Using Double-acting Hydraulic Actuators for Weight Reduction in the Offshore Industry

Abstract

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.

Keywords

Valve automation / Hydraulic actuator / Quarter turn movement / Single acting / Double acting / Offshore Industry