Detailed structural description:
1. Applicable temperature range: -46℃～150℃ (LF2 body) -29℃～150℃ (A105 body); Applicable media: natural gas, oil, etc.
2. Valve type: forged steel split type/bolted connection
3. Structural length: in accordance with API 6D specification.
4. Diameter: full diameter and reduced diameter types meet the requirements of the technical specifications and ball valve data sheet.
5. Connection end: Flange end: convex flange in accordance with ANSI B16.5. Welding end: welding groove size meets the requirements of ASME B31.8. And add transition sections (sleeves) at both ends according to the requirements of the ball valve data sheet
6. Design: The valve design follows the standards, specifications and regulations listed in Article 2 of this technical proposal. The minimum wall thickness of the pressure-bearing parts meets the requirements of Part VIII of the ASME Boiler and Pressure Vessel Code and ANSI/ASME B16.34. The valve has sufficient strength and rigidity, and the selection of materials fully guarantees the compatibility and weldability with the corresponding pipelines and pipe fittings.
7. Valve body: Split cast steel (or forged steel) valve body, the side valve body and the main valve body are connected by studs/nuts, and the joint is designed with a fireproof gasket, and has sufficient bending strength to withstand pipeline stress.
8. Gland: The gland is bolted to the valve body, which is convenient for the removal and installation of the valve stem components, and the second seal of the valve stem can be replaced without affecting the operation of the valve on the pipeline. The size design of the coupling plate meets the requirements of the ISO 5211 standard, which is convenient for the installation and interchange of manual, electric and gas/liquid linkage drives. The gland and bottom cover are designed with fireproof gaskets at the connection with the valve body.
9. Ball: Forged steel ball, fixed type; a damping balanced check valve is set on the top of the ball. The factory's unique envelope grinding ball forming process is adopted. The ball has high precision. The surface of the ball is chemically nickel-plated. The minimum thickness of the coating is 40μm and the minimum hardness is HV800~1000.
10. Valve stem: Separated from the ball, the valve stem is designed as a shoulder-type anti-flying structure according to the ASME B16.3 standard. The friction part of the valve stem is covered with a plastic bearing to reduce the operating torque of the valve. In order to improve the surface hardness of the valve stem, chemical nickel plating is used, the minimum thickness of the coating is 40μm, and the minimum hardness is HV800~1000.
11. Valve stem seal: The first seal is an "O" type seal ring (VITON-A), and the second seal is a fireproof seal ring (expanded graphite). The second seal of the valve stem can be replaced under pressure. And it can ensure the sealing of the valve stem rotating part in the fire state.
12. Valve seat structure: The valve seat adopts a metal + VITON hybrid design. The first-level seal is achieved by the metal-to-metal connection between the valve seat and the ball; the second-level seal is achieved by the elastic material to the ball to achieve absolute zero leakage. In this design, the hard particles in the medium cannot be embedded in the first-level metal sealing surface; nor can they be embedded in the second-level elastic material. The elastic material will deform with the extrusion of the hard particles. When the valve is opened next time, the hard particles will pop out from the surface of the valve seat; if the hard particles are indeed embedded in the elastic seal, they will also be absorbed by the elasticity of the elastic sealing surface, and will not scratch the strength of the ball, so there will be no mechanical damage. The anti-erosion method of the elastic sealing surface is just like the steel fence of the sandblasting room must be protected by rubber pads to prevent erosion. The erosion energy is absorbed by deformation and then rebounded. This reduces erosion and wear.