Heat treatment apparatus for synthetic yarn

Abstract

A heat exchange surface is formed at one side of an elongate closed vessel, an electric heater extends vertically in said vessel, said heater being surrounded by a heat resistant and liquid permeable layer of porous substance, the lower portion of which is submerged in a heat medium liquid which gets rise upward from its free surface by capillary action whereby the heat medium liquid permeating in said porous substance is vaporized by heating of said electric heater.

Description

This invention relates to an improvement of extender apparatus, false twisting apparatus and extender-false twisting apparatus for synthetic yarn. More particularly, the present invention is contemplated to furnish an improved heat treatment apparatus for synthetic yarn in which an evacuated elongate vessel is filled with a small amount of heat medium liquid in its bottom to be heated with a heater submerged therein and with saturated vapor thereby produced from the heat medium liquid, the heat exchange surface formed at one side of the closed vessel is heated to perform heat treatment of yarn passing in an elongate groove formed at the outside of said heat exchange surface.

Heretofore, known apparatus of this kind is such that an electric heater is submerged in a heat medium liquid filled in the bottom of an elongate exacuted closed vessel and low boiling point material vapor existing in the upper part of the heat medium vapor in said vessel is introduced to a header disposed at the outside of the upper portion of the vessel wherein the low boiling point material vapor and condensate of the heat medium vapor are to be separated.

However since such vessel is elongate shape, the free surface of the heat medium liquid or vaporing area and also the size of a heater submerged therein are so limited that it is difficult to enlarge a heat transfer area between the heat medium liquid and the electric heater. Further flowing of the low boiling point material gas existing in the upper portion of the vessel into the header is caused by the pressure drop in the header ducts its natural cooling. Therefore its flowing movement is very slow and the low boiling point material gas tends to stay in the upper portion of the vessel thus the temperation of this portion comes to be locally lower.

One of the object of this invention is to increase heat transfer area between the electric heater and heat medium liquid and also to increase the vaporing area of the heat medium liquid in the closed vessel.

Other object of this invention is to unify temperature distribution throughout the length of the elongate closed vessel.

The apparatus of the present invention is such that the outside of the heater is covered by porous fine metal wire netting, texture or bundle of heat resistant material and by submerging the lower portion of said porous material in a small amount of heat medium liquid, heat from the heater is transferred directly by conduction to the porous metal during the time which the heat medium liquid attaches to the porous metal by capillary action caused by its surface tension thus the heat medium liquid is heated through the porous metal into vapor. As a thin film layer of the heat medium liquid is formed on the outer circumferential surface of the fine metal wire, heat from the heater is well conducted to the liquid thus a large amount of vapor can be generated.

other objects and advantages of the present invention will become more apparent from the following description with reference to the accompanying drawings in which:

FIG. 1 is a longitudinal section view of an apparatus of the present invention.

FIG. 2 is a section view taken along the line II--II in FIG. 1.

FIG. 3 is a longitudinal section view of a heater.

FIG. 4 is a partial longitudinal section view of another embodiment.

FIG. 5 is a section view taken along the line V--V in FIG. 4.

FIG. 6 is a longitudinal section view of still another embodiment.

As shown in FIGS. 1 - 3, a closed vessel 2 is consisted of a yarn contacting plate 1, a back plate 3 and side plates 3', 3'. The plate 1 has a curved surface or groove. 7 is an electric heater which is closedly surrounded by heat resisting and liquid permeable porous substance 4 for ex. fine metallic wire net, or texture or bundle, the diameter of fine metallic wire being 0.05 - 1 mm.

After the closed vessel 2 is completely evacuated, a small amount of heat medium liquid 6 is filled in an amount that the lower portions of said metallic substance 4 and electric heater are submerged in the heat medium liquid 6 and the upper portions of them are supported by metal fitting 5 between the yarn contacting plate 1 and back plate 3.

One example of a temperature controller is consisted of a narrow tube 8 extending from the closed vessel, a bellows 9 subjected to vapor pressure and an electric converter 10 for turning on or off the electric source of said electric heater 7 with variation of vapor pressure in the closed vessel. 14 is a length of yarn to be treated. 15 is a free surface of the heat medium liquid 6. 16 is a heat medium vapor chamber.

From the upper portion of the closed vessel 2 is communicated to a header 11 through a pipe 12.

This pipe is partially formed a throttle 17 or an orifice is provided in the pipe. From the bottom of the header 11, a narrow tube 13 extends and opens into the heat medium liquid 6.

Now description is made to the operation of this apparatus.

Since the porous metallic substance 4 is formed of fine metallic wire, texture or bundle, the heat medium liquid permeates into the upper portion of the porous metallic substance 4 due to capillary attraction caused by surface tension.

Heat from the electric heater 7 is conducted directly to the metallic substance 4. Since the porous metallic substance 4 is made of a number of fine wires, its surface area is so wide that its heating area to the permeating heat medium liquid is also large. Thus with comparatively small amount of the heat medium liquid, comparatively large amount of heat is transferred thereby vapor generation is greatly increased. Further, since the heat medium vapor passes through the throttle 14 having small cross sectional area, the vapor passes this portion comes in faster speed. Accordingly, the heat medium vapor in the upper portion of the closed vessel 2 is absorbed in said fast blowing stream and introduced into the header thus it will not stay in the same spot. Accordingly the inert gas in the closed vessel will not separate from the heat medium vapor and flows in the header 11 and therein, separates from the heat medium vapor.

The heat medium vapor condensates with the heat of the header 11 and returns through the narrow pipe 13 to the lower portion of the closed vessel 2. If a large amount of the inert gas comes to accumulate, this will be discharged by appropriate method, for ex. by opening the purge pipe.

The apparatus of the present application is so constructed as above, an abundant volume of vapor is produced from the heat medium liquid whereby when the temperature of the heat contacting plate temporarily drops, the temperature of it is instantly restored to the normal temperature thus it maintains the uniform temperature. Therefore the yarn to be heat treated is given always uniform temperature thus its heat treatment efficiency is increased.

In FIG. 4 and 5, there is shown another embodiment in which a header 11 having rectangular cross section is disposed at the top portion of the vessel 2, an orifice 14 is formed as a throttle and a yarn passing groove 15 is formed on the surface of the yarn contacting plate 1. Other like reference numerals indicate like parts in FIGS. 1 - 3 and have the same functions respectively.

Still another embodiment is shown in FIG. 6 in which a header 11 has an upwardly projecting portion 16 from which a purge pipe 17 extends, the tip 18 of which is closed.

Other like reference numerals indicate like parts in FIGS. 4 and 5 and perform the same functions.

Having described the preferred embodiments of the invention, it should be understood other structural modifications may be resorted without departing from the spirit of the invention.

Claims

What is claimed is:

1. Heat treatment apparatus for synthetic yarn having an elongate closed evacuated vessel having a heat exchange surface at its outside face, said closed vessel being filled for a small portion of its height with heat medium liquid, and a heat medium vapor chamber formed on and above the free surface of the heat medium liquid, said apparatus comprising:

A. an elongate porous wire substance supported and extending in the elongate closed vessel, the major upper part of which is exposed to the vapor chamber above the free surface of the heat medium liquid, and the lower part of which is submerged in the heat medium liquid;

B. an elongate electric heater provided in and in contact with said porous substance in the elongate closed vessel, throughout substantially the full height of said porous substance;

C. a header upon the exterior of said vessel adjacent its upper portion and communicating therewith;

D. a conduit depending from said header and connected to said vessel below the level of said heat medium liquid;

E. there being a throttle in the connection between said vessel and header;

F. said vessel having a plain heat exchange surface.

2. In the heat treatment apparatus of claim 1, there being an elongate yarn-passing groove in said heat exchange surface.

3. In the heat treatment apparatus of claim 1, an upwardly projecting portion on the top of said header; and a purge pipe at one end connected to said upwardly projecting portion, its other end being closed.