US2594831A

US2594831A - Well flow device

Info

Publication number: US2594831A
Authority: US
Inventors: Robert O Walton
Original assignee: MERLA TOOL CORP
Current assignee: MERLA TOOL CORP
Priority date: 1947-11-12
Filing date: 1947-11-12
Publication date: 1952-04-29
Anticipated expiration: 1969-04-29

Description

April 29, 1952 R. o. WALTON WELL FLOW DEVICE Filed Nov. 12, 1947 ZlwuM WM Robert O- Walton Patented Apr. 29, 1952 2,594,331 WIELL FLOW DEVICE Robert Walton, Dallas, Tex., assignor to Merla Tool Corporation, Dallas, Tex., a corporation of Texas Application November 12, 1947, Serial No. 7 85,331

' '7 Claims. (Cl. 137-111) This invention relates to new and useful improvements in well flow devices.

This invention is an improvement on the device shown and described in my co-pending application, Serial No. 451,570, filed July 20, 1942, now abandoned.

One object of the invention is to provide an improved device for controlling the admission of a lifting fluid, such as gas, into a liquid column within a well tubing or conductor for lifting or raising the liquid to the surface, said device being particularly adapted for use as an intermitter to intermittently admit the lifting gas at predetermined intervals in accordance with particular well conditions.

An important object of the invention is to provide an improved well flow device having all of the advantages of the device disclosed in my prior co-pending application, and in addition having an improved inlet valve assembly which includes a power bellows unit associated with a novel main valve stem construction, whereby more efficient flow control is had.

A particular object of the invention is to provide an improved flow device wherein the operation of a main valve element is controlled by actuation of a pilot valve member with both the main and pilot valves and their co-acting seats being so constructed that more efiicient seating of the valves is assured and also so that cutting out or undue wear on said valves and seats is eliminated.

A further object of the invention is to provide an improved device, of the character described, wherein the main control valve includes a valve head having an upwardly projecting stem, with said stem being constructed to substantially shut ofi flow past the valve head immediately prior to said head engaging its seat, whereby fluttering of the main valve is eliminated and also whereby the valve head is not subjected to'excessive cutting action by the fluid flowing past said head. Still another object of the invention is to provide an improved flow device, of the character described, which is so constructed that a full back check to prevent reverse flow past both'the main and pilot valves may be employed therewith without changin the various basic component parts which form the device.

The construction designed to carry out the invention will be hereinafter described together with other features of the invention.

ffThe invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawing, wherein an example of the invention is shown, and wherein:

Figure l is a view, partly in elevation and partly in section, of a flow device, constructed in accordance with the invention,

Figure 2 is an enlarged, horizontal cross-sectional view, taken on the line 22 of Figure 1,

Figure 3 is an enlarged, sectional detail of the pilot valve and its associatedseat,

Figure 4 is an enlarged, sectional detail of the main valve and its associated seat,

Figure 5 is an enlarged, horizontal, sectional view, taken through the valve stem of the main valve,

Figure 6 is a transverse, sectional detail of a modified form of main valve unit, and

Figure "I is a horizontal cross-sectional view, taken on the line 1-! of Figure 6.

In the drawings, the numeral Ill designates a well tubing or conductor through which the well fluids flow upwardly. A valve device constructed in accordance with the invention is adapted to be connected with the well tubing and is arranged to control the admission of a lifting fluid such as gas or air from the space outside of said tubing and into said tubing to lift or raise the well liquids within said tubing to the surface.

The flow device includes a main intake valve assembly A, a power bellows unit B and a pilot valve assembly C, these parts being connected together, as will be explained, to form said device. As is clearly shown in Figure 1 the main intake valve assembly includes a tubular casing l l which has a boss i2 formed on one side thereof and said boss is connected, as by welding or otherwise, to the tubing ID. The tubing is provided with a radial inlet port I 3 which communicates through an opening It with the bore I la of the valve casing l I. A valve seat element I5 is threaded into the lower end of the casing II and has its upper portion formed with an axial bore IS, the extreme lower end of which is provided with an annular, bevelled or inclined valve seat H which presents a flat surface. Immediately above the annular seat ii, the bore is counter-bored as indicated at Ha and the purpose of this counterbore will be hereinafter explained. The lower portion of the element l5 has an enlarged outer bore 18 and a tubular screen pipe I9 is threaded 3 13 into the well tubing. The admission of lifting gas or air into the liquid column will function to raise or lift the liquid to the surface.

For controlling the admission of the lifting gas or air into the tubing from exteriorly thereof, a valve element 29 is provided. This valve element includes a stem 2| which is generally triangular in cross-section and which is slidable within the bore [6 of the valve seat element l5, whereby flow passages 22 (Figure are formed between the sides of the stem and the wall of the bore. To provide for increased flow past the stem, the outer surfaces of said stem may have longitudinal grooves 23 cut therein and in this manner a restricted flow past the valve stem within the bore 16 may be had. A valve head 24 is formed at the lower end of the stem and has an upper seating surface 25, this surface being arcuate or curved and being adapted to engage the annular, bevelled valve seat l'i. Immediately above the curved seating surface 25 (Figure 4) of the valve element is a cylindrical section 26 which has an outer diameter substantially equal to the diameter of the bore i6 and which has a greater longitudinal width than the depth of the counter-bore Ila which is disposed immediately above the seat ll. The cylindrical surface 26 has the lower end of the grooves 23 of the stem terminating adjacent thereto and since the diameter of said surface is substantially equal to the diameter of the bore I 6,a slide valve arrangement is obtained. Of course, in moving upwardly into the bore Hi, the cylindrical portion must pass through the counter-bore I'l-a and because the length of said portion 25 is greater than the depth of the counter-bora'the cylindrical portion 26 enters the bore l5 prior to the time that the curved seating surface 25 engages the annular valve seat I1. When the curved seating surface 25 of the valve head is engaging its seat as shown in Figure 4, the cylindrical" surface 26 is disposed within the bore and inf such position the valve element 28 is inits raised'or lifted position, whereby an upward flow of; lifting gas or air into the tubing is prevented.

The lower end of the valve head is formed with a seati-ng surface 2? which is also curved and which is similar to the upper seating surface 25. The lower seating surface 2'! is adapted to engage an annular bevelled valve seat 28 which is formed at the upper end of the bore of the screen l9 and-when the valve is in a completely lowered position with the surface 27' engaging said seat, a back now of well liquids from the tubin Ill downwardy through the valve assembly A is prevented.

The pressure of the lifting gas or air which is present exteriorly of the valve device constantly acts against the'lower end of the valve element 28 to hold the same in its raised position. To effect an opening-of the valve element 26 to permit an admission of'lifting air or gas into the tubing,'the power bellows unit Bis provided. This unit includes a tubular housing 29 which is coupled to the outer casing of the valve assembly A by a suitable coup-ling collar 30. The coupling collar has an extension 3! at its upper end and the lower end of an operating bellows 32 is connected therewith. The upper end of the bellows is suitably fastened to an enlarged head 33 which is preferably formed integral with the upper end of an operating stem 34. The stem has its lower end slidable through an axial bore a formed within the coupling 30' and the extreme lower end, o'fsaid stem is adapted tov engage the upper end of the valve stem 21 of the main valve element 20. The normal inherent resiliency of the bellows 32, as well as the pressure acting against the lower end of the valve 20, tends to expand said bellows and thereby hold the operating stem 34 in its raised or lifted position, as shown in Figure 1; thus, it is apparent that the main valve element 20 may be moved to its upwardly seated position by the pressure of the lifting gas or air which is acting against its lower end.

When a pressure is applied to the upper end of the head member 33 of the operating stem, the stem is moved downwardly, with the bellows 32 being collapsed by this pressure and downward movement of the operating stem imparts a downward movement to the valve element 20 to unseat the same and admit lifting gas into the well tubing iii. When pressure against the upper end of the head 33 and bellows is relieved, the bellows will function to return the operating stem 34 to its raised position and any pressure within the housing 29 exteriorly of the bellows may escape through a suitable vent passage 35 which is formed in the coupling 39 and which extends from the bore 380:. It is noted that the lower portion of the operating stem 34 is constructed of hexagonal material or it may be fluted or grooved to provide a by-pass area within the bore 30a.

The power bellows and its associated operating stem 34 are adapted to be moved downwardly toopen the main valve 20 by the pressure of the lifting gas or airwhich is present outside of the tubing and flowdevice. For controlling the application of this pressure to the upper endof th e bellows assembly, the pilot valve assembly C isprovided. This assembly includes a tubularouter casing 36 which has its lower end connected to the outer housing 29 of the bellowsu'nit 'B- by means of a coupling collar-31. A valve seat member 38 is threaded into the upper-end of the bore 31a of the coupling 31 and has an annular bev elled or inclined valve seat 39. The seatinember 38 has an axial bore 38aand through this bore, as well as through the bore 31a ofthecoupling, communication is established between the interior of the outer casing 3B'of the bellows assembly C and the upper end of the power bellows 32 and its head member-33. The lifting gas or ainunder pressure may enter the interior of the casing 36 through suitable inlet openings 40.

For controlling the flow past the valve seat 39, a pilot valve 4| is mounted within the outer casing 36. This valve includes a head member 42 having a semi-spherical seating surface 43 at its lower end,

the latter surface being adapted to seat or engage the annular, bevel-led valve seat 39. Anupwardly extending stem 42a is connected to the valve head 42 and projects axially within the casing 36; Through a suitable connecting coupling 4'4 the upper end of the valve stemis connected to a pilot. bellows 45 and the latter has its upper end; fasa tened to a cap member 46. The capv member, is provided with an external flange whichv engages the upper end of the casing 3 6 and a retaining collar 41 threaded onto said casing confines. the. cap. The cap is formed with a. tapered. axialbore 46a adapted to be closed by a tapered. cylindrical plug 48 and the interior of the bellows, is pai:

tially filled with a suitable non-compressibleliq uid whereby the retraction of. the bellows "islitnited to prevent rupturing thereof by excessive,

pressure. A guard sleevej l9v hasits upper end en gaging an annular, shoulder on the cap. 46, andsaid sleeve. extends downwardly, over; the} bellows;

49, with sufficient clearance between the lower end of the guard sleeve and the stem 43 to permit the pressure within the casing 36 to act on the outer surface of the pilot bellows. Also a plurality of inlet ports 4911 may be formed in the wall of the sleeve.

The normal inherent resiliency of the bellows moves in a direction to expand said bellows and thereby urge the pilot valve toward a seated position. For positively holding the pilot valve seated and also to control the pressure required to unseat said pilot valve, a coil spring 50 surrounds the valve stem 42a and is confined between an inwardly directed flange 4911 on the guard sleeve 49 and adjusting nuts 5| threaded onto the stem. The spring also functions to hold the guard sleeve in place. Obviously by adjusting the nuts, the tension on the spring 50 may be regulated and this spring is added to the inherent resiliency of the pilot bellows 45 to .urge the pilot valve to a seated position.

When the pressure of the lifting gas or air exteriorly of the device reaches a predetermined point in accordance with the size and strength of the spring 50,, this pressure being present within the interior of the casing 36 acts upon the bellows 45 to collapse said bellows and thereby lift the valve stem 42a. and the valve 42 against tension of the spring 50. When the pilot valve is lifted, the pressure of the lifting gas or air may pass downwardly through the bore 38a of the seating member 38 and the bore 31d of the coupling 3'! and act against the upper end of the power bellows 32 to move said bellows downwardly and thereby move the operating stem 34 connected with said bellows downwardly against the main valve element 26. This results in an unseating of the main valve, which as explained, admits the lifting gas or air into the tubing 13.

In the operation of the device, the parts are normally in the position shown in Figure 1. In such position the main valve element 20 is raised and in a closed position and the power bellows 32 is in its expanded or upper position. The pilot valve is also closed, being held so by its associated coil spring 50 and the pilot bellows 45.

When the pressure of the lifting gas or air exteriorly of the device reaches a point sufiicient to move the pilot bellows toward a collapsed position, the pilot valve 42 is opened and the pressure of the lifting gas is applied to the upper end of the power bellows. The cross-sectional area of the upper head member 33 of the power bellows is greater than the cross-sectional area of the main valve head which is acted upon by the lifting gas and therefore the power bellows 32 is moved toward its collapsed position, whereby the operating stem moves the main valve downwardly off of its seat l1. As soon as this occurs the lifting gas from exteriorly of the tubing may flow past the valve seat I! and into the well tubing string in through the inlet port l3, whereby the well liquids within the tubing are lifted to the surface by said lifting gas or air. So long as the pilot valve remains open, the main valve is held in its unseated position and as soon as the pressure exteriorly of the device falls below a predetermined point, the pilot valve is automatically closed. Upon closing of the pilot valve, any pressure within the casing 29 and the power bellows assembly B is bled off through the bleeder passage 35 which permits the bellows 32 to return to its normal expanded position, whereby the gas pressure acting against the lower end of the main valve may again seat said valve. The parts remain in this position until pressure exteriorly of the tubing again reaches a point sufficient to open the pilot valve.

A particular feature of the invention is the construction of the main valve element 26. It will be noted that the seating surfaces 25 and 21 of the Valve head are curved and this contour or shape reduces the danger of said surfaces being cut out or damaged by the flow thereby. The pilot valve 42 has its seating surface also curved or ball-like for the same reasons. In addition the main valve has the cylindrical surface 26 immediately above its seating surface 25 and this cylindrical surface is of substantially the same diameter as the bore l6 of the valve seat element l5. When the Valve is being moved to a closed position, the cylindrical surface 26 enters the enlarged counter-bore l'la first and then moves into the bore 16 prior to the time that the seating surface 25 of. the valve head engages the seat 11. As soon as the surface 26 enters the bore l6, the flow of gas through the bore I6 is substantially shut off with the restriction being at the lower end of said bore which is well above the seat l'l. Therefore, as the seating surface 25 approaches the seat H, the extremely high velocity normally occurring by the constantly decreasing restriction is not present at this point and the surface 25 and valve seat are not subjected to the exceptionally high velocities which normally damage or cut out said surfaces.

In some instances it may be desirable to provide a complete back check which would prevent the flow of well liquids from the tubing back through the main valve 20 as well as the pilot valve 42. As explained, any back flow past the main valve element would move the main valve element to its completely lowered position with its lower seating surface 21 engaging the seat 28. This would prevent any flow of liquids from the tubing back through the valve assembly A. However, a flow might occur through the bleeder passage 35, then upwardly through the casing 29 of the power bellows unit and then through the coupling 3'! to act against the pilot valve. If the pressure of this liquid is sufficient, the pilot valve would be unseated which is, of course, not desirable. In order to permit a back check valve to be used to prevent reverse operation of the pilot valve in those conditions where needed, the coupling 37 may receive a ball valve indicated in dotted lines at 66 in Figure 3. A valve seat 6! is formed at the lower end of the bore 380. of the valve seat element 38. A light spring indicated by the dotted line 62 in Figure 3 is disposed beneath the ball 63 and rests upon an internal seat 3111 formed within the coupling 31. The spring is only of sufficient strength to support the weight of the ball 60.

When the ball 60 is employed as a check valve, opening of the pilot valve under normal operations will cause the pressure of the lifting gas or air to move the ball 60 downwardly into a reduced chamber 310 formed in the lower end of the coupling 31. Flow past the lowered ball 65 may occur through an inclined passage 63 which is provided in the coupling 31 and through this passage the pressure may be conducted to the upper end of the power bellows. Thus, there is no interference with the normal operation.

However, in the event that a back check valve is necessary, the pressure of the well liquids which would act upwardly against the underside of the pilot valve will strike the ball valve 60 and move it into engagement with the seat 6|,

whereby the pilot valve 42 is protected against this back pressure. As stated the ball check 60 may not be necessary under all conditions and the coupling 31 is so designed that said ball may or may not be used as conditions required.

As has been noted, a back pressure in the tubing may act upon the main valve element 20 to completely lower said element so that its lower seating surface 27 engages the lower seat 28. However, wells having excessively high back pressure conditions have been encountered and in such instances, the excessive pressure results in a very slow downward closing of the element 20. In Figures 6 and 7, a modified form of main valve assembly having a quick closin back check valve arrangement is shown. In this structure, a valve seat element H5, similar to element l of the first form is provided, said element having an axial bore H6, counter-bore Illa and bevelled seat I l 'l. A valve element I20, similar to the element 28, has its stem slidable within the bore H6 and is formed with an upper valve seating surface I25 on its valve head [24, which surface is adapted to engage the seat H1. A coil spring 5a below the valve element normally urges the same upwardly. The operation of the valve element I20, so far as controlling the admission of a lifting fluid into the tubing, is identical to the operation of the valve element 20, hereinbefore described.

Connected to the lower end of the valve seat element I I5 is a check valve housing 10 which is formed with a valve chamber H having its upper end inclined as indicated at l2. The spring 5a has its lower end supported on this housing. The tubular inlet screen 19 having the annular valve seat 28 at its upper end is secured to the lower 'end of the housing and closes the valve chamber H. A ball check valve 13 is confined in the housing and is movable between the upper end of the chamber and the valve seat 28.

When the ball is in its normally raised position in engagement with the upper end 12 of the valve chamber, a flow of the lifting fluid entering the screen is may occur upwardly through by-pass passages 14 which extend upwardly through housing at the sides of the valve chamber. The pressure of the lifting gas normally holds the ball lifted so that the flow device functions in the manner explained with reference to the first form of the invention. However, if an excessive back pressure occurs in the tubing Hi this pressure acting downwardly past the main valve element I24 exerts a force on the ball l3 which has portions exposed through the passages M and moves said ball onto the 4 seat 23 to shut off a back flow into the area outside of the tubing 10. It will be evident that the ball 13 is actuated solely by the pressures on opposite sides thereof and as soon as the back pressure in the tubing exceeds the pressure of the lifting fluid outside said tubing, the ball is immediately seated. This provides a quick closing back check valve, irrespective of the pressure conditions which might develop in the tubing and which would interfere with quick downward closing of the valve element of the first form. The use of the assembly illustrated in tails of. the illustrated construction may be.

made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A well flow device including, a main valve assembly having a flow passage therein with a movable main valve within the passage, said valve being adapted to be moved to an upper position to close upward flow through said passage and adapted to move to a lower position to shut off flow in a downward direction, a power bellows unit connected with the main valve assembly and including a bellows for unseating the valve from its upper position, said bellows unit being in communication with the passage of the main valve assembly, a pilot valve assembly connected with the bellows unit and including a pilot valve which controls the application of pressure to the bellows of said unit, and back check means interposed between the bellows unit and the pilot valve assembly to prevent any back pressure which may occur in the passage of the main valve assembly and in the communicating belows unit from acting upon the pilot valve, the back check means comprising a tubular coupling having a valve seat at its upper end and receiving chamber at its lower end, with a spring-pressed ball adapted to engage the valve seat when in its upper position and arranged to move downwardly within the receiving chamber out of the line of flow through said coupling when in its lower position.

2. A well flow device including, a main valve assembly having a flow passage therein with a movable main valve within the passage, said valve being adapted to be moved to an upper position to close upward flow through said passage and adapted to be moved downwardly to open flow through the passage, a power bellows unit having a power bellows therein, an annular bored coupling connecting the lower end of the power bellows unit to the upper end of the main valve assembly and having the interior of the power bellows communicating with its bore, said coupling also having a by-pas's establishing communication between the interior and exterior of the power bellows, an operating member secured to the power bellows for engaging the main valve whereby said main valve may be unseated when a predetermined pressure is applied to the exterior or" the bellows, a pilot valve assembly having a pilot valve for controlling the application of pressure to the exterior of the power bellows, a coupling connecting the upper end of the power bellows unit to the pilot valve assembly and having a valve seat therein whereby if desired a back check valve which will prevent excessive pressure within the power bellows unit acting on the pilot valve may be mounted within the last-named coupling.

3. A well flow device as set forth in claim 2, wherein the coupling connecting the power bellows unit and the pilot valve assembly has an internal axial chamber with the valve-seat at its upper end together with a communicating port extending from the upper portion of the chamber to the lower end of the coupling, and an upwardly seating ball check within the chamber adapted to engage the valve seat to close upward flow therethrough, downward movement of the ball check moving said check below the upper end of the communicating part to allow flow past the ball check.

4. A well flow device as set forth in claim 2,v

9 together with back check means in the main valve assembly below the main valve and independent thereof and adapted to be moved to a closed position when the back pressure in the flow passage of the assembly exceeds the pressure exteriorly thereof.

5. A well how device including, a housing adapted to be connected with a well conductor, a main valve assembly forming the lower portion of the housing and having a flow passage extending therethrough, the passage having a reduced bore portion, an annular valve seat at the lower end of the reduced bore portion, a main valve element Within the assembly adapted to engage the seat to shut ofi flow through the bore and normally held in a seated position by the pressure which is present exteriorly of the housing, a guide stern on the main valve element slidable within the reduced bore portion, a cylindrical sealing surface on the lower portion of the guide stem immediately above the seating surface of the valve element and having a diameter substantially equal to the diameter of the reduced bore portion, whereby as said sealing surface enters the bore prior to engagement of the valve element with its seat a flow past said valve and seat is substantially shut off, a coupling member having an axial bore and forming part of the housing and connected with the upper end of the main valve assembly, a power bellows within the housing connected with the coupling and having an operating member extending through the coupling and engageable with the main valve stem whereby when the bellows is moved toward a collapsed position the operating member functions to unseat said main valve and thereby allow a fiow through the passage into the conductor, the coupling having a passage establishing communication between the coupling bore and the area exteriorly of the bellows with the oper ating stem having a loose fit within the bore of the coupling to allow flow therethrough, said bellows being normally in an expanded position to permit the main valve to be closed, and a pilot valve means within the housing above the power bellows and normally in a closed position shutting off a flow to the power bellows, said pilot valve being opened when the pressure exteriorly of the tubing reaches a predetermined point to admit pressure to the power bellows, whereby the bellows is moved toward a collapsed position and the main valve is opened, closure of the pilot valve allowing bleeding off of the pressure acting on the bellows through the passage and bore of the coupling.

6. A well flow device as set forth in claim 5, together with back check means in the housing independent of the main valve and below said main valve element and arranged to be moved to a closed position when the back pressure in the passage exceeds the pressure exteriorly thereof.

'2. A well flow device as set forth in claim 5, together with back check means in the housing independent of the main valve and below said main valve element and arranged to be moved to a closed position when the back pressure in the passage exceeds the pressure exteriorly thereof, said back check means being exposed to the pressure exteriorly of the conductor and being held in a position out of the normal line of flew through the passage by said pressure.

ROBERT O. WALTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 192,642 Eokert July 3, 1877 738,026 Gill Sept. 1, 1903 1,542,612 Collar June 16, 1925 1,593,115 Blauvelt July 20, 1926 1,632,403 Grantland June 14, 1927 2,025,296 McIntyre Dec. 24, 1935 2,314,869 Boynton Mar. 30, 1943 2,342,301 Peters Feb. 22, 1944 2,368,406 Boynton Jan. 30, 1945 2,368,999 OLeary Feb. 6, 1945 2,385,316 Walton Sept. 18, 1945 FOREIGN PATENTS Number Country Date 309 Great Britain of 1914