FR2524641A1 - Appts. to prepare samples of water e.g. from treatment plant - by adsorption on column packing for subsequent elution and analysis - Google Patents

Abstract

Appts. for automatically preparing samples for testing the quality of water. Different constituents for analysis are extracted from the water by fixing them on a support medium for subsequent elution and analysis. The appts. comprises a column contg. a packing which adsorbs a constituent as the water percolates continuously through the packing after being mixed with reagents. The mixt. overflows from a tank supplied with the water and the reagents, the overflow being channeled into the top of the column. The appts. is for the automatic prepn. of water analysis samples, partic. to test the quality of output from a water treatment plant, e.g. for microorganisms. The prepn. proceeds continuously partic. on site, rather than in batches sent to a laboratory. Risk of polluting a sample is minimised by avoiding the use of piston or peristaltic pumps. Even the solenoid valve is located downstream of the extd. samples.

Description

 The present invention relates to an apparatus for the preparation of samples intended for the control of the quality of any water, sea water for example, and more particularly for the control of the quality of water treated in a treatment station for waters.

 More specifically, the invention relates to water analysis devices comprising, in known manner, means for taking desired quantities of samples to be checked, means for extracting from these samples the constituents to be assayed such as organic compounds or minerals ,. microorganisms, viruses, etc. by fixing them on suitable supports, for example sand, activated carbon, resins, glass, etc., under specific operating conditions obtained by adding reagents, these constituents then being eluted from their supports respective and dosed.

 It is in fact advantageous to concentrate by extraction the constituents to be dosed in order to facilitate their subsequent analysis.

 The devices for preparing samples for the control of the quality of water currently designed for processes of this kind generally operate batchwise, by taking samples transferred to the laboratory and brought to percolate through a series of containers containing the supports suitable with addition of reagents also batchwise.

 These devices have several drawbacks. They require water storage, helping pollution risks. In addition, all operations being manual and discontinuous, require constant monitoring.

 However, the automation of such devices turns out to be difficult to control the water that must not be contaminated by pollutants during operations. Thus the use of piston dosers or peristaltic pumps for example for supplying the device and the addition of reagents is completely excluded; similarly, the presence of solenoid valves on the supply circuit would cause pollution risks.

 The apparatus for preparing samples intended for the automatic control of the quality of water, object of the invention, overcomes these various drawbacks by allowing extraction by fixing on a support in better conditions by reducing the maximum the risk of pollution, particularly in the supply system. In addition, it operates continuously and is perfectly suited for use in the field.

 The apparatus for the automatic preparation of samples intended for the automatic control of the quality of water, according to the invention, by extraction of the various constituents to be assayed, these constituents being fixed on at least one support to be subsequently elected and analyzed , is characterized in that this tool comprises at least one column containing a layer of support material intended to fix the constituents to be dosed, through which or which, is caused to percolate continuously strip to be analyzed, this column or these columns being supplied (s) by an overflow device receiving the water to be analyzed and the reagent or reagents necessary for the extraction of the constituents to be dosed, the supply of this overflow being itself regulated as a function of the amount of water flowing through the column.

 The supply of water and reagents to the overflow is regulated by means of a solenoid valve placed on the column's water outlet circuit, connected to the latter by means of a two-way control system. electrodes determining the high and low levels of the reactive water mixture in the column and connected via the same control system to a means, such as an air pump ensuring the supply of the overflow vessel with reagent (s).

 The column (s) is made or. are made of chemically inert plastic, preferably e'Teflon "; they are stackable, removable and interchangeable. This modular design of the columns allows elution in series or separate from the different supports, with the appropriate solvent. is thus easily usable in the field or in a factory not equipped with analytical equipment, the transport of the columns alone can easily be carried out towards a laboratory where the elution and analysis operations are carried out.

 The description which follows, with reference to the single appended drawing, will allow a better understanding of the invention.

 The single figure shows schematically an apparatus according to the invention in an embodiment comprising two superposed columns and the use of two reagents. Any other arrangement of columns of the same type, in series for example, with the addition of other reagents, but having the same single regulation device, can be envisaged without departing from the scope of the invention.

 The apparatus consists of two superimposed columns 1, la, each containing a different support 2, 2a, for fixing two different types of constituents to be extracted. The sample of water to be analyzed, the volume of which can range from one liter to several hundred liters, arrives via the tube 3 at a flow rate regulated by a regulation system 4 of known type, in the overflow device 5 supplying the extraction colols. In this overflow also arrive the reagents from the bottles 6, 6a. The water-reactants mixture flows in column 1 through the tube 7, passes through the support 2 and passes through the column 1a through the perforated separation wall 8 made for example from sintered glass; it then crosses the support Za and leaves the column by the tube 9.On this tube is arranged the solenoid valve 10 also connected to the overflow of the overflow vessel 5 by the tube 11; Water comes out of the device through tube 12.

 The solenoid valve 10 is connected by means of a control system 13 known per se, on the one hand, to two electrodes 14, 15, arranged at different levels in column 1 and, on the other hand, to an air pump 16 connected to the reagent bottle 6> 6a by the capillary tubes 17, in 'Teflon "for example. When the low electrode 14 is drained, the control system 13 causes the solenoid valve 10 to close and the starting the air pump 16: the water rises in the overflow vessel 5 and passes by overflow into the tube 7 supplying the column.

Simultaneously the air pressure in the reagent bottles 6, 6a causes the reagents to arrive in the overflow vessel 5 at a flow rate regulated by the capillaries 17. When the water-reagent mixture reaches the upper electrode 15, the solenoid valve 10 opens and we return to the initial state.

 Thus, thanks to the arrangements according to the invention, the column or columns are continuously supplied with water and with reagents in well determined proportions.

 In the example described, the two columns are assembled by a ring 18 and provided with plugs 19, 20. Of course other arrangements could be adopted for the assembly of the columns without, in doing so, leaving the framework of the 'invention.

 The apparatus further comprises a device for counting the volume of water passed over the support material, consisting of a counter integrated in the control system 13 and connected to the electrode 15 detecting the high level of water in the column. One unit is counted each time the electro- 15 is covered. The water being admitted into the column when the low electrode 14 is dewatered, the volume of water passed over the column is determined by multiplying the figure indicated by the counter, by the known volume of the portion of column determined by the difference between the two electrodes 14 and 15.

Claims (6)

1 - Apparatus for the automatic preparation of samples intended for  central water quality by extraction of different constituents  ants to be dosed, these constituents being fixed on at least one material  support for later elution and analysis, characterized in  that it comprises at least one column (1, la) containing the material  support (2, 2a) through which the water is continuously percolated  to be analyzed after adding the appropriate reagent (s), this colon  ne or these columns being fed (s) by an overflow vessel (5) re  cevant said water to be analyzed and the reagent (s), the supply of this  overflow being itself regulated according to the quantity of the mé  water-reagent line crossing the column (s).  2 -Apparatus according to claim 1 characterized in that the supply  of the overflow supplying the column or columns, with a water mixture  reagents is regulated through a unique communication system  control (13) by means of a solenoid valve (10) connected to two electrodes  (14, 15) determining the high and low levels of the water-reagent mixture  in the column considered and also linked to a means such as  air pump (16) ensuring the metered addition of the reagent or reagents  in the overflow vessel. 3 - Apparatus according to claim 2 characterized in that the electro  control valve for the tropiplein vessel in water and in reagent (s)  arranged on the column's water outlet circuit. 4 - Apparatus according to any one of the preceding claims  characterized in that the columns (1, la) are stackable, daemon  tables and interchangeable and adapted to each other by means of  rings or the equivalent. 5- Apparatus according to any one of the preceding claims  characterized in that the superimposed columns are separated by  perforated sintered glass partitions. 6 - Apparatus according to any of the preceding claims,  characterized in that the single control system (13) comprises  a counter connected to the electrode (15), allowing the counting of the volu  me of water passed over the support material.