GB2491850A

GB2491850A - A dilution system

Info

Publication number: GB2491850A
Application number: GB1109920.7A
Authority: GB
Inventors: Richard Graves
Original assignee: XOPTIX Ltd
Current assignee: XOPTIX Ltd
Priority date: 2011-06-14
Filing date: 2011-06-14
Publication date: 2012-12-19
Anticipated expiration: 2031-06-14
Also published as: GB2491850B; GB201109920D0

Abstract

A dilution system comprises a first manifold 1 for the supply of a diluents, a second manifold 25, a tube 5 extending from the first manifold 1, an inlet tube 7 for a sample to be diluted which merges with the tube 5 from the first manifold to form a combined tube 15 in which the sample is diluted with the diluents and means for connecting an outlet 23 of the combined tube 15 to the second manifold 25. The inlet tube 7 and the tube 5 may be connected by way of a Y-connector 9. The combined tube may be split into first 21and second branches 23 with at least one of the branches connecting to the second manifold. Preferably the cross-sectional area of each combined tube 15 may be twice the cross-sectional area of the first and second branches which extends from the manifold. Mixing means, such as baffles, may be provided in each combined tube.

Description

DILUTION SYSTEM

This invention relates to a dilution system and more particularly is concerned with a dilution system which is able to produce relatively high dilution ratios with relatively low use of diluent.

Dilution methods and apparatus are known forcontrolled and automated dilution of fluids, especially liquids, such as slurries, for example for use in quality control procedures. Such dilution is required, for example, to provide a small sample of the content of the fluid being diluted, to condition that sample forfurther analysis! For example, the sample may be analysed in a particle size analyser to assess the quality of particles in a slurry.

Typical dilution ratios for very small particulates (for example around 5 microns) are greater than 250 times, and sometimes greater than 1000 times. Once the sample has been analysed, it would usually cause too much dilution to be returned to the original fluid and therefore must be recycled in some way! However, recycling is undesirable and potentially expensive. Consequently, until the present time the volume of waste sample has been so great that the potential advantages of closed loop quality control have not been realised.

It is therefore an object of the present invention to provide a dilution system which overcomes, or at least ameliorates, the above-described disadvantages! According to the present invention there is provided a dilution system comprising: a first manifold for the supply of a diluent; a second manifold; a tube extending from the first manifold; an inlet tube for a sample to be diluted, the inlet tube merging with the tube from the first manifold to form a combined tube in which the sample is diluted with the diluent; and means connecting an outlet of the combined tube to the second manifold.

The combined tube may be split into first and second branches with at least one of the first and second branches being connected to the second manifold.

One or more further combined tubes may be provided in each case with one of the first and second branches being connected to the second manifold and the other of the first and second branches merging with a further tube extending from the first manifold to form a further combined tube in which the sample is further diluted with the diluent.

Where more than one split combined tube is provided, a branch of one of the split combined tubes may be selected to provided a sample which is diluted substantially by a predetermined ratio.

The combined cross-sectional area of the first and second branches may correspond substantially to the cross-sectional area of the or each combined tube. For example, the cross-sectional areas of the first and second branches may be substantially the same and may be substantially half the cross-sectional area of the or each combined tube.

Mixing means may be provided in the or each combined tube. The mixing means may comprise static mixing means, such as one or more baffles.

A predetermined number, such as eight or ten, of tubes may extend from the first manifold. Any such tubes which are not required to produce the predetermined dilution ratio may be blocked off.

The first and second manifolds may be substantially circular in cross-section and may be interconnected by a substantially cylindrical member. At least part of one of the manifolds may be releasabJy secured to the cyiindricai member to allow rotation relative thereto, for example in order to align outlet apertures in the first and second manifolds.

The branch providing the sample diluted by the predetermined ratio may be connected to an analysing device, such as a particle size analyser.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 is a diagrammatic illustration of one embodiment of a dilution system according to the present invention; Figure 2 shows part of the apparatus shown in Figure 1 in more detail; Figure 3 shows an embodiment of an upper manifold forming part of a dilution system according to the present invention; and Figure 4 shows an embodiment of a lower manifold forming part of a dilution system according to the present invention.

The dilution system shown in the figures comprises an array of tubes along which the fluid to be diluted and a diluent, such as water, flow, the tubes being interconnected in a mannerwhich results in progressive dilution of the fluid. The invention will be described in relation to liquids which will generally flow downwardly through an array of upright tubes. However, the system could alternatively be employed to dilute gases and in any event the tubes need not be upright.

As shown in the figures, an inlet manifold 1 is provided above the array of tubes for containing a supply of diluent, such as water, the manifold being provided with an inlet 3 for diluent. A plurality of tubes 5 extend downwardly from the manifold for the passage of diluent. As illustrated, there are eight tubes 5 which are spaced along the manifold, each tube having the same cross-sectional area.

A ninth tube 7 provides a flow of sample liquid to be diluted, the tube 7 having the same cross-sectional area and the same head of pressure as the tubes 5.

Consequently the flow rate of liquid through each of the tubes 5 and 7 will be substantially the same.

A first tube of the array of tubes 5 merges with the sample tube 7, by way of a Y-connector 9, the inclined arms 11, 13 of the Y-connector each having the same cross-sectional area as the tubes 5 and 7. Clearly, it is not essential that the connector should be in the form of a Y. Once the arms of the connector join, the cross-sectional area of a tail 15 of the connector is twice the cross-sectional area of the inclined arms 11, 13 and tubes 5, 7, as shown more clearly in Figure 2. Consequently, the liquid in the tail 15 of the first connector has half the concentration of the original sample. That is a dilution ratio of two. A mixing means 17 is provided in the tail of each connector 9, for example in the form of a baffle or other static mixing means, to ensure the sample and the diluent are well mixed.

Below the mixing means 17 there is an inverted V-connector 19, the inclined arms 21, 23 of which each have half the cross sectional area of the tail 15.

Again, it is not essential that the inverted connector is in the form of a V. One arm 23 of the inverted connector is connected to an outlet manifold 25 to return diluted sample to the original liquid or to convey the diluted sample to waste or recycling (not shown).

The other arm 21 of the inverted connector is connected to an inclined inlet arm of a further conventional V-connector, the further connector having a further arm which is connected to the manifold 1 by a tube 5. The inclined arms of the further connector also have the same cross-sectional area as the tubes 5, while the further connector also has a tail having twice the cross-sectional area of the arms and the tubes 5. Consequently, the further conventional V-connector is substantially identical to the first-mentioned V-connector and serves to reduce the concentration of the sample to half that in the inlet arm, thus resulting in a dilution ratio of 4 compared to the original sample. The further conventional V-con nector also has a mixing means to ensure the liquids are well mixed and is then connected to a further inverted V-connector, which is substantially identical to the first-mentioned inverted V-connector. One arm of the further inverted V-connector is connected to the outlet manifold 25, while the other arm is connected to a further Y-connector to continue the dilution procedure.

It should be noted that the cross-sectional area of the various components of the Y-connector 9 and the inverted Y-connector 19 can be varied. Not only can the relative cross-sectional areas of the arms 11, 13 and 21,23 be different, but the combined cross-sectional areas of the arms 11, 13 and/or 21, 23 can be different to the cross-sectional area of the tail 15. Differing cross-sectional areas can affect the dilution ratio.

As shown in Figure 1, there are eight connectors, each diluting the sample by a factor of two. Thus in the illustrated embodiment there is an overall dilution ratio compared with the original sample of 256:1. However, the amount of diluent used is only eight times the volume of the original sample.

One of the outlets of the final connector is connected to an analysing device 27, such as a particle size analyser, the outlet of which is connected to the outlet manifold 25. However, if a lower dilution ratio is required the analysing device can be connected to the output of a different one of the connectors. In this case, the un-used tubes 5 can be closed off to prevent waste of the diluent.

The dilution ratio can be increased by using a greater number of tubes 5, or by feeding the output of the Jast of the connectors of one array to the sampie input of a further array. Alternatively or additionally, flow control means (not shown) can be provided in the inlets to any of the tubes 5 or 7 or at any of the dividing flowpaths to further control the dilution ratio. As a further option, the cross-sectional areas of the arms 11, 13 could be different in order to provide differing flow rates into the connector through the different arms. In such a case, the cross-sectional area of the tail 15 is still the same as the combined cross-sectional area of the arms.

Figures 3 and 4 show, respectively, an upper manifold and a lower manifold for use with the system described in relation to Figures 1 and 2, the manifolds being of generally cylindrical configuration. However, the upper and lower manifolds could take other forms.

The upper manifold 100 shown in Figure 3 includes an inlet 101 for diluent, which leads to a diluent reservoir 103, and an inlet 105 for a sample fluid to be diluted and which passes through the reservoir 103. The reservoir 103 is provided with a plurality of outlets 107, each of which is formed with a connector 109 externally of the reservoir. The connectors 109 facilitate connection to an array such as that shown in Figures 1 and 2. Any air in the system can be bled out of the reservoir byway of an outlet 111.

The lower manifold 113 shown in Figure 4 is similar in construction to the upper manifold and includes an outlet 115 for the diluted sample to be analysed, the outlet 115 passing through a reservoir 117 which accumulates all the dilution ratios that are not required. The reservoir 117 is provided with a plurality of inlets 119 for the dilution ratios that are not required, the inlets being connected to the array by way of connectors 121, and with an outlet 122. The dilution ratios that are not required can be returned by way of the outlet 122 to the stream from which the sample was extracted or can be sent to waste or for recycling.

The upper and lower manifolds are interconnected by a cylindrical member 124 which extends around a peripheral region of the manifolds and surround the array.

The upper and lower manifolds of Figures 3 and 4 allow the dilution ratio to be changed. To this end the outer ends 126 of the manifolds are mounted to the cylindrical member 124 in a way which enables them to be released, rotated and secured in position once again. Inner regions 128 are secured to the cylindrical member 124 by way of threaded fasteners which are received in threaded bores 123 formed in the manifolds and pass through apertures 125 formed in the cylindrical member 124 so as to prevent rotation between the cylindrical member 124 and the inner regions of the manifold. One or both of the outer regions 126 of the manifolds can be released by removing threaded fasteners which extend through apertures 130 in the outer regions of the manifolds and into threaded recesses 132 in the inner regions of the manifolds and the inlet 105 and/or the outlet 115 can be unscrewed from the respective connector 109 or 121. In practice, however, it is onJy necessary to release one of the manifolds and the lower manifold is considered to be the most convenient. The outer region of the manifold can then be rotated until the inlet 101 and/or the outlet 115 is aligned with the appropriate connector 109 and/or 121 to give the required dilution ratio from the array. Any unused connections are ideally closed with blanking plugs (not shown) to ensure an minimum amount of diluent is used.

The manifolds are generally connected to a process to be sampled by way of manually-operated or automatic valves as part of a closed-loop industrial process employing the results of the analysis of the diluted sample as part of its controls. -11 -

Claims

CLAIMS1. A dilution system comprising: a first manifold for the supply of a diluent; a second manifold; a tube extending from the first manifold; an inlet tube for a sample to be diluted, the inlet tube merging with the tube from the first manifold to form a combined tube in which the sample is diluted with the diluent; and means connecting an outlet of the combined tube to the second manifold.
2. A dilution system as claimed in claim 1, wherein the combined tube is split into first and second branches with at least one of the first and second branches being connected to the second manifold.
3. A dilution system as claimed in claim 2, wherein one or more further combined tubes are provided in each case with one of the first and second branches being connected to the second manifold and the other of the first and second branches merging with a further tube extending from the first manifold to form a further combined tube in which the sample is further diluted with the d iluent.
4. A dilution system as claimed in claim 3, wherein, where more than one split combined tube is provided, a branch of one of the split combined tubes is selected to provided a sample which is diluted substantially by a predetermined ratio.
5. A dilution system as claimed in claim 2, 3 or 4, wherein the combined cross-sectional area of the first and second branches corresponds substantially to the cross-sectional area of the or each combined tube.
6. A dilution system as claimed in claim 5, wherein the cross-sectional areas of the first and second branches is substantially the same and is substantially half the cross-sectional area of the or each combined tube.
7. A dilution system as claimed in any preceding claim, wherein mixing means is provided in the or each combined tube.
8. A diiution system as ciaimed in cJaim 7, wherein the mixing means comprises static mixing means.
9. A dilution system as claimed in claim 8, wherein the mixing means comprises one or more baffles.
10. A dilution system as claimed in any preceding claim, wherein a predetermined number of tubes extend from the first manifold.
11. A dilution system as claimed in claim 10, wherein any such tubes which are not required to produce the predetermined dilution ratio are blocked off.
12. A dilution system as claimed in any preceding claim, wherein the first and second manifolds are substantially circular in cross-section and are interconnected by a substantially cylindrical member.
13. A dilution system as claimed in claim 12, wherein at least part of one of the manifolds is releasably secured to the cylindrical member to allow rotation relative thereto.
14. A dilution system as claimed in claim 13, wherein at least part of one of the manifolds is releasably secured to the cylindrical member to align outlet apertures in the first and second manifolds.
15. A dilution system as claimed in any preceding claim, wherein the branch providing the sample diluted by the predetermined ratio may be connected to an analysing device.
16 A dilution system as claimed in claim 15, wherein the analysing device comprises a particle size analyser. -14-
17. A dilution system substantially as herein before described with reference to, and as shown in, the accompanying drawings.