An actuator is a machine or component installed on the top of an industrial valve for automatically moving and controlling the valve.The performance of a valve is largely dependent on its actuator.An actuator can be h...An actuator is a machine or component installed on the top of an industrial valve for automatically moving and controlling the valve.The performance of a valve is largely dependent on its actuator.An actuator can be hydraulic,pneumatic,or electrical.This paper focuses on hydraulic actuators,which are common for large size and high-pressure class ball valves.Hydraulic actuators can be either single-acting(spring return)or double-acting.Single-acting actuators return to safe mode in case of failure.However,double-acting actuators have a fail-as-is function and cannot keep the valves open or closed in case of failure.This research used a combination of theoretical and experimental approaches.The paper discusses two case studies in offshore industry projects in which double-acting hydraulic actuators were selected instead of single-acting,and possible design impacts are discussed.A theoretical review is given in three papers about operating torque for ball valves,optimization of shutdown valve actuator weight,and design and analysis of hydraulic actuators.These three papers were selected for review to connect the valve required torque with actuator sizing and selection,finding practical approaches to optimize the actuator weight as well as develop a theoretical model to calculate the actuator thickness and dimensions for the 38”CL1500 ball valve in the Johan Sverdrup project.The proposed formulas and calculations used for sizing the 38”CL1500 ball valves were validated through a finite element analysis model.展开更多
It is difficult to obtain the desired strip shape using Sendzimir rolling mills because small diameter work rolls can be easily deformed by the roiling force. To control the strip shape effectively, it is important to...It is difficult to obtain the desired strip shape using Sendzimir rolling mills because small diameter work rolls can be easily deformed by the roiling force. To control the strip shape effectively, it is important to understand the relationship between the behavior of the shape actuator and the variation of the strip shape. A numerical model based on the contact element method was proposed for the prediction of strip shape. In this numerical model, the re- lationships between the actuating forces, the roll deflections, the thickness profiles of the entry and exit sides, and the strip shape were considered. The proposed numerical model for strip shape prediction was evaluated by computer simulation and experiment with respect to various AS-U roll and first intermediate roll positions.展开更多
文摘An actuator is a machine or component installed on the top of an industrial valve for automatically moving and controlling the valve.The performance of a valve is largely dependent on its actuator.An actuator can be hydraulic,pneumatic,or electrical.This paper focuses on hydraulic actuators,which are common for large size and high-pressure class ball valves.Hydraulic actuators can be either single-acting(spring return)or double-acting.Single-acting actuators return to safe mode in case of failure.However,double-acting actuators have a fail-as-is function and cannot keep the valves open or closed in case of failure.This research used a combination of theoretical and experimental approaches.The paper discusses two case studies in offshore industry projects in which double-acting hydraulic actuators were selected instead of single-acting,and possible design impacts are discussed.A theoretical review is given in three papers about operating torque for ball valves,optimization of shutdown valve actuator weight,and design and analysis of hydraulic actuators.These three papers were selected for review to connect the valve required torque with actuator sizing and selection,finding practical approaches to optimize the actuator weight as well as develop a theoretical model to calculate the actuator thickness and dimensions for the 38”CL1500 ball valve in the Johan Sverdrup project.The proposed formulas and calculations used for sizing the 38”CL1500 ball valves were validated through a finite element analysis model.
基金Item Sponsored by Korea Science and Engineering Foundation(KOSEF)Grant Funded by Korea Government(MEST)(2010-0022521)
文摘It is difficult to obtain the desired strip shape using Sendzimir rolling mills because small diameter work rolls can be easily deformed by the roiling force. To control the strip shape effectively, it is important to understand the relationship between the behavior of the shape actuator and the variation of the strip shape. A numerical model based on the contact element method was proposed for the prediction of strip shape. In this numerical model, the re- lationships between the actuating forces, the roll deflections, the thickness profiles of the entry and exit sides, and the strip shape were considered. The proposed numerical model for strip shape prediction was evaluated by computer simulation and experiment with respect to various AS-U roll and first intermediate roll positions.
