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Valve and Actuator Technology for the Offshore Industry
Published in Karan Sotoodeh, Coating Application for Piping, Valves and Actuators in Offshore Oil and Gas Industry, 2023
Butterfly valves are the other group of valves that are used for flow isolation or on/off application. But it is important to know that butterfly valves can be used for flow control or regulation as well. Like ball and plug valves, butterfly valves are quarter-turn valves that move between open and closed positions with just a 90° stem and closure member (disk) rotation. The quarter-turn design of butterfly valves makes them easy to operate. In addition, butterfly valves require less force or torque for operation compared to ball valves, as they have a relatively low-mass disk compared to the ball inside a ball valve. The advantage of butterfly valves over ball, gate and plug valves is that they are lighter, cheaper and consume less space. In addition, butterfly valves can be designed and produced in a wafer-type (flangeless body) design, which reduces the weight of the valve significantly. Figure 5.37 illustrates wafer-type butterfly valves, shown in blue, placed between two flanges in a piping system. All the valves in Figure 5.37 are in open position since the levers are parallel to the pipe. Figure 5.38 compares a wafer-type rubber-lined butterfly valve in open and closed positions. Figure 5.39 shows a butterfly valve with flange connections on both sides, which is heavier and takes up more space compared to a wafer-type (flangeless body) butterfly valve.
Water/Wastewater Conveyance
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
Figure 8.35 shows a cross-sectional view of a butterfly valve. The valve itself consists of a body in which a disk (butterfly) rotates on a shaft to open or close the valve. Butterfly valves may be flanged or wafer design, the latter intended for fitting directly between pipeline flanges. In the full open position, the disk is parallel to the axis of the pipe and the flow of fluid. In the closed position, the disk seals against a rubber gasket-type material bonded either on the valve seat of the body or on the edge of the disk. Because the disk of a butterfly valve stays in the fluid path in the open position, the valve creates more turbulence (higher resistance to flow—equaling a higher pressure loss) than a gate valve. On the other hand, butterfly valves are compact. They can also be used to control flow in either direction. This feature is useful in water treatment plants that periodically backwash to clean filter systems.
Dimensional Analysis and Dynamic Similitude
Published in William S. Janna, Introduction to Fluid Mechanics, Sixth Edition, 2020
It is desired to conduct some tests on a butterfly valve. A butterfly valve is merely a disk, with a shaft attached, that is located within a pipeline. The disk outside diameter and the inside diameter of the pipeline are approximately equal. Rotating the shaft will cause the disk to rotate and block the flow area with an adequate seal. We want to determine the electric motor power required to automatically close the valve. The motor power P˜ required is a function of the maximum torque encountered To , the desired rotational speed ω, the mass of the disk m, the average velocity of the flow V, the disk diameter D, and density ρ and viscosity μ of the fluid. Using dimensional analysis, develop an expression to relate these variables.
Safety and reliability analysis for butterfly valves in the offshore oil and gas industry
Published in Safety and Reliability, 2022
A description of the novelty of this research is provided in this paragraph. To do this, what is already known through reviewed literatures as well as their limitations are highlighted in this section. According to the reviewed literature, the following is already known about safety and reliability for piping and industrial valves in the offshore oil and gas industry:The FMEA and SIL study has been performed for the pipeline valves connected to the safety instrumented system (SIS) located on an offshore platform. A combination of FMEA and SIL is used to evaluate the reliability of the valves in addition to reducing associated risks through risk prevention measures. It should be noted, however, that this study fails to address butterfly valves.A study of the SIL of the HIPPS system including three actuated valves used to reduce emissions to the environment from flare systems. A HIPPS system consists of three ball or axial valves connected in series. Accordingly, SIL studies are not conducted for butterfly valves as in previous studies, which is considered to be a major gap.Another past study based on the reviewed literature evaluates butterfly valves as lighter, cheaper and more compact valves than ball valves. However, the study does not include any reliability analysis for the butterfly valves.Similarly, a recent study focuses on condition monitoring, or ValveWatch, to improve the safety and reliability of actuated valves connected to SIS, although it does not directly address butterfly valves.