JPS62197427A - Apparatus for ultraviolet curing - Google Patents

Abstract

PURPOSE:To continuously and satisfactorily cure an UV-curable coating material applied to the surface of a fine wire-like object, by converging ultraviolet rays on the wire-like object through a hollow tube by means of a reflecting mirror, feeding cooling air to the inside of the reflecting mirror and feeding another gas to the inside of the hollow tube. CONSTITUTION:Cooling air is fed to the inside of a box 1 in order to cool an ultraviolet lamp 4 and a hollow tube 25 and exhausted from an exhaustion duct 8 to the outside through a path as shown by the arrows. An inert gas (e.g., nitrogen gas) is fed to the inside of the hollow tube 27 from one of its ends for the purpose of removing oxygen or the like purpose and passed through the tube. In an early stage of drawing optical fibers or during inspection, the hollow tube 25 can be separated into two semicircular sections 25 A and 25 B by separating box members 1 A and 1 B from each other by operating a plunger 28. In this way, a distance equal to an opening stroke 25 can be kept between the sections 25 A and 25 B.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultraviolet curing device, and particularly to a curing device that continuously cures an ultraviolet curable coating material applied to the surface of a thin wire-shaped object by irradiating it with ultraviolet rays. Regarding equipment.

[Prior Art] In recent years, with the development of optical fiber technology, equipment for fiber coating has been developed.
Those featuring electrodeless lamps using magnetrons sold by Systems Corporation,
It is possible to use the one disclosed in Japanese Unexamined Patent Publication No. 55-152567, or the one shown in FIG. 9 proposed by the present applicant in Japanese Patent Application No. 59-43185.

In FIG. 9, 1 is a housing, and inside the housing 1, elliptical cylindrical reflecting mirrors 2^ and 2B each having a shape of an ellipse divided into two parts along its short axis are disposed facing each other. Narrow gaps 3^ and 3B for cooling are installed in parts of both reflecting mirrors 2^ and 2B. 4 is an ultraviolet lamp for an ultraviolet light source, such as a high-pressure mercury lamp, which is arranged with its center line aligned with the first focal axis of the ellipse, and 5 is an ultraviolet lamp arranged with its center line aligned with the second focal axis of the ellipse, and which is For example, it is an ultraviolet-transmissive hollow tube through which an optical fiber 6 as a linear object passes.

In this example, in order to cool the ultraviolet lamp 4 and the hollow tube 5 from the surroundings, cooling air is introduced into the housing 1 from the air filter 7, and is then discharged from the exhaust duct 8 to the outside via the path shown by the arrow. The hollow tube 5
An inert gas, such as nitrogen gas, is introduced into the hollow tube 5 from one end thereof for the purpose of removing oxygen and is allowed to flow therethrough.

In the ultraviolet curing device configured as described above, while an object to be irradiated with ultraviolet light, for example, an optical fiber 6, is moved at high speed within the hollow tube 5 along its center line,
The ultraviolet rays from the ultraviolet lamp 4 installed at the first focal axis are focused along the center line of the hollow tube 5, which is the second focal axis, effectively forming an ultraviolet curable coating around the optical fiber 6. Materials can be hardened.

Therefore, such hollow tubes 5, including this example, have generally been adopted as integral round-shaped vibes or square-shaped pipes.

Generally, when drawing an optical fiber, the tip of the base material is restrained while the other end is heated and melted, and the optical fiber is passed through an ultraviolet curing coating device while being drawn. However, it has been considered difficult to guide the material into the integrated hollow tube 5 shown in FIG. 9 in terms of workability. In particular, if the optical fiber is first guided to the winding drum, it is extremely inconvenient when inspecting the equipment during the work. I would like to configure the curing device to be set to working condition.

Therefore, from the viewpoint of workability as mentioned above, a split type hollow tube is desired, and as mentioned above, the coating equipment already has a split type structure so as not to hinder the work. This is the current situation.

In the first place, the purpose of providing this hollow tube 5 is to block the outside air since there is a risk that lateral wobbling will occur if the drawn thin optical fiber 6 comes into direct contact with cooling air.
In addition, in order to cool the optical fiber without causing lateral wobbling, and to block oxygen that has the effect of inhibiting the curing of the ultraviolet curable coating material, an inert gas is flowed along the hollow tube 5, etc. Therefore, if the hollow tube 5 is an integrated type, there is no problem in this respect, but if it is a split type, its sealing performance becomes a problem.

The conventional split-type hollow tube was constructed as follows. That is, as shown in FIG. 10A, the hollow tube 15 is configured with two equally divided members 15A and 15B, or as shown in FIG. 10B, the hollow tube 15 is configured with a flange portion 1δ. Split members 15C and 15 having
However, in the case of the hollow tube 15 shown in FIG. 10Δ, the sealing performance is poor as described above. In other words, in order to improve the sealing performance, the surfaces of the mating parts are polished with sufficient precision after cutting, but even so, when installed in the device, the combined state does not provide good sealing performance. Not maintained.

That is, since cooling air is supplied to the ultraviolet curing device as in the example shown in FIG. 9, air flows into the hollow tube 15 when the air pressure is positive, and when the air pressure is negative, the dividing member 15
^ and 15B'' will sag outwards in its center, compromising the sealing performance in any case.

In addition, in the case of the split type shown in FIG. 10B, the sealing performance is better due to the contact surface between the flange parts 16, but on the other hand, the flange parts 16
The mating part becomes an obstacle, and light from the direction of the mating surface (in the direction indicated by the arrow) is absorbed by the mating part, or the central axis of the hollow tube 15 is exposed to light from the surroundings due to light shielding by the flange, etc. Not only will the light not be evenly focused, but the manufacturing cost will be high.

Therefore, it is conceivable to form the hollow tube 15 by combining two divided members 15E and 15F having two arcuate cross-sectional shapes, as shown in FIG. 10c. That is, by adopting such a configuration, it is possible to suppress deflection even if the air pressure outside the hollow tube 15 becomes negative pressure, but on the other hand, the joint portion is still not completely sealed. When nitrogen gas was supplied on a trial basis, the oxygen concentration inside the hollow tube did not fall below 1%.

[Problems to be Solved by the Invention] The purpose of the present invention is to focus on the various problems mentioned above, to solve them, to provide a simple structure, to obtain uniform light condensation,
Particularly, the object of the present invention is to provide an ultraviolet curing device that can maintain good sealing properties and achieve cost-effective curing for split-type hollow tubes.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes an ultraviolet light generation source having a linear light source, and two halves arranged so as to be divisible in a direction parallel to the linear light source. It consists of a hollow tube that accommodates a linear object so that it can move in parallel directions when two half-cylinders are joined at their opposing joint surfaces, and a hollow tube that accommodates the linear object so that it can move in parallel directions. A reflector that focuses light through a hollow tube, a means for supplying cooling air into the reflector, a means for supplying other gas into the hollow tube, and a means for keeping the pressure difference between the inside and outside of the hollow tube within a predetermined pressure range. The present invention provides an ultraviolet curing device characterized in that it is equipped with means for controlling.

[Examples] Examples of the present invention will be described below in detail and specifically based on the drawings.

1 and 2 show an embodiment of the present invention, where 25 is a hollow tube such as a quartz tube, and in this example, the housing 1 is used as a reflecting mirror as shown in FIG. It is composed of two housing members 1^ and IB that can be separated in the direction of the long axis of the two ellipses. When these housing members 1^ and IB are separated, the reflector 2 is also disassembled into the reflectors 2^ and 2B shown in FIG. 9, and the hollow tube 25 is also disassembled as shown in FIG. The housing member IA is separated into two divided members 25A and 25B.
and moved together with the IB.

This is a guide member that can freely slide along the 6th position of the 1st position R11L + fist + 'Ip 97th position.

Reference numeral 28 denotes a plunger that is driven to separate or join the above-mentioned housing member 1^ and IB, and this plunger 28 can be operated via a driving means (not shown). 29 is a board for mounting this device, 30 is a board for mounting two hollow tube dividing members 25A and 25B to the housing parts l^ and IB.
These are holding members fixed to the upper surface of each.

In the ultraviolet curing device configured in this manner, the state shown in FIGS. 1 and 2 is maintained during use, but the plunger 28 is operated at the initial stage of drawing the optical fiber or during inspection. By separating and moving the housing member 1^ and IB, the hollow tube 25 can be separated into two semicircular divided members 25^ and 25B as shown in FIG. , an interval corresponding to the opening/closing stroke 2S shown in FIG. 1 can be maintained between the divided members 25^ and 25B.

Therefore, in this example, the above-mentioned dividing members 25^ and 25B are formed by cutting a cylindrical quartz tube in half, but after cutting the cylindrical quartz tube vertically in half, the joining surface 25C is maintained at a good flatness. In order to improve the sealing performance when joined, it is preferable to further frost both polished surfaces, or to frost one surface and leave the other polished. do.

In addition, regarding the wall thickness t of members 2SA and 25B, the wall thickness t should be thinner than 1.2 mm (thus, the sealing performance tends to decrease, and if the wall thickness t is thicker than 10 mm, the transmittance of ultraviolet rays will decrease and the coating Because the hardenability of the material is impaired,
It is necessary to keep the wall thickness within 1.2mm≦t≦10mm.
It is preferably kept within the range of 1.5@- or more and 51 or less.

Furthermore, under the conditions described above, members 25A and 25
When the outer diameter 0-D of B is made smaller than 511 m, member 25
When A and 258 are joined to form the hollow tube 25, even if you try to maintain this form due to the difference in internal and external pressure of the hollow tube 25, it becomes difficult to maintain the balance mechanically. , the sealing performance is likely to be impaired. Also, members 258 and 2
When the inner diameter I-D of 5B is larger than 50+ss, if the internal pressure is even slightly higher than the external pressure when the hollow tube is used as described above, the pressure difference will cause a force in the direction that separates the members 25A and 25B. This also impairs the sealing performance.

Next, when the dividing members 25A, 25B, the reflecting mirror 2, and the housing 1 are kept in the joined state as shown in FIG.
I will now discuss the differential pressure between the inside and outside that should be maintained.

The length of such a hollow tube 25 is set to 15 to 25 cm, and now, between the pressure PIN supplied into the hollow tube 25 and the pressure Pout of the cooling air guided around the hollow tube 25. If the pressure difference is ΔP1, that is, ΔP−Pout−P+s, ΔP is preferably −5 mmH2O to 7 mmN2O.

When the pressure difference ΔP is higher than 7 mm of water column H2O, such a pressure difference is applied from the outside of the dividing members 258 and 25B, so that the joint state of the hollow tubes 25 is maintained, but the slight gap between the joints Air flows into the tube, and the oxygen concentration increases rapidly, as shown in the experimental results described below.

In addition, if the pressure difference ΔP is lower than water column -5 + am I (20), the internal pressure becomes too strong due to the external pressure and acts to separate the members 25A and 25B, causing the joint surfaces to separate. Sealing performance is impaired.

Therefore, in the present invention, such a difference between the internal and external pressures in the hollow tube 25 is maintained, but this pressure difference can be maintained, for example, by controlling the blower and the exhaust fan and using an elliptical reflector. This can be achieved by adjusting the pressure of the cooling air supplied around the hollow tube 25 in the ultraviolet lamp 2. In this case, it is necessary to cool the tube wall of the ultraviolet lamp 4, so the exhaust air volume is 1 m' /l1lin~10 m3/win.

FIG. 4 shows an example of a control circuit that controls the blower and exhaust fan so that the pressure difference as described above is maintained. 41 and 42 are pressure sensors that detect the internal pressure and external pressure of the hollow tube 25, respectively, and serve as conduits for extracting the internal pressure of the hollow tube 25, as shown in FIG.

Thus, the internal pressure sensor 41 and the external pressure sensor 4
After amplifying the detected pressure signal from 2 with amplifiers 43 and 44, a comparator 45 compares the pressure signal again, and further supplies this comparator output signal to a first phase shift circuit 46 to generate a control operation signal, This control operation signal controls the triac 47 to control the rotational speed of the blower FAN1.

Furthermore, the output from the comparator 45 is superimposed on the differential pressure setting signal taken out from the sliding resistor 48B based on the voltage from the reference voltage source 48^ in the differential pressure setting unit 48 to form a differential pressure signal. Furthermore, the air volume adjustment signal from the air volume regulator 49 and the above-mentioned differential pressure signal are supplied to the comparator 50. This comparator output signal is supplied to the second phase shift circuit 51, and the triac 52 is controlled by the control operation signal from the circuit 51 to control the rotation speed of the exhaust fan FAN 2. The inventors of the present invention, who vary the air volume while keeping it constant, investigated the relationship between the pressure difference between the inside and outside of the hollow tube as described above and the oxygen concentration mixed into the hollow tube through experiments, and obtained the data shown in Figure 6. At the same time, we were able to confirm the preferred range proposed by the present invention.

In the above experiment, the outer diameter was 24 mm and the inner diameter was 19 mm.

Therefore, half-split quartz tubes with a wall thickness of 2.5 mm were used, and after finishing the joint surfaces to be flat as described above, they were kept in a joined state. In order to maintain the joined state, both ends of one of the above-mentioned divided members are fixed, and springs are provided at corresponding positions on both ends of the other divided member, and this spring causes this divided member to be pulled to one side. It was made to be biased toward the dividing member of , so that it was supported at both ends.

Then, 517IIlin and 10fL/
It was confirmed that the oxygen concentration inside the hollow tube was maintained at 1% or less in the inside and outside of the hollow tube by purging with nitrogen gas at a flow rate of 100.

Furthermore, under conditions such as differential pressure within the regulated range, a drawn optical fiber coated with an ultraviolet curable coating material of approximately 50 to 150 microns was guided into the hollow tube, and a 3.5 k
As a result of ultraviolet curing using one VI metal halide lamp, it was possible to cure the film to a sufficiently satisfactory state at a linear feed rate of 3.5 m/sec.

FIG. 7 shows another embodiment of the invention. In this example, automatic pressure regulating valves 10 and 11 are provided at the intake section of the intake duct 9 and the outlet section of the exhaust duct 8, respectively.
0, the pressure inside the reflector 2 is reduced, and when the pressure falls below a certain first set pressure, the valve is automatically opened due to the difference between the air pressure outside the reflector 2 and the air pressure outside the reflector 2. Further, the regulating valve 11 automatically opens in the same way when the pressure inside the reflecting mirror 2 is increased and becomes equal to or higher than the second set ξ certain pressure.
By mechanically controlling the pressure inside the reflecting mirror 2 within a predetermined range in this manner, it is also possible to keep the pressure difference between the inside and outside of the hollow tube 25 within a predetermined range.

Furthermore, FIG. 8 shows a regulating valve 10 as described above.

10B, IIA, and IIB are provided around the inlet and outlet sides of the reflector 2, respectively, so that both the amount of air flowing in and the amount of air flowing out can be adjusted, thereby controlling the inside of the reflector 2. The air pressure can be controlled within a predetermined range.

[Effects of the Invention] As explained above, according to the present invention, it is possible to join two members in which a hollow tube movably housing a linear object coated with an ultraviolet curable coating material is divided into equal parts. In an ultraviolet curing device that is maintained by maintaining the condition, the air pressure supplied around the hollow tube is controlled within a predetermined pressure range. It is possible to prevent air from leaking inside and increase the amount of oxygen and hinder curing, and also to control the pressure difference between the gas inside and outside the hollow tube to within a predetermined pressure difference. It was possible to further enhance the leakage prevention effect as described above.

Furthermore, by frosting at least one of the joint surfaces of the split hollow tube described above, it is possible to contribute to further enhancing the leakage prevention effect.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the overall configuration of the ultraviolet curing device of the present invention, FIG. 2 is a schematic cross-sectional view thereof, FIG. 3 is a cross-sectional view for explaining the dimensions of the hollow tube according to the present invention, and FIG. Fig. 5 is a configuration diagram showing an example of a control device for controlling the cooling air pressure of the ultraviolet curing apparatus of the present invention, Fig. 5 is a schematic diagram showing the arrangement of the pressure sensor, and Fig. 6 is a schematic diagram showing the arrangement of the pressure sensor.
Figures 7 and 8 are characteristic curve diagrams showing the relationship between the pressure difference inside and outside the hollow tube and the oxygen concentration inside the hollow tube obtained from the Hayabusa ATh% experiment. A schematic diagram showing the configuration of the pressure control device, Figure 9 is a schematic diagram showing the outline of the configuration of a conventional ultraviolet curing device, and Figure 10^, Figure 108, and Figure 10C are the conventional diagrams divided into two parts. It is a perspective view which shows the example of the hollow tube which made it possible. l... Housing, 2... Reflector, 4... Ultraviolet lamp, 5.15.25... Hollow tube, 6... Optical fiber, 7... Air filter 8... Exhaust duct, 9... Air supply duct, 10, IOA, 10B, 11.11^, IIB... Regulating valve, 15^, 15B, 15c, 15D, 15E, 15F,
25^, 25B...Hollow tube dividing member, 25G...Joint surface, 41.42...Pressure sensor, 43.44...Amplifier, 45.50...Comparator, 46.51...・Phase circuit, 48...Differential pressure setting device, 49...Air volume regulator, 47.52...Triac, FAN 1, FAN 2...Fan. Patent applicant: Japan Synthetic Rubber Co., Ltd. Oak Seisakusho Co., Ltd.

Claims (1)

[Scope of Claims] 1) Consists of an ultraviolet ray generation source having a linear light source and two semi-cylinders disposed so as to be divisible in a direction parallel to the linear light source, with the two semi-cylinders facing each other. a hollow tube that accommodates a linear object so as to be movable in the parallel direction when joined at a bonding surface; and a hollow tube that focuses ultraviolet light from the ultraviolet source on the linear object through the hollow tube. A reflecting mirror, means for supplying cooling air into the reflecting mirror, means for supplying another gas into the hollow tube, and means for controlling the pressure difference between the inside and outside of the hollow tube within a predetermined pressure range. An ultraviolet curing device characterized by comprising: 2) The ultraviolet curing apparatus according to claim 1, wherein the means for controlling the pressure difference between the inside and outside of the hollow tube within a predetermined pressure range includes a blower and an exhaust fan. Curing equipment. 3) In the ultraviolet curing device according to claim 1 or 2, the predetermined pressure range is −5 mmH_
An ultraviolet curing device characterized in that the temperature is from 2O or more to +7mmH_2O or less. 4) The ultraviolet curing device according to claim 1, 2, or 3, wherein at least one of the joint surfaces of the hollow tube is frosted. Curing equipment.