Liquid sampling apparatus

Abstract

This invention relates to liquid sampling apparatus for taking liquid samples from liquid storage containers. The liquid sampling apparatus has a housing defining a sampling chamber, variable flow control means operable to control liquid infilling, and filling and emptying valve means operable to provide both filling and emptying of the liquid sampling apparatus from the bottom of the sampling apparatus, thereby obtaining a representative sample of liquid from the entire column of liquid including the bottom of the storage container. The filling and emptying valve means is located in the base cap of the sampling apparatus.

Description

[0001] Liquid Sampling Apparatus

[0002] The present invention relates to liquid sampling apparatus. In particular, but not exclusively, it relates to apparatus for obtaining a representative liquid sample from along the entire depth range of a relatively shallow body of liquid.

[0003] International Patent Application No. WO 2006 / 125966 describes sampling apparatus to sample bodies of liquid, for example oil, commonly held in large storage tanks capable of holding more than a thousand cubic metres of liquid and often being 30-40m high. The apparatus described therein obtains a representative sample of a column of liquid from along the entire depth range of the storage tank, irrespective of the depth of the tank and hence pressure applied to the sample during sampling at great depth, which affects the sample filling rate. This type of apparatus fills from the bottom and the sample can be either decanted from the top of the sampler by removal of the top cap or alternatively the sampler remains sealed and the entire sampler containing the liquid sample is sent to a laboratory for sample analysis. Before sampling a key member must be inserted into the top of the sampling apparatus to allow air to escape from the device during sampling. When sampling is completed and the sampling apparatus is removed from the liquid the key member is unscrewed to seal the top of the device. Once at a laboratory, when analysis is required further separate valve means is inserted again into what was the top end of the sampling apparatus and the liquid sample is drained through the valve means into the analysing chamber. In this apparatus the liquid sample fills from the bottom but empties from the top using additional valve means. The sampling apparatus is not therefore a self-contained unit that fills and empties without the insertion of additional valve release members.

[0004] Within the oil industry particularly bottom sampling is important because the base of a tank usually comprises degrading product affected by microbial action, sludge or water. This degrading product could affect the overall composition and quality of the liquid / oil.

[0005] UK Patent No. 2170477 describes a sampling device operable to obtain a liquid sample from 0-35cm above the bottom of a tank; a so-called bottom sampler. The liquid sample is removed from the bottom sampler by inverting the sampler and decanting the liquid sample via a top cap spout. However, although the bottom sampler fills from the bottom of the device and thereby obtains a sample from the bottom of the tank, it does not also provide a representative liquid sample from along the length of the liquid column depth it passes through, as the sampler only starts to fill when a valve is activated on touching the tank bottom.

[0006] Neither of the above patent applications describe a device able to obtain a liquid sample from the length of the liquid column, which sample also includes liquid sample from close to the bottom of the tank. In relatively shallow liquid holding tanks, say of 3 -4m depth, the length of a sampling device which fills from the top becomes important relative to the depth of tank. In such instances with a top filling device no liquid sample can be taken from below the top inlet opening, so the obtained sample is missing liquid from the length of the device. A truly representative sample is therefore not obtained. Shorter, fatter top filling sampling devices are not suitable as the sampling aperture for the sampling device to be inserted into is often only 2 inches in diameter.

[0007] Therefore, a device that fills from the bottom at a flow rate independent of depth is advantageous. Furthermore, it is particularly advantageous to have a device that fills from and also empties from the bottom of the device, unlike previous devices. In addition, it is advantageous once sampling is finished for the sampling apparatus to empty without requiring the insertion of additional release means, thereby providing self-contained sampling apparatus.

[0008] Self-contained sampling apparatus is required because the sampler is dropped into a liquid storage tank and is required to allow liquid ingress at depth without the need for physical manual adjustment to the sampler to control inlet valves or outlet valves or external actuators located outside of or separately from the sampler itself, such as in the pre-pressurised sampling equipment of US Patent No. 9,116,082, for example.

[0009] It is believed that the improved advantageous features of the sampling apparatus described herein will also render this filling and emptying means suitable to replace or substitute for the design of current sampling apparatus able to provide running samples (samples obtained from top to bottom of a liquid column and back) or all-level samples (samples obtained from top to bottom of a liquid sample) taken from the large storage tanks described above. The feature of filling and emptying from the bottom of sampling apparatus such as described in this application offers the advantage of being able to sample from the top of the liquid column to the dead bottom of the tank, which is not seen in samplers currently in use.

[0010] Sampling devices can be used alone with a rope or cable for open sampling or in combination with a winder that lowers the sampling device from within the winder into the liquid holding tank, obtains a sample, retrieves the sampler into the winder from the tank and empties the sampling device from within the winder, all as a closed sampling system. A closed sampling system is important in order to prevent escape of volatile material to the atmosphere and also to protect the operator for health and safety reasons. It is highly desirable for the sampling device to have a bottom emptying mechanism that cooperates with the capture and emptying mechanism of such closed system winders.

[0011] The present invention provides liquid sampling apparatus being a sampling device comprising a housing defining a sampling chamber, a base cap located at the base of the sampling chamber and an end cap located at the top of the sampling chamber, variable flow control means operable to control liquid infilling, and filling and emptying valve means operable to provide both filling and emptying of the liquid sampling apparatus, the filling and emptying valve means being located in the base cap.

[0012] Preferably the variable flow control means comprises rotationally movable means operable to vary an opening size and thereby affect the speed of infilling of liquid into the sampling chamber.

[0013] Advantageously the rotationally movable means operable to vary an opening size and thereby affect the speed of infilling of liquid into the sampling chamber comprises two rotationally movable sections rotationally movable coaxially in opposing directions. Alternatively, the rotationally movable means comprises a rotationally movable member operable to move a further member longitudinally to vary an opening size and thereby affect the speed of infilling of liquid into the sampling chamber.

[0014] Preferably the variable flow control means comprises a top valve section and a bottom valve section. More preferably the top valve section comprises bayonet spindle means and flow control shaft means. Preferably the bottom valve section comprises receiving recess means. Even more preferably the flow control shaft means is longitudinally movable into co- operation with the receiving recess means by means of a rotational member, being thereby operable to vary the size of an opening in the receiving recess means and thereby affect the speed of infilling of liquid into the sampling chamber. Most preferably the flow control shaft means is pin means co-operating with pin recess means. Even more preferably the pin means is coaxially longitudinally movable with respect to the pin recess means. Preferably the pin recess means has an opening in the base of the recess to allow liquid flow therethrough. Preferably the rotational member is a rotationally movable ring.

[0015] Preferably the filling and emptying valve means comprises a probe movable from a first filling position to a second emptying position. Even more preferably the probe is movable within the sampling apparatus from the first position to the second position. Advantageously the filling and emptying valve means is located towards the bottom of the sampling apparatus, and more advantageously is located at the bottom of the sampling apparatus.

[0016] Even more preferably the probe comprises removably detachable sections, one section of which probe provides housing means for valve control means. Advantageously the valve control means is a solid ball, which solid ball is movable from a position allowing liquid infill to a position preventing liquid infill or outflow through liquid flow passage means. Should 3D printing be the manufacturing method the probe may not comprise detachable sections.

[0017] Preferably the filling and emptying valve means is provided with means operable to respond to action, usually compression, to move the filling and emptying valve means to a second emptying position in which liquid outlet means are exposed to provide for liquid egress of the sample housing.

[0018] Advantageously the means operable to respond to action to move the filling and emptying valve to the second position is shaped to co-operate with the neck of a sample vessel or the emptying means of an enclosing closed sampling winder.

[0019] The invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:

[0020] FIGURE 1 is a plan view of one embodiment of sampling apparatus according to the invention,

[0021] FIGURE 2 is a cross section along A-A of the apparatus of Figure 1, FIGURE 3 is various perspective views of variable flow control means of the sampling apparatus,

[0022] FIGURE 4 is a plan view of the base cap and filling and emptying means in a first position,

[0023] FIGURE 5 is a cross section along B-B of Figure 4,

[0024] FIGURE 6 is a plan view of the base cap and filling and emptying means in a second position,

[0025] FIGURE 7 is a cross-section along section C-C of Figure 6,

[0026] FIGURE 8 is a plan view of an alternative attachment means of a sampling apparatus according to a first embodiment of the invention shown in Figure 1,

[0027] FIGURE 9 is a perspective view of an alternative variable flow control means according to the invention,

[0028] FIGURE 10 is an exploded perspective view of the variable flow control means of Figure 9,

[0029] FIGURE 11 is a plan view of the variable flow control means of Figures 9 and 10, FIGURE 12 is a cross section along section D-D of the variable flow control means of Figure 11 ,

[0030] FIGURE 13 is a plan view of a second embodiment of sampling apparatus according to the invention, and

[0031] FIGURE 14 is a cross-section along section E-E of the sampling apparatus of Figure 13.

[0032] Referring to Figures 1-7, in one embodiment of the invention the sampling apparatus or sampling device 1, typically known in the industry as a sampler, can or thief, comprises a sample housing 2 defining a sampling chamber, a base cap 3 and an end cap 4. In use, the sampling apparatus 1 is lowered vertically into a body of liquid to obtain a sample thereof. The base cap 3 is located at the base of the sample housing 2 and the end cap 4 is located at the top of the sample housing 2. End cap 4 is provided with attachment means operable to connect with a rope or cable. The attachment means may be a hook 40 as shown in Figures 1 and 2 or an eye 41 as shown in Figure 8. The main body of the sample housing is preferably cylindrical, although such is not essential. The sample housing 2, base cap 3 and end cap 4 are preferably each made of stainless steel, although they may each be made of any other suitable material depending on the liquid to be sampled. The sample housing 2 is provided with an aperture 5 at the top of the housing and an aperture 6 at the base of the sample housing 2. A threaded section 7 at the top end of the sample housing receives the end cap 4 and a threaded section 8 at the bottom end of the sample housing 2 receives the base cap 3. This arrangement provides a self-contained or stand alone sampling apparatus, typically known as a sampler. End cap 4 comprises variable flow control means operable to provide a desired speed of outflow of air and hence infilling liquid speed as the liquid enters the sample housing 2 via base cap 3. The speed of liquid infilling can be adjusted depending on the viscosity of the liquid to be sampled. In this embodiment the variable flow control means comprises a top valve section 9 and bottom valve section 10 rotationally movable relative to oneanother, in this instance rotationally movable about the longitudinal axis of the sample housing 2. Top valve section 9 has an opening 11 extending through it. Bottom valve section 10 also has an opening 12 extending through it. By rotating the top valve section 9 and bottom valve section 10 relative to one another the amount of overlap of each opening 11, 12 in each section 9, 10 can be varied to adjust the outflow of air and hence infilling liquid speed. One or more openings can be provided in each of the top valve section and bottom valve section, each of which top valve section openings co-operate with bottom valve section openings to provide variable flow control. Other flow control means may be suitable for controlling the inflow of liquid, such as that described below with reference to Figures 9 to 12. In use the operator is required to adjust the variable flow control means to obtain the right filling rate for different depths and viscosities.

[0033] Base cap 3 has an opening 13 extending therethrough from one surface to another surface of base cap 3. In this embodiment the opening extends from an upper surface to a lower surface of the base cap. The lower surface of base cap 3 is smoothly profiled to a narrower diameter at the lower end thereof than the outer diameter of the sample housing 2 to minimise the disruption to the liquid column as the sampling apparatus 1 descends through the liquid. The upper surface of the base cap 3 is provided with a recess 14 providing a seat for filling and emptying valve means 15. Within base cap opening 13 is provided sealing means operable to prevent liquid flow between the sampling chamber of sample housing 2 and liquid travelling through filling and emptying valve means 15. In this embodiment, in the upper section of base cap opening 13 an ‘O’ ring 16 is provided in a recessed groove and in the lower section of base cap opening 13 ‘O’ rings 17 and 18 are provided in recessed grooves. The ‘O’ rings provide resilient sealing means. The sealing means is arranged to provide a seal on either side of liquid outlet means located in filling and emptying valve means 15, when filling and emptying valve means 15 is in a first position.

[0034] Filling and emptying valve means 15 extends from sample housing 2 through opening 13 to project beyond base cap 4 and provide access to the liquid to be sampled. In this embodiment filling and emptying valve means is a probe comprised of lower probe 19 and upper probe 20 which are removably detachable from one another by means of a screw thread. Lower probe 19 at the upper end thereof has a wider diameter than the lower end thereof to provide housing means for non-retum valve means. Housing means is a chamber 21 housing a solid ball 22 capable of acting as valve control means. In one position of the probe chamber 21 of the probe is seated within recess 14 provided in the upper surface of base cap 3. Solid ball 22 is provided with a seat inside chamber 21 at the top of lower probe 19. The solid ball 22 may be PTFE, for example.

[0035] Upper and lower probes 19, 20 are provided with a passage 23 extending therethrough from top opening 24 to bottom opening 25. At the lower end of lower probe 19 a screw thread is provided to receive probe end cap 26. Spring 27 is arranged around the lower end of the probe below base cap 3. When compressed spring 27 sits within recess 28 at the bottom of base cap 3 and recess 29 at the top of probe end cap 26. Passage 23 also extends through probe end cap 26 to connect the sampling chamber of sample housing 2 with the liquid to be sampled. Probe end 30 provides an inlet and outlet for the liquid sample. In this embodiment probe end cap 26 of the probe is shaped to provide sampling apparatus capture means when sampling apparatus 1 is used for closed sampling in combination with a winder having an emptying system that captures the sampling apparatus 1 and empties it via an emptying device of the winder. Regardless of the shape, in other embodiments probe end cap 26 or indeed the opening 25 of lower probe 19 can function to open the sampling apparatus even when not used in combination with a winder, as will be described below.

[0036] The probe of filling and emptying valve means 15 is also provided with liquid outlet means provided by outlet apertures 31 and 32. The number or size of liquid outlet apertures provided will depend on the viscosity of the liquid to be sampled and how quickly it is desired to empty the sampling chamber. The probe is movable within the sampling apparatus 1, also known as a sampling device, from a first position shown in Figures 1, 2, 4 and 5 to a second position shown in Figures 6 and 7. The first position allows liquid to enter the sampling chamber. The second position allows liquid to leave the sampling chamber. In operation, in the first filling position as the sampling apparatus is lowered into the liquid to be sampled air in the sampling chamber is forced upwards along passage 23 displacing solid ball 22 from the seat within chamber 21. Liquid travels up passage 23 via probe end 30 around solid ball 22 and enters the sampling chamber via top opening 24 thereby defining inflow passage means. With careful selection of the opening size of the variable flow control means before starting sampling the sampling chamber fills during descent and ascent. The weight of the solid ball 22 and liquid above it as the sampler is raised causes ball 22 to seat itself inside chamber 21 and act as a closed valve preventing liquid sample from leave the sampling apparatus when the sampler is lifted out of the liquid.

[0037] Once the sampling apparatus is retrieved from the storage tank the bottom emptying mechanism of the probe can be compressed into the second emptying position as shown in Figures 6 and 7, by pressure against the neck of a bottle for decanting purposes, for example in open sampling. Alternatively, the probe end 26 is captured and compressed by emptying means of an enclosing winder in a closed sampling situation. When probe end 26 of the probe is compressed against spring 27 outlet apertures 31 and 32 of liquid outlet means move into the liquid in sample housing 2 and provide outflow passage means for the emptying of the liquid sample held in the sampling chamber. In addition, the liquid held in upper probe 20 can exit around solid ball 22 via outlet 32, which is still open even when the solid ball 22 falls into or towards its seat within chamber 21. Thereby, all the sample held within sample housing 2 is retrieved providing a fully representative sample of the liquid column. Inflow passage means and outflow passage means are essentially the same passage and are provided within filling and emptying valve means 15.

[0038] In further embodiments not described in detail herein it is clear that upper probe 20 can extend for a longer distance into the sampling chamber if the depth of the storage tanks to be sampled necessitates increased fill rate control. The head of pressure between the air outlet 11, 12 in end cap 4 and opening 24 at the top of probe 20 can also help control the liquid sample filling rate depending on the type of sample and the depth of sampling. The upper probe 20 may extend up to say 75%-80% of the length of the sampling chamber if the storage tank is 20-30m deep. The length of the upper probe 20 ensures that the rate of filling of the sampling chamber is roughly the same at Im depth as at 30m depth. In essence, current running sampler apparatus can be modified to incorporate the filling and emptying means of the current invention to provide bottom filling and emptying of such sampling apparatus.

[0039] Figures 13 and 14 show a second embodiment of the invention with alternative variable flow control means. Sampling apparatus or sampling device 100, typically known in the industry as a sampler, can or thief, comprises a sample housing 200 defining a sampling chamber, a base cap 300 and an end cap 400. In use, the sampling apparatus 100 is lowered vertically into a body of liquid to obtain a sample thereof. The base cap 300 is located at the base of the sample housing 200 and the end cap 400 is located at the top of the sample housing 200. End cap 400 is provided with attachment means operable to connect with a rope or cable. The attachment means in this embodiment is operable to connect with a rope or cable. The attachment means may be a bayonet hook 40 as shown in Figures 1 and 2 or an eye 41 as shown in Figure 8. The alternative variable flow control means of this embodiment is shown in perspective view in Figure 9, in plan view in Figure 11 and in cross-section along Section D-D in Figure 12. The main body of the sample housing is preferably cylindrical, although such is not essential. Again, the sample housing 200, base cap 300 and end cap 400 are preferably each made of stainless steel, although they may each be made of any other suitable material depending on the liquid to be sampled.

[0040] The sample housing 200 is provided with an aperture 500 at the top of the housing and an aperture 600 at the base of the sample housing 200. A threaded section 700 at the top end of the sample housing receives the end cap 400 and a threaded section 800 at the bottom end of the sample housing 200 receives the base cap 300. This arrangement provides a self- contained or stand alone sampling apparatus, typically known as a sampler. End cap 400 comprises variable flow control means 60 shown in Figures 9 and 10 operable to provide a desired speed of outflow of air and hence infilling liquid speed as the liquid enters the sample housing 200 via base cap 300. The speed of liquid infilling can be adjusted depending on the viscosity of the liquid to be sampled.

[0041] In this embodiment the variable flow control means 60 comprises a top valve section 900 comprising spindle bayonet means 61 which has bayonet receiving means 62 at the upper end thereof for attaching the sampler to the tape end of a tape located in a winder, the tape end being usually a hook swivel, and a bottom valve section 1000. Top valve section 900 houses flow control shaft means being pin member 70 with cross-member 75, spring 80 arranged around the lower part of pin member 70 and knurled ring 90. Pin member 70 is received through opening 64 in the lower section of spindle bayonet means 61 of top valve section 900. Bottom valve section 1000 is provided with recess means in the upper surface of the bottom valve section 1000. Recess means is a reciprocal recess 65 shaped or profiled to receive the lower shaped / profiled end 71 of pin member 70. Recess 65 has an opening 66 at the apex of the recess 65, which opening 66 allows air to leave the housing chamber. Pin member 70 is longitudinally movable relative to recess 65 in bottom valve section 1000 by turning knurled ring 90 about threaded section 63 which forces the cross-member 75 of pin member 70 so that the shaped / profiled end 71 of pin member 70 moves towards recess 65. Pin member 70 is longitudinally movable towards recess 65, in this instance along the coaxial longitudinal axis of the sample housing 200. By rotating knurled ring 90 cross-member 75 of pin member 70 reacts against spring 80 so that the shaped end 71 of pin member 70 is movable towards and away from, i.e. relative to, recess 65 in bottom valve section 1000 so that the distance between shaped end 71 of pin member 70 and the opening 66 of recess 65 can be varied to adjust the outflow of air and hence infilling liquid speed, thereby providing variable flow control. In use the operator is required to adjust the variable flow control means to obtain the preferred filling rate for different depths and viscosities. Figures 9 and 10 show four indicator numbers identifying suitable pin cross member positions for optimal flow conditions for different liquid types to be sampled. The fill time for each indicator position may also be indicated in seconds, if the liquid to be sampled is known.

[0042] Base cap 300 has an opening 1300 extending therethrough from one surface to another surface of base cap 300. In this embodiment the opening extends from an upper surface to a lower surface of the base cap. The lower surface of base cap 300 is smoothly profiled to a narrower diameter at the lower end thereof than the outer diameter of the sample housing 200 to minimise the disruption to the liquid column as the sampling apparatus 100 descends through the liquid. The upper surface of the base cap 300 is provided with a recess 1400 providing a seat for filling and emptying valve means 1500. Within base cap opening 1300 is provided sealing means operable to prevent liquid flow between the sampling chamber of sample housing 200 and liquid travelling through filling and emptying valve means 1500. In this embodiment, in the upper section of base cap opening 1300 an ‘O’ ring 1600 is provided in a recessed groove and in the lower section of base cap opening 13 ‘O’ rings 1700 and 1800 are provided in recessed grooves. The ‘O’ rings provide resilient sealing means. The sealing means is arranged to provide a seal on either side of liquid outlet means located in filling and emptying valve means 1500, when filling and emptying valve means 1500 is in a first position.

[0043] Filling and emptying valve means 1500 extends from sample housing 200 through opening 1300 to project beyond base cap 400 and provide access to the liquid to be sampled. In this embodiment filling and emptying valve means is a probe comprised of lower probe 1900 and upper probe 2000 which are removably detachable from one another by means of a screw thread. Upper probe 2000 in this embodiment has a tube length longer than that of upper probe 20 in the first embodiment (about half the length of the sample housing). The tube length may be even longer than is shown in Figure 14. Lower probe 1900 at the upper end thereof has a wider diameter than the lower end thereof to provide housing means for nonreturn valve means. Housing means is a chamber 2100 housing a solid ball 2200 capable of acting as valve control means. In one position of the probe, chamber 2100 of the probe is seated within recess 1400 provided in the upper surface of base cap 300. Solid ball 2200 is provided with a seat inside chamber 2100 at the top of lower probe 1900. The solid ball 2200 may be PTFE, for example.

[0044] Upper and lower probes 1900, 2000 are provided with a passage 2300 extending therethrough from top opening 2400 to bottom opening 2500. At the lower end of lower probe 1900 a screw thread is provided to receive probe end cap 2600. Spring 2700 is arranged around the lower end of the probe below base cap 300. When compressed spring 2700 sits within recess 2800 at the bottom of base cap 300 and recess 2900 at the top of probe end cap 2600. Passage 2300 also extends through probe end cap 2600 to connect the sampling chamber of sample housing 200 with the liquid to be sampled. Probe end 3000 provides an inlet and outlet for the liquid sample. In this embodiment probe end cap 2600 of the probe is shaped to provide sampling apparatus capture means when sampling apparatus 100 is used for closed sampling in combination with a winder having an emptying system that captures the sampling apparatus 100 and empties it via an emptying device of the winder. Regardless of the shape, in other embodiments probe end cap 2600 or indeed the opening 2500 of lower probe 1900 can function to open the sampling apparatus even when not used in combination with a winder, as will be described below. The probe of filling and emptying valve means 1500 is also provided with liquid outlet means provided by outlet apertures 3100 and 3200. The number or size of liquid outlet apertures provided will depend on the viscosity of the liquid to be sampled and how quickly it is desired to empty the sampling chamber.

[0045] Like the first embodiment of the invention, the probe is movable within the sampling apparatus or sampling device / sampler 1000 from a first position as shown in Figures 1, 2, 4 and 5 to a second position shown in Figures 6, 7, 13 and 14. The first position allows liquid to enter the sampling chamber. The second position allows liquid to leave the sampling chamber. In operation, in the first filling position as the sampling apparatus is lowered into the liquid to be sampled air in the sampling chamber is forced upwards along passage 2300 displacing solid ball 2200 from the seat within chamber 2100. Liquid travels up passage 2300 via probe end 3000 around solid ball 2200 and enters the sampling chamber via top opening 2400 thereby defining inflow passage means. With careful selection of the opening size of the variable flow control means before starting sampling the sampling chamber fills during descent and ascent. The weight of the solid ball 2200 and liquid above it as the sampler is raised causes ball 2200 to seat itself inside chamber 2100 and act as a closed valve preventing liquid sample from leave the sampling apparatus when the sampler is lifted out of the liquid.

[0046] Once the sampling apparatus is retrieved from the storage tank the bottom emptying mechanism of the probe can be compressed into the second emptying position, exactly as shown in Figures 13 and 14, by pressure against the neck of a bottle for decanting purposes, for example in open sampling. Alternatively, the probe end 2600 is captured and compressed by emptying means of an enclosing winder in a closed sampling situation. When probe end 2600 of the probe is compressed against spring 2700 outlet apertures 3100 and 3200 of liquid outlet means move into the liquid in sample housing 200 and provide outflow passage means for the emptying of the liquid sample held in the sampling chamber. In addition, the liquid held in upper probe 2000 can exit around solid ball 2200 via outlet 3200, which is still open even when the solid ball 2200 falls into or towards its seat within chamber 2100. Thereby, all the sample held within sample housing 200 is retrieved providing a fully representative sample of the liquid column. Inflow passage means and outflow passage means are essentially the same passage and are provided within filling and emptying valve means 1500.

Claims

CLAIMS1. Liquid sampling apparatus comprising a housing defining a sampling chamber, a base cap located at the base of the sampling chamber and an end cap located at the top of the sampling chamber, variable flow control means operable to control liquid infilling, and filling and emptying valve means operable to provide both filling and emptying of the liquid sampling apparatus, the filling and emptying valve means being located in the base cap.

2. Liquid sampling apparatus according to Claim 1, wherein the variable flow control means comprises rotationally movable means operable to vary an opening size and thereby affect the speed of infilling of liquid into the sampling chamber.

3. Liquid sampling apparatus according to Claim 1 or 2, wherein the variable flow control means comprises a top valve section and a bottom valve section .

4. Liquid sampling apparatus according to Claim 3, wherein the top valve section comprises bayonet spindle means and flow control shaft means.

5. Liquid sampling apparatus according to Claim 3 or 4, wherein the bottom valve section comprises receiving recess means.

6. Liquid sampling apparatus according to any one of Claims 1-5, wherein the flow control shaft means is longitudinally movable into co-operation with receiving recess means by means of a rotational member, being thereby able to vary the size of an opening in the receiving recess means and thereby affect the speed of infilling of liquid into the sampling chamber.

7. Liquid sampling apparatus according to any one of the preceding claims, wherein the flow control shaft means is is pin means co-operating with pin recess means.

8. Liquid sampling apparatus according to Claim 7, wherein the pin means is movable with respect to the pin recess means.

9. Liquid sampling apparatus according to Claim 8, wherein the pin means is coaxially longitudinally movable with respect to the pin recess means.

10. Liquid sampling apparatus according to Claim 9, wherein the pin recess means has an opening in the base of the recess to allow liquid flow therethrough.

11. Liquid sampling apparatus according to Claim 10, wherein the rotational member is a rotationally movable ring.

12. Liquid sampling apparatus according to any one of the preceding claims, wherein the filling and emptying valve means comprises a probe movable from a first filling position to a second emptying position.

13. Liquid sampling apparatus according to any one of the preceding claims, wherein the filling and emptying valve means is located towards or at the bottom of the sampling apparatus.

14. Liquid sampling apparatus according to Claim 12, wherein the probe comprises removably detachable sections.

15. Liquid sampling apparatus according to any one of Claims 12-14, wherein one section of said probe provides housing means for valve control means.

16. Liquid sampling apparatus according to Claim 15, wherein the valve control means is movable from a position allowing liquid infill to a position preventing liquid infill or outflow though liquid flow passage means.

17. Liquid sampling apparatus according to any one of the preceding claims, wherein the filling and emptying valve means is provided with means operable to respond to action to move the filling and emptying valve means to a second emptying position in which liquid outlet means are exposed to provide for liquid egress of the sample housing.

18. Liquid sampling apparatus according to Claim 17, wherein the means operable to respond to action to move the filling and emptying valve to the second position is shaped to co-operate with the neck of a sample vessel or the emptying means of an enclosing closed sampling winder.

19. Liquid sampling apparatus substantially as described herein with reference to any one of the accompanying diagrammatic drawings.

20. Liquid sampling apparatus variable flow control means operable to control the flow of a liquid therethrough comprising rotationally movable means operable to vary an opening size and thereby affect the speed of infilling of liquid into the sampling chamber.

21. Liquid sampling apparatus variable flow control means according to Claim 20, wherein the rotationally movable means operable to vary an opening size and thereby affect the speed of infilling of liquid into the sampling chamber comprises two rotationally movable sections rotationally movable coaxially in opposing directions.

22. Liquid sampling apparatus variable flow control means according to Claim 20, wherein the rotationally movable means comprises one rotationally movable member operable to move a further member longitudinally to vary an opening size.

23. Liquid sampling apparatus variable flow control means according to any one of Claims 20-22, wherein the variable flow control means comprises a top valve section and a bottom valve section.

24. Liquid sampling apparatus variable flow control means according to Claim 23, wherein the top valve section comprises bayonet spindle means and flow control shaft means.

25. Liquid sampling apparatus variable flow control means according to Claim 20 or any one of Claims 22-24, wherein the bottom valve section comprises receiving recess means.

26. Liquid sampling apparatus variable flow control means according to Claim 20 or any one of Claims 22-25, wherein the flow control shaft means is longitudinally movable into cooperation with the receiving recess means by means of a rotational member, being thereby operable to vary the size of an opening in the receiving recess means and thereby affect the speed of infilling of liquid into the sampling chamber.

27. Liquid sampling apparatus variable flow control means according to Claim 26, wherein the flow control shaft means is pin means co-operating with pin recess means.

28. Liquid sampling apparatus variable flow control means according to Claim 27, wherein the pin means is coaxially longitudinally movable with respect to the pin recess means.

29. Liquid sampling apparatus variable flow control means according to Claim 28, wherein the pin recess means has an opening in the base of the recess to allow liquid flow therethrough.

30. Liquid sampling apparatus variable flow control means according to any one of Claims 26 - 29, wherein the rotational member is a rotationally movable ring.

31. A method of sampling liquid held in a liquid container, wherein sampling apparatus according to the any one of the preceding claims is lowered into the liquid container to a prescribed depth, liquid enters the sample housing through an opening at the bottom of the sampling apparatus forcing air from the sampling chamber out of the sampling apparatus via variable flow control means at the top of the sampling apparatus, which variable flow control means varies the infilling rate of the liquid into the sampling chamber, the sampling apparatus is held at the prescribed depth for a prescribed time to allow filling, the filling and emptying valve means being in a first filling position during filling, the sampling apparatus after filling being lifted out of the sampling chamber, the filling and emptying valve means being automatically closed during the lifting of the sampler from the liquid container by valve control means, and the filling and emptying valve means then being moved into a second emptying position to allow the sampled liquid to leave the sampling chamber through the same opening as during filling.

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