WO2001033033A1

WO2001033033A1 - A feeder for feeding a pipe or rod string

Info

Publication number: WO2001033033A1
Application number: PCT/NO2000/000335
Authority: WO
Inventors: Ola Lunde
Original assignee: JM Consult AS
Current assignee: JM Consult AS
Priority date: 1999-11-05
Filing date: 2000-10-11
Publication date: 2001-05-10
Anticipated expiration: 2002-05-05
Also published as: NO310691B1; NO995413L; AU1064501A; NO995413D0

Abstract

A feeder for feeding a pipe or rod string (R2, S) of equal outer diameter varying from string to string, or a corresponding string of jointed pipe or rod lengths wherein the joints (S) form thickenings on the remaining part (R2) of the string. The feeder comprises at least two pairs of feeding rollers (10a, 10b and 12a, 12b). The two feeding roller pairs are spaced from each other in the feeding direction, and the rollers are rotatable and motorized. The driven rotation of the feeding rollers combined with friction established between feeding rollers and pipe/rod string (R2, S) causes the feeding. In order to let through the string-thickening joints (S), simultaneously providing a continuous, uninterrupted feeding of the string (R2, S), one feeding roller (10a, 12a) in each pair (10a, 10b and 12a, 12b) is pivotally mounted in a direction away fron the other feeding roller (10b, 12b) in each pair, said other feeding roller (10b, 12b) in each pair being placed on a common carrier plate (44) which is pivotal about a pin (45), the axis thereof being parallel to the rotational axes (14a, 14b, 16a, 16b) of the feeding rollers. Upon the impact of a joint (S) or the feeding-in end of a new string having a larger outer diameter (than the previous string) against the feeding rollers in one pair at a time, the rollers swing away from each other in order to open the pressure nip and let/feed the joint (S) or the new string through.

Description

A FEEDER FOR FEEDING A PIPE OR ROD STRING

This invention relates to a feeder for feeding a continuous pipe or rod string without jointing thickenings or, respectively, a corresponding string of jointed pipe or rod lengths wherein the joints form thickenings on the string, said feeder in addition being of the kind as defined in the preamble of claim 1.

Often, feed devices of this type are designated "feeders" and serve to feed continuous pipe or rod strings without jointing thickenings, e.g. coiled tubings, of mutually varying outer diameters or, respectively, a corresponding string of interconnected pipe or rod lengths, e.g. metal pipe lengths or glass fibre rods, wherein the joints form thickenings on the string, said feeder comprising at least two pairs of rotatable driven feed rollers, wherein the feed roller pairs are spaced from each other in the feed direction, and wherein the rotatable driven feed rollers in each pair form a pressure nip, and the rollers together define a through-going passage through the feeder, and wherein^" the rotation of the feed rollers causes the feeding. Such feeders are used for feeding coiled tubing of various dimensions or e.g. a long rod of joined glass fibre poles which at the end thereof is provided with e.g. a logging tool or another instrument to be run down into a well and up therefrom.

In order to let joint portions constituting lateral thickenings on the rod or pipe string or a larger coilable tubing dimension than the previous one pass in a suitable way through the feeder, simultaneously as at least one of its roller- or wheel-shaped feed means cooperating in pairs, at any time may exert the necessary or desired clamping force around the string, suitable adaptations and additional precautions must be taken in connection with the feeder.

The state of the art is i.a. represented by GB A 2,180,869, US 2,262,364 and US 4,903,822.

In the feeder shown and described in US 4,903,822, one can not achieve that a string having joint thickenings is pulled efficiently forward. This is due to the fact that each feed roller in two pairs of cooperating feed rollers is disposed at one of the four ends of a scissors-like mechanism having two crossing beams wherein one common pivot point is located in the crossing point which is spaced at the same distance from the individual rotary axis of each feed roller. At any time, this necessitates an identical pressure nip at the two feeding roller pair. henever a joint thickening is between two feed rollers forming one feed roller pair, and the pressure nip there has a maximum opening, the aperture at the other pressure nip must also be opened maximally, and a pipe string portion passing between the feed rollers forming said other pressure nip can, therefore, not be subjected to the intentional combined clamping and feeding force.

The feeder comprises two pairs of rotatable roller- or wheel- shaped feeding means, individual wheels in the pair being adapted to rotate in opposite rotational directions, a pipe or rod string to be fed from left to right requiring that the feeding pair of rollers rotates such that an upper feed means rotates counter-clockwise, a lower feed means in said feed means pair rotating clockwise.

A resilient or flexible clamping means provides possibilities of compliance for the individual feeding means of the feeding means pairs whenever the string's thickened joint portions pass, while the other feeding means pair acts on the pipe or rod system when the direction of linear conveyance is away from (or towards) e.g. an accommodating drum on which the jointed pipe is coiled.

The two feeding roller pairs are disposed at a comparatively short distance from each other, as counted in the feed direction of the string, and immediately after the feed rollers of the first pair have yielded resiliently off in a direction away from each other, in order to let a joint portion of the pipe or rod string slip past, while the feeding rollers of the other, downstream feeding roller pair which, thereby, took care of resting clampingly, feedingly against the non-joint portion situated in front thereof, now must be adapted to let said joint portion by. At the same time, the upstream roller pair enters into feeding contact with the non-joint portion upstreams of said joint portion.

It is the thickening itself on the string formed by each joint that effects the compliance off or swinging away of the first upstream feeding rollers in directions away from each other. As soon as the joint portion has passed one feeding roller pair, the rollers of the respective pair are automatically returned resiliently to their original positions wherein the spacing between the rotational axes of the rollers is minimum.

A corresponding case constitutes feeding a string exhibiting a larger outer diameter than the minimum outer diameter that is absolutely necessary in order to feed such a string through the feeder when the feeding rollers in each pair take original positions (shortest possible distance between opposing roller circumferences, corresponding to smallest nip, i.e. the initial nip).

One feeding roller in each pair may have a stationary rotational axis in relation to a pivotable carrier plate, while the other roller in the respective pair is pivotable around a pivot axis parallel to the rotational axis, so that the rollers in each pair may move away from each other until they are mutually spaced a distance corresponding to that a friction-creating, driving circumferential face resting against the joint.

In a practical embodiment, one feeding roller in each pair may be carried at a middle portion by a curved or angled arm, on one end thereof being rotatably disposed at a common, intermediate link for the two curved or angled arms, the other end being articulated to one end of a flexible longitudinally variable means .

When such a pivotable feeding roller in the upstream roller pair, i.e. the roller pair with which the feed-in end - of a joint-free string having an outer diameter exceeding smallest diameter (corresponding to initial position) or a joint portion on the pipe or rod string - first comes into contact - of the feed-in end respectively the string-thickening joint portion becomes pushed forwardly in the direction of feeding, the curved or angled arm's turning point for the feed roller will be moved in the same direction, so that the effected swinging of the angular arm about its pivot point causes a swinging-up or lifting of the upper feeding roller, so that joint portion of the string gets space to pass between the two feeding rollers in said upstream roller pair.

The above-mentioned longitudinally variable means may, advantageously, consist of a pressurized fluid operated piston cylinder having a circuit closed per se, to which is coupled an accumulator, preferably in the form of a so-called gas-spring. With a gas-spring is meant a container internally divided by means of a diaphragm attached along the periphery, defining a closed chamber containing a compressible gas at one side thereof and a chamber in the form of a cavity having an inlet/outlet for e.g. hydraulic oil at the other side thereof.

The flexible, somewhat resilient longitudinally variable means may, in principle, be constituted by an elongated body of rubber-elastic material or, respectively, by a strong, shape permanent screw spring; in both cases formed with two axial ends of which each one can be connected articulately to the outer end of a curved arm of their own.

Whenever a joint portion passes the feed rollers in a pair, the upper feed roller is_ lifted, such as mentioned, and because of the intermediate coupling of the angular arm to a hydraulic piston cylinder, the length of stroke thereof is reduced.

To one feeding roller in each pair, a hydraulic drive motor may be assigned. The transmission mechanism may comprise concentrical gear wheels, one on each feeding roller shaft, as well as two idle wheels in mutual engagement, one of which is meshing with the two upper gear wheels, the other one being in engagement with the two lower gear wheels, engine- driven separately.

More specifically, a feeder according to the present invention is characterized by the features as defined in the characterizing clause of claim 1. Advantageous, yet subordinate features unitary with the invention of claim 1, supporting the function of the subject matter in accordance therewith, are defined in the following, dependent claims 2-8.

In the embodiment of a pipe or rod string feeder of the relevant kind as described in the following, it has been assumed, in the interest of simplicity, that the path of movement of said pipe or rod string through the feeder is directed horizontally.

Non-restricting examples of preferred embodiments are further explained in the following, reference being made to the accompanying drawings, wherein:

Figure 1 shows a side elevational view of a feeder in accordance with the invention, where said flexible, longitudinally variable clamping device of the feeder in the form of a hydraulic piston cylinder is assigned a so-called gas-spring, and where the feeder takes initial position adapted to the feeding through of a horizontally extending pipe or rod string portion having a minimum outer diameter and being without radially projecting joint portions;

Figure 1A corresponds to figure 1, but shows feeding rollers and means coupled thereto upon the feeding through of a joint-free pipe string, e.g. a coiled tubing, having a somewhat larger outer diameter than the pipe string or coiled tubing;

Figure 2 shows an end view of the feeder of figure 1, as seen from the right end in figure 1, but during the feeding through of a pipe or rod string having radially projecting joint portions between joined pipe or rod lengths, and where it is assumed that a joint portion S is positioned between the pairs of feeding rollers, see figure 4;

Figure 3 is a side elevational view corresponding to figure 1, where a string-thickening joint S on the pipe or rod string in figure 2 has entered into the pressure nip of the upstream feeding roller pair and pressed the two feeding rollers thereof, an upper and a lower one, away from each other, wherein the two lower feeding rollers in each pair are disposed on a pivotable carrier plate, the horizontal pivot axle being formed by a trunnion at the top of a stationary post, and wherein the total length of the hydraulic piston cylinder is shortened in relation to figure 1, and wherein the gas-spring assigned thereto secures correct bias in the pivotable feeding roller included in each pair of feeding rollers and connected to the piston cylinder;

Figure 4 corresponds to figure 3, but in figure 4 the feeding rollers take the initial position, corresponding to the position taken in figure 1, for feeding through a joint-free pipe or rod string portion;

Figure 5 shows a perspective view of the feeder of the invention upon the feeding through of a string having radially projecting joint portions S according to figures 2-4.

Reference indications 10a and 10b denote two feeding rollers in a first, upstream feeding roller pair, relatively movable in a vertical direction, wherein the lower feeding roller 10b in the pair having a stationary rotational axis 14b, while the rotational axis 14a of the upper feeding roller 10a is movable up/down in a manner further described later. In general, the downstream feeding roller pair 12a, 12b is disposed in the same way as the upstream feeding roller pair 10a, 10b.

Based on a pipe or rod string feeding direction from left to right in figure 1, the two upper feeding rollers 10a and 12a are to rotate counter-clockwise, the two lower feeding rollers 10b, 12b should have the opposite rotational direction, i.e. clockwise. All rotational directions are marked at the respective feeding roller and denoted at P.

The two lower feeding rollers 10b and 12b are driven by a hydraulic motor 18 respectively 20 of their own, the output shaft thereof being coupled to the associated feeding rollers drive shaft (21 for the feeding roller 12b in figure 2 where the other drive shaft etc. is hidden).

In figure 1A, a joint-free pipe or rod string Ri having a larger diameter than the string R in figure 1 is fed through the feeder. Thus, during the feeding to the right, the feeding-in end (the right hand end in figure 1A) of the string Rxhas swung upwardly the upper feeding roller 10a of the upstream feeding roller pair 10a, 10b and pressed the lower feeding roller 10b in said pair downwardly during the rotation of the plate 44 (see figure 3, string having a joint S) in order to widen the nip between the upstream feeding roller pair 10a, 10b. Upon contact with the downstream feeding roller pair 12a, 12b, the feeding-in end of the string Ri swings upwardly an upper feeding roller 12a and presses downwardly the lower feeding roller 12b. Participants in these movements of the feeding rollers 10a, 10b, 12a, 12b in order to adapt to the larger thickness of the pipe or rod string R_x, are the piston cylinder 34 (which, according to figure 1A, has a shorter axial length than in figure 1), the articulated angle levers 30, 32 and the pivotable plate 44.

In the following description, the feeder is explained in association with a special case, i.e. when feeding through a string of jointed pipe or rod lengths, where the joints S form thickenings on the string R₂.

Figure 2 shows that two cooperating feeding rollers 12a, 12b are formed as rope pulleys having a concavely curved, 360° circumferentially extending middle groove which, in cross- section, follows a circle bow less than 180° with a radius corresponding to half the outer diameter of the pipe or rod string R₂ between joint portions S.

On the shaft 21 between the motor 20 and the feeding roller 12b (and between the motor 18 and the -feeding roller 10b) is wedged a gear wheel or a pinion gear 24b, and between the motor 18 and the feeding roller 10b a gear wheel or pinion gear 22b. Each of these toothed wheels 24b, 22b meshes with a toothed idle wheel 28, the gear wheels 22a, 24a being placed on one of the rotary feeding roller shafts of their own, each of the last-mentioned gear wheels meshing with a second idle wheel 26 which, in its turn, meshes with the idle wheel 28.

Each of the two upper feeding rollers in the upstream feeding roller pair 10a, 10b and the downstream feeding roller pair 12a, 12b is pivotally suspended in a rotational axis position 14a and 16a, respectively, from an angle lever (curved arm) 30, 32 approximately in the middle thereof.

At its upper end, the angle lever 30 is articulated to one axial end of a flexibly resilient, longitudinally variable clamping means 34, here shown in the form of a hydraulic piston cylinder, the other axial end thereof being articulated to the upper end of the other angle lever 32.

The lower end of the angle lever 30 and 32 is articulated to each other about a turning axis 36 also forming rotational axis for the upper idle wheel 26.

Figure 3 shows, together with figure 1, the swinging possibilities for the upper feeding roller 10a in the upstream feeding roller pair 10a, 10b as a result of a lifting force (from the joint S), while the lower feeding roller 10b serves as a downward movement restricting means for the joint S, thus reducing the piston stroke of the piston cylinder 34.

To the piston cylinder 34, as known per se, is coupled a gas- spring 38 of known construction. In this mutual position for the feeding rollers 10a and 10b in the upstream feeding roller pair 10a, 10b, the joint S have space to pass between these feeding rollers 10a and 10b in case outer circumferential portions of the feeding rollers are spaced further from each other than the outer diameter of the joint portion S, exceeding the remaining pipe or rod string's outer diameter in such a degree as corresponds to the upper movably mounted feeding roller's 10a swinging extent away from the lower feeding roller 10b in the pair, wherein the rotational axis 14b is stationarily positioned on a pivotable carrier plate 44. The carrier plate 44 is pivotable about a pin 45, the axis thereof being horizontal and which is disposed at the top of an upright 41 of a machine frame member 42.

The upper, movably mounted feeding roller 12a in the downstream pair 12a, 12b has a corresponding swinging pattern as the upper feeding roller 10a in the upstream feeding roller pair 10a, 10b, the feeding roller 12a being lifted by the joint S simultaneously as the lower feeding roller 12b is forced downwardly in a corresponding degree upon the swinging of the carrier plate 44.

Likewise, the rotational axis 14b of the lower feeding roller 10b is stationarily positioned in relation to the pivotable carrier plate 44, and the feeding roller 10b, thus, following the carrier plate's 44 swings which actually are caused by one or the other of the lower feeding rollers 10b or 12b when one of these is influenced by the joint S of the pipe or rod string as it strikes against the respective feeding roller pair.

In figure 4, the feeding rollers 10a, 10b, 12a, 12b take the initial positions with the same distance between the rotational axis 14a and 14b respectively 16a and 16b in each pair, for feeding passage of an evenly thick pipe or rod string portion R₂. Otherwise, this figure does not show any details beyond those appearing from figure 3. The gas-spring 38, known per se, serves also here as an accumulator for the hydraulic piston cylinder 34.

In figures 1 and 4, the feeding rollers 10a, 10b and 12a, 12b take initial positions for feeding-in/-through of joint-free pipe or rod string portions R of minimum outer diameter. In this situation, the pipe or rod string is fed with an even, rectilinear speed through the feeder.

According to the invention it is maintained a substantially continuous feeding process also when the string-thickened joint enters one or the other clamp nip. Reference is made to figure 3, where the joint S has arrived in between the feeding rollers 10a, 10b and lifted the roller 10a for swinging the lever(s) 30 and reducing the piston stroke of the cylinder 34, simultaneously as the joint S has pressed the roller 10b down and, thus, effected swinging of the carrier plate 44 around the horizontal axis of the stationary pin 45. The gas-spring 38 provides for a reduction of the stroke thereof without causing any substantial clamp force and/or pressure increase.

According to figures 4 and 5, the joint portion S is fed such forwardly that it is positioned approximately in the middle of the length of the feeder, i.e. outside both pressure nips. Thus, both feeding roller pairs have taken initial positions as set forth in figure 1, but when the ^"joint S on the string R₂ is fed an other small distance to the right, it will simultaneously strike against the outer circumferential portions of the feeding rollers 12a and 12b in the downstream feed roller pair and, thus, force the upper feeding roller 12a up and the lower feeding roller 12b down. The pipe or rod string R₂,S is, thus, fed through the feeder axially, i.e. such that the longitudinal axis is not displaced up or down during the passage through the feeder.

Claims

C l a i m s

1. A feeder for feeding a continuous pipe or rod string (R; Ri) without joint thickenings respectively a corresponding string (R₂,S) of joined pipe or rod lengths where the joints (S) form thickenings on the string (R₂), said feeder comprising at least two pairs of rotatable, driven feeding rollers (10a, 10b and 12a, 12b), wherein the feeding roller pairs are spaced in the feeding direction, and wherein the rotatable, driven feeding rollers (10a, 10b and 12a, 12b) in each roller pair form a pressure nip, said pressure nips together defining a through-going passage through the feeder, and wherein the rotation of the feeding rollers causes the feeding, and wherein at least one feeding roller (10a, 12a) in each pair (10a, 10b and 12a, 12b), as referred to an initial position for each feeding roller pair, is movably disposed in a direction away from the other feeding roller (10b respectively 12b) in the respective pair, c h a r a c t e r i z e d i n that the o respective movable feeding roller(s) (10a, 12a) is mounted and adapted to be activated for carrying out this movement away from the other feeding roller (10b respectively 12b) in the pair when - into the pressure nip of the respective feeding roller pair - a string 5 portion (a joint S or e.g. an evenly thick coiled tubing) having an outer diameter exceeding the distance between the feeding rollers (10a, 10b and 12a, 12b) in said initial position is in the process of being fed, at least one feeding roller (10a, 12a) in each pair 0 (10a, 10b and 12a, 12b) being pivotal on a pivot axis parallel to the rotational axis (14a respectively 16a) of the respective feeding roller (10a, 12a), said pivot axis (14a, 16a) being spaced from each other in the feeding direction, and that the pivotal feeding roller(s) (10a, 12a) in each pair (10a, 10b and 12a, 12b) is (are) adapted to be swung towards said initial position upon a relative movement as soon as those forces acting thereon and causing the distension of the pressure nip, ceases.

2. A feeder as defined in claim 1, c h a r a c t e r i z e d i n that the relative movability of the feeding rollers within each feeding roller pair (10a, 10b and 12a, 12b) is mutually independent on each other, so that the pressure nip of one feeding roller pair (10a, 10b), at any time, may operate with a dimension of through-going opening differing from the dimension of through-going opening with which the other feeding roller pair (12a, 12b) operates in the pressure-nip, as referred to the same moment during the feeding operation.

3. A feeder as defined in claim 1, c h a r a c t e r i z e d i n that pivot axis of two adjacent, pivotally disposed feeding rollers (10a, 12a) indirectly are interconnected by means of flexible, longitudinally variable, power-exerting means (34) adapted to try to maintain the maximum functional length thereof and to press the pivotal feed rollers (10a, 12a) to initial positions where each pivotal feeding roller together with the other feeding roller (10b respectively 12b) of the respective feeding roller pair forms a pressure nip accommodated for feeding forwards a string o portion (R) but, possibly, adapted to allow axial shortening in order to open the respective pressure nip sufficiently to let a string joint (S) pass through.

4. A feeder as defined in claim 3, c h a r a c t e r i z e d i n that the two feeding rollers (10b, 12b) which are not pivotally disposed, are mounted on a carrier plate (44) pivotal about a pin (45) the axis thereof being parallel to the rotational axes (14b, 16b) of these feeding rollers (10b, 12b).

5. A feeder as defined in claim 3, c h a r a c t e r i z e d i n that each pivotal feeding roller (10a, 12a) is rotatably mounted in a middle area of an angle lever (30, 32) which with one end thereof is articulated to one axial end of said flexible, longitudinally variable, power-exerting means (34) extending between said angle lever ends in an orientation substantially parallel to the feeding direction of the pipe or rod string (R; Ri; R₂,S) through the feeder, the other ends of said angle levers (30, 32) being mutually articulated (36).

6. A feeder as defined in any one of the preceding claims, c h a r a c t e r i z e d i n that a gear wheel (22a, 22b, 24a, 24b) has been attached to the drive shaft of each feeding roller (10a, 10b, 12a, 12b), at least one gear wheel being motor-driven, one driven feeding roller's (10b, 12b) gear wheel (22b, 24b) in each feeding roller pair (10a, 10b and 12a, 12b) being in driving power transferring mesh with an intermediate gear wheel (28) being in power transferring mesh with a toothed intermediate wheel (26) with which the gear wheels (22a, 24a) of the two other^" feeding rollers (10a, 12a) mesh, and which is rotatably mounted on the pin joint (36) interconnecting the said other ends of the angle levers (30, 32).

7. A feeder as defined in any one of the preceding claims, c h a r a c t e r i z e d i n that said flexible, longitudinally variable, power-exerting means (34) is a pressurized fluid operated piston cylinder which, preferably, is assigned a gas-spring (38).

8. A feeder as defined in claim 7, c h a r a c t e r i z e d i n that the piston cylinder (34) at its closed cylinder end is pivotally suspended from said pivotal carrier plate (44) about an axis (46) which i.a. is parallel to the various, mutually parallel rotational axes (14a, 14b, 16a, 16b) of the feeding rollers.