GB2141508A

GB2141508A - Telescoping tubular coupler

Info

Publication number: GB2141508A
Application number: GB08334245A
Authority: GB
Inventors: Richard K Harris; James Richard Twomey
Original assignee: Slope Indicator Co
Current assignee: Slope Indicator Co
Priority date: 1983-06-17
Filing date: 1983-12-22
Publication date: 1984-12-19
Also published as: GB8334245D0; JPS604689A

Abstract

A telescoping tubular coupler (14) for incorporation in an end-to-end assembly of tubular elements (10, 12) comprises a casing for disposition in the earth to enable instruments to be passed down the casing for underground measurement purposes. The coupler (14) is formed from a cylindrical sleeve 16 with cylindrical liners (18, 20) slidably inserted into its opposite ends. Pin-and-slot connections (24, 26) permit limited relative longitudinal movement between each liner and the sleeve whilst preventing relative rotation. Each liner has an annular stop collar (32) for engagement with the end of the sleeve (16), to take compressive axial loading of the fully contracted coupler (14) in conjunction with the abutted ends of the two liners. Snap-action couplings (28, 30) secure the protruding ends of the liners (18, 20) to the respective tubular members (10, 12). <IMAGE>

Description

SPECIFICATION Telescoping tubular coupler The present invention is concerned with a telescoping tubular coupler for interconnecting tubular members. Such a coupler is particularly although not exclusively useful as an element in the assembly of an elongated tubular casing disposed in the earth for the reception and guidance of geophysical instruments used in making subsurface readings, such as readings of inclination due to earth movement, pore water presence or pressure and the like. Tubular casings are commonly inserted into the earth in well holes or drill holes and various instruments are caused to move therein to produce geophysical reading.

Typical instruments for detecting or deter mining movement in geological formations are called inclinometers. Fluid or gas pressure measuring devices are commonly called piezometers. Usually such inclinometer and piezometer instruments are carried within a torpedo-like body that is moved through the tubular casing. In the case of inclinometers the instruments have rollers or wheels, usually in opposed pairs or pairs of pairs, typically disposed at 90 degrees to each other. The interior surface of the tubular casings for inclinometer or slope detecting instruments usually have longitudinal grooves, typically four in number, to receive or orient and guide the torpedo by the rollers or wheels.

For convenience of manufacture and to facilitate transport of unassembied tubular casing sections, their length is commonly limited to about 3 meters (10 feet). Field assembly of a complete casing is accomplished by connecting a plurality of tubular casing sections into a string using snap-action couplings such as are fully disclosed in our co-pending British patent application no: 8334246 filed (case 5~corresponding to U.S.Patent Appln Serial no:505402) One major problem faced by practitioners in the field of subsurface investigation is that of damage to the casing caused by settlement of the earth.This settlement can result in the abutting ends of the casing sections tending to cup, curl, mushroom or otherwise deform in such a way as to obstruct the interior of the casing and impede passage of the torpedo containing the measurement instruments. Re-use of a damaged tubular section is not desirable because the cutting away of the damaged end section results in a non-standard length.

It is a primary object of this invention to provide a telescoping means which may be incorporated in one or more locations along the length of the casing to compensate for this settlement of the earth. Use of a telescoping means to solve the immediate problem also results in other advantages which facilitate plotting the degree of such settlement and its specific location along the length of the casing.

According to the present invention, a telescoping coupler for incorporation into an endto-end assembly of tubular members, comprises an elongate sleeve disposed in use as an extension of an end of a first tubular member, the sleeve having an axial bore; a tubular liner received slidably within one end of the said bore; the liner being disposed in use as an extension of a second tubular member which is disposed in end-to-end relation to said first tubular member; and in which there is interengagement between the sleeve and the liner which permits limited longitudinal relative movement therebetween but prevents relative rotational movement therebetween.Preferably the bore in the sleeve and the liner are both of circular crosssection, in which case the interengaging means may comprise an elongate slot and a pin entered into and slidable relatively to and along said slot, the slot and pin providing a sliding connection between the sleeve and liner.

In a preferred form of the invention, a second tubular liner, again preferably of circular section, may be slidably received within the other end of the bore of the sleeve and disposed in use as an extension of the first tubular member, there being interengagement between the sleeve and the second liner permitting limited longitudinal relative movement therebetween but preventing relative rotation therebetween, the arrangement permitting limited longitudinal relative movement between the adjacent ends of the two liners within the bore of the sleeve. The interengagement between the sleeve bore and the second liner is preferably once again by a pinand-slot sliding connection.

The first and second liners may both be formed to be detachably connected in use respectively to the second and first tubular members respectively; or they may each be formed as an integral end portion of the second or first tubular member.

The or each liner may be provided with stop means to engage the respective end portion of the sleeve within which the liner is received, to limit inward relative telescoping movement of the liner in the sleeve. The or each stop means may comprise an annular collar which engages the respective axiallyoutwardly-directed end surface of the sleeve.

The invention further comprises an end-toend assembly of tubular members comprising or including first and second tubular members coupled together in end-to-end relationship by a telescoping coupler as described above.

The present invention seeks to provide a means for allowing an assembly of preferably cylindrical tubular component casing sections and couplings to extend or contract in harmony with corresponding movement of the surrounding earth while maintaining the structural integrity of the casing assembly; its fluid seal (if present); and the axial and rotational alignment of adjacent casing sections. It is desirable that the means selected permit only a limited amount of longitudinal extension or contracting movement and that it includes positive stops at each end limit. The positive stop at the contraction end limit should preferably incorporate a large surface area of contact between adjacent elements in order to spread the compression load which accompanies full contraction of the casing assembly.

It is also desirable that the means selected be adaptable to a variety of configurations to allow flexibility in designing the casing assembly to meet the specific requirements of each sampling and measurement location. At least one configuration should preferably be a discrete component to allow casing assembly design modifications to be easily made in the field by utilizing a limited inventory of types of components.

The present invention with its various optional features as described above thus aims to provide means enabling these various desiderata to be achieved or approached to a greater or lesser extent.

According to a further optional feature of the invention, the or each liner may have internal grooves constituting a guideway for e.g. an instrument passed down the tubular assembly, the sleeve being ungrooved and providing a trackless area around the end of said liner. Where there are two liners, one in each end portion of the sleeve, this trackless area constitutes a gap between the liner ends.

Thus, when the coupler is at an extension between stop limits, this gap or recess which exists within the interior of the unit can be sensed as to location and length.

The invention may be carried into practice in various ways, but one specific embodiment thereof will now be described by way of example only and with reference to the accompanying drawings, in which: FIGURE 1 is a longitudinal view, partially in cross-section, showing a preferred form of telescopic coupler for tubular members; FIGURES 2, 3 and 5 are cross-sectional views taken in the several planes indicated as 2-2, 3-3 and 5-5 in Figure 1; FIGURE 4 is a fragmentary view in radial section on the line 4-4 in Figure 2; FIGURE 6 is a view, with portions broken away, of the telescoping coupler of Figure 1 installed between two tubular sections utilizing intermediate snap action couplings;; FIGURE 7 is a longitudinal exploded view of snap-action coupling and end-to-end disposed tubulars, with portions broken away and shown in section for convenience of illustration, for use as the snap action couplings of Figure 6; FIGURES 8, 9 and 10 are cross-sectional views 'taken in the respective planes 8-3, 9-9 and 10-10 of Figure 7; and FIGURE 11 is a longitudinal elevational view of the parts shown in Figure 7 assembled together, but not employed in the telescoping coupler of the present invention.

Figure 1 shows a double ended configuration of telescopic coupler embodying the invention which is constructed as a separate component and which can be inserted at one or each of several locations in a casing assembly. As best shown in Figure 6, this telescoping coupler 14 can be placed between a first tubular 10 and a second tubular 12 by use of the tubular snap action conduit couplings 28,30 which are fully disclosed in our aforesaid co-pending British patent application no: 8334246 filed (Case 5).A nipple 34 along with external stop collar 32, slots 38, springy segments 40 and annular segmented collar 36 are provided as formations at the outer end portion of each of a pair of liners 1 8,20, to be described,for the purpose of mating opposite ends of the telescoping coupler 14 to snap action couplings 28,30 which in turn mate to first and second tubulars 10,1 2 respectively. The ends of the tubulars 10. 12 are similarly formed with nipples, slots, springy segments and annular segmental collars, for coupling engagement in the outer end portions of the couplings 28,30.

The telescopic coupler, designated 14 as a whole, comprises a medial cylindrical'sleeve 16 of circular cross-section and in this instance tubular liners 18 and 20 also of circular section, stop collars 32,32, slots 24,24, and pins 26,26. Liners 18 and 20 slidably move in opposite end portions of medial sleeve 16 with their rotational alignment being maintained by the interaction between slots 24,24 in the walls of liners 1 8,20 and pins 26,26, carried by and projecting inwardly from the wall of sleeve 1 6. This interaction, in turn, maintains the alignment between longitudinal grooves 42 which are formed in the inner surfaces of liners 18 and 20. The longitudinal grooves 42 form a guideway for a device such as a torpedo inserted into the coupler, grooves 42 being aligned with similar grooves in the interiors of tubulars 10 and 12, and the sleeve 16 being ungrooved internally, forming a trackless area around the end of each liner. This trackless area or gap can be sensed, to provide an indication of the location of the coupler and the degree of its telescopic extension.

When the coupler 14 is at full extension, the areas of contact between the pins 26,26 and the outer directed ends of the slots 24,24 form bearing surfaces for the tension load through the telescoping coupler 14. Conversely, when the coupler 14 is at ful! contraction, the axially-inwardly directed end surfaces of the stop collars 32 will abut against the axiallyoutwardly directed end surfaces of the sleeve 16, and the two axially-inwardly directed end surfaces of the liners 18 and 20 will abut against each other to form a positive stop and to conjointly transmit the compression load through the telescoping coupler 14.

O-ring seals 50 between the liners 18,20 and the enclosing ends of the sleeve 16 prevent the ingress of water or cementitious grout when the tubular casing assembly is placed in the earth.

If it is desired to detach either of the tubulars 10 and 12 from the associated liner 18 or 20, since no adhesive is employed to effect the intercoupling of these parts this can readily be done by spirally cutting the sleeve of the coupling 28 or 30 and radially expanding the cut sleeve clear of the segmented collar 36 to release the interlock of the coupling,- without damage to the liner, as described in our aforesaid application no: 8334246 (Case 5).

It is to be understood that the invention is not limited to the specific features shown and described, since the means and construction herein disclosed and illustrated comprise a preferred form of putting the invention into effect and other embodiments of the invention are possible. For instance, it will be apparent to those skilled in the pertinent art that the tubulars 10 and/or 12 need not be detachably coupled to the coupler 14 by the respective coupling devices 28, 30 but rather the ends of the tubulars 10 and/or 12 may be adapted to provide liner ends similar to liners 18 and 20. These adapted liner ends, which may be integral parts of the tubulars, will then be inserted into respective open opposite ends of the sleeve 16 and located by the engagement of the sleeve pins 26 in the respective slots 24 of the adapted liner ends of the tubulars.

Other configurations are also possible. Thus a sleeve with a single open mouth which slidably receives an inserted liner, may be formed as an integral part of the end of a tubular. Alternatively, a sleeve, though formed as a separate part, may be formed at one end with a nipple 34, slots 38, springy segments 40 and an annular segmented collar 36 together constituting an end formation on the sleeve which will allow this modified sleeve to be detachably coupled directly to a tubular by means of a removable coupling device in the same manner as the liner 20 is coupled to the tubular 12 by the coupling device 30 as shown in Figure 6.With such an arrangement, the other end of this latter modified sleeve may slidably accept an inserted liner which is itself coupled to a second tubular by a removable coupling device in the same manner as the liner 18 is accepted in the sleeve 16 and is coupled by the coupling 28 to the tubular 10.

The specific embodiment of snap-action coupling described and illustrated in our aforesaid co-pending patent application no: 8334246 (Case 5) is hereinafter described and illustrated in Figures 7 to 11 of the accompanying drawings.

Referring to Figures 7 to 11, end portions of end-to-end disposed tubulars 1 OA and 12A are shown relative to a coupling sleeve 14A with which they are to be assembled so as to produce continuity throughout the tubulars 1 0A and 12A and others likewise assembled, for example to form a tubular casing for underground instrumentation.

Tubulars 1 0A and 12A have nipples 16A at each end, and internal grooves 18A extending from end to end and spaced about the inner surface of the respective tubulars. Usually four equi-spaced grooves 18A are provided per tubular as best seen in Figures 8 and 9. The nipples 16A are machined from and are of smaller diameter than the main bodies of the tubulars 10A and 12A and are separated from the main bodies of the tubulars by annular shoulders 20A. Each nipple 16A is divided by slots 22A into inwardly deflectable springy segments 24A, usually three in number as is best shown in Figure 8 and Figure 9. The ends of said segments 24A have a segmented shouldered collar extending circumferentially about the end of nipple 16A to form external lugs 26A that outstand and provide shoulders 28A.In the embodiment shown the lugs are formed by a decreased-diameter zone of the tubular 1 OA or 12A machined or otherwise formed between the shoulders 20A and 28A to a diameter smaller than the outer diameter of the tubulars. Each tubular end has an orientation notch 30A. The nipples may each be equipped with a groove and O-ring 48A positioned between the shoulder 20A and the inner ends of slots 22A.

Referring again to Figure 7, the coupling sleeve 14A has oppositely-open mouths 32A at its ends forming sockets into which the nipples 16A of tubulars are inserted for assembly of the coupling system. The internal diameter of each mouth 32A is substantially equal to the diameter of nipple 16A and somewhat less than the external diameter of the lugs 26A so that when the same are inserted into a mouth 32A the springy segments 24A are deflected inwardly as permitted by the slots 22A. The edge of mouth 32A has an inwardly directed bevel to facilitate entry of the nipple 16A which correspondingly has a chamfer around its end for the sane purpose.

Internally, coupling sleeve 14A has a cylindrical recess 36A which includes a doubleended orientating boss 38A mounted at a fixed location by means of pins 50A and/or adhesive in the middle lengthwise of the coupling 14A. Boss 38A, which has its interior surface flush with the inside diameter of the inserted nipple 16A, is adapted to cooperate with the orientation notches 30A in each end of tubulars 1 OA and 12A. As a nipple 16A is pressed into coupling 1 4A with its springy segments 24A deflecting inwardly, it eventually reaches the boss 38A and the recess 36A. When orientated so that one end of the boss 38A mates with orientation notch 3OA, the nipple 16A may be further inserted until its lugs 26A snap into recess 36A whereupon the inwardly-deflecting forces on segments 24A are relieved. Due to the inherent springy nature of the segments 24A, the shoulders 28A engage the internal annular shoulder 39A at the edge of the recess 36A. This provides an interlock that indexes (orientates) the tubulars and prevents withdrawal of the nipples 16A from within the coupling 14A, until and unless the sleeve is expanded radially or the segments are again deflected inwardly permitting their withdrawal. As previously indicated, the sleeve may be spirally cut from end to end, or otherwise cut to enable it to be radially expanded for this purpose.

Claims

1. A telescoping coupler for incorporation into an end-to-end assembly of tubular members, the coupler comprising an elongate sleeve disposed in use as an extension of an end of a first tubular member, the sleeve having an axial bore; a tubular liner received slidably within one end of the said bore; the liner being disposed in use as an extension of a second tubular member which is disposed in end-to-end relation to said first tubular member; and in which there is interengagement between the sleeve and the liner which permits limited longitudinal relative movement therebetween but prevents relative rotational movement therebetween.

2. The coupler of Claim 1 in which the said bore and liner are both of circular crosssection, and in which said interengagement is provided by an elongate slot and a pin entered into and slidable relatively to and along said slot, the slot and pin providing a sliding connection between the sleeve and liner.

3. The coupler of Claim 2 in which the slot is in the liner and the pin entered therein is carried by the sleeve and intrudes into said slot.

4. The coupler of any one of Claims 1 to 3, in which the liner has internal grooves constituting a guideway and the sleeve is ungrooved and provides around the end of said liner a trackless area.

5. The coupler of any one of Claims 1 to 4, including a second tubular liner slidably re-ceived within the other end of the bore of the sleeve, and disposed in use as an extension of the first tubular member, and in which there is interengagement between the sleeve and the second liner permitting limited longitudinal relative movement therebetween but preventing relative rotation therebetween, the arrangement permitting limited longitudinal relay tive movement between the adjacent ends of the two liners within the bore of the sleeve.

6. The coupler of Claim 5 in which the bore of the sleeve and the second liner are both of circular cross-section, and in which the interengagement between the sleeve and the second liner is provided by a second elongated slot and a second pin entered into the second slot and slidable relatively to and along that slot, the second slot and second pin providing a sliding connection between the sleeve and the second liner.

7. The coupler of Claims 2 and 6, in which both slots are in the respective liners and both pins are carried by the sleeve and intrude into the respective slots.

8. The coupler of any one of Claims 5 to 7, in which the first and second liners are both formed to be detachably connected in use respectively to the second and first tubular members by respective removable couplings.

9. The coupler of any one of the preceding claims, in which the or each liner has a stop means to engage the respective end portion of the sleeve within which the liner is received, to limit inward relative telescoping movement of the liner in the sleeve.

10. The coupler of Claim 9 in which the or each stop means is an annular collar which engages the respective axially-outwardly-directed end surface of the sleeve.

11. The coupler of any one of Claims 1 to 4, in which the liner is formed to be detachably connected in use to the second tubular member by a removable coupling.

12. The coupler of any one of Claims 1 to 4, in which the sleeve is detachably connected in use to the first tubular member by a removable coupling.

13. The coupler of any one of Claims 1 to 4, in which both the liner and the sleeve are each detachably connected to said second and first tubular members respectively by removable couplings.

14. A telescoping coupler for incorporation in an end-to-end assembly of tubular members substantially as specifically described herein and illustrated in the accompanying drawings.

15. An end-to-end assembly of tubular members comprising or including first and second tubular members coupled together in end-to-end relationship by a telescoping coupler as claimed in any one of the preceding claims.

16. An assembly as claimed in Claim 15 in which the telescoping coupler is as claimed in any one of Claims 1 to 10, and in which the or each liner is formed as an integral end portion of the second or first tubular member.