. In this sense, the buffer element contains or forms the above-mentioned pretensioning volume. Here, "compressible" is related to "incompressible" and means that the buffer element is significantly more compressible than the fluid. Thus, in particular smaller volume/pressure fluctuations in the fluid can be absorbed by the buffer element without having to move the movement area for this purpose. In particular, the above-mentioned actuator can be protected in this way, in that it is relieved of correspondingly small corrective movements of the movement area and the pressure in the fluid nevertheless remains within the desired limits.

In particular, the fluid space (together with the cooling circuit, an equalizing line, etc.) contains only the fluid and the buffer element and no other elements. As a result, there are precisely known conditions in the cooling circuit / fluid space.

In a preferred variant of this embodiment, the buffer element is a compressible loose gas or a compressible elastic object. The loose gas is present in particular as a gas bubble in the fluid space, ie as a gas space or gas volume, ie a gas-filled partial space of the fluid space in which no fluid is present. "Elastic" is to be understood here in the sense of compressible but "solid / not gaseous".

However, the object can in particular be gas-filled, for example, in which case the compressibility/elasticity is then essentially achieved by the gas/the gas filling. In particular, the object is a gas-filled stretchable cushion or a foam body made of closed-cell foam. The individual closed foam cells then roughly correspond to a large number of gas-filled elastic bodies/partial objects.

In a preferred embodiment, the cooling arrangement includes at least one spring element that resiliently biases the second wall portion or the range of motion in relation to compression of the fluid space (a smaller, decreasing volume of the fluid space). Thus, for example, no actuator is necessary in order to move the second wall section in variant A) or the movement area in variant B) in relation to a compression/in the direction of smaller volumes of the fluid space. The spring element thus effects in particular a certain minimum pressure in the fluid. In particular, however, the spring element is combined with an actuator, so that the actuator is supported by the spring element. In particular, the spring element has a linear spring characteristic. In particular, the spring element has a degressive spring characteristic in the direction of a larger volume of the fluid space. This enables a larger spring stroke (and thus more freedom of movement of the movement area and thus volume compensation in the fluid space) with the same spring forces in comparison to a linear spring characteristic.

In a preferred variant of the above-mentioned embodiment with an actuator, the second wall section is designed according to variant A) and the actuator is a linear drive for displacing the second wall section in the first wall section. In particular, the wall sections form the "piston in cylinder" configuration discussed above. A particularly simple, motor-driven, active adjustment/adjustment of the size of the fluid space, in particular of the piston in the cylinder, is thus achieved. In particular, this embodiment can also be combined with the spring element mentioned above. Depending on the design of the spring force in relation to the necessary hold-down forces of the second wall section, it may be necessary for the actuator to exert tensile forces alone or compressive forces alone or also tensile and compressive forces on the second wall section. In this way, a correspondingly large number of variants of actuator configurations can be found.

In a preferred embodiment, the second wall section is designed according to variant B) and the expansion tank has a rigid housing. At least part of the housing forms the first wall section. An expansion element is arranged in the interior of the housing or the expansion tank. At least part of the surface of the expansion element forms the second wall section, in particular the movement area. The volume of the expander is variable to change the shape of the range of motion of the second wall section. In this way, particularly varied embodiments of the cooling arrangement can be designed as required. The expansion element is therefore located—in particular completely—in the expansion tank and delimits (together with the first wall section) the fluid space. The fluid is outside of the expansion element.

In a preferred variant of this embodiment, the expansion element is a bellows whose shape and/or length can be changed. A change in shape and/or length results in a change in volume of the bellows or expansion element. In particular, the bellows can only be changed one-dimensionally in a direction of longitudinal extent, i.e. it does not undergo a bending movement, but only an expansion or compression movement in order to bring about a change in volume. This results in a particularly simple solution for an expansion element.

In a preferred embodiment, the second wall section is designed according to variant B). At least a part of the expansion tank and thus of the fluid space is itself designed as an expansion element. So here fluid is - contrary to above - within expansion element. The first wall section is at least partially formed by an inlet area of the expansion tank, possibly the expansion element. The inlet area is that which has an inlet opening for the fluid for connection to the cooling circuit. At least part of the movement area is formed by a deformable area of the expansion element. This also leads to an alternative solution for an expansion tank.

In a preferred variant of this embodiment, the expansion element is also a bellows that can be changed in terms of its shape and/or length. The area of movement or at least the above-mentioned part of the area of movement is then formed by at least part of a bellows area of the bellows. The statements made above for the bellows (the fluid is outside of it) apply here as well.

In a preferred variant of this embodiment with the above-mentioned actuator, the second wall section is at least partially also formed by at least part of an area where the actuator acts on the bellows. The attack area is used so that the actuator can actively change the shape and/or length of the bellows. The actuator is therefore used or is set up to manipulate the shape/length of the bellows, in particular to stretch or compress it exclusively linearly. Then the actuator is in particular a linear drive. Since the attack area is also moved as a result of the actuator movement, this is particularly suitable as part of the second wall section, in particular part of the movement area.

The object of the invention is also achieved by an object arrangement according to claim 13. This contains the cooling arrangement according to the invention and the object.

The object arrangement and at least some of its possible embodiments and the respective advantages have already been explained in connection with the cooling arrangement according to the invention.

In a preferred embodiment, the object is a fuel cell assembly. This contains at least one fuel cell to be cooled by the cooling arrangement. The fuel cell is in particular one in an electrically powered aircraft and/or in an aircraft in which a power supply system of the aircraft is fed permanently or temporarily by the electrical energy obtained from the fuel cells. In other words, it could alternatively or additionally also be a fuel cell that (only) is used for power or emergency power supply (and if not the engine(s) of the aircraft is used. "Powered" is understood to refer to the aircraft's main engine for flight. So the aircraft is not driven by internal combustion engines / turbines / engines, but by electric motors, eg with propellers. The electrical energy for the electric motors and thus the flight / propulsion of the aircraft is generated by the fuel cells. The electrically powered aircraft thus contains a fuel cell arrangement with fuel cells, which in turn are cooled by the cooling arrangement. In this application in particular, the cooling system according to the invention is particularly advantageous because of its pressure control/regulation properties.

The object of the invention is also achieved by an aircraft according to patent claim 15. This contains the object arrangement described above with the fuel cell arrangement as the object. As described above, the aircraft is or will be driven in flight by the electrical energy obtained from the fuel cells and/or a power grid of the aircraft is or will be permanently or temporarily fed by the electrical energy obtained from the fuel cells.

The aircraft and at least some of its possible embodiments and the respective advantages have already been explained in connection with the object arrangement according to the invention and the cooling arrangement according to the invention.

The invention is based on the following findings, observations and considerations and also has the following embodiments. The embodiments are sometimes also referred to as “the invention” for the sake of simplicity. The embodiments can also contain parts or combinations of the above-mentioned embodiments or correspond to them and/or optionally also include embodiments that have not been mentioned before.

The invention is based on the idea of developing a compensating tank with, in particular, active regulation of the fluid volume while excluding contact of the fluid with oxygen in a compact and space-saving design.

The invention is based on the observation that it is known from practice or the state of the art to use an expansion tank with a gas space (preload volume/membrane/equalization volume, passive): In general, passive expansion tanks are used in fluid circuits to compensate for the heat / Volume expansion of the fluids used. Here, a gas bubble (preload volume) is compressed when the liquid expands. Only with a sufficiently large gas space (preload volume) does a flat increase in pressure occur.

The invention is based on the following idea: In order to keep the system pressure (pressure in the fluid) constant or set it to a desired value, the expansion tank is designed in particular as a cylinder with a piston/bellows. “Below” the piston (on the side of the piston facing the fluid space) is the fluid and optionally a small gas space (buffer element). When the fluid expands, the increase in pressure (in the cooling circuit / fluid space) is optionally detected by sensors and the piston / bellows is released by an external force (e.g. linear drive (actuator) etc. and / or spring force) directly or by means of a lever mechanism (between the actuator and the second Wall section / range of motion) pulled out and thus the available volume (of the fluid space) increased. This counteracts the pressure increase in the cooling circuit/fluid space caused by the expansion of the fluid, in order to keep the pressure below a maximum pressure, for example. A small gas space (buffer element, possibly as a closed balloon) is used to buffer pressure surges and enables fine control. When it cools down, the system pressure (pressure in the fluid) drops, which is also recorded by the sensors and the piston / bellows is pressed inwards (towards the fluid space) to reduce the volume (of the fluid space) again. This causes an increase in pressure (in the fluid) that compensates for the drop in pressure due to the cooling (decrease in volume of the fluid) in order, for example, to maintain a minimum pressure in the fluid.

This type of pressure control/regulation means that the expansion tank can be made significantly smaller than in the case of the passive gas bubble (preload volume) known from the prior art, since this is simply not required. This requires significant savings in terms of weight (no encasing of the prestressed volume) and installation space (no prestressed volume) in aircraft. In addition, a finer pressure control and thus a smaller total system pressure (in particular less fluctuation of the pressure in the fluid) are possible.

The combination of a small gas space (buffer element) for buffering pressure peaks with the motorized change in volume (actuator) means that very small expansion tanks can be used, which at the same time allow very fine pressure control.

According to the invention, this results in a particularly actively controlled expansion tank, which by means of mechanical adjustment (actuator/spring element) of a separating device (second wall deflector section / range of motion) controls / regulates the desired pressure (in the fluid). At the same time, contact of the fluid with oxygen is avoided.

• 1 ein Flugzeug mit einer Brennstoffzelle, die von einer Kühlanordnung gekühlt wird,
• 2 einen zu 1 alternativen Ausgleichsbehälter mit enthaltenem Dehnelement außerhalb des Fluids,
• 3 einen zu 1 alternativen Ausgleichsbehälter mit fluidgefülltem Dehnelement,
• 4 einen zu 1 alternativen Ausgleichsbehälter mit Federelement,
• 5 einen zu 1 alternativen Ausgleichsbehälter mit verlängertem Federelement,
• 6 unterschiedliche Federkennlinien für die Federelemente aus 4 und 5.

Further features, effects and advantages of the invention result from the following description of a preferred exemplary embodiment of the invention and the attached figures. Show, each in a schematic principle sketch:

• 1 an aircraft with a fuel cell cooled by a cooling arrangement,
• 2 one to 1 alternative reservoir with included expansion element outside the fluid,
• 3 one to 1 alternative expansion tank with fluid-filled expansion element,
• 4 one to 1 alternative reservoir with spring element,
• 5 one to 1 alternative reservoir with extended spring element,
• 6 different spring characteristics for the spring elements 4 and 5 .

1 shows a detail of an aircraft 2, not shown. This has an electric drive, not shown, so it is powered by electric energy instead of fossil fuels for flying. The electrical energy is obtained from an object 4 in the form of a fuel cell arrangement which essentially contains a plurality of fuel cells. In the 1 only one of the fuel cells is shown as representative of the object 4 . During operation, the fuel cells have to be cooled.

The aircraft 2 therefore contains an object arrangement 6; This includes the object 4 and a cooling arrangement 8 for cooling the object 4, here the fuel cell shown. The cooling arrangement 8 is therefore used to cool the object 4.

The cooling arrangement 8 contains a cooling circuit 10 for the actual cooling of the object 4. During operation, the cooling circuit 10 is filled with an incompressible fluid 12 (medium, in 1 hatched) flows through what is in 1 is represented by an arrow 14 indicating the circulation of the flow. The fluid 12 is part of the cooling arrangement 8. The fluid 12 causes the actual cooling of the object 4 in that it absorbs heat from it as it flows past and releases it again within the cooling circuit 10—at a cooler, not shown. A pump 15 in the cooling circuit 10 serves to maintain the circulatory flow of the fluid 12 in the direction of the arrow 14.

Due to changes in the overall temperature level of the fluid 12, it expands when heated and contracts when cooled, i.e., the volume VF of the fluid 12 varies. The volume VF of the fluid 12 refers to the volume that the fluid 12 would assume without being forced, i.e. at atmospheric pressure, for example. In fact, however, only the total volume of the cooling circuit 10 (this is always assumed to be constant in the present case) plus the volume VR of the fluid chamber 20 is available for the fluid 12 . The expansion (“desired” by the fluid) leads (if this cannot take place) to a pressure increase of the pressure p of the fluid 12 in the cooling circuit 10 and fluid space 12 (if this has a constant volume VR).

In order to compensate for this change in volume in the fluid 12 , a compensating tank 16 is connected to the cooling circuit 10 . The "connection" is symbolically represented here by an equalizing line 18 . Alternatively, however, the expansion tank 16 can also be connected directly to the cooling circuit. The expansion tank 16 has a fluid space 20 which is completely filled here and has a total volume VR. A part of the filling consists of the fluid 12, the remaining part of the filling consists of a compressible buffer element 22. The buffer element 22 is here a compressible elastic object 26, here an elastic bladder filled with gas. The buffer element 22 is also part of the cooling arrangement 8. In the present case, the fluid chamber 20 is only partially filled with the fluid 12.

The expansion tank 16 has a first rigid wall section 28a, which is designed here in the manner of a pot-shaped cylinder with a bottom. The reservoir 16 also has a second wall portion 28b, here also rigid, which here, according to variant A) of the invention, is made in the manner of a piston capable of sliding linearly in the cylinder with a single degree of freedom. Here, the second wall section 28b is rigid overall and is designed to be movable relative to the first wall section 28a. The exclusively linear one-dimensional mobility is in the 1 indicated by a double arrow 32. The entire second wall section 28b therefore forms a movement area 34 of the expansion tank 16.

First wall section 28a (its lower part reaching to the piston) and second wall section 28b together delimit fluid chamber 20. Fluid chamber 20 is therefore completely delimited solely by wall sections 28a and 28b. The mobility of the movement area 34 in the direction of the double arrow 32 means that the volume VR of the fluid chamber 20 can be changed.

If the volume VF (if it can expand unhindered) of the fluid 12 in the cooling circuit 10 increases due to an increase in temperature (total temperature level of all parts of the fluid 12), an additional volume proportion of the fluid that is created in this way escapes via the equalizing line 18 into the equalizing tank 16 or the fluid chamber 20 from. By actively sliding the second wall section 28b (in 1 upwards), the volume VR of the fluid space 20 is increased to a corresponding extent, so that the additional volume (the more volume VF) of the fluid 12 finds space. When the temperature decreases and the volume in the fluid 12 decreases, a corresponding quantity of fluid flows back from the fluid chamber 20 through the equalizing line 18 into the cooling circuit 10; the second wall section 28b becomes active in 1 moves down and the volume VR of the fluid chamber 20 is reduced accordingly.

In order to bring about the corresponding movement of the second wall section 28b, the cooling arrangement 8 contains an actuator 36, here an electric drive in the form of a linear motor which has an output element 38 which can be moved linearly in the direction of the double arrow 40. The actuator 36 or the output element 38 is connected directly to the second wall section 28b, ie without the interposition of a lever mechanism or any other transmission arrangement. The actuator 36 is thus set up as an actuation unit (electromechanical linear drive) for the active adjustment of the movement range 34 .

The total volume available for the fluid 12 in the cooling arrangement 8 (including the cooling circuit 10) is also changed by the actuator-controlled adjustment (actuator 36) of the movement area 34/second wall section 28b and thus of the volume VR of the fluid chamber 20. In relation to the volume that the fluid 12 wants to take up due to its temperature properties (in the unpressurized state) (fluid volume VF), and which is actually available for the fluid 12 (here consideration of the fluid space volume VR, since only this can be changed) this results a pressure p in the fluid 12. By setting the volume VR, which is thus made available for the fluid 12, the pressure p in the fluid 12 can be set. In particular, this can thus be kept in a range between a minimum pressure pmin and a maximum pressure pmax (in 1 represented symbolically).

Total shows 1 thus an embodiment of the invention in which the second wall section 28b is designed according to variant A) and the actuator 36 is a linear drive for its displacement in the first wall section 28a.

The rigid wall section 28a is here part of a rigid housing 42 of the expansion tank 16. In order to enable the movement of the second wall section, the expansion tank 16 or the housing 42 has a space in the form of a working volume 68 that is located opposite the fluid space 20 Side of the second wall portion 28b is located. The housing 42 or the expansion tank 16 contains an inlet area 52. This in turn contains an inlet opening 54 for the fluid 12 to flow into/out of the expansion tank 16. The inlet opening 54 is therefore used to connect the expansion tank to the expansion line 18 or via this to the cooling circuit 10.

1 thus shows an active pressure regulation on the expansion tank 16 or a separating device/separating piston in the form of the second wall section 28b.

2 shows an alternative embodiment of an expansion tank 16. As in FIG 1 this has a housing 42, an inlet area 52 with an inlet opening 56, a rigid first wall section 28a and an actuator 36. An expansion element 44 is arranged in the interior of the housing 42 . A part of the surface 46 of the stretching element 44 here forms the second wall section 28b and also the movement area 34. The volume VD of the stretching element 44 is variable. With the corresponding change, the shape of the movement area 34 changes.

The expansion element 44 is designed here as a bellows 48, the shape and length of which can be changed. In the present case, the bellows can be stretched or compressed linearly along its direction of longitudinal extension 49 . The change in length is again indicated by an arrow 32 . The actuator 36 is corresponding 1 embodied, except that this engages here with its driven element 38 on a working area 50 of the bellows 48 in order to stretch or compress the bellows 48 in the direction of the double arrow 32 in order to change its volume VD. In the embodiment shown here, a buffer element 22 arranged in the fluid space 20 is a compressible, loose gas 24 which floats on top of the fluid in the form of a gas bubble or surrounds the bellows 48 .

2 thus shows in contrast to 1 a variant B) of the invention, according to which a shape of the movement area 34 of the second wall section 28b can be changed. In the present case, this occurs in that the (foldable) bellows area 56 changes as a movement area 34 when the bellows 48 is stretched or compressed in the direction of the double arrow 32 . The attack area 50 as part of the second wall section 28b, however, is displaceable in position relative to the first wall portion but does not change shape.

Also 2 thus shows an active pressure control on the expansion tank 16, here with the help of a bellows 48. Here - corresponding to the piston in 1 - The bellows 48, the separating device to separate the fluid space from the rest of the interior (working volume 68, interior of the bellows 48) of the housing 42.

3 shows a further alternative embodiment of a compensating tank 16. A part of this is itself designed as an expansion element 44, here specifically as a bellows 48 again. The bellows 48 is therefore in contrast to 2 filled here with the fluid 12 and with the buffer element 22 . Drive 36, engagement area 50, linear mobility of the bellows 48 (double arrow 32) etc. are designed in the same way as above with the difference that here the output element 38 acts on the bellows 48 on the outside and not on the inside.

The first wall section 28a is formed here exclusively by the inlet area 52 of the equalizing tank 16, which again contains the inlet opening 54 for the fluid 12 into the equalizing tank 16. The inlet opening 54 is therefore used for connection to the cooling circuit 10 or the compensating line 18. The working volume 68 surrounds the bellows 48 within the housing 42.

Here, too, the second wall section 28b is designed according to variant B) of the invention. As in FIG. 2, the movement area 34 is formed by a deformable area of the expansion element 44 . As above, this deformable area is the bellows area 56 of the bellows 48. Another part of the second wall section 28b (outside the variable-shape movement area 34) is also formed here, as above, by the engagement area 50 of the bellows 48 for the actuator 36 or its driven element 38. Here, too, the actuator 36 is used to change the shape or length of the bellows 48 or of its bellows area 56 . This is done again by stretching and compressing along the direction of longitudinal extent 49 of the bellows 48.

Also 3 thus shows an active pressure control on the expansion tank 16 with the help of a bellows 48. Here, too, the bellows 48 acts as a separating device between the fluid space 20 and the working volume 68.

4 shows a further alternative embodiment of a compensating tank 16. This essentially corresponds to the embodiment according to FIG 1 with the difference that no actuator 36 is provided here. Instead, the cooling arrangement 8 contains a spring element 60, here a helical spring, which is supported between the housing 42 of the expansion tank 16 and the second wall section 28b/piston. The spring element 60 therefore tensions the movable second wall section 28b, which here again corresponds entirely to the movement area 34, in relation to a compression of the fluid chamber 20, i.e. in the direction of a smaller/decreasing volume VR of the fluid chamber 20 (indicated by the arrow 62 ) before, so seeks to reduce the fluid space 20. An optional guide 64 in the form of a guide rod is attached to the second wall section 28b and slidably guided (double arrow 32) in the housing 42 in order to correspondingly guide the entire second wall section 28b straight/linearly in the first wall section 28a.

4 thus shows a passive pressure control on the equalizing tank 16/separating piston (separating device, second wall section 28b). The admission pressure or pressure p in the medium (fluid 12) is thus applied here via a spring (spring element 60) and not--as is known from the prior art--via a closed pretensioning volume. Instead of such a (tight, pressurized) prestressing volume, the working volume 68 (communicating with the outside, unpressurized/under atmospheric/ambient pressure) is present here again.

5 shows a variant of the embodiment 4 , which is designed to save space or volume. A (upper in the figure) spring chamber 66 of the working volume 68 / interior of the housing 42 is designed with a smaller diameter than a remaining (lower in the figure) working volume 68. Only the remaining working volume 68 offers space for moving the second wall section 28b / deforming the range of motion 34). The larger the cross-sectional area of the piston (transverse to the direction of movement of the double arrow 32), i.e. the second wall section 28b, is selected, the lower the maximum spring force F of the compression spring in the form of the spring element 60, and the lower the spring length L. Overall, this results in a flatter spring curve .

5 thus also shows a passive pressure regulation on the expansion tank 16/separating piston (separating device, second wall section 28b) as in FIG 4 .

6 shows spring characteristics 70a,b for different spring elements 60. The spring force F is plotted against the spring deflection s. The spring characteristic 70a is a linear spring characteristic, the spring characteristic 70b is a degressive spring characteristic. The spring force F1 results from the minimum required required hydraulic admission pressure in the cooling circuit 10, i.e. minimum pressure pmin of the coolant in the form of the fluid 12. The spring force F2 results from the maximum permissible pressure pmax of the coolant (Fluid12) in the cooling circuit 10. A corresponding functionality can be achieved with a spring element 60 with the spring characteristic 70a be reached. This results in a spring stroke s1. A degressive spring characteristic 70b can be advantageous because it enables a larger spring stroke s2 (corresponding to volume compensation in the fluid chamber 20) without exceeding the maximum spring force F2 and thus the maximum pressure pmax in the liquid circuit, i.e. cooling circuit 10 of the fluid 12, or the minimum spring force F1 and so that the minimum pressure pmin is not reached.

Reference List

2

Airplane

4

object

6

object arrangement

8th

cooling arrangement

10

cooling circuit

12

Fluid

14

Arrow

15

pump

16

surge tank

18

compensation line

20

fluid space

22

buffer element

24

gas (loose)

26

Object

28a

first wall section

28b

second wall section

32

double arrow

34

range of motion

36

actuator

38

output element

40

double arrow

42

Housing

44

stretching element

46

surface

48

bellows

49

longitudinal direction

50

attack range

52

entry area

54

intake port

56

bellows area

60

spring element

62

Arrow

64

guide

66

spring room

68

volume of work

70

innerspring line

VR

volume (fluid space)

vd

Volume (expansion element)

vf

volume (fluid)

p

Print

pmin

minimal pressure

pmax

maximum pressure

f

spring force

s

travel

L

spring length

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102017001447 A1 [0002]

Claims (15)

Cooling arrangement (8) for cooling an object (4), - with a cooling circuit (10) for cooling the object (4), through which an incompressible fluid (12) which causes cooling of the object (4) flows circulating and whose volume varies, - with the fluid (12), - with an expansion tank (16) which has a fluid space (20) connected to the cooling circuit (10) and at least partially filled with the fluid (12) during operation, - wherein the expansion tank (16) has a rigid first wall section (28a) and a second wall section (28b), the first (28a) and second wall section (28b) together delimiting the fluid space (20), at least part of the second wall section ( 28b) as a movement area (34) of the expansion tank (16) relative to the first wall section (28a) is movable in order to change the volume (VR) of the fluid space (20), wherein - A) the second wall section (28b) as a whole as a movement area (34) is also designed to be rigid and movable relative to the first wall section (28a), and/or - B) a shape of the movement range of the second wall section is changeable. Cooling arrangement (8) after claim 1 , characterized in that the cooling arrangement (8) contains at least one actuator (36) which is set up for the active adjustment of the movement range (34). Cooling arrangement (8) after claim 2 , characterized in that the actuator (36) is an electric and/or hydraulic and/or pneumatic drive. Cooling arrangement (8) according to one of the preceding claims, characterized in that the cooling arrangement (8) contains at least one compressible buffer element (22) which is arranged in the fluid space (20). Cooling arrangement (8) after claim 4 , characterized in that the buffer element (22) is a compressible loose gas (24) or a compressible elastic object (26). Cooling arrangement (8) according to one of the preceding claims, characterized in that the cooling arrangement (8) contains at least one spring element (60) which resiliently prestresses the second wall section (28b) or the movement area (34) in relation to a compression of the fluid space . Cooling arrangement (8) according to one of claims 2 until 6 , characterized in that the second wall section (28b) is designed according to variant A) and the actuator (36) is a linear drive for its displacement in the first wall section (28a). Cooling arrangement (8) according to one of the preceding claims, characterized in that the second wall section (28b) is designed according to variant B) and the expansion tank (16) has a rigid housing (42), at least part of the housing (42) having the forms the first wall section (28a), and an expansion element (44) is arranged in the interior of the housing (42), at least part of the surface (46) of the expansion element (44) forming the second wall section (28b), and the volume ( VD) of the stretching element (44) is variable in order to change the shape of the range of motion (34). Cooling arrangement (8) after claim 8 , characterized in that the expansion element (44) is a bellows (48) whose shape and/or length can be changed. Cooling arrangement (8) according to one of the preceding claims, characterized in that the second wall section (28b) is designed according to variant B) and at least part of the expansion tank (16) itself is designed as an expansion element (44), the first wall section (28a ) is formed at least partially by an inlet area (52) of the expansion element (44), which has an inlet opening (54) for the fluid (12) for connection to the cooling circuit (10), and at least part of the movement area (34) through a deformable area of the expansion element (44) is formed. Cooling arrangement (8) after claim 10 , characterized in that the expansion element (44) is a bellows (48) whose shape and/or length can be changed and the movement area (34) or a part thereof is formed by at least part of a bellows area (56) of the bellows (48). . Cooling arrangement (8) after claim 11 combined with claim 2 , characterized in that the second wall section (28b) is at least partially formed by at least a part of an engagement area (50) of the actuator (36) on the bellows (48) to change the shape and / or length. Object arrangement (6), with the cooling arrangement (8) according to one of the preceding claims and with the object (4). Object arrangement (6) according to Claim 13 , characterized in that the object (4) is a fuel cell arrangement which contains at least one fuel cell to be cooled by the cooling arrangement (8). Aircraft (2), with the object arrangement (6) after Claim 14 , wherein the aircraft (2) is powered in flight by the electrical energy obtained from the fuel cells and / or a power grid of the aircraft is fed permanently or temporarily by the electrical energy obtained from the fuel cells.

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