ESD and Components
Stream-Flo’s Crown Hydraulic Self-Contained, Spring-Fail Closed Emergency Shutdown (ESD) System is used for the automatic closing of gate valves on wellheads and flow lines under emergency conditions. The system consists of a hydraulic actuator, a manual hydraulic pump and control assembly, and a reverse-acting gate valve. The system can be tripped by several means, the most common means by a pressure pilot which trips the system when it senses pressure fluctuations outside of the specified control range.
Stream-Flo’s Self-Contained Hydraulic Surface Safety Valve Actuation Systems require no flowline pressure, compressed air, gases nor electricity for power and instead utilizes its own clean, contaminant free, closed-loop hydraulics to power and control the actuation system. As a result, these systems are defined as “self-contained” making them ideal for use in remote applications or in applications where a power source for an actuation system is not available, unreliable or is very costly to produce and/or maintain.
The system operates totally independent of the produced fluids using only its own clean hydraulic fluid in a closed-loop, bubble tight circuit as its operating medium. Risk of contamination of the actuator and trip control circuits is eliminated ensuring long term system reliability and durability.
ESD Design Features – Actuator
The actuator is spring-return, hydraulically opened for use on reverse-acting gate valves. The valve is opened and closed by the application and release of hydraulic pressure. Modular design allows the actuator to be changed independently of the gate valve and bonnet assembly thus providing ease of service or replacement.
ESD Design Features – Assembly
Built-in gate stops, both upper and lower are incorporated in the bonnet. This enables the valve and bonnet to be completely assembled and stroke set independent of the actuator. Metal-to-metal stem back seat provides a means of sealing to isolate the stem-packing cavity in the event of a stem packing failure in addition to providing an upper travel stop for the gate.
ESD Design Features – Pump Control Unit
This unit consists of a manual pump, a pressure-reducing valve with a built-in accumulator, and a manual override valve. This unit is designed for ease of removal and modular component replacement. The check valve in the pump assembly provides leak-tight checking of the high-pressure hydraulic fluid back flow, ensuring reliable performance and low maintenance services. Large suction filter in the pump provides high flow and extended trouble-free service life.
