Sample Collecting Device

FIELD OF THE INVENTION

[01] The present invention relates to a sample collecting device, in particular to a sample collecting device which can reduce the high pressure of a gaseous sample.

BACKGROUND OF THE INVENTION

[02] A gas chromatography (GC) instrument separates various components in a sample in the gaseous state through chromatographic columns and detects the concentration of each component. The GC analysis process is highly precise yet slow. If all components in the gaseous sample are defined in a standard spectrogram, it may be easily identified with a reference to the standard spectrogram; if a component doesn't match any reference in standard spectrogram, mass spectrography (MS, for short) is required for further analysis of the component.

[03] A gas chromatography instrument is relatively vulnerable to high pressure impact (a sudden increase or decrease of pressure) and liquid which may damage the expensive gas chromatography instrument. Without suitable protective means, the gas chromatography instrument cannot be used directly to analyze a gaseous sample of high pressure (carrier gas is normally in low pressure, thus a high pressure impact will be caused if a gaseous sample of high pressure is introduced into GC directly) or a gaseous sample containing components (e.g. water) which assume a liquid state under certain temperatures and pressures (e.g. ambient temperature and pressure). Therefore, the application scope of the instrument has been significantly limited.

[04] Therefore, there is a need to design a sample collecting device which can reduce the high pressure of a gaseous sample so as to protect the substance analyzer.

SUMMARY OF THE INVENTION [05] In one aspect, the present invention provides a sample collecting device comprising a first sampling chamber and a second sampling chamber, the sample collecting device has three operating states, in a first operating state, the first sampling chamber is in fluid communication with (directly or indirectly connected to) a source of gaseous sample

such that the first sampling chamber may be filled with the gaseous sample (e.g., a gaseous sample of high pressure); in a second operating state, the second sampling chamber is in fluid communication with both of the first sampling chamber and a low-pressure environment such that the gaseous sample in the first sampling chamber may expand naturally into the second sampling chamber and further be discharged into the low-pressure environment, therefore, the pressure of the gaseous sample remained in the first sampling chamber and the second sampling chamber is relatively low; in a third operating state, the first sampling chamber or the second sampling chamber is in fluid communication with both of an inert gas supply and a gaseous substance analyzer, and the gaseous sample in the first sampling chamber or the second sampling chamber is introduced (e.g. blown) into the gaseous substance analyzer by the gaseous substance from the inert gas supply.

[06] Said inert gas can be any gaseous substance that does not affect the analysis of said gaseous sample.

[07] Further, said inert gas works as a carrier gas in the third operating state.

[08] Further, said low-pressure environment is a space with a low-pressure, and the pressure in said low-pressure environment is preferred to be close to the pressure of said inert gas supply, thus minimize the impact of gaseous sample to said gaseous substance analyzer.

[09] In the third operating state, the gaseous samples in the first and second sampling chambers both have a low pressure; therefore either of them may be selected and introduced into the gaseous substance analyzer for analysis. Although such layout of the connections is not disclosed in the specific embodiments of the present invention, it is readily conceivable by those skilled in the art based on the teaching of the invention.

[10] Furthermore, more sampling chambers may be provided such that the high pressure gaseous sample in the first sampling chamber may expand into these chambers which harbor the low-pressure gaseous sample through the expansion of high-pressure sample. Afterwards, the gaseous sample with low-pressure in any one of the sampling chambers may be introduced into the gaseous substance analyzer, without departure from the scope of the invention.

[11] Further, in the third operating state, the second sampling chamber is in fluid communication with both of the inert gas supply and the gaseous substance analyzer respectively.

[12] The pressure of the source of gaseous sample is greater than that of the low-pressure environment. Further, by adjusting the volume of the first sampling chamber, the second sampling chamber and the connecting pipelines therebetween, it is ensured that the gaseous sample in the first sampling chamber may expand naturally into and fill the second sampling chamber.

[13] Further, in the first operating state, the first sampling chamber is also in fluid communication with an exhaust collecting system.

[14] Further, in the first operating state, the second sampling chamber is in fluid communication with both of the inert gas supply and the low-pressure environment respectively.

[15] Further, in the second operating state, the first sampling chamber is in fluid communication with the second sampling chamber.

[16] Further, in the third operating state, the first sampling chamber is in fluid communication with both of the inert gas supply and the low-pressure environment respectively.

[17] Further, during one operating cycle, the sample collecting device switches from the first operating state to the second operating state and further to the third operating state, and switches from the third operating state to the first operating state when the next sampling analysis is carried out.

[18] Further, the first and second sampling chambers may take any forms of a sampling chamber, such as a ring tube or a corrugated tube.

[19] Further, in the first and second operating states, the inlet of the gaseous substance analyzer is in fluid communication with the inert gas supply.

[20] Further, the inert gas supply can be any low-pressure gas flow having no influence on the analysis of gaseous sample, such as an inert gas flow. Further, it may be a nitrogen,

- A - argon or helium flow.

[21] Further, switch valves can be used, to switch the sample collecting device between said operating states by switching said switch valves.

[22] Further, two switch valves 52 and 53 are used in said sample collecting device as shown in Figure 1 to Figure 3.

[23] The switch valve 52 is provided with a first port 521 , a second port 522, a third port 523, a fourth port 524, a fifth port 525 and a sixth port 526. The switch valve 52 has two communication states, a first communication state in which the first port 521 is in fluid communication with the second port 522, the third port 523 is in fluid communication with the fourth port 524, and the fifth port 525 is in fluid communication with the sixth port 526; and a second communication state in which the first port 521 is in fluid communication with the sixth port 526, the second port 522 is in fluid communication with the third port 523, and the fourth port 524 is in fluid communication with the fifth port 525.

[24] The switch valve 53 has the same structure as that of the switch valve 52 and is provided with a first port 531, a second port 532, a third port 533, a fourth port 534, a fifth port 535 and a sixth port 536. When the switch valve 53 is in the first communication state, the first port 531 is in fluid communication with the second port 532, the third port 533 is in fluid communication with the fourth port 534, and the fifth port 535 is in fluid communication with the sixth port 536; and when it is in the second communication state, the first port 531 is in fluid communication with the sixth port 536, the second port 532 is in fluid communication with the third port 533, and the fourth port 534 is in fluid communication with the fifth port 535.

[25] In this embodiment, said operating state of the sample collecting device is decided by the combination of communication states of said two switch valves and state of a cut off valve.

[26] The first port 521 of the switch valve 52 is in fluid communication with the gaseous sample, the second port 522 is in fluid communication with a first port of the first sampling chamber 520, the third port 523 is in fluid communication with the inert gas supply with a cut off valve 55 disposed therebetween, the fourth port 524 is in fluid communication with the first port 531 of the switch valve 53, the fifth port 525 is in fluid

communication with the outlet of the first sampling chamber, and the sixth port 526 is in fluid communication with the high pressure exhaust collecting system.

[27] The second port 532 of the switch valve 53 is in fluid communication with the first port of the second sampling chamber 530, the third port 533 is in fluid communication with the inert gas supply, the fourth port 534 is in fluid communication with the inlet of the gaseous substance analyzer, the fifth port 535 is in fluid communication with the second port of the second sampling chamber 530, and the sixth port 536 is in fluid communication with the low-pressure environment.

[28] When the switch valve 52 is in the first communication state, the switch valve 53 is in the first communication state, and the cut off valve 55 is in an open state, the sample collecting device is in the first operating state. The high pressure gaseous sample enters into the exhaust collecting system via the first port 521, the second port 522 of the switch valve 52, the first sampling chamber 520, the fifth port 525 and the sixth port 526 of the switch valve 52, wherein the pressure of the high pressure exhaust collecting system is substantially the same as that of the gaseous sample. After a period of time, remainder gaseous substances in the first sampling chamber 520 is discharged to the exhaust collecting system and the first sampling chamber 520 is filled with the high pressure gaseous sample. Inert gas enters into the low-pressure environment via the third port 523 and the fourth port 524 of the switch valve 52, the first port 531 and the second port 532 of the switch valve 53, the second sampling chamber 530, and the fifth port 535 and the sixth port 536 of the switch valve 53, so as to discharge the remainder gaseous substances in the second sampling chamber 530 to the low-pressure environment. The inert gas enters into the gaseous substance analyzer through the third port 533 and the fourth port 534 of the switch valve 53 so as to discharge the remainder gaseous substances in the gaseous substance analyzer.

[29] When the switch valve 52 is switched to the second communication state, the switch valve 53 is kept in the first communication state, and the cut off valve 55 is shut down, the sample collecting device is in the second operating state. The high pressure gaseous sample enters into the exhaust collecting system via the first port 521 and the sixth port 526 of the switch valve 52. Since the first sampling chamber 520 is filled with the high pressure gaseous sample, while the second sampling chamber 530 is in fluid communication with the low-pressure environment, the pressure in the second sampling

chamber 530 is lower than that in the first sampling chamber 520. Therefore, the high pressure gaseous sample in the first sampling chamber 520 expands naturally into the second sampling chamber 530 via the fifth port 525 and the fourth port 524 of the switch valve 52, the first port 531 and the second port 532 of the switch valve 53, and expels the gaseous substance in the second sampling chamber 530 to the low-pressure environment through the fifth port 535 and the sixth port 536 of the switch valve 53. If the pressure of the high pressure gaseous sample goes beyond a certain range, a portion of the gaseous sample in the first sampling chamber 520 will also be discharged to the low-pressure environment via expanding. This process will continue till the pressure in the first sampling chamber 520 and the second sampling chamber 530 is substantially the same as that in the low-pressure environment. At this stage, the second sampling chamber 530 is filled with the low-pressure gaseous sample. Inert gas enters into the gaseous substance analyzer through the third port 533 and the fourth port 534 of the switch valve 53 so as to expel remainder gas in the gaseous substance analyzer.

[30] When the switch valve 52 is in the second communication state, the switch valve 53 is switched to the second communication state, and the cut off valve is switched to the open state, the sample collecting device is in the third operating state. The high pressure gaseous sample enters into the exhaust collecting system via the first port 521 and the sixth port 526 of the switch valve 52. The inert gas enters into the low-pressure environment through the third port 523 and the second port 522 of the switch valve 52, the first sampling chamber 520, the fifth port 525 and the fourth port 524 of the switch valve 52, the first port 531 and the sixth port 536 of the switch valve 53 so as to discharge the remainder gaseous sample in the first sampling chamber 520 to the low-pressure environment. The inert gas enters into the gaseous substance analyzer through the third port 533 and the second port 532 of the switch valve 53, the second sampling chamber 530, the fifth port 535 and the fourth port 534 of the switch valve 53 so as to discharge the low-pressure gaseous sample in the second sampling chamber 530 into the gaseous substance analyzer for further analysis.

[31] During a complete operating cycle, the sample collecting device switches from the first operating state to the second operating state and further to the third operating state.

After the gaseous substance analyzer completes an analysis cycle, the switch valve 52 is switched to the first communication state, the switch valve 53 is switched to the first

n communication state, and the cut off valve 55 is kept in the open state, such that the sample collecting device is switched from the third operating state to the first operating state to carry out a second cycle of the sampling analysis. At this stage, inert gas enters the low-pressure environment through the third port 523 and the fourth port 524 of the switch valve 52, the first port 531 and the second port 532 of the switch valve 53, the second sampling chamber 530, and the fifth port 535 and the sixth port 536 of the switch valve 53 so as to expel the remainder gaseous substance within the second sampling chamber 530 to the low-pressure environment. The inert gas enters into the gaseous substance analyzer through the third port 533 and the fourth port 534 of the switch valve 53 so as to expel the remained gaseous substance in the gaseous substance analyzer.

[32] Further, a check valve may be provided between the sixth port 536 of the switch valve 53 and the low-pressure environment to prevent the impurity gas in the low-pressure environment from flowing into the sixth port 536.

[33] Further, instead of switch valves, other valves and pipelines may be used and combined to make the sample collecting device switchable between said operating states, which are conceivable by those skilled in the art based on the teachings of the present invention. Therefore, the disclosure thereof is omitted.

[34] In another aspect, the present invention provides a method for collecting gaseous samples, the method comprising the steps of:

[35] collecting a high pressure gaseous sample with the first sampling chamber;

[36] keeping the first sampling chamber in fluid communication with a low-pressure environment via the second sampling chamber for a period of time, such that the high pressure gaseous sample in the first sampling chamber may expand naturally into the second sampling chamber until the pressure therein approaches to that of the low-pressure environment; and

[37] connecting an inert gas supply to an inlet of the gaseous substance analyzer via the first or the second sampling chamber, and introducing the gaseous sample in the first or the second sampling chamber into the gaseous substance analyzer with the inert gas.

[38] Further, in the first operating state, the second sampling chamber is also in fluid communication with both of the low-pressure environment and the inert gas supply so as

- S - to expel remainder substance in the second sampling chamber with the inert gas.

[39] Further, in the third operating state, the first sampling chamber is in fluid communication with both of the inert gas supply and the low-pressure environment.

[40] In another aspect, the present invention provides a cleansing unit for protecting the gaseous substance analyzer and preventing substances with relatively higher condensing point from entering into the gaseous substance analyzer and damaging it, the cleansing unit comprises a transition chamber, a condensing device and a heating device. In a condensing state, the transition chamber is in fluid communication with a source of the gaseous sample and the inlet of the gaseous substance analyzer respectively, the condensing device is in operating state and the heating device is shut down, so that substances having low condensing point is condensed in the transition chamber. In a heating state, one port of the transition chamber is in fluid communication with the inert gas supply and the other port thereof is in fluid communication with the low pressure environment, the condensing device is shut down and the heating device is operating such that substances condensed in the transition chamber are gasified and discharged to the low pressure environment with the inert gas.

[41] Further, referring to Fig.4, the condensing device comprises a condensing agent inlet 732, a condensing agent outlet 733 and a condensing chamber (not shown), wherein condensing agent is introduced via the condensing agent inlet 732, through the condensing chamber and discharged out from the condensing outlet 733 so as to carry away, heat and decrease the temperature in the transition chamber 731 of the cleansing unit 73, thus condensing some substance passing through the transition chamber 731.

[42] Further, the heating device is an electrical heating device 734.

[43] Further, the cleansing unit can be used together with the sample collecting device. The fourth port of the switch valve 52 is in fluid communication with the inlet of the transition chamber, and the outlet of the transition chamber is in fluid communication with the first port of the switch valve 53.

[44] Referring to Fig.2, when the sample collecting device is in the second operating state, the cleansing unit is in the condensing state. Therefore, condensing agent enters via the condensing agent inlet 732, passes through the condensing chamber and exits from the condensing agent outlet 733 so as to decrease the temperature in the transition

chamber and condense the passing substance having relatively higher condensing point from the first sampling chamber to the second sampling chamber in the transition chamber 731.

[45] When the sample collecting device is in either the first operating state or the third operating state, the cleansing unit is in the heating state. Therefore, remainder substance in the transition chamber 731 will be gasified and expelled to the low pressure environment with the inert gas.

[46] Of course, for all of the combinations above, the temperature in the transition chamber 731 of the cleansing unit is required to be decreased to a certain level before the gaseous sample in the first sampling chamber enter into the second sampling chamber.

[47] Further, the transition chamber 731 can be complicatedly designed, such as with a corrugated or labyrinthic configuration, to improve the contact between the substance and the transition chamber 731, thus facilitating the condensing more effectively.

[48] Further, said sample collecting device can be used in a parallel reactor system, and the gaseous sample from each reactor in the parallel reactor system can be introduced into said sample collecting device by turns through a selector valve.

[49] Further, said sample collecting device is suitable for any gaseous substance analyzer which is vulnerable to high pressure or high pressure impact, including but not limited to GC.

[50] Further, said parts of said sample collecting device can be made of materials including but not limited to stainless steel, copper, alloy etc. Stainless steel is preferred here.

BRIEF DESCRIPTION OF THE DRAWINGS

[51] Fig.l illustrates a first operating state of the sample collecting device according to the present invention.

[52] Fig.2 illustrates a second operating state of the sample collecting device according to the present invention.

[53] Fig.3 illustrates a third operating state of the sample collecting device according to

the present invention.

[54] Fig.4 illustrates the structure of a cleansing unit according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[55] In one embodiment, two switch valves and a cut off valve are used in combination, so said sample collecting device can be switched between said operating states by switching said two switch valves and cut off valve.

[56] Referring to Fig.l, the switch valve 52 is provided with a first port 521 , a second port 522, a third port 523, a fourth port 524, a fifth port 525 and a sixth port 526. The switch valve 52 has two communication states. In the first communication state, the first port 521 is in fluid communication with the second port 522, the third port 523 is in fluid communication with the fourth port 524, and the fifth port 525 is in fluid communication with the sixth port 526. Referring to Fig.2, in the second communication state, the first port 521 is in fluid communication with the sixth port 526, the second port 522 is in fluid communication with the third port 523, and the fourth port 524 is in fluid communication with the fifth port 525.

[57] A reactor vessel is in fluid communication with the first port 521 of the switch valve 52 and introduces the gaseous sample from the reactor vessel into the sample collecting device.

[58] Referring to Fig.l, the switch valve 53 is provided with a first port 531 , a second port 532, a third port 533, a fourth port 534, a fifth port 535 and a sixth port 536. The switch valve 53 has two communication states. In the first communication state, the first port 531 is in fluid communication with the second port 532, the third port 533 is in fluid communication with the fourth port 534, and the fifth port 535 is in fluid communication with the sixth port 536. Referring to Fig.3, in the second communication state, the first port 531 is in fluid communication with the sixth port 536, the second port 532 is in fluid communication with the third port 533, and the fourth port 534 is in fluid communication with the fifth port 535.

[59] The second port 522 of the switch valve 52 is in fluid communication with a port of the first sampling chamber 520; another port of the first sampling chamber 520 is in fluid communication with the fifth port 525 of the switch valve 52; the sixth port 526 of the

switch valve 52 is connected to a exhaust collecting system with the pressure of the effluent of said reactor vessel. The third port 523 of the switch valve 52 is in fluid communication with the inert gas supply, with a cut off valve 55 disposed in the pipeline therebetween; the fourth port 524 of the switch valve 52 is in fluid communication with an inlet of an transition chamber 731 of a cleansing unit 73.

[60] The first port 531 of the switch valve 53- is in fluid communication with the outlet of the transition chamber of the cleansing unit 73; the second port 532 of the switch valve 53 is in fluid communication with a port of a second sampling chamber 530; another port of the second sampling chamber 530 is in fluid communication with the fifth port 535 of the switch valve 53; the sixth port 536 of the switch valve 53 is in fluid communication with the atmosphere via a check valve for discharging exhaust gases; the third port 533 of the switch valve 53 is in fluid communication with the inert gas supply; the fourth port 534 of the switch valve 53 is in fluid communication with an inlet of a chromatographic apparatus (not shown).

[61] Referring to Fig.4, the cleansing unit 73 comprises: a transition chamber 731 ; condensing agent inlet 732 and condensing agent outlet 733 for inputting and outputting the condensing agent so as to cool down the gaseous substance before it enters into the chromatographic apparatus and condense the components which assume a liquid state at ambient temperature and pressure in the transition chamber 731, thereby protecting the apparatus from damaged by high temperatures or liquids; a heating device 734 for heating the transition chamber so as to gasify the components condensed therein, which assume a liquid state at ambient temperature and pressure. Afterwards, inert gas is introduced to discharge these components to the atmosphere.

[62] Referring to Fig.l, the switch valve 52 is operated in the first communication state, and the switch valve 53 is operated in the first communication state, such that the gaseous sample is output to the exhaust collecting system via the first port 521 , second port 522, first sampling chamber 520, fifth port 525 and sixth port 526 of the switch valve 52. After a period of time, the first sampling chamber 520 will be filled with the gaseous sample. A branch of the introduced inert gas travels through the third port 523 and fourth port 524 of the switch valve 52, the transition chamber 731 of the cleansing unit 73, the first port 531 and second port 532 of the switch valve 53, second sampling chamber 530, fifth port 535 and sixth port 536 and purges the second sampling chamber 530; another branch of the inert gas enters into the chromatographic apparatus via the

third port 533 and fourth port 534 of the switch valve 53 in order to purge the chromatographic apparatus.

[63] Referring to Fig.2, when the first sampling chamber 520 is filled with the gaseous sample, the cut off valve 55 is closed and the switch valve 52 is switched to the second communication state whereas the switch valve 53 is still operated in the first communication state. At this stage, the first sampling chamber 520 is in fluid communication with the second sampling chamber 530. Since the second sampling chamber 530 is under ambient pressure, the gas with high temperature and high pressure in the first sampling chamber 520 expands naturally, and enters into the second sampling chamber 530 after being cooled down in the transition chamber 731 of the cleansing unit

73, wherein a portion of the gaseous sample with relatively higher condensing point which passes through the transition chamber 731 is condensed in the transition chamber 731. The gaseous sample discharged from the reactor vessel enters into the exhaust collecting system via the first port 521 and sixth port 526 of the switch valve 52. Such a state is maintained for a certain period of time, such that the first sampling chamber 520 and the second sampling chamber 530 may reach or approach to the ambient pressure. Afterwards, the switch valve 53 is switched to the second communication state, and the switch valve 52 keeps working in the second communication state, and the cut off valve 55 is opened, as shown in Fig.3.

[64] Referring to Fig.3, the gaseous sample discharged from the reactor vessel enters into the exhaust collecting system via the first port 521 and the sixth port 526 of the switch valve 52. The transition chamber 731 is heated by the heating device 734, such that the substance condensed in the transition chamber 731 is gasified. A branch of introduced inert gas travels through the third port 523, second port 522, first sampling chamber 520, fifth port 525, fourth port 524 of the switch valve 52, the transition chamber 731 , and the first port 531 and sixth port 536 of the switch valve 53, such that the gasified substance in the transition chamber 731, which was previously condensed, is discharged out of the device and the transition chamber 731 is purged, after a period of time, when the substance condensed in said transition chamber 731 is gasified and expelled, switch the cleansing unit to the condensing state. Another branch of the inert gas travels through the third port 533 and the second port 532 of the switch valve 53, the second sampling chamber 530, the fifth port 535 and the fourth port 534, such that the gaseous sample in the second sampling chamber 530 is driven into the chromatographic

apparatus for analyzing.

[65] Fig.l to Fig.3 illustrates one complete sampling analysis cycle.