The valve is the main component of the safety loop. Based on application, fluid composition and process requirements different types of valves may be suitable: Gate Valve, Ball Valve, Axial Valve. ATV HIPPS is able to choose the best option within ATV brand wide product basket or with any valve supplier based on customer’s preference.
The actuator is an important component of the safety loop. The most suitable actuation for HIPPS are Hydraulic and Pneumatic actuation based on available power supply. Self-acting actuation is an option as well when no power supply is available. Electric actuation is less common. ATV HIPPS can supply actuators from the market or its own actuators.
The logic solver is a very important component of the safety loop. Programmable or Solid State Logic Solvers are available based on SRS and Customer SIL goals. SIL 3 or 4 equipment is available in the market based on customers’ requirement and preference. An additional logic solver-free solution is available, using traditional mechanical HIPPS systems.
The pressure transmitters are the most common and suitable initiators of the safety loop. A pressure transmitter is an electronic instrument sensing the process fluid pressure and generating a 4-20mA signal to the logic solver, according to the calibration range. The recommended configuration is 2oo3.
Partial Stroke Device
The partial stroke device is a must in order to increase and keep required SIL levels. A certain number of partial stroke tests per year could be necessary to comply with SIL requirements. It depends on the reliability data of the final element components and the installation architecture. Different technical solutions are available.
The interlocking manifold allows safer operation of initiators. The interlocking manifold allows the system to isolate and vent the lines of only one initiator at a time, via a predetermined sequence in order to avoid spurious trips or problems due to misoperation. Special attention is required for selections based on process fluid composition.
The skid is a carbon steel or stainless steel structure of various dimensions that has to accommodate the components. It has to be designed according to API, ASTM, ANST standards and customer specific requirements.
Hydraulic Power Units
Hydraulic power units are normally mounted on the skid close to HIPPS valves. Accumulators for emergency strokes are installed on the valves or on the skid.
Choke valves need to control the flow on top of the wellhead. Choke valves are normally located close to HIPPS. A good practice would require a combined evaluation of HIPPS and Chokes in order to optimize process and sizing of the systems. Choke valves are available in single stage version for standard applications or multistage solution for more critical applications.
There are additional components that may be part of a skid mounted HIPPS, such as: Double Block and Bleed Valves, piping spools, vent system, drain system, etc.