TOP ENTRY TRUNNION BALL VALVE SUITABLE FOR SAFE IN-LINE MAINTENANCE AND METHOD TO FACILITATE SUCH MAINTENANCE

• US 20170299070A1
• Filed: 05/25/2016
• Published: 10/19/2017
• Est. Priority Date: 04/16/2016
• Status: Active Grant

• Current Assignee: Rmebs Controls Private Limited
• Original Assignee: Amit Shah
• Inventors: SHAH, AMIT, KOTHADIA, AJIT
• Granted Patent: US 9,835,259 B2
• Time in Patent Office: Days
• CPC Class Codes: F16K 27/067 with spherical plugs
• CPC Class Codes: F16K 5/0636 the spherical plug being insertable from the top of the housing
• CPC Class Codes: F16K 5/0663 Packings
• CPC Class Codes: F16K 5/201 with the housing or parts of the housing mechanically pressing the seal against the plug
• CPC Class Codes: Y10T 137/0508 Ball valve or rotary ball valve

Abstract

A top entry trunnion mounted rotary ball valve suitable for safe in-line maintenance, comprising a main valve body having an upstream and a downstream ball seat assembly, the ball seat assemblies further comprising a soft insert seal, a ball seat, a seat retainer and a plurality of compression springs in between the ball seat and the seat retainer. A guiding groove on the cylindrical surface of each of the ball seats, having a first end and a second end at an axial distance equal to or more than the measure of retraction required so as to get the mechanical clearance adequate to remove or assemble the ball member, the angular span between the first end and the second end of the guiding groove can be less than 180 degrees or more than 360 degrees, depending on the overall size of rotary ball valve, in order to be able to manually retract in the ball seats. Each ball seat is retracted in the recess, with the aid of a guide assembly, by using a straight rod, against a force Fc of the compression springs and the mechanical clearance is created between the ball member and the soft insert seal, to remove or assemble the ball member and or any or all components from or inside the valve body. An angle of grove a, which is an angle between the flange and the guide groove, is kept of relatively of low value for big sized valves whence an angular span of guiding groove becomes relatively higher so that the required axial distance, which is equal to or more than the measure of retraction required so as to get the mechanical clearance adequate to remove the ball member, is attainable between the first end of the groove and the second end of the groove, by a Force Ft apply-able by a person of normal physique, and vice versa for a small sized valve. The rotary ball valve cannot be put in operation inadvertently if the ball seats are in retractable or retracted position.

Claims

1. A top entry trunnion mounted rotary ball valve for safe in-line maintenance, comprising:

a. a main valve body having end connections;

b. a valve top cover connected to the main valve body by a plurality of studs;

c. an inlet flow passage and an outlet flow passage;

d. a stepped upstream recess for accommodating an upstream ball seat assembly in the inlet flow passage, and a stepped downstream recess for accommodating a downstream ball seat assembly in the outlet flow passage;

e. a ball member having a central bore;

f. the upstream ball seat assembly and the downstream ball seat assembly further comprises a soft insert seal, a ball seat, a seat retainer and a plurality of compression springs in between the ball seat and the seat retainer, the seat retainer disposed rigidly in the stepped upstream recess in the main valve body, the seat retainer having a plurality of spring locators in the form of cavities or projections wherein or whereon the plurality of compression springs is provided;

g. a plurality of seal grooves and a sealant groove on a cylindrical surface, a tubular cavity for disposing the soft insert seal, on each of the ball seat;

h. a guiding groove on the cylindrical surface of each of the ball seats, the guiding groove having a groove depth and a groove width, a first end of the guiding groove in a vicinity of a flange on a ball end of the ball seat, while a second end of the guiding groove at an axial distance equal to or more than a measure of retraction required so as to get a mechanical clearance, adequate to remove the ball member, the second end of the guiding groove having a diverging width construction which eases an engagement of a guide assembly, an angular span between the first end and the second end of the guiding groove can be less than 180 degrees or more than 360 degrees, depending on the overall size of the rotary ball valve, in order to be able to manually retract-in or retract-out the ball seats;

i. a plurality of engaging holes on an outer periphery of the flange on each of the ball seat, the engaging holes are equally spaced from one another, a radial axis of each engaging hole orthogonal to the flange of the ball seat, the engaging holes are on the entire outer periphery of the flange or only on part of the outer periphery depending on the size of the rotary ball valve;

j. a threaded through-hole, on each of an upper surface of an inner wall of the main valve body, on the other side of which is provided the stepped upstream recess for accommodating the upstream ball seat assembly, also the stepped downstream recess for accommodating the downstream ball seat assembly, the threaded through-hole is such located that a head of a compatible screw when engaged in the threaded through-hole is easily and clearly accessible from top of the ball valve after dismantling the valve top cover;

k. at least two guide assemblies, each guide assembly having a guide screw and a freely rotating bearing fitted at a far end of the guide screw, an overall diameter of the freely rotating bearing less than a shank diameter of the guide screw, a guide height of the guide assembly being such that when the guide assembly is tightened in the threaded through-hole, a bearing face of the freely rotating bearing does not touch a groove surface on the guiding groove of the ball seat;

the seat balls are retracted in the recess, by using a straight rod of a cross sectional dimension slightly less than a cross sectional dimension of the plurality of engaging holes, against a force Fc of the compression springs and the mechanical clearance is created between the ball member and the soft insert seal, to remove or assemble the ball member, the ball seats are retracted out either to bring the ball seats in a sealing position or for removing the ball seats and or any component from inside the main valve body, an angle of groove α

, which is the angle between the flange and the guiding groove, has an inverse relationship with the angular span of the guiding groove so that the required axial distance, which is equal to or more than the measure of retraction required so as to get the mechanical clearance adequate to remove the ball member, is attainable with an optimum force Ft, the angle of groove α

being of relatively low value for big sized valves whence the angular span of the guiding groove becomes relatively higher so that the required axial distance is attainable between the first end of the groove and the second end of the groove, by applying a force Ft.

2. The top entry trunnion mounted rotary ball valve for safe in-line maintenance as claimed in claim 1, wherein the guide assembly having the head has mechanical interference with an inside of the valve top cover, disabling the possibility to fix the valve top cover while the guide assembly is still engaged with the threaded through-hole in the main valve body.

3. The top entry trunnion mounted rotary ball valve for safe in-line maintenance as claimed in claim 1, wherein each of the guide assembly is securely assembled in a parking hole provided on an inside of the valve main body under normal functioning of the rotary ball valve.

4. The top entry trunnion mounted rotary ball valve for safe in-line maintenance as claimed in claim 1, wherein each of the guide assembly is securely assembled in the parking hole provided on the inside of the valve top cover under normal functioning of the rotary ball valve.

5. The top entry trunnion mounted rotary ball valve for safe in-line maintenance as claimed in claim 1, wherein the parking hole has a depth higher than the guide height of the guide assembly, so that the bearing face of the freely rotating bearing fitted at the far end of the guide assembly is not damaged while the guide assembly is engaged in the parking hole.

6. The top entry trunnion mounted rotary ball valve for safe in-line maintenance as claimed in claim 1, wherein the engaging holes are circular in shape.

7. The top entry trunnion mounted rotary ball valve for safe in-line maintenance as claimed in claim 1, wherein the engaging holes are of a specific shape.

8. The top entry trunnion mounted rotary ball valve for safe in-line maintenance as claimed in claim 1, wherein the straight rod is either a circular rod or a rod of specific profile.

9. A method to facilitate an on-line maintenance on a top entry trunnion mounted rotary ball valve, the rotary ball valve comprising a main valve body having two threaded through-holes, a valve top cover connected to the main valve body by a plurality of studs, the valve top cover and or the main valve body having two parking holes, a ball member, an upstream ball seat assembly and a downstream ball seat assembly further comprising a soft insert seal, a ball seat, a seat retainer and a plurality of compression springs in between the ball seat and the seat retainer, a plurality of engaging holes on a flange on each of the ball seat, a guide assembly on each of the ball seat, the method to facilitate such maintenance comprising the steps of:

a. removing the valve top cover by opening the plurality of studs;

b. disengaging each of the two guide assemblies from respective parking holes;

c. engaging and tightening each of the two guide assemblies in the respective threaded through-hole;

d. engaging a straight rod in an accessible engaging holes of the flange of either ball seat and turning the straight rod in the marked direction by a tangential force Ft till another engaging hole becomes accessible;

e. engaging the straight rod in newly accessible hole and repeating the step till a first end of the guiding groove reaches the guide assembly and or a mechanical clearance between the soft insert seal and a sealing surface of the ball member is attained by retracting-in of the ball seat against a force Fc of the compression springs;

f. engaging the straight rod in an accessible engaging hole of the flange of the other ball sea and turning the straight rod in the marked direction by the tangential force Ft till another engaging hole becomes accessible;

g. engaging the straight rod in newly accessible hole and repeating the step till a first end of the guiding groove reaches the guide assembly and or the mechanical clearance between the soft insert seal and a sealing surface of the ball member is attained by retracting-in of the ball seat against the force Fc of the compression springs;

h. removing or assembling the ball member from the main valve body;

i. engaging the straight rod in an accessible engaging hole of the flange of either ball seat and turning the straight rod in the reverse direction by the tangential force Ft till another engaging hole becomes accessible;

j. engaging the straight rod in newly accessible hole and repeating the step till a second end of the guiding groove reaches the guide assembly, by retracting-out the ball seat;

k. engaging the straight rod in an accessible engaging hole of the flange of the other ball seat accessible and turning the straight rod in the reverse direction by the tangential force Ft till another engaging hole becomes accessible; and

l. engaging the straight rod in newly accessible hole and repeating the step till the second end of the guiding groove reaches the guide assembly, by retracting-out the ball seat.

10. A method to facilitate an on-line maintenance on a top entry trunnion mounted rotary ball valve, the rotary ball valve comprising a main valve body having two threaded through-holes, a valve top cover connected to the main valve body by a plurality of studs, the valve top cover and or the main valve body having two parking holes, a ball member, an upstream ball seat assembly and a downstream ball seat assembly further comprising a soft insert seal, a ball seat, a seat retainer and a plurality of compression springs in between the ball seat and the seat retainer, a plurality of engaging holes on a flange on each of the ball seat, a guide assembly on each of the ball seat, the method to facilitate such maintenance comprising the steps of:

a. removing a valve top cover by opening the plurality of studs;

b. disengaging each of the two guide assemblies from respective parking holes;

c. engaging and tightening each of the two guide assemblies in the respective threaded through-holes;

d. engaging a straight rod in an accessible engaging hole of the flange of each of the ball seat and turning both the straight rods in the respective marked direction by a tangential force Ft till another engaging holes becomes accessible;

e. engaging the straight rods in newly accessible holes and repeating the step till a first end of the guiding groove of each ball seat reaches the guide assembly and or a mechanical clearance between the soft insert seal and a sealing surface of the ball member is attained by retracting-in of the ball seats against a force Fc of the compression springs;

f. removing or assembling the ball member from the main valve body,

g. engaging the straight rod in an accessible engaging hole of the flange of each of the ball seat and turning both the straight rods in a reverse direction till another engaging holes becomes accessible; and

h. engaging the straight rods in newly accessible holes and repeating the step till a second end of the guiding grooves of each ball seat reaches the guide assembly, by retracting-out the ball seats.

11. The method to facilitate the on-line maintenance on the top entry trunnion ball valve as claimed in claim 9 or 10, wherein the retracting-out the ball seats brings back the ball seats in a sealing position.

12. The method to facilitate the on-line maintenance on the top entry trunnion ball valve as claimed in claim 9 or 10, wherein the retracting-out the ball seats enables removing the ball seats and or any component from inside the main valve body.