Glove box

The glove box has a rotatably supported bottom member (2, 11, 51) which is quipped with a number of product holders (14) positioned concentrically with the rotational axis of the bottom member. The product holders receive subassemblies or precursor products to be processed, partly within and partly without the glove box. Typical precursor products are discharge vessels for discharge lamps, of small size, for example having discharge vessel volumes in the tenths and hundredths of a cubic centimeter, which are to be flushed with a flushing gas, and then filled with an ionizable fill. Rotation of the bottom member delivers the products in the product holders to work-stations at which flushing, filling and other operations are carried out inside the glove box. Simultaneously, other operations such as pinching and sealing portions of the discharge vessels can be carried out outside of the glove box by suitable outwardly located operating stations (18). The bottom member is rotated in synchronism with the cadence or operating cycles of the respective operating stations. This permits simultaneous processing of the products within the glove box in a protective gas atmosphere while also operating thereon outside of the glove box.

FIELD OF THE INVENTION. 
The present invention relates to a glove box to contain a protective gas 
atmosphere. More particularly, the invention relates to a glove box in 
which gas discharge lamps, for which extremely high demands are made in 
terms of filling purity, are supplied with an ionizable filling. 
BACKGROUND 
When manufacturing low-wattage high-pressure discharge lamps on a 
lamp-making machine, the ionizable filling must be introduced into the 
discharge vessel with particular care. Because low-wattage high-pressure 
discharge lamps have relatively small discharge volumes and 
correspondingly small metered amounts of filing components, even slight 
contamination of the discharge volume can affect the light output of the 
lamp or can even cause the lamp to fail. Thus, flushing and filling 
processes carried out with a conventional pump stand of the type used for 
other gas discharge lamps, entail considerable risks. 
The production of sodium high-pressure discharge lamps is typically carried 
out for the most part inside a glove box in a protective gas atmosphere. 
For processing, precursor products or subassemblies, the sodium 
high-pressure discharge lamps themselves are fed in batches to the 
interior of the glove box through one or more gates. Tools are located in 
the interior of the glove box for processing and/or working on the lamps 
and/or the lamp precursor products. These tools or the work-stations are 
interrelated by a transport system for the lamps and/or lamp precursor 
products. They are highly automated in order to provide high output. 
This technology, however, cannot readily be adapted to the manufacture of 
other high-pressure discharge lamps, such as mercury vapor high-pressure 
discharge lamps or halogen metal vapor high-pressure discharge lamps, 
since some of the production steps required for these lamps, such as 
sealing off the ends of the discharge vessels and freezing out the noble 
gas filling component, can be accomplished in a glove box only at very 
high and hardly acceptable technological effort and expense. 
Moreover, the high degree of automation of the procedures within the glove 
box may lead to a slight contamination from dust, abrasion, and lubricant 
vapors, which contamination can no longer be tolerated in the manufacture 
of discharge lamps having extremely small discharge volumes down to 0.03 
cm.sup.3 and correspondingly small amounts of metered filling components. 
Such lamps are used, for example, as low-wattage high-pressure discharge 
lamps in motor vehicle headlights. On the other hand, if a high throughput 
capacity is to be attained, it is impossible to dispense with the high 
degree of automation of the procedures even in the manufacture of 
low-wattage high-pressure discharge lamps. 
THE INVENTION 
Accordingly, it is an object of the present invention to provide a glove 
box that is usable for manufacturing products, especially electric lamps, 
in which high demands are made on the purity of the protective gas 
atmosphere in the interior of the glove box, and which provides a high 
output or throughput capacity or capability. 
Briefly, the glove box according to the invention has side parts and at 
least one top part and a bottom member that is rotatable about a, 
preferably rotatable, axis. The bottom member, the side parts, and the at 
least one top part are connected together to form a gas-tight sealed 
interior which contains a protective gas atmosphere. A number of product 
holders are secured to the bottom member for retaining precursor products 
or subassemblies or semi-finished products that are to be processed. Each 
of the product holders has a duct that can be closed in a gas-tight 
manner. 
The product holders are arranged along a circle or a circular arc, that is 
concentric with the rotational axis of the bottom member. The product 
holders retain the precursor products or the semi-finished products such 
that one subregion or partial region, or portion of the precursor products 
or of the semi-finished products is accessible to processing devices 
located inside the glove box in the protective gas atmosphere. 
At the same time another subregion or portion of the precursor products or 
semi-finished products is accessible to tools or work-stations located 
outside the glove box. 
This arrangement makes it possible to perform inside the glove box only 
those procedures that absolutely must be carried out in a protective gas 
atmosphere, while all remaining production steps can take place outside of 
the glove box. Thus, only the processing devices or work-stations required 
for carrying out the procedures that take place in the protective gas 
atmosphere need be mounted in the interior of the glove box, while all the 
remaining tools or stations can be arranged outside of the glove box. This 
arrangement considerably reduces any contamination which might occur in 
the glove box protective gas atmosphere. 
The glove box according to the invention permits that the precursor 
products or semi-finished products to be processed no longer need to be 
fed into the interior of the glove box in batches. Additionally, the glove 
box of the present invention does not require transport systems in its 
interior for the precursor products or semi-finished products to be 
processed. 
The processing devices, work-stations and/or tools are located above and 
below the circle or arc defined by the product holders, so that when the 
glove box bottom rotates in synchronism with the operating rhythm, or 
cadence, or cycle of the processing devices and tools, the precursor 
products, subassemblies or semi-finished products retained in the product 
holders are supplied directly to the various processing devices or 
stations and tools. This makes it possible to achieve a very high 
throughput. 
Preferably, the bottom member of the glove box is sealed with an annular 
seal that has dry slide bearing segments that are pressed against the 
bottom member of the glove box. The required contact pressure is 
generated, in one embodiment, by an inflatable annular hose located in the 
glove box wall, above the seal. It is also possible to generate the 
necessary contact pressure in other ways. For example, in a second 
embodiment, the requisite contact pressure is assured with the aid of 
roller blocks, which precisely position the relatively movable elements, 
that is, the bottom member of the glove box and the hood of the glove box, 
with respect to one another. 
The seal itself is provided with a circumferential barrier channel that is 
flushed with inert gas, to prevent air from diffusing into the interior of 
the glove box. The gas pressure inside the glove box is advantageously 
slightly above the air pressure prevailing outside the glove box, so that 
invasion of air and other contaminants into the interior of the glove box 
is made difficult.

DETAILED DESCRIPTION 
FIG. 1 illustrates the basic principle of the glove box according to the 
present invention in a highly schematic form. The glove box has a hood 1 
with a top part 1a and a side part 1b, and a rotatably supported bottom 
member 2. The bottom member 2 is equipped with a number of product holders 
3 for retaining precursor products 4. The precursor products 4 shown are 
discharge vessels of low-wattage high-pressure discharge lamps. The upper 
end of the discharge vessel 4 is located in the interior of the glove box 
1 in a protective gas atmosphere, so that the discharge volume 
communicates with the protective gas atmosphere, while the lower end of 
the discharge vessel 4 is located outside the glove box 1. 
The introduction of filling components can now be carried out in a 
protective gas atmosphere by utilizing processing devices or operating 
stations mounted inside the glove box. By rotating the bottom member 2 of 
the glove box in synchronism with the operating cycles of the lamp-making 
machine, the discharge vessels 4 retained in the product holders 3 are 
delivered to the various processing stations and their tools inside and 
outside the glove box 1. A seal 5a, 5b of the bottom member 2 of the glove 
box has double walls that define an annular barrier channel 6 with is 
flushed with inert gas 7. 
FIG. 2 is a more detailed side view, partly in section, of a glove box 
according to the present invention. This glove box includes a hood 10 
having top parts 10a, 10a' and side parts, 10b, as well as a bottom member 
11. The hood 10 and bottom 11, together define a sealed gas-tight interior 
12. The glove box interior 12 is accessible for manual manipulations by 
gloves 21 that are joined in a gas-tight manner to the side part 10b and 
protrude into the interior 12 of the glove box. 
The glove box bottom member 11 is a circular disc. It is supported so as to 
be rotatable about its vertical axis via a ring 11a. The diameter of the 
bottom 11 is approximately 110 cm. An annular seal 13 is arranged between 
the edge of the bottom member 11 and the side part 10b of the hood 10. 
Twenty-four product holders 14 are mounted on the bottom member 11, 
equidistantly spaced along a circle extending concentrically with the 
vertical axis of the bottom member. Each of the product holders 14 retains 
a discharge vessel 15 of a high-pressure discharge lamp. 
The top part 10a of the hood is located parallel to the bottom member 11 of 
glove box and serves as a mounting platform for processing devices 16, 
shown only schematically, which are mounted in the interior 12 of the 
glove box. These processing devices 16 are located above the product 
holders 14 along the circle defined by the product holders 14. A second, 
stationary mounting platform 17 is located below and parallel to the 
rotatable bottom member 11 of the glove box. The second mounting platform 
17 is equipped with work-stations and tools 18 which are used for 
processing the discharge vessels 15 outside interior 12 of the glove box. 
These work-stations 18 carry out such production steps as heating or 
pinching of the discharge tube vessel ends, for example, whereas the 
processing devices 16 within the glove box interior 12 have the task of 
introducing the filling components into the discharge volume. The bottom 
member 11 of the glove box rotates in synchronism with the operating 
cycles of the processing devices 16 and the stations and tools 18 so that 
the discharge vessels 15 retained in the product holders 14 are delivered 
in succession to the devices 16 and the stations and tools 18 at the 
various processing stations. 
The interior 12 of the glove box contains an argon atmosphere, whose gas 
pressure is slightly above the air pressure external to the glove box in 
order to prevent the incursion of air or other contaminants into the glove 
box. The argon undergoes a circulation process in which it is delivered to 
the glove box interior 12 from an argon cleaning system R via a supply 
line 19 mounted axially in the top part 10a of the hood 10. The argon is 
returned to the argon cleaning system R via suction removal devices 20 
mounted eccentrically in the top part 10a. This arrangement, on the one 
hand, creates a radially outward-oriented flow in the interior 12 of the 
glove box and, on the other hand, flushes the sealing region 13 with argon 
so that a diffusion of air inward is prevented. The course of the flow is 
represented by arrows in FIG. 2. 
Details of the seal 13 and the product holder 14 will next be described in 
connection with FIG. 3. 
Construction of the seal of FIG. 3 
The seal 13, in a first embodiment, has a sealing ring 13a having a 
U-shaped cross section which has two concentric annular sealing faces. The 
seal 13 further includes an inflatable annular hose 13b and dry slide 
bearing segments 13c which are adhesively bonded to the sealing faces. The 
hose 13b can be inflated by compressed air L and the sealing ring 13a, 
with the dry slide bearing segments 13c, is pressed against the bottom 
member 11 of the glove box. The dry slide bearing segments 13ccomprise 
polytetrafluorethylene, known as TEFLON.RTM. or a 
vinylidene-fluoride-hexafluorpropylene copolymerizate, known as 
VITON.RTM.. If slide bearing segments for seal 13 are made of VITON.RTM. 
they should also be lubricated with high-vacuum grease. The U-shaped 
sealing ring 13a and a recess in the bottom member 11 of the glove box 
define a barrier channel 22, which is flushed with argon through a tube 
22a. Argon is introduced through tube 22a, and leaves than channel 22 
through a duct 22b. The bottom member 11 of the glove box and the lower 
portion 10a of the top part of the hood, acting as a mounting platform, 
are equipped with overlapping partitions 29, 30 that extend parallel to 
the side part 10b of the hood and shade off the sealing region from the 
remaining interior 12 of the box. Any gaseous contaminants that may have 
entered through the seal 13 are carried off here, together with the argon, 
by the suction removal devices 20 to the argon cleaning system R. 
The product holders 14 are screwed to the bottom member 11 in a gas-tight 
manner. The product holders 14 have a cylindrical duct 23, which pierces 
the bottom member 11 of the glove box and is equipped with a tightenable 
sealing ring 24. The tubular extension of the discharge vessel 15, which 
is fixed in a mounting frame 25, is retained in a gas-tight manner in the 
duct 23 so that the discharge volume of vessel 15 can communicate with the 
interior 12 of the glove box. The opening of the duct 23 toward the glove 
box interior 12 is connected, as shown on FIG. 3 in a gas-tight manner to 
a flushing channel 26 of an argon flushing device 27, shown only 
schematically, which serves to flush the discharge volume. Flushing device 
27 is coupled to the rotary bottom 11 by a suitable rotary joint as well 
known in the art, or could be similar to seal 13. The flushing channel 26 
is secured to a frame 31 and can be removed from the product holder 14 by 
lifting and rotating the frame 31, so that the filling components and the 
upper electrode system can be introduced into the discharge vessel 15 from 
the glove box interior 12. 
Construction of the seal of FIG. 4 
FIG. 4 shows a cross section through a second embodiment of a seal of the 
glove box. This second embodiment differs from the first embodiment of the 
glove box seal only by the seal of the bottom 51 of the glove box which 
corresponds, generally, to plate 2, FIG. 1, or plate 11, FIGS. 2 and 3. 
The seal, in this embodiment, includes an annular sealing element 40, which 
is screwed to the side parts 52a of the glove box hood 52 via a rubber 
plate 41. Hood 52 corresponds to hood 10, FIG. 2. The sealing element 40 
rests on two TEFLON.RTM. sealing rings 42a, 42b, which are concentric to 
the vertical rotational axis (not shown in FIG. 4) of the bottom member 51 
of the glove box. The sealing rings 42a, 42b are screwed to the bottom 
member 51 of the glove box by a plurality of fasteners 43 so that, upon 
rotation of the bottom member 51 of the glove box, the sealing element 40 
slides on the TEFLON.RTM. sealing rings 42a, 42b. The two sealing rings 
42a, 42b, together with the bottom member 51 of the glove box and the 
sealing element 40, form an annular barrier channel 44, which is flushed 
with inert gas, preferably argon, via openings 45 in the bottom member 51 
of the glove box. 
The bottom member 51 of the glove box and the annular sealing element 40 
sliding on the TEFLON.RTM. rings 42a, 42b are positioned precisely 
relative to one another by a number of roller members 46, 47, 48, which 
are secured to the sealing element 40. Roller member 48 is 
circumferentially offset with respect to roller members 46, 47. Two 
overlapping partitions 49, 50 shield the sealing element 40 from the 
interior of the glove box. One of the partitions 49 is secured to the side 
part 52a of the glove box hood 52, and the other partition 50 is fixed to 
the bottom member 51 of the glove box. 
The invention is not limited to the embodiment described in detail above. 
For instance, it is possible in the second embodiment to secure the 
TEFLON.RTM. sealing rings 42a, 42b to the sealing element 40, instead of 
to the bottom 51 of the glove box so that the bottom member 51 of the 
glove box slides on the sealing ring 42a, 42b. Moreover, the external 
shape of the glove box and in particular the shape of the glove box hood 
10, 52 can have virtually any desired shape. For instance, it can be 
box-shaped or cylindrical in form.