GB2111660A

GB2111660A - Drying webs

Info

Publication number: GB2111660A
Application number: GB08230684A
Authority: GB
Inventors: Karl-Heinz Gottschalk; Gunter Haupt
Original assignee: Babcock Textilmaschinen GmbH
Current assignee: Babcock Textilmaschinen GmbH
Priority date: 1981-11-12
Filing date: 1982-10-27
Publication date: 1983-07-06
Also published as: ES8403602A1; IT8224181A0; ES517287A0; NL8204252A; GB2111660B; IT1154557B; FR2516224A1; DE3144923A1; FR2516224B1

Abstract

Gaseous or vaporous treatment agent is repeatedly blown on to and again drawn off from a travelling run of cloth after each operation in the heat treatment especially the drying, of the run of cloth, and the gaseous or vaporous streams of treatment agent are directed in counterflow to the direction of travel of the run of cloth during the entire treatment or parts of the entire treatment in such a way that the treatment agent, drawn off from the run of cloth after the treatment action in zones of treatment downstream, is returned in whole or in part into zones of treatment further upstream, there again blown onto the run of cloth, and only thereafter abstracted from the overall treatment. In apparatus for carrying out the method, a plurality of nozzles are arranged above and/or below the run of cloth (10) in a treatment chamber (11) with an intake opening (17) and a discharge opening (18) for the run of cloth, and spaced are provided between the nozzles for flow of treatment agent drawn off from the cloth, and the supplying of fresh treatment agent to the nozzles with reference to the direction of travel of the run of cloth through the treatment chamber takes place in downstream zones of the treatment and the exhaustion of spent treatment agent from the treatment chamber takes place in treatment zones further upstream. The nozzles may be arranged in groups, or combined in nozzle housings (12). <IMAGE>

Description

SPECIFICATION Method of and apparatus for heat treatment of travelling runs of cloth This invention relates to a method for the heat treatment, especially for the drying, of travelling runs of cloth, wherein, in the course of the overall duration of the treatment, gaseous or vaporous treatment agent is repeatedly blown on to the run of cloth and again drawn off from the run of cloth after each treatment operation, as well as to an apparatus for carrying out the method in which a plurality of noules, preferably combined in nozzle housings, are arranged above and/or below the run of cloth in a treatment chamber with an intake opening and a discharge opening for the run of cloth, and spaces are provided between the nozzles for flow of treatment agent drawn off from the cloth.

Heat-treatment appliances have an extremely high energy consumption, owing particular to the heating up of the treatment agent required for the treatment.

It has now been demonstrated that, in the drying of travelling runs of cloth, in the case of which the treatment agent, for example air, is essentially circulated across radiators and in the course of which during the entire treatment in all treatment zones a portion of the air is continually discharged from the treatment as spent air and is replaced by fresh air to be heated up a new, the efficient utilization of the energy supplied is not optimal, as the spent air is discharged without due regard for the moisture taken up from the run of cloth. The moisture concentration in the spent air becomes smaller and smaller with progressive drying treatment, from which it follows that heat energy not expoited to the full is discharged directly in the downstream treatment zones.

In order to recover this energy, it has already been proposed to provide special heat exchangers in which a part of the heat from the spent air is again supplied to the fresh air in order to preheat this air.

The expenditure pertaining to such a heat exchanger is, of course, considerable and makes the heat-treating apparatuses much more expensive.

The present invention is based upon the consideration that the treatment agent drawn off from downstream zones of a drying treatment has taken up only small amounts of moisture and would be in a condition readily to take up additional moisture, which, however, is no longer at all available in the downstream zones. Hence it follows that the problem posed for the present invention is the reduction of the energy consumption, especially in the case of driers, through improved utilization of the energy contained in the spent air particularly from downstream treatment zones with the object of increasing the evaporative performance and consequently of improving the efficiency of the drier.

For the solution of this problem and in accordance with the present invention, we provide a method for the heat treatment, especially the drying, of travelling runs of cloth, wherein, in the course of the overall duration of the treatment, gaseous or vaporous treatment agent is repeatedly blown on to the run of cloth and again drawn off from the run of cloth after each treatment operation, and the gaseous or vaporous streams of treatment agent are directed in counterflowto the direction of travel of the run of cloth during the entire treatment or parts of the entire treatment in such a way that treatment agent, drawn off from the run of cloth after the treatment action in zones of treatment downstream, is returned in whole or in part into zones of treatment further upstream, there again blown onto the run of cloth, and only thereafter abstracted from the overall treatment. Thus, in application of the method according to the invention in drier operating with air, the air is directed in counterflowto the direction of travel of the run of cloth. Thus, the return of treatment agent from downstream zones into treatment zones further upstream can be undertaken repeatedly and successively prior to the abstraction of the treatment agent from the overall treatment, and consequently a directing of the air or other treatment agent purely in counterflow can be undertaken throughout the entire treatment. Moreover, a plurality of treatment zones may be combined on the return of treatment agent from treatment zones further downstream into treatment zones further upstream.

Furthermore, it is also within the scope of the invention to provide that the abstraction of treatment agent from the overall treatment is at least prior to the final supplying of treatment agent to the run of cloth in the direction of travel of the run of cloth during the overall treatment. Moreover, the abstraction of treatment agent from the overall treatment may take place in about the first third of the overall treatment, whereas the supplying of fresh treatment agent to the run of cloth is undertaken evenly distributed during the overall treatment.

Also in accordance with the present invention, we provide apparatus for carrying out the method in accordance with the invention, in which apparatus a plurality of nozzles are arranged above andlor below the run of cloth in a treatment chamber with an intake opening and a discharge opening for the run of cloth, and spaces are provided between the nozzles for flow of treatment agent drawn off from the cloth, and the supplying of fresh treatment agent to the nozzles with reference to the direction of travel of the run of cloth through the treatment chamber takes place in downstream zones of the treatment and the exhaustion of spent treatment agent from the treatment chamber takes place in treatment zones further upstream.

The nozzles may be arranged in groups or combined in nozzle housings. Moreover repeated blowing of the treatment agent on to the run of cloth with subsequent exhaustion from the run of cloth and return to preceding nozzles, groups of nozzles, or nozzle housings may be undertaken between the supplying and exhaustion of the treatment agent.

The nozzles, groups of nozzles or nozzle housings may also be combined to form treatment zones in which fresh treatment agent is supplied to each nozzle, each group of nozzles, or each nozzle housing, and the treatment agent exhausted from the run of cloth in an entire zone is supplied combined to nozzles, groups of nozzles or nozzle housings further upstream and likewise combined in treatment zones, and, after being again blown on to the run of cloth, is abstracted therefrom out of the treatment chamber.

In the case of heat-treatment equipment of the so-called counter type of construction, in which adjacent treatment zones, through fans arranged alternately at opposite sides of the treatment chamber and not only introducing fresh treatment agent from outside into the treatment but also bringing about a further circulation of treatment agent out from and into adjacent zones, the abstraction ofthe spent treatment agent from the treatment chamber is to take place in aboutthe upstream third of the treatment chamber.

Moreover, it is also within the scope of the invention to provide that treatment agent taken off from downstream regions of the treatmentis supplied to regions further upstream in the treatment for the direct preheating of the treatment agent freshly supplied there.

Furthermore, the treatment agent abstracted from the treatment chamber may serve for preheating freshly supplied treatment agent, heat exchangers being provided for the transfer of heat.

The invention will be explained hereinafter in more detail with reference to the accompanying drawings. In the drawings: Fig. 1 shows a basic representation of the counterflow principle; Fig. 2 shows a complete directing in counterflow according to the invention; Fig. 3 shows such a counterflow directing in another view towards a drier; Fig. 4 shows a counterflow directing according to the invention in sections; Fig. 5 shows the same counterflow directing in a side view towards a drier; Fig. 6 shows the directing of spent air according to the invention in a counter-type drier; and Fig. 7 shows preheating of fresh air by spent air by means of a heat exchanger.

Like parts are provided with like reference numerals throughout the drawings.

In Fig. 1 there is represented the principle of directing of a run of cloth (10) and treatment agent in counterflow through a treatment chamber (11). This principle is proven with other heat-treating procedures, for example in the drying of wood or the like.

In the case of the latter procedure, the intensiveness of the treatment is, of course, low, as the treatment agent merely passes over the commodity to be treated.

The circumstances are different with the invention which refers to the intensive blowing of the treatment agent on to a travelling run of cloth, in order to ensure that the treatment is speedily accomplished in short courses of treatment Such a complete counterFlow directing, in which the fresh air is introduced by means of a fan (16) through a fresh-air connection (17) over a radiator (20) into a nozzle housing (12) in a treatment chamber (11), is shown in Fig. 2.As is indicated by arrows, the treatment agent, flowing off from the run of cloth (10) after the treatment, is supplied to an upstream nozzle housing (12) and there again blown on to the run of cloth and so on, up to the beginning of the treatment, where it is drawn off by means of a fan (16) and is abstracted from the treatment through the exhaust-air connection (18). As shown in Fig. 2, further fans (16) and radiators (20) may be interposed in the path of flow of the treatment agent in order to support the flow of the treatment agent and for further heating of same.

The directing of treatment agent in Fig. 3 corresponds to that of Fig. 2. This representation shows a drier in which the fans (16) and radiators (20) are arranged alternately at the two sides of the treatment chamber. In the Fig. 3 embodiment there is also a complete directing in counterflow of the treatment agent from the emergence of the run of cloth (10) from the chamber to the entry thereof into the chamber.

The circumstances are different in the case of the representation in Fig. 4, wherein the treatment chamber (11) is sub-divided into two zones, there could, of course, also be more than two zones-, fresh treatment agent being supplied to all nozzle housings (12) in the rearward zone (13) and this treatment agent after the treatment being supplied to the noule housings of the forward zone (14) for renewed treatment before it is abstracted from the treatment chamber through the exhaust-air connection (18). A similar directing of treatment agent is represented in Fig. 5 in a different view.

Manifestly, there may be carried out many variants in the directing of treatment agent, which are all within the scope of the invention, that is treatment agent taken from zones of treatment downstream is first to be supplied to zones of treatment further upstream to carry out a further treatment action before being finally abstracted from the treatment.

Thus a so-called counter-type drier (15), such as is represented in Fig. 6 is also within the scope of the invention, the exhaust air connection (18) being arranged in about the first third of the treatment chamber (11) of the drier (15). As there is no abstraction of the spent air in the rear part of the chamber, the treatment agent must flow to the exhaust air connection through the return air guidance indicated by arrows in a direction opposite to that of travel of the run of cloth (10), whereby the effect in accordance with the invention is then also achieved.

Fig. 7 further shows the additional recovery of energy from the spent air and transfer of same to the fresh air by means of a heat exchanger (19). In this Fig. the reference numeral (21) denotes, moreover, the disposition of a moisture measuring and recording instrument. As there is only one outlet position for the spent air, only a single one of these expensive instruments is required.

Claims

1. A method for the heattreatment, especially the drying, oftravelling runs of cloth, wherein, in the course of the overall duration ofthe treatment, gaseous or vaporous treatment agent is repeatedly blown on to the run of cloth and again drawn off from the run of doth after each treatment operation, and the gaseous or vaporous streams of treatment agent are directed in counterflow to the direction of travel of the run of cloth during the entiretreatment of parts ofthe entire treatment in such a waythatthe treatment agent, drawn off from the run of o)oth after the treatment action in zones of treatment downsteam, is returned in whole or in part into zones of treatment further upstream, there again blown onto the run of cloth, and only thereafter abstracted from the overall treatment

2. A method according to claim 1, in which the return oftreatmentagentfrom treatmentzones further downstream into treatment zones further upstream is undertaken again and again successive- ly prior to the abstraction ofthetreatmentagent from the overall treatment

3. A method aocording to claim 1 or2, in which a pluralityoftreatmentzonesare combined on the return of treatment agent from treatment zones further downstream into treatment zones further upstream,

4. A method according to claim 1,2 or Bin which the abstraction of treatment agent from the overall treatment is at least prior to the final supplying of treatment agent to the run of cloth in the direction of travel of the run of cloth during the overall treat menL

5.A method according to any one of claims 1 to 4, in which the abstraction of treatment from The overall treatrnent takes place in aboutthefirstthird ofthe overall treatment, whereas the supplying of fresh treatment agent to the run of cloth is undertaken evently distributed during the overall treatment

6.Apparatus forcarry.ing out the method according to any one of claims 1 to 5, in which a plurality of nozzles are arranged above and'our below the run of cloth in a treatment chamber with an intake opening and a discharge opening for the run of cloth, and spaces are provided between the nozzles for flow of treatment agent drawn off from the cloth, and the supplying of fresh treatment agent to the nozzles with ref & nceto the direction of travel of the run of cloth through the treatment chambertkes place jn downstream zones of the treatment and the exhaustion of spent treatment agentfrom the treatment chamber takes place in treatment zones further upstream.

7 Apparatus according to claim 6, in which nozzles are arranged in groups.

8. Apparatus according to claim 6, in which nozzles are combined in nozzle housings.

S. Apparatus according to claim 6, 7 or 8, in which repeated blowing of the treatment agent on to the run of cloth with subsequent exhaustion from the run of cloth and return to preceding nozzles, groups of nozzles, or nozzle housings is undertaken between the supplying and exhaustion of the treat snent agent.

10. pparatus according to daìm 9 in which the nozzles groups of nozzles or nozzle housings in the treatment chambers are com- bined tDSorm treatrnentzones in which fresh treatment agent is supplied to each nozzle, each group of nozzles, or each nozzle housing and the treatment agent exhausted from the run of cloth in an entire zone is supplied combined to nozzles, groups of nozzles or nozzle housings further upstream and likewise cornbned in treatment zones and, after being again blown on to the run of cloth, is abstracted therefrom out ofthe treatmen-t chamber.

11. Apparatus according to claim liD, in which the heat-treatment equipment 5 of the so-called counter type of construction, in which adjacent treatment zones, through fans arranged alternately at opposite sidesofthe treatment chamber and not only intro ducking fresh treatment agentfrorn outside into the treatment but also bringing about a further circulation of treatmentagent out from and into adjacent zones and the abstraction of the spent treatment agent from the treatment chamber takes place in about the upstream third of the treatment chamber.

12 Apparatus according to claim 10 or 11, in which treatmentagenttal:en off from downstream zones of the treatment is supplied to regions further upstream in the treatment for the direct preheating ofthe treatment agent freshly supplied there.

13. Apparatus according to any one of claims stro 111, in which the treatment agent abstracted from the treatrnentchamberserves for preheating freshly supplied treatment agent, heat exchangers being providedforthe transfer of heat.

14. A method for the heat treatment, especially the drying, of travelling runs of cloth, substantially as hereinbefore described with reference to the accompanying drawings.

15. Apparatus for the heat treatment especially the drying, of travelling runs of cloth, substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

16. Apparatus for the heat treatment especially the drying, of travelling runs of cloth, substantially as hereinbefore described with reference to Fig. 3 of the accompanying drawings.

17. Apparatus for the heai treatment, especially the drying, of travelling runs of cloth, substantially as hereinbefore described with reference to Fig. 4 of the accompanying drawings.

18. Apparatus for the heat treatment, especlally the during, of travelling runs of cloth, substantially as hereinbefore described with reference to Fig. 5 of the accompanying drawings.

19. Apparatus forthe heat treatment, especially the drying, cftraveiling runs of cloth, substantially as hereinbefore described with reference to Fig. 6 of the accompanying drawings.

20. Apparatus for the heat treatment, especially the drying, of travelling runs of cloth, substantially as hereinbefore described with reference to Fig. 7 of the accompanying drawings.