WO2011017734A1

WO2011017734A1 - Fluid sampler

Info

Publication number: WO2011017734A1
Application number: PCT/AU2010/000916
Authority: WO
Inventors: Tim Warren; Paulo De Souza; Hartmann Klaas; Karl Abetz
Original assignee: Commonwealth Scientific And Industrial Research Organisation
Priority date: 2009-08-10
Filing date: 2010-07-19
Publication date: 2011-02-17
Also published as: AU2010282197A1; WO2011017734A8

Abstract

This invention concerns a fluid sampler, in particular of the immersible type. The apparatus comprises a rack, along the length of which are stations for securing respective self-contained sample vessels. A mechanism is arranged along the rack for selectively and sequentially collecting a sample at each station. Typically, a sample collecting vessel is mounted at each station, and the mechanism operates to close each sample vessel along the rack. In another aspect the invention is a robotic platform equipped with the fluid sampler.

Description

Title

Fluid Sampler

Technical Field

This invention concerns a fluid sampler, in particular of the immersible type. In another aspect the invention is a robotic platform equipped with the fluid sampler.

Background Art

Existing techniques used to acquire samples of seawater involve immersing an open ended tube, such as a Niskin bottle, to the required depth and then manually triggering spring-loaded caps at both ends of the tube, to close the tube and capture the sample. The tube is typically let down into the sea at the end of a line and, when the required depth is reached, a weight is dropped down the line to trigger closure. The closed tube can then be drawn back up and the seawater sample transferred to a flask for analysis.

Automated sample collection devices involve the use of complex and expensive valve and syringe systems. There is a large divide between the available cost effective Niskin bottles, and the complex automated samplers that are on the market.

Disclosure of the Invention

In a first aspect the invention is an immersible apparatus for collecting fluid samples, comprising a rack, along the length of which are stations for securing respective self- contained sample vessels, and a mechanism arranged along the rack for selectively and sequentially collecting a sample at each station.

Typically a sample collecting vessel is mounted at each station, and the mechanism operates to close each sample vessel along the rack.

The apparatus may be made suitable to collect samples of any fluid, for instance by ensuring appropriate materials are used in its fabrication. Very simple inexpensive materials would be sufficient to collect any low or moderate temperature fluid, including air, water and water solutions. Corrosive fluids would require more careful selection of the materials, and so would other exotic requirements such as collecting samples in outer space or at great ocean depths. It is important that the materials chosen for the sample vessels will not contaminate the fluid being collected.

A linear arrangement of the apparatus would make the design amenable to modularization. This in turn could allow customisation of each instantiation, with a predetermined number of stations for sample vessels, according to the task at hand.

The apparatus may easily be associated with any sensors that provide a signal for activating closure of the sample vessels. Any sensors could be used, but in the marine environment temperature, salinity, pH, turbidity and dissolved oxygen (DO) sensors would obviously be useful. The apparatus may be arranged to be autonomously triggered given the fulfilment of any set of desired environmental criteria identified by an array of sensors. Such apparatus might be relatively simple to manufacture, have few moving parts, and be easy to assemble, modify and maintain. The apparatus may easily be miniaturized with a vessel size suitable, say, to collect samples of 50-10OmL. A low unit cost presents the opportunity to conduct large scale surveys by deploying many units at once. A small overall size, also permits use of the sampler on a wide range of small autonomous or manual robotic vehicles, and in cramped environments.

A water sampler employing the invention is readily deployed on autonomous underwater vehicles (AUVs), and remotely operated underwater vehicles (ROVs), as well as fixed underwater stations. In such applications it is expected that location (latitude, longitude and depth) and environmental sensors, would be used to activate closure of the sample vessels.

In a second aspect the invention is a robotic platform, such as an Autonomous Underwater Vehicle (AUV) or a Remotely Operated Vehicles (ROV), fitted with the apparatus for collecting fluid samples as described above, wherein closure of the fluid collecting vessels takes place under control from the platform.

Brief Description of the Drawings An example of the invention will now be described with reference to the accompanying drawings, in which: Fig. 1 is a pictorial view of a fluid sampler with all the sample vessels open. Fig. 2(a) is a pictorial view of a fluid sampler subassembly comprising three segments.

Fig. 2(b) is a pictorial view of a fluid sampler subassembly comprising three segments and two sample vessels.

Fig. 3 is a pictorial view of a fluid sampler with two of the sample vessels closed.

Fig. 4 is a block diagram of a control arrangement for a fluid sampler mounted on a robotic platform.

Best Modes of the Invention

Referring first to Fig. 1, the sampler 10 is made up with three tiers of racking, that is an upper tier 21, a middle tier 22 and a lower tier 23. Each tier in turn is made up of a selected number of modular rack segments, one of which is indicated at 30. In this case there are three segments in each tier. The number of segments 30 used in each tier defines the number of vessels that can be accommodated and the length of the sampler 10. The sampler can be put together with any selected number of rack segments in each tier.

As seen in more detail in Fig. 2, each rack segment 30 is made up of two halves 31 and 32 that fit together to hold one or more sample vessels 40 in respective openings 34; in this example there are two sample vessels 40 in each segment 30. The sample size can be adjusted by changing the length of the sample tubes. Prototypes sample sizes are in the order of 50-10OmL.

The two halves 31 and 32 of each segment are symmetrical and formed with integral extensions such as 35, slots such as 36 and tongues and other formations (not shown) to enable the two halves to fit together. Then the two halves can be secured together with screws or any other convenient fastening to achieve the required structural integrity and strength. The rack segments 30 are identical in design and the sample vessels 40 are held an equal distance from one another to simplify the control sequence and reduce the chance of drive error. Referring now to Fig. 3, at the proximal and distal end of the racks there is a respective connecting assembly 50 and 60 that locks to each tier 21, 22 and 23 and holds the tiers apart. As seen more easily at the distal end 60, there are three terminating segments 61, 62 and 63 that fit to respective tiers. A vertical member 64 connects the terminating segments together and defines the height between each tier. The arrangement is similar at the proximal end. The vertical member 64 is the only member that must be replaced to form a sampler for vessels having a different lengths.

Referring to both Figs. 1 and 3, at the proximal end the connecting assembly 50 also connects to a pressure chamber 51 that houses an electric motor, battery and control electronics. A screw drive shaft 52 extends from the pressure chamber 51 along the length of the central tier 22 of the rack, and this shaft 52 carries a paddle 53. The paddle 53 is threaded internally to match the thread of the screw drive shaft 52, such that when shaft 52 is rotated by the electric motor the paddle 53 will move along the length of the shaft. A stabilizing rod 54 is also provided to maintain the orientation of the actuation paddle as it is advanced along shaft 52. It is important to properly calibrate the closure mechanism for the sample vessels to ensure each sample is collected at the correct time and place. It there is any doubt about the calibration of the mechanical arrangement of the rack, then an acoustic or vibration sensor may be incorporated into the pressure chamber 51 to sense closure event and enable the time and location to be accurately logged.

Each of the sample vessels 40 is shown, like the prior art Niskin bottles, to be open at both ends, with an upper cap 41 and a lower cap 42. An internal mechanism (not shown) is arranged to automatically close both caps when they are released. In this example both caps are shown with a tie 43/44 extending from the top of the cap 41/42 to a catch 45 located on the middle tier 22.

In use the DC motor is selectively activated by the controller to advance paddle 53 along the length of screw drive shaft 52. As paddle 53 encounters each catch 45 the ties 43/44 are released allowing the vessels 40 to close (at both ends) and so collect a sample. In Fig. 3 it is seen that the paddle 53 has been advanced beyond the first two vessels, and that first two samples 60 and 61 have been collected. The remaining four vessels 40 are still open. Applications involving spring or elastic loaded components are expected, and in these cases the paddle and screw drive will be designed to be able to exert sufficient force to actuate the closing mechanisms. Rack Extension

Sample units can be added to the sampler in pairs by joining additional rack segments 30. The only components that must be replaced when the sampler size is altered are the screw drive shaft 52 and stabilizing rod 54. A large number of potential deployment platforms can be catered for with only a few different sampler lengths, screw drive shafts and stabilizing rods. Several standard lengths of these items can be cut at low cost and kept in reserve. Industrial Application

Referring now to Fig. 4, the sampler 10 is suitable to be mounted onboard a mobile science platform 100, such as an Autonomous Underwater Vehicle (AUV) or a remotely operated underwater vehicle (ROV), and to take discrete marine water samples on demand. The apparatus will typically be arranged so that the sample vessels are arranged in the direction of travel. In this way the water flows through them and an accurate representative sample is obtained at the moment of closure.

The platform 100 will generally determine if and when a sample is to be acquired, and will command the sampler 10 to acquire one or more samples. Acquisition of the samples can be triggered when any set of conditions are met, and with full autonomy. There is no restriction on which sensor or group of sensors 120 can be used to trigger the sampler, however some examples of environmental variables that may be monitored to determine where to take samples include local fluid salinity, temperature, turbidity, iron content, pressure, fish population activity, electrical conductivity, chlorophyll and acidity; as well as other metrics such as time. Many other types of sensors could be usefully employed by the apparatus.

The acquisition of each sample may be automated, depending on a range of predetermined factors programmed into the controller. The factors may include time as well as environmental inputs such as temperature, salinity, pressure and turbidity. Suitable sensors may be arranged with the sampler 10 to enable sophisticated sample collection regimes to be implemented.

The deployment platform 100 is ultimately responsible for sending requests to acquire a sample to the sampler, however any type of input to the deployment platform can be selected to achieve this, including a remote manual trigger from a user 130. On receipt of a request to sample, the control system 140 within the sampler will run the DC motor 150 and count rotations of the threaded shaft to ensure that the actuation paddle has moved a sufficient distance to trigger the next sample unit in the sequence. The offshore oil and gas industry make up the majority of the market for remote underwater vehicles(ROVs). This is a growing market resulting from an increased reliance on offshore platforms for oil production. ROVs are also used in aquaculture, which consists of high density farming with associated bacterial and water chemistry problems. A combined water sampler and sensor package, with an array of sensors such as DO, pH, temperature, conductivity can easily be strapped to any given ROV for use in these industries.

Variants Although the invention has been described with reference to a particular example, many modifications and variants are self-evident to the skilled reader. For instance, the number of tiers and segments may be varied to any number. Any mechanism can be used to trigger closure of the sample vessels, so long as it permits the actuation paddle to pass and be triggered by the passing of the paddle. The paddle itself could be of any shape and size, and could be fabricated from a wide range of materials depending on the application. The motor could be aligned parallel with the sample vessels, which would reduce overall length, and generally many other configurations of the apparatus would fall within the scope of the invention.

Claims

CLAIMS:

1. An immersible apparatus for collecting fluid or gas samples, comprising a rack, along the length of which are stations for securing respective self-contained sample vessels, and a mechanism arranged along the rack for selectively or sequentially collecting a sample at each station.

2. An immersible apparatus according to claim 1, wherein a sample collecting vessel is mounted at each station, and the mechanism operates to open or close each sample vessel along the rack.

3. An immersible apparatus according to claim 1 or 2, wherein the apparatus is linear.

4. An immersible apparatus according to claim 1 or 2, wherein the rack is of any shape not limited to linear, circular or rectangular

5. An immersible apparatus according to claim 3 or 4 wherein the apparatus is modular.

6. An immersible apparatus according to claim 5, wherein an instantiation of the apparatus has a predetermined number of stations.

7. An immersible apparatus according to claim 1, wherein the apparatus is associated with one or more sensors that provide signals for activating the opening or closing of the sample vessels.

8. An immersible apparatus according to claim 7, wherein the one or more sensors are selected from but not restricted to the following group

a temperature sensor,

a salinity sensor,

a pH sensor,

a turbidity sensor,

a dissolved oxygen sensor,

a depth sensor,

an iron content sensor, a fish activity sensor,

an electrical conductivity sensor,

a chlorophyll sensor,

a time sensor, and

a pressure sensor.

9. An immersible apparatus according to claim 2, wherein the sample collecting vessels have a capacity between 5OmL and 10OmL.

10. A robotic platform, equipped with an immersible apparatus and sensors according to claim 7, wherein opening or closing of the fluid collecting vessels takes place under control from the platform.

11. A robotic platform according to claim 10, wherein the platform is an Autonomous Underwater Vehicle (AUV).

12 A robotic platform according to claim 10, wherein the platform is a Remotely Operated Vehicle (ROV). 13 A robotic platform according to claim 10, wherein the platform may be tethered or attached to any vehicle