A check valve comprises an annular housing defining a generally circular opening. A plurality of radially extending arms extend across the circular opening from the centre of the valve housing to respective nodes at the periphery of the valve housing. A plurality of cross arms extend between circumferentially adjacent nodes, thereby dividing the circular opening into a plurality of primary, generally triangular radially inner openings and a plurality of secondary, generally segment shaped radially outer openings. A plurality of primary, generally triangular flapper elements close the primary openings and a plurality of secondary, generally segment shaped flapper elements close the secondary openings. Respective mounting posts are arranged at a respective node and a respective hinge pin is mounted between respective circumferentially adjacent mounting posts.

A valve mechanism includes a valve (a butterfly valve 30) arranged in a path in which gas flows, a drive shaft (32) coupled to the valve, and a lever member (33) attached to a lever attachment portion (321) provided at the drive shaft. The lever attachment portion of the drive shaft has a non-circular cross-sectional shape. The lever member has a through-hole (331) in a shape corresponding to a non-circular cross section of the lever attachment portion, and is fitted onto the lever attachment portion. The lever member is fixed to the drive shaft in such a manner that a first contact portion (a first contact member 34) and a second contact portion (323) sandwich the lever member in an axial direction of the drive shaft.

An aspect includes an offset parallel valve system that includes a first valve body and a first valve disc operably disposed within the first valve body. The offset parallel valve system also includes a second valve body in parallel with the first valve body and a second valve disc operably disposed within the second valve body, where the second valve disc is laterally offset from the first valve disc. A linkage system is operably coupled to the first valve disc and the second valve disc. The linkage system includes an armature coupled to a grooved linkage member having a first groove and a second groove. The first groove delays movement of the second valve disc as the first valve disc rotates, and the second groove controls a rotation angle of the second valve disc.

An aspect includes a globe butterfly valve that includes a valve inlet, a valve outlet, a globe housing with a spherical body between the valve inlet and the valve outlet, and a globe butterfly valve disc operably disposed within the globe housing. The globe housing has a larger interior diameter than an inlet diameter of the valve inlet and an outlet diameter of the valve outlet. The globe butterfly valve disc is configured to block a flow path between the valve inlet and the valve outlet responsive to an outer edge of the globe butterfly valve disc being positioned proximate to an interior surface of the globe housing between the valve inlet and the valve outlet.

An aspect includes an offset parallel valve system that includes a first valve body and a first valve disc operably disposed within the first valve body. The offset parallel valve system also includes a second valve body in parallel with the first valve body and a second valve disc operably disposed within the second valve body, where the second valve disc is laterally offset from the first valve disc. A linkage system is operably coupled to the first valve disc and the second valve disc. The linkage system includes an armature coupled to a grooved linkage member having a first groove and a second groove. The first groove delays movement of the second valve disc as the first valve disc rotates, and the second groove controls a rotation angle of the second valve disc.

An aspect includes a dual valve system that includes a first valve body and a first valve disc operably disposed within the first valve body, where the first valve disc has a first disc geometry. The dual valve system also includes a second valve body and a second valve disc operably disposed within the second valve body, where the second valve disc has a second disc geometry. The dual valve system further includes a mechanical linkage operably coupled to the first valve disc and the second valve disc, where the second disc geometry differs from the first disc geometry such that opening of a first flow area between the first valve body and the first valve disc occurs prior to opening of a second flow area between the second valve body and the second valve disc responsive to movement of the mechanical linkage.

A bypass feature and an emergency shutdown valve that includes such a bypass feature, which is selectively operable to permit a flow of material to pass through the emergency shutdown valve when a shutoff element thereof is closed so as to otherwise prohibit flow through the valve, as well as an associated method of testing an emergency shutdown valve.

An adjustment device designed to adjust a flow rate of a fluid flowing in a duct, including a body in which an adjustment valve is mounted, movable in rotation about an adjustment axis, the body having an area upstream of the adjustment axis and a downstream area opposite to the upstream area with respect to the adjustment axis, where the adjustment axis is equipped with connecting means which cooperate with at least one first control member positioned in the downstream area and a second control member positioned in the upstream area.

A valve seat (10) comprises a substantially annular rigid scaffold member (12) and a substantially annular elastomeric sealing member (14) sealingly mounted on top of the rigid scaffold member. The valve seat has an outer peripheral surface for cooperation with the valve body of a valve assembly, and the elastomeric sealing member defines an inner sealing surface of the valve seat for cooperation with a valve closure disc of a valve assembly.

An airflow valve may comprise a plate assembly located inside an airflow conduit. An actuator may be attached to, and/or otherwise fixed relative to, a plate of the plate assembly. The actuator may be coupled to the airflow conduit. If activated, the actuator may react against the airflow conduit to induce rotation of the plate.