JPH0443530A - Washing method of funnel neck tube for cathode-ray tube - Google Patents

Abstract

PURPOSE:To wash a funnel neck tube in a short time and safely without generating erosion blotches on the surface of the neck of the tube by sealing the opening at the neck side of the tube, pouring a glass erosive solution in the tube, and then soaking the tube in an ultrasonic washing tub to wash the tube. CONSTITUTION:As a glass erosive solution, a mixture acid selected from fluoric- sulfric acid, fluoric-hydrochloric acid, and fluoric-nitric acid which does not generate silicate type scales or a fluoride sediment is suitable, because those scales and sediment are generated when the acid erodes the surface of the neck, attached to the inner surface, and disturb an even erosion. And the density of each acid is favorably 3 to 10 %. The funnel neck tube 10 the glass erosive solution is poured therein is soaked in an ultrasonic washing tub 22, and by giving supersonic oscillations to ghe glass erosive solution at 20 KHz to 1 MHz for 0.5 to 1 minute, only the inner surface is eroded 1 to 10 mum. And as the washing solution filled in the washing tub, a pure water and the like which does not erode the outer surface of the neck may be used.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for cleaning funnel neck tubes for cathode ray tubes, and more specifically to a method for cleaning the inner surface of the neck portion of funnel neck tubes for color cathode ray tubes. be.

[Prior Art] The neck portion of a cathode ray tube is required to have high withstand voltage characteristics because an electron gun is loaded therein and electron beams are emitted from the neck portion.

Generally, the inner surface of the neck glass tube used for the neck part contains reaction products between the refractory and glass during the tube manufacturing process.
Foam lines from foaming of the refractory, pieces of the refractory, and metal pieces from the low-pressure blower during tube forming are often present.

In addition, prior to manufacturing a cathode ray tube, a funnel neck tube is manufactured by welding a neck glass tube and a funnel. At this time, volatile substances of the glass component are generated due to the heating of the burner, and this is caused by the welding on the inner surface of the neck. Attach nearby.

When a cathode ray tube is manufactured using a funnel neck tube that has these reaction products, bubble streaks, or attached foreign matter,
These become serious defects that cause dielectric breakdown when high voltage is applied. That is, the inner surface of a cathode ray tube bulb is coated with internal graphite called dag, but since the inside of the bulb is evacuated, when a high voltage is applied, the electric field tends to concentrate at the end of the dag. In the vicinity, dielectric breakdown is very likely to occur. Therefore, if reaction products, bubble streaks, or attached foreign matter are present on the inner surface of the neck, especially near the edge of the doug, the electric field will concentrate there, causing dielectric breakdown that penetrates the neck glass.

From the above, it is necessary to obtain a funnel neck tube having a neck portion with extremely high internal surface cleanliness, and for this purpose it is effective to clean the neck portion with a glass corrosive solution.

However, fine scratches such as roller scratches and cutting chute scratches are generally formed on the outer surface of neck glass tubes during the tube manufacturing process, and the neck of funnel neck tubes with such scratches can be removed using a glass-erosive solution. If you clean it with water, the scratches will expand and foreign matter from the outside will easily adhere to them.
Further, there arises a problem of deterioration of withstand voltage characteristics.

As a solution to these problems, the Special Public Interest Publication Act of 1977-1984
No. 438 discloses a method of cleaning the inner surface of a funnel neck tube by having a pair of nozzles facing each other from above and below in the tube axis direction, and causing cleaning liquid sprayed from the nozzles to collide within the tube to create turbulent flow. In Japanese Utility Model Application Publication No. 54-48581 devised by the present applicant, a funnel neck tube is held with the wide opening of the funnel facing down, the tip of the neck tube is closed with a spherical stopper, and the funnel is closed. An apparatus is disclosed for cleaning internal surfaces by jetting a dilute acid solution from a nozzle located below.

[Problems to be Solved by the Invention] However, in the case of Japanese Patent Publication No. 47-40436, the cleaning liquid tends to scatter around, which is particularly dangerous for workers if an acid solution is used as the cleaning liquid. Also, Utsukai Showa 54-48
When the device No. 5 [i1 is used, there are problems in that it takes a long time to clean and the texture is uneven due to dripping.

An object of the present invention is to provide a method for cleaning the inner surface of the neck of a funnel neck tube for a cathode ray tube in a short time and safely without causing unevenness to the touch.

[Means for solving the problems] The method for cleaning funnel neck tubes for cathode ray tubes of the present invention includes the following steps:
The neck side opening of the funnel neck tube is sealed, and after injecting a glass corrosive solution into the funnel neck tube, the tube is immersed in an ultrasonic cleaning tank for cleaning, thereby touching only the inner surface of the funnel neck tube. shall be.

In the present invention, it is preferable to use a cap that improves acid resistance to seal the neck side opening, and a mixed acid selected from fluorosulfuric acid, fluorohydrochloric acid, and fluoronitric acid is suitable as the glass corrosive solution.

[Operation] In order to clean the inner surface of the neck portion of the funnel neck tube in the method of the present invention, the opening on the neck side is first sealed;
From the viewpoint of workability, it is preferable to seal this with an acid-resistant cap, and Teflon or vinyl chloride is suitable as the material for the cap.

Next, a glass corrosive solution is injected into the funnel tube whose neck opening is sealed as described above. The glass corrosive solution to be injected does not need to fill the inside of the funnel neck tube, but it is sufficient to fill the inside of the neck where reaction products, bubble streaks, or attached foreign matter are present. The glass corrosive solution to be used is fluorinated sulfuric acid and fluoride, which do not generate silicic acid scale or fluoride precipitates that are generated when touching the inner surface of the neck and stick to the inner surface and interfere with homogeneous tactile action. A mixed acid selected from hydrochloric acid and fluoronitric acid is suitable.

The concentrations of hydrofluoric acid, sulfuric acid, hydrochloric acid, and nitric acid used in the mixed acid are preferably 3 to 10%.

The funnel neck tube, into which the glass corrosive solution was injected in this way, was immersed in an ultrasonic cleaning tank and heated at 20 KHz.
- By applying ultrasonic vibrations to the glass-invasive solution for 0.5-1 min at IMHz, only its inner surface is exposed to I~l
011m is eroded. The appropriate cleaning liquid to be filled in the tactile cleaning tank is pure water, which does not corrode the outer surface of the neck, and the funnel neck pipe may be immersed up to the funnel in the ultrasonic cleaning tank. , if the ultrasonic vibration is transmitted to the glass corrosive solution, there is no problem even if it is only a part of the neck part.

[Example code] The present invention will be explained below based on examples.

FIG. 1 is a sectional view of a funnel neck tube in which a cap is attached to the neck side opening and a mixed acid is injected into the inside thereof. In the figure, 1O is a funnel neck tube made by welding a neck glass tube and a funnel with a gas burner, 11 is a neck part, 12 is a neck side opening, 13
14 indicates a funnel-side opening, 14 indicates a funnel neck weld, and 21 indicates a Teflon cap.

When the inner surface of the neck part 11 of this funnel neck pipe 1O was observed using an electron microscope, reaction products with the refractory, microbubble streaks caused by the refractory, and metallic foreign substances thought to be contaminants from the blow air were found. In addition, volatile substances of glass components generated during welding the neck glass tube and the funnel were observed especially near the funnel neck welding part 14.

Next, the neck side opening 12 of this funnel neck pipe lO
After sealing with a cap 21 made of Teflon, a mixed acid of 5% hydrofluoric acid and 7% nitric acid was injected from the funnel side opening 13 to fill the inside of the neck portion 11.

Thereafter, as shown in FIG. 2, the funnel neck tube 10 is immersed in an ultrasonic cleaning tank 22 filled with pure water, held using a fixing fitting 23, and then the ultrasonic frequency is increased to 30K.
The cleaning was performed at Hz for 30 seconds, and the inner surface of the neck portion 11 was eroded to a thickness of 2 μm. Next, the funnel neck tube 10 was pulled up from the ultrasonic cleaning tank 22, the cap 2N was removed, and the funnel neck tube 10 was washed with pure water and further dried with hot air.

When the inner surface of the neck portion 11 of the funnel neck tube IO was observed using an electron microscope, reaction products, microbubble streaks, and attached foreign matter were removed, and no uneven erosion was observed.

[Effects] As explained above, according to the method for cleaning funnel neck tubes for cathode ray tubes of the present invention, only the inner surface of the neck can be cleaned in a short time without causing uneven erosion, resulting in excellent cleanliness of the inner surface of the neck. A funnel neck tube can be efficiently obtained.

Furthermore, since there is no risk of the glass corrosive solution scattering around, cleaning work can be carried out safely.

[Brief explanation of the drawings] Figure 1 is a cross-sectional view of a funnel neck tube with a cap attached to the neck opening and mixed acid injected into it, and Figure 2 is a cross-sectional view of the funnel neck tube shown in Figure 1 after cleaning. FIG. IO...Funnel neck tube 11...Neck part 12
... Neck side opening 21 ... Cap 2
2... Ultrasonic cleaning tank patent applicant Nippon Electric Glass Co., Ltd. Representative Representative Kishi 1) Saku Kiyoshi

Claims (3)

[Claims] (1) Seal the neck side opening of the funnel neck tube, inject a glass corrosive solution into the funnel neck tube, and then immerse the tube in an ultrasonic cleaning tank for cleaning, thereby corroding only the inner surface of the funnel neck tube. A method for cleaning funnel neck tubes for cathode ray tubes. (2) A method for cleaning a funnel neck tube for a cathode ray tube according to claim 1, characterized in that the neck side opening is sealed with an acid-resistant cap. (3) The method for cleaning funnel neck tubes for cathode ray tubes according to claim 1, characterized in that a mixed acid selected from fluorosulfuric acid, fluorohydrochloric acid, and fluoronitric acid is used as the glass corrosive solution.