Check valve assembly

Claim 2

A check valve assembly comprising: outer annular housing means having first and second aperture means through the wall thereof and having an irregular bore therethrough; sliding annular mandrel means having an irregular exterior surface having annular shoulder means thereon disposed between the first and second aperture means through said outer annular housing means, said sliding annular mandrel means being slidably disposed in a first position within the bore of said outer annular housing means in sealing engagement therewith having the annular shoulder means of said sliding annular mandrel means communicating with the first aperture means of said outer annular housing means while the bore of said sliding annular mandrel means communicates with the second aperture means of said outer annular housing means; check valve seal means retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, said check valve seal means allowing communication from the bore of said outer annular housing means to the exterior thereof but preventing communication from the exterior of said outer annular housing means to the bore thereof; and shear means disposed within said outer annular housing means having a first portion thereof engaging a portion of the irregular exterior surface of said sliding annular mandrel means and having a second portion thereof engaging a portion of the irregular bore through said outer annular housing means, said shear means initially preventing movement of said sliding annular mandrel means with respect to said outer annular housing means when said sliding annular mandrel means is disposed within said outer annular housing means in a first position therein until a predetermined amount of force is applied to said annular sliding mandrel means.

Claim 3

The check valve assembly of claim 1 further comprising: locking dog means disposed within said outer annular housing means, said locking dog means allowing movement of said sliding annular mandrel means from the first position within said outer annular housing means.

Claim 4

The check valve assembly of claim 2 further comprising: locking dog cavity means disposed on said sliding annular mandrel means, said locking dog cavity means being disposed on said sliding annular mandrel means to allow movement of said sliding annular mandrel means from the first position within said annular housing means to a second position within said annular mandrel means, whereby said locking dog means engage said locking dog cavity means to prevent movement of said sliding annular mandrel means from the second position within said sliding annular housing means.

Claim 5

The check valve assembly of claim 3 further comprising: lug means on the exterior surface of one end of said sliding annular mandrel means; and longitudinal cavity means located in a portion of the irregular bore of said outer annular housing means slidably receiving said lug means of said sliding annular mandrel means therein.

Claim 6

The check valve assembly of claim 1 wherein said outer annular housing means comprises: annular adapter means having the second aperture means through the wall thereof and an irregular bore therethrough; annular shear case means having one end thereof secured to one end of the annular adapter means, the annular shear case means having an irregular bore therethrough; annular pressure housing means having one end thereof secured to the other end of the annular shear case means, having the first aperture means through the wall thereof and having an irregular bore therethrough, the annular pressure housing means receiving the annular shoulder means of said sliding annular mandrel means therein; and annular nipple means having one end secured to the other end of the annular pressure housing means, having an irregular bore therethrough and having longitudinal cavity means located in a portion of the irregular bore.

Claim 7

The check valve assembly of claim 5 wherein said sliding mandrel means comprises: annular sealing mandrel means having an irregular exterior surface thereon; and shear mandrel means secured to one end of the annular sealing mandrel means, the shear mandrel means having an irregular exterior surface thereon, having shear means abutment means on the end of the annular shear mandrel means secured to the annular sealing mandrel means, having annular shoulder means on the irregular exterior surface thereof and having lug means on the other end of the shear mandrel means, the lug means slidably engaging the longitudinal cavity means located in a portion of the irregular bore of the annular nipple means of said outer annular housing means.

Claim 8

The check valve assembly of claim 6 further comprising: locking dog means disposed within a portion of the irregular bore of the shear case means of said outer annular housing means and slidably engaging the end portion of the shear mandrel means secured to one end of the sealing mandrel means; and locking dog cavity means located in the irregular exterior surface of the shear mandrel means aft of the end of the shear mandrel means secured to the one end of the sealing mandrel means whereby when said sliding annular mandrel means moves from the first position in said outer annular housing means, which allows communication through said second apertures from the bore of said outer annular housing means to the exterior thereof, to a second position within said outer annular housing where communication through the second apertures from the bore of said outer annular housing means to the exterior thereof is prevented by said sliding annular mandrel means, the locking dog means engage the locking dog cavity means to prevent movement of said sliding annular mandrel means from the second position within the outer annular housing means.

Claim 9

The check valve assembly of claim 7 wherein said shear means comprise: first shear sleeve means having a plurality of apertures therein engaging a portion of the irregular exterior surface of said sliding annular mandrel means; second shear sleeve means having a plurality of apertures therein substantially aligned with the plurality of apertures in the first shear sleeve means engaging a portion of the irregular bore through said outer annular housing means; and shear pin means installed in the plurality of apertures in the first and second shear sleeve means, thereby preventing relative movement of the first shear sleeve means with respect to the second shear sleeve means until a predetermined amount of force is applied to said annular sliding mandrel means, the force being transferred from the portion of the irregular exterior surface of said sliding annular mandrel means to the first shear sleeve means causing the shear pin means to be sheared, thereby allowing relative movement between the first shear sleeve means and the second shear sleeve means.

Claim 10

The check valve assembly of claim 1 wherein said check valve seal means comprises: an elastomeric skirt retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, the elastomeric skirt being radially expansible outwardly.

Claim 11

The check valve assembly of claim 1 wherein said sliding annular mandrel means comprises a pressure balanced sliding annular mandrel means.

Claim 12

A check valve assembly comprising: outer annular housing means having first and second aperture means through the wall thereof and having an irregular bore therethrough, said outer annular housing means comprising: annular adapter means having the second aperture means through the wall thereof and an irregular bore therethrough; annular shear case means having one end thereof secured to one end of the annular adapter means and having an irregular bore therethrough; annular pressure housing means having one end thereof secured to the other end of the annular shear case means, having the first aperture means through the wall thereof and having an irregular bore therethrough; and annular nipple means having one end secured to the other end of the annular pressure housing means, having an irregular bore therethrough and having longitudinal cavity means located in a portion of the irregular bore; sliding annular mandrel means having an irregular exterior surface having annular shoulder means thereon disposed between the first and second aperture means through said outer annular housing means, said sliding annular mandrel means being slidably disposed in a first position within the bore of said outer annular housing means in sealing engagement therewith having the annular shoulder means of said sliding annular mandrel means communicating with the first aperture means of said outer annular housing means while the bore of said sliding annular mandrel means communicates with the second aperture means of said outer annular housing means, said sliding annular mandrel means comprising: annular sealing mandrel means having an irregular exterior surface thereon; and shear mandrel means secured to one end of the annular sealing mandrel means, the shear mandrel means having an irregular exterior surface thereon, having shear means abutment means on the end of the annular shear mandrel means secured to the annular sealing mandrel means, having annular shoulder means on the irregular exterior surface thereof and having lug means on the other end of the shear mandrel means, the lug means slidably engaging the longitudinal cavity means located in a portion of the irregular bore of the annular nipple means of said outer annular housing means; check valve seal means retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, said check valve seal means allowing communication from the bore of said outer annular housing means to the exterior thereof but preventing communication from the exterior of said outer annular housing means to the bore thereof, said check valve seal means comprising: an elastomeric skirt retained on the exterior of said outer annular housing means blocking the second aperture means to said outer annular housing means, the elastomeric skirt being radially expansible outwardly; and shear means disposed within said outer annular housing means having a first portion thereof engaging a portion of the irregular exterior surface of said sliding annular mandrel means and having a second portion thereof engaging a portion of the irregular bore through said outer annular housing means, said shear means initially preventing movement of said sliding annular mandrel means with respect to said outer annular housing means when said sliding annular mandrel means is disposed within said outer annular housing means in a first position therein until a predetermined amount of force is applied to said annular sliding mandrel means, said shear means comprising: first shear sleeve means having a plurality of apertures therein and engaging a portion of the irregular exterior surface of said sliding annular mandrel means; second shear sleeve means having a plurality of apertures therein substantially aligned with the plurality of apertures in the first shear sleeve means and engaging a portion of the irregular bore through said outer annular housing means; and shear pin means installed in the plurality of apertures in the first and second shear sleeve means, thereby preventing relative movement of the first shear sleeve means with respect to the second shear sleeve means until a predetermined amount of force is applied to said annular sliding mandrel means, the force being transferred from the portion of the irregular exterior surface of said sliding annular mandrel means to the first shear sleeve means causing the shear pin means to be sheared, thereby allowing relative movement between the first shear sleeve means and the second shear sleeve means.

Claim 13

A check valve assembly comprising: outer annular housing means having first and second aperture means through the wall thereof and having an irregular bore therethrough, said outer annular housing means comprising: annular adapter means having the second aperture means through the wall thereof and an irregular bore therethrough; annular shear case means having one end thereof secured to one end of the annular adapter means and having an irregular bore therethrough; annular pressure housing means having one end thereof secured to the other end of the annular shear case means, having the first aperture means through the wall thereof and having an irregular bore therethrough; and annular nipple means having one end secured to the other end of the annular pressure housing means, having an irregular bore therethrough and having longitudinal cavity means located in a portion of the irregular bore; sliding annular mandrel means having an irregular exterior surface having annular shoulder means thereon disposed between the first and second aperture means through said outer annular housing means, said sliding annular mandrel means being slidably disposed in a first position within the bore of said outer annular housing means in sealing engagement therewith having the annular shoulder means of said sliding annular mandrel means communicating with the first aperture means of said outer annular housing means while the bore of said sliding annular mandrel means communicates with the second aperture means of said outer annular housing means, said sliding annular mandrel means comprising: annular sealing mandrel means having an irregular exterior surface thereon; and shear mandrel means secured to one end of the annular sealing mandrel means, the shear mandrel means having an irregular exterior surface thereon, having shear means abutment means on the end of the annular shear mandrel means secured to the annular sealing mandrel means, having annular shoulder means on the irregular exterior surface thereof and having lug means on the other end of the shear mandrel means, the lug means slidably engaging the longitudinal cavity means located in a portion of the irregular bore of the annular nipple means of said outer annular housing means; check valve seal means retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, said check valve seal means allowing communication from the bore of said outer annular housing means to the exterior thereof but preventing communication from the exterior of said outer annular housing means to the bore thereof, said check valve seal means comprising: an elastomeric skirt retained on the exterior of said outer annular housing means blocking the second aperture means to said outer annular housing means, the elastomeric skirt being radially expansible outwardly; and shear means disposed within said outer annular housing means having a first portion thereof engaging a portion of the irregular exterior surface of said sliding annular mandrel means and having a second portion thereof engaging a portion of the irregular bore through said outer annular housing means, said shear means initially preventing movement of said sliding annular mandrel means with respect to said outer annular housing means when said sliding annular mandrel means is disposed within said outer annular housing means in a first position therein until a predetermined amount of force is applied to said annular sliding mandrel means, said shear means comprising: first shear sleeve means having a plurality of apertures therein and engaging a portion of the irregular exterior surface of said sliding annular mandrel means; second shear sleeve means having a plurality of apertures therein substantially aligned with the plurality of apertures in the first shear sleeve means and engaging a portion of the irregular bore through said outer annular housing means; and shear pin means installed in the plurality of apertures in the first and second shear sleeve means, thereby preventing relative movement of the first shear sleeve means with respect to the second shear sleeve means until a predetermined amount of force is applied to said annular sliding mandrel means, the force being transferred from the portion of the irregular exterior surface of said sliding annular mandrel means to the first shear sleeve means causing the shear pin means to be sheared, thereby allowing relative movement between the first shear sleeve means and the second shear sleeve means.

Claim 14

The check valve assembly of claim 11 further comprising: locking dog means disposed within a portion of the irregular bore of the shear case means of said outer annular housing means and slidably engaging the end portion of the shear mandrel means secured to one end of the sealing mandrel means; and locking dog cavity means located in the irregular exterior surface of the shear mandrel means aft of the end of the shear mandrel means secured to the one end of the sealing mandrel means; whereby when said sliding annular mandrel means moves from the first position in said outer annular housing means, which allows communication through said second apertures from the bore of said outer annular housing means to the exterior thereof, to a second position within said outer annular housing where communication through the second apertures from the bore of said outer annular housing means to the exterior thereof is prevented by said sliding annular mandrel means, the locking dog means engage the locking dog cavity means to prevent movement of said sliding annular mandrel means from the second position within the outer annular housing means.

Claim 15

The check valve assembly of claim 11 wherein said sliding annular mandrel means comprises a pressure balanced sliding annular mandrel means.

Claim 16

In a drill stem testing string having a closed tester valve and a check valve assembly therebelow, the drill stem testing string being inserted into a fluid filled well bore having a preset packer therein, the check valve assembly relieving the fluid trapped between the preset packer and the closed tester valve as the testing string is being inserted into the preset packer, the check valve assembly comprising: outer annular housing means having first and second aperture means through the wall thereof and having an irregular bore therethrough; sliding annular mandrel means having an irregular exterior surface having annular shoulder means thereon disposed between the first and second aperture means through said outer annular housing means, said sliding annular mandrel means being slidably disposed in a first position within the bore of said outer annular housing means in sealing engagement therewith having the annular shoulder means of said sliding annular mandrel means communicating with the first aperture means of said outer annular housing means while the bore of said sliding annular mandrel means communicates with the second aperture means of said outer annular housing means; check valve seal means retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, said check valve seal means allowing communication from the bore of said outer annular housing means to the exterior thereof but preventing communication from the exterior of said outer annular housing means to the bore thereof; and shear means disposed within said outer annular housing means having a first portion thereof engaging a portion of the irregular exterior surface of said sliding annular mandrel means and having a second portion thereof engaging a portion of the irregular bore through said outer annular housing means, said shear means initially preventing movement of said sliding annular mandrel means with respect to said outer annular housing means when said sliding annular mandrel means is disposed within said outer annular housing means in a first position therein until a predetermined amount of force is applied to said annular sliding mandrel means.

Claim 17

In a drill stem testing string having a closed tester valve and a check valve assembly therebelow, the drill stem testing string being inserted into a fluid filled well bore having a preset packer therein, the check valve assembly relieving the fluid trapped between the preset packer and the closed tester valve as the testing string is being inserted into the preset packer, the check valve assembly comprising: outer annular housing means having first and second aperture means through the wall thereof and having an irregular bore therethrough; sliding annular mandrel means having an irregular exterior surface having annular shoulder means thereon disposed between the first and second aperture means through said outer annular housing means, said sliding annular mandrel means being slidably disposed in a first position within the bore of said outer annular housing means in sealing engagement therewith having the annular shoulder means of said sliding annular mandrel means communicating with the first aperture means of said outer annular housing means while the bore of said sliding annular mandrel means communicates with the second aperture means of said outer annular housing means; check valve seal means retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, said check valve seal means allowing communication from the bore of said outer annular housing means to the exterior thereof but preventing communication from the exterior of said outer annular housing means to the bore thereof; and shear means disposed within said outer annular housing means having a first portion thereof engaging a portion of the irregular exterior surface of said sliding annular mandrel means and having a second portion thereof engaging a portion of the irregular bore through said outer annular housing means, said shear means initially preventing movement of said sliding annular mandrel means with respect to said outer annular housing means when said sliding annular mandrel means is disposed within said outer annular housing means in a first position therein until a predetermined amount of force is applied to said annular sliding mandrel means.

Claim 18

The check valve assembly of claim 14 further comprising: locking dog means disposed within said outer annular housing means, said locking dog means allowing movement of said sliding annular mandrel means from the first position within said outer annular housing means.

Claim 19

The check valve assembly of claim 15 further comprising: locking dog cavity means disposed on said sliding annular mandrel means, said locking dog cavity means being disposed on said sliding annular mandrel means to allow movement of said sliding annular mandrel means from the first position within said annular housing means to a second position within said annular mandrel means, whereby said locking dog means engage said locking dog cavity means to prevent movement of said sliding annular mandrel means from the second position within said sliding annular housing means.

Claim 20

The check valve assembly of claim 16 further comprising: lug means on the exterior surface of one end of said sliding annular mandrel means; and longitudinal cavity means located in a portion of the irregular bore of said outer annular housing means slidably receiving said lug means of said sliding annular mandrel means therein.

Claim 21

The check valve assembly of claim 14 wherein said outer annular housing means comprises: annular adapter means having the second aperture means through the wall thereof and an irregular bore therethrough; annular shear case means having one end thereof secured to one end of the annular adapter means, the annular shear case means having an irregular bore therethrough; annular pressure housing means having one end thereof secured to the other end of the annular shear case means, having the first aperture means through the wall thereof and having an irregular bore therethrough, the annular pressure housing means receiving the annular shoulder means of said sliding annular mandrel means therein; and annular nipple means having one end secured to the other end of the annular pressure housing means, having an irregular bore therethrough and having longitudinal cavity means located in a portion of the irregular bore.

Claim 22

The check valve assembly of claim 18 wherein said sliding mandrel means comprises: annular sealing mandrel means having an irregular exterior surface thereon; and shear mandrel means secured to one end of the annular sealing mandrel means, the shear mandrel means having an irregular exterior surface thereon, having shear means abutment means on the end of the annular shear mandrel means secured to the annular sealing mandrel means, having annular shoulder means on the irregular exterior surface thereof and having lug means on the other end of the shear mandrel means, the lug means slidably engaging the longitudinal cavity means located in a portion of the irregular bore of the annular nipple means of said outer annular housing means.

Claim 23

The check valve assembly of claim 19 further comprising: locking dog means disposed within a portion of the irregular bore of the shear case means of said outer annular housing means and slidably engaging the end portion of the shear mandrel means secured to one end of the sealing mandrel means; and locking dog cavity means located in the irregular exterior surface of the shear mandrel means aft of the end of the shear mandrel means secured to the one end of the sealing mandrel means; whereby when said sliding annular mandrel means moves from the first position in said outer annular housing means, which allows communication through said second apertures from the bore of said outer annular housing means to the exterior thereof, to a second position within said outer annular housing where communication through the second apertures from the bore of said outer annular housing means to the exterior thereof is prevented by said sliding annular mandrel means, the locking dog means engage the locking dog cavity means to prevent movement of said sliding annular mandrel means from the second position within the outer annular housing means.

Claim 24

The check valve assembly of claim 20 wherein said shear means comprise: first shear sleeve means having a plurality of apertures therein engaging a portion of the irregular exterior surface of said sliding annular mandrel means; second shear sleeve means having a plurality of apertures therein substantially aligned with the plurality of apertures in the first shear sleeve means engaging a portion of the irregular bore through said outer annular housing means; and shear pin means installed in the plurality of apertures in the first and second shear sleeve means, thereby preventing relative movement of the first shear sleeve means with respect to the second shear sleeve means until a predetermined amount of force is applied to said annular sliding mandrel means, the force being transferred from the portion of the irregular exterior surface of said sliding annular mandrel means to the first shear sleeve means causing the shear pin means to be sheared, thereby allowing relative movement between the first shear sleeve means and the second shear sleeve means.

Claim 25

The check valve assembly of claim 14 wherein said check valve seal means comprises: an elastomeric skirt retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, the elastomeric skirt being radially expansible outwardly.

Claim 26

The check valve assembly of claim 14 wherein said sliding annular mandrel means comprises a pressure balanced sliding annular mandrel means.

Claim 27

In a drill stem testing string having a closed tester valve and a check valve assembly therebelow, the drill stem testing string being inserted into a fluid filled well bore having a preset packer therein, the check valve assembly relieving the fluid trapped between the preset packer and the closed tester valve as the testing string is being inserted into the preset packer, the check valve assembly comprising:

Claim 28

In a drill stem testing string having a closed tester valve and a check valve assembly therebelow, the drill stem testing string being inserted into a fluid filled well bore having a preset packer therein, the check valve assembly relieving the fluid trapped between the preset packer and the closed tester valve as the testing string is being inserted into the preset packer, the check valve assembly comprising:

Claim 29

outer annular housing means having first and second aperture means through the wall thereof and having an irregular bore therethrough, said outer annular housing means comprising: annular adapter means having the second aperture means through the wall thereof and an irregular bore therethrough; annular shear case means having one end thereof secured to one end of the annular adapter means and having an irregular bore therethrough; annular pressure housing means having one end thereof secured to the other end of the annular shear case means, having the first aperture means through the wall thereof and having an irregular bore therethrough; and annular nipple means having one end secured to the other end of the annular pressure housing means, having an irregular bore therethrough and having longitudinal cavity means located in a portion of the irregular bore; sliding annular mandrel means having an irregular exterior surface having annular shoulder means thereon disposed between the first and second aperture means through said outer annular housing means, said sliding annular mandrel means being slidably disposed in a first position within the bore of said outer annular housing means in sealing engagement therewith having the annular shoulder means of said sliding annular mandrel means communicating with the first aperture means of said outer annular housing means while the bore of said sliding annular mandrel means communicates with the second aperture means of said outer annular housing means, said sliding annular mandrel means comprising: annular sealing mandrel means having an irregular exterior surface thereon; and shear mandrel means secured to one end of the annular sealing mandrel means, the shear mandrel means having an irregular exterior surface thereon, having shear means abutment means on the end of the annular shear mandrel means secured to the annular sealing mandrel means, having annular shoulder means on the irregular exterior surface thereof and having lug means on the other end of the shear mandrel means, the lug means slidably engaging the longitudinal cavity means located in a portion of the irregular bore of the annular nipple means of said outer annular housing means; check valve seal means retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, said check valve seal means allowing communication from the bore of said outer annular housing means to the exterior thereof but preventing communication from the exterior of said outer annular housing means to the bore thereof, said check valve seal means comprising: an elastomeric skirt retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, the elastomeric skirt being radially expansible outwardly; and shear means disposed within said outer annular housing means having a first portion thereof engaging a portion of the irregular exterior surface of said sliding annular mandrel means and having a second portion thereof engaging a portion of the irregular bore through said outer annular housing means, said shear means initially preventing movement of said sliding annular mandrel means with respect to said outer annular housing means when said sliding annular mandrel means is disposed within said outer annular housing means in a first position therein until a predetermined amount of force is applied to said annular sliding mandrel means, said shear means comprising: first shear sleeve means having a plurality of apertures therein and engaging a portion of the irregular exterior surface of said sliding annular mandrel means; second shear sleeve means having a plurality of apertures therein substantially aligned with the plurality of apertures in the first shear sleeve means and engaging a portion of the irregular bore through said outer annular housing means; and shear pin means installed in the plurality of apertures in the first and second shear sleeve means, thereby preventing relative movement of the first shear sleeve means with respect to the second shear sleeve means until a predetermined amount of force is applied to said annular sliding mandrel means, the force being transferred from the portion of the irregular exterior surface of said sliding annular mandrel means to the first shear sleeve means causing the shear pin means to be sheared, thereby allowing relative movement between the first shear sleeve means and the second shear sleeve means.

Claim 30

outer annular housing means having first and second aperture means through the wall thereof and having an irregular bore therethrough, said outer annular housing means comprising: annular adapter means having the second aperture means through the wall thereof and an irregular bore therethrough; annular shear case means having one end thereof secured to one end of the annular adapter means and having an irregular bore therethrough; annular pressure housing means having one end thereof secured to the other end of the annular shear case means, having the first aperture means through the wall thereof and having an irregular bore therethrough; and annular nipple means having one end secured to the other end of the annular pressure housing means, having an irregular bore therethrough and having longitudinal cavity means located in a portion of the irregular bore; sliding annular mandrel means having an irregular exterior surface having annular shoulder means thereon disposed between the first and second aperture means through said outer annular housing means, said sliding annular mandrel means being slidably disposed in a first position within the bore of said outer annular housing means in sealing engagement therewith having the annular shoulder means of said sliding annular mandrel means communicating with the first aperture means of said outer annular housing means while the bore of said sliding annular mandrel means communicates with the second aperture means of said outer annular housing means, said sliding annular mandrel means comprising: annular sealing mandrel means having an irregular exterior surface thereon; and shear mandrel means secured to one end of the annular sealing mandrel means, the shear mandrel means having an irregular exterior surface thereon, having shear means abutment means on the end of the annular shear mandrel means secured to the annular sealing mandrel means, having annular shoulder means on the irregular exterior surface thereof and having lug means on the other end of the shear mandrel means, the lug means slidably engaging the longitudinal cavity means located in a portion of the irregular bore of the annular nipple means of said outer annular housing means; check valve seal means retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, said check valve seal means allowing communication from the bore of said outer annular housing means to the exterior thereof but preventing communication from the exterior of said outer annular housing means to the bore thereof, said check valve seal means comprising: an elastomeric skirt retained on the exterior of said outer annular housing means blocking the second aperture means of said outer annular housing means, the elastomeric skirt being radially expansible outwardly; and shear means disposed within said outer annular housing means having a first portion thereof engaging a portion of the irregular exterior surface of said sliding annular mandrel means and having a second portion thereof engaging a portion of the irregular bore through said outer annular housing means, said shear means initially preventing movement of said sliding annular mandrel means with respect to said outer annular housing means when said sliding annular mandrel means is disposed within said outer annular housing means in a first position therein until a predetermined amount of force is applied to said annular sliding mandrel means, said shear means comprising: first shear sleeve means having a plurality of apertures therein and engaging a portion of the irregular exterior surface of said sliding annular mandrel means; second shear sleeve means having a plurality of apertures therein substantially aligned with the plurality of apertures in the first shear sleeve means and engaging a portion of the irregular bore through said outer annular housing means; and shear pin means installed in the plurality of apertures in the first and second shear sleeve means, thereby preventing relative movement of the first shear sleeve means with respect to the second shear sleeve means until a predetermined amount of force is applied to said annular sliding mandrel means, the force being transferred from the portion of the irregular exterior surface of said sliding annular mandrel means to the first shear sleeve means causing the shear pin means to be sheared, thereby allowing relative movement between the first shear sleeve means and the second shear sleeve means.

Claim 31

The check valve assembly of claim 24 further comprising: locking dog means disposed within a portion of the irregular bore of the shear case means of said outer annular housing means and slidably engaging the end portion of the shear mandrel means secured to one end of the sealing mandrel means; and locking dog cavity means located in the irregular exterior surface of the shear mandrel means aft of the end of the shear mandrel means secured to the one end of the sealing mandrel means; whereby when said sliding annular mandrel means moves from the first position in said outer annular housing means, which allows communication through said second apertures from the bore of said outer annular housing means to the exterior thereof, to a second position within said outer annular housing where communication through the second apertures from the bore of said outer annular housing means to the exterior thereof is prevented by said sliding annular mandrel means, the locking dog means engage the locking dog cavity means to prevent movement of said sliding annular mandrel means from the second position within the outer annular housing means.

Claim 32

The check valve assembly of claim 24 wherein said sliding annular mandrel means comprises a pressure balanced sliding annular mandrel means.