US2099080A - Bottom hole well sampler - Google Patents

Description

Nov. 16, 1937. G. w. RusLER BOTTOM HOL WELL SAMPLER Filed April 8, 1936 5 Shee'bS-Shee'l'. 2

Nov. 16, 1937. G w, RUSLER '2,099,080

BOTTOM HOLE WELL SAMPLER Filed April 1938 5 she'zs-sneet 3 .D www Nov. 16, 1937. I I G. w RUSLER w 2,099 ,080 BoT'roM HOLE WELL SAMPLER Filed Aprfil 8. 1936 5 SheetS-Sheet 4 'III/47,

Nov. 16, 1937. G w RUSLER 2,099,080

BOTTOM HOLE WLL SAMPLER Filed April 8, 1938 5 sheets-sheet 5.

z 70a 77; 7 mi 2 .29 'a 30 v a "w" Patented Nov. 16, 1937 PATENT oFFics aosaoso Bo'r'roM HoLE wamJ sAMrLEn George W. Busler, Verona, Pa., assignor to Gulf Research & Development Company, Pittsburgh, \Pa., a corporation of Delaware Application April 87, 1936, Serial NO. 73,385

19 Claims.

This invention relates to bottom hole well samplers, and it comprises a tubular chamber adapted to be lowered into an oil well and provided at each end with valved units having outv wardly closing valves for entrapping fiuids in the chamber as they exist in their natural state in the well, valve Operating mechanism in the chamber for causing positive operation of the valves, said mechanism including an interlock for preventing operation of one of the valves until the other valve has closed and a dashpot for one or for each of the valves to soften the closing action of the valves; thus avoiding any pressure or volume disturbance of the fiuids in the chamber relative to the surrounding fluids in the well by the closure of the valves; and it also comprises means in the chamber for enabling measurement of the pressure of. the fiuid entrapped in the chamber without change in volume and means for automatically setting the valve interlock and the valves by simply assembling the Valve units to the chamber, one of said units being provided with cable supporting means and a trigger mechanism for Operating the valves and the other of said units being provided with a maximum recording thermometer, all 'as more fully hereinafter set forth and as claimed.

It is of importance to acquire accurate knowledge of the physical and chemical characteristics of fluids as they exist in various locations in a pool o rformation and as they exist in the flow string of Wells in order to solve problems relating to pumping efiiciency and the like and in order to predict with a fair degree of accuracy the changes the fiuids in the oil pool will undergo throughout the life of the well. It is particularly important to know the quantities and properties of the gas liberated from solution in the oil at various pressures in the formation and in the fiow strings of the wells. With such knowledge it is possible to attain high production emciency in the operation of wells drilled into a particular pool or formation. This knowledge is best obtained by determining the temperature of the fluids as they exist in the formation by lowering a maximum recording thermometer into the formation at different locations, by securing sample quantities of the fiuid from the formation and flow strings of Wells drilled into the formation as it exists in its natural state except for change in temperature, and by examining the samples so obtained after adjustment of their temperatures to that at which they existed in the formation or well string as recorded by the thermometer.

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(cl; rar- 18) To accomplish this purpose numerous forms of apparatus have been developed, adapted to be lowered into a well and entrap a sample of the fluid in the pool at the bottom of the well.

With all prior forms of apparatus of which applicant is aware, the sample of fiuid upon examination does not accurately duplicate the fluid in the well from which the sample is taken and therefore figures based upon the results of an examination of such sample fluids are unreliable. This is for the reason that the fiuid at the bottom of a well, because of its high pressure is in an extremely unstable condition. The gas to oil ratio is apt to change instantly upon Sudden jarring of the sample as by a simultaneous snapping shut of the valves of the sampler. Further dlfficulty has arisen in accurately determining the pressure of the fluid sample since this pressure must be taken without change in volume. This is because the fiuid entrapped is composed of both gas and liquid and frequently gas dissolved in liquids, and the gases under the conditions at which they exist do not necessarily obey the ideal gas laws as to pressure and volume.

A further disadvantage of many prior devices is that external valve control rods are troublesome both in assembling and disassembling the sample, and in catching on joints or obstructions in the well tubing during lowering and raising of the device in a well.

It is an object of the present invention to provide a sampling device which shall entrap a quantity of fluid at the bottom of a Well in exactly the same physical and chemical conditions as the fluid surrounding the device during entrapment, and which shall maintain the fluid so entrapped under the conditions existing in the well except for temperature changes.

A further object of the invention is the provision of a sampling device in which the valves to 'sampling chamber are positively closed and pressure or volume disturbance of the fluids during entrapment is reduced to a minimum. This is accomplished by the provision of an interlock in the valve Operating mechanism permitting one valve to close completely before the other, and the provision of a dashpot for one or both of thea valves to insure softness of the closing operation.

A further object of the invention is the provision of a valve Operating mechanism located entirely within .the sampler with the exception of the usual Operating trigger at the top of the sampler. and which mechanism automatically sets itself to open the valves upon mere assembling of the' sampler parts.l

A further object of the invention is the provision of means in the wall of the chamber in which .the fiuid is entrapped enabling measurement oflthe pressure of the contained fluid without change in its volume.

A further object of the invention is the pro vision of novel means for securing the sampler to the end of a cable after valves are set, said means also protecting the trigger from accidental operation during transportation of the instrument and during the act of fastening the endl of the cable thereto. w

A further object of the invention is the' provision of a well sampler which shall be inexpensive in manufacture, composed of a small number of parts arranged for unit assemblage and disassemblage and which shall be exceptlonally simple and accurate in operation.

Other objects and advantages of the invention will be apparent from the following detailed description read in connection with the accompanyw ing drawings, wherein, g

Fig. 1 is a longitudinal sectional view of the top or head portion of the sampler and shows the trigger mechanism and top valve assembly;

Fig. l-A is a longitudinal sectionsal view of the middle portion of the sampler and shows the valve interlock mechanism and the arrangement of the pressure diaphragm means for measuring pressure within the chamber;

Fig. l-B is a longitudinal sectional view of the bottom or lower end of the chamber and shows the arrangement of the lower valve and thermometer well; i

Fig. 2 is a'view of a. side elevation of a lubricator used in introducing and withdrawing the sampler from a well, and shows the samplerv in dotted lines;

Fig. 2-A is a Vertical sectional view of the messenger supporting and releasing mechanism for the lubricator.

Fig. 3 is 'an enlarged horizontal sectional view taken along line 3-3 of Fig. 1 in the direction of the arrows;

Fig. 4 -is an enlarged, fragmentary, detail sectional view of the trigger mechanism for closing the valves;

Fig. 5 is a detailed perspective view of the trigger;

Fig. 6 is a detailed perspective view of the trigger spring;

Fig. 7 is a detailed sectional view of the valve interlock showing' the position of the parts when the valves are in closed position;

Fig. 8 is a horizontal section view taken along line 8-8 of Fig. 7 in the direction of the arrows;

'Fig. 9 is an enlarged horizontal sectional view taken along line 9-9 of Fig. 1'-A in the direction of the arrows;

Fig. 10 is a reduced, detail longitudinal sectional view taken' along line lO-III of Fig. 9 in the direction of the arrows;

.Fig. 11. is a view similar to Fig. 10 but with the caep and diapln'agm of the pressure measuring means removed; v

Fig. 12 is an enlarged, detail sectlonal view showing the construction of the valves and valve seats; and

Fig. 13 is a Vertical section of a modified form of upper valve construction showing one arrangement for applying a dashpot to the valve.

Fig. 14 is a vertical sectional view of a modified form cable tie fo'r the instrument. f

Fig. 15 is a side elevation of the tie shown in Fig. 14 with the cap shown in vertical section.

Fig. 16 is a detail side elevation of the body of the tie shown in Figs. 14 and 15.

Fig. 17 is a side elevation of the member shown in Fig. 16 and Fig. 18 is a horizontal section taken along line IB-IB of Fig. 16 looking in the direction of the arrows.

Referring to the drawings wherein like numerals indicate corresponding parts throughout the several views, the numeral designates the sample receiving or collecting chamber of the instrument provided with upper and lower out-'- wardly closing valves 2 and 3 respectively. These valves are substantially identical in structure and operation, both being of the mushroorn type and consisting of valve stems 4 and 5 to which are secured double inverted, frustro conical shaped valve heads provided with annular knife edge4 projections 6 and for engaging soft aluminumshown. Valve seats 8 and 9, respectively, are held in positionagainst internal Shoulders H and l5 in members iii and |2 by the externally threaded ends ofvmembers I! and 13 engaging the internally threaded ends of members Ill and |2 as shown. Valve unit members H and |3 are provided with valve stem guides IB and l'l cast integrally therewith and supported by spiders (not explained.

The trigger mechanism for Operating the valves' is arranged as a unit on a base or bracket member 23 held in the head by machine screws 24. Projecting from the base are standards 25 extending downwardly to a point adjacent the end of valve stem 4. (Figs. 1 and 3.) The standards support a lever 26 pivotally connected thereto as at 21 and extending across the end of the valve stem. To hold the valve off its seat the lever is normally held against the end of the valve stem by the longer arm of a bell crank 28 which ispivotally carried as at 29 on the base' of the trigger mechanism. The short arm of the bell crank extends horizontally to a point beneath a -trigger .pin or plunger 30 passing through the head and projecting slightly above the top of the head. This pin is arranged for limited Vertical movement in the headby the provision of an enlarged portion 3| in counterbore 32. The counterbore is closed at its lower end .by a screw collar 33 through which the pin passes. A spring member 34 .secured to the trigger base by means of screws 35 engages through its arms 36 with transversely extending lugs 31 on each side of the end of the long arm of the bell crank to maintain the crank in engagement with lever 26 and hold valve 2 open. In this position the short arm 'of the bell crank engages the lower end of the trigger pin and forces the pin upward through the head of the instrument in position to be struck by a messenger 38 on cable 39 supporting the instrument. The sampler is secured to the end of the cable by passage of the cable through an openaoeaoeo mg m nie center of the head of the mammet where it is first bent slightly on -a large radius about a cam shaped member 40, to avoid creation 'of superimposed bending stresses in the cable.

Member 40 is held in the head of the instrument by a pin or screw 4| and has a small radius hub i portion (not shown) on which the cable is subseclamping under the head of the screw.

On the end of valve stem guide H for th lower valve `3, a combined dashpot 08 and thermometer well or housing M is secured as at 45. The dashpot is adapted to 'receive the lower end of valve stem 5 and contains a light coil spring 45 which engages the end of the valve stem to normally hold' the valve in open position. A small opening 41 in the bottom of the dashpot permits slow leakage of oil from the dashpot during closing of the valve. 4B is a tube containing a maximam recording thermometer held in housing 4d by screw cap 05. The thermometer may be read or observed through window 50 in the tubing after 4renit'ival from the housing. The lower end of the instrument including* the thermometer -well or housing is protected by a cap or foot piece 5| .which screws on the externally threaded end of valve unit. coupling member |3. This foot piece is open at its lower end as at 52 and provided with screens 53 held in position by castellated, externally threaded ring shape member 54. As so far described it will be seen that when the valves Z and 3 are open and the sampler submerged in fluid in .the well the well fluid may pass freely through the length of the entire instrument, enteringat the bottom through screens 53 and 'leaving at the top through screened openings zi.

The valves are forcibly closed by a mechanism hereinbefore referred to as the valve interlock,

located in the sample receiving chamber of the instrument. The interlock consists of push rods 55 and 56 arranged to slide, one within the other in a spider supported bearing member 51,' secured within the chamber about midway between the valves by means of screws 58. The opposite ends of the rods are carried in spider supported beara tubular extension or sleevelike member 56' which passes through bearing 51 and has fltted to its reduced end 51 against shoulder 58' a spring end retaining collar 69. The end of push rod 55 has a reduced portion 10 having a sliding fit within tubular extension 55 on push rod 55. Shoulder 1| formed on rod 55 by this reduced portion serves as a seat against which second spring end retaining collar 12 is seated and a coil spring 13 positioned between the collars tends to force the push rods apart or in opposite directions. The extreme end 14 of push rod 55 is still further reduced in diameter where it slides in that part of extension 66 in the bearing 51. In order that one of the push rods may -move to close its valve prior to closure of the other valve by the second push rod, the top end portion of bearing 51 is enlarged as at 15 ,and a series of vcircular openings 1| are provided in' sleeve 05 adiacent the enlarged portion of the bearing for reception of hardened steel balls 11. These balls are of greater diameter than the radial distance from reduced portion 10 to the outer surface'of sleeve 50 so 'that sleeve 6518 held against downward movement by jamming of the balls in the opening against tapered shoulders 10 formed in the bearing at the bottom of the recess. Howevel', push rod 55 may move upwardly to close top valve 2 and in so doing its reduced end portion 16 moves beneath the balls. Coil spring 13 then aots to force the balls through the openings 15 and against end 'll out of contact with the shoulder formedin the recess, thus permitting sleeve 05 to move downwardly carrying the balls with it to close lower valve 3. 19 is a small oil opening in -sleeve 0B for lubrication of the interlock and is a retaining washer fitting within enlarged opening 15.

Provision is made for measuring the pressure of the fluid entrapped in the sampler without changing its volume by permanently mounting a pressure diaphragm assembly in the chamber accessible from the loutside of the chamber through opening This diaphragm assembly consists the opening and secured to the wall of the chamber by screws 53. This joint is best sealed against leakage by soldering or welding or lthe like. Against the inner surface of opening 84 through the body member a pressure diaphragm 85 is clamped by means of a cap 86. Cap 86 is slightly relieved on its inner side opposite' the diaphragm as shown at 81 Vand is provided with perforations 88 for permitting the pressure of the fluid entrapped in the chamber to exert inself against the inner face of the diaphragm. On the inside of body member 02 and electrically insulated from it is a thimble 88 carrying contact screw 90 -for making electrical contact with the inner face of the diaphragm. This thimble is supported in porcelain 9| or other insulating material held in inside flange 02 on the body member perforated as at 03 to permit pressure to be applied exteriorly to the diaphragm. Access to the contact screw and to the diaphragm through perforations 00 is had by removing the screw lplug 94.

of a flanged body member 02 projecting through For the purpose of describing the operation of the sampler it will be supposed that the sampler has just been emptied of its contents, disassembled. cleaned, and the valve seats renewed. The valves are set lin open position' during assembly asfollows. The lower valve unit is first attached to the chamber i. Before attachment a blind cap is screwed to the end of valve stem guide |1 in place of the thermometer well M. so as to hold valve 3 clear of its soft aluminum seat and in its regular open position with respect to this seat. Durlng attachment of the lower valve unit to the chamber I the head of valve 3 strikes the lower end of push rod 55 and forces it upward against the action of spring 13 moving the balls 11 in the interlockopposite the enlarged opening 15 in the bearing 51. The upper valve unit with the trigger set as by depressing the plunger or trigger pin 30 with the finger and tilting the head so that lever 26 falls into position against the end of valve stem l, is 'then screwed on to the chamber. During attachment the head of valve 2 strikes the end of push rod 55 and forces it downward against the pressure of spring 13 and at the same time reduced end 10 on the push rod forces the balls 11 into the enlarged opening 15 of the bearing and holds them there thus the thermometer reset and placed in the well and the well attached to the valve guide in place of the cap. The lower end or foot piece of the instrument is then screwed on to the bottom valve unit. Next, theA diaphragm contact screw 90 is adiusted so that it just contacts the diaphragm when the diaphragm is in its neutral position. The cable-is then attached and the instrument lowered into a well, to the bottom thereof or to any point in the flow string at which it is desired to take a sample. At this point it may be advantageous to describe one form of apparatus, illustrated in Figs. 2 and 2-A of the drawings, useful in introducing the sampler into 'a well. This consists of a pipe 95 called a iubricatorwhich is adapted to be screwed to gate valve 90 at the casing head of a well. The lubricator is longer than the sampler and has a branch pipe 91 leading off from thelower end thereof with a pressure gage 90 and a throttie valve 99 mounted therein as shown. At the upper end of pipe 95 a pulley is supported on an'arm |0| carried by pipe 95. The end of the cable is guided over the pulley through a stuiilng box |02 and down through a messenger 103 concentricaliy support.- ed in the upper end of lubricator pipe by means of a guide block m rigidiy secured to the inside wall of the vlubricator by stud bolts |05. The messen'ger is releasabiy supported in clamping engagement with the guide member by means of hand wheel operated set screw |06. When desirable the messenger may be threaded on and.

off the cable by passing the cabie through a helical slotted opening |0`| in the side of the messenger. The end of the cable is secured to the sampler. The sampler is then drawn upward' into the iubricator and the lubricator screwed on to gate valve 90. This valve is then opened and the sampler lowered into the well. During low'- ering of the sampler in the wellI the vaives being open, well fluid caused by lowering of the sampler or by convection currents or ebullition of gas passes through the sampler. When the' desred location for the taking of a sample has vbeen reached the sampler is allowed to remain motioniess for a period of some 20 minutes or longer or until the surroundng and contained well fluid reaches a state of uniformity. When it is thought this stage has been reached. the messenger is released from the lubricator by operation of hand wheel 106 and slides down the cable striking the plunger 'or trigger Operating pin 30 to'release lever 26 from engagement with the bell crank or trigger and allow spring 13 to force valve 2 closed. piained releases the balis 'I'l in the interiock from the Shoulders 19 and allows the spring to close valve 3. Closure'of valve 3 however is: resisted by slow escape of oil from dashpot', through opening so that this valve closes slowly. The purpose of this is to provide an intervai of time Closure of valve 2 as exaooaoeo provided with a small opening [05 for slow escape of oil entrapped by the piston.

After both valves have been closed the sampler is withdrawn from the well, foot piece 5| removed, and the temperature of the well fluid 'at the point at which the sample was taken noted by reading the maximum thermometer.

The sampler is then heated to this temperature i and the pressure of the contained fluid measured by connecti'ng the body of the sampler and a volt meter in series in an electric circuit, through electrical contact screw 90 and diaphragm 05. External fluid pressure is then applied to the diaphragm through perforations 93 in body member 82 until the diaphragm is moved siightly to open the electric circuit or break its electrical contact with the contact screw as indicated by the Volt meter. The external fluid pressure recorded by a gauge in the pressure line at this instant will be substantially exactly equal to the pressure of the entrapped fluid provided the contact screw just contacts 'with the diaphragm and doesnot exercise pressure against the diaphragm to disto't it or is not spaced from the diaphragm so' that the diaphragm is distorted by the pressure of the entrapped fluid. Under these conditions lany difference in pressure between the making and breaking points of the circuit will be caused by the stiffness or rigidity of the diaphragm itself and with a suitable diaphragm will be so small as to be practically indiscernlble on the pressure gauge. This is so particularly in view of the fact that current fiowing in the circuit is verysmall and an almost imperceptible movement of the-'diaphragm serves abies unit construction of the sampler since it,

together with the spring. push rods and sampler body portion constitute a "motor" unit from which the valve units may be easily removed and separately assembled and disassembled. This greatly simplifies the construction and operation of the sampler and is important because of the necessity for renewing the soft metal valve seats each time the sampler is used.

In Figs. 14 to 18 inclusive, I have shown a modified form of cable tie which is particularly adapted for use with the sampler. Referring to these flgures the numeral |08 designates the head on the top end of the sampler in' which the trigger '30 is mounted as before described and to which cable 39 is secured. Head |08 is provided with an extended, externally threaded portion 109 to receive a protecting cap 0 for the tie. The protecting cap projects above the top of the' head and has an opening il'l therethrough for passage of the trigger and the cable. This opening is of considerably greater diameter than necessary to receive the cable and trigger but is of smaller diameter than the diameter of mess'enger |03.

The purpose of this large opening is to avoid swagging or burring of the metal close to the trigger by impact force of the messenger sent down the cable. Swagging or burring of the cap at this point would cause the trigger. to bind or stick. With the above construction the impact ,force of the messenger is absorbed almost entirely aoeaoeo by the. top of the cap since the trigger itself offers little resistance to the downward movement of messenger and any swagging or burring of the metal of vthe cap around opening Ill is remote from the trigger and cannot cause the trigger to bind or stick. A further advantageof this construction of tle is that the trigger and valves -of the instrument may be set in operative position some distance from the place where the instrument is to be used and before securing the instrument to the end of the cable, and the cap unscrewed partly or until it extends beyond the end of the trigger to shieid and .protect it from accidental operation. The sampler may be transported and handled in this condition without danger of accidental firing of the trigger. Immediately before using the sampler the cap is screwed down tight to expose the end of the trigger for striking by the messenger.

The tie itself is made in head-piece IBB and consists of a relatively large diameter hub member M2 about which the cable is wound for snubbing the line pull on the cable, an annular groove M3 encircling the head below the hub member for receiving the cable from the hub member and a set screw H for final fastening of. the end of the cable. The set screw and the hub member are positioned in a recess in the side of the head and the cable is passed downwardly to the hub member through an opening in a projection overhanging the recess as shown.` A pin ||5 eccentrically located in hub member U2 and passing into the head prevents the hub member from turning.

In this form of tie as in the construction of tie first described the line pull on the cable is first snubbed by winding the cable about a large radius hub in a plane passing through the length of the cable above the ti`e 'and then is further snubbed by passing the cable around the head in the annular groove so that little or no line pull'remains to loosen the final clamping at the set screw or fracture the cable where it bends sharply around the screw.

What I claim is:-

1. A well sampler comprising a tubular casing, a valve in said casing adjacent each end thereof, said valves forming a sealed chamber with the casing when closed, closure. means in the chamber for each of said valves, means positioned in the casing for releasably holding the valves in open position, and means in the chamber operable by a predetermined movement of one of said 'valves for Operating the closure means for the other of said valves.

2. A well, sampler comprising a tubular casing, valves adjacent each end of said casing,saidvaives forming a chamber with the casing when closed,

closure means in said chamber for each of said valves, means in the casing for releasabiy holding the valves in open position, and means in the chamber operable by a predetermined movement of the closuremeans for one of said valves 'for operating the closure means for the other of said valves.

3. A well sampler comprising a .tubular casing, a valve in said casing near each end thereof, push rods in said casing for Operating the valves, each of said push rods being normally fixed against movement, means for actuating the push rods upon their release, means in the casing for releasing one of said push rods and means in the casing operable by a predetermined movement of said released push rod for releasing the other of said push rods, whereby the push rod actuating means is effective to operate one push rod subsequent to a predetermined movement of the other push rod.

4. A well sampler comprising a casing, a portion thereof forming a chamber for the collection of samples, a valve seat at each end of said chamber and valves for'said valve seats, push rods in the chamber for seating the valves, the push rods being normally fixed against movement, means for operating the push rods upon their release. the push rods being associated with each other in sliding arrangement, means for releasing one push rod to' permit the push rod operating means to move it a predetermined distance with respect to the other .rod and means associated with the two rods for eifecting release of the other rod upon said predetermined movement, whereby the push rod operating means will then operate to move both push rods to permit them to firmly seat the valves.

5. A well sampler comprising a tubular casing, a valve in said casing near each end thereof, said' valves defining a chamber in the casing, push rods in said chamber for closing the valves, said push rods being movable .in opposite directions to close the valves, adjacent ends of the push rods being in telescoping engagement, a collar disposed on the endv of each push rod, a spring on said push rds adapted to be compressed between said collars to move the push rods in opvposite directions and means in the chamber operable by a' predetermined movement of one of said push rods for releasing th'e other of said' push rods for movement by the spring.

6. A well sampler comprising/a tubular member open at its ends, a valve near each end of said member, said valves when closed being.

'the valves until the other valve has closed.

7. A well sampler comprising a tubular casing, a pair of oppositely disposed vvalves in said casing spaced apart to provide a chamber therebetween, push rods for closing the valves, a stationary guide for said push rods, the ends of said push rods being slidable one on the other 'in said guide,

shoulders on each of said push rods, a spring on said push rods' adapted to be compressed between said shoulders, said spring tending to force the push rods in opposite directions to close the valves, a recess in said guide, a key in one of said push rods'adapted to engage the guide at said recess to prevent movement temporarily of ;said push rod with respect to the guide, and a cut away portion adjacent the end of the other push rod adapted to receive said key upon movement of said rod a predetermined distance, whereby upon such movement the key will leave the recess in the guide and enter the cut away portion on the other push rod and both rods will be free to move under pressure of the spring in opposite directions to close the valves.

8. A well sampler comprising a tubular casing, upper and lower oppositely disposed valves in said casing spaced apart to provide a chamber therebetween, upper and lower push rods in said chamber for closing said valves respectively, 'a stationary guide in said chamber for said push rods the ends of said push rods being in telescoping engagement, the upper within the lower, in

'said guide, shoulders on said push rods, a coil spring on said push rods adapted to be compressed between said shoulders, said spring tending to force the push rods in opposite directions to close the valves, a cylindrical -recess 'in said by the lower` push rod is held from moving to close the lower valve until the upper` push rod has moved a predetermined dlstance to close the upper valve.

9. A well sampler comprising a tubular casing, valve assembly units adapted for attachment .to

the ends of said casing, valves and valve seats' in said' units adapted to form a sealed chamber with. said casing when the valves are closed,

means positioned in one of said valve assembly units for'releasably' holding the valve in said unit ofl its seat, means for resiliently holding the valve in the other unit oif its seat. spring motor means in said chamber for closing said vvalves and means in said chamber operable by apredetermined movement of one of said .valves for operating the spring motor ciosure 'means for the other of said valves.

'10. In combination, a well sampler whereln a sample of well fluid is entrapped under pressure within a valve chamber and means permanently associated with said chamber for determining the pressure of the fluid entrapped therein, said means comprising a pressure-responsive diaphragm in the wall of said chamber, one side of said diaphragm being exposed to fluid :pressure within the chamber, an electric contact screw adjustable with respect to said diaphragm to contact therewith, and means for applying external pressure to the other side of said diaphragm tobreak its 'electrical contact with said screw whereby the 'external pressure required to break said 'contact is substantially equal to the pressure of the contained sample of well fluid.

11. In an instrument designed for actuatlon subsequent to its being .positione'di in place and arranged to be suspended in place by means of a cable attached thereto and having trigger mechanism operated by means of a messenger sent alongthe cable, a protecting cap and 'messenger stop for said instrument having an opening of less idiameter than the diameter of the messenger through which the cable extends and through which the trigger projects when set, the

'opening being of sufilcient size to' accommodate' both the cable and the trigger and to leave room between them 'and its edge whereby the messenger may strike the trigger to operate it and then expend its surplus impact force against the cap and any burring of the top or edges of the cap duel to impact with the messenger will not interfere with'the operation of the trigger.

12. In an instrument adapted to be suspended at the end of the cable and provided with a trigger projecting therefrom and adapted to be operated by a weight sent down the cable, a protecting device for said trigger having an opening through which the trigger passes and means for moving the protecting device on said instrument with respect to the set position of the trigger to expose it above said opening when the instrument is in position for operation by the messenger and to conceal it beneath said opening to guard it against accidental operation when the instrument is not in position for operation.

. 13. An instrument to be suspended in the well or the like by means of a'cable and having trigger mechanism operable by a messenger sent down the cable when the instrument is in position.. a guard member threaded to the instrument and having an opening at the top through which the trigger and the cable pass, the threaded connection between the instrument and said guard member being such as to permit extension of the guard member above the top of the trigger to prevent accidental manipulation uthereof until the instrument is ready for use.

14. A-well sampler comprisin'g a tubular casing, valve assembly units adapted for attachment to the ends of said casing, valve and valve seats in said units adapted to form a sealed chamber ,2

with 4 said casing when the valves are closed, means positioned in one of `said'valve assembly units for releasably holding the valve in said unit. off its seat, means for releasably holding the valve in the other unit off its seat, spring motor means in said chamber for closing said valves and means in said chamber operable by a predetermined movement of one of said valves for operating the spring motor means for closing the other valve.

15. A well sampler'comprising a tubular casing, a valve in said casing adiacent each end thereof, said 'valves being adapted to form a sealed chamber therebetween when closed. valve tripping mechanism in said casing for one of said valves, valve tripping mechanism in said chamber for the other of said valves and means convne'cting said valve trippin'g mechanisms so that upon actuation of one of said mechanisms to trip ,its valve, the other mechanism is caused to act to trip its valve, and means for closingsaid valves after release by said tripping mechanisms.

16. A well sampler comprising a' tubular cssingj a valve in said casing near each end thereof, said valves defining a chamber with the casing when closed, push rods for closing the valves, said push rods being movable in opposite directions to close the valves, adjacent ends of the push rods being 'in telescoping engagement, a collar disposed on each push rod near the ends thereof, a spring on said push rods adapted to be 'compressed between the collars to move the push rods in opposite directions, means for holding said push rods in retracted position to compress the spring and means operable by a predetermined protracted movement of one of said push rods for releasing the other push rod for movement by the spring.

17. A well sampler comprising a tubular casing, a valve in said casing near each end thereof, said valves deflning a chamber with the casing for entrapment of a sample of well fluid, rods for each of said valves adapted for movement of the valves to closed position and means, releasable upon a predetermined movement of one of the rods, for holding the other rod motionless during said predetermined movement of the first named rod whereby said second rod is released to close its valve 'subsequentiy to the ciosure of the other valve by the first rod.

18. In a well sampler having a chamber adapted to receive a sample of well fluid and valves at each end of said chamber for entrapment of well fiuid in the chamber, means for holding the valves in open position and means for positively p s,ooo,o8o 7. whereby one of the members is held inv inoperative position until the other member has moved a predetermined distance to close its valve.

19. In a well samplerhaving a chamber adapted to receive a sample of well fiuid and valves at each end of the chamber for entrapment of well fluid inthe chamber, means for holding the valves in open position and means for positiveiy closing' the valves, said latter meam comprising a'closure member for each of the valves and means connecting said members whereby one o! the members is held ininoperative position until the other member has moved a predeter- 5 mined distance to close its valve.

` GEORGE w. Rusi-ER.

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