EP3168559B1 - Heating system for heating a gaseous treatment medium for a drier - Google Patents

Description

The invention relates to a method for heating a gaseous treatment medium for a device for treating a preferably web-like material according to claim 1 and an air treatment system according to claim 9.

The one from the US 5937538A as well as the DE 3832632A1 Known heating systems are mostly used for dryers for drying a preferably sheet-like material. The heating systems are used to heat a gaseous treatment medium with which a preferably web-like material can be dried within a drying chamber of the dryer. Such a heating system often has a gas burner as a heating device. The cooled treatment medium returned from the drying chamber is then mixed with a heating medium heated by the heating device for heating. The mixture is then fed as a heated gaseous treatment medium to the drying chamber to dry the sheet material. The EP 0421182A2 describes a device for drying a web-shaped material by means of a screen drum, in which the interior of the screen drum is not supplied with preheated ambient air and is then heated again with a gas burner. In recent years, however, there has been an increasing need for more efficient heating systems to save energy.

It is therefore an object of the present invention to provide a method for heating a gaseous treatment medium and an air treatment system which require less energy and are therefore more efficient.

The features of claims 1 and 9 serve to achieve this object.

In the prior art, the gaseous treatment medium is often warmed up within the treatment room. Similarly, in the prior art, the exhaust air is discharged directly from the treatment room and the fresh air is introduced directly into the treatment room. Thus, in the prior art, the gases that have different temperatures only have to mix within the treatment room. This often leads to undesirable and difficult to predict flow conditions within the treatment room.

The advantage of the present method is that the entire air treatment is carried out externally. Thus, the heated and prepared gaseous treatment medium is supplied to the treatment room at the desired temperature and does not have to mix in the treatment room first. This improves the flow conditions within the treatment room.

Before the recirculated, gaseous treatment medium is heated, part of the recirculated, gaseous treatment medium is discharged as exhaust air.

This has the advantage that the part that is to be discharged as exhaust air is not also warmed up. This saves energy.

The exhaust air can be used to heat the fresh air. This also has the advantage that energy can be saved.

The fresh air can be supplied to the recirculated, gaseous treatment medium before, during or after heating the recirculated, gaseous treatment medium.

The fresh air can be supplied to the recirculated, gaseous treatment medium after a part of the recirculated, gaseous treatment medium has already been discharged as exhaust air. This has the advantage that the maximum moisture has already been removed from the system.

The fresh air can be heated and the heated fresh air can be used to heat the recirculated, gaseous treatment medium.

The fresh air can first be mixed with a combustion exhaust gas from a heating device and this mixture can be fed as a gaseous heating medium to the recirculated, gaseous treatment medium and thus heat it up.

The heated and mixed with fresh air, gaseous treatment medium can be blown into the treatment room with the aid of a fan device, the fan device being arranged in the flow direction behind the heating system.

This has the advantage that energy can be saved.

Furthermore, the external air treatment has the advantage that the individual modules required for air treatment, such as the heating system and air circulation fan, can be set up at any location and can be exchanged or changed independently of the treatment room. The individual modules can e.g. be installed in another room so that the waste heat does not affect the system. Furthermore, e.g. the fan can be silenced separately.

An air preparation system for processing a gaseous treatment medium for a device, preferably a dryer, for treating a preferably web-like material with a gaseous treatment medium can be arranged externally from the treatment room of the device, the web-like material being treated in the treatment room. Fresh air can be supplied in the air treatment system to process the gaseous treatment medium and the gaseous treatment medium can be heated by means of a heating system.

Furthermore, the air treatment system comprises a circulating air fan, through which the gaseous treatment medium can be fed to the treatment room and the gaseous treatment medium already used for treatment can be returned from the treatment room to the air treatment system. The circulating air fan can be arranged behind the heating system in the direction of flow.
The recirculated, gaseous treatment medium can be heated in a heating system, in which case the gaseous heating medium can be introduced into the mixing chamber in such a way that when the gaseous heating medium is introduced into the mixing chamber, turbulences occur in the mixing chamber which also result in intensive mixing of the gaseous heating medium the recycled, gaseous treatment medium.

This has the advantage that the hot gaseous heating medium is more miscible with the recirculated gaseous treatment medium. The flow guidance results in better mixing of the gaseous heating medium and the gaseous treatment medium without having to install additional resistors. The consequence of this is that there are low pressure losses in the system and the fan output required for circulating the gaseous treatment medium can be reduced. Furthermore, hot strands are prevented, which lead to an uneven temperature distribution within the process.

When the gaseous heating medium is introduced into the mixing chamber, the gaseous heating medium can be deflected via guide elements, so that turbulence occurs in the mixing chamber when the gaseous heating medium is introduced into the mixing chamber.

The guide elements can be wing or blade elements.

The heating device can be a gas burner, a thermal oil heater or an electric heater.

The gaseous heating medium can comprise a mixture of fresh air and combustion exhaust gas from the gas burner. If an electric heater or the thermal oil heater is used, the gaseous heating medium can be the fresh air heated by the electric heater or the thermal oil heater or it can be a mixture of fresh air and gas heated by the electric heater or the thermal oil heater.

A prechamber can be provided for mixing the fresh air with the combustion exhaust gases of the gas burner. If an electric heater or thermal oil heater is used, there may be a prechamber for mixing the fresh air and the gas heated by the electric heater or thermal oil heater.

The antechamber is preferably arranged within the mixing chamber. This has the advantage that the waste heat from the prechamber can be used to heat the gases in the mixing chamber.

The gaseous treatment medium returned by the device, preferably the dryer, can be introduced into the mixing chamber in such a way that turbulence occurs in the mixing chamber when the returned treatment medium is introduced into the mixing chamber.

This also leads to an improved mixing of the recycled treatment medium with the gaseous heating medium.

The eddies of the recirculated gaseous treatment medium can rotate in the opposite direction to the eddies of the gaseous heating medium introduced into the mixing chamber. This also leads to better mixing of the two gaseous media.

The mixing chamber preferably has a cylindrical interior, wherein the recirculated, gaseous treatment medium can be introduced tangentially into the cylindrical mixing chamber, so that when the recirculated, gaseous treatment medium in the mixing chamber swirls occur in the mixing chamber.

When the recirculated, gaseous treatment medium is introduced into the mixing chamber, the recirculated, gaseous treatment medium can be deflected via guide elements, so that when the recirculated, gaseous treatment medium is introduced into the mixing chamber, swirls occur in the mixing chamber.

A flow straightener can be arranged in the flow direction behind the mixing chamber, which straightens the flow of the heated, gaseous treatment medium. The heated gaseous treatment medium is the mixture of gaseous heating medium and recirculated, gaseous treatment medium.

The flow straightener can be a channel running in the flow direction, which has flow baffles for rectifying the flow of the gaseous treatment medium. The flow baffles are aligned in the flow direction within the channel.

The flow straightener can be a sieve or perforated plate arranged in the cross-sectional area of the channel.

A device, preferably a dryer, can also be provided for the treatment, in particular for drying, of a preferably web-shaped material. The web-like material is in particular a textile web. The device can have a treatment room through which the material to be dried can be guided. The gaseous treatment medium located in the treatment room flows through the web-like material. The device can be a dryer and the web-like material can be dried by means of the gaseous treatment medium flowing through it. However, the device can also be a thermobonding device and the web-like material can be thermobonded by means of the flow through with the gaseous treatment medium.

Furthermore, the device has a heating system for heating the gaseous treatment medium. The heating system has a heating device and a mixing chamber, a gaseous heating medium heated by means of the heating device and a gaseous treatment medium returned from the treatment room being miscible in the mixing chamber. According to the present invention, it is preferably provided that the gaseous heating medium can be introduced into the mixing chamber in such a way that when the gaseous heating medium is introduced into the mixing chamber, turbulences occur in the mixing chamber, which produce intensive mixing of the gaseous heating medium with the recirculated, gaseous treatment medium.

The heating system can be arranged outside the treatment room.

• Rückführen eines bereits zum Behandeln des Guts verwendeten gasförmigen Behandlungsmediums,
• Einleiten des rückgeführten, gasförmigen Behandlungsmediums in eine Mischkammer,
• Einleiten eines erwärmten, gasförmigen Heizmediums in die Mischkammer zum Erwärmen des rückgeführten, gasförmigen Behandlungsmediums, wobei das gasförmige Heizmedium derart in die Mischkammer einführbar ist, dass Verwirbelungen beim Einführen auftreten, die eine intensive Durchmischung des gasförmigen Heizmediums mit dem rückgeführten, gasförmigen Behandlungsmediums erzeugen.

Furthermore, a method for heating a gaseous treatment medium for a device, preferably a dryer, for treating, in particular for drying, a preferably web-like material with a gaseous treatment medium can be provided, the method comprising the following steps:

• Returning a gaseous treatment medium already used to treat the material,
• Introducing the recirculated, gaseous treatment medium into a mixing chamber,
• Introducing a heated, gaseous heating medium into the mixing chamber for heating the recirculated, gaseous treatment medium, wherein the gaseous heating medium can be introduced into the mixing chamber in such a way that turbulences occur during the introduction, which produce intensive mixing of the gaseous heating medium with the recirculated, gaseous treatment medium.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings.

Fig. 1

eine Darstellung des Leitsystems für das gasförmige Behandlungsmedium,

Fig. 2

eine Seitenansicht der Trockenkammer,

Fig. 3

eine Darstellung der Luftaufbereitungseinrichtung,

Fig. 4

ein Heizsystem,

Fig. 5

eine Schnittansicht des Heizsystems aus Fig. 4.

They show schematically:

Fig. 1

a representation of the control system for the gaseous treatment medium,

Fig. 2

a side view of the drying chamber,

Fig. 3

a representation of the air treatment device,

Fig. 4

a heating system,

Fig. 5

a sectional view of the heating system Fig. 4 .

Fig. 1 shows a schematic representation of the control system of the gaseous treatment medium for a device for treating a, preferably web-like material with a gaseous treatment medium 40. In the exemplary embodiments shown, the device is a dryer 2. A heated, gaseous treatment medium 40 is supplied to a treatment room via a feed channel 6 fed. In the exemplary embodiment shown, the treatment room is a drying chamber 28.

In the drying chamber 28, as in Fig. 2 Shown in more detail, a preferably web-shaped material 12 is dried, the gaseous treatment medium flowing through the web-shaped material 12 to be dried and drying it in the process. This is related to Fig. 2 explained in more detail.

The gaseous treatment medium 30 already used for drying is discharged from the drying chamber 28 and returned to an air treatment device 3 via a channel 4. The gaseous treatment medium 30 already used for drying is colder than the heated, gaseous treatment medium 40 and it has the fact that it has the moisture of the web-like material 12 has a higher humidity than the heated, gaseous treatment medium 40.

A part of the recirculated, gaseous treatment medium 30 is removed in the air treatment device 3. The remaining part of the recirculated, gaseous treatment medium 30 is mixed with fresh air and heated and fed as a heated, gaseous treatment medium 40 to the drying chamber 28 via the feed channel 6.

The recirculated, gaseous treatment medium is always the gaseous treatment medium 30 which is recirculated from the treatment room or the drying chamber 28 and is already used for the treatment or drying and which is fed back to the air treatment device 3. The gaseous treatment medium or the heated, gaseous treatment medium is the gaseous treatment medium 40, which has already been prepared and is supplied to the treatment room or the drying chamber 28 for treatment or drying.

In Figure 2 the drying chamber 28 is shown schematically. The heated gaseous treatment medium 40 is introduced into the drying chamber 28. A gas-permeable drum 20 is arranged in the drying chamber 28. The gas-permeable drum 20 has a gas-permeable drum jacket 18.

A preferably web-shaped material 12 is introduced into the drying chamber 28 via a deflection roller 14. This web-shaped material 12 is transported by means of the drum 20 arranged on the drum jacket 18 in the direction of rotation of the drum 20. A part of the drum casing 18 is therefore always covered by a section of the web-shaped material 12. The gaseous treatment medium 40 located in the treatment chamber 28 passes through the sheet-like material 12 and the gas-permeable drum jacket 18 into the interior 22 of the drum 20 due to a negative pressure applied to the interior 22 of the drum 20. As a result, the sheet-like material 12 is dried. From the inside 22 of the drum 20, this is already drying used, gaseous treatment medium 30 via a channel 4, as already with respect Fig. 1 described, supplied to an air treatment device 3. After drying, the web-like material 12 is removed from the drying chamber 28 via a second deflection roller 16.

Fig. 3 shows an air treatment device 3, wherein the air treatment device 3 is merely a collection of lines and individual modules, which are explained in more detail below.

The recirculated, gaseous treatment medium 30 is partially discharged as exhaust air 32. This exhaust air 32 is fed to a heat exchanger 36 before being removed. Furthermore, fresh air 8 is supplied to the heat exchanger 36 and warmed up by the heat of the exhaust air 32.

The remaining part of the gaseous, recycled treatment medium 30 is introduced into a heating system 38. Likewise, the fresh air 8 ′ warmed by the heat exchanger 36 is fed to the heating system 38. The heating system 38 is related to FIGS Fig. 4th and 5 explained in more detail. The heated, gaseous treatment medium 40 emerges from the heating system 38 and is fed back to the drying chamber 28 via the feed duct 6 via a fan device 42.

In the Fig. 4th and 5 the heating system 38 is shown in more detail. The gaseous recycled treatment medium 30 is fed through an opening 31 to a mixing chamber 54. Likewise, a gaseous heating medium 49 heated by means of a heating device is introduced into the mixing chamber, the gaseous heating medium 49 being able to be introduced into the mixing chamber 54 in such a way that turbulence occurs in the mixing chamber 54 when the gaseous heating medium 49 is introduced into the mixing chamber 54. This results in intensive mixing of the gaseous heating medium 49 with the recirculated, gaseous treatment medium 30. In the present exemplary embodiment, the heating device is a gas burner 44.

The gaseous heating medium 49 is, as in Figure 5 shown, deflected via guide elements 53 when it is introduced into the mixing chamber 54 in such a way that when the gaseous heating medium 49 is introduced into the mixing chamber 54, swirls occur in the mixing chamber 54. The guide elements 53 are preferably wing or blade elements.

The gaseous heating medium 49 was heated by means of the gas burner 44. This happens because the combustion exhaust gases 46 of the gas burner 44 are mixed with the fresh air 8 ′ which has already been preheated. The mixture of combustion exhaust gas 46 and fresh air 8 ′ is the heated gaseous heating medium 49. The mixing of combustion exhaust gas 46 and fresh air 8 ′ takes place in a prechamber 50. The fresh air 8 ′ is supplied via an opening 48 along the circumference of the prechamber 50 on an end face 60 the antechamber 50 initiated. On the end face 62 of the prechamber 50 opposite the end face 60, the opening 52 is arranged, through which the heated, gaseous heating medium 49 enters the mixing chamber 54.

The hot combustion exhaust gas 46 is introduced axially and centrally into the cylindrical prechamber 50. This has the advantage that the hot combustion exhaust gas 46 is surrounded when fresh air 8 'is introduced. This means that no heat is lost as waste heat.

The pre-chamber 50 is also arranged within the mixing chamber 54, so that the waste heat from the pre-chamber 50 can also be used to heat the gaseous media in the mixing chamber 54 and no heat is lost.

The mixing chamber 54 shown has a cylindrical interior. The gaseous treatment medium 30 is introduced tangentially into the cylindrical mixing chamber 54. As a result, turbulence occurs in the mixing chamber 54 when the gaseous treatment medium 30 is introduced into the mixing chamber 54. The gaseous, recycled treatment medium 30 is preferably introduced in such a way that the eddies rotate in the opposite direction than the eddies into the mixing chamber 54 introduced gaseous heating medium 49. In this way, the recirculated, gaseous treatment medium 30 and the gaseous heating medium 49 mix very well. Alternatively, instead of the tangential introduction of the gaseous, recycled treatment medium 30, guide elements can also be provided, which lead to swirling when the gaseous treatment medium 30 is introduced.

Furthermore, as an alternative to the guide elements 53, which lead to swirling in the mixing chamber 54 when the gaseous heating medium 49 is introduced into the mixing chamber 54, it can also be provided that the gaseous heating medium 49 is likewise introduced tangentially into the cylindrical mixing chamber 54. The swirling of the recirculated, gaseous treatment medium 30 and the swirling of the gaseous heating medium 49 should always rotate in different directions, so that the two gaseous media are mixed more intensively.

Furthermore, the fresh air 8 'can also be introduced into the prechamber in such a way that turbulence occurs when the fresh air 8' is introduced into the prechamber. Furthermore, the combustion exhaust gases 46 can also be introduced into the prechamber such that swirling occurs when the combustion exhaust gas 46 is introduced into the prechamber 50. Likewise, the eddies of the fresh air 8 ′ and the combustion exhaust gas 46 can rotate in different directions. This would also lead to better mixing.

A conically tapering channel 56 is arranged downstream of the mixing chamber 54 in the direction of flow. The flow rate of the gaseous treatment medium 40 is increased by the tapered channel 56. The heated, gaseous treatment medium 40 can emerge from the opening 48 and be fed to the drying chamber 28 via the feed channel 6.

Furthermore, a flow straightener (not shown) can be arranged downstream of the mixing chamber 54 in the direction of flow. This can be a channel with in Channel direction aligned flow baffles. Alternatively or additionally, sieves or perforated plates arranged in the cross-sectional area of a channel can be used as flow straighteners.

Claims (10)

1. A method for heating a gaseous treatment medium (30, 40) for a device, preferably a dryer, for the treatment of a web-shaped material (12) with a gaseous treatment medium (40) by

   - introducing a heated gaseous treatment medium (40) into a treatment chamber (28) in which a drum with a gas-permeable drum shell (18) is arranged on which the web-shaped material (12) to be treated can be placed, the gaseous treatment medium (40) flowing through the web-shaped material (12) and the gas-permeable drum shell (18) into the interior of the drum,

   - discharging the gaseous treatment medium (30), which has already been used for treatment, as a recirculated gaseous treatment medium (30) from the interior of the drum and from the treatment chamber (28) to be processed externally,

   - processing the recirculated gaseous treatment medium (30), the recirculated gaseous treatment medium being processed by being warmed up, wherein a part of the recirculated gaseous treatment medium (30) is discharged as exhaust air (32) before the recirculated gaseous treatment medium (30) is warmed, and

   - supplying the processed gaseous treatment medium (40) to the treatment chamber (28) as the processed gaseous treatment medium (40),
   characterized in that processing the recirculated gaseous treatment medium (30) is effected such that the recirculated gaseous treatment medium (30) is mixed with fresh air (8, 8').
2. The method of claim 1, characterized in that the exhaust air (32) is used to warm the fresh air (8, 8').
3. The method of one of claims 1 to 2, characterized in that fresh air (8, 8') is first mixed with a combustion exhaust gas (46) of a heating means, and that this mixture is supplied to the recirculated gaseous treatment medium (30) as a gaseous heating medium (49), and that the former is warmed thereby.
4. The method of one of claims 1 to 3, characterized in that the warming of the recirculated gaseous treatment medium (30) is effected in a heating system (38), the heating system (38) comprising a heating means and a mixing chamber (54) for mixing at least a first gaseous heating medium (49) warmed by the heating means and the gaseous treatment medium (30) already used for treatment and recirculated from the device, wherein the gaseous heating medium (49) can be introduced tangentially into the cylindrical mixing chamber (54) or can be introduced into the mixing chamber and be deflected by means of guiding elements (53) such that turbulences occur in the mixing chamber (54) when the gaseous heating medium (49) is introduced into the mixing chamber (54), the turbulences causing an intensive mixing of the gaseous heating medium (49) with the recirculated gaseous treatment medium (30).
5. Method of claim 4, characterized in that the gaseous heating medium (49) can be deflected by guiding elements (53) when the gaseous heating medium (49) is introduced into the mixing chamber (54) so that turbulences occur in the mixing chamber (54) when the gaseous heating medium (49) is introduced into the mixing chamber (54).
6. Method of claim 4 or 5, characterized in that the gaseous treatment medium (30) recirculated from the device can be introduced tangentially into the cylindrical mixing chamber (54) or be introduced into the mixing chamber and be deflected by means of guiding elements (32) such that turbulences occur in the mixing chamber (54) when the recirculated treatment medium (30) is introduced into the mixing chamber (54).
7. Method of one of claims 4 to 6, characterized in that the introduction of the gaseous heating medium (49) and the treatment medium (30) into the mixing chamber (50) is effected such that the turbulences of the recirculated gaseous treatment medium (30) rotate in a direction opposite to the turbulences of the gaseous heating medium (49) introduced into the mixing chamber (54).
8. Method of one of claims 4 to 7, characterized in that the gaseous treatment medium (40) warmed and mixed with fresh air (8, 8') is blown into the treatment chamber (28) by means of a blower means (42), the blower means (42) being arranged downstream of the heating system (38) in the flow direction.
9. Air processing system (3) for the processing of a gaseous treatment medium (30, 40) according to the method of one of claims 1 to 8 for a device, preferably a dryer, for the treatment of a web-shaped material (12) with a gaseous treatment medium (40), the device comprising a treatment chamber (28) for the treatment of a preferably web-shaped material (12), a drum with a gas-permeable drum shell (18) being arranged in said chamber,
   wherein the air processing system (3) is arranged externally of the treatment chamber, wherein for the processing of the gaseous treatment medium fresh air can be supplied and the gaseous treatment medium can be heated by means of a heating system, wherein a part of the recirculated gaseous treatment medium (30) can be discharged and the remaining part of the recirculated gaseous treatment medium (30) can be mixed with fresh air and be warmed and can be supplied to the treatment chamber (28) as a warmed gaseous treatment medium (30) via a supply channel (6).
10. Air processing system of claim 9, characterized in that a blower is provided by which the gaseous treatment medium can be supplied to the treatment chamber and by which the gaseous treatment medium already used for treatment can be recirculated to the air processing system, wherein the blower is arranged downstream of the heating system in the flow direction.

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