DE102015116730B4 - Device and method for generating a hot gas containing water vapour - Google Patents

Abstract

Device (20) for generating a hot gas containing steam, having:an exhaust gas chamber (40) with an inlet (43) which can be connected to a burner (30) for burning a fuel and for generating a hot exhaust gas;a steam generating chamber (50 );a transmission wall (45) between the exhaust gas space (40) and the steam generation space (50) for transferring heat from the exhaust gas space (40) to the steam generation space (50);wherein an outlet (57) of the steam generation space (50) is so equipped with a propulsion nozzle ( 75) a jet pump (70) for compressing the exhaust gas is connected so that steam generated in the steam generation chamber (50) enters a mixing chamber (76) of the jet pump (70) through the propulsion nozzle (75) at high speed, with an outlet of the exhaust gas chamber (40) is connected to the mixing chamber (76) of the jet pump (70).

Description

The present invention relates to an apparatus and a method for generating a hot and steam-containing gas, which can be used, for example, for sterilizing soil or melting snow.

Hot steam is used, among other things, to sterilize agricultural soil. This process is also known as steaming. In this case, hot steam is generated by means of a particularly DE 10 2010 045 286 A1 device described introduced into the soil to be sterilized. The hot steam is usually generated by means of a steam boiler. As an alternative, in DE 10 2010 052 268 A1 describes a pulse jet steam generator comprising a pulse jet engine. A steam boiler takes up a lot of space and has a large mass, a pulse jet steam generator represents a relatively complex system, can only be operated with liquid or gaseous fuels and generates more noise than is usual and desirable in agriculture.

In GB 1 449 483 A describes a device for generating a mixture of water vapor and a cleaning fluid. An air-fuel mixture is fed to a combustion chamber 1 via a line 2 (page 1, lines 82 to 89) and burned therein. Combustion gases exit the combustion chamber 1 through an outlet 7 in the form of a convergent/divergent nozzle. The combustion chamber 1 is surrounded by a second chamber 10 (page 2, lines 7, 8) to which water is supplied via an inlet 9 (page 2, lines 5 to 7). A water-steam mixture generated in the second chamber 10 passes through an opening 11 from the second chamber 10 into the narrowed outlet 7 of the combustion chamber 1 and mixes there with the exhaust gases from the combustion chamber 1 (page 2, lines 12 to 17 ).

In DE 10 2006 014 853 A1 the generation of water vapor is described (paragraphs [0001], [0012]). A burner 1 is arranged below a burner chamber 6 (paragraph [0050]). The burner space 6 is surrounded by a vapor space 5 (ibid.). The steam chamber 5 is filled with an open-pored metal and/or ceramic foam, which increases the surface area for steam generation (paragraphs [0016], [0051]).

In DE 31 13 815 A1 describes a steam generator with a steam spray device to prevent frost damage in orchards (page 5, first paragraph). A fuel-air mixture is burned in a combustion chamber 75 (page 12, second paragraph). The hot exhaust gas exits the combustion chamber 75 through a nozzle 89 and flows past a water injector 96 which atomizes water (page 12, last paragraph).

In GB 773 048 A describes a device for heating a continuous flow of fluid (page 1, lines 9 to 12). A fuel-air mixture is combusted in an inner chamber 14 . The exhaust gas flows out of a tubular nozzle 18 at high speed, mixes with a cleaning liquid and flows into a venturi area 9 (page 2, lines 67 to 82).

In U.S.A. 4,480,985 a pulsating combustion is described. A combustion chamber 14 has a narrow, tubular exit 50 . A liquid is entrained in the exhaust gas rapidly escaping from the narrow exit 50 (col. 11, lines 4 through 26).

It is an object of the present invention to provide an improved apparatus and method for generating a hot and steam containing gas.

This object is solved by the subject matter of the independent claims.

Further developments are specified in the dependent claims.

A device for generating a hot gas containing water vapor comprises an exhaust gas space with an inlet which can be connected to a burner for burning a fuel and for generating a hot exhaust gas, a steam generation space and a transmission wall between the exhaust gas space and the steam generation space for transferring heat from the exhaust gas space to the steam generation space, an outlet of the steam generation space being connected to a driving nozzle of a jet pump for compressing the exhaust gas, and an outlet of the exhaust gas space being connected to a mixing chamber of the jet pump.

The device is intended and designed in particular for a burner that can be used conventionally to generate heat in stationary heating systems. Such burners are available on the market at low prices and in a wide variety and often have standard flanges for mounting on a stationary boiler. Such burners are usually neither intended nor designed to generate an overpressure. However, the exhaust gas from the burner can be conveyed and compressed by the jet pump, so that the burner does not have to generate overpressure.

The transmission wall hermetically separates the exhaust gas chamber and the steam generation wall from one another, so that a different pressure, in particular a higher pressure, can prevail in the steam generation chamber than in the exhaust gas chamber.

By mixing all the exhaust gas from the burner with the steam from the steam generation space in the mixing chamber of the jet pump, a gas mixture containing water vapor is generated, which can be introduced completely into soil to be sterilized or into snow to be melted, for example. All of the chemical energy originally contained in the fuel can therefore be used to sterilize soil or melt snow, and there is no heat loss through a chimney. Alternatively, only part of the exhaust gas generated by the burner can be introduced into the exhaust gas chamber permanently or controlled by flaps or valves depending on the operating state of the device.

The jet pump has no moving parts and therefore no wear and tear caused by friction and a long service life. The entire device can be of comparatively compact design, for example by flange-mounting a burner directly to the inlet of the exhaust gas chamber or directly fluidically connecting it in some other way. Furthermore, the output of the steam generation chamber can merge directly into one or more propulsion nozzles of the jet pump or be fluidly connected directly to the propulsion nozzle or nozzles of the jet pump. Furthermore, the outlet of the exhaust gas space can merge directly into the mixing chamber of the jet pump or be directly fluidly connected to it. Alternatively, between the burner and the inlet of the exhaust gas chamber and/or between the outlet of the steam generation chamber and the driving nozzle of the jet pump and/or between the outlet of the exhaust gas chamber and the mixing chamber of the jet pump, there can be pipelines and/or valves or flaps for setting flow resistances, volumes - Be provided or mass flows.

The device can be provided and designed to generate a hot gas containing water vapor for a wide range of applications, in particular for sterilizing soil and melting snow. The device can be adapted to the respectively required pressure of the hot gas containing water vapor by suitably dimensioning the jet pump.

The device can be provided and designed to generate a hot gas which alternatively or additionally contains the vapor of a substance other than water. In particular, another liquid can be added to the water to be evaporated or another substance can be dissolved in the water to be evaporated. Furthermore, instead of water, another substance can be used, which is converted into the gaseous phase by the heat generated by the burner and transferred from the transmission wall into the steam-generating space. This substance, the temperature and the residual oxygen content of the exhaust gas at the entrance to the mixing chamber of the jet pump and the mixing ratio of steam from the steam generation space and exhaust gas are then coordinated in particular in such a way that no ignition and no other chemical reaction of the substance takes place.

A device as described here also includes, in particular, an atomizing device for atomizing water in the steam-generating space.

A device as described here also includes, in particular, an atomizing device for atomizing water outside of the steam generation space, the atomizing device for atomizing water in the exhaust gas space or in a lumen of a connection between the exhaust gas space and the jet pump or fluid downstream of the outlet of the jet pump is arranged.

In particular, the atomizing device comprises one or more atomizing or spraying nozzles on or in a surface of the steam-generating space or in the interior of the steam-generating space or at another point in the device. Furthermore, the atomizing device can include one or more feed pumps for pumping water. In particular, the device comprises one or more atomizing nozzles or other atomizing devices inside and outside the steam-generating space. The mass flows injected into the steam generation chamber and elsewhere in the device can be controlled independently of one another by valves or separate and independently controllable feed pumps. This can make it possible to control different operating states of the device and to control the temperature, water vapor content, pressure, volume or mass flow and composition of the hot gas containing water vapor that is produced.

In a device as described here, the steam generation chamber in particular surrounds the exhaust gas chamber in the form of a jacket.

The steam generation space can partially, largely or - seperate the exhaust space from the entrance and from the exit of the exhaust space hen - completely surrounded. In other words, the exhaust gas space can be arranged partially or completely within the steam generation space.

In a device as described here, the exhaust gas space in particular surrounds the steam generation space.

The exhaust gas space can partially, largely or—apart from feed lines to the atomization device and from an outlet of the steam generation space—enclose the steam generation space completely, in particular in the form of a jacket. In other words, the steam generation space can be arranged partially or completely within the exhaust gas space.

In a device as described here, in particular the inlet of the exhaust gas chamber is provided and designed for connection to a burner which is provided and designed for a heating system for a building, with the device apart from the jet pump not having any further compressor for fresh air, for Includes exhaust gas from the burner or for the hot and steam-containing gas.

The entrance to the exhaust gas space is in particular structurally identical or identical in terms of its geometric dimensions to the part of a conventional stationary heating system for a building on which a burner is to be attached. If the device already includes a burner as described below, this can have a compressor for fresh air, so that the device does not include any further compressors apart from the jet pump and the compressor or fresh air fan of the burner.

Since burners for stationary heating systems for buildings are technically mature on the one hand and are manufactured in large numbers on the other, they have comparatively low prices and a long service life and reliability and can be replaced in the event of a defect or to adapt to another fuel or to change the performance of the Device can be replaced inexpensively.

A device as described here is designed in particular to provide the hot gas containing water vapor at a pressure which is above the ambient pressure.

A device as described here is designed in particular to provide the hot gas containing water vapor at a pressure which is 0.5 bar or 0.3 bar or 0.2 bar above the ambient pressure.

The jet pump ensures that the hot gas containing water vapor can be made available at its outlet at a pressure that is above the pressure in the exhaust gas chamber and above the ambient pressure. The suction effect of the jet pump at the exit of the exhaust gas chamber can also make a fresh air blower on the burner superfluous, so that this either does not have to be provided at all or can be switched off during operation of the device if sufficient steam is generated in the steam generation chamber to operate the jet pump. The excess pressure of the hot gas containing water vapor provided by the device compared to the ambient pressure can enable the hot gas containing water vapor to be introduced into the ground for sterilization or into snow or made available for other applications.

A device as described here also includes in particular a controller with an input for receiving a sensor signal at least either from a temperature sensor or from a pressure sensor or from a sensor for detecting a volume or mass flow and an output for providing a control signal at least either for a burner connected to the inlet of the exhaust space, or for a water pump for supplying water to the device, or for a valve for adjusting a volume flow of water to be supplied to the device, or for a damper or other valve at the entrance of the exhaust space, or between the outlet of the exhaust gas space and the mixing chamber of the jet pump, or between the outlet of the steam generation space and the motive nozzle of the jet pump, or fluidly downstream of the jet pump.

The controller is designed in particular to receive sensor signals from one or more temperature or pressure or volume flow or mass flow sensors in or on the exhaust gas chamber or in or on the steam generation chamber or in or on the jet pump. Using these or other sensors, the controller can detect the operating state of the device, for example heating of the device in a warm-up phase and when an operating temperature is reached. Depending on the recorded temperatures, pressures, volumetric or mass flows and/or other parameters, the controller can, for example, only start pumping water to one or more atomizing devices after a sufficient operating temperature has been reached. Furthermore, the controller can be provided and designed to set operating parameters of the device in such a way that the hot gas containing water vapor is at a predetermined pressure or an adjustable target pressure and/or a predetermined temperature temperature or an adjustable target temperature and/or with a predetermined water vapor content or an adjustable target water vapor content and/or with a predetermined volume or mass flow or an adjustable target volume or target mass flow.

A device as described here also includes, in particular, a burner, which is connected to the inlet of the exhaust space, for burning a fuel and for generating a hot exhaust gas.

The burner is fluidically connected to the inlet of the exhaust gas chamber in such a way that all of the hot exhaust gas generated by the burner or a predetermined part or an adjustable part of the hot exhaust gas generated by the burner reaches the exhaust gas chamber.

In a device as described here, the burner is provided and designed in particular for burning wood pellets or a methane-containing gas or another combustible gas.

The use of wood pellets, biogas, or other materials that a farm generates itself as a product, by-product, or waste is economically and logistically attractive to farm users of the device.

A system for sterilizing soil or for melting snow comprises a device as described here and an introduction device, which is connected to the outlet of the device, for introducing hot and steam-containing gas generated by the device into soil or snow.

In particular, the inlet device has features and properties as described in DE 10 2010 045 286 A1 are described. The device and the introduction device are in particular coordinated with one another in such a way that the device provides hot gas containing water vapor at the pressure, temperature, water vapor content, volume or mass flow required by the introduction device.

In particular, a system as described here further comprises a frame for supporting the device and the initiation device. In particular, the frame has wheels and/or is provided and designed for attachment to a lifting gear or a power lift of a tractor, a tractor or another tractor or another implement carrier. The device can have a lower mass for the same steam generation capacity or a higher steam generation capacity for the same mass than a conventional steam boiler. This can enable the device or the entire system to be arranged on the hitch or power lift of a tractor.

In a method for generating a hot and steam-containing gas, a fuel is burned and a hot exhaust gas is generated, heat is transferred from the exhaust gas to a steam generating space, steam is generated in the steam generating space, steam is supplied from the steam generating space to a motive nozzle of a jet pump, and exhaust gas is fed to a mixing chamber of the Jet pump supplied.

The method can be carried out in particular with the described steps, further steps or partial steps which correspond to features and properties of the device described here or correspond to them. The method can be carried out in particular with a device as described here.

• 1 eine schematische Darstellung eines Systems zum Sterilisieren von Erdreich;
• 2 eine schematische Darstellung eines weiteren Systems zum Sterilisieren von Erdreich;
• 3 eine schematische Darstellung eines weiteren Systems zum Sterilisieren von Erdreich;
• 4 eine schematische Darstellung eines weiteren Systems zum Sterilisieren von Erdreich;
• 5 ein schematisches Flussdiagramms eines Verfahrens zum Erzeugen eines heißen und wasserdampfhaltigen Gases.

Exemplary embodiments are explained in more detail below with reference to the attached figures. Show it:

• 1 a schematic representation of a system for sterilizing soil;
• 2 a schematic representation of another system for sterilizing soil;
• 3 a schematic representation of another system for sterilizing soil;
• 4 a schematic representation of another system for sterilizing soil;
• 5 a schematic flow diagram of a method for generating a hot gas containing water vapor.

1 shows a schematic representation of a system 10 for sterilizing soil 19. The system 10 comprises a device 20 for generating a hot gas containing water vapor and an introduction device 90 for introducing the hot gas containing water vapor into the soil 19. The introduction device 90 can be of the following type Presentation based on the 1 have different characteristics and properties. Alternatively, the system 10 can be configured to melt snow. In this case, in particular, the device can have similar or identical features and properties as described here and only the introduction device 90 can have features and properties that deviate from those described here.

The device 20 for generating a hot gas containing steam comprises a burner 30 with a fuel supply 32 for supplying wood pellets, biogas or another fuel, a fresh air fan 33 and a flange 34. The burner 30 is in particular for use on a boiler of a building heating system provided and trained. In particular, the flange 34 has dimensions adapted to such stationary boilers. Furthermore, the fresh air blower 33 is only provided and designed to overcome a low back pressure or a low flow resistance in the exhaust system.

The device 20 also includes an exhaust gas chamber 40 with an inlet 43 and an outlet 47. Apart from the inlet 43 and the outlet 47, the exhaust gas chamber 40 is enclosed in a fluid-tight manner, for example by a steel wall. The burner 30 is arranged and fastened at the entrance 43 of the exhaust gas space 40 . For this purpose, at the entrance 43 of the exhaust gas chamber 40, in particular an in 1 not shown and provided for the flange 34 on the burner 30 corresponding flange.

Furthermore, the device 20 comprises a steam generation space 50. The steam generation space 50 is arranged within the exhaust gas space 40. FIG.

In other words, the exhaust gas space 40 surrounds the steam generation space 50 completely or almost completely and partially in the form of a jacket. The transmission wall 45 separates the steam generation space 50 hermetically sealed from the exhaust gas space 40 in order to allow a pressure difference between the exhaust gas space 40 and the steam generation space 50 . The transfer wall 45 is designed to be thermally conductive in order to enable the transfer of heat from the exhaust gas space 40 into the steam generation space 50 . The steam generation space 50 has an outlet 57 .

Furthermore, the device 20 comprises a feed water reservoir 61, a feed water pump 62, a plurality of control valves 63, 64 and a plurality of atomizing nozzles 65, 69. One or—deviating from the representation in FIG 1 - A plurality of first atomizing nozzles 65 are arranged in the vapor generation space 50. One or - deviating from the representation in 1 - a plurality of second atomizing nozzles 69 are arranged outside the space 50 for generating steam. The feed water pump 62 is provided and designed to take water from the feed water reservoir 61 and to inject it via the control valves 63, 64 and the atomizer nozzles 65, 69 into the steam generation chamber 50 or at another point in the device 20 and there, in particular, to finely nebulize it. For this purpose, the feed water pump 62 is designed in particular to generate a pressure that is greater than the pressure in the steam generation chamber 50. The pressure in the steam generation chamber 50 can be a few bar, for fine nebulization of the water through the first atomizer nozzle 65 is that of the feed water pump 62, in particular one bar or several bars higher than the pressure in the steam generation chamber 50. The first control valve 63 can be used to control whether or at what times and/or how much water is injected through the first atomizer nozzle 65 into the steam generation chamber 50. The second control valve 64 can be used to control whether or at what times and/or how much water is injected via the second atomizer nozzle 69 downstream of the jet pump 70 .

Furthermore, the device 20 comprises a jet pump with a driving nozzle 75, a catching nozzle or a mixing chamber 76 and an outlet 79. The jet pump 70 has in particular between the mixing chamber 76 and the outlet 79 a constriction or a diffuser neck and between the diffuser neck and the Output 79 on an expansion or a diffuser. The propulsion nozzle 75 of the jet pump 70 is connected to the outlet 57 of the steam generation space 50 in such a way that steam generated in the steam generation space 50 can flow through the propulsion nozzle 75 into the mixing chamber 76 of the jet pump 70 at high speed. At the in 1 In the example shown, the outlet 57 of the steam generation chamber 50 merges into the propulsion nozzle 75 and is in particular formed in one piece with it. The outlet 47 of the exhaust gas space 40 is connected to the mixing chamber 76 of the jet pump 70 in such a way that exhaust gas can flow from the exhaust gas space 40 into the mixing chamber 76 of the jet pump 70 .

The second atomizing nozzle 69 is arranged at the outlet 79 of the jet pump 70 or fluidly downstream of the jet pump 70 in order to lower the temperature of the mixture of exhaust gas and steam provided by the device 20 and to increase the proportion of steam.

Furthermore, the device 20 includes a controller 80 with a sensor signal input 81 and a control signal output 86. Sensors 82, 83, 84 are coupled to the control signal input 81 of the controller 80, for example by point-to-point connections or, as in 1 indicated by dashed lines, via one or more branched or unbranched signal buses. The sensors 82, 83, 84 are arranged, for example, in the exhaust gas chamber 40, in the steam generation chamber 50 and/or downstream of the jet pump 70 in the fluid. The sensors 82, 83, 84 are designed in particular to record temperatures, pressures, mass and/or volume flows. The control signal output 86 of the controller 80 is with the burner 30, the feed water pump 62, the control valves 63, 64 and/or other actuators, in particular by point-to-point connections or, as in 1 indicated by dashed lines, coupled via one or more branched or unbranched signal buses. Around 1 not to be overloaded, the signal line to the first valve 63 is not shown.

The controller 80 is designed to receive sensor signals from the sensors 82, 83, 84 via the sensor signal input 81 and to detect the operating state of the device 20 in this way. Furthermore, the controller 80 is designed to send control signals to the burner 30, the feed water pump 62, the control valves 63, 64 and/or other actuators via the control signal output 86 and thereby to control the operation of the device 20. The controller 80 is designed to control the operation of the device 20 depending on the operating state of the device 20 and inputs from a user at an in 1 not shown to control user interface.

The outlet 79 of the jet pump 70 of the device 20 is connected to the introduction device 90 . In the example shown, the introduction device 90 comprises a fluid line 91 and a cultivator 92 with one or more outlet openings 93. The outlet 79 of the jet pump 70 is connected via the rigid or flexible fluid line 91 to fluid lines within the cultivator 92 in order to to conduct hot gas containing water vapor to the outlet openings 93 on the cultivator 92 and through them into the soil 19 .

The system 10 may be mounted on a frame (or frames) having wheels for driving over the surface of soil 19 to be sterilized and/or designed and configured for attachment to a front or rear hitch can. The controller 80 can have an interface to a vehicle controller of a tractor or another implement carrier and/or one or more interfaces to sensors and/or actuators on the induction device 90 .

During operation of the system 10 under the control of the controller 80 and/or manually, the fuel supply 32 of the burner 30 supplies wood pellets, gas, oil or other fuel and the fresh air blower 33 supplies fresh air into the burner 30. The fuel burns with the fresh air in a flame 37 in the exhaust gas chamber 40. The transfer wall 45 transfers heat from the flame 37 or the hot exhaust gas of the burner 30 in the exhaust gas chamber 40 into the steam generation chamber 50. The feed water pump 62 pumps water from the feed water reservoir 61 via the first control valve 63 to the first atomizer nozzle 65 in the steam generation chamber 50. The water is atomized by the first atomizing nozzle 65 into fine droplets, which vaporize due to the heat transmitted from the transmission wall 45 into the vaporizing space 50.

The steam generated in the steam generating space 50 flows - in 1 indicated by an arrow - through the (single) outlet 57 of the steam generation chamber 50 and the propulsion nozzle 75 into the mixing chamber 76 of the jet pump 70. Exhaust gas from the outlet 47 of the exhaust gas chamber 40 diffuses into the steam jet emerging from the propulsion nozzle 75 or is otherwise entrained in the jet of steam and mixes with it. The jet pump 70 generates an increase in pressure from the outlet 47 of the exhaust gas chamber 40 to the outlet 79 of the jet pump 70.

The jet pump 70, in particular the propulsion nozzle 75, the outlet 47 of the exhaust gas chamber 40, the mixing chamber 76 and its cross and longitudinal sections are dimensioned in particular so that the pressure in the outlet 47 of the exhaust gas chamber 40 is below the ambient pressure of the device 20 and at the outlet 79 of the Jet pump 70 a pressure that is a few to a few 100 mbar above the ambient pressure can be generated.

The pressure present at the outlet 47 of the exhaust gas space 40, which is close to or below the ambient pressure, enables the use of a burner 30 with a fresh air fan 33, which is only designed to generate a slight overpressure, or a burner 30 without a fresh air fan, or the fresh air fan 33 being switched off during the continuous Operation of the device 20. The pressure at the outlet 79 of the jet pump 70 above the ambient pressure makes it possible to overcome the flow resistance of the fluid line 91 and of fluid lines in the cultivator 92 and the flow resistance of the outlet openings 93 and to introduce the hot gas containing water vapor into the soil 19 to be sterilized .

The control of the burner 30 (in particular the fuel supply 32 and the fresh air blower 33), the feed water pump 62, the valves 63, 64 and/or other, in 1 Actuators, not shown, by the controller 80 as a function of the temperatures, pressures, mass and volume flows measured by the sensors 82, 83, 84 and other parameters enables the setting of different operating states of the device 20 and the entire system 10. In particular, the device 20 a hot gas containing water vapor with an adjustable pressure and temperature within certain limits and adjustable water vapor content.

2 shows a schematic representation of another system 10 for sterilizing soil 19, which in some features, properties and functions based on the 1 system shown. Features and properties are described below, in which the in 2 system 10 shown differs from that based on FIG 1 depicted differs.

At the in 2 In the system 10 shown, the steam generation chamber 50 is not arranged inside or largely inside the exhaust gas chamber 40, but encloses the exhaust gas chamber 40 largely in the form of a jacket. The exhaust gas space 40 is thus arranged largely within the steam generation space 50 . Correspondingly, part of the wall enclosing the exhaust gas space 40 forms the transmission wall 45 between the exhaust gas space 40 and the steam generation space 50.

At the in 2 example shown, the transmission wall 45 circular or spiral around in the plane of the 2 lying longitudinal axis of exhaust gas chamber 40 and steam generation chamber 50 arranged waves, similar to a metal bellows. The corrugation of the transmission wall 45 increases its area and thus increases the heat transfer from the exhaust gas chamber 40 into the steam generation chamber 50. Furthermore, the corrugation of the transmission wall 45 increases its elasticity in the longitudinal direction and thereby reduces mechanical stresses caused by temperature differences between the transmission wall 45 on the one hand and the outer wall of the steam generating space 50 on the other hand.

At the in 2 In the example shown, the outlet 57 of the steam generation chamber 50 and the propulsion nozzle 75 of the jet pump 70 are each annular. The driving nozzle 75 of the jet pump 70 encloses the outlet 47 of the exhaust gas chamber 40 in the form of a circular ring. Appropriate cross sections ensure that steam from the steam generation chamber 50 flows at high speed out of the propulsion nozzle 75 into the mixing chamber 76 of the jet pump 70 . Alternatively and deviating from the representation in 2 For example, a plurality of correspondingly smaller propulsion nozzles 75 each having a simply connected cross section (ie, for example, circular instead of annular) can be arranged over the circumference of the outlet 57 of the steam generation chamber 50 . As an alternative and different from the 2 a propulsion nozzle 75 can be provided with a single continuous cross section, which is similar to the embodiment according to FIG 1 is arranged in the middle of an annular outlet of the exhaust gas chamber 40 .

At the in 2 In the example shown, several or many first atomizer nozzles 65 are distributed over the circumference of the jacket-shaped steam generation space 50 . Around 2 not to overburden, only the supply line from the first control valve 63 to one of the first atomizer nozzles 65 is shown.

3 shows a schematic representation of another system 10 for sterilizing soil 19, which in some features, properties and functions based on the 1 and 2 systems shown. Features and properties are described below, in which the in 3 system 10 shown differs from that shown in FIG 1 and 2 systems shown differs.

This in 3 System 10 shown has similar to that based on FIG 1 system shown has a steam generation space 50 which is arranged within or largely within an exhaust gas space 40 . In contrast to the one based on the 1 In addition to one or more first atomizer nozzles 65 within the steam generation chamber 50, the system shown is one or - as in 3 indicated - several second atomizer nozzles 67 arranged in the exhaust chamber 40 . The second atomizing nozzles 67 are connected to the second control valve 64 . Around 3 not to overburden, the feed line from the second control valve 64 is shown only to one of the second atomizer nozzles 67 .

Alternatively and deviating from the representation in 3 For example, the second atomizer nozzles 67 can be arranged closer to the burner 30 in order to reduce the thermal load on the outer wall enclosing the exhaust gas space 40 . Furthermore, alternatively and deviating from 3 additionally similar to the based on the 1 and 2 systems shown, one or more atomizer nozzles may be arranged at the outlet 79 of the jet pump 70 or fluidly downstream of the jet pump 70.

4 shows a schematic representation of another system 10 for sterilizing soil 19, which in some features, properties and functions based on the 1 until 3 systems shown. Features and properties are described below, in which the in 4 system 10 shown differs from that shown in FIG 1 until 3 systems shown differs.

This in 4 System 10 shown includes a device 20 with an exhaust gas chamber 40, which is similar to the device of the basis of 2 The system shown is largely surrounded by a steam generation chamber 50 in the form of a jacket.

Unlike the one based on the 2 system shown, the transmission wall 45 between the exhaust gas chamber 40 and the steam generation chamber 50 is not wavy, but smooth and in particular partially circular-cylindrical.

Furthermore, this distinguishes in 4 system 10 shown differs from that based on FIG 2 represented by the fact that a or - as in 4 indicated - several second atomizer nozzles 67 are arranged in the exhaust chamber 40 . Similar to related to 3 already mentioned, can also be based on the 4 In the system 10 shown, the second atomizer nozzles 67 can be arranged closer to the burner 30 and in particular in such a way that they reduce the thermal load on the transmission wall 45 between the exhaust gas chamber 40 and the steam generation chamber 50 .

Furthermore, alternatively and deviating from the representation in 4 and similar to the based on the 1 and 2 systems shown, one or more further atomizer nozzles can be arranged at the outlet 79 of the jet pump 70 or fluidly downstream of the jet pump 70 .

The devices 20 for generating hot and steam-containing gases based on the 1 until 4 The systems shown can generate hot gases containing water vapor not only for sterilizing soil, but also for melting snow and other applications. For this purpose, the devices 20 can in particular also be coupled to devices that have features and properties that differ from the introduction device 90 .

5 shows a schematic flow diagram of a method for generating a hot and steam-containing gas and for sterilizing soil. That based on 5 The method shown can also be carried out with devices and systems that are based on the illustrations 1 until 4 have different characteristics and properties. Nevertheless, the following reference symbols from the 1 until 4 used to understanding the 5 to simplify.

In a first step 101 , wood pellets, biogas or another fuel provided by a fuel supply 32 are burned in an air stream conveyed by a fresh air fan 33 of a burner 30 at an inlet 43 of an exhaust gas chamber 40 . This creates a flame 37 and hot exhaust gases in the exhaust chamber 40.

In an optional second step, water in the hot exhaust gas in the exhaust gas space 40 is evaporated. For this purpose, water is conveyed by a feed water pump 62 from a feed water reservoir 61 to an atomizer nozzle 67 and atomized by the atomizer nozzle or broken down into small droplets which evaporate in the hot exhaust gas.

In a third step 103 , heat is transferred from the exhaust gas space 40 to a steam generation space 50 through a transmission wall 45 . The heat is transferred by thermal conduction in the fluid-tight transfer wall 45.

In a fourth step 104, steam is generated in the steam generating space 50. For this purpose, a feed water pump 62 conveys water from a feed water reservoir 61 to one or more atomizer nozzles 65 in the steam generation chamber. The water is atomized by the atomizing nozzles 65 or broken down into fine droplets which evaporate due to the heat transmitted from the transmission wall 45 . The generation of steam in the steam generation space 50 creates excess pressure in the steam generation space 50.

In a fifth step 105, steam from the steam generation space 50 is supplied to a motive nozzle 75 of a jet pump 70 and enters a mixing chamber 76 of the jet pump 70 from the motive nozzle 75 at high speed. The steam can be fed to one or more motive nozzles, each with a simply connected cross section, and/or one or more motive nozzles, each with a circular cross section.

In a sixth step 106, exhaust gas from the exhaust gas chamber 40 is supplied to the mixing chamber 76 of the jet pump 70. The fast jet of steam from the driving nozzle 75 of the jet pump 70 entrains the exhaust gas in its direction of flow and generates an increase in pressure from the outlet 47 of the exhaust gas chamber 40 to the outlet 79 of the jet pump 70.

In an optional seventh step 107 , water in the mixture of exhaust gas and steam generated by the jet pump 70 is evaporated at the outlet 79 of the jet pump 70 or downstream of the jet pump 70 . For this purpose, water is conveyed by a feedwater pump 62 from a feedwater reservoir 61 to one or more atomizer nozzles 69 and is atomized there or broken down into small droplets which evaporate in the mixture of exhaust gas and steam.

The first seven steps 101, 102, 103, 104, 105, 106, 107 represent a method for generating a hot gas containing water vapor. This method can be used together with a subsequent eighth step 108, in which the hot gas containing water vapor is in soil 19 is initiated constitute a method for sterilizing soil. Alternatively, the first in seven steps 101, 102, 103, 104, 105, 106, 107 hot gas containing water vapor is introduced into snow in another eighth step in order to melt it or to be used in some other way.

Reference List

10

System for sterilizing soil or melting snow

19

soil to be sterilized

20

Device for generating a hot gas containing water vapour

30

burner

32

fuel supply

33

fresh air blower

34

Flange on burner 30

37

flame

40

exhaust space

43

Entrance to the exhaust chamber 40

45

Transmission wall between exhaust gas space 40 and steam generation space 50

47

Exhaust chamber exit 40

50

steam generating room

57

Steam generating room exit 50

61

feed water reservoir

62

feed water pump

63

first control valve

64

second control valve

65

first atomizer nozzle (in the steam generation room 50)

67

second atomizer nozzle (outside the steam generation space 50, namely in the exhaust gas space 40)

69

second atomizing nozzle (outside the steam generating space 50, namely fluidly downstream of the jet pump 70)

70

jet pump

75

Jet pump motive nozzle 70

76

Mixing chamber or catching nozzle of the jet pump 70

79

Jet pump outlet 70

80

Controller for controlling the device 20

81

Controller sensor signal input 80

82

first sensor

83

second sensor

84

third sensor

86

Control signal output of the controller 80

90

Discharge device for discharging gas into the ground or snow

91

fluid line

92

Cultivator with fluid line

93

exit port

101

first step (burning a fuel and producing a hot exhaust gas)

102

second step (evaporation of water in the hot exhaust gas; optional)

103

third step (transferring heat from the exhaust space to a steam generating space)

104

fourth step (generating steam in the steam generating room)

105

fifth step (supplying steam from the steam generating space to a driving nozzle of a jet pump)

106

sixth step (supplying exhaust gas to a mixing chamber of the jet pump)

107

seventh step (evaporation of water in the mixture of exhaust gas and steam; optional)

108

eighth step (introducing the mixture of exhaust gas and steam into soil or snow)

Claims (11)

Device (20) for generating a hot gas containing water vapor, having: an exhaust gas space (40) with an inlet (43) which can be connected to a burner (30) for burning a fuel and for generating a hot exhaust gas; a steam generating space (50); a transfer wall (45) between the exhaust space (40) and the steam generating space (50) for transferring heat from the exhaust space (40) to the steam generating space (50); an outlet (57) of the steam generation chamber (50) being connected to a propulsion nozzle (75) of a jet pump (70) for compressing the exhaust gas in such a way that steam generated in the steam generation chamber (50) passes through the propulsion nozzle (75) at high speed into a mixing chamber (76) of the jet pump (70) enters, an outlet of the exhaust gas chamber (40) being connected to the mixing chamber (76) of the jet pump (70). Apparatus (20) according to the preceding claim, further comprising: an atomizing device (65) for atomizing water in the steam generating space (50). Apparatus (20) according to any one of the preceding claims, further comprising: an atomizing device (67, 69) for atomizing water outside the steam generating space (50), wherein the atomizing device (67) for atomizing water is arranged in the exhaust space (40) or in a lumen of a connection (91) between the exhaust space (40) and the jet pump (70) or fluidly downstream of the outlet of the jet pump (70). Device (20) according to one of the preceding claims, in which the steam generation space (50) surrounds the exhaust gas space (40) in the form of a jacket. Device (20) according to one of Claims 1 until 3 , in which the exhaust gas space (40) surrounds the steam generation space (50). Apparatus (20) according to any one of the preceding claims, wherein the inlet (43) of the exhaust gas space (40) is provided and designed for connection to a burner (30) which is provided and designed for a heating system for a building, apart from the jet pump (70), the device (20) has no further compressor for fresh air, for exhaust gas from the burner or for the hot gas containing steam. Device (20) according to one of the preceding claims, wherein the device (20) is designed to provide the hot gas containing water vapor at a pressure which is above the ambient pressure. Device (20) according to any one of the preceding claims, wherein the device (20) is designed to provide the hot gas containing steam at a pressure which is 0.5 bar or 0.3 bar or 0.2 bar above that ambient pressure is. Apparatus (20) according to any one of the preceding claims, further comprising: a controller (80) with an input (81) for receiving a sensor signal at least either from a temperature sensor (82, 83, 84) or from a pressure sensor (82, 83, 84) or from a sensor for detecting a volume or mass flow; an output (86) for providing a control signal at least either for a burner (30) connected to the input (43) of the exhaust gas chamber (40) or for a water pump (62) for supplying water to the device (20) or for a valve (63, 64) for adjusting a volume flow of water to be supplied to the device, or for a butterfly valve or other valve at the entrance to the exhaust space (40) or between the exit (47) of the exhaust space (40) and the mixing chamber (76 ) the jet pump (70) or between the outlet (57) of the steam generation space (50) and the driving nozzle (75) of the jet pump (70) or fluid downstream of the jet pump (70). Apparatus (20) according to any one of the preceding claims, further comprising: a burner (30) connected to the inlet (43) of the exhaust space (40) for burning wood pellets or other fuel and producing a hot exhaust gas. Process for generating a hot gas containing water vapor, comprising the following steps: combusting (101) a fuel and producing a hot exhaust gas; transferring (103) heat from the exhaust gas in an exhaust space (40) through a transmission wall (45) between the exhaust space (40) and a steam generating space (50) into the steam generating space (50); generating (104) steam in the steam generating space (50); Feeding (106) of steam from the steam generation space (50) to a propulsion nozzle (75) of a jet pump (70), so that steam generated in the steam generation space (50) can flow through the propulsion nozzle (75) at high speed into a mixing chamber (76) of the jet pump (70) entering; Supplying (107) exhaust gas from the exhaust gas space (40) to the mixing chamber (76) of the jet pump (70).

Images