US2534489A - Automatic sampler of liquid and gas phase streams - Google Patents

Description

Dec. 19, 1950 L. A. WEBBER ETAL AUTOMATIC SAMPLER OF LIQUID AND GAS PHASE STREAMS Filed July 2, 1945 3 Sheets-Sheet 1 S W WM R O INVENTORS L..A.WEBBER O.W.KIPHART ATI' Dec. 19, 1950 L. A. WEBBER ETAL AUTOMATIC SAMPLER OF LIQUID AND GAS PHASE STREAMS s Sheets Sh eet 2 Filed July 2, 1945 INVENTORS L ANVEBBE R QWNPHART ATTORN 5 Dec. 19, 1950 A. WEBBER ETAL AUTOMATIC SAMPLER 0F LIQUID AND GAS PHASE STREAMS 3 Sheets-Sheet 3 Filed July 2, 1945 INVENTORS L AWEBBER ATTORNE Patented Dec. 19, 1950 AUTOMATIC SAMPLER OF LIQUID AND GAS PHASE STREAMS Ludwig A. Webber and Otta W. Kiphart, Borger, Ten, asslgnors to Phillips Petroleum Company, a corporation Delaware Application July 2, 1945, Serial N 0. 602,818

7 Claims.

This invention relates to sampling devices. In one of its more specific aspects, it relates to devices and methods for sampling of fluids. The design and construction of automatically operated equipment for sampling of fluids has yielded heretofore relatively costly and usually rather cumbersome and awkwardly operating equipment. We have found that the principle involved according to our invention may be applied to sampling devices for use in the composite sampling of either gaseous or liquid streams. Our. invention has special application in the petroleum industry but may be used as well in chemical or other industries where liquids or gases are to be sampled, compositely, over periods of time.

One object of our invention is to provide apparatus and a method for sampling of streams of fluids while in transit.

Another'object of our invention is to provide a method and apparatus which may be used for the taking of composite samples of either liquids or gases over rather long periods of time.

Still another object of our invention is to provide an apparatus for the composite sampling of gas streams at pressures less than atmospheric.

Still another object of our invention is to provide an apparatus for the composite sampling of gas streams at pressures greater than atmospheric pressures.

These and other objects and advantages will beapparent to those skilled in the art upon reference to the following detailed description and annexed drawing which respectively describes and illustrates preferred embodiments of our invention, and wherein Figure 1 illustrates an embodiment of our invention adapted for the sampling of hydrocarbon liquids which vaporize upon release of pressure.

Figure 2 illustrates an embodiment of our invention adapted for sampling streams of noncondensible gases or normally liquid streams under pressures greater than atmospheric.

Figure 3 illustrates an embodiment of our invention adapted for sampling streams of gases or liquids at pressures less than atmospheric pressure,

Referring to the drawing and specifically to Figure 1 numerals ll, l2 and I3 refer to motor air pressure. The flexible diaphragms H; are attached in conventional manner to valve stems l I and by movement of the diaphragm members the valve stems and accordingly the needle closure portions l4 are opened or closed. These valves may be spring loaded, as by springs :5. As shown in the drawing, each spring l8 serves as a tension spring and is so adjusted as to hold the valve needle in a normally closed position. Upon application of instrument air pressure to the under side of the diaphragms, the valve stems H are raised to open the valves to the flow of fluid, the springs l8 being accordingly subjected" to somewhat greater tensions. When the instrument air pressure is released, the normal tension of the springs moves the valve needles into their normally closed position.

A proportioning chamber I9 is inserted to connect motor valves H, I! and I 3 as illustrated in Figure 1. This proportioning chamber may be a standard pipe or copper tube T-fitting provided its inside or passageway volume is the volume required for the taking of predetermined size samples. Connections H which connect this proportioning chamber to the respective motor valves H and I2 should be as short as possible and of as small a bore as is practical with the desired sturdiness of construction. A tube 24 is attached to the outlet end of motor valve 12 to direct disposal of material not desired as sample.

A tube 22 connects the side arm outlet of the proportioning member IE to the motor valve l3. From the delivery side of this latter valve is a sample tube 23 for conducting the sample from the sample taking apparatus to a sample container, not shown.

Atiming apparatus 25 such as a time cycle controller is shown as a means for controlling the several motor valves according to predetermined time intervals. While this time cycle controller may be any type orkind of controller desired, it is obviously only necessary that it be capable of performing the desired operations in a satisfactory manner. By this, we mean that the controller may be electrically operated or it may be operated by a spring operated clock mechanism. A particular time cycle controller which we have used and found to be entirely satisfactory is one.

manufactured by the Hanlon Waters Company, and is mentioned herein merely as an example. The time cycle controller which we have used operates on a six hour cycle, but by repeating the six'hour cycle as many times as desired a composite sample of any desired size or over any desired period of time may be taken.

Time cycle controllers, such as the one mentioned above, operate according to pins, placed in holes around the circumference of a rotating plate. Thus by inserting pins into these holes over certain time intervals said pins, upon rotation of the plate, cooperate with other mechanism of the controller to permit flow of instrument air to such control apparatus'as the air operated motor valves l2 and I3. Such time cycle controllers as the one hereinabove mentioned are standard industrial equipment and may be purchased from equipment dealers or directly from instrument manufacturers.

Instrument air from an air supply, not shown, comes by way of a line 21 and passes through an air pressure reducer or regulator 26 to reduce the air pressure to that required for operation of such motor valves. This regulator 26 also contains a strainer element for elimination of foreign material from the air previous to entrance into the cycle controller. Said cycle controller contains valves for transmitting air pressure from the inlet air line 21 to air control lines 28 and 29 and for closing H and exhausting air pressure from said line 28 and 29.

Since motor valves II and I2 are intended to operate simultaneously, they are operated off the same air line 29 by running branch air lines 3| and 32 to said motor valves. Line 28 admits air only to motor valve l3. As shown in Figure 1,

these several air service lines transmit air pressure to the under side of the motor valve diaphragm members l6 so that an increase of instrument air pressure on the underside of said diaphragms will operate to raise the diaphragms and piped to the upper side of the diaphragms and.

operate to close the valves by compression of the springs I8.

In the operation of the modification of our invention shown in Figure 1 for th sampling of a liquid hydrocarbon, such as butane, which will completely vaporize at atmospheric pressure, the liquid hydrocarbon comes from its transfer line through a small diameter sample line and enters motor valve H. For taking a sample of butane the time cycle controller clock operates to admit instrument air from air line 21 to air line 29 and thence into the two branch air lines 3| and 32. From these branch lines the air pressure is transmitted to the diaphragms of valve motors (I I. and I2) which motors respond by opening their respective valves. Liquid butane then flows from line 20 through motor valve ll, tubes 2| and the proportioning chamber I9, mofor valve l2 and through bleed ofl. line 24 to such disposal as desired. The control clock holds these valves open for such a predetermined time as is thought necessary to flush out thoroughly any residual material, of course motor valve I2 remaining closed. When such flushing is complete, the cycle clock operates to permit closing of the valves H and i2 and accordingly there is re-.

tained in the proportioning chamber and connecting elements a measured volume of liquid butane.

Finally, the cycle controller admits air pressure by way of tube 22 to the motor valv II to open said valve. The liquid butane in the proportioning chamber then vaporizes and t e p s 1 obtained t e volume or chamber II by difference.

.4 pass through the valve l3 and are led to a sample collecting device 32. We have found that the sample vapors may be collected by displacement of brine from a container 34, as say, a 5-gallon bottle. Other liquids may be used for displacement purposes but we prefer to use a salt water brine since hydrocarbon gases are relatively insoluble in such a solution. In case a larger sample than 5 gallons is desired it is, of course, only necessary to use a larger bottle, and vice versa if a smaller sample is desired.

Several conditions of apparatus and operation may be varied for taking various sizes of samples, etc. For example, for taking a 24-hour composite sample of butane, the concentration of which does not vary appreciably, a sample each hour over said period might be suilicient. However, in case the composition of a stream being sampled varies considerably from time to time, it might be necessary to take composite samples each 15 minutes or each half hour in order to obtain a true average of a 24-hour run. To vary the periods of sampling it is only necessary to insert pins in the rotating disc of the time cycle controller at the proper time points, that is, for 15 minute, 30 minute or 1 hour operation. We have used a 6-hour time cycle controller for taking samples of butane each 15 minutes over a 24 hour period, thereby making the 24-hour sample a composite of 96 individual samples. The pins in the rotating disc are so inserted as to permit valves II and I2 to remain open for about one minute, during which time the previous sample is well flushed from line 20, valves II and I2 and the connecting parts. Valves II and I2 then close and valve It opens and remains open for about 5 minutes which time has been found ample for complete vaporization of the sample from the proportioning chamber l9 and transfer of the vaporized sample into the sample collecting bottle 34. At the end of such period valve i3 closes and the sampling apparatus then awaits th next sampling time as determined by the time cycle controller 25.

One of the critical points in our apparatus 01' Figure 1 is the volume of the proportioning chamher It and connecting parts. In case the volume or this chamber I! were too large, then a 5-gallon sample bottle might become filled with butane vapors with two or three samples instead of 24 hourly samples over a 1-day operating period. The eilective volume to be considered from this point of view is the total volume of the propertioning chamber portion of the apparatus and this includes the volumes of all members from the needle I4 in motor valve tube 2|, chamber I9, tube 2| (extended), to the needle I 4 in motor valve l2, and tube 22 to the needle H in motor valve l3. Thus, twenty-four times this total volume of liquid when vaporized will be the volume or the gas sample collected. In order to collect a composite gas sample of reasonable size, say five'or ten gallons. this total volume must be relatively small as will be obvious to a chemist. For this reason, we prefer to use small bore tubing for tubes 2| and 22 and these tubes should be as short as practical. In addition, the diameter oi the hydrocarbon conduit through said motor valves must be relatively small. In making our apparatus of Figure 1, we determined by calculation the total liquid butane volume re- 4 quired for this proportioning chamber portion" or the apparatus, and knowing the volumes or the 7 motor valve conduits, tubes 2| and 22, then we asscaao This procedure will need to be followed for making our apparatus for sampling such hydrocarbons as butane, isobutane, the butenes. etc. taking into consideration the volume of composite sample to be taken, the total time period over which the sample is to be taken, and the frequency for taking the individual sample fractions.

" We have found that once an apparatus of this character is properly constructed that it requires no man power for operation and all the time needed is that required for changing sample bottles.

The apparatus may well be housed within a box or other container for protection. However, the brine tank and sample bottle need not be completely housed but may be arranged under a roof to aflord protection against such elements as rain, hail, snow, etc.

The embodiment of our invention illustrated in Figure 2 of the drawing is adapted to sampling of noncondensible gases under pressure. The principles and main points of operation are similar to those above described in relation 'to use of 1 apparatus of Figure .1. In the device of Figure 2. gas under pressure and to be sampled comes from a vessel to be sampled by way of a line 4|,passes through a motor valve 42, and through a connecting tube 43 into a proportioning chamber 44. From this reservoir or proportioni'ng. chamber 44 the sample of gas passes through a connecting tube 45, a second motor valve 46, through a transfer tube 41 and thence into a sample bottle 48. As sample gas passes into the sample bottle, liquid which for our purpose may be a brine solution, is displaced and flows into a brine tank 50, the level "or the brine solution being indicated by reference numeral 49. Instrument air from a source, not shown, comes through an air line 52,

sure gages 54, 56 and 59 indicate the instrument air pressures in these respective control lines. The motor valves 42 and 46 may well be of the same type as those described in relation to Figure 1 and contain valve needles 63 and 64, and tension springs 65 and 66.

In the operation of this embodiment of our invention, the time cycle controller is set to operate at quarter hour, half hour, or hour intervals as desired. Instrument air from line 52 passes through the cycle controller 55, air line 56 to the under side of diaphragm 60. Air pressure at this point opens the valve needle 63 against the tension of spring 65. Under these conditions gas to be sampled under pressure flows from line 4| into the proportioning chamber 44, of'course, motor valve 46 remaining closed.

Valve 42 remains open for a sutlicient period of time to permit pressure in the proportioning chamber 44 to become equal to that in sample line 4i. This period of time, however, is relatively short since the volume of the proportioning chamber is rather small. The valve, however, is usually set to remain open the minimum length of time obtainable on the specific cycle controller used. When the proportioning chamber is fully pressured, then valve 42 closes, and valve 46 then opens and permits expansion and flow of the exthe mercury reservoir 83.

panded gas through the valve and sample tube v in this condition until time for taking another sample.

The critical point in this particular gas sampling apparatus (of Figure 2) is the size of the proportioning chamber 44. The size or volume of this chamber should be such that for sampling a gaseous material under a certain pressure, that the required number of time spaced-individual samples will not yield a composite sample of volume greater than the volume of the sample bot tle 48. It will be obvious that the greater the pressure of the gas bein sampled, and the greater the number of samples taken over a period of time, the smaller the sample chamber may be. For utility of sampling apparatus, we have found it advisable to make provision for the proportioning chamber to be removable from the apparatus so that various size chambers may be inserted depending upon sample requirements.

The apparatus shown, diagrammatically, in Figure 3 is intended for sampling gas streams or normally liquid hydrocarbons at slight vacuum or at a pressure too low to displace brine from a sample bottle. This apparatus is similar in many respects to those of Figures 1 and 2, but differs mainly in that a Toepler pump is used as a means for transfer of the gas from the process line under slight vacuum to a sample bottle under atmospheric pressure.

Referring to the Figure 3, instrument air from an air line lfl'passes through a time cycle controller mechanism TI and thence through lines 12 'and'iil. This time cycle controller may be similar to those described hereinbefore or any other type desired, provided it is suitable for the purpose at hand. Four motor valves, 15, 16, I1 and 16, are also similar to those mentioned in relation to Figures 1 and 2. A Toepler type mercury pump 82 is used as the actual means for transferring the sample of gas from the process line, not shown, through sample tubes 89 and 90 into a gas sample bottle 9|. This pump consists essentially of a mercury reservoir 83, a sample tube 84 and a mercury transfer tube 94. The top of the sample tube portion of the pump has an outlet for connection to a tube 86; the mercury reservoir is provided with an opening for connection to a pipe 85.

In the operation of this embodiment of our invention (Figure 3), the time cycle controller operates to admit instrument air from pipe 10 to tube 19 and thence to tube and the diaphragm of. motor valve 16, and to tube 8! and the diaphragm of motor valve 18. These two motor valves then are forced open against the tension of their respective tension springs. With valve 16 open, air from another source under about 10 pounds per square inch gage pressure enters through air line 81, passes through the valve 16, pipe and into the upper portion of This air pressure forces the mercury from the reservoir 83 through tube 94 into the sample tube 84 to displace a sample of gas previously taken, forcing it through tube 86, motor valve 18 and sample tube 90 into the sample bottle 9| thereby displacing an equivalent quantity of the brine solution.

The height to which the mercury rises in the 3 sample tube 84 may be controlled by the pressure of the air entering through tube 88 or by a1 float valve mechanism so arranged as to pre- .vent the mercury from rising from the sample 1 tube 84 into the sample outlet tube 95.

;: -After the mercury has completely expelled all sample gas from I tube 84, the air pressure is r maintained on themeroury in vessel 83 until the time cycle controller operates to close motor 1 v valves:'|8 and I8. Following the closing of these two valves the cycle controller then operates to open valves 15 and 11. The opening of valve 15 releases the air pressure from the mercury reservoir by way of air lines 85 and 88, while the opening of valve 'I'l opens up the sample line to the hydrocarbon or other gas being sampled. Accordingly the release of air pressure from the reservoir 83 permits the mercury to flow from sample chamber 84 to the vessel 83 while at the same time sample chamber 84 is being filled with sample gas from tubes 86 and 88. After. passage of suflicient time for the sample tube 90 to displace a small volume of brine from the sample container 9|. operation completes an individual cycle.

Time cycle controllers such as the Hanlon Waters time cycle controllers, which we have This last sampling used and which we mention by Way of example,

are standard equipment and may be purchased from instrument manufacturers or dealers. Many different kinds and types of such equipment are on the market and. a user may use his judgment in selecting the one most suitable for the problem at hand.

The cycle controller to be used in conjunction with our sampling apparatus should be easily adjustable for the particular sampling conditions and should permit some of the operational steps to take place rapidly to prevent air leakage, or loss of or contamination of sample, while other operational steps should be of relatively long duration. These latter steps are necessary to permit passage oil sufficient time in order to be able to take samples at such intervals as to 1 hour. In addition, in case it is desired to take samples at short intervals, say from 5 to minutes, the controllers should be so adaptable. As mentioned hereinbefore, an operator may select from among many controllers since there are rather large numbers on the market.

When using the embodiment of Figure 3 for sampling normally. liquid hydrocarbons, it is usually not necessary to take as large a sample as five gallons even over a 24-hour period and accordingly a smaller sample bottle may be used. The sample chamber 84 for this service will then be made of size as to give a. desired volume of composite sample over a desired period of time.

In like manner, the motor valves for use in our sampling apparatus may be selected from among many types of motor valves listed in manufacturers catalogues. Among the many kinds or types of valves available we have found that needle valves are quite satisfactory. However, we do not wish to limit our invention in any way to the use of needle valves since other valves are satisfactory as, for example, plug type valves. We have found, however, that when using needle valves in conjunction with fluid operated diaphragm motors that we can construct a sampling apparatus for a very reasonable cost as compared to costs when using other valves with the necessary operating and control equipment.

In relation to the embodiment of our invention illustrated by Figure 1 wherein a liquid sample is withdrawn, allowed to vaporize, then passed to a-sample container as a gas. the volume of liquid involved is of importance. If, for example, a fivegallon sampleof butane vapor is desired as a composite sample to be representative of a 24- hour period of operation, and the five-gallon sample is to be made up of 48 individual samples taken at minute intervals, it is obvious that each of the 48 individual samples must be relativel small. By calculation, based on a liquid density of butane as 0.6, then 5 cubic inches of liquid butane will vaporize to give iive gallons of butane vapor at 32 F. and 1 atmosphere pressure. Each half hour sample should be approximately 0.1 cubic inch of liquid butane. Based on this reasoning, it is obvious that the volume of one individual sample of butane taken by the apparatus (Figure 1) will be the volume between the seats of motor valves ll, l2 and I3, which volume includes one-half the fluid passageway in each of these valves, tubes 2| and 22, and proportioning chamber-l8. Thus the summation 01 these several volumes should be approximately 0.1 cubic inch in order that 48 individual samples will give about 5 gallons vapor. In making up an apparatus of this embodiment, it is then necessary to use motor valves having very small diameter fluid passageways, connecting tubes 2| and 22 should also be small diameter copper tubing, for example, while the total volume may be adjusted by selection of a proper volume of the proportioning chamber l8. Such small diameter materials, as tubing and the like, are readily available, while small size motor valves might need have their fluid passageway diameter made smaller. In one instance,we have filled the passageways in 4 inch motor valves with lead then'drilled out a small diameter passageway on the liquid sample side of the needle.

For the embodiments of our invention illustrated by Figures 2 and 3, no special small volume apparatus is required since gases are being sampled and the samples retained as gas in each case.

The individual parts of each of the three samplers are relatively small, and we have found that each sampler can be assembled on a wooden or metal base approximately 2 feet square and the base setinto a housing having a side hinged door. The brine tank and sample bottle may best be disposed outside and adjacent the apparatus box.

In the embodiment of Figure 3 for sampling gases at less than atmospheric pressure, care must be taken that the mercury from vessel 83 is not forced over the top of sample vessel 84. As mentioned hereinbefore, this point may be controlled by maintaining a certain maximum air pressure on the air in air line 81, and for each maximum pressure there will be a certain and fixed height to which the mercury will be forced as measured by the difference in mercury levels in vessels 83 and 84. For example, 15 pounds will call for the X distance in Figure 3 to be about 30.6 inches, while 10 pound air will decrease this from air inlet pipe 81 can be depended upon not to exceed certain pressures, a check valve will not be needed in the outlet tube 95. We would. however, recommend installation of such a valve in all installations as a matter of safety to assist in preventing loss of mercury.

In all cases, the volume of mercury in the reservoir 83 must cover the open outlet end of the tube 94 to prevent passage 01" air into the sample tube 84 with subsequent contamination of sample in the bottle 9|.

Also, as mentioned hereinbefore, the sampling intervals, etc. may be changed at will merely by changing adjustments in the time cycle controller, and such adjustments" are well understood by those who operate such equipment.

Materials of construction may be selected from among those commercially available and suitable for the particular purpose at hand. If non-corrosive and chemically inactive gases are being sampled, ordinary materials may be used. If, however, sampling of corrosive gases is to be done, materials of construction should be resistant to such corrosion. v

In relation to the motor valves, we have found that the metal type diaphragms work well in these small valve motors. If other kinds of diaphragms are found suitable, they may be used in place of those which we mention. Even stopcock type valves may be used, but since these require electric motors for opening and closing, and complicated relays and wiring, we have found our air-operated samplers as herein disclosed are by far the least expensive to construct, and are simple and efllcient to operate and are essentiallv fool-proof, that is, they have operated for long periods of time without exhibiting mechanical difliculties or troubles. It will be obvious to those skilled in the art that many alterations and. modifications of our samplers may be made and yet remain within the intended spirit and scope of our invention.

What we claim is: i

1. A fluid sampling system comprising in combination at least two valves connected by a pro:- portioning chamber and providing fluid flow therethrough; a fluid sample inlet conduit connected to the open end of one of said valves; a gas sample collector vessel; a gas sample outlet conduit extending from the tree end or one of said valves to said gas sample collector vessel; fluid actuated valve operating means in each .said valve; conduit means extending between a source of pressurized-fluid and said valve operating means; and a controller in said conduit means, adapted to control the flow or said pressurized-fluid to said valve actuating means so as to alternately actuate said valve in the inlet to said proportioning chamber and said valve in the outlet end or said chamber.

2. The fluid sampling system of claim 1, wherein a third valve is connected to said proportioning chamber; agas vent conduit is connected to the tree end or said valve; and pressurized- 10 fluid conduits connect the actuating means or said third valve and said valve in the inlet to said proportioning chamber to the same source of pressurized-fluid from said controller.

3. The fluid sampling system of claim 1, wherein one pressurized-fluid conduit extends between said controller and said actuating means of the valve in the inlet of said proportioning chamber; and a second pressurized-fluid conduit extends between said controller and said valve actuating means in the valve in the outlet of said proportioning chamber.

4. The fluid sampling system of claim 3, wherein a pressurized-fluid actuated gas pump is provided in said proportioning chamber; and a third pressurized-fluid conduit extends between said pump and the same source of pressurized-fluid from said controller as said second pressurizedfluid conduit.

5. A fluid sampling system for sampling gas at atmospheric to slightly below atmospheric pressure comprising in combination a proportioning chamber having an inlet and an outlet; a first motor valve in said inlet of said proportioning chamber; a second motor valve in said outlet of said proportioning chamber; a

gas sample collector vessel; a first fluid conduit connecting said second motor valve and said gas sample collector vessel; a mercury displacement fluid pump connected to said proportioning chamber; a pressurizing system for said fluid pump comprising a pressurized-fluid conduit connecting a pressurized-fluid source and said fluid pump, and at least one motor valve in said pressurized-fluid line; and means for operating said motor valves.

6. The fluid sampling system of claim 5, where-v in a time cycle controller is in operational com munication with said means for operating said motor valves.

'7. The fluid sampling system of claim 5, wherein a second fluid conduit connects a constant pressure compressed air source and an air flow time cycle controller; and said air flow controller is connected to said motor valves by additional fluid conduits.

. LUDWIG A. WEBBER.

O'I'I'A W. KIPHART.

REFERENCES cr'ran The following references are 01' record in the file of this patent:

UNITED STATES PATENTS McPherson and Henderson publication entitled Course in General Chemistry, 2nd ed.; published by Ginn 8: Cg, Boston, Mass., pp. 44 to 46.

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