Arrangement for cleaning a container testing apparatus

On a bottle testing apparatus which has a plurality of sampling tubes which can be lowered into the bottles, the said tubes are individually detachable for cleaning. Hence they can be quickly and easily replaced with clean tubes. In addition, an adaptor is provided by means of which a cleaning fluid can be passed through the pipes of the apparatus.

BACKGROUND OF THE INVENTION 
The invention relates to processes for cleaning a container testing 
apparatus having gas sampling elements which can be lowered into the 
containers and a distributor device for successively dispensing the gas 
samples withdrawn from the containers to an analyzing instrument. The 
invention also relates to a container testing apparatus with a plurality 
of sampling elements which can be lowered into the container and an 
arrangement for cleaning a container testing apparatus having a stationary 
distributor head part and a moving distributor head part and pipes leading 
from said moving part to sampling elements which can be lowered into 
containers for testing. 
With returnable bottles, in particular with plastic bottles, such as PET 
bottles, which cannot be washed at high temperatures, the problem arises 
that contamination must be reliably detected in order that contaminated 
bottles can be removed and/or diverted from refilling. In particular, it 
is necessary to be able to detect returned bottles which have been used by 
individual users for potentially dangerous substances (poisons, solvents). 
It is an already known procedure to take a gas sample from each bottle for 
this purpose and to analyse the sample by a suitable method, e.g. by 
photoionization detection (PID) or mass spectroscopy. The presence of even 
small traces of undesired substances in the bottle and/or in the plastic 
material can be detected in this way. Industrial testing apparatus with a 
high bottle throughput (of e.g. 250 to 700 bottles per minute) which test 
the bottles in this manner are available on the market. 
It has been found that the cleaning of a testing apparatus of this kind, 
possessing a large number of sampling tubes for withdrawing the gas 
samples, is a laborious process involving relatively extended stoppage 
times. Nevertheless frequent cleaning is necessary in order that sensitive 
detection of foreign substances can actually be achieved. 
SUMMARY OF THE INVENTION 
The invention therefore addresses the object of facilitating the cleaning 
of container testing apparatus. This is achieved by the process in which a 
cleaning medium is passed through the distributor device by means of an 
adaptor mounted on the distributor device, and the gas sampling elements 
are at least partially dismantled and cleaned separately and also, with 
the container testing apparatus in which the sampling elements each 
comprise a sampling tube which is attached in such a manner that it can be 
released without the use of a tool and with the arrangement having an 
adaptor part which can be mounted on the container testing apparatus in 
place of the stationary distributor head part. The adaptor part has a 
connection for supplying at least one fluid and a channel which is in 
communication with the connection and which, when the adaptor part is 
fitted, is in communication with at least some of the pipes via the moving 
distributor head part. 
According to a first aspect of the invention, the object is attained by 
providing each of the sampling units with a releasably attached sampling 
tube. 
This makes it possible to separate the sampling tubes from the testing 
apparatus for cleaning purposes, and to fit precleaned and therefore 
uncontaminated sampling tubes, within an extremely short time. The 
sampling tubes which have been removed can then be cleaned without time 
pressure, and hence thoroughly, and are then available for the next 
changeover. This in itself enables the cleaning of sampling tubes, and/or 
the fitting of clean tubes, to be carried out every 2 to 3 days without 
long and costly stoppages. 
In accordance with a further aspect of the invention, the object is 
achieved by an arrangement for cleaning a testing apparatus which allows 
simple cleaning of the parts connected to the sampling tube which conveys 
the gas to the testing instrument. 
This arrangement allows simple flushing and drying of the principal pipes 
and passageways of a testing apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows part of a bottle testing apparatus which is constructed e.g. 
in the form of a conveyor carousel carrying a large number of bottles. In 
FIG. 1, only part of one bottle 1 is indicated in chain-dotted outline. 
Above each bottle holder position on the carousel, a sampling tube 2 for 
withdrawing gas from the bottle 1 is mounted on a movable slide 6. In FIG. 
1 the slide 6 is shown with the sampling tube 2 dipping into the bottle 1 
for the withdrawal of gas. In an upper slide position, represented at 6' 
by a fragmentary view of the top of the slide, the sampling tube 2 is 
lifted out of the bottle 1. Movement of the slide is effected e.g. by 
means of a cam against the action of a spring. It is of course also 
possible to move the bottle rather than the sampling tube. When the bottle 
1 enters a respective holder on the carousel, the slide is in its upper 
position. The slide together with the sampling tube is then lowered and 
gas is withdrawn from the bottle 1 while the latter remains in the 
carousel. The withdrawn gas passes via a hose 8 to a distributor head 
which successively switches the gas withdrawn from the bottles present in 
the carousel, as individual gas samples, to one or more analysing 
instruments. When the bottle has completed its time in the carousel, the 
slide 6 is raised to the position 6' and the bottle leaves the carousel. 
The corresponding bottle holder is then able to receive another bottle. 
In this instance the sampling tube 2 is releasably attached to a holder 4,5 
which is fixed to the slide. The releasable attachment, e.g. by means of a 
cap nut 3, enables each sampling tube to be rapidly released from the 
slide 6 and replaced with a clean tube 2. As a result, the down time for 
the testing apparatus is short. The tubes 2 which have been released can 
then be cleaned at leisure. 
FIG. 2 shows a gas sampling tube 2 and its attachment to the holder 5 on 
the slide extension arm 4. The gas sampling tube 2 has an outer, generally 
cylindrical, sleeve 12. The actual extraction tube 10 for the gas is 
arranged inside this sleeve 12. The extraction tube 10 is coupled to a 
flexible pipe 14 which extends inside the hose 8 and which conveys the gas 
to the distributor head. 
The extraction tube 10 is permanently fixed inside the gas sampling tube 2 
and is replaced along with it. The extraction tube is attached by being 
fixed in an end spigot 13 which is connected to the sleeve 12, e.g. by 
soldering, bonding, or welding. The tube 10 communicates with the pipe 14 
via a bore 15 in the spigot 13. An air injection tube 9 is also fixed 
inside the sampling tube 2 by means of the end spigot 13 attached to the 
sleeve 12. To assist the withdrawal of a representative gas sample, air is 
blown into the bottle 1 through a pipe 14' in the hose 8, which 
communicates with the tube 9 in the spigot 13 via a bore 15' in the spigot 
13 which is common to the pipe 14' and to the tube 9. Hence the tubes 9 
and 10 are removed together from the holder 5 along with the sleeve 12. 
The gas sampling tube 2, comprising the sleeve 12 and the tubes 9,10, is 
attached to the holder 5 by means of a cap nut 3 which is preferably 
arranged to be tightened and loosened without the use of a tool. This cap 
nut engages with a peripheral flange of the spigot 13 connected to the 
sleeve 12. When the cap nut 3 is tightened on the holder 5 to secure the 
gas sampling tube 2 to the slide 6, a rubber seal 11 which projects from 
the holder 5 is compressed by the end face of the spigot 13. 
The sampling apparatus also contains a heater element (which is not visible 
in FIG. 2 since it lies behind the tubes 9,10) to prevent condensation, 
especially on the extraction tube 10. This heater element is preferably 
permanently installed in the holder 5 and/or slide extension arm, and is 
not replaced along with the individual sampling tube. However, space is 
provided in the sampling tube for this heater element, which is usually in 
the form of a rod, and the spigot 13 has a corresponding bore to enable it 
to pass through. 
FIG. 3 shows a further part of the testing apparatus, with the 
abovementioned distributor head 16, located on the central axis of the 
carousel in this example. The distributor head comprises a rotating part 
17 and a stationary part 18. The rotating part 17 is mounted on and is 
moved with the carousel. These parts are pressed together by a central 
pressure bell 32. In FIG. 3A, the parts 17,18 and 32 have been exploded 
and partially cutaway for the sake of clarity. Connected to the rotating 
part 17 are the individual pipes which are combined inside the hose 8 in 
FIG. 1, namely in each case the pipe 14 conveying the gas sample to the 
distributor head and the pipe 14' conveying compressed air to the bottle. 
Inside the distributor head 16 all the gas samples are drawn through a 
central suction pipe 21, one of the gas samples in each case passing via a 
pipe 19 to the analysing instrument, e.g. to a mass spectrometer. For this 
purpose, the stationary part 18 of the distributor head contains an 
annular channel 22 which is interrupted at one point. An isolating 
passageway 23 is provided at this point. All the pipes 14 except one are 
in communication with the channel 22. A single pipe at the position 
indicated by the reference 14" is in communication with the passageway 23 
at any given time, and the gas sample from the pipe at this position 
passes into the pipe 19 and thence to the analysing instrument. As the 
moving part 17 rotates, each pipe 14 arrives in succession in the position 
14" in FIG. 3, so that each gas sample passes separately and in succession 
to the analysing instrument. 
FIG. 4 shows the lower part of the distributor head in partly cut-away 
representation, the same elements being designated by the same reference 
symbols as in FIG. 3. Above the moving part 17 of the distributor head, an 
adaptor 24 which can be screwed onto the part 17 is shown in an as yet 
unconnected position. The connection may be made by means of the screw 26. 
The adaptor is used when cleaning the pipes 14 and the moving part 17, 
with the carousel stationary. For this purpose the adaptor 24 has a 
connection 27 to which a pipe supplying cleaning fluid under pressure or 
compressed air can be connected (this pipe is only schematically 
represented in the drawing). An electrically driven pump 30 (likewise only 
schematically represented) and a cleaning fluid tank 31 supplying this 
pump are for example provided for this purpose. Instead of the cleaning 
fluid, compressed air from a line 29 can be fed to the connection 27 via a 
two-way valve 28. 
On its surface facing the moving part 17, the adaptor has a channel 2B 
through which the cleaning fluid, or compressed air as the case may be, 
can be conveyed to all pipes 14. In this case, the channel 2S is circular. 
Alternatively, a semicircular channel 25 may be provided. In this case, 
the adaptor must be mounted a second time after being rotated through 
180.degree.. The advantage of the semicircular arrangement is that 
containers (bottles) need to be placed at only half the carousel positions 
to catch the cleaning fluid, which may be advantageous for reasons of 
accessibility, and the number of containers required. 
Cleaning with the adaptor results in quick and thorough cleaning of all 
major parts. Such cleaning may for example be carried out at monthly 
intervals. A further advantage of this method of cleaning is that when 
cleaning fluid is being forced through the system under pressure and/or 
when compressed air is subsequently connected, escapes of cleaning fluid 
or cleaning fluid/compressed air mixture make it possible to pinpoint 
leaks which are difficult to detect in operation (when surrounding air is 
sucked in). Accordingly, the adaptor can also be used at other times for 
detecting any leaks which may be present.