CA2078281A1

CA2078281A1 - Butterfly valve

Info

Publication number: CA2078281A1
Application number: CA002078281A
Authority: CA
Inventors: Carlos Bach Cantenys
Original assignee: Carlos Bach Cantenys; Bach S.A.
Current assignee: BACH SA
Priority date: 1992-02-14
Filing date: 1992-09-15
Publication date: 1993-08-15
Also published as: ITTO920574A0; PT8610U; DE4220455A1; JPH05240359A; BE1005640A6; NL9201099A; ITTO920574A1; FR2687444A1; IT1257258B; PT8610T

Abstract

ABSTRACT

Butterfly valve that includes a valve body; a valve element situated to turn within the valve body and move between a first position in which the element stops the flow of fluid through the valve, and a second position in which the flow of fluid through the valve is permitted, and means to avoid the movement of the valve element beyond the fully open position formed by a stop on the valve body and a stop on the valve element. each stop having two stop faces that act to place themselves respectively in contact with the other two stop faces: while the valve has a connection between valve elements, one of which goes through the other, each element is formed by a spline that can be aligned to allow the introduction of a pin and disaligned afterwards to hold the pin with the internal element within the other element, in order to hold the pin in the element to connect the two elements together, and because the valve has a valve seating that includes a metal element and an element of synthetic plastic material formed to make contact along a portion of its external surface, with the metal element having a flange that allows it to be joined to the valve body or valve disc; a convolution for greater flexibility, a seating tip intended to make contact with an hermetical seal with the valve disc or valve body and a support tip intended to support the seating on the valve body or valve disc under certain valve disc load conditions.

Description

BUTTERFLY VALVE 2 ~ 7 8 2 8 1 The present Invention refers to a connection between the parts of a butterfly valve~ It is particularly applicable, but not e~clusively so, to the connection between the valve element and the a~le of a butterfly valve~
Furthermore, the invention refers to the valve seating and a stop mechanism in the butterfly valve~
Many of the s~ud butterfly valves are designed with a connection from the a~cle to the valve element using bolts placed in holes that pass through the item and the axle. The problem related to this design is in the initial working of the disc when adapting to the seating or rising from it, causing high tensions on the bolts which wear and finally may break.
According to the present invention, a connection is offered between the elements, one of which passes through the other, and with this layout each element is formed with a spline that can be aligned to allow a cotter pin to be introduced and then disaligned to leave the pin held by the internal element within the other element, to thus fL~ the pin in the element and thus join the two elements together.
In the best e~ample of the invention, the two elements are the axle and the discshaped valve element in a butterfly valve. The a~le spline is shorter than that of ~e valve part and the same length as the pin. The pin has a part with a small height and the height of this part is equal to the depth of the spline in the a~le. The spline in the valve element is longer than in the a~cle and the sum of the depths of both splines is equal to the height of the pin. The pin has a groove that allows it to be lifted to remove it from the splines when the splines are in line, for e~ample with the aid of a screwdriver. The a~le is stepped at one end to limit the disalignment of the splines due to the movement of the a~le in the valve element and forms an end plate to hold the a~le in this position iD relation to the valve part and avoid access to the end of the a%le.
The invention also refers to a seating for a butterfly valve.
Such seatings are placed between the disc shaped valve part and the body of the valve, and many well known e~arnples already exist.
According to the present invention, a valve seating is supplied for a butterfly valve that may include any novel combination of the follo ving characteristics:
(a) the seating is metal.
(b) It projects either from the valve body or from the disc on the valve closure element.
(c) It has an external part that pr~jects radially from the disc.
(d) It has a convolution joined to the radially projecting portion.
(e) It has a seating tip joined to the convolution.
(f) ` It has a support tip connected to the sea~ing tip.
(g) The metal is Inconel 718 ~Kegistered Trademark).
(h) The seating is made of a polymer, for e~ample a fluoroplastic such as P.T.F.~..
(i) The seating includes an anchoring portion, a neck portion and projection from the seating.
G) The seating has metal and polymeric sections ne~ct to each other along the whole face.

According to the present invention~ a seating is offered for a butterfly valve that includes a metal element and an element of synthetic plastic materiaL shaped to be in contact along the length of a portion of their e~temal surface, with the metal element having a flange with which it can be joined to the body of the valve or the valve disc; a convolution for ~reater fle~cibilit~: a seating ~p intended to make contact for an hermetical closure with the disc or valve bodv and a support tip intended to serve as a stop for the seating in the valve body or valve disc under specific conditions pressure from the valve disc.
The present invention refers also to a stop mechanism for a butterfly valve.
In the said type of valve it is necessary to ensure as far as possible that the valve element is co~rectly orientated in the valve body when the latter is in the closed position~ that is, with its face at a right angle to the flow a~cis of the valve. Valves are known in which the stops are formed on the outside of the valve on the a~cle on which the valve element is mounted, but this system can give rise to a lack of precision bcause the a~le rnay be twisted between the stops and the valve element. Valves are also known in which stops are formed inside the body of the valve, corning into contact with the perimeter of the valve element when the element is in the closed position, but this system can also give rise to a lack of precision because the a~cle bends under the pressure and the element may have a tendency to pivot round the stop rather than round the a~cle~ giving rise to unequal wear in the valve seating. One aspect of the invention is intended to mitigate these problems.
According to the present invention, a butterfly valve is offered that has a valve body~ a valve element placed so as to turn within the body of the valve, to movebetween a first position in which the element stops the flow of fluid through the valve, to a second position in which the fluid is allowed to flow through the valve, and means to avoid the movement of the valve element beyond the fully open position~formed by a stop in the body of the valve and a stop on the valve element, with each stop having two stop faces that work to make contact with the other two sides of the stop respectively.
In a best example of the invention~ the means to avoid movement are formed by a stop in the body of the valve and a stop on the valve element. Each stop has two stop faces that work to make contact respectively with the two stop faces on the other stop. A pair of stop faces make contact with the valve element in the fully closed position and the other p3ir make contact with the valve element in the fully open position. The first pair of stop faces make contact at a right angle to the plane of the front face of the valve element. The other pair make contact on a 45 plane to the plane of the front face.
So that the present invention may be more clearly understood, described below is a practical version of the same as an example~ taking as a reference the a~ched drawings, in which:
Figure 1 s~.ows a side, sectional view of a partially assembled butterfly valve,according to the invention; and Figure 2 shows the valve of Figure 1 completely assembled.
Figure 3 shows a sectional view of part of a butterfly valve.
Figure 4 is a sectional view, par~ally schematic, of a butterfly valve in the closed position.
Figure S is a sectional view, partially schematic, of the butterfly valve in Figure 4, in the open position.

2~2~1 Figure 6 is a partial view in perspective of a detail of the valve in Figures 4 and 5; and Figure 7 is also a partial view in perspective of a detail of the valve.
Referring to the drawings~ the butterfly valve has a valve body 1 in which a disc shaped valve element 2 is mounted on an axle 3 in order to turn. The a~le 3passes through holes in the body 1 and element 2. The axle has a stepped portion 4 at its upper end which is placed in an additional part S of the internal diameter of the valve body. The valve element 2 and the a~le 3 in which it is introduced, are specially formed to allow mutual connection between element 2 and the a~le 3. The groove on the a~le is indicated by reference 7 and that on element 2 by reference 8.
The pin 6, oblong and of a constant thickness. has a hei~ht correspondin~ to the depth of the open groove 8 in element 2, plus the depth of groove 7 in the axle 3.
A third of the length of the pin has a lesser height at 10, corresponding to the hei8ht of the axle groove. A groove 9 for a screwdriver is forrned in the end of the pin 6, covering its whole width. The groove on pin 7 is formed to the e~cact length of the pin 6 at the exact depth of the height reduced by one third. The groove of the spline 8, forrned on the dorsal part of element 2, runs through the corresponding hole to the a~le 3. The length of the groove 8 is appro~imately a third grea~er than the length of the pin.
The valve is assembled as follows. The disc shaped part 2 is placed in the body of the valve 1. The a~le 3 is passed through the lower hole in the body 1, introducing it into the pass hole element until the spline groove of the axle 7 is visible through the groove of the spline in element 8. The pin 6 is introduced into the element 2, in the grooves in the disc and the a~le, with the ponion of the pin with reduced height 10 looking in the direction of the final mountin~ position of the a~cle.
After the pin 6 is introduced. the a~cle 3 is pushed up to its final position, drawing the pin upwards in the internal diameter of the element until the stepped portion 10 of the pin 6 makes contact with the end of the groove 8 in the disc element 2. The lower end of the axle 3 is held by a retainer on the axle 11 to avoid axial displacement of the axle 3~ and which hold the pin 6 in place. To dismount the axle 3 and element 2. the a~le retainer 11 is first removed. The a~le 3 is then pushed down until the pin 6 can no longer be seen in the spline groove 8. Ieaving the groove for the screwdriver in the lower end of the pin 6. uncovered. By placing an instrument in the groove 9, the pin can be raised and removed from the grooves in the a%le and disc element 7 and 8.The axle 3 can now b,e removed through the lower hole in the valve body.
The valve is formed by a valve body I that forms the main element of the valve 12 in which is situated a closing element in the valve, formed by the disc 2, which can rotate. A valve seating is placed in the body of the valve 1 between the body and the closing part 2, and held in place by means of a retainer on the seating 13 joined to the valve body 1 by screws 14. Between the retainer 13 and the body of the valve 1 sealing washers are placed 14a. The valve seating is of comple~c design and construction. The design is mainly a combination of a seating with a metal element 15 and a second element 16 of polymeric material. The polymeric material causes the primary hermetic sealing and the metal the secondary hermetic seal in case the primary seal fails due to e~cessive temperature, abrasion, etc.. Each element can be used independently with small modifications to the tooling of the retainer andlor the body.

~78~81 The pro~le of the metal seating can be broken down into t^our different geometric sections~ each one of which has identifiable functions: e.g. a radial flange 17, a radial arm with convolution 18~ a seating tip 19 and a support tip 20.
The functions of these parts are as follows:
Radial Flange This section is radial to the centre of the valve 12 and projects from the e~ternal diameter of the seating to the beginning of the radial convolution. It has a flat surt^ace fitting between the retainer of the seating 13 and the body l, through which pass an appropriate number of retaining screws 14, to anchor the seating 15 to the body l. The joints 14, that sit in hollows in the retainer 13 of the seating and the body l, can be attached to either side of the seating IS to avoid le~aks to the atmosphere. When installed on the valve, this radial flange also helps to hold the polymeric seating 16 and thus completes the anchoring chamber for this seating.
Radial Arm with Convolution This section begins at the beginning of the curvature immediately inside the radial flange 17 and is generally radial with a single convolution projecting in the opposite direction to the retainer for the seating 13. This simple convolution 18 carries out various critical functions:
a) It gives support and flexible energization to the polymer seating 16 whose profile coincides exactly with this surface. (The polymer will normally befluoroplastic, for e~ample P.T.F.F., that has a limited memory and resistence topermanent deformation. The metal seating, with the described profile, when made of material such as Inconei 718 can serve to support and erergize the polyment under all service conditions of nominal pressure/temperature in the valvel.
b) It mechanically holds the polymer seabng 16 in place.
c) It creates a flexing displacement point for the radial arm 17, thus increasing the reaction capacity of the seating.
Seatin~ Tip The seating tip 19 is formed on the end of a generally conve~ surface started atthe centre of the perpendicular curvature of the spherical surface of the seating on the perimeter of the closing element of the disc 2. This conve~c surface begins at the enternal end of the radial arm.
When the disc element 2 moves to the closed position~ itS seating edge wi)l thus make contact tangentally with the seating tip and the obstacle formed between the two seating surfaces will have optimum characteristics for hennetical sealing and the turn force of the valve.
Support Tip The support tip 20 is formed in the vortex of a generally convex surface, starting from a curved centre generally perpendicular to the ramp angle of the seating retainer (indicated by reference number 21) and therefore with a curvature that is the opposite of the seating tip described above. This ramp 21 on the seating retainer 13 forms an angle of approxima~elylS with a tangent drawn to the spherical surface of the disc seating 2 at its point of contact with the metal seating lS when the disc 2 is in the closed position.
It its free state, the support tip 20 is not in contact with the rasnp angle 210f the seating re~ainer, but as a growing seating load is generated by the closing of the disc 2, the support tip 20 is obliged to make contact with the ramp angle 21, thus increasing the rigidity of the seating lS and thus the closure force. The increase in ~782~1 the closure load makes the support tip rise up the ramp 21 of the seatin~ retainer~ thus maintaining the closure force.
Description of the SoR Seating The soft seating 16 is made of polymetic material and is a round ring held in a hollow 22 generally with a square section~ formed in the bod~ and held in the said hollow by the metal seating 15.
A radial surface on the polymeric seating 16 corresponds e~actly to the surface coinciding with the metal seating 15, while the other radial surface is flat corresponding on its external half with a reduced section to fonn an internal seating projection 23 achieved thanl~s to a bevelled surface.
This bevelled surface is opposite the hollow formed by the convolution on the other surface, thus forming a neck 24 that effectively divides the seating into an external anchoring part 14 and an interior closure part 23. The neck 24, with its lesser section, allows fle~ing by the seating projection under tbe influence of closure forces and/or pipeline pressure. The internal stem of the seating is conve~ withdimensions to form a blockage on the spherical perimeter of the seating of the disc 2 seating when it is in the closed position.
How it Functions a) The pressure applied to the side of the valve corresponding to the seating retainer, means that any reflex action of the disc 2 akes place in an axial direction against the seating retainer, thus tending to reduce the obstruction between the seating elements 15 and 16 and the perimeter of the seatin~ of the disc 2. Thus the desing of the seating elements 15 and 16 must be able to ~ke a~ial deflection to compensate this possible disc movement. The fluid will f~rst be found in metal seating 15 and will apply a~ial forces to the radial are with convolution 20, which will increase the closure force between the seating tip l9 and the spherical perimeter of the disc. The a~ial deflection of tbe radial arm 18 will also cause deflecti of the soft seating 16, due to the intimate contact between the two seating components. Thisdeflection of the soft seating 16 will also cause the seating projection 23 to pivot round the section of the neck 24, thus increasing the blochge with the sph~ricalsurface of t'ne disc. Therefore it can be seen that applying pressure in this direction.
both metal and soft seatings work in an energized way under pressure. Therefore an increase in pressure will cause an increase of the closure pressure in both seatings.
b) The pressure applied from the side of the valve corresponding to the body (i.e. the side of the a~le of the disc 2) will make any disc deflection take a generally axial direction, moving towards the seating retainer 13 and thus increasing the blockage between the spherical perimeter of the disc and t~e two seating elements 15 and 16. lhe pressure will also act on the primary soft seating 16 that, in this case, is held by means of the metal seating 15 t'nat energiæs it. The metal seating will give resilence and energization to the soft seating 16, allowing it to effeciently tolerate transitory temperatures and pressures. In cse of failure or destruction of the soft seahng 16, the pressure will then act directly on the metal seating 15, moving it in an direction; i.e. the radial aIm with convolution ~,vill come nearer to the retainer seating. At the same ~me the suppsrt tip 20 will rise by the rarnp angle of the retainer ~n the seating and rnaintain the closing force betwee~ the seating tip 19 and the spherical seating perimeter of the disc 21.
Referring ~o Figures 4 to 7, the butterfly valve is formed by a valve body 1, inwhich the valve element 2 is placed and able to rotate. Tbe valve element 2 is -- 6 ~ 1~ 7 8 2 3 mounted on an axle 3 which~ in turn, is mounted in the bodv of the valve. Both the valve element 2 and the valve ~dy 1 have stops 26 and 27. These stops cooperate in two different valve positions, the fully closed position (shown in Figure 4) and the fully open position (shown in Figure 5!- As can be seen, both stops have complementary faces to form contact surfaces in both positions. Thus faces 28 and 29 ~oin when the valve is closed and faces 30 and 31 when it is open.
Stop 26 is shown in more detail in Figure 6 and stop 27 is shown in greater detail in Fi~ure 7. Figure 6 shows the valve element 2 from the rear. It defines a hole 8a that projects from the upper to the lower part~ in which is lodged the axle 3 (not shown~. At one end of this valve hole. the material surrounding it is made to form two stop faces 28 and 30. The stop face 28 is at 90 from the plane of the front face of the valve element 2 and stop face 30 is 45 from the front face of valveelement 2.
Figure 7 shows the formation of the stop faces 29 and 30 in the valve body. It has a projection 32 tbat surrounds an opening 33 through which the axle 3 runs (not illustrated). The stop face 29 is pa~llel to the front face of the valve element 2 and the stop face 31 forms an angle of 45 with this front face when the valve element is in the fully open position.
With the device described aboYe, when the valve is in the closed position the valve element 2 is held firmly and its angular deflection reduced. With the valve closed and applying pressure in eitber direction, the element 2 can move lineally in relation to the flow and also maintain a uniforrn deflection inwards and outwards in the valve body 1. In this way, there is a reduction of angular deflection caused bv element 2 mounted excentrically that has areas of unequal pressure, and unequal wear on the seating is eliminated. The presence of open stops means that the valve element will not open further than the fully open position.
It is understood that the practical example above has been described solely as an example and many variations are possible without deviatin~ from the scope of the invention.

Claims

1. Butterfly valve formed by a valve body; a valve element situated to turn within the valve body and move between a first position in which the element stops the flow of fluid through the valve, and a second position in which the fluid isallowed to flow through the valve, and means to avoid movement of the valve element beyond the fully open position, formed by a stop on the body of the valve and a stop on the valve element, with each stop having two stop faces that act to place themselves in contact with the other two stop faces: while the valve has a connection between valve elements, one of which passes through the other because each element is formed by a spline that can be aligned to allow the introduction of a pins and then disaligned to hold the pin with the internal element within the other element, in order to hold the pin in the element to connect the two elements together, and because the valve has a valve seating formed by a metal element and an element of synthetic plastic material, formed to made contact along a portion of its external surface, with the metal part having a flange that allows it to be joined to the body of the valve or valve disc; a convolution for greater flexibility, a seating tip intended to make contact with an hermetic seal with the valve disc or valve body, and a support tip intended to give support to the seating of the valve body or valve disc under specific conditions of load on the valve disc.

2. Butterfly valve according to claim 1, characterized because a pair of stop faces on the body and the element respectively make contact with the valve element in the fully closed position.

3. Butterfly valve according to claims 1 or 2, characterized because a pair of stop faces on the body and the element respectively make contact with the valve in the fully open position.

4. Butterfly valve according to claim 2, characterized because the pair of stop faces finish at an right angle plane to the plane of the front face of the valve element.

5. Butterfly valve according to claim 3, characterized because the pair of stop faces that make contact in the fully open position of the valve are joined on a plane at 45° to the front face plane of the valve element.

6. Butterfly valve according to any of the claims 1 to 5, characterized because the valve element is held on an axle that runs through an opening in the valve body and the stop on the valve body is formed by a projection on the body that surrounds the opening.

7. Butterfly valve according to any of the claims 1 to 5, characterized because the valve element is held on an axle that runs through an opening in the valve element and the stop on the element includes a form on the valve element that surrounds the opening.

8. Valve according to claim 1, characterized because the spline of the said element is shorter than that on the other element.

9. Valve according to claims 1 or 8, characterized because the pin has a portion with less height and this height is equal to the depth of the spline in the said element.

10. Valve according to claim 1, characterized because the spline of the other element is longer than the said element and the sum of the depths of both splines is equal to the height of the pin.

11 Valve according to any of the claims 1, 8, 9 and 10, characterized becuase the pin has a groove so that it may be lifted, removing it from the splines when these are aligned.

12. Valve according to any of claims 1 and 8 to 11, characterized because the said element is stepped at one end to limit the nonalignment of the splines due to movement relative to the elements, and a plate is formed at the end to hold the position relative to the elements and avoid access by the said element to this end.

13. Valve according to any of claims 1 and 8 to 12, characterized because the said element is the axle and the other element is the closure element of the valve in the form of a disc for a butterfly valve.

14. Valve according to claim 1, characterized because the element of synthetic plastic material is a polymer.

15. Valve according to claim 14, characterized because the polymer is a fluoroplastic.

16. Valve according to claim 15, characterized because the fluoroplastic is polytetrafluorethylene (P.T.F.E.) .

17. Valve according to any of claims 1 and 14 to 16, characterized because the seating and support tips are adjacent to each other.

18. Valve according to any of claims 1 and 14 to 17, characterized because the element of synthetic plastic material forms a seating projection.

19. Valve according to claim 1, characterized because the synthetic plastic element is formed with a neck round which the said projection can pivot.

20. Valve according to claims 1 and 14 to 19, characterized because the flange on the metal element projects radially from the valve disc and is held between the valve body and a seating retainer.

21. Valve according to claim 20, characterized because the element of synthetic plastic material includes an anchoring part that is held between the metal seating and the valve body.