GB2238094A

GB2238094A - Ball valve, connector hub and seal

Info

Publication number: GB2238094A
Application number: GB9023681A
Authority: GB
Inventors: Michael J Green; Edward Joseph Barrette; Harold T Pentesco
Original assignee: HAVLIK TECHNOLOGIES Inc
Current assignee: HAVLIK TECHNOLOGIES Inc
Priority date: 1989-10-31
Filing date: 1990-10-31
Publication date: 1991-05-22
Also published as: GB8924470D0; GB9023681D0; CA2028754A1

Abstract

A ball valve is disclosed having the characteristics of good sealing integrity throughout the thermal and mechanical stress of high pressure liquid flow. The valve main body (12) has a ball (16) with ring seat (18) and rotating stem (24) mounted therein and defining a linear control passage (14) therethrough. An integral hub (32) with proboscis member (34) and cooperating linear passage (38) is mounted in sealed interface on one side of main body (12) with a clamping device (36) circumferentially securing hub (32) and main body (12) together. Member (34) is sealed in body (12) by sealing means (44) cooperating with shoulder (40) and ledge (42). <IMAGE>

Description

HIGH PERFORMANCE VALVE This invention relates to ball valves for relatively high pressure liquid flow. More particularly, it relates to ball valves having improved sealing integrity throughout the thermal and mechanical stress loads exhibited by such valves during high pressure liquid flow.

Conventional high performance ball valves utilize a flanged body connection which is held together by means of studs and nuts secured parallel to the flow direction. Such designs fail to demonstrate satisfactory performance during high thermal and mechanical load. Furthermore, the integrity of the packaging seal is often unsatisfactory due o the unequal distribution of force against the packing itself.

In United States Patent 3,977,707 of Oliver issued August 31, 1978, a ball valve is described having a pair of pivotable tubular members which permit the inlet and out ends of the valve to be pivoted in angular relationship to each other. This valve was found to be particularly suitable for drilling operations where it is necessary to avoid undue stress on the valve joint from the riser pipe. While ball valves of this type may be useful for the particular drilling operations described in this reference, such valve would not be suitable for operation under the high pressure fluid flow utility described in this application.

British Patent 1,066,089 published April 19, 1987 discloses a sealing ring for engaging the flared surfaces of annular parts of a valve. The flared surfaces as sealed together by securing a unique elastic steel sealing ring between the flanged ends of the valve parts and this is held together by a conventional sealing clamp. This reference does not allow for the insertion of an integral hub connected at one end of the main body and held in tight sealing alignment by means of circumferentially secured clamps. The clamping means disclosed in the British reference would not be capable of withstanding the high fluid pressures of ball valve of the present application.

The present invention utilizes a unique combination of a clamp type connector, together with an integral (i.e. one piece) hub and cylindrical proboscis which axially penetrates the body bore. The subject proboscis has a predetermined and finitely calculated dimensional interface with the internal bore diameter of the main body segment, such that when radial stress loads are generated from service conditions, (i.e.

thermal and mechanical cyclic loads), the resultant forces make initial surface contact with the thick wall (i.e. major mass) portion of the body, as opposed to the centre of the studded flanged connection, as in the case of the conventional high performance ball valve.

The ball valve of this invention is characterized in having a main body with an axial passage therethrough; a ball and ring seat mounting positioned within said main body, with a cooperating central opening therethrough and a valve stem mounted perpendicular to said axial passage for engaging said ball and rotating said central opening relative to said axial passage; an integral hub including a proboscis member secured at one end of said main body with a central passage therethrough defining a portion of said axial passage; a shoulder portion defining a portion of said axial passage; a shoulder portion on said proboscis interfacing with a cooperating ledge on said main body and a seal means between said shoulder and ledge for maintaining the sealing integrity of the valve during passage of high pressure fluid therethrough; said seal means being spaced from said valve stem and ball and seat mounting, and a clamping means for circumferentially securing said body member and hub member.

In the Drawings: Figure 1 is a partial cross-sectional side view of the ball valve with a portion of the clamping means shown in broken illustration; Figure 2 is a cross-sectional view of a portion of the valve of Figure 1; and Figure 3 is a cross-sectional longitudinal view of the valve stem, packing gland and retaining means.

In Figure 1, a ball valve 10 is shown in cross-section, having a main body 12 with an axial passage 14 therethrough.

The valve includes a centrally positioned ball 16 fitted within a ring seat mounting 18. The ball and mounting have a central opening 20 which is coextensive with passage 14. A ring gasket 22, which is positioned within a recess between seat mounting 18 and the main body 12 prevents fluid leakage from passage 14.

A valve stem 24 is mounted in main body 12 perpendicular to the direction of passage 14 within a transverse passage 25 in said body, and is mechanically connected at its lower end to ball 16 so that by rotating stem 24 about its axis, ball 16 fluid flow through opening 20 is disrupted. Stem 24 includes a shoulder portion 26 adjacent main body ledge 28 with a sealing ring 30 therebetween for inhibiting leakage through passage 25.

Stem 24 is sealed at its upper end by means of a packing glad 50 which will be described below.

An integral hub 32 including a proboscis member 34 is joined at one end to main body 12 and secured by means of a clamping device 36 around the entire joint, thereby providing reinforcement during high pressure operations. Proboscis member 34 has a central passage 38 therethrough which is integral with axial passage 14. Proboscis 34 has a shoulder portion 40 which interfaces with a cooperating ledge 42 on the main body and has a sealing means 44 for inhibiting leakage in the area between hub 32 and main body 12.

In the embodiment shown in Figure 1, the lower end of transverse passage 25 is closed off by means of a closure nut 46 and packing 48 in a manner well known in the art.

The integrity of the sealing means of the present valve is precalculated on the basis of certain dimensions which are illustrated in Figure 2, in accordance with the following W1 the following formulae; A MIN. = A MIN. = B MIN. = C MIN. =

WHEN WHEN

A = Distance from centerline of stem bore to body seat shoulder B = Distance from body seat contact surface to the code pressure containment diameter C = Distance from the body hub face to the body seal contact surface

= Stem bore maximum wetted diameter = Code pressure containment thickness for the stem bore maximum wetted diameter = Bottom body access maximum wetted diameter #= Code pressure containment thickness for the bottom body access maximum wetted diameter

= Body seal contact diameter = Body bore code wall thickness F = Distance from hub face to back side of hub

= Hub clamp clearance distance = Angle between body minor and major diameter on the clamp side of the body.

The upper end of transverse passage 25 is closed off by stem packing gland 50 which is illustrated in end view in Figure 3. A stem hub 52 is centered around stem 24 and positioned in a recess within body 12 for securing valve packing 54 therebetween. A retaining plate 56 is positioned on stem 24 and sits on hub seat 58. A pair of retaining bolts 60a and 60b are fixed at their lower end to body 12 and includes tightening nuts 62a and 62b and corresponding pairs of opposed, concavo-convex resilient lock washers 64a and 64b. As the nuts and washers are tightened into position, plate 56 is forced down on hub seat 58 to provide a downward force on valve packing 54. Should one of the nuts be tightened unevenly with respect to the other, the resilient lock washers compensate, to provide equal downward force against retaining plate 56 and thereby serves to avoid unevenness of downward pressure against the packing that should result in fluid leakage through the weaker stress point.

It can be noted that in this invention, any diameter of hub proboscis or any desired surface contact pressure can be provided for, thereby eliminating the necessity of trial and error in providing effective body connection sealing under significant radial and axial loads. In this respect, the disclosed valve exhibits maximum versatility in service conditions.

Claims

CLAIMS:

1. A ball valve characterized in having a main body with an axial passage therethrough; a ball and ring seat mounting positioned within said main body with a cooperating central opening therethrough and a valve stem mounted perpendicular to said axial passage for engaging said ball and rotating said central opening relative to said axial passage; an integral hub including a proboscis member secured at one end of said main body with a central passage therethrough defining a portion of said axial passage, a shoulder portion on said proboscis interfacing with a cooperating ledge on said main body and a seal means between said should and ledge for maintaining the sealing integrity of the valve during passage of high pressure fluid therethrough; said seal means being spaced from said valve stem and ball and seat mounting; and, a clamping means for circumfernetially securing said body member and hub member.

2. A ball valve as claim in claim 1 which further comprises a packing gland including a stem hub between the valve stem and main body for securing a valve packing therebetween, and a retaining plate around said stem and positioned on said stem hub, said plate being secured to said main body by a pair of bolts on opposite side of said stem and perpendicular thereto for directing a downward axial force on said stem hub.

3. A ball valve as claimed in claim 2 wherein each of said bolts includes a resilient locking means for equalizing the downward securing force on said plate.

4. A ball valve substantially as described with particular reference to the drawings.