DESCRIPTION;

This invention relates to a ball valve for pipelines.

The object of the invention is to facilitate the servi¬ cing of the ball valve so as to minimise the period during which the valve is out of service and the costs associated therewith.

According to the invention there is provided a ball valve comprising an outer housing in the form of a substantially cylindrical pot closed at one axial end, open at the other axial end and having two diametrically opposite openings in the cylindrical wall of the housing, the radially outer sides of the openings being adapted for connecting the housing into a pipeline and flat annular seat faces being formed around the openings at the radially inner sides thereof, an annular wedge- shaped ring located against each one of said seat faces with the deepest dimension of the ring nearest the closed end of the outer housing, an inner housing in the form of a substan¬ tially cylindrical pot closed at one axial end, open at the other axial end and having two diametrically opposite openings in the cylindrical wall of the inner housing, flat annular seats being formed around the openings at the radially outer sides thereof, an annular wedge-shaped adaptor having an annular shoulder located against each one of said seats, a cylindrical neck projecting through the opening radially in¬ wardly, and an inclined annular surface on the side of the adaptor remote from the neck with the shallowest dimension of the adaptor nearest the closed end of the inner housing, a ball member mounted for rotation within and about the axis of the inner housing, the ball member having a diametrical through passage and a rotatable operating stem journalled in a remov¬ able bonnet closing the open end of the inner housing, the projecting cylindrical neck of the adaptor

housing annular seal means resiliently engaging the ball member, the inner housing, the adaptors, the ball member " and operating stem and the annular seal means being insertable into and withdrawable as a subassembly from the outer housing through its open end, the subassembly being insertable into the outer housing to a fully assembled conditon therewith where the inclined annular surface of each adaptor is wedgingly engaged with one of said annular wedge-shaped rings and the ball member is rotatable between an open position where its through passage is aligned with the aligned openings in the outer housing and the adaptors and a closed position where the openings are blocked by the ball member.

With the invention the outer housing can be left connected in the pipeline during servicing. After the subassembly has been withdrawn the annular wedge-shaped rings can be easily replaced if necessary. In order to inspect the ball member and the annular seal means therefor it is only necessary to withdraw the adaptors outwardly from the withdrawn subassembly. The valve of the invention also complies with BSI and API requirements. In firesafe applications the invention may embody the sealing arrangements disclosed in European (UK) Patent Specification No 0027048 and complies with BS 5146 firesafe requirements and equivalent API firesafe requirements.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:-

Fig. 1 is an axial sectional view of a fully assembled valve embodying the invention;

Fig. 2 shows a detail of Fig. 1 to an enlarged scale; and

Figs. 3a and 3b are respect vely a sectional side view and an end view of an annular wedge-shaped ring used in the valve.

The ball valve comprises an outer housing 1 n the form of a substantially cylindrical pot closed at one

-V axial end by a bottom wall 2 and open at the other axial end at the top. The housing 1 has two diametrically opposite openings 3 in the cylindrical wall 4 of the housing 1 and the radially outer s des 5 are adapted for connecting the housing into a pipeline. Around the openings 3 at the radially inner sides thereof there are formed flat annular seat faces 6 against each of which there is located an annular wedge-shaped ring 7 with the deepest dimension nearest th.e wall 2.

One of the rings 7 is shown in greater detail in F g. 3. The ring 7 is formed with a face 30 for engagement with the seat face 6, the face 30 being provided with axial grooves 31 for receipt of 0-rings (not shown) . The opposed face 32 is angled to provide a wedge angle A of a few degrees.

Reverting to Fig. 1 , a subassembly comprises an inner housing 8 in the form of a substantially cylindrical pot closed at one axial end by a bottom wall 9 and open at the other axial end at the top. The housing 8 has two diametrically opposi e openings 10 in the cylindrical wall 11 of the housing 8. Flat annular seats 12 are formed around the openings 10 at the radially outer sides thereof and an annular wedge-shaped adaptor 13 has an annular shoulder 14 located against each one of the seats 12. A cylindrical neck 15 of the adaptor 13 projects through each opening 10 radially inwardly. Remote from the neck 15 the adaptor 13 has an inclined annular surface 16 and the shallowest dimension of the adaptor 13 is nearest the wall 9.

The subassembly also comprises a ball member 17 mounted for rotation within and about the axis of the housing 8. The ball member 17 has a diametrical through passage 18 and a rotatable operating stem 19 journalled in a removable bonnet 20 closing the top of the housing 8. Opposite the stem 19 the ball member 17 has a recess 21 rotatably receiving a trunnion 22 projecting upwardly from the wall 9. The ball member 17 is resi liently

engaged by annular seal means 23 housed in the projecting cylindrical neck 15 of each adaptor 13.

Fig. 2 shows part of the adaptor 13 in greater detail. The seal means 23 comprises a seal holder 33 carrying a seal 34 biased into engagement with the ball member 17, eg. by springs such as 35. The opposite face of the adaptor 13 is grooved to mount annular seals 36, and to provide an annular groove 37 in which a graphite seal (not shown) may be mounted for providing sealing in the event of fire. Various alternative forms for the seals 36 are illustrated to an enlarged scale in the margin of Fig. 2.

The subassembly is insertable into and withdrawable from the housing 1 through its open top, the subassembly being insertable into the housing 1 to a fully assembled condition therewith where the inclined annular surface

16 of each adaptor 13 is wedgingly engaged with a respective annular wedge-shaped ring 7. The ball member

17 is rotatable between an open position (as shown) where its through passage 18 is aligned with the aligned openings 3 and the openings through the adaptors 13, and a closed position where the openings are blocked by the ball member 17.

During servicing the housing 1 can be left connected in the pipeline and the subassembly withdrawn upwards. In this condition the rings 7 are easily accessible for replacement. Once the subassembly is withdrawn from the housing 1 the ball member 17 and the annular seals 23 are easily inspected since it is only necessary to withdraw outwardly the adaptors 13 and there is no need to remove the ball member 17.

The securing of the inner housing 8 within and to the outer housing 1 may be achieved in various ways. Where the open tops of both housings are flanged a quick-release manacle clamp 24 may be used.

Alternatively, the flanges may be bolted together as at 25. The stem 19 may be adapted at its top end 26 for various modes of actuation and the seals 23 may be biased towards the ball member 17 by springs and/or bypassed portions of the pressurised medium in the pipeline. It will also be noted that the subassembly can be pressure-tested while it is separate from the housing 1. Locating dowels are shown at 27.