US1875819A

US1875819A - Method of frosting the inner surface of alpha glass bulb

Info

Publication number: US1875819A
Application number: US480278A
Authority: US
Inventors: Naruse Tomisaburo
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-09-20
Filing date: 1930-09-06
Publication date: 1932-09-06
Anticipated expiration: 1949-09-06
Also published as: NL54255C; FR702317A; GB369887A; DE663883C

Description

T. NARUSE Sept. 6, 1932.

METHOD OF FROSTING THE INNER SURFACE OF A GLASS BULF Filed Sept. 6, 1950 INVENTOR. TING-ruse A TTORNEYS.

Patented Sept. 6, 1932 UNITED STATES PATENT OFFICE TOMISABURO NABUSE, OF UCEIYAMASHITA-GHO, KOJ'IMAGHI-KU, TOKYO, JAPAN METHOD OF FROSTING THE INNER SURFACE OF A GLASS BULB Application filed September 6, 1930, Serial No. 480,278, and in Japan September 20, 1929.

This invention relates to a method offrosting a portion of the inner surface of a glass bulb of an electric lamp; consisting in first injecting in the bulb a special etching liquid through a narrow tube and thereupon extracting said liquid therefrom; said liquid containing a powder selected from a group consisting of powdered starch and cornflour, which acts to give cohesiveness to the liquid, to stir the liquid when it is injected in the bulb, whereby a sharp, clear, dividing line, between the frosted and transparent parts of the bulb and the smooth even surface of the frosted part are obtained.

More particularly, the purpose of the invention is to obtain by the aid of a special etching, liquid and quickly the uniform edge or dividing line and the smooth even surface of the frosted part, whereby beautifullooking lamps can be made.

Now, if the method of frosting a glass bulb by pouring in and sucking out a corrosive liquid without a powder through a narrow tube be employed in frosting only a part, not the whole, of a glass bulb, inconveniences are chiefly caused by the excessive fluidity of the liquid.

Because of this fluidity, the liquid causes vortex motion while being pouredinto the bulb through a narrow tube and numerous wavelets are produced on the surface of the liquid, causing a zigzag edge of the frosted surface, or the liquid splashes and stains such part as is desired to be left transparent.

And now, if a glass bulb is frosted by pouring in and sucking out an etching liquid which contains liquid state mucilage or other viscous materials, say viscous starch, through a narrow tube; then above mentioned zigzag line will be more smooth, but

on-account of the stronger etching action in the 'lower part of the bulb than at the upper part of it, caused by the considerable time which is necessary in pouring and sucking out the liquid, that is to say, the bottom of the bulb keeps longer contact with the liquid than theupper part, consequently Vertical lines or horizontal circular lines are pro- 1 'duced on the frosted part. 5.0 This invention aims. at securing perfect finish of the frosted part of an electric bulb, by removing such defects as are experienced when a corrosive liquid without a powder is used, namely:

(1) first, decreasing the excessive fluidity of the liquid, to lessen the possibility of the wavelets being produced by the vortex motion of the liquid, and to prevent the liquid from splashing;

(2) secondly, accelerating the mixing proc- 6o xissugf the liquid when it is poured into the (3) thirdly, in order to lessen the strong corroding .or etching action at the lower part of the bulb where the liquid, after being poured in, remains longest in contact with the bulb; this method employs an etching liquid containing some powder (e. g. starch, corn flour), which affects the etching action of the liquid very slightly and the specific gravit of which is somewhat greater than that 0 any other elements contained therein.

In order that the invention may be more fully understood, a practical example is given below: 7

Parts Hydrogen fluoride 38 Ammonium fluoride 38 Sulphuric acid 5 Water 15 Now, the desired etching liquid can be ob tained first by mixing together the above mentioned elements and then by mixing into it American flour whose quantity is 20% of the mixture. It would be needless to say that the elements should vary according to the nature of the glass, and it has been found that 30 parts each of hydrogen fluoride and ammonium fluoride are eflective. And as to ,the relation between the specific gravity of the liquid and that of the powder it is enough if the powder be heavy enough to sink easily in the liquid.

Two examples of a suitable apparatus are shown in the accompanying drawing.

Fig. 1 shows in elevation an apparatus for this method, partly in section.

Fig. 2 shows other example for this method.

According to Figs. 1 and 2, above mentioned corrosive liquid is injected and sucked out of the bulb (1) by one or two narrow tubes (2). In the apparatus shown by Figure 1 the liquid (5) is saved in the tank (3) and to inject the liquidin the bulb push the'piston (4) downwards as the arrow (at) shows, and to suck the liquid out of the bulb pull the piston (4i) upwards as the arrow ((1') shows. In the apparatus shown by Fig. 2 the liquid (5) is saved in the tank (3) and when the tank is situated at the position that the liquid level is placed above the bulb (1) the cock (6) is opened, then the liquid in- 1' ected in the bulb, until the liquid level in the bulb reaches to the required height. After corrosion is finished, the tank is lowered until all the liquid in the bulb is sucked out.

As regards the advantages of the said invention, among others, is pointed out the possibility of obtaining a sharp, clear line between the transparent and the frosted part, in as much as the vortex motion of the liquid can be lessened to the limit even when 1t is poured into and sucked out of the glass bulb under quicker action than when the etching liquid without powder is used, to say nothing of the ease of obtaining the beautiful finish of the work, for the powder mixed in the liquid helps to stir up the liquid completely, because greater momentum is given to the powder while being poured into'the glass on account of its greater specific gravity than that of any other element contained therein, and at the same time the said powder sinks or settles easily and lessens the corroding action at the lower part of the bulb to some extent and thus saves the frosted surface from ugly wavelets. 7

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare what I claim is z- 1. A method of frosting a portion of the inner surface of a glass bulb of an electric lamp; consisting in first injecting in the bulb liquid to alter the etching action in the a special etching liquid through a narrow tube and thereupon extracting said liquid therefrom; said liquid containing a powdered material selected from a group consisting of starch and cornfiour, which acts to give cohesiveness to the liquid,'whereby a sharp, clear, dividing line, between the frosted and transparent parts of the bulb is obtained said 'powdered material settling in the etching parts where the material has settled.

2. A method of'frosting a portion of the inner surface of a glass bulb of an electric lamp; consisting in first injecting in the bulb a special etching liquid through a narrow tube and thereupon extracting said liquid therefrom; said liquid containing a powder selected from agroiip consisting of starch and cornflour, which acts to give cohesiveness answers