GB2157809A

GB2157809A - Ball valve with built-in check valve

Info

Publication number: GB2157809A
Application number: GB08509722A
Authority: GB
Inventors: Caleffi Franco
Original assignee: Caleffi SpA
Current assignee: Caleffi SpA
Priority date: 1984-04-17
Filing date: 1985-04-16
Publication date: 1985-10-30
Also published as: DE8511077U1; GB8509722D0; GB2157809B; FR2562981B1; FR2562981A1; DE3513533A1

Abstract

In a ball valve comprising a valve casing 1, 2 having a chamber 3 communicating with a fluid inlet 4 and a fluid outlet 5, and in which a ball-type closing member 6 provided with an axial passage 7 for the fluid is situated in said chamber 3, a check valve 11 is seated inside the axial passage 7 of said ball-type closing member 6. In one closed position, for checking the seal and proper functioning of the check valve, the outlet 5 is connected to the outside via a cavity 29 in the ball member surface and a bore in fitting 26, and in another (Fig. 6) the check valve 11 is removable for in-line servicing after removing fitting 26. <IMAGE>

Description

SPECIFICATION Ball valve with built-in check valve This invention relates to a ball valve incorporating a non-return or check valve in the form of a single unit, and at least in preferred embodiments offers numerous advantages both from the point of view of construction and of the installation of the valves themselves.

In numerous appliances, it is necessary to fit a check valve in series with an on-off valve for the flow of fluid in order to prevent any possible back pressures or other accidental occurrences from causing a harmful backflow of the fluid which could, for example, contaminate the fluid upstream or, in any case, negatively affect the good working order of certain installations or equipment.

The use of separate valves, first and foremost, involves separate fitting operations, sufficient space, and higher production and installation costs.

Certain applications also call for a control of the seal of the check valve, once it has been fitted. This control is normally achieved by placing a control plug upstream to the check valve, between the latter and the ball valve.

This arrangement also calls for the fitting and assembling of separate components with relatively high costs, due both to the number of components used and to their installation; moreover, the use of separate valves in any case calls for a larger amount of space which is not always available.

This invention provides a valve which incorporates combination of a main valve, of the ball type and an auxiliary check valve in a single valve casing so as to considerably reduce the space required for their installation, and also to reduce both their installation costs and their manufacturing cost.

In a preferred embodiment of the invention, a main ball valve is provided combined with a check valve arranged in the axial passage of a ball-shaped closing member of the aforesaid main valve in which the check valve can be removed directly through a lateral aperture in the valve casing, which is used for controlling the seal of the check valve; in this way, it is possible to combine several functions in a single valve assembly with consequent economic advantages and a reduction in the space required.

According to this invention, a main ball valve and check valve assembly is provided, in which the check valve is arranged inside the casing of the ball valve, and in particular is seated inside the axial passage of the ballshaped closing member of the main valve itself. In this way, the installation of the ball valve not only involves the simultaneous installation of the check valve built into it, but does not require any substantial modification since the check valve, however it is made, is merely inside the closing ball; consequently, the check valve does not impede the rotation of the ball in any way, as it is totally housed inside the latter.

The check valve may be of any desired type, or suitable for the intended purpose, said valve being removably fitted, for example, simply screwed into the ball-type closing member or alternatively, into the seat ring nut, forming part of the valve casing itself, and forming a seal against an internal annular seat, or by means of a gasket held against a shoulder.

A further feature of this invention comprises a control outlet for the check valve consisting of a branched-off passage connecting the delivery side of the ball valve an auxiliary aperture, normally closed by a plug, through the check valve inside the ball member of the main valve, when the latter is in the condition in which it cuts off the fluid. With the ball valve and check valve assembly, the abovementioned advantages are achieved due to the fact that the ball valve is only partially modified and has the same overall dimensions as a conventional ball valve, whereas its ball closing member carries out additional functions, both of housing the check valve and for controlling the seal of the latter, with the valves installed.

According to a preferred embodiment, the branched-off passage connecting the outlet of the ball valve to the upstream side of the check valve, when the ball member is in the closed condition, can be advantageously made in the ball member which closes the valve, in a direction at right angles to the main axial passage for the fluid or, optionally, through a shallow recess in the ball closing member of the main valve which is situated in correspondence with a guide ring, as illustrated hereunder with reference to the figures in the accompanying drawings, in which:: Figure 1 shows an axial cross-sectional view, according to a first embodiment; Figure 2 shows a longitudinal sectional view of a further embodiment of the ball valve, in the open condition; Figure 3 shows a cross-sectional view similar to that of the previous figure, with the ball valve in the closed position and in which it controls the seal of the check valve; Figure 4 shows a view along the line 4-4 of Fig. 3 solely of the ball closing member and the relative guide ring on the outlet side; Figure 5 shows a partial cross-sectional view along the line 5-5 of Fig. 4; Figure 6 shows a cross-sectional view similar to that of Fig. 3, with the ball member rotated in the opposite direction, in the position for removal of the check valve; Figure 7 shows a partial cross-sectional view along the line 7-7 of Fig. 6, on the inlet side of the ball valve.As can be seen from said Fig. 1, the assembly comprises a main ball-type valve, made up of a valve casing 1, 2 defining an inner chamber 3 which communicates with a fluid inlet 4 and respectively, an outlet 5, axially aligned with the latter.

Inside the chamber 3 is a ball-type closing member 6 provided with a main axial passage 7 for connecting the inlet 4 to the outlet 5, in the operative position shown, and which cuts off such communication when the ball 6 assumes a second operative position at 90 with the latter; this position is achieved by rotating the ball 6 on an axis at right angles to the passage 7, by means of a control handle 8.

References 9 and 10 indicate the usual seal and guide rings for the ball 6 positioned against annular shoulders inside the chamber 3. It is clear, from the foregoing description that the structure of the ball valve, with the exception of the baIl 6 itself, is achieved in a wholly conventional manner. Unlike conventional ball valves, according to this invention, the ball member 6 of the main valve has been modified to receive an auxiliary check valve, housed inside the axial passage 7 in the ball member itself.In particular, in the example shown in Fig. 1, the check valve comprises a poppet 11 having a rear stem 1 2 sliding axially in a guide ring 13, the diameter of which is smaller than the internal diameter of the axial passage 7 in the ball 6; the guide ring 1 3 is connected, by means of arms 14, to a ring nut 1 5 tightly screwed into a screw thread 16 inside the passage 7 in the ball.

The poppet 11 of the check valve, is normally biased by a spring 1 7 situated around the guide stem 12, towards a seat or seal 1 8 which is held against an annular shoulder 1 9 in side the passage in the ball, by the ring nut 1 5 of the check valve.It is obvious that the check valve may be differently shaped or placed, without detriment to the innovatory principle consisting of housing said check valve directly inside the ball-shaped member 6 and in particular in the axial passage 7 in the ball itself; for example, the gasket 18 could be placed on the poppet itself which in this case would fit tightly against a rigid seat provided on the annular shoulder 1 9 on the ball or other equivalent part, for example, in the ring nut 2 or 1 5. The shape of the poppet or closing member 11 of the check valve may also be of any type and should preferably be of a shape which aids the flow of the fluid in the feeding direction, for example, ogival or spherical bowl-shaped, or the like, without excluding the possibility that, for certain applications the closing member 11 of the check valve may consist of a spherical body not biased by any thrust spring, since in this case, the counter-pressure of the fluid, or the weight of the closing member 11 itself, with the valve mounted vertically, is sufficient to push it shut. It is obvious that the position and the overall dimensions of the check valve, that is to say, of its closing member 11, 12, must be designed in such a way that no part of said member, in the operative conditions, can hinder the rotation of the ball 6. The figures from 2 to 7 of the accompanying drawings show a different embodiment of the ball valve designed to permit the control of the seal of the check valve and the removal of the closing member.

As can be seen from said Fig. 2, the assembly still comprises a main ball-type valve, made up of a valve casing 1, defining the inner chamber 3 which communicates with the inlet 4 and respectively, with the outlet 5. Inside the chamber 3 is the ball closing member 6 provided with the axial passage 7 for connecting the inlet 4 to the outlet 5, in the operative position shown, which cuts of such communication when the ball 6 assumes a second operative position at 90 as in the previous case. References 9 and 10 indicate the usual seal and guide rings for the ball 6, positioned against annular shoulders inside the chamber 3 in correspondence with the inlet 4 and the outlet 5.

In the example shown; the check valve still comprises a closing member 11 held on a tubular stem 20 sliding along a tubular guide member 21 supported by arms 22 screwed into the rear end of the axial passage 7 in the ball 6. The head of the closing member 11 is provided with a gasket 11' designed to form a seal against an annular seat 23 provided at the front end of the axial passage 7 in the ball 6, that is to say, at the end opposite to that in which the arms 22 supporting the check valve are screwed. A spring 24 normally biases the closing member 11 shut against the sealing seat 23 inside the ball 6.

In Fig. 2, the axial passage 7 in the ball closing member 6 of the main valve is aligned with the longitudinal axis of the chamber 3, between the fluid inlet 4 and the outlet 5; as mentioned previously, the ball-valve closing member 6 can be rotated to the closed position, by rotating it by 90' in an anticlockwise direction, moving from the position of Fig. 2 to the position of Fig. 3. In this second position, the axial passage 7 in the ball 6 is still orientated in such a way that the check valve has the sealing side of its closing member 11 facing towards a lateral aperture 25 in the valve casing 1, into which is screwed an intermediate tubular fitting 26 whose inner end penetrates into the chamber 3 to form a seal against the ball member 6, by means of an o-ring gasket 27. The fitting 26 is normally closed by means of a plug 28 which, when removed, (Fig. 3) connects the axial passage 7 in the ball closing member 6 to the outside in order to check the seal and the proper functioning of the check valve 11, 23. In this regard, the fluid outlet 5 is connected with the passage 7 in the ball 6 by means of a branched-off passage which, in this specific case, is defined by a circular cavity or recess 29 on the outer surface of the ball 6, having a width greater than the cross width of the guide ring 10; the cavity 29, in the second operative position of Fig. 3 of the ball closing member 6, comes to rest in correspondence with the guide ring 10 which is positioned on the fluid outlet side, so as to define a passage for the fluid between a point downstream to the ball valve and the inner chamber 3 of the casing 1, communicating with the passage inside the ball 6 itself. This condition is clearly shown in the cross-sectional views of Figs. 4 and 5 as well as in the cross-sectional view of Fig. 3 in which the cavity 29 is schematically indicated by dotted lines due to the fact that its real position is actually located in the removed upper half portion of the ball 6, like in the cross-section of Fig. 6.

By creating the branched-off passage through the cavity 29 which locally interrupts the seal between the ball member 6 and the guide ring 10 on the outlet side 5, it is possible to rotate the ball member 6 to a third position, opposite to that of Fig. 2, in which the seal in the direction of the fluid inlet 4 is ensured and in which it is possible to remove the closing member 11 of the check valve from the axial passage 7 of the ball member, through lateral aperture 25 in the valve casing 1, after removing the fitting 26, as is shown in the cross-section of Fig. 5. Consequently, in order to ensure the seal upstream, the guide ring 9 is made with an average diameter of less than the average diameter of the other guide ring 10 and in such a way that the cavity 29 comes to rest practically on the outer side of the guide ring 9 (Fig. 7), thereby ensuring the seal. Therefore, after having unscrewed the fitting 26, it is possible to remove the closing member 11 of the check valve due to the fact that the rear end of the passage 7 and the lateral aperture 25 in the valve casing 1 are larger in width than that of the closing member 11 which can thus be removed simply by unscrewing it by means of the arms 22. This solution is therefore advantageous in all those cases which call for a periodical control of the check valve, and its replacement if necessary, without having to disassemble or remove the entire ball valve which can therefore be left in the duct in which it was originally positioned.

Claims

1. A ball valve assembly comprising a valve casing having a chamber communicating with a fluid inlet and a fluid outlet and including a ball-shaped closing member located in the chamber, the ball-shaped closing member being provided with an axial passage for the fluid, and wherein a check valve is provided inside the axial passage of the ballshaped closing member.

2. A valve as claimed in Claim 1, wherein the check valve comprises a closing member removably disposed in the axial passage of the ball-shaped member.

3. A valve as claimed in Claim 1 or Claim 2, wherein the axial passage in the ball member comprises an internally threaded portion for a guiding ring nut for a closing member of the check valve, and an internal annular shoulder for a seal, or defining a valve seat for the closing member of the check valve.

4. A valve as claimed in any one of Claims 1 to 3, wherein the check valve has a closing member of part spherical, or ogive shape.

5. A valve as claimed in any one of the preceding claims, including a check valve control device comprising a passage which, in the closed condition of the ball-shaped closing member, connects the fluid outlet to the axial passage.

6. A valve as claimed in Claim 5, wherein the valve casing comprises a normally closed secondary fluid outlet aperture, towards which the check valve closing member may be orientated.

7. A valve as claimed in any one of the previous claims, characterised by the fact that, in correspondence with the aperture of the control outlet, a sealing member is provided for the ball closing member.

8. A valve as claimed in any one of the preceding claims, in which the ball valve comprises a casing defining a chamber communicating with a fluid inlet and respectively with a fluid outlet; a ball closing member in said chamber comprising an axial passage in which a check valve is positioned, wherein the ball-shaped closing member is supported in the chamber by means of lateral guide rings, and is adapted to rotate between a first position in which the axial passage communicates with the fluid inlet and outlet, and a second position in which the axial passage is rotated by substantially a right angle and the check valve closing member is orientated towards a normally closed lateral aperture in the valve casing, and in which the fluid outlet communicates with the axial passage in the ball closing member through a passage defined by a cavity on the outer surface of the ballshaped closing member positioned in correspondence with the aforementioned guide ring.

9. A valve as claimed in Claim 8, wherein the ball-shaped member is rotatable into a third position in which the axial passage is rotated by substantially a right angle with respect to the first position, in which the check valve closing member is orientated in the opposite direction to the lateral aperture and can be removed from the lateral aperture.

10. A valve as claimed in Claim 9, wherein the guide ring which is positioned closest to the fluid inlet, has a smaller average diameter than that of the other guide ring, and wherein the aforesaid cavity on the outer surface of the ball-shaped closing member is positioned, in a third position of the ballshaped closing member, on the outside of the first guide ring

11. A valve as claimed in any one of Claims 7 to 10, characterised by the fact that said cavity on the outer surface of the ball closing member is circular in shape.

1 2. A valve as claimed in any one of Claims 7 to 11, wherein the lateral aperture of the valve casing is closed by a removable plug screwed into an intermediate tubular fitting.

1 3. A valve as claimed in any one of the preceding claims, wherein the check valve comprises a poppet closing member having a tubular stem sliding along a tubular guide member provided with threaded arms which are screwed into the axial passage of the ball closing member.

1 4. A ball valve assembly including a check valve substantially as hereinbefore described with reference to Fig. 1 or Figs. 2 to 6 of the accompanying drawings.

1 5. A ball valve assembly with a check valve, in which the main ball valve comprises a valve casing having a chamber communicating with a fluid inlet and respectively a fluid outlet and in which a ball-shaped closing member provided with a main axial passage for the fluid is positioned in said chamber, characterised by the fact that the check valve is situated inside the axial passage of said ball-shaped closing member of the main valve.

16. A ball valve and check valve assembly as claimed in Claim 1, in which the ball valve comprises a casing defining a chamber communicating with a fluid inlet and respectively with a fluid outlet; a ball closing member in said chamber comprising an axial passage in which a check valve is positioned, the ball closing member being supported by means of lateral guide rings in order to rotate from a first position in which the axial passage comes to rest parallel with the axis of the chamber and communicates with the fluid inlet and outlet, to a second position at right angles to the aforesaid axis in which the check valve closing member is orientated towards a nor mally closed lateral aperture in the valve casing, and in which the fluid outlet communicates with the axial passage in the ball closing member through a branched-off passage, characterised by the fact that the branched-off passage is defined by a cavity on the outer surface of the bail closing member which comes to be positioned in correspondence with the aforesaid guide ring, and by the fact that the ball closing member can be made to rotate to a third position at right angles to the axis of the chamber, opposite the aforesaid second position, in which the check valve closing member is orientated in the opposite direction to the lateral aperture and can be removed from the lateral aperture itself.