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Valve seats are often formed by first press-fitting an approximately cylindrical piece of a hardened metal alloy, such as Stellite, into a cast depression in a cylinder head above each eventual valve stem position, [1] and then machining a conical-section surface into the valve seat that will mate with a corresponding conical section of the ...
The upper part of the valve stem, within the rocker box, is lubricated by oil. If this oil travels unchecked along the valve stem, engine HC emissions will become excessive. To control this, an elastomeric seal is fitted over the top of the valve guide. These may wear or stiffen with age, so are usually replaced whenever valves are removed for ...
Multi-seat valve with pneumatic actuator. Multi-seat valves, or multi-port valves, are used to shut off or control complex liquid flows in sterile areas in the beverage and food industry as well as in the fine chemical and pharmaceutical industry. Multi-seat valves often replace combinations of several single-seated valves in aseptic processing.
Arc-based cutting methods are used for cutting these materials. Among these, plasma arc cutting is the most commonly employed technique, owing to its precision and ability to cut through high-alloy steels efficiently. [1] Thermal cutting creates a shallow region contaminated material adjacent to the cut surfaces - the heat affected zone. For ...
A rapid prototyping machine using selective laser sintering (SLS) 3D model slicing. Rapid prototyping is a group of techniques used to quickly fabricate a scale model of a physical part or assembly using three-dimensional computer aided design data.
Globe valve. A globe valve, different from ball valve, is a type of valve used for regulating flow in a pipeline, consisting of a movable plug or disc element and a stationary ring seat in a generally spherical body. [1] Globe valves are named for their spherical body shape with the two halves of the body being separated by an internal baffle.
MAPP gas can be used at much higher pressures than acetylene, sometimes up to 40 or 50 psi in high-volume oxy-fuel cutting torches which can cut up to 12-inch-thick (300 mm) steel. Other welding gases that develop comparable temperatures need special procedures for safe shipping and handling.
The poppet valve is different from both slide and oscillating valves. Instead of sliding or rocking over a seat to uncover a port, the poppet valve lifts from the seat with a movement perpendicular to the plane of the port. The main advantage of the poppet valve is that it has no movement on the seat, thus requiring no lubrication. [7]