Apparatus and methods for separating, concentrating, detecting, and measuring trace gases

Claim 5

A method in accordance with claim 2, further comprising moving said body of gas as a stream during the segregating of said component.

Claim 6

A method in accordance with claim 3, wherein the drift field is transverse to the stream movement.

Claim 9

A method in accordance with claim 5, wherein a group of said product ions is selectively gated to a first region and then a portion of said group is selectively gated from said first region to said detecting means.

Claim 10

A method in accordance with claim 5, wherein said product ions are detected by growing aerosol droplets thereon and detecting the droplets optically.

Claim 11

A method in accordance with claim 5, wherein said gaseous substance is a trace vapor in an inert gas effluent of a gas chromatograph and wherein said reactant ions are formed from the molecules of a separate reactant gas.

Claim 12

A method in accordance with claim 5, wherein said pressure is substantially atmospheric.

Claim 13

A method in accordance with claim 5, wherein the reactant ions are formed substantially continually during the performance of the recited steps.

Claim 14

A method in accordance with claim 10, wherein the drift field is applied substantially continuously and unidirectionally during the other recited steps.

Claim 15

Apparatus for separating components from a gas, comprising an envelope having means for introducing said gas therein, means for producing rEactant ions at a first region of said envelope for reaction with the molecules of said components to form product ions, means for applying a drift field to said ions for causing said ions to drift from said first region toward a second region of said envelope, ion gate means between said regions, and means for opening said gate means for a predetermined interval during the application of said drift field to pass ions of predetermined drift velocity to said second region, and means for maintaining the pressure in said envelope such that the length of the gas collision mean free path is very much less than the dimensions of said envelope.

Claim 16

Apparatus for separating components from a gas, comprising an envelope having means for introducing said gas therein, means for producing rEactant ions at a first region of said envelope for reaction with the molecules of said components to form product ions, means for applying a drift field to said ions for causing said ions to drift from said first region toward a second region of said envelope, ion gate means between said regions, and means for opening said gate means for a predetermined interval during the application of said drift field to pass ions of predetermined drift velocity to said second region, and means for maintaining the pressure in said envelope such that the length of the gas collision mean free path is very much less than the dimensions of said envelope.

Claim 17

The apparatus of claim 12, said gate means comprising a grid having two interdigitated substantially coplanar sets of grid elements and having means for normally maintaining adjacent elements at equal and opposite potentials with respect to a reference potential, and said means for opening said gate means comprising means for placing all of said grid elements substantially at said reference potential.

Claim 18

The apparatus of claim 12, further comprising means for varying the time of opening of said gate means.

Claim 19

The apparatus of claim 13, further comprising means for producing an output in response to the ions at said second region.

Claim 20

The apparatus of claim 12, said gate means comprising a pair of shutter grids arranged seriatim in the path of said ions.

Claim 21

Apparatus for detecting the presence of a substance in a gas, comprising an envelope having means for introducing said gas therein, means for providing reactant ions at a first region of said envelope to form product ions by reaction with said substance at said first region, means for applying a drift field to said ions for causing said ions to drift from said first region toward a second region of said envelope, first and second ion gates arrange serially between said first and said second regions, means for opening the first ion gate at a predetermined time to pass a group of said product ions toward said second ion gate, and means for opening said second ion gate at a predetermined time after the opening of said first ion gate to pass a portion of the ions passed by said first ion gate, means for maintaining the pressure in said envelope at a level such that the length of the gas collision mean free path is very much less than the dimensions of said envelope, and means for detecting at least some of the ions passed by said second ion gate in a manner so as to distinguish them.

Claim 22

Apparatus for detecting the presence of a substance in a gas, comprising an envelope having means for introducing said gas therein, means for providing reactant ions at a first region of said envelope to form product ions by reaction with said substance at said first region, means for applying a drift field to said ions for causing said ions to drift from said first region toward a second region of said envelope, first and second ion gates arrange serially between said first and said second regions, means for opening the first ion gate at a predetermined time to pass a group of said product ions toward said second ion gate, and means for opening said second ion gate at a predetermined time after the opening of said first ion gate to pass a portion of the ions passed by said first ion gate, means for maintaining the pressure in said envelope at a level such that the length of the gas collision mean free path is very much less than the dimensions of said envelope, and means for detecting at least some of the ions passed by said second ion gate in a manner so as to distinguish them.

Claim 23

The apparatus of claim 17, wherein said detecting means comprises an electrometer.

Claim 24

The apparatus of claim 17, wherein said detecting means comprises means for producing aerosol particles from the ions passed thereto and means for optically detecting said aerosol particles.

Claim 25

The apparatus of claim 17, further comprising means for removing said gas from said envelope continuously as it is introduced into said envelope.

Claim 26

Apparatus in accordance with claim 17, each of said ion gates comprising a grid having two interdigitated substantially coplanar sets of grid elements and having means for normally maintaining adjacent elements at equal and opposite potentials with respect to a reference potential, and said means for opening said gates comprising means for placing all of the elements of a grid substantially at said reference potential.

Claim 27

Apparatus in accordance with claim 17, wherein said means for providing reactant ions comprises a continuous ionizing source.

Claim 28

Apparatus in accordance with claim 17, wherein said means for applying said drift field comprises means providing a unidirectional drift field continuously.

Claim 29

Apparatus in accordance with claim 17, said means for applying a drift field comprising a pair of electrodes at said first and second regions, respectively, and means for providing a DC potential difference between said electrodes continuously, said means for providing reactant ions comprising a continuous ionizing source associatEd with the electrode at said first region, each of said ion gates comprising a grid having two interdigitated substantially coplanar sets of grid elements and having means for normally maintaining adjacent elements at equal and opposite potentials with respect to a reference potential, and said means for opening said gates comprising means for placing all of the elements of a grid substantially at said reference potential.

Claim 30

Apparatus for detecting trace gas components in an inert gas flowing in the conduit, which comprises an envelope, means for introducing said inert gas and said trace gas into said envelope, means for introducing a reactant gas into said envelope, means at a first region of said envelope for producing reactant ions from the molecules of said reactant gas to form product ions from said trace gas as the result of reaction of the molecules of said trace gas with said reactant ions, means for applying a drift field to said ions for causing said ions to drift from said first region of said envelope toward a second region of said envelope, ion gate means between said regions, means for operating said gate means at a predetermined time to pass a portion of said product ions to said second region, means for detecting at least some of the product ions passed to said second region so as to distinguish them, and means for maintaining the pressure in said envelope at a level such that the length of the gas collision mean free path is very much less than the dimensions of said envelope.

Claim 31

Apparatus for detecting trace gas components in an inert gas flowing in the conduit, which comprises an envelope, means for introducing said inert gas and said trace gas into said envelope, means for introducing a reactant gas into said envelope, means at a first region of said envelope for producing reactant ions from the molecules of said reactant gas to form product ions from said trace gas as the result of reaction of the molecules of said trace gas with said reactant ions, means for applying a drift field to said ions for causing said ions to drift from said first region of said envelope toward a second region of said envelope, ion gate means between said regions, means for operating said gate means at a predetermined time to pass a portion of said product ions to said second region, means for detecting at least some of the product ions passed to said second region so as to distinguish them, and means for maintaining the pressure in said envelope at a level such that the length of the gas collision mean free path is very much less than the dimensions of said envelope.

Claim 32

Apparatus in accordance with claim 25, said means for introducing said inert gas and said trace gas comprising means for feeding those gases to said envelope at the same rate of flow as the rate of flow of those gases in the conduit.

Claim 37

A method in accordance with claim 28, wherein the time of the last-mentioned gating relative to the first is varied for plural cycles of operation.

Claim 38

A method in accordance with claim 28, wherein said pressure is substantially atmospheric.

Claim 39

A method in accordance with claim 28, wherein the ions are formed substantially continuously during the performance of the other recited steps.

Claim 40

A method in accordance with claim 28, wherein the drift field is applied substantially continuously and unidirectionally during the other recited steps.

Claim 41

Apparatus for concentrating a component of a gas, comprising a duct, means for moving a stream of said gas through said duct, an electrode of one polarity having associated therewith a source of reactant ioNs at a first region of said duct for forming product ions from the molecules of said component, means including an electrode of opposite polarity at a second region of said duct for attracting and neutralizing said product ions, a passage adjacent to the last-mentioned electrode and separated from said stream for withdrawing molecules of said component to a region separated from said stream and at which the concentration of said component is greater than in said stream, and means for maintaining the pressure in said duct at a level such that the length of the mean free path of said ions is very much less than the dimensions of said duct.

Claim 42

Apparatus for concentrating a component of a gas, comprising a duct, means for moving a stream of said gas through said duct, an electrode of one polarity having associated therewith a source of reactant ioNs at a first region of said duct for forming product ions from the molecules of said component, means including an electrode of opposite polarity at a second region of said duct for attracting and neutralizing said product ions, a passage adjacent to the last-mentioned electrode and separated from said stream for withdrawing molecules of said component to a region separated from said stream and at which the concentration of said component is greater than in said stream, and means for maintaining the pressure in said duct at a level such that the length of the mean free path of said ions is very much less than the dimensions of said duct.

Claim 43

The apparatus of claim 33, said electrodes being located at opposite sides of said duct and said passage being located at the downstream end of the second-mentioned electrode.

Claim 44

The apparatus of claim 34, there being a first grid adjacent to the first-mentioned electrode and a second grid adjacent to the second-mentioned electrode.

Claim 45

Apparatus for detecting a substance in a gas, comprising an envelope enclosing spaced electrodes of opposite polarity and provided with a gas inlet, one of said electrodes having associated therewith means including an ionizing source for producing ions of said substance by ion-molecule reactions, means for establishing a steady unidirectional electric drift field between said electrodes, a pair of ion gates arranged in succession between said electrodes, means for opening said gates in succession, means for detecting ions which drift in said field and are passed by said ion gates in a manner so as to distinguish them, and means for maintaining the pressure in said envelope at a level such that the length of the mean free path of said ions is very much less than the dimensions of said envelope.

Claim 46

Apparatus for detecting a substance in a gas, comprising an envelope enclosing spaced electrodes of opposite polarity and provided with a gas inlet, one of said electrodes having associated therewith means including an ionizing source for producing ions of said substance by ion-molecule reactions, means for establishing a steady unidirectional electric drift field between said electrodes, a pair of ion gates arranged in succession between said electrodes, means for opening said gates in succession, means for detecting ions which drift in said field and are passed by said ion gates in a manner so as to distinguish them, and means for maintaining the pressure in said envelope at a level such that the length of the mean free path of said ions is very much less than the dimensions of said envelope.

Claim 47

Apparatus in accordance with claim 36, said detecting means comprising means connected to the other of said electrodes for producing an output dependent upon the ions reaching said other electrode.

Claim 48

Apparatus in accordance with claim 36, further comprising a pair of grids between said one electrode and one of said ion gates.

Claim 49

Apparatus in accordance with claim 36, wherein each of said ion gates comprises a grid having two interdigitated substantially coplanar sets of grid elements and having means for normally maintaining adjacent elements at equal and opposite potentials with respect to a reference potential, and said means for opening said gates comprising means for placing all of the elements of a grid substantially at said reference potential.

Claim 50

Apparatus in accordance with claim 36, wherein said source is a continuous source.

Claim 51

Apparatus for separating a component of a gas stream, comprising a duct, means for passing said stream through said duct, an electrode of one polarity at one side of said duct, means including a source of ionizing energy associated with said electrode for producing ions of said component by ion-molecule reactions, means including an electrode of the opposite polarity at the opposite side of said duct for neutralizing said ions, an outlet for said component adjacent to the second-mentioned electrode at the downstream end of said duct and separate from the main flow path of said duct for extracting the neutralized ions to a region separated from said stream and at which the concentration of said component is greater than in said stream, and means for maintaining the pressure in said duct at a level such that the length of the mean free path of said ions is very much less than the dimensions of said duct.

Claim 52

Apparatus for separating a component of a gas stream, comprising a duct, means for passing said stream through said duct, an electrode of one polarity at one side of said duct, means including a source of ionizing energy associated with said electrode for producing ions of said component by ion-molecule reactions, means including an electrode of the opposite polarity at the opposite side of said duct for neutralizing said ions, an outlet for said component adjacent to the second-mentioned electrode at the downstream end of said duct and separate from the main flow path of said duct for extracting the neutralized ions to a region separated from said stream and at which the concentration of said component is greater than in said stream, and means for maintaining the pressure in said duct at a level such that the length of the mean free path of said ions is very much less than the dimensions of said duct.

Claim 53

Apparatus in accordance with claim 41, further comprising a pair of grids in said duct adjacent to said electrodes, respectively.

Claim 54

Apparatus in accordance with claim 42, further comprising means for establishing an electric drift field between said electrodes.