JPH0329886B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an apparatus for producing flame-resistant yarn.

[Prior Art] Today, carbon fibers are attracting attention as a base material for forming composite materials by integrating them with matrices made of resins, metals, etc., and it can be said that such composite materials have reached the stage of practical use. Today, most carbon fibers are made using acrylonitrile fibers or what is commonly called pitch fibers as their raw materials. It is usually treated through a process of oxidizing the raw material fibers, which is called flameproofing treatment or oxidation treatment.

Now, this flame-retardant treatment or oxidation treatment (hereinafter simply referred to as flame-retardant treatment) is an oxidation reaction and is known to be accompanied by heat generation. It is known that the reaction causes an abnormal heat accumulation phenomenon, causing the reaction to run out of control. Therefore, how to set process conditions to prevent this runaway reaction from occurring is considered an important technical issue in the production of flame-resistant yarn, and various process conditions for this have been proposed in many literatures. .

[Problems to be Solved by the Invention] In the production of such flame-resistant yarns, unexpected changes in process conditions, unexpected abnormalities in the running of the fibers passing through the heat treatment chamber for flame resistance, for example, The thread wrapping around the guide rolls causes a runaway reaction, forcing production to be suspended until the reaction subsides.In some cases, this may lead to pollution problems due to a rapid increase in the concentration of exhaust gas from the heat treatment chamber. , abnormal situations may occur with the danger of explosion due to the sudden rise in temperature and pressure in the heat treatment chamber, creating a large management burden on the manufacturing site.

An object of the present invention is to reduce the management burden at the operational site in the production of such flame-resistant yarn.

[Means for Solving the Problems] The above object of the present invention is to continuously run fibers through a heated oxidizing atmosphere, during which time,
The apparatus for producing flame-resistant yarn that oxidizes the fibers includes a circulation duct for supplying and discharging heated air to a heat treatment chamber of the apparatus, a heating means for heating the air interposed in the circulation duct, and a heating means for heating the air. An air supply means for supplying air, an outside air introduction passage engaged with a circulation duct upstream of the air supply means via an outside air introduction valve, and a circulation duct upstream of the engagement position of the outside air introduction passage. a heated gas outlet path engaged via a heated gas outlet valve; and a cutoff valve that substantially blocks communication between the circulation duct between the outside air introduction valve and the heated gas outlet valve when the outside air introduction valve and the heated gas outlet valve are opened. , abnormal temperature detection means for detecting that the atmospheric temperature in the heat treatment chamber has risen above a predetermined temperature, abnormal decomposition gas concentration detection means for detecting that the decomposition gas concentration has risen above a predetermined concentration, and The introduction valve and the outlet valve are opened based on at least one kind of abnormality detection means among yarn running abnormality detection means for sensing a running abnormality and an abnormality signal obtained by the abnormality detection means, and the above-mentioned shutoff valve is opened. This can be achieved by a flame-resistant yarn manufacturing apparatus equipped with a valve opening/closing means that keeps the valve in a closed state.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The flame-retardant yarn manufacturing apparatus of the present invention (hereinafter referred to as the apparatus of the present invention) will be specifically described below with reference to the drawings.

That is, FIG. 1 is a schematic cross-sectional view of one embodiment of the device of the present invention. Heat treatment chamber 1 for flame-retardant treatment of raw material yarn (not shown) that continuously runs through
(The structure of such a flame-retardant heat treatment chamber is described in many literatures and is well known, so detailed illustrations are omitted). Circulation ducts 2 and 3 (2 indicates the air supply side and 3 indicates the exhaust side) are provided to circulate the air). A heating means 7 for heating the air to a certain temperature and an air supply means (usually a fan) 8 for supplying the air are interposed. On the other hand, in the heat treatment chamber 1, an outside air introduction path 4 is engaged with one end, a heated gas outlet path 5 is engaged with the other end, and an air supply means (not shown) is connected to the outside air introduction path 4.
In addition, the heated gas outlet path 5 includes an exhaust means (not shown).
is interposed. Further, the outside air introduction path 4 is provided with an outside air introduction valve 4', the heated gas outlet path 5 is provided with a heated gas outlet valve 5', and the circulation ducts 2 and 3 are provided with an outside air introduction valve 4', and a heated gas outlet valve 5' is provided in the circulation ducts 2 and 3. A shutoff valve 6 is provided to shut off. Furthermore, an abnormality detection means 9 is provided in the heat treatment chamber 1 for detecting an abnormality in the heat treatment chamber 1 and sending out a signal.

The abnormality detection means 9 includes abnormal temperature detection means for detecting that the temperature within the heat treatment chamber 1 has risen above a predetermined temperature, and abnormal temperature detection means for detecting that the concentration of gas within the heat treatment chamber 1 has risen above a predetermined concentration. Abnormal concentration detection means and, for example, photoelectric abnormality detection means that detect abnormalities in yarn running in the heat treatment chamber 1 (for example, yarn wrapping around rollers, yarn breakage, or occurrence of fuzz). Alternatively, a combination of these methods may be used.

Next, the operation and function of the above-mentioned implementation device will be explained. If, for example, the yarn breakage detection means 9 detects a yarn breakage during flameproofing treatment, an abnormal signal is output, and based on this signal, the outside air intake in the closed state is automatically or manually activated. The valve 4' as well as the heated gas outlet valve 5' are opened, and unheated outside air (usually room temperature air outside the heat treatment chamber 1, if necessary air kept at a particularly low temperature or other gas) is introduced all at once from the outside air introduction path 4, heated air in the heat treatment chamber 1 is led out all at once from the heated gas outlet path 5, and the temperature inside the heat treatment chamber 1 rapidly decreases, resulting in yarn breakage. Runaway reactions that are likely to be triggered are prevented.

At this time, the heating means 7 in the circulation ducts 2 and 3,
It is preferable that the air supply means 8 be temporarily suspended until recovery from the abnormal situation is completed, and if necessary, the shutoff valve 6 be closed. Although not mentioned above, the supply of new air and the partial discharge of gas in the heat treatment chamber in the steady state are carried out in the conventional manner.

Next, an example of the use of the device of the present invention will be described with reference to FIG. 2, which shows a schematic cross-sectional view of another example of the device.

In the apparatus example of the present invention shown in FIG. 2, in the apparatus shown in FIG. It is structurally different from the device shown in FIG. 1 in that the air supply means 8 for circulation interposed between the circulation ducts 2 and 3 is also used as a means for supplying and exhausting air in the event of an abnormality. It is something that A switching valve 4' is provided at a portion where the outside air introduction path 4 meets the circulation duct 3, and this switching valve 4' has a structure that can also be used to close the circulation duct. Further, a switching valve 5' is provided at a portion where the heated gas outlet path 5 meets the circulation duct 3, and this switching valve 5' has a structure that can also be used to close the circulation duct. It is preferable that the outside air introduction path 4 is connected to the circulation duct 3 at a position between the heating means 7 and the air supply means 8 so that the outside air introduced in the event of an abnormality does not pass through the heating means 7. An engagement may also be provided between the channel 5 and the heating means 7. In this case, the switching valves 4' and 5' provided in the outside air introduction path 4 and the heated gas outlet path 5 are activated, and the heating of the heating means 7 is stopped (if the heating means is an electric heater, the power is turned off). ), it is possible to considerably prevent the heat generated by the heating means from being transferred to the heat treatment chamber 1. Further, the switching valves 4' and 5' are automatically operated based on a signal issued by the abnormality detection means 9 in the heat treatment chamber 1,
An operating circuit (not shown) that introduces outside air into the heat treatment chamber 1 and discharges heated air in the heat treatment chamber 1 to the outside.
It is preferable to achieve complete automation by incorporating . Furthermore, the capacity of the air supply means 8 may be increased when an abnormality occurs. The operation of this embodiment can be understood in accordance with the embodiment shown in FIG. 1, so the details will be omitted.

[Effects of the Invention] The device of the present invention can detect abnormalities in the heat treatment chamber and oxidizing atmosphere, such as an abnormal shift of the atmospheric temperature control to a high temperature side that tends to cause a runaway reaction, thread breakage, and thread wrapping around the roller. Based on this detection signal, the structure is such that unheated outside air is introduced into the heat treatment chamber and heated air inside the heat treatment chamber is discharged, which prevents runaway phenomena from occurring. It also reduces the burden of process control for the process, and also prevents or quickly quells the problems that conventionally were difficult to quell in a short time once a runaway reaction started. This has the remarkable effect of solving the conventional problems peculiar to the flame-retardant process.

[Brief explanation of the drawing]

1 and 2 are schematic cross-sectional views of an embodiment of the device according to the invention. Explanation of symbols: 1; heat treatment chamber; 2, 3; circulation duct; 4; outside air introduction path; 5; heated gas outlet path;
4': Outside air introduction valve, switching valve, 5': Heated gas outlet valve, switching valve, 6: Shutoff valve, 7: Heating means, 8: Air supply means, 9: Abnormality detection means.

Claims (1)

[Claims] 1. In an apparatus for producing flame-resistant yarn in which fibers are continuously passed through a heated oxidizing atmosphere, during which the fibers are oxidized, heated air is supplied to and discharged from a heat treatment chamber of the apparatus. A circulation duct, a heating means for heating air and an air supply means for supplying air, which are interposed in the circulation duct and are engaged with the circulation duct upstream of the air supply means via an outside air introduction valve. a heated gas outlet passage that is engaged with a circulation duct upstream of an engagement position of the outside air introduction passage via a heated gas outlet valve, and the outside air introduction valve and the heated gas outlet valve are opened. a cutoff valve that substantially blocks communication of the circulation duct between the two valves when the heat treatment chamber is in the heat treatment chamber;
Abnormal temperature detection means for detecting that the ambient temperature has risen above a predetermined temperature, abnormal decomposition gas concentration detection means for detecting that the decomposed gas concentration has risen above a predetermined concentration, and a yarn for detecting abnormal running of the yarn. a state in which the inlet valve and the outlet valve are opened and the cutoff valve is closed based on at least one kind of abnormality detection means among the traveling abnormality detection means and an abnormality signal obtained by the abnormality detection means; A flame-resistant yarn manufacturing device equipped with a valve opening/closing means.