Dryer for a textile material web

Abstract

The invention relates to a dryer (1) for a textile web (5), comprising at least two vertically arranged dryer chambers (2T1, 2T2), wherein each dryer chamber (2T1; 2T2) has a drum (T1; T2) with flow channels (17T1, 17T2) arranged on both sides thereof, and wherein each dryer chamber (2T1; 2T2) has a separate additional chamber (11T1, 11T2) which has channels (13T1, 13T2, 15T1, 15T2) for supplying fresh air (12T1, 12T2) and for extracting exhaust air (14T1, 14T2), wherein the additional chambers (11T1, 11T2) are arranged between an end face of the associated dryer chamber (2T1; 2T2) and a separate heating and fan chamber (24). The invention is characterized in that the channels (13T1, 15T1) for supplying fresh air (12T1) and extracting exhaust air (14T1) from the lower dryer chamber (2T1) are located at the upper dryer chamber (2T2) and at the upper auxiliary chamber (11T2).The invention further relates to a method for drying a textile web.

Description

[0001] The invention relates to a dryer for a textile web according to the preamble of claim 1, and to a method for drying a textile web.

[0002] Dryers are known for drying textile webs, in which one or more drums are arranged in a housing. A textile web is fed into the dryer through an opening in the drying chamber, wrapping itself around a large portion of the drum's circumference, and then exiting the drying chamber. Fresh air is typically also supplied through this opening. This air is heated within the drying chamber and mixed with the circulating air to maximize its moisture absorption capacity. As the web wraps around the drum, the mixture of circulating and fresh air flows through it, absorbing at least some of the moisture, and is then discharged through the interior of the drum. A portion of this airflow is extracted as exhaust air.The moist exhaust air is extracted via ducts above the drums, which, due to the rotating drums, requires complex and expensive sealing and is maintenance-intensive. To prevent the suction effect from the dryer's surroundings, supply lines or ducts for fresh air have been retrofitted to the dryer chamber; these can, for example, be coupled with a heat exchanger to warm the fresh air.

[0003] A previously described dryer is disclosed in DE 102009016019 A1. In dryers of this design, the fresh air circulation occurs at a right angle to the direction of the moist air exhaust, i.e., at a right angle to the drum axis, which disrupts the air circulation within the dryer chamber. A further disadvantage, due to space constraints, is the often complex modification required, as the fresh air duct cannot be coupled with a heat exchanger. Since the dryers are positioned very close together in a series of different process units that sequentially treat the textile web, there is often insufficient space to retrofit a fresh air duct between the units.

[0004] DE 1729499 A1 discloses a dryer in which several drums are arranged in a staggered series, with the drums being drawn in by fans on both sides. A flow chamber is arranged within the dryer between the drums and the fans, from which a portion of the used and moisture-enriched air is extracted.

[0005] The arrangement of the dryer drums requires a lot of space in a system, so convection dryers are known in which the dryer drums are arranged vertically above one another.

[0006] The object of the invention is to create a dryer for a textile web that can be operated with lower energy consumption.

[0007] The invention solves the stated problem by the teaching according to claims 1 and 9; further advantageous features of the invention are characterized by the dependent claims.

[0008] According to the technical teaching of claim 1, the dryer for a textile web comprises at least two vertically arranged drying chambers, each drying chamber having a drum with flow channels arranged on both sides. Furthermore, each drying chamber has a separate auxiliary chamber with channels for supplying fresh air and extracting exhaust air. The auxiliary chambers are arranged between an end wall of the associated drying chamber and a separate heating and fan chamber.

[0009] The invention is characterized in that the channels for supplying fresh air and extracting exhaust air from the lower drying chamber are located adjacent to the upper drying chamber and the upper auxiliary chamber. The fresh air for the lower drying chamber is preheated by the heat dissipated from the upper drying chamber and the upper auxiliary chamber, and can therefore absorb more moisture. At the same time, the energy consumption in the lower drying chamber decreases. Since the lower drying chamber has a higher temperature than the upper drying chamber, the exhaust air and waste heat from the lower drying chamber also have a higher temperature, thus warming the upper auxiliary chamber and the upper drying chamber.

[0010] Preferably, the flow channels are separated from the drums by perforated screen covers. This ensures a uniform airflow along the working width of the web or along the length of the drum.

[0011] The drums can have air guide cylinders, which are preferably adjustable. The flow intensity can thus be adjusted across the working width of the web, allowing, in particular, the residual moisture content of the web edges to be controlled.

[0012] Because the drying rooms are completely separated from each other except for a passage opening for the fabric web, two thermally independent drying rooms are created, whose respective waste heat can be used differently.

[0013] Each drying room has its own heating and ventilation room, whose fan is designed to extract the exhaust air from the drying room. In addition to the drying rooms, the auxiliary chambers and the heating and ventilation rooms are also separated from each other, so that two thermally separated drying systems are arranged one above the other. These systems dry one web of material using a flow-through principle, and the waste heat from each can be used for the other drying system.

[0014] Within the heating and fan compartments, devices for heating the drying air are installed. These can be heat exchangers, gas burners, electric heaters, or a combination thereof. Depending on the web of material being produced, this results in a high degree of flexibility for the dryer operator in terms of operation and energy costs.

[0015] The dryer has an inlet for the web of material, two deflection rollers at a through-opening to guide the web from the lower drum to the upper drum, and an outlet for removing the web from the dryer. Except for the through-opening for the web, the upper and lower dryer chambers, along with all associated components (additional chamber, heating and fan chamber, fresh air and exhaust air ducts), are completely thermally separated from each other.

[0016] The inventive method for drying a textile web comprises two vertically arranged drying chambers, each with a drum, into which a separate flow of heated drying air is directed. The web is first guided around the lower drum and then around the upper drum, with the heated drying air flowing through the web and being discharged via an interior space of the drums. Fresh air is supplied to each drying chamber in a separate upper and lower auxiliary chamber, and exhaust air is discharged via the respective auxiliary chamber, with the fresh air being mixed with the drying air within the auxiliary chambers. The inventive method is characterized in that the fresh air for the lower drying chamber is guided past the upper auxiliary chamber and the upper drying chamber and is thereby heated.

[0017] The fresh air for the lower drying chamber is additionally heated by the heat dissipated from the upper drying chamber and the upper auxiliary chamber, allowing it to absorb more moisture. At the same time, the energy required by the heating elements is reduced. Since most of the heating power is needed in the lower drying chamber, the required heating power can be reduced while maintaining the same evaporation rate.

[0018] If the exhaust air for the lower drying chamber is also routed past the upper auxiliary chamber and the upper drying chamber, the exhaust air can be used to heat the upper auxiliary chamber and the upper drying chamber due to the higher temperature level of the lower drying chamber.

[0019] Preferably, the lower drying chamber is operated at a temperature at least 30°C, preferably at least 60°C, and particularly preferably at least 90°C, higher than the upper drying chamber. The temperature difference depends on the dryer's temperature setting, which can be adjusted depending on the fiber mixture being processed.

[0020] Preferably, the heated drying air is guided along a flow channel before passing through the drums and its flow velocity is homogenized by means of perforated screen covers. This ensures a uniform airflow across the working width of the web or along the length of the drum.

[0021] Furthermore, the drying intensity of the web can be adjusted across the working width by means of air guide cylinders inside the drums. In particular, the residual moisture content of the web edges can be controlled in this way.

[0022] Because the fabric web wraps around each drum by at least 280°, a higher drying intensity is achieved with a vertical drum arrangement compared to drums arranged side by side. Due to their design, this degree of wrap is often not possible with in-line dryers.

[0023] Preferably, within the additional chambers, the exhaust air is discharged from the drying air at the point where it has the lowest temperature or energy level.

[0024] The fresh air and the drying air are heated within the respective heating and fan room, which is done via heat exchangers, gas burners or an electric heater or a combination thereof.

[0025] The features of the invention make it possible to arrange the fresh air and exhaust air connections on the drying chambers in such a way that the airflow for the drying process in the drying chamber and inside the drum is not disturbed. The additional chamber allows the drying air to expand, thus reducing its flow velocity many times over as it exits the drum. The exhaust air is extracted from the additional chamber with the least possible impact on the drying process. Furthermore, the negative pressure in the additional chamber allows fresh air to be drawn in freely and directed into the heating and fan compartment.

[0026] It is advantageous to position each auxiliary chamber between one end of the drying chamber and the associated heating and fan compartment. For energy efficiency, extracting the exhaust air from the drying air in the auxiliary chamber is most effective, as the drying air has the lowest energy level there. This minimizes energy loss through the exhaust air. The result is a streamlined solution for the drying process that can be positioned between the units arranged in series, regardless of the available space. Furthermore, the clearly defined interface allows for the use of heat recovery under optimal conditions, further improving the energy balance.

[0027] Within each additional chamber, the fresh air mixes with the drying air. Because the associated heating and fan compartment contains means for heating both the fresh air and the drying air, the heated drying air has only a short path to the drying chamber, where it does not cool down.

[0028] The arrangement of the fans in the respective heating and fan compartments for circulating the drying air has the advantage that the dryer can be built compactly.

[0029] Within the additional chambers are connections through which the drying air can be extracted from the dryer chamber or the drums by means of fans. These connections, in turn, can be designed to optimize airflow and minimize flow losses.

[0030] The invention is explained in more detail below with reference to a possible schematic embodiment. It shows: Figure 1: a schematic representation of a convection dryer in a perspective partial section; Figure 2: a sectional view of the front of the dryer; Figure 3: a schematic side view of the convection dryer according to the invention.

[0031] In the Figures 1 to 3 A dryer 1 in the form of a convection dryer is shown, comprising two drums T1, T2 arranged one above the other, each with an associated drying chamber 2 T1, 2 T2. Each drying chamber 2 T1, 2 T2 is formed by a drum T1, T2 with flow channels 17 T1, 17 T2 arranged on both sides. The drying chambers 2 T1, 2 T2 are completely separated from each other except for a passage opening 16 for the web 5.

[0032] A web of material 5 is fed into the dryer 1 via an inlet 6 by means of a deflecting roller 7 and guided via a first deflecting roller 8.1 at the passage opening 16 into the lower dryer chamber 2 T1 around the lower drum T1. According to the illustration of the Figure 2The web 5 circulates counterclockwise around the lower drum T1. After the web 5 has almost completely circulated around the lower drum T1, it is guided through the opening 16 into the upper drying chamber 2 T2 and circulates clockwise around the upper drum T2 until it is guided out of the dryer 1 at the second deflection roller 8.2 at the opening 16 via the outlet 9 on the outlet roller 10. During its passage through the drying chambers 2, the web 5 is exposed to heated drying air. This drying air absorbs the moisture from the web 5 and is extracted through the interior of the drums T1 and T2. The lower drum T1 can reach a temperature of approximately 200°C, while the upper drum T2 can reach a lower temperature of approximately 110°C.Depending on the fiber composition of the web 5, the temperature level of the lower drum T1 may only be 180° or 170°, so that the corresponding lower temperature level of the upper drum T2 is 120° or 140°, respectively. This results in temperature differences of 90°, 60°, or 30° between the lower and upper drums, which can be advantageous for different fiber blends. The web 5 wraps around each drum T1 and T2 by approximately 280°.

[0033] Each of the two drying chambers 2T1, 2T2 has an additional chamber 11T1, 11T2, into which the fresh air ducts 13T1, 13T2 12T1, 12T2 and the exhaust air ducts 15T1, 15T2 14T1, 14T2 open. The additional chambers 11T1, 11T2 are separated from each other by a horizontal partition 19, and also from the drying chambers 2T1, 2T2 by two vertical partitions 18T1, 18T2, and are constructed separately. The heating and fan chambers 24 are located adjacent to the additional chambers 11T1, 11T2. The drying chambers 2T1, 2T2 are connected to the heating and fan chambers 24 by air ducts (not shown) located above and below the drums T1, T2. The additional chambers 11 T1 , 11 T2 are connected to the drying chambers 2 T1 , 2 T2 via the end-face openings of the drums T1, T2.

[0034] The heating elements 23 generate drying air, which is mixed with fresh air 12 T1, 12 T2 in the auxiliary chambers 11 T1, 11 T2. The drying air flows through the flow channels 17 T1, 17 T2 arranged on both sides of the drums T1, T2, through the perforated screen covers 4 T1, 4 T2, which ensure a uniform drying air, and through the web 5 into the drum T1, T2. Air guide cylinders 3 T1, 3 T2 are arranged inside the drums T1, T2, the perforation of which can be adjustable. This allows the drying capacity to be adjusted across the working width, so that the edges of the web 5 do not exit the dryer 1 too dry, but also not with excessive residual moisture. The drying air is loaded with moisture and extracted as exhaust air 14 T1 , 14 T2 from the drums T1, T2 via the fans 21.Within the additional chambers 11 T1 , 11 72 the moisture-laden and heated exhaust air 14 T1 , 14 T2 is mixed with the fresh air 12 T1 , 12 T2 and the drying air, so that part of the exhaust air 14 T1 , 14 T2 is energetically re-entered into the drying process cycle.

[0035] Unlike the prior art, here the fresh air 12 T1, 12 T2 does not flow directly into the drying chambers 2 T1, 2 T2, but first into the auxiliary chambers 11 T1, 11 T2, where further heating occurs through mixing with the loaded exhaust air 14 T1, 14 T2 after passing through the web 5. In previous designs, this mixing of the fresh air 12 T1, 12 T2 with the drying air took place before it passed through the web 5, thus influencing the temperature of the drying air before it passed through the web 5. Utilizing the temperature difference between the exhaust air 14 T1, 14 T2 and the fresh air 12 T1, 12 T2 is sufficient to further increase the thermal efficiency of the dryer 1.

[0036] Figure 3Figure 1 shows a side section through the dryer 1. The fans 21, which extract the moisture-saturated drying air from the drums T1 and T2, are flanged to the heating and fan compartments 24 and connected to the auxiliary chambers 11 T1 and 11 T2 via connections or adapters (not shown). The drums T1 and T2 are also connected to the auxiliary chambers 11 T1 and 11 T2 via connections, positioned one above the other. The heating and fan compartments 24 are arranged as separate chambers in the area of ​​the rear end face of the dryer 1, with the auxiliary chambers 11 T1 and 11 T2 located between the heating and fan compartments 24 and the dryer compartments 2 T1 and 2 T2. The drives for the fans 21 are located outside the heating and fan compartment 24, while the fan impellers are located inside. One fan 21 is assigned to each drum T1 and T2. The fans 21 are connected via connections or...Adapters with the additional chambers 11 T1 , 11 T2 and these also connected via connections or adapters to the drying rooms 2 T1 , 2 T2.

[0037] The moisture-laden drying air flows from the drums T1, T2 into the auxiliary chambers 11 T1, 11 T2 and from the auxiliary chambers 11 T1, 11 T2 via connections into the intake cross-section of the respective fan 21. In the area of ​​the drums T1, T2, the exhaust air 14 T1, 14 T2 from the auxiliary chamber 11 T1, 11 T2 is extracted via a duct 15 T1, 15 T2, which is arranged on the front face (see Figure 1 and 2At the end of the duct, a fan (not shown) provides the necessary airflow. Fresh air is supplied to the drum T1, T2 area via the auxiliary chambers 11 T1, 11 T2, to which the duct 13 T1, 13 T2 is connected at the front. The mixture of fresh and drying air flows from the auxiliary chambers 11 T1, 11 T2 into the heating and fan chamber 24, as the fans 21 create a negative pressure in the drying chambers 2 T1, 2 T2 through extraction. This is a closed-loop system from which a partial mass flow in the form of exhaust air is extracted and a partial mass flow in the form of fresh air is supplied.

[0038] The additional chambers 11 T1, 11 T2 allow the drying air to expand, thus reducing its flow velocity many times over as it exits the drum T1, T2. Furthermore, the negative pressure in the additional chambers 11 T1, 11 T2 allows fresh air 12 T1, 12 T2 to be freely drawn in and supplied to the heating and fan chamber 24 with drying air.

[0039] Heating elements in the form of heat exchangers, one or more gas heaters or electric heaters can be arranged on or inside the heating and fan room 24, which heat the exhausted drying air including the fresh air 12 T1 , 12 T2 to the drying temperature.

[0040] Since the drying chambers 2T1 and 2T2 operate at significantly different temperature levels, and the lower drying chamber 2T1 is operated at least 60°C, preferably at least 90°C, warmer, its vertically radiating waste heat reduces the energy required for the upper drying chamber 2T1. The duct 13T1 for the fresh air 12T1 of the lower drum T1 is adjacent to the drying chamber 2T2 and the auxiliary chamber 11T2 of the upper drum T2, thus preheating the fresh air 12T1 for the lower drying chamber 2T1. This allows the drying air in the lower drying chamber 2T1 to absorb more moisture. The heating energy required for water evaporation is reduced. The exhaust air 14 T1 from the lower dryer chamber 2 T1 heats the side walls of the duct 15 T1, so that the air in the upper dryer chamber 2 T2 and in the upper auxiliary chamber 11 T2 is additionally heated via convection.The exhaust air 14 T1 and the fresh air 12 T1 for the lower drying chamber 2 T1 are routed through ducts 13 T1 and 15 T1, located between the upper auxiliary chamber 11 T2 and the upper drying chamber 2 T2. This preheats the fresh air 12 T1 for the lower drying chamber 2 T1, allowing it to absorb more moisture. The lower drying chamber requires less heating energy for the same evaporation output. The hot exhaust air 14 T1 and the waste heat from the lower drying chamber 2 T1 heat the upper auxiliary chamber 11 T2 and the upper drying chamber 2 T2. The dryer 1 can therefore be operated with higher energy efficiency. Reference sign

[0041] 1 Dryer 2 T1, 2 T2 Dryer chamber 3 T1, 3 T2 Air guide cylinder 4 T1, 4 T2 Screen cover 5 Fabric web 6 Inlet 7 Deflection roller 8.1, 8.2 Deflection roller 9 Outlet 10 Deflection roller 11 T1, 11 T2 Auxiliary chamber 12 T1, 12 T2 Fresh air 13 T1, 13 T2 Duct 14 T1, 14 T2 Exhaust air 15 T1, 15 T2 Duct 16 Passage opening 17 T1, 17 T2 Flow channel 18 T1, 18 T2 Vertical partition 19 Horizontal partition 21 Fan 23 Heating element 24 Heating and fan room T1, T2 drum

Claims

1. Dryer (1) for a textile web (5), comprising at least two vertically arranged drying chambers (2) T1 , 2 T2 ), where each drying room (2 T1 ; 2 T2 ) a drum (T1; T2) with flow channels arranged on both sides of it (17) T1 , 17 T2 ) has, and that each dryer room (2 T1 ; 2 T2 ) a separate additional chamber (11 T1 , 11 T2 ) has the channels (13 T1 , 13 T2 , 15 T1 , 15 T2 ) to supply fresh air (12 T1 , 12 T2 ) and exhaust air drainage (14 T1 , 14 T2 ) exhibits, with the additional chambers (11 T1 , 11 T2 ) between one end wall of the associated drying room (2 T1 ; 2 T2 ) and a separate heating and fan room (24), characterized by the fact that the channels (13 T1 , 15 T1 ) to supply fresh air (12 T1) and exhaust air drainage (14 T1 ) of the lower drying room (2 T1 ) in the upper drying room (2 T2 ) and at the upper accessory chamber (11 T2 ) issue.

2. Dryer according to claim 1, characterized by the fact that the flow channels (17 T1 , 17 T2 ) through perforated screen covers (4 T1 4 T2 ) are separated from the drums (T1, T2).

3. Dryer according to claim 1, characterized by the fact that the drums (T1, T2) air guide cylinders (3 T1 , 3 T2 ) which are preferably adjustable.

4. Dryer according to claim 1, characterized by the fact that the drying rooms (2 T1 ; 2 T2 ) except for a passage opening (16) for the passage of the goods web (5) are completely separated from each other.

5. Dryer according to claim 1, characterized by the fact that in the heating and fan rooms (24) fans (21) for extracting the exhaust air from the drying rooms (2 T1 ; 2 T2are arranged.

6. Dryer according to claim 1, characterized by the fact that within the heating and ventilation rooms (24) means for heating the drying air are arranged.

7. Dryer according to claim 6, characterized by the fact that The means for heating the drying air are designed as heat exchangers, gas burners or electric heaters.

8. Dryer according to claim 1, characterized by an inlet (6) for the web of material (5) to enter, two deflection rollers (8.1, 8.2) at a passage opening (16) for guiding the web of material (5) from the lower drum (T1) to the upper drum (T2), and an outlet (9) for removing the web of material from the dryer.

9. Method for drying a textile web (5), wherein in two vertically arranged drying chambers (2 T1 ; 2 T2) with each drum (T1; T2) a separate flow of heated drying air is directed, wherein the web (5) is first guided around the lower drum (T1), and then around the upper drum (T2), wherein the heated drying air flows through the web (5) and is discharged via an interior of the drums (T1, T2), wherein fresh air (12 T1 , 12 T2 ) for each drying room (2 T1 ; 2 T2 ) in an associated separate upper and lower auxiliary chamber (11 T1 , 11 T2 ) supplied and exhaust air (14 T1 , 14 T2 ) via the associated supplementary chamber (11 T1 , 11 T2 ) is discharged, whereby the fresh air (12 T1 , 12 T2 ) within the additional chambers (12 T1 , 12 T2 ) is mixed with the drying air, characterized by the fact that the fresh air (12 T1 ) for the lower drying room (2 T1 ) on the upper accessory chamber (11 T2) and the upper drying room (2 T2 ) is passed by and thus preheated.

10. Method for drying a textile web (5) according to claim 9, characterized by the fact that the exhaust air (14 T1 ) for the lower drying room (2 T1 ) on the upper accessory chamber (11 T2 ) and the upper drying room (2 T2 ) is led past.

11. Method for drying a textile web (5) according to claim 10, characterized by the fact that the lower drying room (2 T1 ) is operated at a temperature at least 30°, preferably at least 60°, particularly preferably at least 90°, higher than the upper drying chamber (2 T2 ).

12. Method for drying a textile web (5) according to claim 9, characterized by the fact that the heated drying air before flowing through the drums (T1, T2) along a flow channel (17) T1 , 17 T2 ) guided and using perforated screen covers (4 T1 4 T2) is homogenized in terms of flow velocity.

13. Method for drying a textile web (5) according to claim 9, characterized by the fact that the drying intensity of the web (5) across the working width by air guide cylinders (3 T1 , 3 T2 ) is set within the drums (T1, T2).

14. Method for drying a textile web (5) according to claim 9, characterized by the fact that the web of goods (5) wraps around each drum (T1, T2) by at least 280°.

15. Method for drying a textile web according to claim 9, characterized by the fact that within the additional chamber (11 T1 , 11 T2 ) the exhaust air (14 T1 , 14 T2 ) is removed from the drying air at the point where it has the lowest temperature or energy level.

16. Method for drying a textile web according to claim 9, characterized by the fact that the fresh air (12 T1 , 12 T2) and the drying air within the respective heating and fan room (24) is heated.

17. Method for drying a textile web according to claim 16, characterized by the fact that the warming of the fresh air (12 T1 , 12 T2 ) and drying air via heat exchangers, gas burners and / or an electric heater.

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