US2373034A - Well control device - Google Patents

Description

5 Sheets-Sheet 5 APH] 3, 1945- H. c. LAIRD Erm.

WELL CONTROL DEVICE Filed Sept. 5. 1941 Patented 'pr, 3, 1945 une WELL CONTROL DEVICE Hubert C. Laird and Herbert C. Otis, Dallas, Tex.; said Laird assignor to'said Otis Application September 5, 1941, Serial No. 409,668

1o claim (ci. .isc- 2) This invention relates to new and useful improvements in' well control devices.

It is an important object of. the invention to provide an improved control device adapted for use in a well flow conductor and which has means arranged to be actuated by the flowing well iiuids to automatically shut oi ow through the conductor when such owing well uid has created a pressure differential across the device in excess of a predetermined value.'

Another object of the invention -is to provide' an'improveddevice for controlling the flow of well iiuids through a iiow conductor wherein the well fluids are directed through a flow passage provided in said device, the device having a movable valve element exposed to the well fluids and means for restricting the ow of fluids through the device so that a -iluid pressure diierential scribed, means for'transferring the point of application of the iluid pressure diierential from one area of the movable valve element to another is set up across the valve element to actuate the same, said element being arranged to be actuated by a predetermined uld pressure diierential to close off flow through the conductor. Y

A further object of the invention is to provide, in a device of the character described, resilient means for resisting movement of the valve ele ment vto a closed position shutting off flow through the conductor.

Still another object of the invention is to providefin a device of the character 'just'described,

means for varying the force exerted by the resilient means, or a changeable means for restricting flow of iluids through the device, or both, whereby the value of the predetermined uuid pressure differential required to close the valve may be readily altered.

It is a\ particular object of theinvention to provide a well flow control -device for use in 'con-z junction with the well surface controls,V such as chokes, valves, regulators and the like, of a owing well and which is arranged to provide a DOsitive-and automatic sub-surface shut-off of flow of well fluids through the well flowcom and larger area thereof, so as to create a greater force acting upon the valve element and, thus, .to assure its closure. v y

A still further object of the' invention is to provide, in cmbination with a well fluid flow control device of the character described, improved means ior causing reopening of the device to resume owing of the well, which means is ac,- tuated by a suitable tool introduced into the flow conductor and operable to cause such resumption of ow without disturbing the position of the control device in the conductor or removing it from the conductor.

Another object of the invention is-to provide a well control device, of the character described, l

which is automatically actuated by the uid pressure diierential thereacross Aand which is readily adjustable so as to be actuated by a desired uid pressure dierential, said device being so constructed that, if desired, it may be,

lowered into, locked in, and removed from the well now conductor by means of tools operated by a iiexble cable or line, or, which may be directly coupled in the ow conductor.

Additional objects and advantages 'of the invention will be apparent from awreading of the following description of a device constructed in accordance with the. invention, and reference to. the accompanying drawings thereof, wherein:

Figure l is a view, partly in elevation and partly'in section, of a device constructed in accordance with the invention and located in a well conductor,V

Figure 2V is an enlarged view, partly in elevationand partly in section, of thecontrol device,

. showing the valve in its open position, A

ductor when the said surface controls are damaged, regardless of whether `the damage be caused by dow-cutting or by an outside impact or otherwise, whereby the well will not be permitted to flow in excess of predeterminedv ow conditions.

' Still another object of the invention is to provide an improved well control device, of the character described, which is arranged to be actuated by the :duid pressure dierentials created thereacross by the flowing well fluids, and wherein uctuating velocities of iiow, such as occurv in wells whichflow-by heads or surges, will not eil'ect premature closure of the valve. thereby providing for uninterrupted normal flowing' of. Y

the well. A.

Itis a ,further objectof the invention to provide. in a control device Voi.' the character de Figure 3 is a view similar to Figure 2, showing I views taken on the lines 8-8 and 9-9 respectively of Figure 1;

Fl'gurel is an enlarged transverse vertcaL.

sectional view of amodified form ofthe valve head forA use with the valve of Figure 2, and

Figure Il lis an enlargedlsectional view of the by-pass valve.

In-the drawings, the numeral I0 designates a tubular body or cage which is yformed with an axial bore II extending entirely therethrough. The central portion of the bore is enlarged as shown at I2, while the lower'portion is still further enlarged to provide a chamber I3. The annular shoulder which is formed between the bore II and the enlarged central portion I2 is inclined or bevelled to form an annular valve seat I4.

An orifice or guide block I5 has its upper end portion secured by screw threads to the lower portion of the chamber I3 so as to close the lower end of the chamber. The guide block has an axial opening or bore I6 which is enlarged at its lower portion to provide a packing recess I1. A plurality of composition chevron or pressure seal type packing rings I8 are mounted in the recess I1 and are held therein by means of a packing gland I9 which is threaded into the lower end of the recess. The gland I9 is provided with an axial bore corresponding to and forming an extension of the bore I6 of the guide block below the packing rings..

A plurality of radial recesses 2I are formed in the central portion of the outer periphery of the guide block, and a vertical restricted flow passage 22 extends upwardly through the guide block from each of these radial recesses, as is clearly shown in Fig. 2, whereby communication is established between the outside of the guide block and the chamber I3 bymeans of the radial recesses and the vertical iiow passages. Thus, well fluids may enter the radial recesses, flow upwardly through the restricted ow passages 22 into the chamber I3, from which they may iiow upwardly past the valve seat I4 and through thebore Il of the cage I0. The number and size of the iiow passages 22 may, of course, be varied as desired.

For controlling the iiow of fluids through the device, a Valve element 23 is provided. This valve'element includes an enlarged valve head 24 which has its upper edge bevelled and adapted to engage the inclined or bevelled seat I4 within the cage I0. An elongate valve stem 25 extends downwardly from the valve head 24 through the axial bore I6 of the guide block and the bore 20 of the packing gland I9 and is slidable longitudiy nally therein. The lower end of the stem extends a considerable distance below the gland Is and is provided with screw threads 26. For constantly urging the valve element downwardly, so as'to urge the valve head 24 away from the seat I4, a coiled spring 21 surrounds the stem below the gland. This spring has its upper end engaging the under side of'the gland I9, while its lower end rests upon a flanged washer 28 which is slidable on the stem 25. The washer 28 is adjustably retained in position on the stem 25 by means of lock nuts 29 which are threaded onto the lower end of said stem. Manifestly, the compressed spring exerts its 4force to constantly urge the valve element 23 toward its lowermost position, as shown in Fig. 2, and the spring pressure may be readily varied by adjusting the lock nuts 2S.

The lower projecting endet the stem 25, together with the coiled spring 21 and itsassociated parts, are completely enclosed by an elongate of the orifice or guide block I5. This ring lightly engages the upper portion of the valve stem 25 as it moves longitudinally therethrough and prevents sand and other foreign matter4 from entering the space between the stem and guide block and causing the valve element to stick in an open or closed position. f

Above the valve seat I4, a radial opening or port 34 extends through the wall of the cage III and provides communication between the exterior of said cage and the bore I I thereof, whereby fiuid may flow through said port-to the bore of the cage when the port is open. The port is provided at its inner end with a -valve seat and a valve member 35, having a head with an inwardly extending nose 36, is mounted in the opening or port and is arranged to engage said seat to close said port. A coiled spring 31 surrounds the valve stem and resiiiently holds the valve head against the seat. The spring is held in compression within the port by an orifice plate 38 which is secured in the outer portion of the port and has a central opening, slightly larger than the stem of the valve, through which well iiuids'enter the port. As clearly shown in Fig. l1,

the nose of the valve head extends or protrudes I into `the bore of the cage, and it will readily be seen` that a suitable tool (not shown) having a rod or prong 39 may be lowered through the well conductor until said prong engages thev protruding nose of the valve member and moves the head o f. said valve member from its seated or closed position to permit ow of fluid through the port into the b ore of the cage.

The assembly as above describedis adapted to be positioned or mounted within a well tubing or tubular housing or cover 30 which is connected by :crew threads to the lower end of the guide flow conductor A. The assembly may be positioned by any suitable means or in any suitable manner but, as illustrated in Figs. 1, 2 and 3, said device is connected to the lower end of a running and locking tool T. Therunning tool includes anA elongate tubular mandrel 40 which is provided with pressure seal type packing elements or cups 4I on its lower portion. Above the packing cups, the mandrel hasa slip expanding portion 42 which is arranged to coact with gripping slips 43 which are slidably mounted on the mandrel. The slips are carried by a suitable carrier or sleeve 44 and upward displacement of the carrier and slips from the mandrel is prevented by an external flange 45 which is formed on said mandrel. Thisvtool is substantially identical with the tools shown and described in patents, Nos. Re. 20,546 and 1,972,791, issued to Herbert C. Otis, and, obviously, maybe locked at any desired elevation within the tubing by means of lowering and removing devicesoperated on a wire line or cable as set forth therein.

In use, for lowering the device into the well flow conductor or tubing A, a suitable lowering device (not shown) is connected to the running or locking tool T in the manner described in the aforementioned patents and, suspended from a flexible line or cable, the assembly is lowered into the well. While lowering the assembly, the well surface controls, which will ordinarily include a variable choke or needle valve C, as well as other suitable and customary well surface control devices, are closed to prevent any iiow through the opened to permit the well fluids to flow upwardly through the tubing. Since the cups di prevent fluid from flowing upwardly outside the running tool T, all flowing duids pass through the radial openings 2| and restricted orifices 22 to the bore il of' the cage, from whence they flow upwardly through the mandrel 40 to the well surface and outwardly through the surface controls.

Ordinarily, the well production is controlled by adjustment of the choke C to increase or decrease the amount of flow.'4 Therefore, when the well surface controls are opened to permit the well to be'owed, the surface choke C is adjustedto secure the desired predetermined vnormal rate of production. During such normal predetermined now the valve of the control device remains open.

The well fluids will ow through the restricted passages 22 of the guide block without creating lany appreciable pressure diderential until the size of the flow controlling opening of the surface choke C,v or other surface control, is effectively equal to or greater than the combined areas of the restricted passages. When this condition is reached, a fluid pressure differential is created across the guide block, andi since the well fluids enter the cover through the port 32 below the guide block, it will be seen'that the higher upstream -pressure below the assembly acts upon the cross-sectional area of vthe valve stem ,25

ywhich extends below the packing i8. Due to the fact that theupper end of the valve element is exposed to the lower downstream pressure above the'guide block,it is apparent that thedifferential between upstream and downstream pressures acting upon the cross-sectional area of' the 'valve stein will'tend to urge the valvestem upwardly against the force exerted thereon by the spring 2L When the pressure differential has reached a suihcient value to move theA stem upwardly against the compression of the spring, the valve .head will engage the seat i4 and close off allflow As the valve head enters through the device. the central portion i2 of the bore of the cage, the point of restriction of flow is changed from the passages .'22 in the guide block to the space be\ of water, by drii'twood or ships striking the suro face connections, as well as by many other agencies.

It will readily be seen, however, that in the event of the occurrence of such damage to a well wherein a control device of the type just described has been installed, any flow .of well fluid at a rate sucient to create a pressure differential vacross the device in excess of the predetermined vdifferential for which the device is set, will immediately cause the valve to close to shut off flow of fluids through the conductor in which it is located. Thus, the well is prevented from flowing wild and waste ,of the well uids is substantially eliminated. Since the valve shuts off flow through the conductor, the damage to the surface controls or connections may be repaired in safety beforethe valve is reopened.

To open the valve after it has closed, a suitable tool (not shown) having a rod or prong 39 depending therefrom is lowered into the conductor by means of a flexible line until it engages the protruding nose 36` of theV by-pass valve 35 and forces said valve member outwardly away from the seat in the port 34, thereby opening the port Ato establish communication between the well fluid below the assembly and the bore of the Well conductor above the device. Manifestly, once the valve is opened, the well fluid may flow through the port 3d until the forces acting downwardly upon the valve element 23, that is, the fluid pressure above the valve -plus the force exerted by the spring 2l, are great enough to move said valve element downwardly against the pressure tional compression introduced into the spring 2 by the upward movement of the valve element.

lt is to be noted-that', since there isusually very little pressure diderential created acros'sthe valve vby a surging iiow action, the valve will remain 'open during such surging or heading flow, and

will close onlyv when sufficient fluid pressure dif- `ferentiaihas been created to move the valve element against the force of the spring. 'The valve element 23- is not exposed to the direct imadvantage over flow velocity orimpact operated valves, since such valves react more readily tosurging or heading flow, due to their `being exposed to the direct impact of the-flowing well It-is well known that'damage of many types may occur to the well surface controls. Damage vmay he caused by the cutting action of sand or other matter in the well uid stream, by unforeseen failure or accidental breakage of some of or locking tool T and jarring downwardly uponv ypact of the owing-well fluids. This is a. distinct` acting upon the valve stem below the guide block.

The same result may be obtained by introducingliquid, or iiuid pressure, into the well conductor 'lat the well surface in sufficient amount to cause the Valve element 23 to reopen. When the valve has-been reopened the well may, of course, again be flowed at the desired predetermined rate.

As is clearly shown in Fig. 11, `the ilow space ,between the stem of `the valve 35 and the central opening of the orifice plate 38 is made smaller in cross-sectional larea than any other annular space between the valve and the walls of the port. This is particularly true of the space between the nose 36 of the valve and the seat in the port, vsince this reduces the pressure differential'across the valve seat and minimizes' the cutting action 'of the flowing well fluids on these parts. Likewise.

the ilow space between the stem and the orifice plate is preferably made sufficiently small that the velocity of iiow through the port will not displace the rod or prong 39 from its position holding the valve open. Removal of the prong from 4within the bore Il will permit the valve to close.

The entire assemblymay be removed at' any time by loweringa suitable removing device (not shown) and engaging the sleeve 44 of the running the mandrel 40 to release the slips 43, whereupon the assembly may be lifted from the well conductor.

' lf desired, the fluid pressure differential required to move the valve element 23 to its closed position may be varied by adjusting the lock nuts 29 to increase or decrease the force exerted by the spring 2l in holding the valve element open. Or, the oriice or guide block l5 may be replaced with another having a dierent size or number of orifices. within the well conductor for further use. Thus. the many well flow' .conditions found in the vari- /ous oil or gas elds may-be compensated and the The tool may then be repositionedA desired predetermined closing conditions accurately provided for.

In Figure 10, a modied form of valve head is shown wherein an enlarged sleeve 50 having an internal annular flange 5| at its upper end is welded or otherwise secured to the upper end of the valve stem |25. A relatively soft packing ring 52 is confined between the upper end of the sleeve 60 and a valve tip 53 having a reduced lower portion extending downwardly through said packing ring into the upper portion of thev bore of the sleeve. A retaining nut 54 is threaded or otherwise secured to the lower end of the reduced portion of the tip and engages under the internal ange 5| of the sleeve to retain the tip in position. .'I'he upper peripheral edge of the tip is bevelled to engage the seat I4 and, when this engagement occurs, it will be seen that the fluid pressure acting upon the valve sleeve and stem will deform the packing ring 52 into sealing engagement with the wall of the enlarged central bore I2 of the cage 0. Thus, a seal will be assured even though the engagement of the valve tip with the seat I4 fails to close oi ilow.

A modified form of the invention is shown in Figures 6 to 9 inclusive. In this form, the control device is secured within the well tubing or ow conductor A by means of a connecting or supporting member 60 which is connected in the tubing string by means of screw threads. The

supporting member has an axial bore 6I which is flared outwardly at its upper end to substantially the diameter of' the bore of the tubing, and

through which all iiuid owing through the tubing must pass.

`The supporting member-is provided with an axial depending shank 62 which is externally screw threaded and which is adapted to receive the. upper end of theftubular body or cagey 10 of the control device.

The cage 10 has an axial bore 1|, the central portion of which is enlarged as shown at 12, and which is still further enlarged at its lower portion to form a chamber 13. The annular shoulder between the bore 1I and the enlarged central portion 12 is inclined or bevelled to form an annular valve seat 14.

An elongate cylindrical housing 16, having an axial bore 16 extending therethrough, is secured by screw threads tothe lower end of the cage 10. The upper end of the bore 16 is reduced and immediately below the reduced portion an offset is provided, whereby an internal annular shoulder 11 is formed within the bore of the housing. Below the offset portion a second and smaller shoulder 18 is provided.

The lower end of the bore 16 is enlarged slightly to form a small shoulder 19 and below the shoulder the bore is provided with internal screw threads 80. A thimble or cap 8| is threaded into the lower end` of the bore of the housing. lThe thimble has a bore 82 which is completely closed at its lower end, and a plurality of laterial openingsv 83 are provided in the wall of the thimble to admit uid into its bore. The upper end of the bore 82 is enlarged to form an upwardly kfacing internal annular shoulder 8l.

A valve element 85, having an enlarged re-l placeable head 86 and an elongate tubular shank or stem 81, is slidable longitudinally inthe bores of the cage and housing. The upper end of the valve stem is slidable in the upper reduced portion of the bore 16 of the housing so as to be guided in its vertical movement, and the valve head is movable within the chamber 13. The lower end of the stem 81 is formed with an annular boss 88 and a guide ring 88 surrounds the boss. The upper portion of the bore of the guide ring is reduced in diameter so as to engage over the boss and the ring has a tight fit on said boss. The periphery of the ring has a diameter slightly smaller than the bore 16 of the housing whereby it has a free sliding fit therein.

A' replaceable oriced choke member or bean 90 is secured by means of screw threads to the lower end of the valve stem 81 and extends therebelow into the cap or thimble 8|, as is clearly shown in IFig. 6. A plurality of packing rings 9|, which are preferably of the chevron or pressure seal type, surround the bean and are confined in sealing position between a packing ring 92 supported upon the upwardly facing shoulder 84 in the thimble and a stop ring 93 whichis held securely between the upper end of the thimble and the shoulder 19 at the lower end of the housing. The lower end of the bean is spaced from the closed end of the thimble at all times, whereby uid entering the lateral openings 83 may enter the orifice of the bean and ow upwardly through the tubular stem 81.

The upper end of the stem 81 is provided with lateral flow openings or slots 94 spaced therearound in the wall below the head 86.A It is noted that the slots 94 are always located above the upper end of the housing 15, even when the valve element is in its lowermost position, as shown in Fig. 6.` Thus, fluids flowing through the stem, may ilow outwardly through the slots into the chamber 13.

A plurality of secondary packing rings 95, also preferably of the chevron or pressure seal type,

\ surround the upper portion of the tubular valve 40 stem 81, the uppermost ring abutting the shoulder 11. The lowermost packing ring rests upon a follower or adjusting ring 96 which has its outer edge abutting the shoulder 18. Manifestly, the space between the ring 96 andthe shoulder 11 forms a packing chamber for the packing rings. A coiled spring 91 surrounds the stem 81 and has its upper end engaging the under side of the adjusting ring 96, while its lower end engages the top of the guide collar 89. The spring is under compression and exerts its force to .constantly urge the valve element 85 downwardly within the housing and cage, and away from the seat 14.

Downward movement of the valve element within the housing is limited by the engagement of the lower end of the stem 81 and the guidecollar 89 with the'stop ring 83 supported on the upper end of the thimble 8|. Upward movement of the element is limited by the engagement of the valve head 86 with therseat 1I in the bore of the cage 10.

The valve head 86 is shown as including a sleeve |00, which is Athreaded into the upper end of the valve stem 81, and within which the elongated shank of a valve tip |0I is slidable. A relatively softpacking ring |02 is confined between the upper end of the sleeve |00 and the enlarged upper end of the tip |0I. AA retaining nut |03 is threaded 0r otherwise secured to the lower end of the shank of the tip |0| and engages the lower end of -the sleeve to retain the tip in position. The upper peripheral edge of the tip is bevelled to engage the seat 14 and when this occurs, the fluid pressure acting upon the valve stem will deform the packing ring into sealing engagement with the wall of the enlarged central portion l2 of the bore of the casein the event the tip IUI fails to close oi flow. The valve head may, of course, be made ofy solid metal similar to the head of the valve illustrated in the previous form.

A by-pass or equalizing valve |35 is provided in the wall of the cage above the seat 14, in the same manner and of the same construction as either control device may be positioned in any suitable manner and that the means illustrated are merely two of the many fo`r accomplishing the purpose.

When the control device has been positioned in vthe well conductor and the surface controls adjusted to permit ow of the well fluids, it will readily be lseen that flow of such fluids upwardly outside the cage and housing is prevented by the supporting member 60. and that ilow upwardly outside the valve element is prevented by the packing rings 9| and 95. Therefore, th'e flowing well fluids will enter the lateral openings 83 in the thirnble, flow through the orifice in the bean @t and through the bore of the stem-81 and outwardly through the slots 94 into the chamber 13 in the cage. The iluids. will then iiow upwardly from vthe chamber past -the seat 14 and through the bore l l of the cage and the bore lGl'of the supporting member to the bore of the well conductor or tubing and through the surface flow control devices.

The bean 90 is provided with an orifice of a size which will permit ow of the well fluids at the' desired predetermined rate, and thefwell fluids will ow through the restricted oriilce of saidbean without creating any appreciable fluid pressure differential until vthe sizeof the ow controlling opening of the surface choke C, or other surface control, is equal to or greater than the when this differential is increased in amount until it is sufficient, when acting upon the crosssectional area of the bean, to move the valve element upwardly against the downward force ex- Operation and adjustment of the control device is substantially identicalwith that of the previous form. The oriced bean may be changed fora bean having an oriceofv a different size, or the force exerted by the spring may be varied'by varying the thickness of the' follower or adjusting ring 96 used to change the amount-of compression put into the spring.l v

- Should the lower packing rings V9| fail to seal off upward' iiow of well fluids f outside the bean, the secondary or upper packing rings 95 will seal against the valve stem 81 to permit functioning of the device. -These upper packing rings 'also serve as a wiper to prevent sand and other matter from entering from the chamber'lt into the space between the valve stem and the housing 1.5, where it might prevent operation of the device.

v memberexceeds a predetermined value.

It will be seenI that both forms of vthe invention are actuated by fluid pressure differential, and`therefore are less subject to be moved to a closed position by a surging or heading well now,

whereby normal uninterrupted predetermined flow of the wellfluids is permitted, but, upon failure of .or damage to the well surface connections or controls which permitsa larger ow than such predetermined rate, both forms of thein- 'vention are adapted to immediately. close and shut off further flow through the well conductor.

The above description of the invention is explanatory only, and changes in details of the constructions illustrated may bemade by those skilled in the art,'within the scope of the appended claims,. without departing from the spirit of the invention.

What we claim and desire to secure by Letters i Patent is:

l. A well flow control device including, a support having a flow passage therethrough, `flow erted by the spring 91, the valve element will beV lifted until the valve head 86 engages the seat 'It to close oi all upwardflow through the well conductor.

As the valve head lenters the central portion l2 of the bore ofthe cage. the -area of application of the fluid pressure differential is transferred from the bean Q0 to the larger cross-sectional 'area of the valve head, thus causing the valve to snap closed and also supplying suiiicient. energy to overcome the additional compression introduced into the spring 91 by the upward move ment of the valve element.

' Once flow has been shut oi by closure of the valve element 85, ow may be resumed byv opening'the by-pass or equalizing valve l'35 by means of a prong 39 lowered in the same manner as was described-for operation of the valve 35 of the previous form. l

restrictive means for creating a, fluid pressure differential across the support, a valve member exposedxto Vand actuated by such iiuid pressure 2. A well flow control device for flowing wells including, a tubular body having an axial bore and a valve seat provided therein, a tubular valve element having a restrictedflow passage therethrough mounted within the b ore of the body and movable with relation to the valve seat, said lelement being adaptedto engage said seat to shut off flow through the body, the upper end oi said valve element being exposed to the pressure I of the well -fluid above the body with its lower end exposed to the well pressure below the body vwhereby said element is actuated by the difieren tial in said iluid pressures, means for protecting the lower end of the valve element from' direct impact of the well iiuid, and means normally' holding said element in unseated open position to permit flow of fluids through the body, said means being set to permit the valve element to engage the valve sea-t to shut off flow through the body upon the application of a predetermined fluid pressure differential across said valve element.

3. A well flow control device for flowing wells including, a tubular body having an axial bore and a valve seat provided therein, a valve element mounted in the bore of the body and movable with relation to the valve seat, said element having a closure head and a tubular valve stem with a flow restricting member therein, said valve element head being adapted to engage said. valve seat to shut off flow through the body, the upper end of said valve element being exposed to the pressure of the well fluid above the body with its lower end exposedto the well pressure below the body whereby said element is actuated by the differential in said pressures, means for protecting the lower end of the valve element from direct impact of the well fluid, and resilient means normally holding said element in unseated open position to permit flow of fluids through the body, said means being set to permit the valve element head to engage the valve seat to shut off flow through the body upon the application of a predetermined fluid pressure diflerential across said valve element, by the restriction of flow of well fluid through'the restricting member of the valve element.

4. A well flow control device including, a support having a flow passage therethrough, means for creating a fluid pressure differential across the support, means normally open while the fluids port having a flow passage therethrough and a valve seat in said passage movable valve closure means carried by said support and normally held lopen to permit flow through said passage and adapted to be moved to engage the valve seat in the passage to shut off flow through said passage,

means protecting said closure means from exposureto direct impact of fluid flow through the conductor, and fluid flow restricting means ineffective during predetermined normal flow of the fluid and adapted to restrict flow through the passage of the support in the event the flow vof.' the fluid exceeds said predetermined normal flow,

' whereby a fluid pressure difference is set up across are flowing through the support and actuated by fluid pressure differential for closing of ow through the conductor when the fluid pressure differential acting thereon exceeds a predetermined value, means for protecting said normally open means against direct impact of the flowing fluids, and means for changing the point of application of fluid pressure ldifferential to said norrestricting means for creating a fluid pressure differential cross the support, closure means normally open while the well fluids are flowing through the support to permit predetermined flow therethrough, said closure means being actuated by the fluid pressure differential for closing o flow through the conductor when such fluid pressure differential exceeds a predetermined value, and means shutting off said normally open closure means from exposure to direct impact of the flowing well fluid.

6. A well flow control device including, a housing having a ilow passage extending therethrough, flow restrictive means carried by the housing for creating a fluid pressure differential across said housing, a valve mounted in the housing and exposed to said fluid pressure differential, means for holding said valve normally open during predetermined flow and set to yield when the fluid pressure differential across said valve is unequalized to a predetermined degree whereby 'the flowing well fluid will close said valve, and means shutting off said valve ,from exposure to directl impact of fluid flowing through the well conductor.

7. A well flow control device including, a supthe movable valve closure means to cause said means to move into engagement with the valve seat to shut off flow through the passage of the support.

8. A well flow control device for flowing wells including, a tubular support, a stationary valve seat within the passage, a valve member movable relative to said seat and having an upper portion exposed to the flowing uid pressure in the tubing above the support and a lower portion exposed to the well pressure below the support so as to be operated by the differential in said pressures, flow restrictive means carried by the support for creating a fluid pressure differential thereacross, means for normally restraining the valve member away from the-valve seat in open position, whereby a predetermined pressure differential is required to move said member from such open position to closed position to shut oil flow of fluids through the support, and means for protecting said movable valve member from exposure to direct impact of fluid flowing through the well.

9. A well flow control device including, a valve body having a bore therethrough', a guide block carried by the body and having restricted flow passages therein for restricting flow through the body to create a fluid pressure differential across said block, a valve element slidable in the 'guide block and exposed to the uid pressures on opposite sides of vsaid block whereby said element is actuated by the differential in such fluid pressures, means closing off the valve element from exposure to direct impact of fluid flowing through the well, and resilient means normally holding said valve element in its open position and' set to yield to permit the element to be moved to a closed position when the fluid pressure differential across the guide block exceeds a predetermined value.

10. A well flow control device including, a support having a fiow passage therethrough, .now restricting means carried by the support for creating a fluid pressure differential across the support, a valve member actuated by such fluid pressure differential for closing off flow through the support, means for normally holding said valve member open and set to yield to permit the valve member to close when the fluid pressure differential acting upon said member exceeds a predetermined value, means for protecting said valve member from exposure to direct impact of fluid flowing through the conductor, and means carried by the support above the valve member and operable from the well surface to equalize pressure across'the valve and for causing thelatter to open after it has closed.

HUBERT C. LAIRD. HERBERT C. OTIS.

cERfr'IFIcATE oF fcoRREcTIoN.

Patent No. 2,575,05Li. April 5, 19u15.

v HUBERT C. LAIRD, ET AL.

It is hereby oertified that error appears in the printed speeificatiori ofthe above numbered patent` requiring correction as fo'llcmsPage Lp, first oolumn, line 65, `for "laterial" read '-1atera1; page 6, first column, line 14.9, .claim 5, for cross read -across; and'second column; line 2, Claim 7, (After. the word "passage" insert a comma; line 20, claim 8, after "support". insert e-having a flow passage therethrough-; and that the said Letters Patent should' be read 'with vmis cari-ection .therein that the same may conform to the record Aof the case in the Patent Office.-

signed and sealed this 1913i diy of June, A. D. 1915.

Leslie Frazer (Seal) Acting Commissioner of atents,

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