Device for heat treatment of a web of goods

Abstract

Device for heat-treating a web of material (1) comprising a plurality of at least two fields (2), each of the fields (2) having at least one circulating air blower (6) for circulating treatment gas and means for heating (7) the treatment gas, nozzle boxes (9) for blowing the treatment gas onto the web of material (1), means for transporting the web of material (1) through the device, an inlet slot (3) and an outlet slot (4) for the web of material (1), means for discharging exhaust air from the device and means for supplying preheated fresh air into the device, characterized in that a fresh air duct (11) for distributing the fresh air directly into intake areas of at least one part of the fields (2) is arranged, wherein at least one part of the fields (2) is assigned an inlet air damper (13) and an exhaust air damper (16).

Description

[0001] The invention relates to a device for heat-treating a web of material, comprising a plurality of at least two fields, each of which has a blower for circulating treatment gas and means for heating the treatment gas, nozzles for blowing the treatment gas onto the web of material, means for transporting the web of material through the device, an inlet slot and an outlet slot for the web of material, means for removing exhaust air from the device and means for supplying preheated fresh air into the device.

[0002] Such devices are known per se and are described, for example, in DE 103 33 483 A1. They are used, for example, to refine and / or dry the web. If necessary, the web is treated with a finishing agent before heat treatment.

[0003] A device designed as a tension frame has a substantially enclosed housing divided into several compartments. The web of material is guided through the device in a largely horizontal plane by means of a transport device.

[0004] From EP 0 132 498 B1, a method for drying moving webs of material in a recirculating air dryer is known, in which fresh air is supplied to a front part of the dryer and exhaust air is extracted from a rear part. The fresh air supply can be through an inlet slot for the web, and the exhaust air can be extracted in the last dryer compartment or before it. It is also described to preheat the fresh air directly or indirectly using the exhaust air. This is intended to reduce the temperature difference between the supplied fresh air and the treatment air in the treatment chambers.

[0005] In known devices, the fresh air, which may be preheated, is fed directly into the nozzles for blowing the treatment gas, together with the recirculated air, without ducts. This can cause some of the fresh air to bypass the exhaust air, resulting in the fields being cooled by the fresh air. This is energy-inefficient and carries the risk of unwanted condensation.

[0006] CN 101 619 923 A describes a dryer in which, to increase performance, a pressure line of a recirculating air system is arranged above a conveying device for dry goods. Cold fresh air, along with recirculated air, is fed via a heating device into the suction side of a recirculating air blower. The dryer is not suitable for processing webs of fabric.

[0007] Further state of the art is represented by the publications DE 100 10 842 A1, DE 73 07 613 U, DD 222 102 A1, DE 83 32 567 U1, DE 196 23 303 A1 and DE 10 2012 109 878 A1.

[0008] The object of the invention is to create a device for heat-treating a web of material in which energy is used very efficiently and at the same time condensation within the device is avoided.

[0009] The problem is solved by the features of claim 1. Fresh air ducts for distributing fresh air directly in the intake areas of at least some of the fields are arranged, wherein at least some of the fields are assigned an exhaust air damper and a supply air damper. The intake area of ​​a field is defined as the area through which the treatment gas flows after leaving the nozzle boxes; in particular, the suction chamber is included in the intake area. By distributing the fresh air in the intake area, the treatment temperature in the fields can be better controlled because a uniform temperature of the treatment gas is present at the nozzles instead of a mixture of recirculated and fresh air. This uniform temperature is easy to measure and therefore also easy to control. This improves the quality of the treated web.The arrangement of the exhaust and supply air dampers allows for reliable adjustment of the exhaust air volume for each individual section according to requirements. For example, a higher exhaust air volume can be set in the front sections, corresponding to the evaporation rate, than in the rear sections, where evaporation is minimal and the treatment temperature is more critical. The fresh air volume can be adjusted for each section to maintain only a slight negative pressure within the entire unit relative to the outside atmosphere, thus significantly reducing the ingress of cold ambient air through the slots. This also reduces the unit's energy consumption by decreasing the exhaust air volume and improves the quality of the finished web.

[0010] Fresh air within the meaning of this invention can also be gas from another process that is air-like without harmful components and without significant moisture. The gas may be heated.

[0011] The dependent claims relate to the advantageous embodiment of the invention.

[0012] In one embodiment, the fresh air ducts are essentially routed within the device. This minimizes condensation problems.

[0013] In a further embodiment, the fresh air is guided within dedicated channels above and below the web in the area of ​​the inlet and outlet slots. This reduces the unwanted ingress of cold ambient air through the inlet and outlet slots into the treatment zones of the device, as the ambient air temperature is increased by radiant heat. The fresh air channels are largely located within the device, thus preheating the fresh air. Therefore, the risk of condensation on the fresh air channels and in zones of the device adjacent to the slots is minimized.

[0014] In a further embodiment, each of the channels has at least a series of nozzle holes or slots directed towards the web. This creates an air curtain that greatly reduces the ingress of ambient air through the slots, thus enhancing the aforementioned advantages.

[0015] In a further embodiment, the fresh air is ultimately distributed to the suction chambers of the fields. This results in a homogeneous treatment gas due to heating, mixing with the recirculated air, and thus improving the quality of the treated web. Furthermore, this increases throughput and reduces the exhaust air volume. The treatment chamber maintains a uniform temperature, minimizing the risk of condensation.

[0016] In another embodiment, the fresh air is heated in at least one heat exchanger using the exhaust air. This reduces energy consumption.

[0017] In a further embodiment, two heat exchangers are arranged, with a first one located in the area of ​​the first of the fields and a second one located in the area of ​​the last of the fields. This improves the airflow.

[0018] The invention is further explained with reference to the schematic drawing. It shows Fig. 1 a vertical longitudinal section through a device for heat-treating a web of material, Fig. 2 a horizontal longitudinal section through the device of the Fig. 1 and Fig. 3 a vertical cross-section through the device.

[0019] Flows within the device are indicated by thin arrows.

[0020] As from the Fig.As shown in Figures 1 to 3, a device for heat-treating a web of material 1 comprises a plurality of six sections 2 arranged in a row, forming a largely enclosed housing. The sections 2 are separated from each other by partitions, each with a slot for the passage of the web of material 1. The device has an inlet side (shown here on the left) with an inlet slot 3 for the web of material 1 and an outlet side (shown here on the right) with an outlet slot 4.

[0021] Furthermore, means for transporting the web 1 through the device are arranged. These means comprise two endless, driveable transport chains, the transport sections of which are mounted spaced apart in a horizontal plane and form a transport plane for the web 1. Clamps are attached to the transport chains, in which edges of the web 1 can be secured, so that the web 1 can be guided through the device in the intended transport direction according to arrow 5.

[0022] Each of the fields 2 has a recirculating air blower 6 and a heating device 7, which are arranged below a level in which the web 1 is transported. A suction chamber 8 is formed below this level, in which at least parts of the heating device 7, such as a distribution pipe for heated treatment gas, are mounted. A suction side of the recirculating air blower 6 is connected to the suction chamber 8. A pressure side of the recirculating air blower 6 is connected to nozzle boxes 9, which are arranged above and below the aforementioned level and, during operation, blow the treatment gas onto the web 1. A significant portion of the blown treatment gas, which is recirculated, returns to the suction chamber 8, where it is reheated and drawn in by the recirculating air blower 6. Alternatively, two recirculating air blowers 6 are arranged, one being assigned to the upper nozzle boxes 9 and the other to the lower nozzle boxes 6.

[0023] In order for the heat treatment to be carried out effectively in the device, a portion of the treatment gas must be continuously extracted as exhaust gas and fresh air supplied accordingly. For this purpose, an exhaust air duct 10 and a fresh air duct 11 are provided. To utilize the energy present in the exhaust air, waste heat recovery is also provided by means of two air-to-air heat exchangers 12.

[0024] The fresh air duct 11 extends above all suction chambers 8 and is connected to the corresponding suction chamber 8 for a portion of the bays 2 – specifically, the second and third bays 2 – via an air inlet damper 13. The fresh air duct 11 is routed such that it runs within the area of ​​the suction chambers 8 and is divided into channels on both the inlet and outlet sides within the device. It is routed above and below the transport level and outside the adjacent bay 2 with an opening for the web 1. Nozzle holes 17 or slots directed towards the web 1 are integrated into these channels of the fresh air duct 11. On each of the aforementioned sides, the fresh air duct 11 then runs for a predetermined length above the nozzle boxes 9 and continues outwards on the device, where the associated heat exchanger 12 and a fresh air blower 14 are integrated.

[0025] The exhaust air duct 10 also extends above all suction chambers 8. On the inlet side, the exhaust air duct 10 is routed outside the device into the associated heat exchanger 12. An exhaust air fan 15 is arranged to convey the exhaust air. On the outlet side, the exhaust air duct 10 is routed accordingly and equipped with the associated components. To allow the exhaust air volume to be controlled separately for each of the compartments 2, an exhaust air damper 16 is assigned to the pressure chamber of at least some of the compartments of compartments 2 (corresponding to the fresh air dampers 13).

[0026] During operation, the edges of the web 1 are secured in the clamps, and the web 1 is transported successively through the individual sections 2 and thus through the device in the transport direction 5. Depending on the type of treatment, the web 1 is either tensioned or unstrapped.

[0027] In the device, the web 1 is treated with the treatment gas, usually heated air. For this purpose, the treatment gas is heated to a predetermined temperature in each of the compartments 2 separately by means of the heating device 7 and circulated by the recirculating air blower 6. The recirculated air is directed from the pressure side of the recirculating air blower 6 into the nozzle boxes 9 and then onto the web 1; the recirculated air then enters the suction chamber 8, is heated there, and then flows into the suction side of the recirculating air blower 6 to be compressed and conveyed back to the pressure side. In the device, for example, water and / or solvents are evaporated and applied finishing agents are fixed. The temperature and the recirculated air volume can be set and regulated differently for each of the compartments 2.

[0028] To prevent the recirculated air from becoming saturated with water and / or solvent, exhaust air is extracted from each of the two fields via the exhaust air damper 16 and the exhaust air duct 10. The exhaust air volume can vary from one of the two fields to another to accommodate the evaporation rate of the water and / or solvent. This optimizes the treatment process and saves energy, for example, by reducing the overall exhaust air volume. Depending on the exhaust air volume, preheated fresh air is supplied to each of the two fields via the fresh air duct 11 and the supply air damper 13, and then into the suction chamber 8. This allows the negative pressure within the device relative to the ambient atmosphere to be kept very low. The fresh air is supplied by the fresh air blower 14 and preheated by the exhaust air in the heat exchanger 12.In the inlet and outlet areas, a small portion of fresh air from the fresh air duct 11 exits through the nozzle holes 17. This fresh air is directed towards the web 1, forming air curtains that at least reduce the ingress of (relatively cold) ambient air through the inlet slot 3 and the outlet slot 4, respectively. This prevents condensation from forming in the device. Reference symbol list 1 freight train 2 Field 3 inlet slots 4 outlet slots 5 Arrow 6 recirculating air fans 7 Heating device 8 Suction chamber 9 nozzle boxes 10 Exhaust duct 11 Fresh air duct 12 heat exchangers 13 Air intake flap 14 fresh air blowers 15 exhaust fans 16 Exhaust flap 17 nozzle holes

Claims

[1] Device for heat-treating a web of material (1) comprising a plurality of at least two sections (2), each of the sections (2) comprising at least one circulating air blower (6) for circulating treatment gas and means for heating (7) the treatment gas, nozzle boxes (9) for blowing the treatment gas onto the web of material (1), means for transporting the web of material (1) through the device, an inlet slot (3) and an outlet slot (4) for the web of material (1), means for extracting exhaust air from the device and means for supplying preheated fresh air into the device, characterized by , that a fresh air duct (11) for distributing the fresh air directly into intake areas of at least one part of the fields (2) is arranged, wherein at least one part of the fields (2) is assigned a supply air damper (13) and an exhaust air damper (16). [2] Device according to claim 1, characterized bythat the fresh air ducts (11) are essentially routed within the device. [3] Device according to claim 1 or 2, characterized by , that the fresh air in the area of ​​the inlet slot (3) and the outlet slot (4) is guided within the associated fresh air ducts (11) above and below the web of goods (1). [4] Device according to claim 3, characterized by that each of the fresh air ducts (11) has at least one series of nozzle holes (17) or slots directed towards the web (1). [5] Device according to any one of claims 1 to 3, characterized by , that the fresh air is heated in at least one heat exchanger (12) by means of the exhaust air. [6] Device according to any one of claims 1 to 4, characterized by , that two of the heat exchangers (12) are arranged, wherein a first one is located in the area of ​​a first of the fields (2) and a second one is located in the area of ​​a last of the fields (2).

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