WO2004097316A1

WO2004097316A1 - Method for regulating a recirculating air machine

Info

Publication number: WO2004097316A1
Application number: PCT/DE2004/000805
Authority: WO
Inventors: Hans-Peter Prinzen
Original assignee: A. Monforts Textilmaschinen Gmbh & Co. Kg
Priority date: 2003-04-25
Filing date: 2004-04-17
Publication date: 2004-11-11
Also published as: DE10318761A1; TW200500584A

Abstract

The invention relates to a method for regulating a recirculating air drying/fixation machine. In the machine, the circulating air is accelerated using a circulation fan (8) depending on the speed or a reducing damper position thereof and is blown onto a textile web (1). In order to constantly regulate the pressure with which the circulating air (7, 14, 15) is incident on the textile web (1), the actual pressure is measured and is used to regulate the speed of the circulation fan (8) or the reducing damper position.

Description

"Method for controlling a machine operated with circulating air"

Description:

The invention relates to a method for controlling a drying and / or fixing machine operated with circulating air, in particular a textile machine, such as a tenter frame or hotflue, in which the circulating air is accelerated in at least one circuit and blown onto an object to be treated, in particular a textile web. The invention further relates to an apparatus for performing the method.

In the context of the invention, the air in the textile machines should preferably be blown from both sides at the same time, in particular by means of blow-out nozzles, onto the textile fabric web which has been transported in a spread manner. Although the invention was preferably designed for use in textile machines, in particular textile finishing machines operated with circulating air, such as stenter frames or hot flues, it is also advantageously used in other machines in which, similar to the textile machines, the pressure of the circulating air, with which this hits the respective object, is to be kept in a predetermined pressure range. “Recirculated air” is understood not only to mean air in the narrower sense but also any other treatment gas.

A textile machine, namely a stenter, in which the aforementioned method can be used, is described in EP 04 71 162 B1. Another textile machine, namely a hot flue, in which the method can be used advantageously, is described in DE 33 36 328 C2. In these machines, the circulating air is preferably at a pressure which is approximately the same in terms of space and time blown, textile fabric blown, for example to dry and / or fix it. In general, the circulating air pressure is specified by specifying the speed of circulation fans (fans) - speed control - which keep the circulating air in the circuit. Alternatively, for example, if the speed of the fan cannot be changed continuously or analogously, the air pressure is specified by adjusting (at least) one throttle valve - throttle valve control.

On the way inside the respective machine, the circulating air accelerated by the circulating fan hits the object to be treated (in particular the fabric) and arrives from there, e.g. after reflection on the object, through a flow filter and a heating register back to the fan. The blow-out means directed at the object (the fabric web) after the fan can be connected to bypass channels (so-called bypass) into which the heated circulating air is diverted with the help of a switching linkage, for example if there is otherwise a risk of the object (the Fabric).

Fluff filters are specified in the aforementioned European patent EP 0471 162 B1, a filter cleaning device is described in DE 33 36 333 C2. A bypass system with a switchable deflection channel for the circulating air is disclosed in DE 36 27 904 C2. Means for carrying out the task described above are therefore known per se. A problem in practice, however, is to recognize in good time or at all whether one or the other function is disturbed, in particular whether and when a lint filter has to be cleaned.

In conventional systems in which a circulating air circuit is maintained in accordance with the method mentioned at the beginning, the circulating air pressure is checked by specifying the fan speed (speed of the circulating fan) or by setting a throttle valve. This type of control has proven itself in practice. At least for the textile machine types described, it is standard equipment. With regular inspection of the fluff filters, the moving parts within the channels and other sources of interference, the proper functioning of the systems in question can be guaranteed. The regular inspections are complex. The invention has for its object to improve the above-mentioned method so that it detects the specified disturbance variables, and - if possible - even compensates. The regular inspection - generally with the machine stopped - should therefore be saved. Rather, it should only be checked if there is reasonable suspicion or cause to do so. The task is also to detect this suspicion or cause. For example, the aim is to identify soiled screens and preferably also to compensate for their degree of soiling to a certain extent and to detect machine defects, for example broken bypass flap linkages on deflection channels.

For the method mentioned at the outset, a first alternative of the solution according to the invention is that - in a machine with acceleration of the circulating air in the circuit with the aid of at least one controlled circulating fan depending on its speed, that is to say in speed control - the actual value of the pressure of the Circulating air is measured and that the pressure measurements obtained in this way are used to regulate the speed of the circulating fan for the purpose of setting a predetermined target value of the circulating air pressure. In a second alternative, the solution according to the invention is that in a machine with regulation of the acceleration of the circulating air in the circuit with the help of at least one adjustable throttle valve depending on its valve position, i.e. in the case of the rotary valve regulation, the actual value of the pressure of the circulating air is measured and that the pressure measurements obtained in this way are used to adjust the throttle valve for the purpose of setting a predetermined target value of the circulating air pressure. Some improvements and further refinements of the invention are specified in the subclaims.

For a textile finishing machine, e.g. for a stenter frame or a hotflue, the core of the invention is to measure the ambient air pressure directed at the respective textile fabric web, in particular the blow-out pressure of the nozzles directed towards the fabric web, and to regulate it to a constant pressure value. There- is achieved, for example, that the nozzle pressure does not drop even with gradually soiled lint filters. If any of the aforementioned disturbance variables occur, the speed (at least) of a recirculation fan is automatically changed or a throttle valve is adjusted by the respective control according to the invention.

According to the first alternative of the invention, the fan speed is no longer kept (approximately) constant but is regulated depending on the pressure present. The actual value of the circulating air pressure is measured and set to a target value by regulating the speed of the circulating fan, depending on the measured circulating air pressure. According to the second alternative of the invention, the throttle valve, which is located in a structurally advantageous position of the recirculating air circuit, no longer remains fixed in a specific flap position, but the flap position is adjusted depending on the recirculating air pressure. The actual value of the recirculating air pressure is measured and set to a target value by changing the flap position of the throttle valve (s) - depending on the measured recirculating air pressure.

The teaching according to the invention has thus opened up fundamentally new and significant ways of solving a task known per se. There is also an unexpected effect: the fan speed or throttle valve position influenced by the pressure control according to the invention provides the machine operator with information about faults in the circulating air circuit. According to a further invention, the speed of the recirculation fan should therefore be measured or the throttle valve position determined and used or calibrated to display (or report) faults or errors in the recirculation circuit or duct. The same applies to the second alternative, from which the damper position of the throttle valve is used to draw conclusions about the degree of contamination of the cleaning screen.

Based on the schematic representation of an embodiment, details of the invention for both of the aforementioned alternatives in a stenter are explained. Show it Flg. 1 a stenter with speed control; and Fig. 2 shows a tenter with throttle valve control.

The accompanying drawing shows in Fig. 1 and 2 a vertical section perpendicular to the longitudinal direction of a tenter. When this machine is operating, a fabric web 1 to be treated is held in chains 2 and 3 at its longitudinal edges in the transport direction of the web, that is to say in the direction perpendicular to the plane of the drawing, between two nozzle boxes, namely an upper nozzle box 4 and a lower nozzle box 5. The upper nozzle box 4 is located above the fabric web 1, the lower nozzle box 5 is located below the fabric web 1. The nozzle boxes 4 and 5 have (not shown) perforated or slot nozzles for blowing out treatment gas in the direction of arrow 6 from above and from below Fabric 1.

The treatment gas 7 is accelerated towards the nozzle boxes 4 and 5 in the direction of the arrow with the aid of at least one circulating fan 8. The circulating fan 8 has a controllable motor 9. In the exemplary embodiment, a bypass flap 10 and 11 is connected upstream of each nozzle box 4 and 5, which enables the flow of the treatment gas 7 either in the nozzle box 4 or 5 or past it in a bypass channel 12 or 13 to lead. The treatment gas flows from the nozzle boxes 4 and 5 in the direction of the arrow 6 drawn against the fabric web 1 and is reflected from there as return air 14 or 15. If the nozzle boxes 4 and 5, as usual and assumed in the drawing, consist of individual nozzle fingers extending from left to right in the drawing plane, the return air 14, 15 can flow up and down between the nozzle fingers approximately perpendicular to the fabric web 1. In this way, it arrives in a return flow chamber 16 and from there through a fluff filter 17 and - if necessary - a heating register 18 along the flow lines 19 back to the circulating fan 8.

According to the invention, in the exemplary embodiment, inside the nozzle boxes 4 and 5, preferably close to their outflow nozzles, air pressure measuring devices (pressure transmitter) 20 and 21 for the upper and lower air - that is, the air blown from above and below onto the fabric 1 - arranged. The pressure measuring devices 20 and 21 are coupled wirelessly or via lines 22, 23 to a control device 24.

In the first alternative, according to FIG. 1, a control device 24 is switched wirelessly or via lines 25 to the drive control of the circulating fan 8 or motor 9. In the second alternative, the control device according to FIG. 2 - similarly wireless or via lines 25 - is switched to a servomotor 30, preferably with a mechanically coupled absolute rotary encoder 31. The servomotor 30 adjusts the flap 33 of the throttle valve 34 via a linkage 32.

In this way it can be achieved that the nozzle pressure of the nozzle boxes 4 and 5 is to be recorded permanently and to be kept at a desired value via the control. In order to avoid unnecessary switching or control impulses, it may be advisable to use the actual values determined with devices 20 and 21, e.g. to dampen electrically or pneumatically. A pressure value (in percent of the maximum value or mbar) is thus set up in the system designed according to the invention.

A speed indicator 26 can be assigned to the circulation fan 8 or motor 9 in the context of the invention in speed control. In the throttle valve control, the valve position indicator 26 takes the place of the speed indicator 26. In the exemplary embodiment, the respective device 26 (FIGS. 1 and 2) has a scale 27 with a central region 28 (so-called “green” region) within which a pointer 29 is to move. When the pointer 29 emerges from the central region 28, If the machine operator has reasonable grounds for suspicion or reason to look for the possible disturbance variable, a regular inspection of the system parts in question, that is, a check without any special reason, can be omitted.

LIST OF REFERENCE NUMBERS

1 = fabric 2, 3 = chain 5 = nozzle box

arrow

gas treatment

Fan (fan)

Motor, 11 = bypass flap, 13 = bypass duct, 15 = return air

return flow

lint

heater

Flow lines, 21 = pressure gauge, 23 = line

Control device = line

display

scale

the central region

pointer

servomotor

Rotary encoder

linkage

flap

throttle

Claims

claims:

1. A method for controlling a drying and / or fixing machine operated with circulating air, in particular a textile machine, such as a tenter frame or hot flue, in which the circulating air accelerates in at least one circuit and is blown onto an object to be treated, in particular a textile fabric (1) , characterized in that - in a machine with acceleration of the circulating air in a circuit with the aid of at least one controlled circulating fan (8) depending on its speed - the actual value of the pressure of the circulating air (7; 14, 15) is measured and that the pressure measurements obtained in this way are used to regulate the speed of the fan (8) for the purpose of setting a predetermined target value of the air pressure.

2. A method for controlling a drying and / or fixing machine operated with circulating air, in particular a textile machine, such as a tenter frame or hot flue, in which the circulating air accelerates in at least one circuit and is blown onto an object to be treated, in particular a textile fabric (1) , characterized in that - in a machine with regulation of the acceleration of the circulating air in the circuit with the aid of at least one adjustable throttle valve depending on its valve position - the actual value of the pressure of the circulating air (7; 14, 15) is measured and that the so pressure measurements obtained to adjust the throttle valve (34) for the purpose of setting a predetermined target value of the circulating air pressure.

3. The method according to claim 1, characterized in that the speed of the circulating fan (8) is measured and used to display the disturbances relating to the circulating air circuit and is calibrated.

4. The method according to claim 1 with lint filter (17) inserted in the circulating air circuit, characterized in that the speed of the circulating fan (8) is used to indicate contamination of the lint filter (17) and is calibrated.

5.Device, in particular a tenter frame or hot flue, with nozzle boxes (4, 5) provided on both sides of a textile fabric (1) which is transported and from which treatment air (7) can be blown onto the fabric (1) with the aid of blow-out nozzles, for carrying out the Method according to one of claims 2 to 4, characterized in that at least one pressure measuring device (20, 21) is provided within at least one of the nozzle boxes (4, 5) and that the pressure measuring device (20, 21) via a controller (24) with the Speed control of a recirculation fan (8) for setting a predetermined target value pressure is formed in the nozzle box (4, 5).

6. The device according to claim 5, characterized in that the fan (8) is associated with a speed measuring device (26) which indicates whether the speed of the fan (8) is in the permissible range or not.

7. The method according to claim 2, characterized in that the position of the flap (33) of the throttle valve (34) is determined and used to display the disturbances relating to the circulating air circuit and is calibrated.

8. The method according to claim 2 with lint filter (17) inserted into the circulating air circuit, characterized in that the position of the flap (33) of the throttle valve (34) is used to indicate contamination of the lint filter (17) and is calibrated.

9. A device, in particular a tenter frame or hot flue, with nozzle boxes (4, 5) provided on both sides of a textile fabric (1) which is transported and from which treatment air (7) can be blown onto the fabric (1) with the aid of blow-out nozzles, for carrying out the Method according to one of claims 2 and 7 to 9, characterized in that at least one pressure measuring device (20, 21) is provided within at least one of the nozzle boxes (4, 5) and that the pressure measuring device (20, 21) via a controller (24) with an actuator (30) and an absolute rotary encoder (31) for adjusting the Flap (33) of the double flap (34) for setting a predetermined setpoint pressure in the nozzle box (4, 5) is formed.

10.The device according to claim 9, characterized in that the double flap (34) is assigned to the flap position-related display device (26) which indicates whether the speed of the fan (8) is within the permissible range or not.