JP3856479B2 - Fabric heat treatment method and apparatus - Google Patents

Abstract

Textiles, e.g. cops of spun cotton yarn, are heat treated in steamer 6 by:- evacuating the steamer using pump 2; admitting liquid, e.g. water, into steamer bath 8 from tank 19; heating the bath to form steam for a preselected time; and pumping the liquid back into tank 19 for reuse. The treatment may be repeated with liquid from chemical tank 20, and then with liquid wax from tank 21. The steamer is then evacuated, and the textile cooled and dried. The first vacuum is at least 1000 mbar absolute. The process reduces recondensation and energy losses.

Description

The present invention relates to a method for heat treating a fabric, in particular a span cup or bobbin, in a heated steamer connected via a valve to a water and / or chemical supply and a vacuum pump, and for carrying out this method Relates to the device.
By “woven fabric” is meant any structure made from the raw materials of the fabric and includes both fibrous and sheet-like materials.
It is known that heat treatment has a positive effect on the yarn and the like for subsequent processing.
The fabric can also be adjusted or finished by adding chemicals, if necessary, and treating in the vapor phase.
Suitable steamers have been known for many years and substantially include a cylindrical boiler that can be closed with a rotatable cover. There is a water bath inside the steamer, steam is generated by a heating device, and appropriate heat treatment of the introduced material is performed. A vacuum is applied before the water bath heating device is switched on so that the steam can better penetrate the interior of the fabric.
These known steamers have the disadvantage that a large amount of energy is required to maintain it in a vacuum and the vapor must be removed again with a vacuum pump and condensed again. As a result, little vapor penetrates the material to be processed and / or processing time is increased.
One object of the present invention is to provide a method and apparatus that uses less energy, provides better penetration into the material to be processed, and further reduces cycle time and overall heat treatment.
The present invention provides a method of heat treating a fabric in a heated steamer connected to a water and / or chemical supply and a vacuum pump via a valve, which is treated in the first stage of the method. The material to be charged is charged into the steamer,
In the second stage, the vacuum pump is then switched on (activated or activated) to a vacuum of at least 100 mbar in the steamer,
In the third stage, the supply valve of the water and / or chemical supply section is opened and a predetermined amount of liquid is placed in the steamer to form a liquid bath,
In the fourth stage, the liquid bath and the vapor phase to be formed are heated to a predetermined temperature,
After holding the material to be treated in the saturated vapor phase for a preselected time, the liquid is pumped from the steamer into the container,
In the fifth stage, the vacuum pump is turned on again,
In the sixth stage, after a pre-selected evacuation, cooling and drying time, the vacuum pump is switched off and the ambient air is put into the steamer,
At the final stage, the material is removed from the steamer.
In the second stage, a vacuum of at least 50 mbar is preferred.
In the case of a liquid bath with a volume of 300 liters, the method according to the invention saves energy on the order of 12 kWh per cycle or on the order of 35-40 kWh per treatment. Furthermore, it is not necessary to recondense the water vapor discharged by the pump during evacuation. The volume saved without recondensing is about 20 liters per processing cycle.
This provides the further advantage that the recirculation of liquid according to the present invention also significantly reduces the amount of new water required.
Yet another advantage resides in a simple and economical supply of chemicals and / or finishing additives that place little or no load on the vacuum pump.
The heat treatment or the results obtained thereby can be improved in a simple way by repeating the second to sixth stages at least once.
The heat treatment can be optimized by continuously increasing the temperature of the vapor phase from the first heat treatment to at least one subsequent heat treatment.
During the heat treatment, it is preferred that a temperature of the vapor phase of at least 350 ° K is established in the first cycle and a temperature of at least 380 ° K is established in yet another cycle.
By extending the holding time at a constant temperature during the next heat treatment, the result can be improved without increasing energy consumption.
Aeration can save further energy, which further reduces the overall processing time. That is, at an intermediate stage before the end of the first heat treatment, the vacuum is interrupted and then re-evacuated.
Water and / or chemicals are preferably supplied from a container that is sized according to the volume of the liquid bath in the steamer, which is the liquid that was lost, i.e. the vaporized material and in the evacuation. A closed system is formed with the steamer in which only liquid due to residual moisture is sent back from the outside. This allows for recirculation of liquids and / or chemicals and is therefore particularly economical and environmentally friendly.
The present invention further provides an apparatus for performing the above-described method. The apparatus includes a heating steamer connected via a valve to a water and / or chemical supply and a vacuum pump, the liquid and / or chemical supply comprising at least one container, a pump, and at least two valves. These valves control the flow of liquid into and out of the steamer.
It is preferable to provide an electric heating device at least in the space of the liquid bath in the steamer. Such an electric heating device is particularly advantageous since it can be controlled very flexibly and thereby has a positive effect. Other heating systems, such as steam heating systems, can also be used economically depending on the available energy.
The vacuum pump is preferably a water ring pump or a rotary blade pump. Water ring pumps are very cost effective and are suitable for vacuums up to 30 mbar. For vacuums up to 5 mbar, a rotary vane pump is required.
An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings.
FIG. 1 is a simplified schematic diagram of a steam apparatus for processing cups according to the present invention.
FIG. 2 is a temperature characteristic graph for the vapor phase in the steamer of the installation according to FIG.
FIG. 3 is a pressure graph for the ambient atmosphere associated with FIG.
According to FIG. 1, the exhaust line is indicated by reference numeral 1. A vacuum pump 2 having an electric motor M is connected to the exhaust line 1. The vacuum (suction) line 3 is connected to the input (inlet) side of the vacuum pump 2 (rotary blade pump), and communicates with the interior of the steamer 6 via the valve V1 and the suction line 4.
A further valve V2 is also arranged in the suction line 4 and connects to the air line 5.
A liquid bath 8, an aqueous liquid 9 reaching level N1 and an electric heating device 10 are arranged inside a steamer 6 known per se.
One end of the steamer 6 is provided with a rotatable cover 7 having a vertical rotation shaft 7a. The cover 7 is opened and the material G to be treated is introduced into the steamer 6 where steam treatment is performed.
The feed line 11 leads from the electric heating device 10 to the control unit, and its adjustment function is represented by +/−.
The liquid line 12 is led from the steamer 6 and connected to the pump line 13 and the supply line 22.
The pump line 13 reaches the valves V7, V8 and V9 via the valve V3, the liquid pump 14 provided with the electric motor M, and the pressure line 15. One side of the valves V7 to V9 is connected to the lower part of the liquid containers 19 to 21 via the inlet / outlet lines 16 to 18. Each of these liquid containers (tanks) has aeration lines 19 ′ to 21 ′.
Valves V4 to V6 are also arranged in the inlet / outlet lines 16 to 18 and connected to the supply line 22.
The operation of the arrangement according to FIG. 1 is relatively simple and the inside of the steamer 6 is desired via the vacuum lines 3 and 1 by closing the valve V2 and opening the valve V1 and switching on the vacuum pump 2. Evacuate to low pressure. As a result, the material G to be processed is also substantially free of entrapped air or entrained air.
The valve V4 of the water tank 19 is then opened and the valve V9 is kept closed so that water is drawn into the steamer via the supply line 22 and the liquid line 12, and the liquid bath 8 is filled to level N1. The valve V4 is then closed, the main voltage is switched on and the electric heating device 10 is activated simultaneously, so that a vapor phase is formed inside the steamer 6 and penetrates the material G as saturated vapor.
After a predetermined holding time, the control unit switches off the heating device 10, opens the valves V3 and V9, keeps the valve V4 closed, switches on the liquid pump 14, pumps water back to the water tank 19, Return the level to about N2. The resulting moving air can escape via the aeration line 19 '.
Similarly, acid or base is supplied from the chemical tank 20 to the steamer 6 and then pumped back again.
Yet another advantage of this configuration is that it is connected to the liquid-wax tank 21 after the last steaming process in order to facilitate the processing of the material G, ie the spun yarn in the form of a cup. is there.
FIGS. 2 and 3 show the heat treatment characteristics of the actual cup, starting from an ambient pressure of 1000 mbar. For illustrative reasons, FIG. 3 shows the low pressure omitted.
As shown in FIG. 3, the steamer 6 is evacuated to a pressure of 5 mbar, then water from the water tank 19 is introduced and heated to produce a vapor phase having a temperature of about 350 ° K. Hold constant for 0 minutes (see Figure 2). During this process, the pressure in the steamer 6 rises to about 420 mbar.
Next, the vacuuming is interrupted, and the remaining amount of vapor is discharged into the air (aeration) through the suction line 4 and the valve V2 (see FIG. 1).
As shown in FIG. 3, a vacuum of 5 mbar (negative pressure) is again established and the second treatment cycle is started. In this case, the temperature of the vapor phase is increased to 380 ° K. and the pressure is increased to a positive pressure of 1300 mbar during heating of the liquid supplied from the chemical tank 20.
The same thing occurs in the third cycle, and the aqueous bath solution from the liquid-wax tank 21 is used to form the liquid bath 8.
It has been found that increasing the heating and holding times in subsequent cycles relative to the first cycle is very advantageous in terms of optimization of the heat treatment.
First cycle C is the first evacuation process. V begins and lasts for 3.0 minutes, 2nd and 3rd cycles C and 3. Each C lasts 4.0 minutes. The entire heat treatment is the fourth evacuation process 4. Finish after V, during which residual moisture is removed from the material. The material is spun cotton yarn, and the cup weighs 120 g untreated.
As can be seen in FIGS. 2 and 3, the complete heat treatment including the wax application to the yarn takes only a total of 18.5 minutes despite the very large cup.
Depending on the material to be processed and the processing required, it is advantageous for economic reasons to further connect a steam condenser (condenser) upstream of the vacuum pump 2.
This process can also be carried out under a vacuum with a pressure in excess of 50 mbar. However, especially when the material is heavy and / or compressed, the process time increases and the quality of the process decreases.

Claims (11)

It is connected to the water and / or chemical supply section (19 to 21) via a valve (V4 to V9) and a pump (14) equipped with a valve (V3) and vacuumed via valves (V1, V2). in the pump connected heated steamer (2) (6), as a first step, the steamer (6), was charged with material (G) to be processed, a plurality of consecutive stages performed thereafter the gas evacuated, process the fabric (G) in the vapor phase during the predetermined time, cooled, dried and evacuated, finally taking out fabrics (G) from the steamer (6), the fabric (G ) Is a heat treatment method,
In the second stage, the vacuum pump (2) is switched on until the inside of the steamer (6) reaches a vacuum with an absolute pressure of at least 100 mbar,
In the third stage, the supply valves (V7 to V9) of the water and / or chemical supply section (19 to 21) are opened, a predetermined amount of liquid is introduced into the steamer to form a liquid bath (9),
In the fourth stage, the liquid bath (9) and the vapor phase to be formed are heated to a predetermined temperature by means of an integrated heating device (10),
After holding the material (G) to be treated in the saturated vapor phase for a preselected time, the liquid is pumped from the steamer (6) into the containers (19-21),
In the fifth stage, the vacuum pump (2) is actuated again,
In the sixth stage, after a preselected evacuation, cooling and drying time, the vacuum pump (2) is switched off and ambient air is introduced into the steamer (6);
In the last step, the material (G) is removed from the steamer (6). 2. A method according to claim 1, wherein the vacuum obtained in the second stage is at least 50 mbar. The method according to claim 1 or 2, wherein the second to sixth steps are repeated at least once. 4. A method according to claim 2 or claim 3 wherein the vapor phase temperature is increased from the first heat treatment to at least one subsequent heat treatment. 5. The method of claim 4, wherein during the heat treatment, a vapor phase temperature of at least 350 ° K is established in the first cycle and a temperature of at least 380 ° K is established in another separate cycle. 6. A method according to claim 4 or claim 5, wherein the constant temperature period during the first heat treatment is shorter than that during the next heat treatment. 7. A method according to any one of claims 4 to 6, wherein the vacuum is interrupted and then re-evacuated at an intermediate stage before the end of the first heat treatment. Water and / or chemicals are supplied from a container sized according to the volume of the liquid bath in the steamer, and together with the steamer forms a closed system in which only the lost liquid is sent back from the outside. 8. A method according to any one of claims 1 to 7, wherein the liquid is due to vaporized material and residual moisture in the evacuation. 9. An apparatus for carrying out the method according to any one of claims 1 to 8, comprising a heating steamer connected via a valve to a water and / or chemical supply and a vacuum pump. An apparatus in which at least one container, a pump, and at least two valves are provided in the liquid and / or chemical supply, the valves controlling the flow of liquid into and out of the liquid steamer. The apparatus according to claim 9, wherein the electric heating device is provided in the space of the liquid bath at least inside the steamer. The apparatus according to claim 9 or 10, wherein the vacuum pump is a water ring pump or a rotary vane pump.

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