Two piece double acting valve seat assembly

Claim 2

In a valve having a valve body with a valve chamber therein, upstream and downstream flow passageways formed in said valve body and being in fluid communication with said valve chamber, a valve member mounted in the valve chamber for movement between open and closed positions to control the flow of fluid through the valve, seat recesses formed in said valve body on the upstream and downstream sides of the valve member and a seat assembly mounted within each seat recess, said seat assemblies each comprising: (a) an annularly shaped metallic outer seat member extending into an outer peripheral wall portion of said seat recess, and a metallic inner seat member mounted with an inner side portion of said outer seat member for movement in longitudinal alignment with said flow passageways and having a non-metallic face seal on an inner side thereof engagable with said valve member, (b) a peripheral seal between an outer peripheral portion of said outer seat member and an outer peripheral portion of said seat recess, (c) an inner seat member seal on an outer peripheral portion of said inner seat member sealingly engaged with said outer member, (d) said outer seat member peripheral seal having a diameter greater than the diameter of said inner seat member seal and said face seal having a diameter between that of said outer seat peripheral seal and said inner seat member seal, such that when fluid pressure in an associated flow passageway is greater than fluid pressure in said valve chamber then said outer seal member and said inner seat member will be urged toward said valve member, and in a reverse condition when fluid pressure in said valve chamber is greater than fluid pressure in said associated flow passageway then said outer seat member is urged away from said valve member and said inner seat member is urged toward said valve member, and (e) an auxiliary passageway including a first passageway portion through said valve body to said seat recess at a location adjacent an outer peripheral portion of said outer seat member and a second passageway portion through said outer seat member from said outer peripheral portion to an inner peripheral portion of said inner seat member, said auxiliary passageway in use communicating a seat sealant fluid through said first and second passageway portions to said inner peripheral portion of said inner seat member such that the seat sealant fluid can flow around the inner periphery of said inner seat member to said valve member for sealing between said valve member and both of said seat members.

Claim 3

The valve of claim 1 wherein: (a) said valve is a ball valve having a ball valve member mounted for rotation on trunnions about an axis generally perpendicular to said passageways, and (b) said ball valve further includes a compression spring means between said body and said outer seat member in each of said seat assemblies to urge said outer seat member toward said valve member to assist in establishing an initial seal between said face seal and said ball valve member.

Claim 4

The valve of claim 2, wherein: (a) said outer seat member has an annular groove in a face portion thereof with said inner seat member mounted in said groove, (b) said groove having a deep and radially relatively narrow portion connecting with a wider portion at a face portion of said outer seat member, (c) said inner seat member having a radially narrow annular portion positioned in a radially narrow portion of said groove in a nesting relation and having said inner seat member seal on said outer seat member.

Claim 5

The valve of claim 1, wherein: (a) said valve is a gate valve having a gate member mounted for movement between open and closed positions, (b) said gate valve further includes a compression spring between said valve body and said outer seat member to urge said outer seat member toward said gate valve member for assisting in establishing an initial seal between said face seal and said gate valve member.

Claim 6

The valve of claim 1, wherein, said valve body has an auxiliary fluid passageway from the exterior thereof into said valve chamber for in use connecting with an auxiliary fluid pressure source for applying external pressure to said valve chamber to raise pressure therein above fluid pressure in said flow passageway in order to urge said outer seat member away from said valve member and said inner member toward said valve member.

Claim 7

In a valve having a valve body with a valve chamber therein, upstream and downstream flow passageways formed in said valve body and being in fluid communication with said valve chamber, a valve member mounted in said valve chamber for movement between open and closed positions to control the flow of fluid through the valve, seat recesses formed in the valve body on the upstream and downstream sides of the valve member and a seat assembly mounted within each recess, each seat assembly comprising: (a) an annularly shaped metallic outer seat member positioned in an outer portion of said recess, and having an annular groove in a face portion thereof adjoining said valve member, (b) an annularly shaped metallic inner seat member movably mounted in said annular groove and having an annular non-metallic face seal extending from an inner annular face portion thereof to rest in sealing contact with said valve member, (c) a peripheral seal around an outer portion of said outer seat member resting in sealing contact with an outer peripheral portion of said recess, (d) a peripheral seal around an outer portion of said inner seat member in sealing contact with an outer peripheral portion of said groove, said inner seat member peripheral seal cooperating with said face seal, said valve member, and said outer seat member peripheral seal to provide a fluid-tight seal between said valve chamber, said valve member and an associated flow passageway, and (e) said annular groove has a stepped outer portion including a small diameter portion and a large diameter portion, and said inner seat member has a complementary stepped portion including a small diameter portion and a large diameter portion with said peripheral seal around said inner seat member being around said small diameter portion thereof; (f) said face seal and said outer seat member peripheral seat being sizes such that a differential area therebetween is greater on the side thereof exposed to fluid in said passageways than on the side thereof exposed to fluid in said valve chamber, such that when fluid pressure in an associated passageway is greater than fluid pressure in said valve chamber then said outer seat member and said inner seat member will be urged toward said valve member, (g) said face seal and said inner seat member peripheral seal are sized such that a differential area therebetween is greater on the side thereof exposed to fluid in said valve chamber than on the side thereof exposed to fluid in the associated flow passageway such that when fluid pressure in said valve chamber is greater than fluid pressure in said associated flow passageway then said outer seat member is urged into an outer portion of the associated recess and said inner seat member is urged toward said valve member.

Claim 8

In a valve having a valve body with a valve chamber therein, upstream and downstream flow passageways formed in said valve body and being in fluid communication with said valve chamber, a valve member mounted in said valve chamber for movement between open and closed positions to control the flow of fluid through the valve, seat recesses formed in the valve body on the upstream and downstream sides of the valve member and a seat assembly mounted within each recess, each seat assembly comprising: (a) an annularly shaped metallic outer seat member positioned in an outer portion of said recess, and having an annular groove in a face portion thereof adjoining said valve member, (b) an annularly shaped metallic inner seat member movably mounted in said annular groove and having an annular non-metallic face seal extending from an inner annular face portion thereof to rest in sealing contact with said valve member, (c) a peripheral seal around an outer portion of said outer seat member resting in sealing contact with an outer peripheral portion of said recess, (d) a peripheral seal around an outer portion of said inner seat member in sealing contact with an outer peripheral portion of said groove, said inner seat member peripheral seal cooperating with said face seal, said valve member, and said outer seat member peripheral seal to provide a fluid-tight seal between said valve chamber, said valve member and an associated flow passageway, and (e) said annular groove has a stepped outer portion including a small diameter portion and a large diameter portion, and said inner seat member has a complementary stepped portion including a small diameter portion and a large diameter portion with said peripheral seal around said inner seat member being around said small diameter portion thereof; (f) said face seal and said outer seat member peripheral seat being sizes such that a differential area therebetween is greater on the side thereof exposed to fluid in said passageways than on the side thereof exposed to fluid in said valve chamber, such that when fluid pressure in an associated passageway is greater than fluid pressure in said valve chamber then said outer seat member and said inner seat member will be urged toward said valve member, (g) said face seal and said inner seat member peripheral seal are sized such that a differential area therebetween is greater on the side thereof exposed to fluid in said valve chamber than on the side thereof exposed to fluid in the associated flow passageway such that when fluid pressure in said valve chamber is greater than fluid pressure in said associated flow passageway then said outer seat member is urged into an outer portion of the associated recess and said inner seat member is urged toward said valve member.

Claim 9

The valve of claim 6 wherein: (a) said valve is a ball valve having a ball valve member mounted for rotation on trunnions about an axis generally perpendicular to said passageways, (b) said ball valve further includes a compression spring means between said body and said outer seat member in each of said seat assemblies to urge said outer seat member toward said valve member to assist in establishing an initial seal between said face seal and said ball valve member, (c) said outer seat member has an annular groove in a face portion thereof with said inner seat member mounted in said groove, (d) said groove having a deep and radially relatively narrow portion connecting with a wider portion at a face portion of said outer seat member, and (e) said inner seat member having a radially narrow annular portion positioned in a radially narrow portion of said groove in a nesting relation and having said inner seat member seal on said outer seat member.