GB2090814A - Continuous sampling method and apparatus thereof - Google Patents
Continuous sampling method and apparatus thereof Download PDFInfo
- Publication number
- GB2090814A GB2090814A GB8200162A GB8200162A GB2090814A GB 2090814 A GB2090814 A GB 2090814A GB 8200162 A GB8200162 A GB 8200162A GB 8200162 A GB8200162 A GB 8200162A GB 2090814 A GB2090814 A GB 2090814A
- Authority
- GB
- United Kingdom
- Prior art keywords
- chamber
- fluid
- sectional area
- cross sectional
- withdrawal point
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/10—Devices for withdrawing samples in the liquid or fluent state
- G01N1/20—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials
- G01N1/2035—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials by deviating part of a fluid stream, e.g. by drawing-off or tapping
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
An apparatus for extracting samples of a fluid flowing through a main stream pipe line (1) comprising: a by-pass loop (2) in which is located a chamber (3), b. for sampling a portion of the fluid passing through the by-pass loop, c. Means (14) responsive to the main stream fluid velocity varies the internal cross sectional area of the chamber at the sample withdrawal point so as to maintain a constant fluid velocity through the chamber. The means for varying the internal cross sectional area of the chamber at the sample withdrawal point comprises a movable hollow probe, through which the sample is withdrawn, which is adapted to be positioned at points of varying cross sectional area along the axis of a chamber having an expanding profile, and which is controlled by means of a standard linear activating control device operated by pneumatic, hydraulic or electrical means responsive to changes in the main stream fluid velocity. <IMAGE>
Description
SPECIFICATION
Continuous sampling method and apparatus therefor
The present invention relates to an apparatus and a method for continuously extracting fluid samples from a main stream, for instance a mixture of oil and water in a pipe line.
In recent years the accurate measurement of the amount of water in crude oil has become of increasing importance, hence there has been a need to develop improved sampling methods. In a crude oil pipe line the flow of discontinuous phase water is rarely uniform with time, transient water slugs normally being present, and it is necessary to ensure that such transient water slugs do not cause the collected sample to be unrepresentative of the pipe line throughput. In one method of sampling part of the pipe line flow is continuously diverted through a by-pass loop, from which a sample is extracted after the fluid has been thoroughly mixed, the remainder of the fluid in the loop being returned to the pipe line.In such a sampling method the liquid is pumped through the bypass loop at the same fluid velocity as in the pipe line, but for the method to be valid it is necessary to ensure that the liquid flows past the sample extraction point in the by-pass loop at a constant velocity substantially equal to the velocity of extraction of the sample, regardless of changes in the velocity of the liquid in the main pipe line. Otherwise the effects of momentum on entrained particles of different density from the continuous phase oil will lead to unrepresentative sampling.
Accordingly, the present invention relates to an apparatus for extracting samples of a fluid flowing through a main stream pipe line, said apparatus comprising:
1. means for continuously diverting part of the fluid in the pipe line through a by-pass loop in which is located a chamber,
2. means for continuously withdrawing from the chamber at a sample withdrawal point for transmission to an automatic sampling device a portion of the fluid passing through the by-pass loop, and
3. means responsive to the main stream fluid velocity for varying the internal cross sectional area of the chamber at the sample withdrawal point so as to maintain a constant fluid velocity through the chamber at the sample withdrawal point.
The invention also relates to a method for extracting samples of a fluid flowing through a main stream pipe line which comprises continuously diverting part of the fluid in the pipe line through a by-pass loop in which is located a chamber, continuously withdrawing from the chamber at a sample withdrawal point a portion of the fluid passing through the by-pass loop and transmitting this portion to an automatic sampling device and varying the internal cross sectional area of the chamber at the sample withdrawal point in response to changes in the main stream fluid velocity so as to maintain a constant velocity through the chamber at the sample withdrawal point.
In the apparatus and method of the present invention the velocity of the liquid passing through the chamber at the sample withdrawal point is maintained constant by varying the internal cross sectional area of the chamber at that point in response to changes in the velocity of the fluid in the main pipe line. Thus when the main stream flow rate increases the chamber cross sectional area is increased proportionately to correct the tendency of the flow rate in the chamber to increase and to maintain this at a constant level. Likewise when the main stream flow rate decreases, the chamber cross sectional area is also decreased proportionately to maintain a constant flow rate through the chamber at the sample withdrawal point.
The means for varying the internal cross sectional area of the chamber at the sample withdrawal point may comprise for instance means for applying pressure externally to a chamber with flexible walls to create a venturilike profile within the chamber, which profile can be varied in response to changes in the main stream fluid velocity. In this case the sample withdrawal point in the chamber is suitably a tube axially positioned in the chamber with an inlet at the point of variable cross sectional area facing towards the flow of fluid and an outlet external to the chamber which can be connected to an automatic sampling device.
In a preferred embodiment of the invention the means for varying the internal cross sectional area of the chamber at the sample withdrawal point comprise a movable hollow probe, through which the sample is withdrawn, which can be positioned at points of varying cross sectional area along the axis of a chamber having an expanding profile. In this embodiment the chamber has rigid walls and a profile which expands uniformly in the direction of flow from the point of entry of the fluid to a maximum cross section. The probe has an inlet facing towards the flow of fluid in the expanding part of the chamber, and is suitably profiled to avoid undue disturbance of the flow patterns which could cause preferential flow of either oil or water into the inlet, and an outlet external to the chamber which can be connected to an automatic sampling device.The position of the probe in the chamber is controlled by means of a standard linear activating control device operated by pneumatic, hydraulic or electrical means responsive to changes in the main stream fluid velocity.
Fluid entering the chamber is thoroughly mixed by the turbulence created at the sud den expansion, and the expanding profile also causes a progressive decrease in the fluid velocity through the chamber. Movement of the probe in the chamber in response to signals from the control device maintains the sample withdrawal point i.e. the probe inlet in a region of constant fluid velocity.
Preferably the head of the probe has a tapered profile which matches the profile of the expanding portion of the chamber, and the inlet is an annulus located on the shoulders of the probe connected with a central axial tube in the probe.
The probe outlet is suitably connected to a conventional automatic sampling unit such as that described in our British Patent Specification No: 1 501 903. This specification describes an automatic sampling device which comprises a conduit formed as a loop having ends which are adapted to be in open communication with a liquid source, a gear pump capable of circulating liquid at a substantially constant rate through the loop, a sample outlet valve in the loop downstream from the pump and a back pressure valve adapted to control the flow passage through the sample outlet and responsive to the upstream line pressure.
The apparatus of the present invention is further described with reference to the accompanying drawings in which
Figure 1 represents a sectional view of a chamber and probe forming part of an apparatus according to the invention,
Figure 2 represents a view of the probe along section AA in Fig. 1, and
Figure 3 represents a schematic diagram of a method according to the invention.
Referring to the drawings, an apparatus for continuously extracting samples of a fluid flowing through a main stream pipe line 1 comprises a by-pass loop 2 in which is located a chamber 3 containing a movable hollow
probe 4 through which the sample may be withdrawn. The chamber 3 has rigid walls and a profile 5 which expands uniformly in the direction of flow from the inlet 6 to a maxi
mum cross section. The probe 4 has an
annular inlet 7 connected to an axial tube 8
and an outlet 9 external to the chamber connected to an extracting gear pump 10.
The probe 4 has a head 11 and shoulders 12 which are profiled to match the profile 5 of the chamber. The probe 4 is mounted on a
pneumatic cylinder 1 3 which causes it to
move axially within the chamber towards or away from the inlet 6 in response to changes
in the fluid velocity in the pipe line 1.
In operation the fluid velocity in the pipe - line 1 is measured by the device 14 and flow
metering unit 15, and signals from the meter
ing unit 1 5 are fed by a line 1 6 into the
controller 1 7. Part of the fluid in the pipe line
1 is diverted through the by-pass loop 2 and
chamber 3 by means of the pump 18, the bulk of the fluid returning to the pipe line through the chamber outlet 1 9. The rate of extraction by the pump 1 8 is governed by a motor 20 which in turn is controlled by the controller 17, so as to maintain the fluid velocity in by-pass loop 2 substantially the same as in pipe line 1. A sample of the fluid passing through the chamber 3 is continually extracted through the probe 4 by means of the extracting gear pump 10, and passed to an automatic sampling device (not shown).
The position of the probe 4 in the chamber is controlled by the pneumatic cylinder 1 3 into which signals are fed from the controller 1 7 indicating changes in the fluid velocity in the pipe line 1, so that the position of the annular inlet 7, which forms the sample withdrawal point, is maintained within the expanding portion of the chamber at a position of constant fluid velocity substantially equal to the velocity of extraction of the sample.
Claims (10)
1. An apparatus for extracting samples of a fluid flowing through a main stream pipe line, said apparatus comprising:
a. means for continuously diverting part of the fluid in the pipe line through a by-pass loop in which is located a chamber,
b. means for continuously withdrawing from the chamber at a sample withdrawal point for transmission to an automatic sampling device a portion of the fluid passing through the bypass loop, and
c. means responsive to the main stream fluid velocity for varying the internal cross sectional area of the chamber at the sample withdrawal point so as to the maintain a constant fluid velocity through the chamber at the sample withdrawal point.
2. An apparatus according to claim 1 wherein the means for varying the internal cross sectional area of the chamber at the sample withdrawal point comprises means for applying pressure externally to a chamber with flexible walls to create a venturi-like profile within the chamber, which profile is variable in response to changes in the main stream fluid velocity.
3. An apparatus according to claim 2 wherein the sample withdrawal point in the chamber is a tube axially positioned in the
chamber with an inlet at the point of variable
cross sectional area facing towards the flow of fluid and an outlet external to the chamber which is connnected to an automatic sampling device.
4. An apparatus according to claim 1 wherein the means for varying the internal
cross sectional area of the chamber at the
sample withdrawal point comprises a movable
hollow probe, through which the sample is withdrawn, which is adapted to be positioned
at points of varying cross sectional area along
the axis of a chamber having an expanding profile.
5. An apparatus according to claim 4 wherein the chamber has rigid walls and a profile which expands uniformly in the direction of flow from the point of entry of the fluid to a maximum cross section.
6. An apparatus according to claim 4 or 5 wherein the probe has an inlet facing towards the flow of fluid in the expanding part of the chamber, and is profiled to avoid undue disturbance of the flow patterns which cause preferential flow of any one component of the fluid into the inlet, and an outlet external to the chamber which is connected to an automatic sampling device.
7. Ari apparatus according to any on of the preceding claims 4 to 6 wherein the profile of the expanding portion of the chamber, and the inlet is an annulus located on the shoulders of the probe connected with a central axial tube in the probe.
8. An apparatus according to any one of the preceding claims 4 to 7 wherein the position of the probe in the chamber is controlled by means of a standard linear activating control device operated by pneumatic, hydraulic or electrical means responsive to changes in the main stream fluid velocity.
9. A method for extracting samples of a fluid flowing through a main stream pipe line which comprises continuously diverting part of the fluid in the pipeline through a by-pass loop in which is located a chamber, continuously withdrawing from the chamber at a sample withdrawal point a portion of the fluid passing through the by-pass loop and transmitting this portion to an automatic sampling device and varying the internal cross sectional area of the chamber at the sample withdrawal point in response to changes in the main stream fluid velocity so as to maintain a constant velocity through the chamber at the sample withdrawal point.
10. A method according to claim 9 wherein the velocity of the liquid passing through the chamber at the sample withdrawal point is maintained constant by varying the internal cross sectional area of the chamber at that point in response to changes in the velocity of the fluid in the main pipe line using an apparatus described in any one of the preceding claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8200162A GB2090814B (en) | 1981-01-09 | 1982-01-05 | Continuous sampling method and apparatus thereof |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8100637 | 1981-01-09 | ||
| GB8200162A GB2090814B (en) | 1981-01-09 | 1982-01-05 | Continuous sampling method and apparatus thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2090814A true GB2090814A (en) | 1982-07-21 |
| GB2090814B GB2090814B (en) | 1984-08-30 |
Family
ID=26278067
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8200162A Expired GB2090814B (en) | 1981-01-09 | 1982-01-05 | Continuous sampling method and apparatus thereof |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2090814B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0262327A2 (en) * | 1986-10-02 | 1988-04-06 | Munk GmbH | Method and apparatus for measuring polluting substances in waste water |
| EP0390700A1 (en) * | 1989-03-31 | 1990-10-03 | Societe Du Pipeline Sud-Europeen | Device for the regulation of a liquid sampler |
| WO2002035208A1 (en) * | 2000-10-26 | 2002-05-02 | Outokumpu Oyj | Method and device for taking slurry samples from a process flow |
| US20100170350A1 (en) * | 2009-01-05 | 2010-07-08 | Jed Stevens | System for collecting a fluid sample |
| US7921739B2 (en) | 2002-12-20 | 2011-04-12 | Fjerdingstad Soelve J | In situ sampling and monitoring a fluid |
| US8322199B2 (en) | 2002-05-21 | 2012-12-04 | The Administrators Of The Tulane Educational Fund | Automatic sampling and dilution apparatus for use in a polymer analysis system |
-
1982
- 1982-01-05 GB GB8200162A patent/GB2090814B/en not_active Expired
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0262327A2 (en) * | 1986-10-02 | 1988-04-06 | Munk GmbH | Method and apparatus for measuring polluting substances in waste water |
| EP0262327A3 (en) * | 1986-10-02 | 1988-10-05 | Munk GmbH | Method and apparatus for measuring polluting substances in waste water |
| EP0390700A1 (en) * | 1989-03-31 | 1990-10-03 | Societe Du Pipeline Sud-Europeen | Device for the regulation of a liquid sampler |
| FR2645271A1 (en) * | 1989-03-31 | 1990-10-05 | Pipeline Sud Europ | LIQUID PROD UIT SAMPLER ADJUSTMENT DEVICE |
| WO2002035208A1 (en) * | 2000-10-26 | 2002-05-02 | Outokumpu Oyj | Method and device for taking slurry samples from a process flow |
| AU2002210608B2 (en) * | 2000-10-26 | 2006-09-28 | Outotec Oyj | Method and device for taking slurry samples from a process flow |
| CN100401037C (en) * | 2000-10-26 | 2008-07-09 | 奥托库姆普联合股份公司 | Method and device for taking slurry samples from a process flow |
| US8322199B2 (en) | 2002-05-21 | 2012-12-04 | The Administrators Of The Tulane Educational Fund | Automatic sampling and dilution apparatus for use in a polymer analysis system |
| US7921739B2 (en) | 2002-12-20 | 2011-04-12 | Fjerdingstad Soelve J | In situ sampling and monitoring a fluid |
| US20100170350A1 (en) * | 2009-01-05 | 2010-07-08 | Jed Stevens | System for collecting a fluid sample |
| US8342043B2 (en) * | 2009-01-05 | 2013-01-01 | Velcon Filters, Llc | System for collecting a fluid sample |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2090814B (en) | 1984-08-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4307620A (en) | Liquid sampling system | |
| US6128962A (en) | Three-phase fluid flow measurement system and method | |
| US5390547A (en) | Multiphase flow separation and measurement system | |
| US4037475A (en) | Sampling device | |
| US2322018A (en) | Sampling and metering device | |
| US4149403A (en) | Determining steam quality | |
| US3765226A (en) | Self-powered sample probe | |
| CN110987097B (en) | Method for measuring gas-liquid multiphase flow by using pressure fluctuation | |
| US3924448A (en) | Pressure drop polymer concentration meter (pcm) | |
| GB2090814A (en) | Continuous sampling method and apparatus thereof | |
| Gill et al. | Data on the upwards annular flow of air-water mixtures | |
| Osman et al. | Experimental analysis of high-speed air–water jet flow in an abrasive water jet mixing tube | |
| GB1523619A (en) | Method and apparatus for liquid sample analysis | |
| KR950702703A (en) | Measuring fluid flow rate | |
| US4049381A (en) | Apparatus and method of fluid sample analysis | |
| US5092159A (en) | Method and apparatus utilizing a single nozzle for effecting measurment of steam characteristics | |
| GB2030963A (en) | Liquid Sampling System | |
| Scott et al. | Transport of solids by gas‐liquid mixtures in horizontal pipes | |
| US3377867A (en) | Automatic sampler | |
| US4530233A (en) | Method and apparatus for distinguishing between different gas or gas mixtures using a flow tube | |
| Wilkens et al. | Studies of multiphase flow in high pressure horizontal and+ 5 degree inclined pipelines | |
| CA1078215A (en) | Fluid sample dilution for chromatographic analysis | |
| GB2128756A (en) | Flow measurement of multi- phase fluids | |
| Moujaes | Measurement of slurry concentration and flow rates in shell and tube slurry heat exchangers | |
| RU2155949C2 (en) | Method and device to take representative sample of flow of polyphase medium |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |