This disclosure provides a box lid and an airtight box and belongs to the technical field of food preservation boxes. The box lid comprises: a lid body; and a sealing ring connected to the lid body, the sealing ring comprising an inclined portion inclined inwards, wherein the inclined portion can produce elastic deformation and is deformable to a sealing state. The beneficial effects of this disclosure are as follows: The specially designed sealing ring allows the airtight box to maintain an airtight effect when the interior is in a positive pressure environment, so the airtight box does not need air release after being sealed. When the box lid reaches the sealing position from the contact position, the air pressure in the box increases to assist the inclined portion of the sealing ring to achieve sealing.

An aircraft includes first and second zones, and a sealing system, interposed between a doorframe and a door providing access to the second zone, including: a peripheral seal secured to the door, a stop secured to the doorframe, and including a body in the form of at least one plate which extends around the perimeter of the doorframe, parallel to the door when the door is in the closed position, a peripheral groove positioned on the stop in such a way that the peripheral seal closes off the peripheral groove around the perimeter of the opening when the door is in the closed position, and at least one passage configured to cause the peripheral groove and the first zone to communicate.

An aircraft includes first and second zones, and a sealing system, interposed between a doorframe and a door providing access to the second zone, including: a peripheral seal secured to the door, a stop secured to the doorframe, and including a body in the form of at least one plate which extends around the perimeter of the doorframe, parallel to the door when the door is in the closed position, a peripheral groove positioned on the stop in such a way that the peripheral seal closes off the peripheral groove around the perimeter of the opening when the door is in the closed position, and at least one passage configured to cause the peripheral groove and the first zone to communicate.

The disclosure relates to a butterfly valve having a valve opening defined through the valve body and including a seat retainer fastened to the valve body; a disc with an optimized profile rotatably mounted within the valve opening; an interstice between the disc and valve body; a valve seat cavity defined in the seat retainer and the valve body; a fluid port defined in the valve body, wherein the fluid port is connected to the valve seat cavity and the interstice.

The disclosure relates to a butterfly valve having a valve opening defined through the valve body and including a seat retainer fastened to the valve body; a disc with an optimized profile rotatably mounted within the valve opening; an interstice between the disc and valve body; a valve seat cavity defined in the seat retainer and the valve body; a fluid port defined in the valve body, wherein the fluid port is connected to the valve seat cavity and the interstice.

A recessed part formed on a side surface includes a dynamic pressure part extending in the circumferential direction to converge on the side surface, and an introduction part extending from the dynamic pressure to open the dynamic pressure part toward the inner periphery side. One or two inner peripheral wall parts are provided for each of the recessed parts. The inner peripheral wall part is a portion defined on the inner periphery side of the corresponding recessed part by the dynamic pressure part and the introduction part. The inner peripheral wall part includes an inner peripheral wall surface. The inner peripheral wall surface extends toward the introduction part in the circumferential direction with inclining with respect to the side surface such that the inner peripheral wall surface is depressed from the side surface.

A sealing device in which diameter expansion of an inserted first back-up ring is suppressed. The sealing device includes a seal ring mounted in a rectangular mounting groove, the first back-up ring, and a second back-up ring. The first back-up ring has an end surface contacting an opposing-sealing-fluid-side side surface of the mounting groove. The second back-up ring has an end surface contacting the seal ring. A contact surface in an inner peripheral end of second back-up ring is perpendicular to the axis to contact an opposing-sealing-fluid-side side surface of the mounting groove. The inner diameter of the first back-up ring is set to be larger than the outer diameter of the contact surface portion of the second back-up ring, and the outer diameter of the first back-up ring is set to be smaller than the inner diameter of a housing.

A sealing device in which diameter expansion of an inserted first back-up ring is suppressed. The sealing device includes a seal ring mounted in a rectangular mounting groove, the first back-up ring, and a second back-up ring. The first back-up ring has an end surface contacting an opposing-sealing-fluid-side side surface of the mounting groove. The second back-up ring has an end surface contacting the seal ring. A contact surface in an inner peripheral end of second back-up ring is perpendicular to the axis to contact an opposing-sealing-fluid-side side surface of the mounting groove. The inner diameter of the first back-up ring is set to be larger than the outer diameter of the contact surface portion of the second back-up ring, and the outer diameter of the first back-up ring is set to be smaller than the inner diameter of a housing.

A seal assembly configured to seal against a surface of a seal depressor is disclosed. The seal assembly includes a body member configured to elastically expand from an original state into an expanded state. The body member exerts a sealing pressure against the surface of the seal depressor when in the expanded state. The seal assembly also includes one or more actuation members constructed from a shape memory material having a high energy state and a low energy state. The one or more actuation members are configured to urge the body member of the seal assembly from the original state into the expanded state when the shape memory material transitions from the low energy state to the high energy state.

A gasket has an annular gasket base extending circumferentially about a gasket axis. A central flange extends inwardly away from the gasket base toward the gasket axis. The central flange has an apex positioned at a first distance from the gasket axis. A first arm is spaced apart from the central flange and extends radially and inwardly away from the gasket base toward the gasket axis. The first arm includes a first sealing portion. The first sealing portion defines a first sealing surface spaced apart from the gasket axis by a second distance which is greater than the first distance. A second arm is spaced apart from the central flange and extends radially and inwardly away from the gasket base toward the gasket axis. The second arm includes a second sealing portion defining a second sealing surface.