US3675466A - Sampling valve and system for the detection of predetermined compounds in air - Google Patents
Sampling valve and system for the detection of predetermined compounds in air Download PDFInfo
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- US3675466A US3675466A US65215A US3675466DA US3675466A US 3675466 A US3675466 A US 3675466A US 65215 A US65215 A US 65215A US 3675466D A US3675466D A US 3675466DA US 3675466 A US3675466 A US 3675466A
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- valve body
- aperture
- valve
- air
- housing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/16—Injection
- G01N30/20—Injection using a sampling valve
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/06—Preparation
- G01N30/12—Preparation by evaporation
- G01N2030/126—Preparation by evaporation evaporating sample
- G01N2030/128—Thermal desorption analysis
Definitions
- the valve includes a housing member having a plurality of apertures therein for enabling respective communication with at least a carrier medium, the ambient medium and the chromatographic column.
- a movable valve body member is mounted within the housing and is provided with a plurality of apertures for selective communication with predetennined ones of the housing member apertures.
- a platinum gauze member is retained within a predetermined one of the valve body member apertures and is selectively exposed to the ambient medium. The valve body member is then moved and the platinum gauze member is heated to desorb the predetermined compound in the presence of the carrier medium. such as helium, and the carrier medium together with the predete rmined compound are passed through the chromatographic column to enable detection of the presence of the predetermined compound.
- the present invention relates to a sampling valve and detector system and more particularly to a sampling valve for use with a chromatographic column or any other appropriate detection device for enabling the detection of at least one predetermined compound in an ambient medium, such as air.
- Plasma chromatographic detectors mass spectrometers, U. V. and I. R. spectrophotometers, fuel cells, gas chromatographs and various ionization detectors are among the instruments that have been developed in attempting to provide a highly sensitive, continuously operating, portable, automatic, highly selective, and versatile detection device.
- Injection of air samples into a gas chromatographic column or any other appropriate detection device is usually made with a syringe or by use of a gas sampling valve.
- these methods and the particular valves heretofore used have been found to be useful, they have several important disadvantages.
- air may interfere when injected with the organic vapors to be analyzed, and this interference is due to the high concentrations of nitrogen and oxygen in air as compared to the low concentrations of organic vapors that may be present.
- a sudden injection of or cc of air may cause serious interference in the flow rate of the carrier gas through the chromatographic column, the stability of which is very important. Furthermore, the maximum amount of IO cc of air that may be injected into the gas chromatograph is insufficient for sensitive determinations of the presence of organic compounds. Air samples of sizes of several liters must be injected to allow the detection of quantities of one ppb and below.
- an object of the present invention to provide a unique sampling valve for use with a chromatographic column or any other appropriate detection device for enabling the detection of at least one predetermined compound in an ambient medium, such as air.
- Another object is to provide a simply constructed, sturdy and inexpensive sampling valve for use with a chromatographic column system for enabling the detection of organic compounds in air.
- a further object of the invention is to provide a highly sensitive, selective and versatile apparatus for detecting the presence of organic compounds in a large sample of air.
- this invention provides apparatus that embraces all the advantages of similarly employed detection devices and w. none of the aforedescribed disadvantages.
- the invention utilizes a single, unique sampling valve, that together with a chromatographic system, provides a highly sensitive detection system which has a minimal response time and which is highly selective and versatile so that it can be readily used for the detection of a number of compounds.
- the device of this invention is also compact and portable and may be operated automaticslly.
- the sampling valve includes a housing member having a plurality of apertures therein for enabling respective communication with at least a carrier medium, an ambient medium, and a chromatographic column.
- a valve body member is movably mounted within the housing member and has a plurality of apertures therein for selective movement into communication with predetermined ones of the housing member apertures.
- the valve comprises means for adsorbing a predetermined compound from the ambient medium, and this adsorbing means, preferably platinum gauze, is in operative relationship with the valve body member for being retained within a predetermined one of the valve body member apertures at least during selective exposure to the ambient medium.
- Means are also provided in operative relationship for selectively heating the adsorber means to desorb any compounds previously adsorbed by the platinum gauze and the desorbed compounds are carried into the through the chromatographic column by a carrier gas, such as helium.
- FIG. 1 is a sectional view of one embodiment of the sampling valve of this invention in a first position which respect to a chromatographic column;
- FIG. 2 is a sectional view of the embodiment illustrated in FIG. 1 showing movement of an adsorber ball into the sampling valve;
- FIG. 3 is a sectional view of the arrangement illustrated in FIG. I wherein the sampling valve is in a second position;
- FIG. 4 is a sectional view of the embodiment shown in FIG. 1 representing return of the adsorbcr ball to a position adjacent the chromatographic column;
- FIG. 5 is a detailed view, partly in section, of another embodiment of the sampling valve of this invention in a first position
- FIG. 6 is a view, partly in section, of the valve illustrated in FIG. 5 in a second position
- FIG. 7 is a view, partly in section, of the sampling valve embodiment shown in FIG. 5 and wherein the valve is in a third position;
- FIG. 8 is a section of the sampling valve taken on the line 88 of FIG. 7 looking in the direction of the arrows;
- FIG. 9 is a view, partly in section, of still another embodiment of the sampling valve of this invention wherein the valve is in a first position
- FIG. 10 is a view, partly in section, of the valve shown in FIG. 9 and wherein the valve is in a second position;
- FIG. 11 is a view, partly in section, of the valve shown in FIG. 9 and wherein the valve is in a third position;
- FIG. 12 is a partial section of the sampling valve taken on the line 12-12 of FIG. 9 looking in the direction of the arrows;
- FIG. 13 is a diagrammatic view of one embodiment of a detector system of this invention.
- FIG. 14 is a diagrammatic view of another embodiment of a detector system in accordance with this invention.
- the detector system of this invention utilizes a valve body member which is preferably made of polytetrafiuoroethylene and which is free to rotate in a housing member preferably made of stainless steel. Other suitable materials can be used for the valve body member and for the housing member.
- the housing member is connected to a gas chromatographic column and is designed in such a way that at one position ambient atmospheric air flows through the valve while at a second position the valve is open to the chromatographic column and closed to the ambient air.
- a small ball of platinum gauze which may be coated with the appropriate liquid phase is used for the adsorption of the compounds to be detected.
- organic compounds for example, will be adsorbed by the ball while other gases will pass through the ball without being adsorbed thereby.
- Selective adsorption is achieved through the use of the proper phase as is well known in the art.
- the platinum ball is heated and all the compounds previously adsorbed on the ball are immediately desorbed and are carried into the chromatographic column by an inert carrier gas, such as nelium, for analysis and for indication of the presence or absence of the compounds.
- FIGS. 1-4 one embodiment of the sampling valve of this invention in various positions of operation.
- a housing member having a plurality of apertures 22, 24, 26, and 28 therein is mounted with aperture 26 in communicating relationship with a chromatographic column via a tubular member 32.
- Apertures 22 and 24 are in communicating relationship with an ambient medium, such as the atmosphere, while aperture 28 is in communicating relationship with a supply of carrier gas, such as helium.
- valve body member 34 is movably mounted within housing member 20 to be rotated about a centrally located axis.
- Valve body member 34 has a plurality of apertures 36 and 38 therein which are in communication with each other in a substantially V-shaped configuration.
- means for adsorbing a predetermined compound are provided in operative relationship with valve body member 34 for being retained within a predetermined one of the valve body member apertures at least during selective exposure to the ambient medium or atmosphere.
- the adsorbing means is a platinum gauze ball 40 which is normally held within a magnetizable iron holder 42 located within tubular member 32.
- electromagnetic means are provided in operative relationship for selectively moving holder 42 within tubular member 32 to cause the adsorbing ball 40 to be impelled into a first one 38 of the valve body member apertures.
- the electromagnetic means is an electromagnet 44 which surrounds tubular member 32.
- the invention also provides means in operative relationship for selectively heating the adsorber means 40.
- the heating means is an oven 46, a portion of which is illustrated in FIGS. 1-4 and which is shown in its entirety in FIGS. 13 and 14.
- the oven 46 encloses electromagnet 44 and at least a portion of tubular member 32.
- the small platinum gauze ball 40 is initially situated in the magnetizable (iron) gauze holder 42.
- the holder is at the lower end of tubular member 32 and is surrounded by electromagnet 44.
- the electromagnet and tube 32 are situated within oven 46 so that the temperature of chromatographic column 30 and of the column inlet is controlled.
- the valve body member 34 is rotated to a first position (the sampling position) whereby a first one of the valve body member apertures 36 is sealed at one end by hous ing member 20 while a second one of the valve body member apertures 38 is in communication with chromatographic column 30 and with tubular member 32. This position is illustrated in FIG. I.
- a plurality of voltage pulses are then applied to electromagnet 44 via two connections 50 and 51 so that iron gauze holder 42 together with platinum gauze sphere 40 are caused to jump upwardly.
- the ball 40 is thrown into valve body member 34 and into the aperture 36 where it remains.
- Tubular member 32 and the entire assembly illustrated in FIGS. 1-4 are preferably located at a relatively alight angle with respect to the vertical so that platinum gauze ball 40 is readily retained within aperture 36 (FIG. 2).
- Valve body member 34 is then rotated clockwise until apertures 36 and 38 are in communication with apertures 24 and 22, respectively. See FIG. 3. It air is then passed through the apertures and over the platinum gauze ball, certain compounds, it present in the atmosphere, will be adsorbed by the ball. Thus, air is conventionally passed through the apertures by means of a pump 124 (FIGS. 13 and 14) which forces air through apertures 22, 38, 36, and 24 so that platinum gauze ball 40 adsorbs the compound or compounds which may be in the atmosphere and the detection of which is desired.
- a pump 124 FIGS. 13 and 14
- valve body member 34 After the atmosphere has been passed over platinum gauze ball 40 with valve body member 34 in the second position (FIG. 3) for the desired length of time, valve body member 34 is rotated back to its first or sampling position (FIG. 4) where the apertures 36 and 38 as well as ball 40 are sealed from the atmosphere and so that ball 40 will drop down to its original position within gauze holder 42. Because the platinum gauze ball 40 is now located within the oven 46, any compounds which may have been adsorbed by the gauze ball are immediately desorbed and are carried into chromatographic column 30 by a carrier gas, such as helium entering through aperture 28.
- a carrier gas such as helium entering through aperture 28.
- FIGS. 5-8 illustrate another embodiment of the sampling valve of this invention.
- a housing member 20' is provided with a plurality of apertures therein for enabling respective communication with at least a carrier medium, an ambient medium, such as the atmosphere, and a chromatographic column.
- housing member 20' includes apertures 52 and 54, which are in communication with a carrier gas. such as helium. Additional apertures 56 and 58 are provided in communication with the ambient medium, such as air.
- a purge aperture 60 is also provided in communication with the ambient medium and an aperture 62 is provided in communication with chromatographic column 30.
- Valve body member 34 is movably mounted within housing member 20' and includes a plurality of apertures therein for selective movement into communication with predetermined ones of the housing member apertures.
- valve body member 34' includes apertures 64 and 66 which are in different planes with respect to one another and which may be perpendicular with respect to one another. Although apertures 64 and 66 are shown and described as being perpendicular with respect to one another, it should be understood that they need not be perpendicular and that they can be oriented at any number of angles with respect to one another as long as the apertures in the housing member 20 are appropriately located.
- housing member 20' includes two keyways 70 and 72 in communication with apertures 54 and 62 for enabling selective communication of each of the valve body member apertures 64 and 66 with housing member apertures 54 and 62 whereby flow of the carrier medium through the chromatographic column is maintained substantially constant during operation of the valve. This feature will be explained in more detail infra where the operation of this valve embodiment is set forth.
- platinum gauze ball 40' is captured within valve body member aperture 64.
- a storage capacitor 74 for example, or any other suitable electrical energy storage means, is electrically coupled to platinum gauze 40' via leads 76 and 78, and a switch 80 is located in circuit with capacitor '74 together with an electrical source 82 whereby capacitor 74 is selectively charged by energy source 82 and discharged by closing of the switch 80.
- Capacitor 74 through leads 76 and 78 is utilized to heat the gauze since the gauze is not dropped into the oven, as was the case with the embodiment illustrated in FIGS. l4.
- gauze 40' need not be spherical in shape but may be of a fiat configuration, for example.
- valve body member 34 is rotated to a first position as shown in FIG. 5, valve body member aperture 64 is in com munication with housing apertures 56 and 58 and with the atmosphere or ambient medium.
- second valve body member aperture 66 is in communication with keyways 70 and 72 and with housing apertures 54 and 62.
- the carrier gas such as helium
- the carrier gas passes through tube 90, aperture 54, aperture 66 and aperture 62 so as to pass into and through chromatographic column 30.
- air from the ambient medium is drawn through apertures 56, 64, and 58 by means of a pump (124 in FIGS. 13 and 14) so that air passes through platinum gauze 40' whereby certain compounds that are present in the atmosphere are adsorbed by the gauze.
- an important feature of this embodiment of the sampling valve is that it pro vides a substantially continuous and steady carrier gas flow rate through the chromatographic column via aperture 66 even when the platinum gauze 40' is being subjected to the atmosphere.
- valve body member 34' After gauze 40' has been exposed to the air for the desired length of time valve body member 34' is rotated clockwise to the position shown in FIG. 7. Before reaching that position, however, valve body member 34' passes through a second position (FIG. 6) whereby first valve body aperture 64 containing the gauze ball 40' is placed in communication with the carrier medium via apertures 52 and 60 whereby first aperture 64 is flushed of any residual air from the atmosphere by means of the carrier gas. At this position second aperture 66 is sealed by housing member By flushing the apertures the accuracy of the results is markedly enhanced since all air is expelled from the system prior to the desorbing step.
- Valve body member 34' is then rotated to the third position (FIG. 7) and first aperture 64 is placed in communicating relationship with the carrier medium via aperture 54 and with the chromatographic column via aperture 62.
- the second valve body member aperture 66 is offset and is not in communication with housing apertures 56 and 58 and is therefore sealed by housing member 20' when the valve body member is in the third position.
- a housing member 2 which has a plurality of apertures therein for enabling respective communication with at least a carrier medium, an ambient medium such as air, and a chromatographic column.
- the housing member 20" includes apertures 92 and 94, which are in communicating relationship with the ambient medium or atmosphere.
- housing member 20" includes a purge outlet or aperture 96 which is also in communicating relationship with the atmosphere.
- An aperture 26 is in communicating relationship with chromatographic column 30, and aperture 28 is provided in communicating relationship with the carrier medium or gas, such as helium.
- Valve body member 34" of this embodiment has first and second apertures I02 and 104, respectively, which are in a substantially V-shaped configuration with one another.
- the second aperture 104 is closed at one end I06 thereof, and a purge aperture 108 is provided in communicating relationship with the V-shaped configuration.
- a support member 110 is located across purging aperture 108 and ad jacent to apertures 102 and 104 for holding the platinum gauze ball when valve body member 34" is in a third position (FIG. I I
- valve body member 34" of the embodirnent illustrated in FIGS. 9-12 has a tapered cross section for enabling a better sealing fit within housing member 20". This configuration also represents a preferred arrangement for the previously described embodiments.
- Body member 34" is provided with an extension 112 which has a member I14 fitted thereover and a knob I16 attached thereto for enabling manual rotation of valve body member 34" about the axis 1 18.
- the small ball of platinum gauze is initially located in the cylindrical iron holder 42.
- the holder is located at the lower end of tubular member 32 which is surrounded by electromagnet 44.
- the electromagnet and the tubular member are both located in an oven 46 in which the temperature is controlled by a temperature controller 12] (FIGS. 13 and 14).
- the valve is first positioned as illustrated in FIG. 9.
- the first position die first one of the apertures I02 is in communication with tubular member 32 and with chromatographic column 30 while purge aperture I08 is sealed at one end by housing member 2
- a plurality of voltage pulses are applied to electromagnet 44 via leads 50 and 51, and iron gauze holder 42 is caused to jump upwardly so as to throw the platinum gauze ball 40 into the valve body member 34" and into closed aperture I04 where it remains.
- the entire assembly as illustrated in FIGS. 9-12, may be located at an angle with respect to the vertical so that the gauze ball is readily retained within the closed aperture 104.
- Valve body member 34" is then rotated clockwise to a second position, as illustrated in FIG. 10, to enable purge aperture 108 to be in communication with purge outlet 96.
- first aperture 102 in the V-shaped configuration is still in partial communication with the carrier medium and aperture 28 so that the carrier gas passes through aperture 102 and through purge aperture 108 to purge the valve body member of any residual gases prior to sampling which might remain therein.
- Valve body member 34" is then rotated to a third position (FIG. 11 so that the first aperture 102 is in communication with the atmosphere and with housing aperture 92 and so that purge aperture 108 is in communication with the atmosphere and with housing aperture 94.
- the platinum gauze ball 40 falls onto and is supported by support member 110.
- valve body member 34" With valve body member 34" in the third position (FIG. 11) the ambient medium, such as air, is caused by means of a pump I24 (FIGS. 13 and 14) to pass through apertures 92. I02, I08, and 94. If certain compounds are present in the atmosphere it will be adsorbed on the gauze ball 40.
- a pump I24 FIGS. 13 and 14
- valve body member 34" is then rotated in a counterclockwise direction from its position as illustrated in FIG. 11, and as member 34" passes through the second position (FIG. 10) the carrier gas again purges apertures 102, 104, and 108 of air to avoid contamination of chromatographic column 30.
- Member 34" continues to rotate in the counterclockwise direction until the first position (FIG. 9) is reached.
- the platinum gauze ball then drops from its position on support member 110 down and through tubular member 32 until it comes to rest within gauze holder 42. Any compounds which may have been adsorbed by the platinum ball are desorbed immediately within the heated environment of oven 46 and are carried into chromatographic column 30 by the carrier gas which passes into tubular member 32 via aperture 28.
- sampling apparatus of this invention and the sampling valve can be operated completely automatically by means of systems as illustrated in FIGS. 13 and 14.
- the embodiment of FIG. 13 includes an automatic control circuit 120, which may be a conventional timing circuit and which acts as the master control for operation of the entire system.
- a motor 122 is activated to rotate the sampling valve of this invention to the sampling position.
- the platinum gauze is already located within the valve or a series of voltage pulses applied to the electromagnet 44 cause the iron gauze holder to jump upwardly so that the ball is thrown into the valve body member where it is trapped.
- Motor 122 is again activated by automatic control circuitry 120 and rotates until stopped by a controlling microswitch (not shown) so that the platinum ball is exposed to the atmosphere and air is passed through the ball by means offan 124.
- valve rotates backwardly until it is stopped by another controlling microswitch (not shown) at such an angle that the ball drops down to its initial position, or in the case of the embodiment of FIGS. 5-8, the ball is placed in communication with the carrier gas and with the chromatographic column.
- the ball is then heated so that any compounds which may have been adsorbed by the platinum gauze are now desorbed immediately and carried into the chromatographic column by the carrier gas, which enters from aperture 28 and which is supplied by carrier gas supply 124.
- recorder 126 is activated by automatic control circuitry 120 for a specified time, e.g. l-3 minutes.
- the compounds and carrier gas advance along the separation column and the flow rate of the carrier gas through the column remains constant. Both temperature and flow rate are chosen in each case in accordance with the characteristics of the specific compound to be detected. Any compound will reach the end of the chromatographic column at a particular fixed time, depending upon the temperature and flow rate and on the column packing, and this time is specific to each compound.
- a conventional ionization detector (not shown). This detector responds to organic compounds by generating a current which is displayed on recorder 126 after being amplified by an electrometer amplifier 140.
- FIG. 14 Another arrangement for detecting the presence of compounds in air is shown in FIG. 14. This particular apparatus is illustrated in combination with the sampling valve of FIGS. 1-4 or of FIGS. 9-12; however, the sampling valve embodimerit illustrated in FIGS. 5-8 could be readily utilized with this system.
- the ball of platinum gauze 40 is thrown upwardly into the valve and is trapped there as previously explained. Movement of the ball is observed by a photoelectric cell 130, which is located under the valve.
- the tubular member 32 in this embodiment has two windows 132 which allow a beam of light from a small bulb 134 to reach the photoelectric cell 130. A signal is generated each time the ball, moving upwardly, intercepts the beam, and a different signal results when the ball moves downwardly.
- valve Alter the ball is received by the valve, motor 122 is activated to rotate the valve until it is stopped by a controlling microswitch (not shown). The platinum ball is then exposed to the atmosphere and air containing the sample is passed through the ball by means of the pump 124. During this operation the carrier gas (helium) enters column 30 through the aperture 28 at the lower end of the valve so that the flow of carrier gas through the column is not afiected by rotation of the valve. This is true for the valve embodiments of FIGS. 1-4 and of FIGS. 9-12 while the helium flow is only slightly interrupted as the valve body member of the embodiment shown in FIGS.
- carrier gas helium
- the column may be made of polytetrafluoroethylene tubing 30 cm long and l A mm I. D. and is packed with 15 percent D.E.G.S. on 60-80 chromosorb W.A.W.
- the flow rate of the carrier gas through the column 30 is constant and both the temperature and flow rate are chosen in each case to identify the specific compound sought to be detected. Any compound will reach the end of the column 30 at a particular fixed time, depending upon the temperature and flow rate and in other cases the column packing. This time is characteristic for each compound.
- a conventional ionization detector 138 responds to organic compounds by generating a current which is displayed on recorder 126 after being amplified by electrometer Thus, if a compound is present the recorder will indicate its presence to the operator.
- An alarm system is connected in parallel to the recorder and is activated when a peak signal arrives in order to indicate when a specific compound is present in the atmosphere.
- the present invention provides for a unique sampling valve and for unique apparatus for detecting the presence of compounds in the atmosphere wherein the device is highly sensitive, has a short time response, is portable, automatic, highly selective, and versatile and wherein a gas chromatograph or any other suitable detection device is utilized to enable the detection of extremely low concentrations of organic vapors in the atmosphere.
- a sampling valve for concentrating at least one predetemiined compound in an ambient medium comprising:
- a housing having a first aperture having an inlet and outlet end, both communicating with the ambient medium and a second aperture communicating with the detection device;
- valve body movably mounted within the housing and having a V-shaped aperture therein for selective communication with the housing apertures
- valve body means for sequentially moving the valve body between a first position where the valve body aperture communicates with the first housing aperture to expose the adsorbing means located in the valve body aperture to the ambient medium and to a second position where the valve body aperture communicates with the second housing aperture;
- a tubular member in communicating relationship between the second housing aperture and the detection device; said adsorbing means passing into the tubular member when the valve body aperture is moved to the second position from the first position;
- valve body aperture is sealed to the ambient medium when in the second position.
- a holder located within the tubular member for holding the adsorbing means
- the adsorbing means include a substantially spherical mass of adsorptive material.
- heating means in cludes an oven surrounding the tubular member for selectively heating the adsorbing means in its holder.
- the device of claim 8. including means for purging the valve body aperture with the carrier medium as the valve body aperture moves between said first and second positions.
- the purging means includes a purge aperture in the housing that communicates with the valve body aperture and permits the carrier medium to pass through the valve body aperture.
- a device for the detection of a predetermined compound in air comprising:
- sampling valve for concentrating the compound from the air and transferring the compound from the air in an air-free atmosphere to the gas column, said sampling valve comprising:
- valve housing having an air inlet and outlet, and a discharge outlet communicating with the gas chrmatographic column
- valve body movably mounted within the valve housing and having an aperture therein for selective communication with the housing: air inlet and outlet when the valve body is in a first position and with the discharge outlet when the valve body is in a second position, iii. means for moving said valve between said first and second positions, and iv. adsorber means located within the valve body aperture for adsorbing and concentrau'ng the compound from d. means for passing air through the valve housing and the valve body aperture in said first position to expose the adsorber means to the air;
- purge means communicating the valve body aperture with a supply of air-free carrier gas as the valve body passes through a position intermediate said first and second positions to purge the valve body aperture and the adsorber means of residual air;
- heater means for selectively heating the adsorber means after it has adsorbed the compound and been purged of residual air to desorb the compound from the adsorber means;
- heating means include:
- adsorbing means include a piece of platinum gauze or any other adsorptive material of any metal or chemical fixidly mounted within the valve body aperture.
- the purge means comprises a carrier gas inlet land an outlet for the carrier gas in the valve housing, said inlet and outlet communicating with the valve body aperture as it passes through said intermediate position.
- the device of claim 14 including a passage in the valve body communicating with the carrier gas inlet and the discharge outlet when the valve body is in said first position, said carrier gas inlet also communicating with the valve body aperture when the valve body is in said second position to transmit the desorbed compound to the gas column. thereby maintaining a substantially constant flow of carrier gas to the column.
- the carrier gas inlet comprises a first aperture in the housing communicating with the valve body aperture when said valve body is at said intermediate position and a second aperture in the housing communicating with the valve body aperture when the valve body is at said second position and with the valve body passage when the valve body is at said first position; said first and second apertures communicating with a common supply of carrier gas.
- a device for the detection of a predetermined compound in air comprising:
- a sampling valve for concentrating the predetermined compound from the air comprising a valve housing having an air inlet and outlet and a discharge outlet communicating with the gas chromatographic column;
- valve body movably mounted within the valve housing and having a V-shaped aperture therein for selective communication with the housings air inlet and outlet when the valve body is in a second position and with the discharge outlet when the valve body is in a second posinon;
- adsorber means located in the V-shaped aperture when the valve body is in the first position for adsorbing and concentrating said predetermined compound from the air;
- h. means for selectively heating the adsorber means to desorb the compound from the adsorber means when the adsorber means is located in the tubular member;
- Claim 18, column 11, subparagraph d, line 4, second position" should be -first position.
Abstract
Description
Claims (20)
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US6521570A | 1970-08-19 | 1970-08-19 |
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US65215A Expired - Lifetime US3675466A (en) | 1970-08-19 | 1970-08-19 | Sampling valve and system for the detection of predetermined compounds in air |
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US3819330A (en) * | 1972-02-07 | 1974-06-25 | Itt | Fluid monitoring system and fluid sampling method and apparatus for use therewith |
US4128008A (en) * | 1977-05-04 | 1978-12-05 | Xonics, Inc. | Concentration valve for a gas detecting apparatus, or the like |
US4399688A (en) * | 1981-05-18 | 1983-08-23 | Phillips Phillips Petroleum | Air pollution detection |
US4403520A (en) * | 1980-01-02 | 1983-09-13 | Carlo Erba Strumentazione S.P.A. | Control valve for a direct on-column injector and injection method |
US4454749A (en) * | 1980-09-26 | 1984-06-19 | Prolabo | Device for column chromatography apparatus |
US4967590A (en) * | 1989-09-18 | 1990-11-06 | Und-Sem Foundation | Supercritical fluid chromatography injector and the method for using the same |
US5435169A (en) * | 1993-06-14 | 1995-07-25 | New Jersey Institute Of Technology | Continuous monitoring of organic pollutants |
US6455003B1 (en) | 1999-11-17 | 2002-09-24 | Femtometrics, Inc. | Preconcentrator for chemical detection |
US6477905B1 (en) | 1993-06-14 | 2002-11-12 | New Jersey Institute Of Technology | Apparatus and instrumentation for measurement of TOC, NMOC and VOCs |
US6656738B1 (en) * | 1999-11-17 | 2003-12-02 | Bae Systems Integrated Defense Solutions Inc. | Internal heater for preconcentrator |
US20080028827A1 (en) * | 2006-08-03 | 2008-02-07 | Andrews William H | Clandestine grave detector |
US20090131643A1 (en) * | 2006-04-14 | 2009-05-21 | Zheng Ni | Rapid metal organic framework molecule synthesis method |
US8123841B2 (en) | 2008-01-16 | 2012-02-28 | The Board Of Trustees Of The University Of Illinois | Column design for micro gas chromatograph |
US8123834B2 (en) | 2005-10-06 | 2012-02-28 | The Board Of Trustees Of The University Of Illinois | High gain selective metal organic framework preconcentrators |
US8269029B2 (en) | 2008-04-08 | 2012-09-18 | The Board Of Trustees Of The University Of Illinois | Water repellent metal-organic frameworks, process for making and uses regarding same |
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US3819330A (en) * | 1972-02-07 | 1974-06-25 | Itt | Fluid monitoring system and fluid sampling method and apparatus for use therewith |
US4128008A (en) * | 1977-05-04 | 1978-12-05 | Xonics, Inc. | Concentration valve for a gas detecting apparatus, or the like |
US4403520A (en) * | 1980-01-02 | 1983-09-13 | Carlo Erba Strumentazione S.P.A. | Control valve for a direct on-column injector and injection method |
US4454749A (en) * | 1980-09-26 | 1984-06-19 | Prolabo | Device for column chromatography apparatus |
US4399688A (en) * | 1981-05-18 | 1983-08-23 | Phillips Phillips Petroleum | Air pollution detection |
US4967590A (en) * | 1989-09-18 | 1990-11-06 | Und-Sem Foundation | Supercritical fluid chromatography injector and the method for using the same |
US6477905B1 (en) | 1993-06-14 | 2002-11-12 | New Jersey Institute Of Technology | Apparatus and instrumentation for measurement of TOC, NMOC and VOCs |
US5435169A (en) * | 1993-06-14 | 1995-07-25 | New Jersey Institute Of Technology | Continuous monitoring of organic pollutants |
US6455003B1 (en) | 1999-11-17 | 2002-09-24 | Femtometrics, Inc. | Preconcentrator for chemical detection |
US6656738B1 (en) * | 1999-11-17 | 2003-12-02 | Bae Systems Integrated Defense Solutions Inc. | Internal heater for preconcentrator |
US8123834B2 (en) | 2005-10-06 | 2012-02-28 | The Board Of Trustees Of The University Of Illinois | High gain selective metal organic framework preconcentrators |
US20090131643A1 (en) * | 2006-04-14 | 2009-05-21 | Zheng Ni | Rapid metal organic framework molecule synthesis method |
US7880026B2 (en) | 2006-04-14 | 2011-02-01 | The Board Of Trustees Of The University Of Illinois | MOF synthesis method |
US20080028827A1 (en) * | 2006-08-03 | 2008-02-07 | Andrews William H | Clandestine grave detector |
US8074490B2 (en) | 2006-08-03 | 2011-12-13 | Ut-Battelle Llc | Clandestine grave detector |
US8123841B2 (en) | 2008-01-16 | 2012-02-28 | The Board Of Trustees Of The University Of Illinois | Column design for micro gas chromatograph |
US8152908B2 (en) | 2008-01-16 | 2012-04-10 | The Board Of Trustees Of The University Of Illinois | Micromachined gas chromatography columns for fast separation of Organophosphonate and Organosulfur compounds and methods for deactivating same |
US8269029B2 (en) | 2008-04-08 | 2012-09-18 | The Board Of Trustees Of The University Of Illinois | Water repellent metal-organic frameworks, process for making and uses regarding same |
US8726719B2 (en) | 2010-07-31 | 2014-05-20 | Ut-Battelle, Llc | Light-weight analyzer for odor recognition |
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