AU697318B2

AU697318B2 - Sampling bottle arrangement

Info

Publication number: AU697318B2
Application number: AU45308/96A
Authority: AU
Inventors: Bjorn Dybdahl
Original assignee: Petrotech AS
Current assignee: Petrotech AS
Priority date: 1995-01-16
Filing date: 1996-01-10
Publication date: 1998-10-01
Anticipated expiration: 2016-01-10
Also published as: NO950150L; WO1996022517A1; NO300397B1; GB2311606B; GB9712397D0; AU4530896A; NO950150D0; GB2311606A

Description

SAMPLING BOTTLE ARRANGEMENT

This invention relates to a device for sampling bottles for fluid samples, preferably of the kind comprising a tubular container body having an end piece at each end thereof, and containing an axially freely displaceable piston, wherein there, within a first (lower) end piece, exists a combined inlet/outlet for letting the fluid sample into the sampling bottle and out therefrom, respectively, said fluid sample may consist of a mixture of fluids, e.g. oil and water, and wherein there, within a second (upper) end piece, exists a second combined inlet/outlet for a drive fluid for the piston, especially glycol.

When a sample fluid is to be filled into a sampling bottle using prior art technique (some of the actual sample is later discharged to be analyzed in an adequate apparatus) , the axially freely displaceable piston is pressed against first end piece formed with first inlet/outlet. The piston is pressed to this starting position by means of a drive fluid, preferably glycol, pumped into the bottle from an external tank through second inlet/outlet in second end piece.

Both first and second inlet/oulet are provided with shutoff valves.

With the piston resting against first end piece, first shutoff valve is opened for letting in fluid pumped into the sampling bottle exhibiting a pressure exceeding the pressure - back pressure - prevailing in the glycol at the opposite end side of the piston. During the sample fluid's flow into the sampling bottle, the previously pumped in glycol is gradually let out through second combined inlet/outlet through a back pressure regulator. The glycol pressed out from the sampling bottle is carried into a measuring apparatus determining the position of the piston within the sampling bottle.

When about 80% of the volume of the bottle is filled with the fluid let thereinto, the sampling is stopped. Thereafter, further 10% of the glycol located behind the piston is pressed out, in order to avoid possible build-up of pressure within the sampling bottle during transport from the samling area to the laboratory.

At the pressure loss taking place when the above-mentioned 10% of glycol is pressed out, gas is normally formed in an oil sample.

Prior to transferring the sample fluid stored within the sampling bottle to analysis apparatus, the fluid must be brought back to the original condition thereof. In the laboratory, this takes place by returning 10% glycol, thereafter mixing the sample within the sampling bottle prior to discharging the sample, wholly or in part, for analysis purposes. Such a mixing is necessary in order to secure that the sample has the same consistence as originally.

For such mixing of the sample, it is known to use a ball located between first end piece and the piston. The ball is set into motion by allotting the bottle e.g. oscillating movements manually, thus causing the sample to be mixed.

The known technique disclosed in the foregoing appears e.g. from U.S. patent specification No. 4,409,850. A disadvantage when using such a ball is that it is difficult to mix the sample properly, simultaneously as the ball may cause damages on end pieces and piston.

The object of the present invention is to provide a mixing body causing a very good mixing of the fluid sample, and which cannot damage end pieces and piston.

The object is achieved by a device, the characteristic features thereof appearing from claim 1.

In accordance with the invention, the sampling bottle is provided with a cylindrical mixing body having a through- going, preferably conical bore. The diameter of the mixing body is smaller than the internal diameter of the sampling bottle, the mixing body thus being capable of displacing itself axially within the sampling bottle by force of gravity by turning the bottle.

When the sampling bottle is to be emptied, or a smaller sample is to be withdrawn therefrom, the shutoff valve at first end piece is opened, and the fluid sample will start to flow out. The sampling bottle is emptied by pumping glycol once more in behind the piston which, thus, will press piston and mixing body such a distance that they finally rest against the inner end face of first end piece.

When the sample fluid is conducted into the sampling bottle, it is very important that there does not exist any dead volume between first end piece's inner end face, the mixing body and the opposing end face of the piston, because such dead volume could give rise to an undesired pressure fall when the fluid sample is conducted into the bottle, and because said dead volume could form residence chambers for residues of previous samples, residues of solvents left subsequent to cleaning and the like.

Thus, upon arranging a mixing body to replace the known _* ball, provisions should be taken to secure that said dead volume ideally is eliminated or at least is reduced to the greatest possible extent.

According to the present invention, one has, therefore, aimed at providing a sampling bottle of the kind defined in the introduction, and equipped with a mixing means, wherein the avoidance of said dead volume's formation is properly taken into account.

The mixing body is constituted by a cylindrical body having a diameter which is only insignificantly smaller than the internal diameter of the sampling bottle. The mixing body is provided with a through-going bore adapted to receive a complementary, projecting portion of the opposing piston.

An examplary embodiment of the invention is further explained in the following and with reference to accompanying drawings, wherein:

Figure 1 shows an axial section through a sampling bottle having a cylindrical container body, end pieces screwed into the ends thereof, as well as a piston and a mixing body arranged therebetween, and wherein piston and mixing body both are pressed towards first end piece's inner end face;

Figure 2 shows a section corresponding to figure 1, but here piston and mixing body are moved away from first end piece;

Figure 3 shows a section corresponding to figures 1 and 2, but here the mixing body is partly separated from the piston;

Figure 4 shows a section corresponding to figures 1, 2 and 3, but here the bottle is turned 180°, the mixing body being further displaced in relation to the piston.

As the introductorily mentioned shutoff valves for inlet/ outlet for glycol and for sample fluid, respectively, within _* the sampling bottle do not have any direct connection to the present invention, the valves are deleted from the figures of the drawings.

In the drawings, reference numeral 1 denotes a sampling bottle constituted by a tubular container body 1' having a first end piece 2 and a second end piece 3. By means of threads, the end pieces 2 and 3 are screwed into the container body 1' .

First end piece 2 is provided with a through-going channel 4 assigned a valve, not shown, serving to let in/out sample fluid to be stored within the bottle at a high pressure, to be analyzed at a later point of time. The pressure within the bottle may be 100-1000 bar.

Second end piece 3 is provided with a through-going channel 5 assigned a valve, not shown, serving to let in/out glycol or another liquid to form a pressure behind a piston 6. The piston 6 is provided with a projecting conical portion 6' which can be received in a complementary bore 7' in a mixing body 7.

Prior to sample fluid being conducted into the sampling bottle 1 , piston 6 and mixing body 7 are pressed by glycol to rest against the inner end face 8 of the end piece 2. As the conical portion 6' on the piston 6 fills the bore 7' in the mixing body 7, dead volume is avoided.

When sample fluid is conducted into the container body 1' , the valve (not shown) screwed into the channel 4 of the end piece 2 and, then, the sample fluid will press the mixing body 7 and the piston 6 away from the end piece 2, confer figure 2. The valve (not shown) screwed into the channel 5 of the second end piece 3, is opened simultaneously, so that glycol is pressed out from the sampling bottle 1.

When the desired degree of filling has been achieved, the valves are closed, and the sampling bottle is brought to the actual laboratory where the content of the sampling bottle 1 is mixed prior to sample fluid being taken out for analysis.

During mixing, the piston will not be capable of being displaced, as it occupies a state of balance between sample fluid at one side and glycol at the other side thereof.

As the mixing body 7 is provided with a through-going bore 7 • , it will be able to move axially within the container body 1*, confer figure 3. Figure 4 shows the sampling bottle subsequently to being turned 180°, in order to effect that the mixing body 7 once more shall gravitate through the sample fluid.

The mixing body 7 may be provided with one or more through- going bores 7*, but preferably one conical bore. Such a conical bore 7' gives, due to the shaping thereof, rise to a change of speed in the sample fluid being pressed through the bore 7' , which has been found to involve a very good mixing of the sample fluid.

Claims

96/22517 PCIYNO96/00004C l a i m s

1. A device for a sampling bottle (1) for fluid samples, comprising a preferably cylindrical container body (1') which can be fluid-tightly closed at the ends by means of end pieces (2, 3) with valves, said sampling bottle (1) internally being provided with an axially displaceable piston (6) and a mixing body (7) , c h a r a c t e r i z e d i n that the mixing body (7) is constituted by a preferably cylindrical member having one or more through-going bores (7').

2. A device for a sampling bottle as set forth in claim 1, c h a r a c t e r i z e d i n that the mixing body (7) is provided with one or more conically shaped, through-going bores (7') .

3. A device for a sampling bottle as set forth in claim

1 or 2, c h a r a c t e r i z e d i n that the piston (6) is provided with one or more projecting portions (6¹) adapted to be received complementarily within one or more bores (7¹) in the mixing body (7).

4. A device for a sampling bottle as set forth in one or more of the preceding claims, c h a r a c t e r i z e d i n that the piston (6) is provided with one or more conically shaped, projecting portions (6*).

5. A device for a sampling bottle as set forth in one or more of the preceding claims, c h a r a c t e r i z e d i n that the projecting portion, possibly portions, (6') of the piston (6) is/are adapted to fill entirely out a complementary bore, possibly complementary bores, (7") in the mixing body (7) .