GB2128360A

GB2128360A - Multi-purpose cell

Info

Publication number: GB2128360A
Application number: GB08325384A
Authority: GB
Inventors: Wolfgang Schirmaier
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-10-09
Filing date: 1983-09-22
Publication date: 1984-04-26
Also published as: CH660632A5; IT8322866A0; FR2534377B1; GB8325384D0; FR2534377A1; IT1169817B; GB2128360B; IT8322866A1; DE3237563C1

Abstract

The invention relates to a multi- purpose cell for photometric and/or spectrometric measuring. It consists of an approximately U-shaped base body (1) which comprises on its inner sides numerous guide faces (2-8) which follow one another in the longitudinal direction at defined spacings and extend in the transverse direction and in which inlet and outlet windows (9, 10) may be optionally inserted. As a result of this many cell sizes may be covered by one base body (1). Moreover, this base body (1) may be combined with inlet and outlet windows of different types of glass. <IMAGE>

Description

SPECIFICATION Multi-purpose cell The invention is based on a multi-purpose cell for photometric and/or spectrophotometric measuring, the measuring chamber of which is formed by a base, two opposite side walls and two transverse walls which act as inlet and outlet windows and have parallel faces.

Cells of this type are used for the analysis of fluid organic substances in that the permeability thereof is measured by irradiation with light of a certain wavelength. In the case of highly absorbent substances the cell has to be formed such that the irradiated layer is very thin. The distance between the inlet and outlet windows of the cell is only 5 to 10 mm in this case. On the other hand, with substances with a low degree of absorbency, cells which have a large layer thickness and are correspondingly long in the irradiation direction have to be used. For this purpose the cells are divided into certain grille sizes with respect to their layer thickness.

In addition, the cells have to be produced from different types of glass since a different type of glass is provided for certain wavelength ranges in each case. There are thus, for example, cells of crown glass, flint glass, barytes glass and of various types of quartz glass. Therefore there always has to be a large number of very different types of cells kept at hand in the laboratory in order that the correct selection may be made, on the one hand, with respect to the thickness of layer and, on the other, with respect to the type of glass.

Taking this as a starting point, the object of the present invention lies in improving the cells of the initially mentioned type to the effect that they are more flexible in terms of their use, i.e. such that a particular type of cell does not have to be available for each grille size and each type of glass.

In accordance with the invention, this object is achieved in that the base and the side walls of the cell form an elongate base body which is approximately U-shaped in cross-section and comprises on its inner sides numerous depressions or projections which follow one another at a defined spacing in the longitudinal direction, extend in the transverse direction and act as guide surfaces for inlet outlet windows which may be optionaliy inserted.

The invention offers the possibility of using a uniform base body and inserting the inlet and outlet windows therein at the distance which corresponds to the desired thickness of layer of the substance to be examined and therefore numerous individual cells of varying layer thickness are no longer required, but instead all usual cell sizes are covered by a base body, an inlet window and an outlet window.

A further advantage of the invention lies in the fact that inlet and outlet windows of very different types of glass may of course be inserted in this base body such that a considerable simplification is also provided in this respect.

Finally, the dismountable cells also facilitate cleaning, in particular when the substances to be tested are highly adhesive.

The average person skilled in the art has many possibilities for the construction of the depressions or projections which follow one another at a defined spacing in the longitudinal direction in the manner of a grille, in the base body. In this connection, the only essential factor is that the inlet and outlet windows may be easily inserted and removed again, that the predetermined position is maintained and that the measuring chamber is sufficiently leaktight.

Advantageously, the inlet and outlet windows are inserted into the base body from above. It is also within the scope of the invention, however, to provide a base body whose inner cross-section decreases in a stepwise manner in the longitudinal direction, such that these steps act as guide faces for the windows to be inserted obliquely or laterally. With respect to manufacturing techniques, however, it is most favourable to provide the insertion guiding and the retention of the windows in the inserted state by forming the guide faces by means of grooves in the base body which pass around in the transverse direction.

In order to obtain adequate sealing, it is further recommended that the base body and/or the inlet and outlet windows comprise a seal on their opposite contact faces. If the guide faces are formed as circulating grooves, this seal may be in the form of resilient sealing lips arranged in the grooves. Evidently, there are also other possibilities for the sealing as also for the retaining of the windows; thus the windows, for example, may be guided accurately in the base body and simultaneously sealed by mechanical means, perhaps by springs or by a wedging.

It is particularly favourable with respect to manufacture if the base body is formed in one piece and consists of plastics material which is resistant to acid and to lye solution. In this connection, the sealing lips may be integrally formed automatically when the base body is injection moulded.

The principle described for changing the inlet and outlet windows whilst the base body remains the same may evidently also be used with cells which are provided with additional infeed, discharge or passage ducts or with tempering devices.

Further details and features of the invention result from the foilowing description of one embodiment with reference to the drawing, in which: Figure 1 shows a sectional view of the cell from above; Figure 2 shows a side view of this cell in section; and Figure 3 shows a side view of the cell viewed in the direction of irradiation.

The U-shaped base body 1 of the cell may be seen best in Figure 3. It consists of a base 1 a and two upwardly extending walls 1 b and 1 c. The base body 1 is open at the top and at the front and the rear (i.e. perpendicular to the plane of the drawing). Advantageously, the base body 1 is produced in one piece, in particular as a part injection moulded from plastics material resistant to acid and to lye solution. Its cross-sectionai shape, wall thickness and funnel-shaped widening at the upper end correspond to the usual standard dimensions, but may, of course, be altered within the scope of the requirements of use in each case.

In accordance with the invention guide faces, which extend in the transverse direction, are attached to the inner walls of the base body 1 and enable the base body to be closed both at the front and in its central or rear region by an inlet or outlet window which may be inserted from above.

In the embodiment these guide faces are formed by grooves 2 to 8 passing round in the transverse direction, as shown in Figure 1. The width and depth of these grooves are dimensioned such that in each case they are suitable for guiding and retaining in a leaktight manner an inlet window 9 or outlet window 10 which may be inserted from above. The distance of the grooves from one another is adapted to the usual standard values for the depth of layer of the substances to be examined. As a result of this, all common layer depths may be produced and a corresponding number of conventional individual cells may be replaced by a single base body. The various depths of layer are shown in the lateral section according to Figure 2.

In addition, inlet and outlet windows of the most different types of glass may be inserted in the base body 1. The multi-purpose cell according to the invention is therefore suitable for irradiations of all ranges of wavelength. Instead of complete conventional cells only the corresponding windows have to be available.

In order that the inlet and outlet windows may be easily inserted into the base body 1 from above and, nevertheless, that a good sealing is ensured, the grooves 2 and 8 comprise on one of their lateral faces in each case a plurality of sealing lips which lie adjacent one another and pass round in the peripheral direction. Advantageously they are integrally formed directly on the base body and are produced therewith. As a result of their resilience they enable the windows to be inserted without jamming whilst providing a good sealing effect.

It is essential that the sealing lips are always placed only on one side wall of the grooves. As a result thereof, the other side wall forms a defined abutment face for the windows and ensures their accurate, parallel position in the base body, i.e. the precisely predetermined depth of layer between the inlet and outlet windows.

It is evidently within the scope of the invention to provide optionally other sealing devices, for example resilient sealing strips placed in the side walls of the windows, or to press the windows in another manner against a guide face, acting as a reference face, in the base body. It is likewise within the scope of the invention to guide the windows in elevated portions, instead of in grooves in the base body, the windows in turn then comprising recesses adapted to these elevated portions. The only crucial factor is that the guide faces at the base body guarantee the desired grille size for the depth of layer. It is also within the scope of the invention to make the guide faces in the base body not continuous. In particular, this may be dispensed with in the base la of the base body.

In conclusion, the invention provides the advantage that almost all possible sizes for the depth of layer of the cells may be produced with one uniform base body, an inlet window and an outlet window. In addition, windows of the most different types of glass may be inserted in the base body. A considerable reduction of cells, which otherwise have to be kept available, also results therefrom. In particular, it is essential that a variable cell results.

Claims

1. Multi-purpose cell for photometric and/or spectrophotometric measuring, whose measuring chamber is formed by a base, two opposite side walls and two transverse walls which act as inlet and outlet windows and have parallel faces, wherein the base and the side walls form an elongate base body which is approximately Ushaped in cross-section and, on its inner sides, comprises numerous depressions or projections which follow one another at a defined spacing in the longitudinal direction, extend in the transverse direction and act as guide faces for optionally insertable inlet and outlet windows.

2. Multi-purpose cell as claimed in claim 1, wherein the guide faces are formed by grooves passing round in the transverse direction.

3. Multi-purpose cell as claimed in claim 1 or 2, wherein the base body and/or the inlet and outlet windows comprise a sealing device on their mutual contact faces.

4. Multi-purpose cell as claimed in claim 2, wherein the resilient sealing lips are arranged in the grooves.

5. Multi-purpose cell as claimed in claim 4, wherein the sealing lips in each case are only arranged in one side wall of a groove.

6. Multi-purpose cell as claimed in any one of the preceding claims, wherein the base body is formed in one piece.

7. Multi-purpose cell as claimed in one of the preceding claims, wherein the base body consists of plastics material resistant to acid and to lye solution.

8. Muiti-purpose cell as claimed in one of the preceding claims, wherein the cell is provided with additional infeed discharge, passage ducts or tempering ducts.

9. Multi-purpose cell as claimed in any one of claims 1 to 3, wherein the sealing device consists of plastics material strips which are C-shaped in cross section and embrace the edge of the inlet or outlet window on both sides.

10. A multi-purpose cell substantially as hereinbefore described with reference to the accompanying drawings.