Proceedings of the 2nd International Conference on Developments in Valves and Actuators for Fluid Control : Manchester, England: 28–30 March 1988

The flow of two-phase mixtures through restrictions. is a complex phenomenon that to date has not been fully described analytically. It is an area that received a geat deal of attention because of its application to nuclear reactor technology. The majority of the work done in this area considered ideal geometries such as nozzles, orifices and straight pipes. In the area of control valves very little work has been done. Brockett & King [1] studied subcooled water. Stiles [2] looked at subcooled freon. Martinec [4] compared subcooled freon in valves with ideal geometries. Sheldon & Schuder [3) looked experimentally at airjwater mixtures through valves that resulted in a sizing procedure. Fagerlund [10] presented an analytical model that required use of the Sheldon & Schuder data to establish the behavior of valves as opposed to more ideal geometries. However, the data used was limited to a single valve travel. Fagerlund & Storer [11] have expanded this to include several valve travels that further generalizes the technique. It is the intent of this paper to summarize a practical approach to s1z1ng valves for two-phase service that may be reduced to either a graphical or calculator procedure. Discussion of Analysis A fundamental assumption in this method is that the quality remains constant between the inlet and the vena contracta. For gas-liquid flows it is obvious providing vaporization does not occur. Front Matter....Pages i-xi A Variable Orifice Rotary Control Valve....Pages 1-6 Contiguous Sealing of Metal Seated Butterfly Valves....Pages 7-16 Testing of Valves and Actuators for Fire Environments....Pages 17-25 Cold Water Leak Detection in High Pressure Stainless Steel Isolation Valves Using Ultrasonic Noise Emission....Pages 27-43 Electronic Actuator Design....Pages 45-56 New Trends in Pneumatic Actuator Designs....Pages 57-66 Plug Vibrational Tendencies of Top Guided Throttling Control Valves....Pages 67-81 A One Dimensional Quasi-Steady Model for Prediction of Safety Valve Lift Characteristics....Pages 83-101 Use of Damping Devices to Control the Stability of Spring Loaded Safety Valves Operated in Liquid Service....Pages 103-114 The Development and Applications of Duplex Stainless Steel for Control Valve Equipment....Pages 115-135 New and Improved, High Nickel Alloy Castings....Pages 137-154 Developments in Soft Seated Trims for Control Valves....Pages 155-166 Engineering Thermoplastics in Actuator Construction....Pages 167-196 Sizing of Low Pressure Air Valves for Safe Filling and Draining of Pipelines....Pages 197-209 A Proposed Method of Control Valve Sizing for Non-Ideal Fluids....Pages 211-226 Predetermination of the Noise Emission of Valves in Fluid Service....Pages 227-239 Proposed Universal Method for Quantifying the Severity of a Cavitating Control Valve Service....Pages 241-256 Tests of Check Valves at EDF: Development of a Damped Check Valve....Pages 257-280 Check Valve Closure Behaviour; Experimental Investigation and Simulation in Waterhammer Computer Programs....Pages 281-300 Innovations in Non-Intrusive Testing and Trending of Motor Operated Valves and Check Valves....Pages 301-310 Qualification of French Pressurized Water Nuclear Power Stations Valves....Pages 311-328 Lubrication and Wear of Valve Headgear — A Case Study....Pages 329-347 Bellows Seals for Rotary (1/4 Turn) Valves....Pages 349-361 The control of bulk fluid flows in pipelines is essential for safe and efficient plant operation, whether the product is oil, gas, process liquid, chemicals or water. Problems such as leakage and valve jamming have been reported as common by offshore industrial users, who demand longer life and greater reliability. Manufacturers have responded with new concepts and new materials, including a variety of plastics, in an effort to meet the needs of complex modern systems operating at high temperatures and pressures. This meeting provided a forum for system designers, operators, manufacturers and researchers to discuss methods of improving valve performance and promoting better valve selection and specification. Ways in which the valve industry can use techniques, such as computer-aided-design and product quality monitoring, to keep pace with future developments, for example, subsea oil and gas stations, were also covered