JPS63198228A - Manufacture of circular fluorescent lamp - Google Patents

Abstract

PURPOSE:To obtain a uniform tube diameter by winding a heated glass tube and almost simultaneously injecting the inert gas in multiple stages with the pressure increased in sequence. CONSTITUTION:The inert gas such as nitrogen fed from a gas bottle is set to respective pressures of the first-third stages by a regulator valve 1. According to the experiment, 0.2-0.4kg/cm<2> is preferable for the set pressure of the first stage, 0.5-1kg/cm<2> for the second stage, and 1-2kg/cm<2> for the third stage. Solenoid valves 2 are operated upon receiving signals from a timing controller or the like, the valve 2 of the first stage is opened almost concurrently with the winding, the valve 2 of the second stage is opened about 0.5-0.7sec after the start of the winding, and the valve 2 of the third stage is opened 0.7-1.0sec after the start of the winding to inject the inert gas. After all valves 2 are closed and the winding is completed, a solenoid valve 3 is opened, and the pressure in an injection circuit is reduced to the pressure near the atmospheric pressure. Accordingly, a nearly uniform tube diameter can be obtained at portions where the winding is started and completed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing an fC monkey-shaped fluorescent lamp in which a desired shape is obtained during the bending process of the ring-shaped fluorescent lamp.

[Conventional technology]

In conventional devices and bending methods, a heated glass tube is wound and at the same time inert gas is injected at a pressure slightly higher than atmospheric pressure using a solenoid valve or the like so that the cross section becomes approximately circular.

Incidentally, related techniques of this type include, for example, Japanese Patent Publication Nos. 45-11232 and 52-118865.

Examples include No. 57-180848 and No. 58-12237.

[Problem that the invention seeks to solve]

In the prior art described above, the glass tube is heated to a temperature necessary for bending, but at the end of winding, the glass tube is cooled down, so that the diameter of the glass tube becomes smaller than the diameter at the beginning of the second winding.

An object of the present invention is to inject the inert gas to be injected at the time of winding in multiple stages to make the above-mentioned glass tube diameter or shape into a desired shape.

[Means for solving problems]

To solve the above problem, the inert gas in the first stage is injected at almost the same time as the heated glass tube is wound up, and the pressure in the second stage is further increased. By injecting the third stage inert gas, it is possible to obtain a substantially uniform tube diameter around the entire circumference of the monkey-shaped fluorescent lamp. In addition, when the inert gas injection circuit prevents deformation (sag) after winding by cooling air after one winding is completed, almost at the same time, that is, immediately before the head moves, the inert gas injection circuit was opened to the atmosphere, and the pressure was set close to atmospheric pressure so that when the head moved, the residual pressure in the injection circuit would not affect the shape of the lamp that was bent next.

[Effect]

The temperature of the glass tube immediately before winding has an almost uniform temperature distribution that is higher than the softening temperature of the glass tube as a whole. To prevent cracks in the upper neck section at the end of winding.

During heating, the lower and upper neck parts are heated several tens of degrees higher than other parts.

When winding such a glass tube, the temperature of the glass tube is cooled at the end of the winding, so injecting inert gas only in the first stage does not make the glass tube narrow and the desired tube diameter cannot be obtained. Then, in the middle of winding, the second stage.

By injecting the inert gas in the third stage at a higher pressure than in the first stage, cooling of the glass tube can be covered and a desired tube diameter can be obtained.

Also, when the primary head moves to the winding position by opening the injection circuit to the atmosphere after winding.

It is possible to prevent the glass tube from becoming thicker due to residual pressure in the circuit.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a diagram showing the piping system for the bending process of an annular fluorescent lamp, and shows the injection route of the inert gas to be injected. In the figure, 1 is an inert gas pressure reducing valve.

2 is a solenoid valve that opens at an appropriate timing to inject cine active gas, 3 is a solenoid valve that releases residual pressure in the circuit after winding is completed, 4 is the center pulp fixed side, 5 is the rotating center pulp, 6 The head is equipped with the function of holding the annular fluorescent lamp 7 and creating a vacuum inside.

An inert gas such as nitrogen, which is supplied from a gas cylinder or the like at several kilograms/cm2, is set to the respective pressures from the first stage to the third stage by a pressure reducing valve (equipped with a pressure gauge) 1.

According to experiments, the set pressure of the first stage is 0.2 to 0.4 hours/c.
The pressure in the second stage of rn2 is preferably 0.5 to I Kg/cm, and the pressure in the third stage is preferably 1 to 2 Kg/cm.

The solenoid valve 2 for injecting the inert gas is activated by receiving multiple signals from a timing controller or the like, and the first stage opens at almost the same timing as the winding. The second stage solenoid valve is activated approximately 0.5 to 0.7 seconds after the start of winding.

The third stage solenoid valve opens after a further delay of 0.7 to 1.0 seconds and injects the cine active gas.

The solenoid valve 3 is a solenoid valve for reducing the pressure in the injection circuit to near atmospheric pressure after all the injection solenoid valves are closed.

〔Effect of the invention〕

According to the present invention, it is possible to adjust the injection timing or injection pressure of the inert gas according to the glass tube temperature or cooling condition during winding of the glass tube, and a desired lamp shape can be easily obtained. The shape of the annular fluorescent lamp thus obtained has a substantially uniform tube diameter at either the beginning or end of the winding.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a piping system during the bending process of an annular fluorescent lamp. 1... Pressure reducing valve, 2... Solenoid valve for injecting inert gas, 3... Solenoid valve for releasing residual pressure, 4... Center pulp fixed side, 5... Rotating center pulp ,6
...Holding head of annular fluorescent lamp, 7...Lamp.

Claims (1)

[Claims] 1. In an annular fluorescent lamp bending device equipped with a drum for heating and winding the glass tube, the inert gas injected during winding is injected in multiple stages with a phase shift, and A method for manufacturing an annular fluorescent lamp, characterized in that gas pressure is injected at a pressure higher than the injection pressure in the first stage, and the pressure is reduced to near atmospheric pressure after winding is completed and before the head moves.