Untitled record

TSR MEER - MÜLLER ^ f liÜMEß3? I = k; & f ^ R-fώφ Deutsche Metrohm

= 3 Δ ϋ

ιηβοη v? erdsn _._

Measurements of the chemical oxygen demand (COD) of water samples by titration.

Titration devices are known in which the titration takes place directly in the sample vessels. For this purpose, the sample containers are arranged in a circle on a turntable of a sample changer. By stepwise drive of the turntable, the sample vessels with the samples contained therein are successively fed to a titration station in which the titration liquid passes, the course of the reaction is monitored by means of measuring electrodes introduced vertically into the sample vessels, and then the titrated solution is aspirated.

Sample preparation or reagent dosing must take place under defined conditions, in particular at a certain temperature. Therefore, in the conventional titration apparatus, the sample vessels are individually detachable from the sample changer and set in a thermostat, so that the samples can be heated to the desired temperature or cooled.

The implementation of the sample vessels from the sample changer in the thermostat and vice versa j edoch but relatively complicated in conventional devices and also represents a not inconsiderable source of danger_r there the

BES

1

CHREiBUNO,

The invention relates to a device for the chemical examination and / or treatment of substances contained in a plurality of sample vessels according to the preamble of claim 1.

TI = R sea - MPLLER

Look, Metröhm

Open sample vessels often very aggressive solutions, such as concentrated sulfuric acid in the case of COD measurements included.

The invention is therefore based on the object to simplify the handling of the sample vessels in a device of the type mentioned and to increase the safety at Arheiten with the device.

The achievement of this object of the invention results from the characterizing part of claim 1.

The basic idea of ​​the invention is that all sample containers are arranged in a common sample holder, which is mounted rotatable and detachable on the turntable of the sample holder, so that all samples can be handled with the sample holder as a unit and used, for example, in the thermostat.

Advantageous developments and refinements of the device according to the invention are specified in the dependent claims.

In the following preferred embodiments of the invention will be explained in more detail with reference to the drawings.

30 35

Show it:

Fig. 1

Fig. 2

a perspective view of a titration device according to the invention;

a sample holder in plan view; and

TER MEER - MÖLLER <

DeUtsohe Metiiohm

3 is a schematic section through a sample changer with attached sample holder *

FIG. 1 shows a complete titration device with a sample changer 10 which carries a number of circularly arranged sample vessels 12, a titration station 14 arranged at the circumference of the sample changer, a dosing unit 16 for supplying titration liquid to the titration station, a pump 18 for sucking off the titrated Solution and for rinsing the sample vessels, a thermostat 20 and a controller 22nd

The sample changer 12 has a step-wise driven turntable 24, through which the sample containers 12 are successively fed to the titration station 14.

The titration station 14 has a carriage 28 which can be moved vertically along a column 26 and carries a number of measuring electrodes 30 and probes 32 for supplying and aspirating liquid. The measuring electrodes and probes can be inserted by lowering the carriage 28 into the respective sample vessel 12 located at the titration station.

The turntable 24 has a base plate 34 and a central cylindrical pedestal 36, on which a disk-shaped sample holder 38 is mounted rotatably. The sample holder 38 has a number of receiving openings 40 (FIG. 2) for the individual sample containers 12 in the vicinity of its outer edge. Each receiving opening is surrounded by a sleeve-shaped guide member 42 through which the substantially cylindrical ProbengefSS ^ t-- il is held.

The sample holder 38 is from the base 36 of the turntable

TER sea - möller - Js-felNMdlSTERÄ ^ Kx ^^ R Deutsche Metrohm

removable and is again shown separately in Figure 1 above the thermostat 20. For handling the sample holder 38, in the embodiment according to FIG. 1, a handle 44 fastened in the center of the disk-shaped sample holder is provided.

The thermostat 20 serves to heat or cool the samples to the particular desired reaction temperature and has a heatable metal block 46 which is provided with a number of receiving wells 48 for the individual sample vessels 12. The arrangement of the receiving wells 48 in the metal block 46 is consistent with the arrangement of the sample vessels 12 in the sample holder 38. With the help of the sample holder 38 thus all the sample vessels 12 can be removed together with a handle of the sample changer 10 and used with their exposed lower portions in the receiving wells 48 of the thermostat. When the desired curing temperature has been reached, the sample containers can be placed in the same way again with a single handle on the turntable of the sample changer. In this way, the handling of the sample vessels is greatly simplified and reduces the risk that when handling the individual sample vessels corrosive or flammable liquid is spilled. In addition, a higher accuracy of measurement is achieved because the samples can be transferred by means of the sample holder 38 in the shortest possible time from the thermostat in the sample changer, so that it is possible to comply more accurately with the reaction temperature.

As can be seen in Figures 2 and 3, has the disc-shaped sample container 38 in his Mitteiiber.eich three PösitiönieiföffnUngen SCl / 52 aü_e in the Von der¹ Öbetff¹ Let 3S of the pedestal 36 of the turntable bear identical malting pins 64

Il ti If I Il iiü ·>

t- f I »II Il KM

TER MEER - möller -'STtlNMÖStdR. & PARTNER German Metrohm

· * 1 * ■ * t .HII '' t

9 rr 9

engage, so that a rotationally fixed connection between the sample holder 38 and the turntable 24 is provided. The retaining pins 54 have a shoulder for supporting the sample holder 38 and are tapered at its upper end, so that the placement and centering of the sample holder is facilitated. The positioning hole 50 and the associated retaining pin have a slightly smaller diameter than the remaining positioning holes 52 and retaining pins. This ensures that the sample holder can be put on the turntable 24 only in a certain angular position.

The receiving openings 40 for the sample containers 12 are distributed at uniform angular intervals on the circumference of the sample holder 38. At one point of its circumference, however, the sample holder has a recess 56, which occupies the position of a missing centering opening. When the turntable 24 is in its home position, the recess 56 faces the titration station 14. Therefore, even when the carriage is in its lowered position, the sample holder 38 can be put on and taken off without damaging the probes and electrodes. In addition, a protective tube 58 is installed on the turntable 24, which corresponds in shape approximately to the sample vessels 12 and is received in the recess 56 when the sample holder 38 is mounted. When the turntable is in the home position and the carriage 28 is lowered, the probes 30 and electrodes 32 therefore dip into the protective tube 58, so that they are additionally protected against damage.

As can be seen in Figure 3, each of the Führünggehülsen 42 for¹ project the sample vessels 12 with a downward projection

• I ti Il I Il HK «I

«Tieiti ti ··!

* t Ht ItIf II * I

I 4 · 4t III III · I

jo

_mm aft »·« * ·

TER MEER - möller irs ^ EJNMEISTER.fi, PAFjTtv ^ R Deutsche Metrohm

-B-

boom provided 60 which is angled at its lower end and engages under the bottom of the sample vessel, so that the sample vessel is secured in the vertical direction. When the sample holder 38 is placed on the thermostat 20, the boom 60 are inserted into the receiving slots 48.

Finally, FIGS. 2 and 3 illustrate a modified embodiment of handles for handling the sample holder 38. According to this embodiment, two bow-shaped handles 62 are provided, which can be hooked with their hook-shaped upwardly bent ends 64 into corresponding insertion openings 66 on the circumference of the sample holder 38.

15

The sample holder 38 not only allows a considerable Arbeitserleijhungung when converting the sample containers from the sample changer 10 in the thermostat 20 and vice versa, but also allows all sample vessels easily and safely use in several identical sample changer, so that in complex analysis operations, the multiple titration steps, Dosing steps and the like include, can be worked in a rational way with multiple sample changer for the various process steps.

I 41 ti i H ttI I ·

* II f III · · <

6 i It tlltl Ml * ·

«Ii ti ti * t«