A riser board allows a computer motherboard to add additional expansion cards. Riser boards for desktop computers were available with NLX, LPX and some ATX motherboards. LPX motherboards featured a riser slot, while NLX motherboards were plugged into a riserboard. In December 1999, Intel released an ATX motherboard with a riserboard. Although the ATX riser board could support two or three PCI cards at a time, it never supported AGP. Buy Second hand Server Riser card online in India at Sureworks.store, Shop all kind of Refurbished IT spare parts online in Sureworks.store

Riser boards are not used in modern desktop computers. They are mostly found on ATX motherboards with expansion slots. Riser boards are still used in many routers and servers. Below is an image of a 4-slot riserboard that was used with early Compaq computers. It plugs into the motherboard, giving the computer the ability of adding four expansion cards.

Subsea risers, which are designed for vertical transport, use conduits to transport materials from the seafloor to production or drilling facilities. Risers can be used as import/export or production vehicles.

  • Multiple Riser Configurations
  • Multiple Riser Configurations

Like flowlines or pipelines, risers transport hydrocarbons as well as production materials like control fluids and gas lift. Risers are usually insulated to withstand the seafloor temperatures. They can either be rigid or flexible.

Types Of Risers

There are many types of risers available, including pull tube risers and attached risers as well as steel catenary risers.

Attached risers were the first type of riser developed. They can be deployed on fixed platforms or compliant towers, as well as concrete gravity structures. Attached risers connect the seabed to the production facilities above by being clamped to the sides of fixed facilities. Usually, sections are fabricated. The section closest to seafloor is connected with an export pipeline or flowline and clamped to its side. Next, the sections that rise higher up the facility’s side are joined to the top riser section.

Pull tube risers can also be used on fixed structures. These are flowlines or pipelines that are threaded up to the center of the facility. A pull tube that is larger than the riser’s diameter is used for pull tube risers. A wire rope is then attached to the pipeline or flowline at the seafloor. The pull tube is pulled to the topsides of the line, and the pipe is brought along.

Steel catenary risers also use the curve theory to build on the catenary equation, which has been instrumental in creating bridges around the globe. Steel catenary risers can be used to connect the seafloor with production facilities higher up, and also to connect two floating production platforms. They are found on TLPs, spars, FPSOs, and fixed structures as well compliant towers and gravity structure. This curved riser is able to withstand some movement, but excessive movement can lead to problems.

Top-Tensioned Risers

Top-tensioned risers can be used on spars and TLPs. They are completely vertical riser systems that terminate below the facility. These floating facilities can move laterally with wind and waves, even though they are moored. Vertical displacement can occur between the facility’s connection point and the top of the rigid risers, which are also fixed to seafloor. This issue can be solved by two methods. The top-tensioning riser can have a motion compensator that maintains constant tension by contracting and expanding with the facility’s movements. To keep the riser afloat, buoyancy cans can be placed around its outside. The facility is then connected to the top of the rigid vertical, top-tensioned riser by flexible pipe. This is more flexible and can accommodate the facility’s movements.

The riser towers, first used offshore Angola by Total’s Girassol Project, were constructed to raise the risers to the required height to reach the FPSO. This riser design is ideal for ultra-deepwater environments. It includes a tower made of steel that extends almost to the surface and is topped by a huge buoyancy tank. The tower’s risers extend from the seafloor to its top and include the buoyancy tanks. The risers are kept in place by the buoyancy of the tanks. The flexible risers are connected to the vertical risers, and finally to the facility.

  • Hybrid Riser System
  • Hybrid Riser System

Flexible risers are a hybrid that can be used in a variety of situations. They can withstand vertical and horizontal movement making them great for floating facilities. Flexible pipes were originally designed to connect production equipment to export risers and production risers aboard floating facilities. However, they are now used as primary risers. Flexible risers come in many configurations. There is the lazy S and steep S, which use anchored buoyancy module, and the lazy wave and steep wave that include buoyancy modules.

Production and import/export risers transport hydrocarbons and production materials during development. Drilling risers transfer drilling fluids to the surface. Drilling risers are temporarily connected to the subsea BOP stack and the rig at top to connect the wellbore to surface. This is to prevent drilling fluids from leaking into the water.