DE10047834A1 - textile machine - Google Patents

Abstract

The invention relates to a heat exchanger for heating the ambient air of a textile machine, preferably a tenter frame, comprising a heat exchanger channel (20) for guiding through the ambient air. Said heat exchanger channel (20) is to be configured in such a way as to heat an air stream (21) that is drawn through by suction uniformly throughout the flow cross-section. According to the invention, a gas-heated heat exchanger is provided with at least two flame tubes (26, 27) which extend spatially parallel to each other and next to each other inside the heat exchanger channel (20). Heating agents flow through adjacent flame tube in opposite directions.

Description

The invention relates to a textile machine, preferably a tenter frame, with circulating air heating with the help of at least one heat exchanger, which one to pass through direct the heat exchanger duct serving the recirculating air with duct inlet and outlet how be channel walls extending from the channel entrance to the channel exit sitting.

The convection heating is intended for convection drying and / or fixing machines NEN for thermal treatment of a textile fabric. Examples of such machines NEN are stenter frames and hotflues (cf. the corresponding keywords in Koch, Satlow, Large Textile Encyclopedia, German Publishing House Stuttgart, 1966). Also devices for the continuous shrinking treatment of textile webs according to DE-PS 92 79 74 and machines for drying thread sheets or be Layered carpets, according to DE-US 27 54 438, belong to the field of application the invention.

Such a machine is specified in EP-0 471 162 B2. This machine is in front seen for thermal treatment of a wide textile fabric with a treatment gas. The machine has nozzle boxes, the top and bottom half of the fabric are arranged across its width, parallel to Have fabric panels that extend across the panel and each have a fan Treatment gas are applied. The treatment gas becomes the suction side of the Fans fed through a heat exchanger. Each of the two fans is  mounted in a pressure box upstream of the respective nozzle box, such that independent control of pressure and especially temperature of the treatment gas in the lower and upper nozzle box is possible.

If a separate control of pressure or temperature of the two nozzle boxes Most is not essential, the textile machine according to DE-PS 36 27 904 also with a single fan, one for the bottom and upper nozzle box pressurized common pressure chamber. In a similar way With a hot flue, i.e. a loop dryer, temperature and Pressure controls on the various supply lines of the treatment agent be seen or not.

Means for heating are almost always used within the textile machines described the treatment air provided. The latter is mostly used as circulating air in the Cycle. Therefore, in the following, even if from the fan to part or only fresh air is drawn in, referred to as circulating air.

In conventional textile machines of the aforementioned type are pre-heated Combustion gases are immediately admixed to the circulating air, then one speaks from direct heating. The generally by burning gas or oil generated combustion gases contain substances, e.g. B. nitrogen oxides at a Row of synthetic fibers can lead to yellowing or color changes. the This effect also occurs especially with elastomer fibers (Lycra). This stretchy Fa stars are heavily rotated. In order to maintain the elasticity of these fibers, treated them with spinning oils. The spinning oils may be residue de the combustion gases discolored.

To counter this problem, are described in the textile machines indirect heating is also provided. Here are heat exchangers with oil run or steam heating used. These heat exchangers ensure that the Treatment agent flow, its volume and also its cross section - determines through the consumption in the nozzle system to be supplied - is relatively large, everywhere in the Flow cross section receives the same temperature. The latter is a requirement  for the fact that the flow of treatment agent emanating from the nozzle boxes is everywhere has the same temperature on the treated surface of the textile fabric. the However, this advantage is bought at a high price if the user uses heating systems to operate heat exchangers heated by oil circulation or steam are missing, i.e. considerable additional investments are required even if only now and then Use cases occur, e.g. B. when treating elastomeric fibers adverse yellowing or discoloration must be avoided.

There are also heat exchangers that work directly through a conventional gas burner is used in the textile machines with direct heating described above, are to be operated. A gas heated heat exchanger could in principle be like a Flame tube boilers are formed. If necessary, the Um to be heated air outside through the inside heated by a heating medium or heating gas Flame tubes of the heat exchanger directed. In this way, the circulating air can be heated sufficiently, the same temperature everywhere on the cross-section With existing heat exchangers, the circulating air flow can be z. B. without downstream mixer, do not guarantee. One for its funding The optimally trained fan practically mixes the conveyed air not at all. Cooler and warmer strands of air coming from the heat exchanger or flow lines leave the fan - accelerated - essentially as they were sucked in.

An uneven temperature distribution on the cross section of the circulating air flow can lead to the fact that the fabric treated in the textile machine on its surface is treated unevenly in accordance with these temperature differences. Out For this reason, when using a conventional gas-heated heat rope The heated circulating air must be mixed separately before handling it delenden textile web is brought into contact. Such mixers are on manoeuvrable.

The invention has for its object a textile machine, preferably one Tensioning frame to create with indirect gas heating, which without separate Mi is able to maintain a temperature or  provide heated air flow for treating the textile fabric. With in other words, a gas-heated heat exchanger should be used, wel cher a sucked air flow everywhere on its flow cross-section heated to the same temperature.

The solution according to the invention is for the textile machine of the type mentioned described in the characterizing part of claim 1. According to the invention gas-heated heat exchanger with at least two spatially parallel next to each other other within the heat exchanger channel, preferably in the form of pipe loops, extending flame tubes through which the heating medium can flow. Adjacent flame tubes become antiparallel, i.e. in opposite directions Direction through which the heating medium flows. Some improvements and further changes Events of the invention are specified in the subclaims.

According to the invention, a gas-heated, cocurrent, countercurrent is preferred and / or cross-flow operated heat exchanger with at least two space Lich parallel side by side within the heat exchanger channel, especially in Form of meandering pipe loops, extending flame pipes provided. The The term "direct current" heat exchanger means that the heating medium (within the Flame tubes) flows through the heat exchanger in the same direction as the Um air (outside the flame tubes). The heating medium inlet is therefore on Entrance of the heat exchanger duct, the heating medium outlet is at the duct outlet. "Counterflow" means that heating medium and circulating air in the opposite direction flow through the heat exchanger. With "cross flow", heating medium and circulating air flow across from each other. The invention also includes that adjacent flame tubes anti parallel, that is, in opposite directions, flows through the heating gas become.

At its core, the invention generally also consists of starting the flame tubes in this way arrange and train that the sum of the on each line parallel to the air circulation flow from flame tube to flame tube measured temperature values everywhere in the Cross section of the heat exchanger duct (perpendicular to the circulating air flow) is equal to. As a result, the circulating air at the heat exchanger duct outlet should be everywhere  the channel cross-section (perpendicular to the direction of flow) practically the have the same temperature. This homogeneously tempered gas stream can be accelerates with a fan - directly via the associated nozzle box be blown onto the fabric. A mixer or the like is not required Lich.

The flame tubes should preferably be in shape within the heat exchanger channel of pipe loops, especially as meandering loops. For the Success desired according to the invention may be advantageous if the Length of the duct wall to duct wall, i.e. across the air flow direction tion, extending pipe loop parts (the flame tubes) large against the length of the the opposite pipe longitudinal walls kungen is. The latter can also be outside of the duct air touched by the circulating air lumens lie. Preferably the longer ones should be transverse to the circulating air flow direction extending flame tube parts be substantially straight. If the The main part of the flame tubes lies transversely to the flow of the circulating air Cross-flow heater or speak of a cross-flow type heat exchanger. This can occur if the heating medium and circulating air are in the same or opposite direction flow to the channel input to the channel output (or vice versa), as equal current / cross-flow or counter-current / cross-flow heaters.

The circulating air is intended on its way through the heat exchanger duct according to the invention on most of the flow cross-section, preferably across the flow direction of the heating pipe parts. The goal of one everywhere the same heating of the circulating air flow cross section is particularly successful set if an even number of flame tubes, with pairs antiparallel Flame tubes to be flowed through by the heating means is provided. Straight Number or the arrangement in pairs is more important than with a small number of flame tubes when using many flame tubes. With an increasing number of pipes the relative contribution of the individual pipe to the convection heating is getting smaller. despite this can generally be said of a "heat exchanger with antiparallel in pairs flowed through flame tubes ".  

The temperature of each flame tube increases in the direction of flow of the heater tels - usually exponentially - but if two flame tubes are spatially parallel to each other arranged differently and in the opposite direction, ie antiparallel, from the Heating medium flows through, the heating effect of the two pipe parts is complementary with sufficient accuracy in practice so that between the tubes air flowing through is heated up everywhere in the duct cross-section.

If - especially with the cross-flow type heat exchanger - a pair of pipes or two or more pairs of pipes in the heat exchanger, for. B. transverse to the circulating air flow direction, are arranged side by side and these pipe pairs as described above ben heated, the sum of the temperature values, which are on a straight line transverse to the direction of air circulation and to the flame tubes measured on the pipe parts hit by the line, within each, Cross section of the heat exchanger duct (section perpendicular to the direction of the circulating air flow) equal.

In general, the flame and the arrangement and design according to the invention pipes first a temperature compensation within the heat exchanger channel be enough. To achieve one on the entire cross section (across the stream direction) of the circulating air flow in the circulating air volume everywhere the same temperature ture is the sum of the temperature values, which are on a straight line in Um Air flow direction measured on the flame tube parts hit by the line everywhere, in the cross-section of the heat exchanger channel (seen across the um air flow direction) - especially at the heat exchanger duct outlet - same be made. This goal is achieved by the aforementioned solution.

Using the schematic representation of an embodiment, individual units of the invention explained.

In the accompanying drawing, a total of 20 designated heat exchanger shear channel, which is to be flowed through by circulating air 21 in the direction of the arrow shown. The channel 20 has an entrance 22 and an exit 23 and, inter alia, opposing longitudinal walls 24 and 25 . In the drawn heat exchanger channel 20 there are two (= a pair) schematically illustrated flame tube meanders 26 and 27 (27 = dashed), which extend side by side in the circulating air flow direction from the inlet 22 to the outlet 23 . The flame tube meanders 26 and 27 have inlets 28 and 29 at the inlet 22 and outlets 30 and 31 at the outlet 23 . Each meander consists of straight tube parts 32 and deflections 33 . The straight tube parts 32 extend essentially from one longitudinal wall 24 to the other longitudinal wall 25 , the deflections 33 are adjacent to the longitudinal walls 24 and 25 . The long straight tube parts 32 make the heat exchanger shown approximately a cross-flow type device.

In the heat exchanger duct 20 , the meanders 26 and 27 are arranged in the illustrated embodiment such that the straight pipe parts 32 (and the deflections 33 ) lie in pairs next to one another, so that the circulating air 21 to be heated can just flow through between two such pipes. In fact, there are significantly more than two pairs of flame tubes in a heat exchanger. In general, the entire volume of the heat exchanger channel is filled so tightly by flame tubes that the circulating air 21 can flow through the air resistance between the tubes with optimal heat transfer and without disturbing, that is, excessively stressing the fan.

If, for example, the heating gas flowing in at the inlet 28 of the flame tube meander 26 has a temperature value of 10 and it is assumed that the temperature value at each deflection 33 decreases by one unit, the temperature value of the flame tube meander 26 at the first deflection 9 is a second deflection 8 , a third deflection 7, etc .; ie gas leaves (with this linear cooling) the meander 26 at its outlet 30 according to the drawing with the temperature value 4 . The same applies to the flame tube meander 27 , if this occurs at the inlet 29 with the temperature value 10 , the heating gas leaves the meander 26 at the outlet 31 with the temperature value 4 . If you add the temperature values in each plane perpendicular to the direction of flow 34 of the circulating air 21 , the same sum can be seen everywhere in each of these planes, the sum 19 in the top level of the drawing, the sum 15 in the next level of the drawing, etc. Added If the temperature values which follow one another on lines parallel to the direction of flow 34 from the channel or tube level to the tube level (of the straight tube parts 32 ), the same sum results on all these lines, namely the sum 19 + 15 + 11 + in the exemplary embodiment shown 4 = 45. This means that each air flow line element, that is, each "air streak" in the flow direction 34 , leaves through the heat exchanger duct 20 at the same temperature, irrespective of the position of the duct cross section (measured perpendicular to the flow direction 34 ) of the duct located.

LIST OF REFERENCE NUMBERS

1-19

Temperature values and their sums

20

heat exchanger duct

21

circulating air

22

entrance

23

output

24

.

25

longitudinal wall

26

.

27

Flame tube meander

28

.

29

Inlet

30

.

31

outlet

32

straight pipe part

33

redirection

34

flow direction

Claims (8)

1. Textile machine with circulating air heating with the help of at least one heat exchanger, which serves to pass the circulating air ( 21 ) heat exchanger channel ( 20 ) with channel inlet and outlet ( 22 , 23 ) and from the entrance to the outlet extending channel walls ( 24 , 25 ), characterized in that a gas-heated heat exchanger with at least two spatially parallel side by side within the heat exchanger channel ( 20 ) extending flame tubes, which can be flowed through by the heating gas, is provided and that adjacent flame tube parts ( 26 , 27 ) antiparal lel, so in the heating gas flows through in opposite directions. 2. Textile machine according to claim 1, characterized in that the flame tubes within the heat exchanger channel ( 20 ) in the form of tube grinding ( 26 , 27 ), in particular as a meandering grinding, are arranged. 3. Textile machine according to claim 2, characterized in that when formed according to the cross-flow type, the length of the duct wall ( 24 ) to duct wall ( 25 ), that is to say transversely to the circulating air flow direction ( 34 ), the tube loop parts ( 32 ) extend large against the length of the opposite duct walls ( 24 , 25 ) adjacent pipe deflections ( 33 ). 4. Textile machine according to claim 3, characterized in that the longer, transverse to the air flow direction ( 34 ) extending Rohrtei le ( 32 ) are substantially straight. 5. Textile machine according to at least one of claims 1 to 4, characterized in that an even number of flame tube loops ( 26 , 27 ) is provided. 6. Textile machine according to claim 5, characterized in that a pair of flame tube loops ( 26 , 27 ) through which the heating medium can flow antiparallel are provided. 7. Textile machine according to at least one of claims 1 to 6, characterized in that the sum of the temperature values ( 1 to 10 ), which are measured on a straight line in the circulating air flow direction ( 34 ) on the pipe parts ( 32 ) hit by the line, everywhere in the cross section of the heat exchanger channel ( 20 ) is the same. 8. Textile machine according to at least one of claims 1 to 7, characterized in that the sum of the temperature values ( 1 to 10 ), which are on a straight line transverse to the direction of air flow ( 34 ), in particular also transverse to the longer pipe parts ( 32 ) the pipe sections hit by the line are measured, is the same everywhere in the longitudinal section of the heat exchanger.