US3898041A

US3898041A - Fluid sampler apparatus and method

Info

Publication number: US3898041A
Application number: US346041A
Authority: US
Inventors: Thomas M Stephens; Robert J Joyce
Original assignee: Envirotech Corp
Current assignee: Rosemount Inc
Priority date: 1971-03-01
Filing date: 1973-03-29
Publication date: 1975-08-05
Anticipated expiration: 1992-08-05

Abstract

A fluid sampler having a gas-tight tube which carries a boat with a sample-receiving cavity. Means operable from the exterior of the tube engages the boat and moves the same from a predetermined loading station in sequence to a warming station, and pyrolyzing station, and returning to a cooling station and finally back to the loading station. The boat is moved by a rod assembly actuated by a gas operated reciprocal piston assembly with intermediate stop positions provided by gas bleed valves in the piston housing side walls intermediate the end walls. The method comprises using the above apparatus for moving the boat to and from the analysis equipment.

Description

United States Patent Stephens et al. Aug. 5, 1975 FLUID SAMPLER APPARATUS AND 3.567388 3 1971 Kapfi' 23 253 PC METHOD 3.647385 3/l972 Stephens t, 23/230 PC [75] Inventors: gggzz j g gl gfig iil i Primary E.\'aminerR0bert MY Reese y p Attorney, Agent, or Firm-R0bert E. Krebs; Robert R. Calif.

Punch [73] Assignee: Envirotech Corporation, Menlo Park 57 1 ABSTRACT [22] Flled: 1973 A fluid sampler having a gas-tight tube which carries a [21] Appl. No.1 346,041 boat with a sample-receiving cavity. Means operable from the exterior of the tube engages the boat and kelted Apphcauon Data moves the same from a predetermined loading station Continuation Of $61. NO. i]9,672 MfllCh i. 197] in equencg a warming tation and pyrolyzing tu. abandoned tion, and returning to a cooling station and finally back to the loading station. The boat is moved by a [52] Cl 23/230 PC; 23/253 PC rod assembly actuated by a gas operated reciprocal [51] i 31/12 piston assembly with intermediate stop positions pro- [58] held of Search 23/230 230 253 vided by gas bleed valves in the piston housing side 23/259 walls intermediate the end walls. The method comprises using the above apparatus for moving the boat [56] References cled to and from the analysis equipment. UNITED STATES PATENTS 2,669.504 2/1954 Halvorson et al H 23/230 PC 13 Clams 5 Drawmg guns FEJEWEB AUS 5 75 SkiiEI 1 SF 3 INVENTORS Thomas M Stephens Robert oyce M, W 71! My F/XTEFITEU 51975 $898,041

SHEET 3 SF 3 INVENTORS Thomas M. Stephens BY Robert J. Joyce FLUID SAMPLER APPARATUS AND METHOD This is a continuation of application Ser. No. 119,672, filed Mar. 1, l97l, and now abandoned.

BACKGROUND OF THE INVENTION It is difficult to efficiently feed a series of fluid samples into chemical analysis equipment, in particular, of the microcoulometric titration type. For oxidative or reductive analysis, utilizing a pyrolysis tube, samples are conventionally deposited directly within the tube resulting in inaccuracies due to contaminants from prior samples. Furthermore, in such a system there is no capacity to analyze the fluid in two stages, the first stage performed at a temperature just sufficient to evaporate the readily vaporizable portion of the sample and a second pyrolysis stage. Such a two stage analysis is an effective tool in characterizing the components of the sample. There is, therefore, a need for an efficient fluid sample handling system capable of stage operation.

One device for handling solids and semi-viscous samples is described in an application entitled Solid Sampler, Apparatus and Method in the name of Thomas M. Stephens, filed on Feb. 20, [969, and bearing the Ser. No. 800,946. That system is rather complex of operation and requires individual manual handling of multiple sample boats. That system has been modified to include an external syringe for filling the boats. The system is not capable of automatic periodic sampling of continuously moving fluid streams. such as sewage. for determining levels of contamination.

SUMMARY OF THE INVENTION AND OBJECTS The fluid sampler consists of a tube sealed against ambient gas which forms a feed-through passage. A

boat with a cavity for receiving sample is carried by the tube. Means is provided which is operable from the exterior of the tube for engaging the boat and for moving the same in a pathway at least part of which extends along the feed-through passage and is capable of stopping the boat at a predetermined loading station along the feed-through passage and at least one other predetermined station spaced apart therefrom along the pathway. Means is provided external to the tube for supplying sample into the boat at the sample loading station.

One embodiment of the boat engaging and moving means includes a rod assembly interconnected with means for stopping the boat at a sample loading station, a pyrolysis station, and intermediate warming and cooling stations. The warming and pyrolysis stations may be heated from the same source. Actuation of the rod assembly is by gas operated reciprocal piston assembly with intermediate stop positions provided by gas bleed valves in the piston housing side walls intermediate the end walls. When these valves are in an open position, the gas applied to the upstream side of the piston drives it to a position on a downstream side of the valve at which time the driving force of the pressurized gas is eliminated to form intermediate stop positions to the piston. The boat is stopped at the above stations corresponding to the piston stops by linkage through the rod assembly. The pyrolysis station is within the pyrolysis tube of a furnace interconnected to the feed-through passage so that the boats can be moved by the push rod assembly directly into the pyrolysis tube and away from the same. The apparatus also includes a titration cell for making coulometric analyses of the gasses evolving from the samples carried by the boats under the influence of heating.

The method comprises the steps which are utilized in operating the above sampler including supplying fluid sample from an exterior source to the boat at a sample loading station, moving the boat from the sample loading station to a second station (e.g. a warming station) moving the boat further to a third station (e.g. a pyrolysis station) and returning the boat to the sample loading station to complete the cycle. A cooling station may also be included intermediate the sample loading and pyrolysis zone, A carrier gas sweeps the gasses vaporized during warming and pyrolysis away from the boat for analysis by a technique such as coulometric titration.

In general, it is an object of the present invention to provide a fluid sampler apparatus and method for the handling and analysis of fluid samples.

It is another object of the invention to provide a sampler of the above character which can be utilized with reductive or oxidative type analyses.

It is another object of the invention to provide an apparatus of the above character in which a boat is initially filled with sample and moved to a plurality of sta tions whereat a plurality of functions are performed and in which the boat is returned to the starting point.

It is a further object of the invention to provide an apparatus and method of the above character for automatically withdrawing a sample from a continuous stream and analyzing the same at predetermined time intervals.

Additional objects and features of the invention will appear from the following description in which the preferred embodiments are set forth in detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a front elevational view with an apparatus incorporating the present invention utilizing the fluid sampler.

FIG. 2 is a cross-sectional view of the fluid sampler.

FIG. 3 is an enlarged cross-sectional view ofthe sam ple supply assembly and illustrating two stations for the boat.

FIG. 4 is an end elevational view of the apparatus shown in FIG. 2.

FIG. 5 is a top elevational view of the apparatus shown in FIG. 4 taken along the line 5-5 illustrating the piston assembly and associated valving according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus illustrated in the drawings consists of a fluid sampler 10 which is adapted to supply sample to be analyzed as hereinafter described to a pyrolysis tube 11, formed of heat resistive material such as quartz, of a pyrolysis furnace I2. The apparatus also includes a strip chart recorder 13 and a control console 14. A titration cell assembly 16 is connected to the pyrolysis furnace 12. The fluid sampler may be enclosed in a housing 17 having a control panel 18.

The fluid sampler 10 consists of a tube I9 sealingly fitted to pyrolysis tube ll having a feed-through passage in which a boat 21 is carried. Boat engaging and moving means, to be described hereinafter, is provided for moving the boat along a pathway extending between passage and pyrolysis tube 1]. The boat moving means is capable of stopping the boat at a predetermined loading station 23 and at other stations to be described hereinafter. Fluid sample supply means 24 is supplied to accurately meter the amount of fluid sample deposited in said boat.

Tube assembly I) is formed of a heat resistive material such as quartz to withstand the high heat generated in the connecting pyrolysis furnace. Tube assembly 19 includes two chimney portions 19a and 19h provided with gas-tight fittings 27a and 27b to accommodate inlet ducts described hereinafter. Tube assembly 19 is sealed against ambient gasses at one end by closure cap 25.

Sample supply means 24 includes an outlet needle 26 projecting through fitting 27a in chimney 19a so that the passage between needle 26 and tube assembly 19 is sealed against ambient gasses. Needle 26 is fitted to outlet duct 29 of supply means 24. Supply means 24 serves to automatically supply an accurately metered sample through needle 26. Supply means 24 includes a frame 30 from which project horizontal upper and lower supporting plates 3i and 32 respectively. A sampler plate 33 is provided with cylindrical openings 34a and 34b and is mounted for reciprocal movement between two positions. Aligned fluid sample inlet and outlet ducts 36 and 37 project through supporting plates 32 and 3], respectively. Aligned inlet and outlet duets 38 and 29 for pressurized carrier gas from a source, not shown. project through supporting plates 3| and 32 respectively. Carrier gas is also supplied from the same source through duct 28 mounted to fitting 27b to sweep gas through tube assembly 19. In a first sample bypass position of plate 33 illustrated in HQ 3, opening 34a is in registry with aligned sample ducts 36 and 37, and opening 34b is in registry with aligned carrier gas ducts 3S and 29. in this manner the carrier gas continuously sweeps tube assembly l9 while sample bypasses the needle. Flow between ducts 36 and 37 is in an upward direction to assure that cavity 34a is completely filled with sample. At a predetermined time, plate 33 is actuated to a second position to move opening 340 containing a measured quantity of sample. into registry with ducts 29 and 38 so that the fluid sample is forced into boat 21 by the carrier gas.

Plates 3] are mounted to plates 32 by means of three spaced apart and aligned spring loaded bolts mounted at each side of sampler plate 33 serving to provide an even weight distribution at the mating upper and lower surfaces of plate 33. This avoids unevenness of pressure which could provide spaces between the mating plates through which leakage of sample could occur.

Movement of sampler plate 33 is actuated by air or other gas pressure supplied through line 87 to a piston cylinder 4! which carries a sliding piston connected to linking piston rod linkage assembly 42. A U-shaped air bypass fitting 43 communicates at each end with portions of cylinder 41 on each side of the piston. An air outlet duct 40 is provided for cylinder air discharge from either side of the piston. Solenoid valve actuates the direction of air either to the inlet side of cylinder 41 or through fitting 43 to the other side with a corresponding opposite setting for air discharge. in this manner the piston moves in forward or reverse direc tions with corresponding movement of sampler plate 33 interconnected by linkage assembly 42.

Boat 21 is formed of a heat resistive material such as quartz, alumina. and the like, which is capable of withstanding the temperatures of pyrolysis. The bottom of the boat is formed in a curved planar configuration to conform to the lower surface of tube assembly 19 so that it may be moved along the tube without tipping. The walls of the boat are formed to include a central cavity with the front wall of the boat being substantially higher than the rear wall of the same. The front wall provides a backing for heat resistive fluid absorbent material 47 such as quartz wool or the like which projects above the lower level of the needle to drain the sample by capillary action. The rear wall of the boat must be lower than the needle to provide clearance for movement of the boat toward the pyrolysis tube as described hereinafter. The higher front wall also provides a stop for the needle which projects therebelow. The rear wall of the boat is provided with a small hole or loop for linking with a hooked portion of the push rod assembly described hereinafter.

Boat 21 is movable by the means described hereinafter in a series of stations to complete a single cycle. In order of advancement. the boat proceeds from the sample loading station 23 to a warming station 48 and then to pyrolysis station 49 in a forward direction and, in a reverse direction to a cooling station 50 and to sample loading station 23. As aforementioned, the sample is heated in the pyrolysis tube 11 of the pyrolysis furnace 12 for either oxidative or reductive reaction. The positioning of warming station 48 is selected to be at a distance from the pyrolysis furnace at which the sample is heated to a sufficient extent to vaporize the same but not sufficiently for pyrolytic reaction. To accommodate different liquid boiling points, the station position may be varied. As described hereinafter, this preliminary heating stage provides an additional tool for analysis of the sample. The cooling station is provided with a large heat sink suitably formed of a surrounding block 51 having a large capacity for heat transfer such as formed of aluminum. A cushioning sleeve 52 formed of a heat conductive material such as aluminum foil is provided between block 51 and the relatively fragile quartz tube 19 (FIG. 3).

A boat engaging and moving means is provided including a push and pull rod assembly interconnected to a reciprocal piston assembly 59 to be described hereinafter. The push and pull rod assembly comprises a relatively thin wire 56 capable of withstanding heat generated in the pyrolysis tube (e.g. platinum) embedded in a sturdy backup rod 57 of less expensive material such as stainless steel and having a larger diameter for rigidity. The free end of wire 56 includes a hooking portion which fits into the opening in the rear wall of boat 2i. Rod 57 slideably projects through an opening enclo sure cap 25 into tube assembly 19 in a substantially gastight fit without excessive frictional resistance. Rod 57 is interconnected through linkage assembly 58 to reciprocal piston assembly 59.

Reciprocal piston assembly 59 consists of piston cylinder 60 which slideably carries piston 61 having a front face 61a. Piston 61 is provided with a sealing O- ring and an accommodating annular groove to prevent air leakage therearound when sliding along the side wall of cylinder 60. The piston is interconnected to linkage assembly 58 by piston rod 62 threadingly received within a projecting portion of the rear of piston 61 at one end and connected by screws 63 to upright arm 64 of linkage assembly 58 at the other end. The lower portion of arm 64 is slideably carried by a guide slot 66 in a supporting base plate 67.

Piston cylinder 60 is carried at each end within cylindrical recesses of rectangular block like

end walls

68 and 69 at opposite ends of the cylinder to form a gastight cylinder chamber 75. Sealing O-rings 70 are provided in accommodating annular grooves within the recesscs of

blocks

68 and 69 to prevent air leakage from chamber 75.

End walls

68 and 69 are seated on supporting base plate 67. An upper supporting plate 71, carried by the upper surfaces of

blocks

68 and 69, seats the lower surfaces of block 51 and cap which cooperate to support tube assembly 19.

End walls

68 and 69 of cylinder 60 are provided with gas inlet and outlet openings 73 and 74, respectively. In addition, linearly spaced gas outlet bleed

openings

76 and 77 are provided in the cylinder side wall

intermediate end walls

68 and 69.

Openings

73, 74, 76 and 77 are connected by

suitable tubing

79, 78, 80 and 81, respectively, to independently

operable solenoid valves

83, 82, 84 and 86, respectively. Pressurized gas is supplied from a source, not shown, through a line 87 which is split into

lines

88 and 89 to supply

solenoids

82 and 83, respectively, which, in turn, are provided with

respective vent lines

90 and 91. Solenoids 84 and 86 are provided with a common outlet vent 92.

Solenoid 82 is selectively operable between an open position in which air supplied through pressure line 87 is directed through open vent 90 and a closed position in which vent 90 is sealed and the air is directed through tubing 78 through opening 73 into piston chamber 75. Piping 78 is at all times in communication with pressure line 88, the direction of flow in tubing 78 being determined by the opening or closing of vent 90. Solenoid 83 operates in a substantially identical man ner to solenoid 82.

Solenoid valve 84 is selectively operable between an open and closed position. In the open position, gas is permitted to exit from cylinder 75 through vent 92 and in a closed position, the vent is sealed against exit gas flow. Solenoid valve 86 is operable in a similar manner.

As described hereinafter, the solenoids are set to open and close the valves in a predetermined time sequence. In one construction of the timing mechanism, not shown, a gear motor having a rotating shaft with a number of cams is employed to sequentially operate a number of microswitches which open and close the solenoid valves.

In one operational sequence of reciprocal piston assembly 59, piston 61 is initially at the right hand portion of cylinder 75 as illustrated in FIG. 2 at which time boat 21 is at sample loading station 23. The setting of solenoid valves for this position is as follows:

Valves

82, 84 and 86 are closed and valve 83 is open. In this manner, pressurized air in line 88 is directed through open ing 74 and is urged against piston front face 610 to slide the piston to the position illustrated in FIG. 2. Air at the back side of the piston is permitted to exit through opening 73 and out vent 91 so that there is no back pressure.

In order to move boat 21 to the second or warming station 48, the solenoid valve settings of

valves

82, 83, and 84 are simultaneously reversed while the valve 86 remains closed. Thus, air is applied to the back side of piston 61 through solenoid valve 83 while solenoid valve 82 is set to permit air on the opposite side of the piston to exit through vent 90. Solenoid valve 84 in an open position serves as a bleed or bypass duct for the pressurized air at the back side of the piston after movement of the same to the left of bleed hole opening 76. Thus, the driving force of the pressurized gas in the upstream side of chamber is dissipated by channel ling through opening 76 and out vent 92 to create an intermediate stop position for the piston with corre sponding movement of boat 21 through linkage assembly 58 and the aforementioned connecting rod assembly.

To move boat 21 to the third or pyrolysis station 49, the setting of solenoid valve 84 is reversed with the remainder of the solenoid valve in the same position. In this manner. the pressurized gas supplied through line 79 drives piston 61 against cylinder end wall 69 since bypass valve 84 is in a sealing position.

Movement of boat 21 from pyrolysis station 49 in a reverse direction to the fourth or cooling station 50 is accomplished by a simultaneous resetting of solenoid valve 82 from an open to a closed position, solenoid valve 83 from a closed to an open position, and solenoid valve 86 from a closed to an open position and leaving solenoid valve 84 in the prior closed position. In this manner, pressurized gas from line 88 is directed through tubing 78 and opening 74 and urged against front piston face 61a to drive piston 61 toward end wall 68. When face 61a slides to the right of opening 77, as illustrated in FIG. 2, the pressurized gas flowing into chamber 75 through opening 74 is permitted to flow through opening 77 and out vent 92. At the same time, solenoid valve 83 is in an open position to permit air between piston 61 and wall 68 to exit from vent 91 so that no back pressure is created. With the piston at this predetermined stop position, boat 21 is correspondingly moved to the cooling station 50, illustrated in phantom in FIG. 2.

To return piston 61 to the starting position and correspondingly return boat 21 to the sample loading station, solenoid valve 86 is actuated to a closed position and the remainder of the solenoid valves remain in their former position. This valve setting is the same as that above-described for the initial piston stop.

In the above type of air-driven piston assembly, the speed of the boat 21 between stations may be controlled by variance in the gas supply pressure or in the outlet tubing i.d., a small i.d. producing a back pressure and a consequent braking effect. It is important to maintain a relatively low boat speed to avoid spillage of sample.

The pyrolysis furnace 12, the strip chart recorder 13, the control console 14 and the titration cell 16 are substantially conventional and, therefore, will not be described in detail. By way of example, they can be of the type supplied by lnfotronics Instrument Corporation of Mountain View, California, as a type (-200 microcoulometric titration system of either the oxidative or reductive type. It should be further understood that the fluid sampler apparatus of the present invention may be employed in conjunction with other analytical systems such as a flame detector and the like.

Operation of the fluid sampler according to the present invention may now be briefly described with respect to a reductive pyrolytic reaction with hydrogen as the reactive gas. Since hydrogen is explosive in the presence of oxygen, it is first necessary to purge the tube assembly 19 and pyrolysis tube ll with an inert gas, such as helium or argon, to assure the absence of oxygen or other contaminating gasses from the system. For the same purpose, it is desirable to maintain a posi tive flow pressure toward the pyrolysis tube throughout the entire process so that gasses may not back into the system from that end. The inert gas may be supplied through duct 28 and simultaneously through needle 26, suitably from the same source. The gas supplied through duct 28 serves to sweep any dead spaces in the area to the right of needle 26 as shown in FIG. 3. After sweeping for a sufficient period of time. valving, not shown, is switched and hydrogen is substituted for the inert gas and supplied through needle 26 and duct 28 to sweep and thereby condition the catalyst within the pyrolysis tube. During this time, sample is continuously flowing through duct 36 upwardly into openings 34 and out duct 37 for discharge so that opening 341: is continuously filled with a metered amount of sample. At this time, the boat is positioned at the sample loading station 23. To load the boat with sample, solenoid valve 45 is actuated to move cylinder 41 and. correspondingly, sampler plate 33 so that opening 340, filled with sample, is moved into registry into ducts 38 and 29. At this time the hydrogen gas under pressure forces the sample through needle 26 into boat 2]. The quartz wool in the boat serves to provide a capillary path for the last remnants of sample from the end of needle 26. During the movement of plate 33 and the filling of boat 21, the gas flow through needle 26 is discontinued so that only gas flowing through duct 28 maintains a positive pressure in the direction of the pyrolysis tube to assure that extraneous gasses are not allowed to flow into the system.

The above series of steps may be automated and set into motion in a timed sequence which is coordinated with the remainder of the operational steps described hereinafter. This timing may be set into motion by a single dial on control panel 18.

The boat is retained in the sample loading position for sufficient time (cg. seconds) after initiating filling so that substantially all of the sample has drained into the cavity of the boat. At this time, piston 6] of reciprocal piston assembly 59 is moved to a second stop position by changing the setting of appropriate solenoid valves as discussed above, so that the boat is moved by rod assembly 57 to warming station 48. This station is maintained at a temperature sufficient to evaporate the liquid portion of the sample but insufficient to allow pyrolytic reduction by the sweeping hydrogen. With sewage water or other water based sample, the temperature should be sufficient to assure the evaporation of all water (eg. on the order of lOO-l 50C). Heat emitted from the pyrolysis furnace is suitably employed as the heat source for warming the sample at the warming station. Accordingly, the placement of that station is carefully chosen to be at a suitable distance from the pyrolysis furnace. A typical holding time at the warming station to evaporate the liquid solvent or carrier is on the order of 45 seconds. During this time, the sweep gas carries the vaporized solvent into the titration cell or other analytical equipment for a preliminary or first stage analysis. This may reveal certain contaminants or other components of the solvent which might otherwise be intermingled with the reduced gasses formed during pyrolysis to produce an error in the analytical results.

After the above retention time at the warming station, the automatic timer resets the solenoid valve in a manner as above described to move piston 61 into contact with end wall 69. This movement of the piston causes rod assembly 53 to push boat 21 to the pyrolysis station located within the pyrolysis furnace. Suitable temperatures in the pyrolysis zone are on the order of 700 to l0U0C. During pyrolysis, the sweeping hydrogen gas reacts with the nitrogen content of the sample to form ammonia which is swept by the carrier gas into the microcoulometric titration cell 16 for analysis. A suitable holding time to assure substantial completion of the pyrolytic reaction is on the order of 5 minutes.

After pyrolysis, the automatic timer is again actuated to change appropriate settings of the solenoid valves of reciprocal piston assembly 59 to move piston 61 into a position in which rod assembly pulls boat 21 in the reverse direction to the cooling station 50. The large aluminum block provides a fine heat sink for quickly cooling the boat to temperatures not much in excess of ambient room temperatures in a holding time on the order of l0 seconds. It is desirable to cool the boat before return to the sample loading station so that the needle projecting into the vicinity of the boat is always retained at approximately room temperature. In the absence of such a cooling step, the boat which may be at a temperature on the order of 700C or higher would be returned directly to the sample loading station to heat the needle to relatively high temperatures. This could vaporize contaminants on the needle which may be present from previous sample loadings but which would not vaporize at room temperatures.

Thereafter, the cycle is completed by movement of the boat to the initial loading position by appropriate resetting of the solenoid valve of piston assembly 59 as previously described.

After completion of one cycle, new samples may be analyzed in subsequent cycles. Contaminants from the previous sample which could interfere with analysis of any subsequent samples have been pyrolyzed and swept away by the carrier gas.

Purging with inert gas is only necessary during the start-up operation and, thereafter, the continuous flow of hydrogen gas at a positive pressure guards against the introduction of contaminants.

Where the system is used for an oxidative type analysis, rather than the above described reductive reaction, no preliminary inert gas sweep is necessary. Oxygen is initially supplied through needle 26 and duct 28 to sweep out any contaminants. There is no problem as with hydrogen of forming an explosive mixture. In the oxidative approach, sulfur is reacted with the oxygen carrier gas to form sulfur dioxide which is analyzed in the microcoulometric titration assembly.

The above system is particularly well adapted for drawing a small sample portion from a continuous fluid stream at selected time intervals over an extended period of time. For example, it may be desirable to analyze treated sewage water for contaminant to test whether it is safe for discharge into large bodies of water or for other uses. The system could be programmed to analyze, for example, four samples a day for an indefinite period of time. In such an analysis system. contaminants which could conceivably remain in the system after the previous analysis would be averaged out without significantly altering the overall average contamination history of the sewage.

It should be understood that it is contemplated within the present invention to operate a push rod assembly 53 by means other than piston assembly 59 such as by automated stop tabs along a linear piston. Furthermore, rod assembly 53 could be manually operated as with appropriate markings on the external rod to indicate the proper stations for the boat.

For single cycle operation, the fluid sample supply assembly may be replaced with a syringe for metering the desired quantity of sample into the boat. After each cycle, the syringe would be replaced with another syringe containing another sample.

We claim:

1. In a method for handling a fluid sample to analyze the same utilizing a boat having a cavity for receiving sample, the steps of forming a chamber about said boat sealed against ambient gas and having a feed-through passage for the boat, supplying fluid sample from a source exterior of said chamber to the boat located at a sample loading station within said chamber while maintaining the chamber seal, moving said boat from said sample loading station in a pathway at least a portion of which extends along said feed-through passage to a warming station while maintaining the chamber seal, maintaining said warming station at a temperature sufficient to volatilize the liquid portion of the sample and dissolved gasses without pyrolyzing the sample. holding said boat at said warming station for a selected period of time to volatilize said liquid portion and dissolved gasses, moving said boat to pyrolysis station, holding said boat at said pyrolysis station while heating the same to pyrolytically react the sample, and returning said boat along said pathway to said sample loading station to complete one cycle.

2. A method as in claim 1 in which said sample is supplied in a metered amount to the boat under pressure created by carrier gas.

3. A method as in claim 1 in which the cycle is repeated for analysis of another sample supplied to said boat after the boat returning step.

4. A method as in claim 3 in which the fluid sample is a small portion drawn off from a continuous stream of fluid at selected time intervals for analylsis.

5. A method as in claim 3 in which said boat is moved from said pyrolysis station to a cooling station inter posed along said pathway between said pyrolysis station and sample loading station prior to movement to the latter station, the boat is held at said cooling station for a selected period of time sufficient to substantially decrease the temperature of the boat, and thereafter the boat is returned to said sample loading station.

6. A method as in claim 5 in which the temperature of the boat when returned to the sample loading station is not substantially in excess of room temperature.

7. Apparatus for conveying small samples of materials into a pyrolysis tube for subsequent analysis comprising:

a. Frame means;

b. A generally sealed loading tube mounted on said frame means and connected at one end directly in communication with the pyrolysis tube to effectu ate a continuation thereof;

c. A sample boat slidably disposed in said loading tube, said boat having a cavity for receiving a sample to be analyzed;

d. Loading means connected near the end opposite of said one end of said loading tube to conduct a sample of material into said boat at a sample loading station in said loading tube;

e. Means connected to said boat for moving it through the loading tube into the pyrolysis tube; said moving means including: l) a rod connected at one end to said boat, and (2) a reciprocative assembly, comprising a cylinder stationarily fixed relative to said frame and a piston attached to said rod and slidably disposed within said cylinder;

f. Gas valve means in fluid communication with said cylinder to selectively position said piston at least at two predetermined positions therein, thereby to correspondingly position said boat at predetermined stations within said loading tube and the pyrolysis tube in response to gas pressure applied through said valve means against said piston, one of said stations being said loading station and another being a pyrolysis station.

8. Apparatus according to claim 7 wherein said loading means comprises a fluid sample duct connected in fluid flow communication with said loading tube at said loading station.

9. Apparatus according to claim 8 further including a carrier gas duct means connected in fluid flow communication with said loading tube at a location intermediate the location of said fluid sample duct and said end of said loading tube away from the pyrolysis tube for introducing carrier gas into said loading tube to maintain positive flow pressure toward the pyrolysis tube.

10. Apparatus according to claim 8 including slide valve means connected to said fluid sample duct for metering predetermined amounts of sample through said sample duct into said boat at said loading station, said valve means including means to maintain a continuous flow of the sample material therethrough when said boat is not being loaded.

11. Apparatus according to claim 7 wherein said gas valve means further includes means to define two intermediate stopping positions thereby to provide a warming station and a cooling station for said boat intermediate said loading and pyrolysis stations.

12. Apparatus according to claim 11 including means in heat communications with said loading tube for heating said warming and pyrolysis stations to varying de grees and means for cooling the boat at said cooling station.

13. Apparatus according to claim ll wherein said gas valve means includes two gas bleed valve means mounted in flow communication with respective spaced-apart locations in the interior of said cylinder intermediate its ends, said bleed valve means each being selectively and independently operable between an open and closed position for locating said boat at said warming and cooling stations within said loading tube.

at k 4: m

Claims

1. IN A METHOD FOR HANDLING A FLUID SAMPLE TO ANALYZE THE SAME UTILIZING A BOAT HAVING A CAVITY FOR RECEIVING SAMPLE, THE STEPS OF FORMING A CHAMBER ABOUT SAID BOAT SEALED AGAINST AMBIENT GAS AND HAVING A FEED-THROUGH PASSAGE FOR THE BOAT, SUPPLYING FLUID SAMPLE FROM A SOURCE EXTERIOR OF SAID CHAMBER TO THE BOAT LOCATED AT A SAMPLE LOADING STATION WITHIN SAID CHAMBER WHILE MAINTAINING THE CHAMBER SEAL, MOVING SAID BOAT FROM SAID SAMPLE LOADING STATION IN A PATHWAY AT LEAST A PORTION OF WHICH EXTENDS ALONG SAID FEED-THROUGH PASSAGE TO A WARMING STATION WHILE MAINTAINING THE CHAMBER SEAL, MAINTAINING SAID WARMING STATION AT A TEMPERATURE SUFFICIENT TO VOLATILIZE THE LIQUID PORTION OF THE SAMPLE AND DISSOLVED GASSES WITHOUT PYROLYZING THE SAMPLE, HOLDING SAID BOAT AT SAID WARMING STATION A SELECTED PERIOD OF TIME TO VOLATILIZE SAID LIQUID PORTION AND DISSOLVED GASSES, MOVING SAID BOAT TO PYROLYSIS STATION, HOLDING SAID BOAT AT SAID PYROLYSIS STATION WHILE HEATING THE SAME TO PYROLYTICALLY REACT THE SAMPLE, AND RETURNING SAID BOAT ALONG SAID PATHWAY TO SAID SAMPLE LOADING STATION TO COMPLETE ONE CYCLE.

5. A method as in claim 3 in which said boat is moved from said pyrolysis station to a cooling station interposed along said pathway between said pyrolysis station and sample loading station prior to movement to the latter station, the boat is held at said cooling station for a selected period of time sufficient to substantially decrease the temperature of the boat, and thereafter the boat is returned to said sample loading station.

7. Apparatus for conveying small samples of materials into a pyrolysis tube for subsequent analysis comprising: a. Frame means; b. A generally sealed loading tube mOunted on said frame means and connected at one end directly in communication with the pyrolysis tube to effectuate a continuation thereof; c. A sample boat slidably disposed in said loading tube, said boat having a cavity for receiving a sample to be analyzed; d. Loading means connected near the end opposite of said one end of said loading tube to conduct a sample of material into said boat at a sample loading station in said loading tube; e. Means connected to said boat for moving it through the loading tube into the pyrolysis tube; said moving means including: (1) a rod connected at one end to said boat, and (2) a reciprocative assembly, comprising a cylinder stationarily fixed relative to said frame and a piston attached to said rod and slidably disposed within said cylinder; f. Gas valve means in fluid communication with said cylinder to selectively position said piston at least at two predetermined positions therein, thereby to correspondingly position said boat at predetermined stations within said loading tube and the pyrolysis tube in response to gas pressure applied through said valve means against said piston, one of said stations being said loading station and another being a pyrolysis station.

12. Apparatus according to claim 11 including means in heat communications with said loading tube for heating said warming and pyrolysis stations to varying degrees and means for cooling the boat at said cooling station.

13. Apparatus according to claim 11 wherein said gas valve means includes two gas bleed valve means mounted in flow communication with respective spaced-apart locations in the interior of said cylinder intermediate its ends, said bleed valve means each being selectively and independently operable between an open and closed position for locating said boat at said warming and cooling stations within said loading tube.