TUBULAR MEMBER THREAD PROTECTOR

TUBULA MEMBER THREAD PROTECTOR

This invention relates generally to a novel thread protector or threaded and other machined surfaces on the ends of tubular members. In particular, the in¬ vention relates to thread protectors adapted for pro- tecting threaded and machined surfaces on the e^'nd of oilfield tubular members against corrosion and damage during shipment and handling prior to their being threadedly coupled with other tubular members for use in an oil or gas well. Thread protectors have been used for many years to protect the ends of tubular members against damage during shipment and during handling on a drilling rig. Such protectors have been provided not only to protect against the corrosive atmosphere and materials which may be present during shipment and at a drilling location but also to protect the threaded and machined surfaces from damage caused by banging one tubular member against another, and the like. Such protectors have typically sealed at the end of the tubular member b butting against a machined surface or feature and likewise have sealed against some feature such as a shoulder or inclined sealing surface inwardly beyond the thread length.

There has developed a need however, for a thread protector which provides environmental and damage protection for a threaded end surface of a tubular member having no feature against which to seal. Thus, this invention aims to provide a thread protector for threaded tubular members which seals the threads and ma- chined surfaces of the tubular members by contacting and

OMPI sealing against the "as rolled" pipe body axially in¬ wardly beyond the thread length of the threaded surface.

The present invention therefore provides a thread protector for protecting threads and machined surfaces provided about the end of a tubular member, the threads of the tubular member extending axially along the end of the tubular member from an outward point near the end of the tubular member to an inward point defined by the thread length, said protector in- eluding a threaded body for threadingly engaging the threads at the end of the tubular member, first sealing means connected to the body for sealing about the end of the tubular member, and second sealing means connected to the body and having at least one resilient circum- ferential protrusion for circumferentially sealing about the tubular member inwardly beyond the thread length.

The resilient circumferential protrusion forming the second sealing means of the invention may be adapted to seal about the "as rolled" tubular body beyond the thread length or it may be adapted to seal about a machined cylindrical surface about the tubular body beyond the thread length. Where the tubular mem¬ ber has external threads, the threaded body means has a threaded interior surface adapted to engage with the tubular member threads and the first sealing means is an interior shoulder of the body means adapted to abut the end of the tubular member when the threaded body is fully engaged with the tubular member threads. Where the threads of the tubular member are internal threads, the threaded body means of the protector has a threaded exterior surface adapted to engage with the tubular member threads and the first sealing means is an ex¬ ternal shoulder adapted to abut the end of the tubular member when the threaded body means is fully engaged with the tubular member threads.

^■ HEm O PI Further features and advantages of the in¬ vention will be described with reference to several preferred embodiments of the invention which are de¬ scribed in more detail below together with the ac- companying drawings wherein:

Figure 1 illustrates the thread protector according to the invention adapted to seal about a pin or external threaded portion aid machined surfaces provided about the end of a tubular member; and Figure 2 illustrates an embodiment of the invention provided to seal about a box or internal threaded portion and machined surfaces provided within the end of a tubular member.

Figure 1 illustrates the embodiment of the thread protector according to the invention adapted to seal about threads 19 and machined surfaces provided about the exterior end surface of tubular member 18. The thread protector includes a cylindrical body 15 which has threads 20 provided about its interior sur- face which are adapted to at least partially engage the threads 19 on the end of tubular member 18. Although the threads illustrated may be typical API threads commonly used in oilfield tubular members-, the threaded surfaces 19 may be two step cylindrical threads or any other threaded surface. The threads 20 on the interior of the cylindrical body means 15 must of course be adapted to engage the particular kinds of threads 19 on the end of the tubular member 18.

A first sealing means 30 is provided for sealing about the end of tubular member 18. In the em¬ bodiment illustrated in Figure 1, the first sealing means 30 is an internal shoulder provided in the in¬ terior end of the threaded body means 15. Of course the first sealing means 30 may be advantageously pro- vided to seal against any end surface which may be ma¬ chined on the end of tubular member 18. For example, a reverse angle shoulder may be provided as the first

OMPI / sealing means 30 to cooperate with a reverse angle torque shoulder provided at the end of the tubular member 18.

A second sealing means 24 is provided on a circumferential extension 26 of the threaded body means 15. At least one circumferential protrusion 25 is provided for sealing against the "as rolled" exterior surface 32 of tubular member 18. Although a single cir¬ cumferential protrusion may seal the thread protector against corrosive fluids or atmosphere gases which could contaminate the threaded or other machined surfaces on the end of the tubular member, a plurality of circum¬ ferential protrusions or "teeth" are preferred for re¬ dundancy to assure that the threads are sealed. The circumferential extension 26 is provided axially in- wardly beyond the thread length L of the threaded por¬ tion of the threaded body means 15 as illustrated in Figure 1.

Preferably, the threaded body means 15 is fabricated from a resilient plastic such as urethane. The circumferential extension 26 which is integral to the threaded body means is likewise preferably constructed of the resilient plastic urethane. An outer jacket of metal 16 is provided to surround the threaded body means 15 providing rigidity and protection to the threaded body means 15 constructed of resilient plastic. Pref¬ erably the outer jacket 16 extends axially inwardly approximately to the length L of the thread length but does not extend to the circumferential extension 26 on which the circumferential sealing means 25 ^'.is provided.^' The absence of a steel jacket about the circumferential extension 26 assures that the circumferential extension 26 and the circumferential protrusions 25 may flex about the outer surface 32 of tubular member 18 as the protector means 10 is threadedly applied to the end of tubular mem- ber 18. Although the preferred embodiment of the in¬ vention calls for metallic jacketing of the exterior of the threaded body means 15, including a bottom closure 17, a metallic insert may be embedded for rigidity and protection with in threaded body means 15 either in sub¬ stitution for or in addition to the outer jacket 15. A hole may also be provided in the end of bottom closure 17 to provide air within tubular member 18, thereby pre¬ venting moisture from corroding the inside of member 18. Projections or geometrically shaped holes may also be provided in bottom closure 17 to cooperate with tools for mounting and unmounting the protector 10 about the end of tubular member 18.

Figure 2 illustrates an alternative embodiment of the invention in which a thread protector 10 ' is adapted to protect a box or internal thread 51 provided within the end of tubular member 19. As illustrated in Figure 2, the threaded and machined portion of the box threads 51 extend axially inward a thread length L* at the end of tubular member 19. As illustrated, a ma¬ chined sealing surface 52 may be provided on the ex¬ treme end of tubular member 19 and a machined surface 50 may be provided inwardly of the thread length L* about the circumferential interior of the tubular member 19. In the embodiment of the invention illustrated in Figure 2, the thread protector 10' includes a threaded body means 60 on which external threads 62 are provided to threadedly engage the particular internal threads 51 provided on the end of tubular member 19. (Although two step cylindrical threads are illustrated, other thread types may of course be used, such as API threads) . .An external shoulder 31 is provided on the outer end of the threaded body member 60 to abut against the end of the tubular member 19. As discussed above with regard to the embodiment of the invention illustrated

OMPI in Figure 1, the sealing means 31 may be provided to mate with the end surface of tubular member 19 such as a reverse angle torque shoulder.

A second sealing means 56 is provided on a circumferential extension 53 of the threaded body means 60. At least one outwardly facing circumferential protrusion 55 is provided for sealing against the in¬ terior cylindrical machined surface 50 of tubular member 19. Although a single circumferential protrusion may seal the thread protector against corrosive fluids or atmospheric gases which could contaminate the threaded or other machined surfaces within the end of the tubu¬ lar member, a plurality of circumferential protrusions or "teeth" are preferred for redundancy to assure that the threaded surfaces are sealed. The circumferential extension 53 is provided axially inwardly beyond the thread length L* of the threaded portion of threaded body means 60 as illustrated in Figure 2.

Preferably, the threaded body means 60 is fabricated from urethane as is the extension 53. An inner jacket of metal 61 is provided to surround the in¬ terior of threaded body means 60. Preferably, the inner jacket 61 extends axially inwardly approximately to the length L' of the thread length, but does not extend to the circumferential extension 53 on which the circum¬ ferential sealing means 56 is provided. The absence of a steel jacket about the circumferential extension 53 as¬ sures that the circumferential extension 53 and the cir¬ cumferential protrusions 55 may flex about the machined- surface 50 of tubular member 19 as the protector means 10* is threadedly applied to the end of tubular member 19. Extension member 53 and resilient sealing means 56 may alternatively be provided to seal about the un- machined interior surface 54 of tubular member 19. A cylindrical metallic insert may be embedded within threaded

^•^ B E

OMPI body means 60 in substitution for or in addition to the metallic inner jacket 61.

Various modifications and alterations in the described thread protector will be apparent to those skilled in the art from the foregoing description which does not depart from the scope of the invention.

O PI