Kawasaki Steel Corporation

Hunting Oilfield Services (uk) Ltd.

Geoffrey C Dearden

Donald N Jones

Katsuo Ueno

Edward J Speare

A pipe connector comprises an internally threaded female member and an externally threaded male member for threaded engagement in the female member. When the members are fully engaged together, an axially and radially directed surface at the free end of one of the members, e.g. the male member, is abutted against a corresponding surface on the other member, e.g. the female member. The surface comprises radially inwardly and outwardly curved surface portions which are relatively dimensioned to be a radial force fit such as to cause deflection of the end portion of the free end of the male member away from the female member as the members are brought into full engagement to bring the surfaces into full engagement.

Pipe connectors

A connector, for example for connecting pipe sections, comprises a female member having threaded internal circumferential surfaces at each end, for engagement with a pair of male members each of which is provided with a threaded external circumferential surface. Each male member is provided with an annular nose having an axially directed primary sealing surface for sealing abutment with the primary sealing surface of the other male member, and a circumferential secondary sealing surface for sealing against a secondary sealing surface on the female member. The sealing surfaces being initially shaped so that when the noses are initially brought into contact there are progressively widening axial and radial gaps therebetween which are closed by deformation of the noses when the members are fully engaged together.

Pipe connector

A connector, for example for connecting a tubular member such as a pipe, comprises a male member which has an external frusto-conical surface provided with a thread and a female member having an internal frusto-conical surface provided with a thread for engagement will the thread of the male member. The members are provided with generally radially directed sealing surfaces which are brought into sealing abutment under an axially directed compressive force when the members are fully engaged together. To improve the loading of the threads of the members on engagement of the members and on application of a tensile load to the engaged members, the axial thickness of the thread of at least one of the members in one or both of the portions of the thread adjacent the ends thereof is reduced to increase the flexibility of the thread and therefore reduce the load sustaining ability of the thread. Specifically the reduction in the axial thickness is greatest at the end of the thread and progressively decreases away from the end. This reduction is achieved by providing threads having leading flanks with a constant pitch and trailing flanks whose pitches are varied to provide the required variation in axial thickness. In the preferred embodiment, the thread of the male member adjacent its free end is reduced in axial thickness and the thread of the female member adjacent its free end is reduced in axial thickness.

A connector, for example for connecting a tubular member such as a pipe, comprises a male member which has an external frusto-conical surface provided with a thread and a female member having an internal frusto-conical surface provided with a thread for engagement with the thread of the male member. The members are provided with sealing surfaces which are brought into sealing abutment under an axially directed compressive force when the members are fully engaged together, as a result of which one member, as shown in FIG. 3 the male member, is partly compressed and the other member, as shown in FIG. 3 the female member, is partly tensioned. To improve the loading of the threads of the members when the members are fully engaged together and under an applied tensile load, the threads of the members are divided into three portions, an intermediate portion and end portions, the pitches of the threads in the three portions are the same and constant throughout their axial extents but the relative phases of the threads in the end portions differ. Specifically the phase angle of the threads in the intermediate portion is the same. In the end portion adjacent the sealing surfaces, the phase of the thread of the member (which was placed under compression during make-up) is advanced relative to that of the other member, and in the other end portion the phase of the thread of the other member is advanced relative to that of the one member.

A connector, for example for connecting a tubular member such as a pipe, comprises a male member which has an external frusto-conical surface provided with a thread and a female member having an internal frusto-conical surface provided with a thread for engagement with the thread of the male member. The members are provided with sealing surfaces which are brought into sealing abutment under an axially directed compressive force when the members are fully engaged together, as a result of which one member is partly compressed and the other tensioned. To improve the load distribution along the threads of the members, the pitch of the thread is varied along the axial length of the threaded surfaces. Specifically the surfaces are divided into three portions, an intermediate portion in which the pitches of the threads of the members are the same, and end portions at either end of the intermediate portion, in which the pitches of the threads differ. In the end portions closest to the sealing surfaces, the pitch of the thread of the one member, which is compressed during full engagement of the members, is greater than the pitch of the thread of the other member, and in the other end portion the pitch of the thread of the one member is smaller than the pitch of the thread of the other member.

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Bedford, United Kingdom

Geoffrey C Dearden