PYRO-Accumulator: Rocket Motor Powered Hydraulic Power Source

Abstract This paper describes the PYRO-Accumulator, a piston accumulator which uses a solid propellant rocket motor instead of compressed gas. The rocket motor is used as a gas generator to pressurize hydraulic fluid inside the piston accumulator. PYRO-Accumulator is a self-contained, unpressurized dormant device, much like an airbag system for automobiles, which provides pressurized hydraulic fluid on demand. It is particularly suited for emergency single-use applications such as closing of subsea BOP shear rams, or applications requiring finite number of operating cycles. PYRO-Accumulator is a conventional piston accumulator that is retrofitted with a PYRO Kit in the space that would normally contain the nitrogen gas. Only minor cap modifications are required and which do not change the piston accumulator pressure vessel certification. Replacing the nitrogen gas with a PYRO Kit increases the accumulator usable fluid by more than 5X for the same working pressure resulting in significantly reduced weight and footprint. Additionally, the PYRO equipped accumulator requires essentially no maintenance and has a service life of more than 10 years, and offers quantifiably and scalable high reliability. Results from a pipe shearing demonstration are also provided.