WO2001055694A1

WO2001055694A1 - Method and device for reflecting, in a sampling container, the environment of a pressurized fluid system, and such sampling container

Info

Publication number: WO2001055694A1
Application number: PCT/NO2001/000028
Authority: WO
Inventors: Sølve FJERDINGSTAD
Original assignee: Fjerdingstad Soelve
Priority date: 2000-01-26
Filing date: 2001-01-25
Publication date: 2001-08-02
Also published as: NO20000400L; NO20000400D0; NO311383B1; AU2892501A

Abstract

In order to reflect, in a sampling container, the environment within a pressurized fluid system, pressurized fluid tapped from the pressurized fluid system is caused to flow through the sampling container (22) and back into the fluid system for a predeterminedtime interval. When flowing through the sampling container thepressurized fluid sweeps one or more substrate bodies (60; 64, 65; 75; 78) having representative material surfaces of a configu-ration and nature adapted to simulate the environment of the fluid system.

Description

METHOD AND DEVICE FOR REFLECTING, IN A SAMPLING CONTAINER, THE ENVIRONMENT OF A PRESSURIZED FLUID SYSTEM, AND SUCH SAMPLING

CONTAINER

The invention relates to a method and device for reflecting, in a sampling container, the environment of a pressurized fluid system, and to such sampling container.

The applicant^'s own EP patent No. 0 548 187 B1 , the disclosure of which is incorporated herein by reference, describes a method and a sampler for taking a representative fluid sample from a pressurized fluid system. The sampler comprises a pressure chamber adapted to removably receive a sampling container. An inlet of the sampler pressure chamber is connected to a bleed point of the pressurized fluid system of which the fluid is to be controlled, and the fluid in the system is caused to flow for a predetermined time interval through the sampling container in the pressure chamber, the outlet of the sampler normally being connected to a return point of the fluid system, whereupon the sampler is disconnected from the fluid system, the pressure in the pressure chamber is relieved and the sampling container, now containing a representative sample of the fluid in the system, can be removed from the sampler for analysing its contents. The patent is particularly concerned with particle purity control of fluid samples from pressurized fluid systems such as hydraulic and central lubricating systems that previously did not easily permit sampling of representative samples to be tested for purity with respect to particle contamination. The patented technology eliminates the risk that the sampling operation itself could cause contamination of the sample, and permits use of low-cost standard glass or plastic bottles as sample containers, even when the fluid present in the fluid system operates under high pressures.

The technique according to the above patent has proved to be well suited also for sampling with the aim to study micro-organisms, such as bacteria living in flowing pressurized fluids, such as lubricating oil, water or other fluids in which such micro-organisms are undesirable. The particular advantage achieved over the prior art by using the above patented technique for sampling micro-organism- containing fluids, is that the sampler permits isolating the micro-organisms in a pressurized condition followed by controlled decompression of the fluid contained in the sampler, in a manner preventing bursting of the cells of the microorganisms. However, since some micro-organisms often tend to stick to material surfaces of a piping system, it is not always easy to reflect the environment of the sample in a manner permitting analysis of micro-organisms or bio-film growth without having to transfer the entire fluid environment to the laboratory. Even if a significant bacteria population is present in a sample, it may not easily be caused to grow in an ordinary laboratory sample test. Further, bio-film deposited on a surface could be a subsrate for micro-organisms to settle on, preventing them from leaving the fluid system on a sampling operation. Removing such bio-films from pipe systems has proved to be difficult and in some cases the entire piping system has to be demolished and replaced by a new one, at very high costs. Thus, from technical as well as economical grounds there is a long felt need within the industrial and also the medical fields, for a simple method and apparatus permitting analysis of the environment of fluid systems of the above mentioned kind, with the aim to improve the possibility of precluding bacterial growth and bio-film formation in such fluid systems. This need is met by a method, device and sampling container as defined in the appending claims.

By placing substrate bodies having suitable material surfaces in sampling containers of the type described in the above EP patent No. 0 548 187, in which bio-film is allowed to grow freely on the material surfaces during and after flowing of the pressurized fluid of interest through the sampler, and transferring such sampling containers provided with such substrate bodies to e.g. a laboratory for analysis, the accuracy of determining the form of bacteria, growth conditions and rate of bio-film formation, if any, is greatly enhanced. Thus, e.g. bacteria present in the pressurized fluid are permitted to settle on representative substrate sur- faces reflecting materials and other conditions representative of the system, including backwaters and flow rates to be reflected in a manner to provide the best possible similarity to the conditions prevailing in the pressurized fluid system of interest. This allows of an early observation of possible growth of micro- organisms, bio-film etc, permitting precautions to be taken such that the extent of damage due to such conditions can be significantly less than if such growth had been discovered only at a later time.

Admittedly, flowing fluid over material surfaces with the aim of observing the occurrence and possible growth of micro-organisms is well known, but not in connection with a sampling container to be used in a sampler of the type disclosed in EP-patent No. 0 548 187, resulting in the significant advantages described above.

While the invention is primarily intended for use in connection with prob- lems caused by bacteria or other micro-organisms that may be present in pressurized fluid system, it is also well suited for studying other environments or conditions that may cause problems in pressurized fluid systems, such as corrosion, for example.

The invention is described below with reference to the drawings in which: Fig. 1 is a longitudinal section through a sampling container provided with a first embodiment of the device according to the invention;

Fig. 2 shows a detail of the device shown in fig. 1 ;

Fig. 3 is a longitudinal section through a sampling container provided with a second embodiment of the device according to the invention; Fig. 4 shows a detail of the latter device; and

Figs. 5 and 6 are further examples of possible embodiments of the device according to the invention.

As noted above, the present invention is primarily intended to be used in connection with the invention according to EP patent 0 548 187, and therefore it is referred to that patent for a comprehensive understanding of the sampling process and equipment, which, apart from the sampling container with accessories, will not be described in detail here.

Shown in fig. 1 is a sampling container 22 in the form of a glass bottle provided with a removable cap 24, generally similar to the sampling container 22 and cap 24 according to the above EP patent. Cap 24 is provided with a lateral entrance 32 followed by a dependent central tube 34 and exit 35, substantially similar to the entrance 32, tube 34 and exit 35 described in the above patent. According to the present invention, internally of the sampling bottle 22 there is a device, generally denoted by reference numeral 50, adapted to reflect or imitate the surroundings or environment prevailing in a pressurised fluid system (not shown). Pressurised fluid from the fluid system is caused to flow into the sampling bottle 22 via entrance 32, tube 34 and discharge from the sampling bottle through exit 35 as indicated by arrows in fig. 1 , and as described in more detail in EP patent 0 548 187.

A first embodiment of the device according to the invention is shown in fig. 1 and 2. It comprises a frame 52 consisting of a pair of diametrically opposite re- tainer pins 54 which, by means of, e.g. pin head 51 and bottom threads 53, are removably secured to upper and lower support rings 55, 56 adapted to engage the inside top surface of cap 24 and inside bottom surface of sampling bottle 22 , respectively, coaxially of the central tube 34, and preferably an intermediate bracing ring 58. Frame 52 carries a plurality, twelve in the example shown, substrate bod- ies which, in this example, are in the form of annular disks 60 which are removably arranged on the support pins 54 through diametrically opposite guide holes 62, six disks on either side of bracing ring 58, spaced by spacers 57.

The device 50 according to the invention, consisting of frame 52 with substrate bodies 60 and intermediary and overlaying spacers 57 inserted on retainer pins 54 constrained between top and bottom support rings 55, 56, constitutes an independent, self-contained assembly or "pack" which, when inserted, is retained in position in sampling bottle 22 by cap 24 pressing against the upper surface of top ring 55 when the cap, such as by means of threads 59, is secured to sampling bottle 22. Advantageously the lower support ring 56 in frame 52 may have a con- cave lower surface engaging a correspondingly convex inside bottom surface of sampling bottle 22 to retain frame 52 centrally positioned in bottle 22.

While in the example shown the annular substrate disks 60 are frusto- conical in cross-section and the disks 60 below bracing ring 58 are inverted relative to the disks 60 above it, the disks could of course all face in the same direc- tion, or they could be flat, i.e. not conical, if desired.

When using the device according to the invention as illustrated in figures 1 and 2 and with special reference to the above EP 0 548 187, the sampling bottle 22 containing the substrate pack consisting of frame 52 and substrate disks 60 is placed in the pressurized sampling chamber 2 of a sampler 1 as described in the EP patent, and the inlet valve 18 of the sampler 1 is opened to permit pressurised fluid from the pressurised fluid system to be tested to flow into the sampling bottle 22 through entrance 32 and tube 34, and out of the bottle through exit passage 35. When flowing through bottle 22, the pressurised fluid will pass between and sweep the various substrate disks as indicated with arrow, just like the fluid sweeping the corresponding material substrate surfaces in the pressurised fluid system to be sampled and tested. Upon termination of the sampling period, say two weeks, the outlet valve of the pressure chamber is closed and the pressure chamber gradually decompressed consistent with a predetermined routine, whereupon the sampling bottle is sent to a laboratory or the like to have its contents analysed. The analysis would generally consist in determining possible occurrence and form of microbes, and possible organic deposits on the disk surfaces. Alternatively the substrate bodies could be subjected to additional labora- tory growth tests or sent directly to microscopy.

Figs. 3 and 4 illustrate another example of an embodiment of the device according to the invention. In this embodiment the substrate bodies are in the form of pairs of substantially rectangular plates 64, 65 extending longitudinally in a spaced relationship in bottle 22, preferably symmetrically on either side of central tube 34. The radially innermost plate 65 of each pair is removably attached at its lower end to a bottom support ring 70 such as by fasteners 68, while the radially outermost plate 64, through upper holes 71 , are hooked onto pins 73 secured to an upper support ring 69. The bottom end portion of the outermost plates 64 is hooked via lower holes 71^' and spacers 72 onto pins 73^' attached to the inner- most plates 65. The pairs of substrate plates 64, 65 serve to form a labyrinth-like flow pattern for the through-flowing pressurised fluid, promoting contact of the fluid with the substrate surfaces . In addition , a "backwater" could be created as indicated with arrow 74, mimicking corresponding backwaters in the fluid system to be sampled. As an alternative, the outer and inner rectangular plates 64, 65 could be replaced by an outer and inner hollow cylinder (not shown) coaxially arranged around the entrance tube 34.

Fig. 5 illustrates a further example of a cylindrical substrate body, such as a single steel cylinder 75 having perforations 76 through which the fluid is allowed to circulate to permit deposition of organic materials, if any, at the surfaces of cylinder 75.

Fig. 6 illustrates another possible embodiment of substrate bodies of the device according to the invention, here in the form of a set of flat rings78 stacked coaxially with tube 34 in the sampling bottle, permitting testing of the fluid with respect to crack corrosion.

In all of the embodiments of the device according to the invention as described and illustrated in the drawings, the substrate bodies 60; 64, 65; 75; 78 are easily removable, one by one, from their respective retaining means for being ana- lysed. They would normally consist of the same material as that contacting the pressurised fluid in the fluid system to which the sampling bottle is connected, e.g. pipes made of cast iron or steel in the case of hydraulic or lubricating systems, copper tubes in water systems, while electro-polished stainless steel may be appropriate in medical systems. Alternatively the substrate bodies may substantially consist of a lower cost support material such as plastic, covered by a surface layer made of the substrate material to be tested.

From a study of the above disclosed examples of embodiments of the present invention, those skilled in the art will readily appreciate that the configuration and nature of the substrate bodies may be varied in almost innumerable ways, to provide an effective simulation of the environment of a pressurized fluid system of interest. The substrate bodies may of course be assembled and retained in other ways than disclosed here. What is important is that the various substrate bodies are easily removable from their retaining means, ready for being analysed or for being used separately in further growth tests The sampling container 22 itself, including cap 24, is not limited to the shapes illustrated in the drawings; it could have any shape and consist of any material adapted to a device according to the invention which in its turn is specifically adapted to the fluid and/or fluid system to be tested. .

Claims

PA TENT CLAIMS:

1. A method for reflecting, in a sampling container, the environment of a pressurized fluid system, where pressurized fluid from the fluid system is caused to flow through the sampling container (22) and back to the fluid system during a predetermined time interval, characterized by causing fluid flowing through the sampling container to sweep one or more substrate bodies (60; 64, 65; 75; 78) having representative material substrate surfaces of a configuration and nature adapted to simulate the environment of said pressurized fluid system.

2. A device for reflecting, in a sampling container, the environment of a pressurized fluid system, said sampling container (22) adapted to receive pressurized fluid from the pressurized fluid system that is flowed through the sampling container and back into the fluid system for a predetermined time interval, characterized in that it comprises a removable assembly adapted to be placed in the sampling container (22) and including one or more substrate bodies (60; 64, 65; 75; 78) having representative material substrate surfaces of a configuration and nature adapted to simulate the environment of the fluid system.

3. A device according to claim 2, characterized in that the substrate bodies are in the form of a plurality of flat or conical, annular disks (60) arranged in a coaxial, spaced manner.

4. A device according to claim 2, characterized in that the substrate bodies are in the form of one or more pairs of opposed spaced rectangular plates

(64, 65).

5. A device according to claim 2, characterized in that the substrate bodies are in the form of two or more coaxially spaced hollow cylinders.

6. A device according to claim 2, characterized in that the substrate bodies are in the form of a perforated single hollow cylinder (75).

7. A device according to claim 2, characterized in that the substrate bodies are in the form of flat rings stacked upon each other.

8. A sampling container to be used in a sampler for sampling a representative fluid sample from a pressurized fluid system, characterized in that it contains one or more substrate bodies (60; 64, 65; 75; 78) having representative material substrate surfaces of a configuration and nature adapted to simulate the environment of the fluid system.