Trunnion-type ball valve

Patent metadata

Field	Value
Publication number	US-10018276-B2
Application number	US-201515108685-A
Country	US
Kind code	B2
Filing date	Aug 27, 2015
Priority date	Oct 28, 2014
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A trunnion-type ball valve including a seat retainer ( 14 ) attaching a ball seat(s) to at least one side of a ball ( 12 ) having a through hole ( 12 a ) provided in a body ( 11 ). The ball is turnably provided via a stem ( 13 ), and the ball seat is attached in a protrusion-prevented and free state in an attachment groove formed in the seat retainer. An excessive pressure due to an abnormal pressure rise in a cavity upon full close or upon full open is configured to be relieved into a flow channel via a communication part provided between an inner peripheral surface of the ball seat and the attachment groove by moving the seat retainer in a direction opposite to the ball by self-tension utilizing the pressure and pushing-out the ball seat to a ball-side by the excessive pressure flowed into a rear-surface side of the ball seat in the attachment groove.

First claim

The invention claimed is:

1. A trunnion-type ball valve comprising:
a valve body;
a ball disposed in a flow channel through the valve body, the ball having a through hole;
a seat retainer disposed on one side of the ball, the seat retainer having an attachment groove formed therein;
a ball seat secured in the attachment groove, the ball seat being attached in a free and movable state relative to the attachment groove;
a protrusion preventing structure for preventing the ball seat from protruding from the attachment groove, the protrusion preventing structure having i) an engagement part provided on an inner peripheral surface of the attachment groove, and ii) a latch part provided on an outer peripheral surface of the ball seat; and
a communication part provided between an inner peripheral surface of the ball seat and the attachment groove,
wherein a seal diameter of a seal formed between the ball seat and the ball is larger than a back-surface side seal diameter of a seal formed between the back-surface side of the ball seat and the seat retainer, and
by utilizing an excessive pressure due to an abnormal pressure rise in a cavity upon full close or upon full open, the seat retainer is moved in a direction opposite to the ball by self-tension and the ball seat is pushed out to the ball side, the excessive pressure being set so as to be relieved into the flow channel via the communication part.

2. The trunnion-type ball valve according to claim 1 , wherein the engagement part is opposed to the latch part so as to be mutually latchable in an insertion direction to prevent protrusion of the ball seat from the attachment groove of the seat retainer.

3. The trunnion-type ball valve according to claim 2 , wherein a female thread part provided on the inner periphery of the attachment groove serves as the engagement part, a male thread part of the ball seat serves as the latch part and is configured to be screwed with the female thread part, and a rear end side of the male thread part and a rear end side of the female thread part are provided so as to be mutually latchable to prevent protrusion of the ball seat.

4. The trunnion-type ball valve according to claim 3 , wherein a thread ridge at an inner end of the female thread part and a thread ridge at an outer end of the male thread part are configured to be mutually latched to prevent protrusion of the ball seat.

5. The trunnion-type ball valve according to claim 3 , wherein at least one relief groove constituting the communication part is formed in the inner peripheral surface of the ball seat or in the attachment groove of the seat retainer so as to be opposed to the inner peripheral surface of the ball seat.

6. The trunnion-type ball valve according to claim 2 , wherein at least one relief groove constituting the communication part is formed in the inner peripheral surface of the ball seat or in the attachment groove of the seat retainer so as to be opposed to the inner peripheral surface of the ball seat.

7. The trunnion-type ball valve according to claim 1 , wherein at least one relief groove constituting the communication part is formed in the inner peripheral surface of the ball seat or in the attachment groove of the seat retainer so as to be opposed to the inner peripheral surface of the ball seat.

8. The trunnion-type ball valve according to claim 1 , wherein an inner-diameter dimension of a supporting-point position part A of the back-surface sealing of the ball seat is provided in a side closer to an inner diameter than a seal part of the ball seat is, the ball seat in a case of high pressure is configured to be elastically deformed so as to be opened while using the supporting-point position part A as a supporting point and sealing the seal part from an outer-diameter side toward an inner-diameter side at least in a surface-contact state.

9. The trunnion-type ball valve according to claim 8 , wherein a positional relation of the supporting-point position part A serving as the supporting-point position and a sealing part B and a sealing part C serving as the seal part is A<C<B with respect to the inner-diameter dimension.

10. The trunnion-type ball valve of claim 9 , wherein, in a case of an initial stage of assembly or a low fluid pressure, the sealing part B maintains a line-contact state, and the sealing part C is in a state not contacting a surface of the ball.

11. The trunnion-type ball valve according to claim 10 , wherein the seal part of the ball seat is formed into a spherical surface, a center of the spherical surface is disposed on a flow-channel axial core in the body as well as a center of the ball, and the inner diameter thereof is formed to be reduced relative to a spherical shape of the ball.

12. The trunnion-type ball valve according to claim 9 , wherein the seal part of the ball seat is formed into a spherical surface, a center of the spherical surface is disposed on a flow-channel axial core in the body as well as a center of the ball, and the inner diameter thereof is formed to be reduced relative to a spherical shape of the ball.

13. The trunnion-type ball valve according to claim 8 , wherein the seal part of the ball seat is formed into a spherical surface, a center of the spherical surface is disposed on a flow-channel axial core in the valve body as well as a center of the ball, and the inner diameter thereof is formed so as to be reduced relative to a spherical shape of the ball.

14. The trunnion-type ball valve according to claim 8 , wherein a predetermined clearance is provided between an inner peripheral surface of the attachment groove and a seal-surface-side outer peripheral surface of the ball seat so that the ball seat can be opened in a case of high pressure and so that excessive opening thereof can be suppressed.

15. The trunnion-type ball valve according to claim 14 , wherein a clearance is provided between an inner peripheral surface of the latch part formed on the attachment groove and an outer-peripheral-surface-side of the ball seat.

16. A trunnion-type ball valve having a seat retainer disposed to attach a ball seat to one side or both sides of a ball having a through hole provided in a body, the ball turnably provided via a stem, and the ball seat attached in a free and movable state in an attachment groove formed in the seat retainer so as to prevent the ball seat from protruding therefrom,
wherein an excessive pressure due to an abnormal pressure rise in a cavity upon full close or upon full open is configured to be relieved into a flow channel via a communication part provided between an inner peripheral surface of the ball seat and the attachment groove by moving the seat retainer in a direction opposite to the ball by self-tension utilizing the pressure and pushing-out the ball seat to a side of the ball by the excessive pressure flowed into a rear-surface side of the ball seat in the attachment groove,
wherein an inner-diameter dimension of a supporting-point position part A of the back-surface sealing of the ball seat is provided in a side closer to an inner diameter than a seal part of the ball seat is, the ball seat in a case of high pressure is configured to be elastically deformed so as to be opened while using the supporting-point position part A as a supporting point and sealing the seal part from an outer-diameter side toward an inner-diameter side at least in a surface-contact state.

Assignees

• Kitz Corp

Inventors

• Funato Masazumi
• Kazama Masahiro

Classifications

• F16K5/202

  with conical surfaces · CPC title

• F16K5/201

  with the housing or parts of the housing mechanically pressing the seal against the plug · CPC title

• F16K5/06 Primary

  with plugs having spherical surfaces; Packings therefor · CPC title

• F16K27/067

  with spherical plugs · CPC title

• F16K5/0689 Primary

  between housing and plug · CPC title