A flapper check valve employed to prevent flow up the work string while allowing flow down the work string and into the well is disclosed. The check valve is activated by a compression spring, which then acts on a ball which will further act on a cam profile attached to the back of a flapper. The apparatus causes the flapper to default to the closed position when the flow is stopped, regardless of the position of the valve, even when gravity is acting against the flapper. The compression spring also allows for an apparatus which possesses lower operating stresses on the spring.

A flapper check valve employed to prevent flow up the work string while allowing flow down the work string and into the well is disclosed. The check valve is activated by a compression spring, which then acts on a ball which will further act on a cam profile attached to the back of a flapper. The apparatus causes the flapper to default to the closed position when the flow is stopped, regardless of the position of the valve, even when gravity is acting against the flapper. The compression spring also allows for an apparatus which possesses lower operating stresses on the spring.

A check valve comprises a valve housing defining an opening and a plurality of flapper elements each having a proximal end and a distal end. The flapper elements are pivotally mounted to the valve housing at their proximal ends for pivotal movement between a closed position, in which they block the flow of fluid through the opening and an open position in which they permit the flow of fluid through the opening. Each flapper element is generally triangular or trapezoidal in shape such that the flapper elements together create a generally conical or frustoconical surface when the valve is in the closed position. A resilient band extending around a circumference of the conical or frustoconical surface defined by the plurality of flapper elements in the closed position for biasing the flapper elements towards the closed position.

A blow case with an inlet pipe positioned to gravity direct debris to an outlet pipe. The inlet pipe having a discharge end sealed by gravity open clapper style check valve that is closed by activation of pneumatic pressure through a float style pneumatic valve. The check valve has a top mounted access port and aperture allowing for direct above ground servicing access to both the clapper inside the valve and has a removable clapper and access port for servicing the outlet pipe. The float style pneumatic valve is also top mounted for ease of service and removal and is remotely positioned from the outlet pipe to allow for removal of the valve for flushing of the debris from the blow case.

A damper valve assembly for an exhaust system of a vehicle includes a valve housing and a valve flap. The valve housing is adapted to be attached to a pipe of the exhaust system and defines an opening. The valve flap is rotatable relative to the valve housing and about a pivot axis between a first position whereat fluid flow through the opening of the valve housing is restricted and a second position whereat fluid flow through the opening of the valve housing is allowed. The valve flap includes a body and a mass damper. The mass damper is integral with the body and includes a plurality of segments that are folded so that the plurality of segments are in a stacked arrangement.

A damper valve assembly for an exhaust system of a vehicle includes a valve housing and a valve flap. The valve housing is adapted to be attached to a pipe of the exhaust system and defines an opening. The valve flap is rotatable relative to the valve housing and about a pivot axis between a first position whereat fluid flow through the opening of the valve housing is restricted and a second position whereat fluid flow through the opening of the valve housing is allowed. The valve flap includes a body and a mass damper. The mass damper is integral with the body and includes a plurality of segments that are folded so that the plurality of segments are in a stacked arrangement.

A link couples a support body and a valve body in a first arrangement where a first link-forming member is rotationally movably supported by the support body and in which a second link-forming member is rotationally movably supported by the valve body. The link includes: a link length that is a length of the first link-forming member, as measured between a rotation axis with respect to the support body and a rotation axis with respect to the second link-forming member; and a link length that is a length of the second link-forming member, as measured between a rotation axis with respect to the valve body and a rotation axis with respect to the first link-forming member. The link lengths differ from each other. The link is also configured to enable coupling between the support body and the valve body in a second arrangement inverted with respect to the first arrangement.

A check valve comprises a valve housing defining an opening and a plurality of flapper elements each having a proximal end and a distal end. The flapper elements are pivotally mounted to the valve housing at their proximal ends for pivotal movement between a closed position, in which they block the flow of fluid through the opening and an open position in which they permit the flow of fluid through the opening. Each flapper element is generally triangular or trapezoidal in shape such that the flapper elements together create a generally conical or frustoconical surface when the valve is in the closed position. A resilient band extending around a circumference of the conical or frustoconical surface defined by the plurality of flapper elements in the closed position for biasing the flapper elements towards the closed position.

A link couples a support body and a valve body in a first arrangement where a first link-forming member is rotationally movably supported by the support body and in which a second link-forming member is rotationally movably supported by the valve body. The link includes: a link length that is a length of the first link-forming member, as measured between a rotation axis with respect to the support body and a rotation axis with respect to the second link-forming member; and a link length that is a length of the second link-forming member, as measured between a rotation axis with respect to the valve body and a rotation axis with respect to the first link-forming member. The link lengths differ from each other. The link is also configured to enable coupling between the support body and the valve body in a second arrangement inverted with respect to the first arrangement.

A blow case with an inlet pipe positioned to gravity direct debris to an outlet pipe. The inlet pipe having a discharge end sealed by gravity open clapper style check valve that is closed by activation of pneumatic pressure through a float style pneumatic valve. The check valve has a top mounted access port and aperture allowing for direct above ground servicing access to both the clapper inside the valve and has a removable clapper and access port for servicing the outlet pipe. The float style pneumatic valve is also top mounted for ease of service and removal and is remotely positioned from the outlet pipe to allow for removal of the valve for flushing of the debris from the blow case.