US3357233A

US3357233A - Fluid control system for analyzers

Info

Publication number: US3357233A
Authority: US
Inventors: Lewis B Roof
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1964-10-05
Filing date: 1964-10-05
Publication date: 1967-12-12
Anticipated expiration: 1984-12-12

Description

Dec. 12, 1967 a. ROOF 3,357,233

FLUID CONTROL SYSTEM FOR ANALYZERS Filed Oct. 5, 1964 2 Sheets-Sheet 1 FIG.

A T TO/PNEKS- Dec. 12, 1967 'L. B. ROOF 3,357,233

FLUID CONTROL SYSTEM FOR ANALYZERS Filed Oct. 5, 1964 2 Sheets-Sheet 2 CARRIER 44 GAS CHROMATOGRAPHIC 1 COLUMN 24 231 i f r {25 I 35 I i as l l I Y 22 V r I 27 SAMPLE 33 I 2 l 2 J I l 43 2s 36 39 CONTROL I i 4o I I f [4| [29 L TIMER DETECTOR FIG. 3

56 .1 44' f 54 6| 23' I I *fiK 55 CARRIER] I i f GAS I 38! f57 22| 2p SAMPLE f LOOP SAMPLE? I I 43' 29 se g L DETECTOR TIMER CONTROL cAs INVENTOR.

L.B. RooF F/G. 4

A TTORNEVS United States Patent 3,357,233 FLUID CONTROL SYSTEM FOR ANALYZERS Lewis B. Roof, Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware Filed Oct. 5, 1964, Ser. No. 401,403 3 Claims. (Cl. 73-231) ABSTRACT OF THE DISCLQS A fluid control system for supplying to a conduit either a first or a second fluid, in which system the means for switching from the first to the second fluid and vice versa comprises a plurality of fluid actuated fluid stream diverting 3-way fluid valves with one outlet of each valve connected in parallel to said conduit. Said conduit may be used to supply a chromatographic column for analysis of one of said fluids. By using four of said valves, two in series in each of two parallel paths, a more accurately measured sample of said fluid to be analyzed is supplied to said conduit and/ or column.

This invention relates to the distribution of fluids. In another aspect it relates to systems for introducing fluid samples and carrier gas into chromatographic columns.

In various analytical and industrial operations, there is a need for systems which are capable of controlling the flows of fluid streams in a preselected manner. One particular need for such a system occurs in chromatographic analyzers. It is common practice to analyze fluid mixtures by introducing a sample of the mixture to be analyzed into the inlet of the column which contains material that selectively retards the passage of the individual constituents of the sample. A carrier gas is then introduced into the column to push the constituents of the sample toward the outlet. A detector is employed to measure changes in composition of the efiluent from the column in order to provide information which is representative of the various constituents of the sample. Various types of sample valves have been developed to control the introduction of preselected amounts of the sample into the column. These valves generally employ rotary elements or diaphragms which selectively connect various valve ports to perform the necessary switching operations. While these valves are generally satisfactory, they often tend to become complex and expensive to construct and maintain.

In accordance with the present invention, a fluid distribution system is provided wherein moving elements are eliminated from the actual stream switching mechanism. The flow control systems of this invention utilize control valves which are provided with an inlet passage which joins first and second diverging outlet passages. The passages are constructed so that a fluid introduced into the inlet passage can be made to flow through either of the outlet passages. Two control passages are provided in the valve through which small quantities or pulses of control fluids can be introduced. These control passages are positioned so that the introduction of fluid through one of the control passages diverts the main stream into the opposite outlet passages. Similarly, the introduction of control fluid through the second control passage diverts the main stream into the other outlet passage. Two or more of these valves are arranged in accordance with this invention so as to control the addition of a first fluid into a stream of a second fluid. These control systems are particularly effective in introducing samples into chromatographic columns.

Accordingly, it is an object of this invention to provide improved systems for controlling the distribution of fluids.

Another object is to provide novel valve systems for use with analytical instruments.

3,357,233 Patented Dec. 12, 1967 A further object is to provide chromatographic analyzers having improved sample systems incorporated therein.

Other objects, advantages and features of the invention should become apparent from the following detailed description, taken in conjunction with the accompanying drawing in which:

FIGURE 1 shows a control valve of the type employed in the fluid distribution systems of this invention.

FIGURE 2 is a view taken along a line 2-2 in FIG- URE 1.

FIGURE 3 is a schematic representation of a first embodiment of the fluid control system of this invention employed in a chromatographic analyzer. I

FIGURE 4 is a schematic representation of a second embodiment of the fluid control system.

Referring now to the drawing in detail and to FIGURES 1 and 2 in particular, there is shown a control valve of the type employed in this invention. As illustrated in FIG- URE 1, the control valve is formed of two flat plates 10 and 11 which are suitably connected to one another. As illustrated in FIGURE 2, several passages are machined or etched in element 10. The first of these passages is designated as inlet passage 12. The fluid to be controlled is introduced into the valve through passage 12. Passage 12 joins diverging

outlet passages

13 and 14.

Control passages

16 and 17 are formed in element 10 at substantially right angles to inlet passage 12. If a control fluid is introduced into the valve through passage 16 for example, the main fluid stream tends to be displaced downwardly so as to emerge through outlet passage 14. Conversely, the introduction of fluid through passage 17 tends to displace the main stream into outlet passage 13. This operation is described in greater detail hereinafter.

It should be evident that the control valve illustrated in FIGURES 1 and 2 can be formed by various procedures. As illustrated, the passages can be machined or etched in element 10 and can be of generally rectangular cross section. As an alternative, the valve can be formed of a single block wherein the individual passages are drilled. Suitable connectors, not shown, are attached to the ports of each passage to permit conduits to be attached.

A first embodiment of the fluid control system of this invention is illustrated in FIGURE 3. Two

control valves

20 and 21 are employed, each of which can have the configuration illustrated in FIGURES l and 2. The control system of FIGURE 3 is employed to introduce carrier gas and a sample into a chromatographic column 22. A carrier gas is introduced through a conduit 23 which communicates with the inlet port of valve 20.

Conduits

24 and 25 connect one of the outlet passages of valve 20 with the inlet of column 22. A fluid sample to be analyzed is introduced through a conduit 26 which communicates with the inlet passage of valve 21.

Conduits

27 and 25 connect one of the outlet passages of valve 21 with column 22. A conduit 28 extends between the outlet of column 22 and a detector 29. A conduit 30 can be connected between conduit 23 and a second inlet of detector 29.

A conduit 32 introduces a control fluid into the system. In general, it is desirable that this control fluid be the same as the carrier gas to avoid introduction of an additional material into the column.

Conduits

33 and 34, which have

respective control valves

35 and 36 therein, communicate with conduit 32.

Conduits

37 and 38 communicate with conduit 33 downstream of valve 35 and first control passages of

valves

20 and 21, respectively.

Conduits

39 and 40 communicate between conduit 34 downstream of valve 36 and the second control passages of

valves

20 and 21, respectively.

Control valves

35 and 36 are actuated by a timer 41. This timer can be any conventional device, such as motor-driven cams which control electrical switches.

Valves

35 and 36 can be solenoid operated, for example, in response to electrical signals from timer 41.

In normal operation, timer 41 first opens valve 35 and closes valve .36. This introduces control gas into the upper control passages of

valves

29 and 21. The carrier gas thus passes from conduit 23 to conduit 24 and then to column 22. The sample is directed to a vent conduit 43. These flows continue until column 22 is purged and ready for operation. Timer 41 then opens valve 36 and closes valve 35 to direct the carrier gas to a vent conduit 44 and the sample into column 22. Thereafter, timer 41 again opens valve 35 and closes valve 36. This passes additional carrier gas to the column to elute the sample. The volume of sample introduced is determined by the time sample is permitted to flow to the column.

Valves 2i) and 21 are constructed so that only a pulse of control fluid is needed to divert the main stream from one outlet passage to the other. For example, if the flow from conduit 23 is initially through valve to conduit 44, a pulse applied to valve 20 from conduit 37 is sulficient to divert the carrier gas to conduit 24. The carrier gas will then continue to flow in this path, even Without the continued application of fluid from conduit 37, until fluid is applied from conduit 39. Thus, the foregoing control procedure, and the procedures described hereinafter, can be modified to include the application of pulses of control fluids in place of a steady application of control fluid.

It is common practice to employ thermistors as the sensing elements in detector 29. A stream of carrier gas can be passed by conduit 39 to the detector so that thermal conductivity of the carrier gas is compared with the thermal conductivity of the column effiuent. However, this comparison is not always required. Merely measuring changes in thermal conductivity of the eflluent stream is adequate in many analyses. Furthermore, it should be evident that other types of detectors known in the art can be employed in place of thermistors.

A second embodiment of the chromatographic analyzer sample valve system is illustrated in FIGURE 4. The apparatus of FIGURE 4 employs a number of components which are similar to those of FIGURE 3 and which are designated by like prime reference numerals. Conduits 24' and 27' communicate with the inlet of a sample storage loop 50. This loop can be a conduit of any suitable volume to store a desired quantity of sample prior to the introduction thereof into column 22'. The outlet of sample loop 50 is connected by a conduit 51 to the inlet passage of a third control valve 52. A first outlet passage of valve 52 is connected by a conduit 53 to conduit A conduit 44' communicates with the inlet passage of a fourth control valve 54. One of the outlet passages of valve 54 is connected by a conduit 55 to conduit 25.

Conduits

56 and 57 extend between conduit 39 and the upper control passages of respective valves 54 and 52. Conduits 59 extend between conduit 33 downstream of valve and the lower control passages of respective valves 52 and 54.

In normal operation, valve 35' is first opened and valve 36 is closed. This results in carrier gas passing through valve 20, sample loop 50, and valve 52 to column 22. This carrier gas flow purges the sample loop and the column. Valve 36' is then opened and valve 35' is closed. This directs the flow of sample through valve 21', sample loop 50, and valve 52 to a vent conduit 60. The flow continues in this manner for a suflicient time to fill sample loop 50 with sample. Valve 35 is once again opened and valve 36' is closed. This causes the carrier gas to again flow through the sample loop to the column, and in so doing carries the sample into the column for analysis. It should thus be apparent that the system of FIGURE 4 automatically introduces a constant volume of sample into the column, as determined by the volume of the sample loop.

It is desirable that the various conduits employed in the systems of FIGURES 3 and 4 be relatively short in order to avoid stagnant accumulations of fluid therein during switching operations. In addition, it may be desirable to employ an individual flow valve immediately adjacent each of the control valves to provide more rapid control of the sample and carrier gas flows to the control valves.

While the invention has been described in conjunction with presently preferred emodiments, it should be evident that it is not limited thereto.

What is claimed is: 1. In an analyzer comprising a column adapted to contain a material that selectively retards Passage therethrough of individual constituents of fluid mixtures to be analyzed, a source of carrier gas, a fluid sample source, and means communicating with the outlet of said column to detect changes in composition of the eflluent from the column; a system to introduce carrier gas and sample into the column comprising:

first and second members, each having a fluid inlet passage which joins first and second diverging outlet passages, and first and second control passages which communicate with the junction of the inlet and outlet passages in directions so that the introduction of fluid into said first control passage directs fluid from said inlet passage to said second outlet passage and the introduction of fluid into said second control passage directs fluid from said inlet passage to said first outlet passage; first conduit means communicating between said carrier gas source and the inlet passage of said first member;

second conduit means communicating between said sample source and the inlet passage of said second member; third conduit means connecting the second outlet passage of said first member and the first outlet passage of said second member with the inlet of said column;

fourth conduit means communicating with the second control passage of said first member and the second control passage of said second member to introduce fluid simultaneously therein;

fifth conduit means communicating with the first control passage of said first member and the first control passage of said second member to introduce fluid simultaneously therein;

sixth conduit means to introduce a fluid, a first valve connecting said sixth conduit means to said fourth conduit means, a second valve connecting said sixth conduit means to said fifth conduit means, and control means to open and close said first and second valves selectively.

2. A fluid control system comprising:

first, second, third and fourth members, each having a fluid passage which joins first and second diverging outlet passages, and first and second control passages which communicate with the junction of the inlet and outlet passages in directions so that introduction of fluid into said first control passage directs fluid from said inlet passage to said second outlet passage and introduction of fluid into said second control passage directs fluid from said inlet passage to said first outlet passage;

first conduit means communicating with the inlet passage of said first member to introduce a first fluid into the system;

second conduit means communicating with the inlet passage of said second member to introduce a fluid into the system;

third conduit means communicating between the first outlet passage of said first member and the inlet passage of said third member;

fourth conduit means communicating between the second outlet passage of said first member and the first outlet passage of said second member;

fifth conduit means communicating between said fourth conduit means and the inlet passage of said fourth member;

sixth conduit means communicating with the second outlet passage of said third member and the first outlet passage of said fourth member to remove fluid from the system;

seventh conduit means communicating with the first control passages of said first and second members and the second control passages of said third and fourth members to introduce fluid simultaneously therein;

eighth conduit means communicating with the second control passages of said first and second members and the first control passages of said third and fourth members to introduce fluid simultaneously therein; ninth conduit means to introduce a fluid, a first valve connecting said ninth conduit means to said seventh conduit means, and a second valve connecting said ninth conduit means to said eighth conduit means.

3. In an analyzer comprising a column adapted to contain a material that selectively retards passage therethrough of individual constituents of fluid mixtures to be analyzed, a source of carrier gas, a fluid sample source, and means communicating with the outlet of said column to detect changes in composition of the efliuent from the column; a system to introduce carrier gas and sample into the column comprising:

sixth conduit means communicating with the second outlet passage of said third member and the first out let passage of said fourth member to remove fluid from the system;

seventh conduit means communicating with the first control passage of said first and second members and the second control passages of said third and fourth members to introduce fluid simultaneously therein;

eighth conduit means communicating with the second control passages of said first and second members and the first control passages of said third and fourth members to introduce fluid simultaneously therein;

ninth conduit means to introduce a fluid, a first valve connecting said ninth conduit means to said seventh conduit means, a second valve connecting said ninth conduit means to said eighth conduit means, and control means to open and close said first and second valves selectively.

References Cited UNITED STATES PATENTS 3,016,063 1/1962 Hausmann 235-201 3,069,898 12/1962 Vesper 7323.1 3,170,476 2/1965 Reilly 13781.5 3,198,431 8/1965 Gesell 1378l.5

49 RICHARD C. QUEISSER, Primary Examiner.

JAMES J. GILL, Examiner.

C. A. RUEHL, Assistant Examiner.

Claims

1. IN AN ANALYZER COMPRISING A COLUMN ADAPTED TO CONTAIN A MATERIAL THAT SELECTIVELY RETARDS PASSAGE THERETHROUGH OF INDIVIDUAL CONSTITUENTS OF FLUID MIXTURES TO BE ANALYZED, A SOURCE OF CARRIER GAS, A FLUID SAMPLE SOURCE, AND MEANS COMMUNICATING WITH THE OUTLET OF SAID COLUMN TO DETECT CHANGES IN COMPOSITION OF THE EFFLUENT FROM THE COLUMN; A SYSTEM TO INTRODUCE CARRIER GAS AND SAMPLE INTO THE COLUMN COMPRISING: FIRST AND SECOND MEMBERS, EACH HAVING A FLUID INLET PASSAGE WHICH JOINS FIRST AND SECOND DIVERGING OUTLET PASSAGES, AND FIRST AND SECOND CONTROL PASSAGES WHICH COMMUNICATE WITH THE JUNCTION OF THE INLET AND OUTLET PASSAGES IN DIRECTIONS SO THAT THE INTRODUCTION OF FLUID INTO SAID FIRST CONTROL PASSAGE DIRECTS FLUID FROM SAID INLET PASSAGE TO SAID SECOND OUTLET PASSAGE AND THE INTRODUCTION OF FLUID INTO SAID SECOND CONTROL PASSAGE DIRECTS FLUID FROM SAID INLET PASSAGE TO SAID FIRST OUTLET PASSAGE; FIRST CONDUIT MEANS COMMUNICATING BETWEEN SAID CARRIER GAS SOURCE AND THE INLET PASSAGE OF SAID FIRST MEMBER; SECOND CONDUIT MEANS COMMUNICATING BETWEEN SAID SAMPLE SOURCE AND THE INLET PASSAGE OF SAID SECOND MEMBER; THIRD CONDUIT MEANS CONNECTING THE SECOND OUTLET PASSAGE OF SAID FIRST MEMBER AND THE FIRST OUTLET PASSAGE OF SAID SECOND MEMBER WITH THE INLET OF SAID COLUMN; FOURTH CONDUIT MEANS COMMUNICATING WITH THE SECOND CONTROL PASSAGE OF SAID FIRST MEMBER AND THE SECOND CONTROL PASSAGE OF SAID SECOND MEMBER TO INTRODUCE FLUID SIMULTANEOUSLY THEREIN; FIFTH CONDUIT MEANS COMMUNICATING WITH THE FIRST CONTROL PASSAGE OF SAID FIRST MEMBER AND THE FIRST CONTROL PASSAGE OF SAID SECOND MEMBER TO INTRODUCE FLUID SIMULTANEOUSLY THEREIN; SIXTH CONDUIT MEANS TO INTRODUCE A FLUID, A FIRST VALVE CONNECTING SAID SIXTH CONDUIT MEANS TO SAID FOURTH CONDUIT MEANS, A SECOND VALVE CONNECTING SAID SIXTH CONDUIT MEANS TO SAID FIFTH CONDUIT MEANS, AND CONTROL MEANS TO OPEN AND CLOSE SAID FIRST AND SECOND VALVES SELECTIVELY.