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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
A reduced-bore ball valve has a smaller ball and smaller internals and requires less force or torque for opening and closing compared to a full-bore ball valve. A reduced-bore ball valve is typically considered the first choice for ball valve selection since it is more economical and cheaper than a full-bore ball valve. Valves are normally selected by valve and process engineers based on different parameters, like size, pressure, temperature, fluid type, application, etc. Although reduced bore is preferred over full bore for economic reasons, some conditions do not allow the usage of reduced-bore ball valves. The first condition is pressure drop and wearing inside the valve. If the pressure drop produced by a reduced-bore valve is high enough to cause flow assurance problems, then a reduced-bore ball valve should not be used. Process engineers are the correct references to give feedback on the acceptance of reduced-bore ball valves with regard to pressure drop.
Applications: Engineering with Ceramics
Published in David W. Richerson, William E. Lee, Modern Ceramic Engineering, 2018
David W. Richerson, William E. Lee
A valve performs the same function as a seal, but in an opening and closing mode rather than a continuous contact mode. There are many types of valves: rotary, gate, ball-and-seat, butterfly, and concentric cylinder, and each of these has many variations. One type of rotary valve consists of a ball with a hole through it and a rod or handle that protrudes from the side. The rod can be physically manipulated so that the hole either lines up with the pipe carrying the fluid (valve open) or so the hole faces the side wall (valve closed). This type of valve can control flow in both directions at any level between maximum and zero. A variant of this is the valve and seal for a sink faucet that has only a single handle. The valve and seal consists typically of alumina or silicon carbide pieces such as those shown in Figure 3.19. When you rotate the handle to the middle position, hot water comes in through one hole and cold through another and they mix to exit through another hole. If you rotate the handle all the way to one side, only one inlet hole is open so the water is either all hot or all cold. By controlling of the position of the handle you can achieve any mixture you desire of hot plus cold. A very smooth surface finish and excellent flatness between the ceramic contacting surfaces allows the valve to simultaneously perform as a seal, so no gasket is required. This is one of those hidden ceramic applications that you use all the time, but were probably never aware that ceramics were involved.
Pneumatic Systems
Published in Anton H. Hehn, Fluid Power Troubleshooting, 1995
Supply lubricated air. Most valves and the mechanisms they control require light lubrication. A good lubricator should put atomized oil into the air line in direct proportion to the rate of airflow. Either excessive or inadequate lubrication can cause the valve to malfunction. For most applications an oil flow rate of 1 drop per minute is adequate. Another lubrication check can be made by holding a piece of clean white paper near the valve’s exhaust port for three or four cycles. A properly lubricated valve will produce only a slight discoloration of the paper. Suitable lubricating oils must be compatible with the materials in the valve used for seals and poppets. Generally speaking, any light-bodied mineral- or petroleum-base oil with oxidation inhibitors, an aniline point between 82°C (180°F) and 104°C (220°F), and an SAE 10, or lighter, viscosity will prove suitable.
Numerical and Experimental Vibration Analysis of an Additive Manufactured Sensor Mounting Unit for a Wireless Valve Position Indication Sensor System
Published in Nuclear Technology, 2022
Sasa Kovacevic, Vivek Agarwal, John W. Buttles
Valve manipulation is regularly performed in NPPs to control, start, stop, regulate, and throttle the flow of different fluids through plant systems to achieve the desired performance and operating margins. The deployment, configuration, and manipulation (manual or automatic) of different valve types, including ball, butterfly, globe, gate, and check, depend on the mode of operation and the application. As part of the current nuclear industry’s business model, skilled workers regularly manipulate manual valves at an NPP. This also includes concurrent or independent verification of the performed action, whether closing, opening, throttling, or calibration. Manual performance of these tasks opens up (1) the possibility of human error, (2) operational and safety challenges, and (3) regulatory compliance impacts, in addition to high labor costs. NPPs have a giant catalog of manual valves and rely on technical staff for manual valve manipulation/verification, which puts generating stations at a long-term economic disadvantage due to the rising cost of labor. To improve the economic competitiveness of the nuclear industry, transition from the current labor-centric model to a technology-centric business model is required.
Mock circulatory test rigs for the in vitro testing of artificial cardiovascular organs
Published in Journal of Medical Engineering & Technology, 2019
To improve the haemocompatibility of a centrifugal blood pump, Nishida et al. carried out a flow visualisation study on a simple steady flow test rig [54]. In the test loop, a scaled-up motor model was driven by a DC motor. Two ports of the pump were connected to a reservoir. A valve controls the load and flow rate in the system. Two pressure transducers and a flow transducer were installed to monitor the basic system condition. water solution (by weight) was used as a working fluid, and by weight was used as the stabiliser. To measure the fluid flow, the fluid profile in the motor was illuminated by Argon Ion laser, and a high-speed video camera was used to record the flow evolution.
Solving mixed-integer nonlinear programmes using adaptively refined mixed-integer linear programmes
Published in Optimization Methods and Software, 2020
Robert Burlacu, Björn Geißler, Lars Schewe
A valve is a controllable element in a gas network, which can either be closed or open. A closed valve impedes gas from passing, which leads to decoupled pressures at nodes u and v. On the contrary, for open valves, we have and no pressure drop. Valves are modelled with the help of binary switching variables , whereby is equal to one, if and only if the valve is open and vice versa: