Apparatus for degassing a liquid.

[0001] The invention relates to a device for degassing a liquid from a liquid-carrying heating or cooling circuit or a top-up feedline for heating or cooling circuit, as defined in the preamble of independent claim 1 and a method for degassing a liquid from a liquid-carrying is heating or cooling circuit or a top-up feedline for heating or cooling circuit, as it is defined in the preamble of independent claim 6.

[0002] It is inevitable that e.g. in heater nets, in sequence of leakages or the like, in addition to the actual heat transfer medium, e.g. the heating water, air or other gases (oxygen and nitrogen) also occur, as well as to unwanted noise fan which to circulatory disorders or even in the heating or cooling system and to corrosion damage can lead in the hot water heater.

[0003] Degassing liquids apparatus and method are used by primary purpose negative pressure degassing, in the liquid, in particular water or water mixtures, dissolved gases, in particular nitrogen, in the external environmental excrete, among other things, for circulatory disorders, as well as to prevent a corrosion of the lines of the system. Such degassing devices be used in heating or cooling systems for example.

[0004] The negative pressure degassing is based on the principle that the increased and solubility ability of gases in a liquid by dropping the pressure therefore with increasing pressure in the form of different large bubbles dissolved in the liquid gas is desorbed from the liquid delivering.

[0005] In European Patent Application No 0,652,406 A1 are a method and a device for venting a liquid from a described A liquid circulation system. In this method a certain amount of liquid is removed from the circulation system and via a feed line, which contains an alternately open and closed shut-off valve, a closed deaeration tank supplied. Agent a continuously running circulating pump generates a reduced pressure in the deaeration tank is when the isolating valve is closed, so that air dissolved in the liquid is released and rises into the upper part of the vent tank. Patterns are projected by opening of the shut-off valve the pressure in the deaeration tank is increased, the air released into the outside air via a discarded, and the liquid is sucked off and container bleed valve unit returned to the circulation system.

[0006] This degassing operation, however, has a small degassing efficiency on. degassing procedure In implementing this must therefore be used to achieve a sufficient degassing also large degassing means.

[0007] The underlying purpose of the invention is, a device for degassing a gas containing liquid, in particular for fluid conveyance Heating or cooling circuit, so that allowance is made that a degassing of liquids in a circuit the most efficient manner possible and the use of comparatively small construction means can be ensured. For the purposes of this invention comprises not only in the classical sense Heating circuit A a circuit with a boiler, but also a heating cyclessolar cycle or also other.

[0008] This problem is solved by the device according to the invention, as defined in the independent claim 1 is, and by the method, which is defined in the independent claim 6. Advantageous embodiment variant of the device according to the invention and of the method according to the invention emerge from the dependent claims.

[0009] The essence of the invention is hereinafter referred to as:An apparatus for degassing a liquid from a liquid-carrying heating or cooling circuit or a top-up feedline for heating or cooling circuit comprises a degassing means for removing gas from a liquid by alternating vacuum and positive pressure production. The Degassing device includes a degassing container, a supply line for supplying the liquid for degassing container, a discharge tube for discharging the liquid from the degassing vessel, which has a pump and drain line can be connected to the heating or cooling circuit, and a vapor relief value unit. The vapor relief value unit the resignation allows gas from the degassing vessel to the degassing unit, it prevents the flow of the liquid from the degassing container and the backflow of gas at reduced pressure in the degassing container. The apparatus also includes a hydrocyclone for generating a vortex flow of the liquid, which is to be degassed, on the one hand and, on the other hand, with a feed line with the degassing device wherein the hydrocyclone for supplying the liquid is connected. The feed line being connectable to the heating or cooling circuit or the top-up feedline. The vapor relief value unit makes it possible, in particular a separating gas atmospheric air.

[0010] The Generating reduced pressure by the fluid conveying pump. These passes thereby that the exhausting flow rate of the pump is greater than the supply flow rate to the device. By the difference in these volumetric flow rates a reduced pressure is produced.

[0011] The pump is especially adapted, to generate excess pressure and reduced pressure in the outlet in the inlet. The pump may in particular be a high pressure centrifugal pump, to liquids is suitable.

[0012] The apparatus is particularly suitable for degassing of water or of water mixtures, mixtures preferably of water and antifreeze, in particular based on glycol, in particular propylene glycol and/or ethylene glycol. Here (bubbles) in the fluid may also pre-existing gaseous proportions (e.g. at a saturated system) are separated efficiently.

[0013] The Hydrocyclone is by a cylindrical chamber, comprising a cyclone coat, formed, wherein a tangential inlet to a cylindrical space leads.

[0014] This tangential inlet can be arranged at the same end as the draining of the hydrocyclone, or but at the opposite end of the hydrocyclone, but preferably at the same end as the draining of the hydrocyclone.

[0015] in It has shown surprisingly that an improved degassing of gas containing liquids can be achieved, by a combination of a hydrocyclone is used with a degassing device. To this end the hydrocyclone has a such form on that the fluid due to the flow deflection in the inlet region and the related to degassing rotating current passes along helically, in the case where the tangential cyclone coat as vortex the entrance and the exit is at the same end of the hydrocyclone or, in the case of the hydrocyclone are located-to the upper cap where the tangential intake and outlet flows are located-for deriving situated at opposite ends of the hydrocyclone.

[0016] The used because of their density difference contained in the liquid gas bubbles combines Hydrocyclone in comparison with the liquid in the centrifugal field. The bubbles are enlarged in combining by fusion that is to say, the bubbles grow, and facilitate thereby the excretion in the subsequent degassing device.

[0017] in a further embodiment variant, before or after the pump is located in the discharge line, preferably after the pump, a controllable [...]. This shut-off element allows a control of the liquid removal from the degassing vessel.

[0018] In another design variant is located in front of the feed line 21 also a pressure reducer and/or a flow controller. This design variant allows, with a higher pressure in the fluid-carrying heating or [...] work.

[0019] In an advantageous design variant is arranged in the feed line a pressure reducing means for gas bubble production. This pressure reducing means is a cross-sectional reduction Prefers, particularly a diaphragm preferably or a nozzle.

[0020] This pressure reducing means is a device, which can generate a turbulent flow. For example, a cross-sectional reduction may be used, which an efficient degassing of the liquid from the liquid carrying heating or cooling circuit or the top-up feedline and therefore allows a use of smaller construction component. This efficient degassing takes place in the system by an additional, targeted gas bubble formation and accelerating the desorption of the gas from the liquid, due to the pressure reducing means before entry into the hydrocyclone. This gas bubble enlargement also accelerated the pressure reducing means. The create a turbulent flow within the liquid in the liquid leads to points of negative pressure, particularly where the gas bubble formation will be promoted. The use of a diaphragm or a nozzle shows particularly good properties at the gas bubble formation and gas bubble enlargement.

[0021] Preferably the feed line between the reduction, preferably between the shield or an angle of at least 60° on the nozzle and the hydrocyclone. 120° is ° to 70 the angle Preferably,.

[0022] This angle in the feed line after the cross-sectional reduction, of the diaphragm or of the nozzle allows a reduction in the volume of the device in operation surprisingly, in particular to the reduction of a sizzling noise in operation occurring.

[0023] In another variant the device has at least one expansion tank for pressure compensation, by receiving thermal expansion of the volume of expansion of the liquid at, on. The Expansion vessel comprises a bellows for receiving the liquid. The Expansion vessel is of a pressure-equalising line, which comprises a controllable shut-off member, with the degassing vessel or connected to the drain line.

[0024] This variant shows advantageously in the pressure compensation of the liquid from a liquid-carrying heating or cooling circuit. Changes in the temperature in the liquid carrying heating or cooling circuit lead to changes in volume of the recirculating liquid and thus to pressure changes in the circuit. Excessive leakages pressures can and for addressing said safety valves to damage in the system and to low pressures [...], air introduction and cavitation, cause. air introduction in turn can lead to malfunctions of the system by the and the nitrogen content is reduced and the oxygen content is noise fan to corrosion. These disadvantages are taken by the expansion tank, the supply via surplus volume and this increase in volume of the recirculating liquid in the circuit controls the send said pressure compensating valve the expansion chamber, where the liquid is effected under exclusion of air and atmospheric pressure is mounted, and the missing volume volume decrease of the recirculating liquid from the expansion tank in the circuit, in which case the feeding of the liquid from the expansion chamber before the pump. When supplying the missing volume from the expansion vessel a further Synergistic effect enters a of the device according to the invention, wherein the pump is used is stored for feeding the liquid from the expansion chamber has, against atmospheric pressure, back into the fluid-carrying heating or cooling circuit, which an increased pressure,.

[0025] a degassing container is connected with the pressure equalization line or with the low-temperature line preferably, the with the circuit via a controllable shutoff device and a heat exchanger or a temperature layer container connected.

[0026] This variant of the device allows, to apply the expansion vessel with a liquid, its temperature is less than the temperature of the liquid-conducting [...] -or cooling circuit. This embodiment permits the reliable use of a material for the bellows in the expansion chamber is suitable for only temperatures, which are less, than the temperature, the prevailing [...] -or cooling circuit in the liquid-conducting.

[0027] the invention is also a method for degassing a liquid from a liquid-carrying [...] -or cooling circuit based on, during the [...] or cooling circuit is taken from the liquid in a sucked degassing cycle, [...] into a degassing vessel and from the degassing vessel by a [...] -or cooling circuit is again forwarded to the. The pressure in the degassing container or in the device is reduced by controlling the liquid supply or the liquid removal in such a way that in the liquid and rises into the upper part of the degassing is freely dissolved gas. By subsequent controlling the liquid supply and/or the liquid removal is again increases the pressure in the degassing container. This is excreted via a gas in the top part of the degassing is vapor relief value unit from the degassing vessel.

[0028] The procedure is particularly suitable for degassing of water or of water mixtures, mixtures preferably of water and antifreeze, in particular based on glycol, in particular propylene glycol and/or ethylene glycol. The [...] -or cooling circuit is from 0.2-32 bar pressure within the fluid-carrying, 1 preferably -25 bar, in particular 1-10 bar.

[0029] This process control is that there needs to be better degassing of the liquid from the liquid carrying [...] -or refrigerating cycle or from the top-up feedline.

[0030] Preferably, being regulated by at least one pump and/or the liquid feed or the liquid removal at least a controllable shut-off member. Preferably is located in the outflow duct the shut-off member, in particular before or after the pump, preferably after the pump.

[0031] The controlling the liquid supply or the liquid removal is performed preferably through Fluid flow control of the pump by the pump, in particular by controlling the rotational speed of the pump.

[0032] Furthermore, preferably used for producing gas bubbles before Hydrocyclone a diaphragm or a nozzle.

[0033] This design variant is most efficiently in the degassing of the liquid from the liquid carrying heating or cooling circuit or the top-up feedline.

[0034] Preferably, determined by detecting the pressure by means of a control unit the gas concentration in the liquid between a check valve and an orifice or an overflow valve in the course of the pressure during the degassing cycles vapor relief value unit and evaluation of the by the control unit.

[0035] In another design variant, determined by means of a control unit the gas concentration in the liquid by detecting the amount of secreted gas flow meter in each degassing cycle by the control unit by means of a gas.

[0036] The abovementioned variants may also be carried out in combination with one another.

[0037] the device according to the invention is described in what follows, with reference to the accompanying drawings for degassing a liquid more detail with reference to embodiments. It show:

Fig. 1, a schematic representation of one embodiment of a device according to the invention; for degassing a liquid from a liquid-carrying heating or cooling circuit or the top-up feedline for heating or cooling circuit;

2 a schematic representation of a further embodiment a compound of the invention said-Fig.

tung for degassing a liquid from a liquid-carrying heating or cooling circuit or the top-up feedline for heating or cooling circuit with an expansion chamber for pressure compensation;

Fig. a schematic representation of a second embodiment of a device according to the invention; 3 for degassing a liquid from a liquid-carrying heating or cooling circuit or the top-up feedline for heating or cooling circuit with an expansion chamber for pressure compensation;

Fig. 4 a cross-sectional view of a hydrocyclone with a degassing container according to one embodiment of the invention;

Fig. 5 a cross-sectional view of a hydrocyclone with a degassing container in operation according to one embodiment of the invention;

Fig. 6, a perspective view of a compact mode of construction of an embodiment;

Fig. 7 a 90° angle in the feed line with a cross-sectional view of a diaphragm according to the cut-out is provided in 6 Fig. A;

Fig. 8 a perspective view of a further compact mode of construction of an embodiment with connections for an expansion vessel;

Fig. 8 9 a further perspective view of the compact mode of construction from Fig.;

[0038] the following definition applies for the entire further description. Reference numbers contained in a Figure for the purpose graphic clarity Are, but not explained in the directly associated textual description, reference is made to the information in preceding descriptions of figure so.

[0039] The 1 illustrated apparatus for degassing a liquid from a liquid-carrying in Fig. heating or cooling circuit or the top-up feedline for [...] -or cooling circuit has a degassing device 1 on, which a substantially cylindrical, closed degassing container comprises 11. Am degassing tank bottom 15 is mounted a liquid inlet 14. The liquid inlet 15 is connected via a feed line 12 with a 2 [...] -cyclone.

[0040] 21 by means of the feed line 2 is with the liquid carrying [...] The [...] -or cooling circuit connected, the top-up feedline [...] -or cooling system may be for example a or with the. The [...] is used, to generate a vortex with the liquid to be degassed to be expanded and increase all the more the gas bubbles, if any.

[0041] is 3 provided with a shutter 21 feed line The, which arises is used, to reduce such [...] hydration of the 2 that an increased pressure reduction and a turbulent flow on the diaphragm and so a bubble formation and blister enlargement improved. The Skirt is not obligatory, as mapped, [...] to be arranged outside the, but can be, for example, directly and tangentially into the open part of the [...][...].

[0042] also the feed line points between the aperture and the liquid carrying a flow restrictor 8 [...] -or cooling circuit or the top-up feedline 22, despite fluctuating pressure differences largely constant holds the the flow. The embodiment, also a further controllable shut-off element 23, a pressure reducer 24, a filter 25 (Mud flap), a pressure sensor 26 and 27 on a further shut-off element. The pressure reducer 24 allows, the method for degassing with a higher pressure above 3 bar absolute, preferably up to 25 bar absolute, in the liquid carrying [...] -or cooling circuit to perform reliably.

[0043] 14 or the side wall 18 of the degassing container 11 is furthermore degassing tank bottom The with a liquid outlet provided, through which the liquid flows into a discharge line 4. A pump 4 is located at the drain line 41, by means of the the liquid carrying [...] -or cooling circuit to degassing liquid is removed, through the diaphragm and the and from there into the degassing container from the liquid carrying [...][...] -or cooling circuit 11 sucked is supplied again. The discharge line between the pump 1 and the liquid carrying [...] -or 4 is cooling circuit 42 provided with a non-return valve, prevents the that liquid from the liquid carrying [...] -or cooling circuit interruptions or reductions of liquid conveyed to the pump at a 41 flows back. Continue 43 are shown a controllable shut-off member, a further shut-off element a controllable control valve 44 and 45.

[0044] 13 on vapor relief value unit 1 has a degassing device The. This vapor relief value unit 13 can have a float valve and a check valve and optionally a diaphragm, for example is preferably mounted at the upper end of the degassing container 11 and 16. Also at the upper end of the degassing container 16 11 17 2 a pressure sensor is mounted or alternatively at the hydrocyclone, which the pressure in the degassing vessel 11 or. Hydrocyclone measures 2.

[0045] The degassing, e.g. of cooling or heating water the- water mixture, in sequentially, degassing cycles takes place. By means of the pump is taken from the liquid carrying degassing cycle In a heating or cooling circuit liquid 41, through the diaphragm and 11 and from there into the degassing container 2 by the hydrocyclone from the liquid carrying heating or cooling circuit drawing returns to. Alternatively, by means of the pump 8 from the top-up feedline 41 by the liquid is through the diaphragm and 2 and from there into the degassing container 11 drawn from the hydrocyclone liquid carrying heating or cooling circuit fed back to

[0046] In a first step the pressure is reduced in the apparatus for degassing a liquid, so that gas is freely dissolved in the liquid. The release of the dissolved in the fluid in the form of gas bubbles are compounded by the use of a shield gas. In Hydrocyclone the released gas bubbles are bundled and enlarged, before the gas bubbles-containing liquid is supplied to the degassing device. Once the gas bubbles-containing liquid passes into the degassing device, the gas bubbles rise into the upper part of the degassing at 11 on and accumulate there. The pressure of the gas is not enough avoided, so as to be able to escape by the prevailing vapor relief value unit 13, because in the degassing vessel 11 at this time reduced pressure.

[0047] Reducing the pressure is carried out by controlling the liquid supply and or the liquid removal, for example by opening of the obturator 43 at 1 or by increasing the flow of the pump simultaneously ongoing pump 41, for example by controlling the speed of the pump in the device generates an enhanced gas bubble formation 41. The diaphragm, whereby the degasification will be promoted and therefore an improved degassing takes place in the device according to the invention.

[0048] In a second step the pressure is increased in the degassing container 11 again, so that in the top part of the degassing from the degassing vessel 11 13 11 is located is excreted vapor relief value unit gas via the. The increase in pressure is effected by controlling the liquid supply and/or discharge again, for example by (possibly [...] ) closing of the shut-off element 41 43 wherein the pump can be continued at the same time, or by reducing the flow of the pump 41, for example by controlling the speed of the pump 41 41 up to the switching off of the pump.

[0049] to a sudden increasing the pressure in the degassing container 11 for example the liquid removal A by stop arrival After-above- slosh of the liquid in the degassing container a can 11, with the result that the liquid can be let into the 13 go vapor relief value unit by deposition of substances dissolved in the fluid and the valve quickly leaking. In order to avoid this, for example, baffles or other elements can be incorporated into the degassing container vapor relief value mechanism 11 or the 13.

[0050] Under normal circumstances, it is not necessary, to permanently degassing, i.e. practically without interruption degassing cycledegassing cycle to follow on. Very little or almost no gas in more if the liquid is disposed, i.e. when the gas concentration in the liquid is not critical, the pump 41 can be switched off for some time, so as to avoid any unnecessary wear of the pump and to save energy. The according to the invention therefore points Method for degassing a liquid in a preferred variant a change-over between permanent degassing and temporary degassing on, wherein in the case of temporary degassing the pump 41 runs only from time to time. The switching automatically as a function of the gas concentration in the liquid is advantageously carried out. For the determination, whether a switchover is to take place or not, the gas concentration in the liquid can be determined in a direct or indirect way. The gas concentration in the liquid can be controlled by means of a probe, which reacts to contact with liquid 11 is mounted and on the degassing container, the determined, whether the liquid level in the degassing container reaches or not the height of the probe 11 at reduced pressure. The probe supplies its measurement values to a control unit, allows a conclusion to be made about the residual concentration of the gas in the liquid. To corresponds to a change-over is carried out as a function of the gas concentration in the liquid is mounted to carry out, the probe 11 at a height on the degassing container, the a gas concentration in the liquid, at which a switchover. The liquid level under reduced pressure in the degassing vessel 11 as far as from Weakening that the probe is no longer in contact with liquid, this detected the control unit 40 and gives the instruction that the gas present in the liquid is to be separated further still plenty in continuous operation. If but little gas is dissolved in the liquid, can lower the liquid level in the degassing container 2 is no longer or only very little, with the result that under vacuum the probe is surrounded with liquid. The control unit will then give the command that the degassing can be interrupted for a certain time.

[0051] In a second variant by means of a pressure measuring unit is an elevated pressure between the check valve and an orifice or an overflow valve 13 and the time period the vapor relief value unit, for which this pressure endures, measured. The values are supplied to the control unit. If much gas 11 is present and on the container-degassing valve unit 13 is separated in the degassing container, i.e. when the liquid has a high gas concentration to degassing, the pressure will rise at the measuring location and be present for a certain time by a certain measure. In little gas in the degassing container 11 is very little or not at all increase the pressure. The control unit evaluates the measurements then before switching between permanent degassing and temporary degassing from and will, in accordance with.

[0052] In a third variant the pressure-measuring unit can be a pressure sensor, which stores the pressure gradient between the non-return valve and the diaphragm or the relief valve and evaluated in a control unit.

[0053] In a fourth variant gas flow meter the amount of secreted gas is measured by means of a in each degassing cycle. The measurement values are passed on to the control unit.

[0054] In a fifth variant is measured by means of a pressure sensor 17 on the degassing container above the liquid in the degassing vessel 11 and also the pressure of the gas passed on to the control unit.

[0055] In any case can also be carried out a precise measurement of gas concentrations in the liquid, by different parameters Processing in the control unit.

[0056] By the resignation of gas or other liquid contained in the liquid carrying heating or cooling circuit loses the precipitates by volume. This volume loss can be compensated by adding liquid from the outside via a top-up feedline 8. The top-up feedline 21 opens into the feed line 8 in the shown device, so that the freshly added liquid still prior to insertion into the liquid carrying heating or cooling circuit is degassed. However, it can also be arranged in the degassing container 11 and, for example, on many other species, the discharge line or open out directly into the fluid-carrying heating or cooling circuit 4. 81 and 82 with a flow meter is a shut-off member 8 top-up feedline The provided, which preferably is a controllable solenoid valve.

[0057] 2 and 3 show two variants a pressure compensated The degasser Fig. Fig.. For this purpose, the device comprising in addition an expansion vessel 5 with a bellows 51 for receiving liquid. 2 and 3 an expansion vessel 5 is for pressure compensation in the Fig. 51 for receiving liquid with the liquid carrying with a bellows of a pressure-equalising line heating or cooling circuit 6, which comprises a pressure compensation valve 61, connected. In low-temperature line 7 is the circuit on the volume increase of the recirculating liquid, comprising a controllable shut-off member 71, a dirt filter 72,73 and 74 temperature layer container a further shut-off element or a heat exchanger, the withdrawn surplus volume. The liquid, the led via the 7 is taken through the pressure equalization line can be supplied either directly low-temperature line 6 the expansion tank 5, or via the discharge pipe 1 and then the pressure-equalising line 4 by the degassing device 6 into the expansion chamber. With cooled liquid having a temperature of 5 the expansion chamber can therefore, for example, less than 70 °C are acted upon. This embodiment permits the reliable use of a material for the bellows in the expansion tank, the have a higher permeability to gases, for example, at higher temperatures above 70 °C, in particular oxygen or nitrogen. Suitable is, for example, butyl rubber (HR) also, at a lower temperature of, for example, less than 70 °C which have sufficiently low permeability to gases such as oxygen and nitrogen. These gases have been already mentioned in the liquid a diffusion The disadvantages. The excess liquid is passed to the expansion chamber via a pressure compensating valve 5, where the liquid is stored under exclusion of air and atmospheric pressure.

[0058] In volume decrease can be recirculated the liquid of the recirculating liquid, so as to compensate for the missing volume. Takes place either through the discharge line 4 (2 Fig.) or this launch (Fig. 3) by 1 in the degassing device. In both cases, the pressure equalization line for the purpose of supplying liquid from the expansion tank is connected to the device before the pump. In this case the pump is used to discharge the liquid from the expansion vessel, which is supported against atmospheric pressure, back into the fluid-carrying heating or cooling circuit, which has an increased pressure, feed.

[0059] 62 arranged at the pressure-equalising line 6 is also a safety valve. Continue is reported an obturator 63 for draining liquid from said expansion chamber.

[0060] In particular, when the temperature of the liquid in the heating or cooling circuit is above a determined target temperature, for example above 70 °C, and the desired operating pressure in the heating or cooling circuit is exceeded by a certain tolerance value is 23 closes the controllable valve 7 and said pressure compensating valve in the 71 controllable valve. The low-temperature line 61 are opening up, so that cooled recirculating liquid from the heat exchanger 5 flows into the expansion chamber 74 or the temperature layer container. The Heat exchanger in a particular embodiment a container is, the cooler is in thermal contact with the environment. Once the pressure has decreased sufficiently, the controllable valve 61 again Close low-temperature line 7 and 71 in the said pressure compensating valve. The valve 23 can be again opened and the degassing operation patterns are projected can be continued again. If on the other hand by a certain tolerance value is fallen below the operating pressure, as long as the valve 61 is opened and closed so that liquid from the expansion chamber 23 and said pressure compensating valve 41 in the heating or cooling circuit conveyed via the pump, until the pressure in the fluid-carrying heating or cooling circuit is increased sufficiently. Patterns are projected the degassing operation can be continued again. An integrated solution allows wherein both operations to valve control sequence This alternately can be carried out in an apparatus.

[0061] a further process variant for pressure compensation in the present apparatus also makes possible the heating or cooling circuit when the temperature of the liquid in the receiving of the volume of expansion of the liquid by heating or cooling circuit is below a certain desired temperature, for example below 70 °C and the desired operating pressure in the heating or cooling circuit is exceeded by a certain tolerance value. In this case the controllable valve 71 remains open and the controllable valve 23 can be opened in the additionally low-temperature line 7. The pressure compensating valve opens 61, so that recirculating liquid from flowing directly out of the heating or cooling circuit in the expansion tank 5. Once the pressure has reduced sufficiently, said pressure compensating valve and the controllable valve 61 closes again and the degassing operation can be continued again 71. On the other hand, the operating pressure in this process variant is by a certain tolerance value if fallen below, as long as the valve 71 is closed and the valve 23 and, if present, said pressure compensating valve 41 opened and thus liquid from the expansion tank via the pump 61 in the heating or cooling circuit promoted, until the pressure in the fluid-carrying heating or cooling circuit is increased sufficiently. Here again the degassing operation can also be continued patterns are projected.

[0062] Fig. 4 shows a cross section through a unit which is formed by the degassing container and the hydrocyclone. The illustrated apparatus has a substantially cylindrical degassing vessel 11 on. Am container bottom 15 is mounted a liquid inlet 14, the projects into the interior of the degassing container 11, so that inflowing liquid is well distributed. The liquid inlet 15 is connected via a feed line 12 with the [...] 2. The [...] 2 is also formed by a generally cylindrically shaped container. On its Lower [...] laterally tangentially with the feed line 21 connected end of the is. Also at the lower end is disposed centrally of the effluent, with the feed line 11 is connected to the degassing container 12.

[0063] 5 illustrates the functioning of the unit Fig., [...] and is formed by the the degassing container.

[0064] The to degassing [...] 2 flows tangentially into the liquid in the lower part a, moves in a rotating movement on the wall there is diverted upwardly and downwardly. 2 is then derived [...] At the lower end of the said liquid through said discharge line 29. The [...] a same diameter over its entire 2 activity can chamber of the length, or show but a conical shape. Although the description refers to a perpendicular relative to the vertical direction arranged [...], understanding purposes defined and thus the directions up and down, the operating is largely independent of the process from the relative position of the can occupy any position [...][...] for a plumb direction and the, also, for example, horizontally.

[0065] The greater the density differential between the gas bubble and the surrounding medium and are each larger the particle diameter, the sooner the particles move in the radial direction, into which the centrifugal force is applied. Gases have a specific density which is significantly smaller than the density of the liquid. As a result that accumulates on the inner wall of the hydrocyclone gas-poor liquid which is withdrawn from the center is rich in bundled gas bubbles and the volume flow, which gas bubbles increase by the dwell as well as by the acting forces in the hydrocyclone is also.

[0066] Through the tangential entry into the cylindrical segment to a circular path and the liquid is forced upwardly in an upwardly directed vortex flows. By the upper cover 28 of the hydrocyclone comprises the vortex is 2, which liquid and gas bubbles, diverted and 2 again passed downwardly through the center of the hydrocyclone. This/liquid separation on reaching its lower end on 2 leaves then the hydrocyclone gas mixture the discharge line 29.

[0067] The liquid including bundled gas bubbles as liquid/gas mixture, which is then supplied via this supply line 29 emerges through the discharge line 12 of the degassing means 1.

[0068] the method according to the invention is achieved by the apparatus and according to the invention a clearly elevated degassing efficiency, which leads, for example that the volume of the de-gassing can be reduced, for example, five times. The method can reliably be operated without separate vacuum pump.