GB2028164A

GB2028164A - Device for introducing samples into analyzer of apparatus for granulometric analysis of particles contained in fluids

Info

Publication number: GB2028164A
Application number: GB7834157A
Authority: GB
Original assignee: Jushunev M N
Current assignee: Jushunev M N
Priority date: 1978-08-22
Filing date: 1978-08-22
Publication date: 1980-03-05
Also published as: GB2028164B

Abstract

A device for feeding a liquid sample into apparatus for granulometric analysis of the particles in the liquid comprises a downwardly tapering funnel 1 opening at its lower end into channel having a horizontal flow cross-section 5 followed by a vertical flow section 6. The horizontal flow section has a length 3-5 times its diameter and the vertical flow section has a diameter which, in its upper zone, progressively increases from an initial value to between 4-6 times that value then progressively diminishes back to its initial value. The horizontal section hold particles which precipitate out of a sample during a settling time when bubbles escape prior to analysis. The vertical section produces eddies which break- up clumps of coalesced particles from the horizontal section and distributes these uniformly in the liquid while analysis is being carried out. <IMAGE>

Description

SPECIFICATION Device for introducing samples into analyzer of apparatus for granulometric analysis of particles contained in fluids The present invention relates to a device for introducing samples into an analyzer of an apparatus for granulometric analysis of particles contained in fluids. The invention is readily applicable to the analysis of suspensions of low concentrations. It is applicable, for example, to systems for the analysis of particles of impurities contained in fuels and oils.

In accordance with the present invention there is provided a device for introducing a liquid sample into an apparatus for the granulometric analysis of particles contained in the liquid, the device comprising a downwardly tapering funnel communicating at its lower end with a channel having an upper horizontal flow section whose length is approximately 3 to 5 times its diameter and from which liquid is guided into a vertical flow section whose cross-section progressively increases in its upper zone from an initial value to between substantially 1 6 to 36 times the initial value and then progressively diminishes back to its initial value in a lower zone of the vertical flow portion.

Preferably the channel is transparent and conveniently both the channel and the funnel have circular cross-sections. Obviously, if the horizontal flow section is other than circular, the ratio of its diameter to its length could lie slightly outside the range 3 to 5 and it is for this reason that the range of the length of the horizontal section to its diameter can only be given approximately. It is to be understood that if the cross-section is other than circular, the diameter is to be understood as being that of a notional circle giving the same area as the cross-section.

The device of the invention enables an improved accuracy of analyzing particles contained in individual samples of fluids to be obtained. The presence of the horizontal section of the channel which communicates with the funnel makes it possible for a sample to settle during a period of time sufficiently long to remove air bubbles from the sample. Particles of impurities, which precipitate during this time, are kept in the horizontal section of the channel and then wash away with the liquid flowing into the expanded vertical section of the channel where break-up of coalesced particles and their subsequent thorough mixing with the liquid occurs. The analyzer therefore receives liquid which is free of air bubbles and coalesced particles and is more accurate in consequence.

The invention will now be described in more detail, by way of example, with reference to the accompanying drawing which is a schematic diagram of a device for introducing samples into an analyzer of an apparatus for granulometric analysis of particles contained in fluids.

The device shown in the single figure 1 comprises a vertical cone funnel 1 having a bottom outlet connected to a channel 2 of changing shape and cross-section which communicates at its lower end with a supply channel of an analyzer 3 of equipment 4 for granulometric analysis of particles contained in liquid entering it. Immediately downstream of the funnel 1, a shaped first portion of the channel 2 has a horizontal flow section 5 of a length roughly equal to 3 to 5 times the diameter dof the channel 2 at this point.

Downstream of the portion, the channel 2 has a vertical flow section 6 of a diameter which gradually increases in a zone 7 until it is 4 to 6 times greater than its initial value, and then gradually reduces in a zone 8 to its initial value. The equipment 4 is provided with a digital display unit 9 indicating the amount and sizes of particles of impurities detected in fluids subjected to analysis.

It is expedient that the funnel 1 and the horizontal section 5 of the channel 2 should be transparent to enable the analyst to observe the disappearance of bubbles, as well as the precipitation and subsequent washing away of particles. The funnel 1 carries an upper mark 11 and lower mark 10 indicating the volumes of samples.

The device operates as follows: Prior to analyzing a sample of a fluid, the analyzer 3, channel 2 and funnel 1 are filled with a thoroughly purified fluid having a composition and properties similar to those of the fluid subjected to analysis. In the funnel 1, the fluid level must be as high as the mark 10. The fluid filling the analyzer 3, channel 2 and funnel 1 must be devoid of particles with sizes greater than the sensitivity threshold of the analyzer 3, This fluid must also be bubblefree.

A sample to be analyzed is poured into the funnel to fill it to the level of the mark 11 and is then allowed to settle to eliminate air bubbles produced by the pouring or sampling.

The setting time is dependent upon the viscosity and density of the fluid and the height of the fluid column. For example, a sample of 100cm3 of machine oil takes 1 to 2 minutes to settle.

The settling is accompanied by ascent of air bubbles and precipitation of particles of impurities suspended in the fluid. The larger and heavier particles accumulate in the horizontal section 5 of the channel 2. When the fluid being analyzed is allowed to flow after the settling time, these particles are washed down by the flow. To facilitate the washing downwards of such particles, the section 5 is of a small diameter such as 3 to 4mm. As the fluid being analyzed starts to flow, the appara tus 4 is brought into operation. As particles of impurities carried by the flow of fluid being analyzed reach the analyzer 3, the latter produces electric signals transmitted to the display 9.

Fluid is supplied from the funnel 1 via the channel 2 to the analyzer 3 by gravity; pure compressed air may also be used for the purpose, especially in the case of highly viscous fluids, to ascert pressure on the top of the fluid.

All particles accumulated in the section 5 of the channel 2 tend to wash away simultaneously, with the result that some of these particles coalesce or cling together temporarily forming unstable aggregates. From the upper U-shaped portion of the channel 2, such aggregates proceed to the vertical flow section 6 which gradually expands in cross-section in the zone 7 and gradually contracts again in the zone 8. The zones 7 and 8 are mirror inages and the diameter of the zone 7 increases from an initial diameter of 3 to 4mm to a diameter of substantially 4 to 6 times that amount. Upon reaching the zone 7, such aggregates disintegrate because of the eddying which occurs there, and consequently the particles are uniformly distributed over the cross-sectional flow of fluid being analyzed.

As a result, the data obtained by the apparatus 4 is reliable as it is unaffected by coalesced particles.

All parts of the device through which the liquid flows are of circular cross-section.

Claims

1. A device for introducing a liquid sample into an apparatus for the granulometric analysis of particles contained in the liquid, the device comprising a downwardly tapering funnel communicating at its lower end with a channel having an upper horizontal flow section whose length is approximately 3 to 5 times its diameter and from which liquid is guided into a vertical flow section whose cross-section progressively increases in its upper zone from an initial value to between substantially 1 6 to 36 times the initial value and then progressively diminishes back to its initial value in a lower zone of the vertical flow portion.

2. A device as claimed in Claim 1, in which the channel is transparent.

3. A device as claimed in Claim 1, in which the funnel and the channel have a circular cross-section.

4. A device as claimed in Claim 1, Claim 2 or Claim 3, in which the funnel has two vertically spaced liquid level markers.

5. A device as claimed in Claim 1, arranged and adapted to operate substantially as described with reference to the accompanying drawing.

6. A method of using the device claimed in Claim 1, in which a calibration run is performed by running through the apparatus a clean sample of the liquid before the sample liquid is run through the apparatus.

7. A method of using the device claimed in Claim 4, in which the funnel is filled with a clean liquid up to the level of the lower of the two markers and a volume of the liquid sample to be analyzed is then introduced to raise the level of the liquid in the funnel to the upper liquid level marker before analysis is commenced.