An automatic ring valve comprising a valve seat provided with a plurality of gas flow passages arranged according to at least one annular row, at least a shutter comprising at least one ring-shaped portion for selectively closing and opening the gas flow passages, wherein the ring-shaped portion of the shutter comprises a fiber-reinforced matrix, at least one contrasting member for contrasting an opening movement of ring-shaped portion of the shutter, wherein the ring-shaped portion of the shutter comprises continuous fibers, at least some of the fibers developing for at least 360? of the annular development of the ring-shaped portion.

A method for measuring a wall thickness in hollow valves may include determining a wall thickness in a region of a valve stem using at least one ultrasonic sensor, wherein the one ultrasonic sensor may be oriented with respect to a surface on the valve stem in such a manner that an emitted ultrasound may be introduced into the surface in a perpendicular manner. The method may additionally or alternatively include determining a wall thickness in a region of a chamfer using the at least one ultrasonic sensor, wherein the at least one ultrasonic sensor may be positioned at a location on the chamfer at which an inner tangent in a cavity runs parallel to an outer tangent on the chamfer, and wherein the ultrasonic sensor is oriented with respect to the tangents in such a manner that an emitted ultrasound is introduced into the surface in a perpendicular manner.

An exhaust valve for an internal combustion engine comprises a valve disc having a first side (14) and a second side (16), a valve stem extending from the first side of the valve disc, and an annular valve seat area (11) located at the first side of the valve disc. The annular valve seat area (11) is of a nickel-base alloy or a chromium-base alloy and has a valve seat surface. The annular valve seat area has at least a first annular portion (43) located in between two second annular portions (42). The first annular portion has lower hardness than the two second annular portions.

The present invention is provided with: an umbrella part metallic sodium insertion device for inserting rod-shaped metallic sodium into a hollow part of a hollow valve; a melting device for melting the metallic sodium in the hollow part by inserting a push rod from an opening into the hollow part of the hollow valve, in which the metallic sodium has been inserted by the device, and, while pushing the rod-shaped metallic sodium in the hollow part, heating the umbrella part to a temperature at which the metallic sodium is melted; a stem part cooling device for cooling a stem part of the hollow valve, in which the metallic sodium has been melted by the melting device, to a temperature lower than the temperature at which the metallic sodium is melted; and a stem part metallic sodium insertion device for inserting rod-shaped metallic sodium into the hollow part which has been cooled by the device.

Each time a highly-viscous substance is extruded, a variation in weight of each cut piece of the highly-viscous substance is minimized. Metallic sodium (5) loaded in an extruder main body (3) is extruded from a nozzle (7) of the extruder main body (3) with a pressing tool (4) and, when it is detected that the metallic sodium (5) is extruded to a predetermined position, the movement of the pressing tool (4) is stopped and the extruded metallic sodium (5) is cut. In this case, an impulse (P) after stop is brought closer to a constant value until a load no longer acts on the metallic sodium (5) in the extruder main body (3) after stopping the movement of the pressing tool (4) by adjusting the movement speed of the pressing tool (4).

A snap-action valve assembly for an exhaust system includes a valve flap positioned within a conduit. A shaft supports the valve flap in the conduit for rotation about a pivot axis between a closed position and an open position. A roller is supported for rotation on a post. The post is fixed to the shaft by a lever arm. A torsion spring includes a first end coupled to the conduit and a second end coupled to the roller. The torsion spring is preloaded to urge the valve flap into contact with an inner surface of the conduit when the valve flap is in the closed position. A method of assembling the snap-action valve assembly with a predetermined spring preload torque is also discussed.

A snap-action valve assembly includes a valve flap positioned within a conduit for controlling exhaust flow through the conduit. A shaft supports the valve flap in the conduit for rotation about a pivot axis between a closed position and an open position. A guide is fixed to the valve flap. A torsion spring is positioned at least partially outside the conduit and includes a first end restricted from rotation in at least one direction. The torsion spring includes a second end coupled to the guide. The torsion spring is preloaded to urge the valve flap into contact with an inner surface of the conduit when the valve flap is in the closed position.

A precision forming method of a high-efficiency and near-net hollow valve blank of an engine is provided, wherein the precision performing is realized by the cross wedge rolling mold, under the rolling the metal tubing for the valve deforms, with a middle part sunken and two ends elongating, the middle part forms a stem part of a hollow valve, the two ends form disk parts to be machined, and the connection sections between the disk parts and the stem part form neck parts having arced concave faces and a frustoconical lateral face in structure, achieving better consistency among the acquired hollow valve blanks. The disk part of each acquired hollow valve preformed blank is machined by the die-forging forming mold that is matched with the disk structure of the manufactured hollow valve, the hollow valve preformed blank is directly placed in the cavities of the die-forging forming mold for forging.

A method for making a valve stem seal, comprising the steps of providing a metal retainer having a top portion and a body portion. The body portion having a first section and a second section. In a first state, the first section of the body portion is cylindrical and the second section of the body portion is cone shaped. Providing a hollow mold. Inserting the metal retainer into the outer mold piece, inserting the inner mold piece into the metal retainer, and then securing the inner and outer mold pieces to each other. Filling a cavity around the top portion of the metal retainer with an elastomeric compound. Removing the metal retainer and the formed rubber sealing element from the mold pieces, and pressing downward over the formed valve stem seal to compress the second section of the body portion radially inwardly.

An improved membrane valve and method for manufacturing such membrane valve. The improved membrane valve can be used for transferring fluids or gases in hermetic or semi-hermetic compressors, including a method and system for manufacturing a membrane valve and a membrane valve with applications for use in several motors, particularly in hermetic or semi-hermetic compressors which use, as a refrigeration fluid, an appropriate type of gas thus promoting the refrigeration physical affect. A body and a membrane of the membrane valve are produced from substantially thin metallic plates separately in accordance to an available process and can be subjected to rounding in order to eliminate live corners, and then juxtaposed thus composing the valve, with the above mentioned membrane on one side, fitted to the body which is fixed through a connection process and, on the other side, left free to oscillate.