Sunday, September 4, 2016

Twin Screw Pumps As A Type Of Multiphase Pumping Technologies

By Laura Smith


Pumps are used for moving fluids, such as liquids, slurries, or gases. Three major groups of this are the displacement, direct lift, and gravity pumps. Positive displacement transfers fluid by trapping a fixed amount of it then displacing that amount into the discharge pipe.

Gravity pumps are referred to as hydraulic rams. These work by getting water from under grounds and raising it to higher places but in lower elevations. Multiphase pumping technologies have features and types namely the helicoaxial, progressive cavity, twin screw pumps, buffer tanks, and electric submersibles. Multiphase production benefits include smaller and simpler installation, production rate increase, and lower cost of equipment.

Helicoaxial is also referred to as centrifugal. This will work by converting the rotational kinetic energy into a hydrodynamic energy to transfer fluids. The electric motor releases a rotational energy, and the fluid that enters will be accelerated outwards by the impeller which is located near the rotating axis.

A twin screw is made up of two screws that pushes the fluid movement which is being pumped. Pumping conditions like having a high volume of gas or fluctuated inlet conditions are commonly used. Four mechanical seals are needed to seal these two shafts.

Progressive cavity is a type of positive displacement. It is used by progress of the sequence of small, fixed shape, and discrete cavities, as the rotor is being turned. This can also act as a motor or a mud motor when the solution is pushed through its interior. One application for this is well drilling.

An electric submersible has a motor which is sealed hermetically and that is close coupled to a pump. Its construction is been submerged to the pumped fluid. One advantage of submersibles is that it can prevent cavities, a common problem between the difference of fluid surface and pump. Submersibles pump the liquids to the surface, while the jets pull the liquids, so it is more efficient to use submersibles.

A buffer tank Cobourg ON is installed in the upstream of the suction nozzle in case of slug flows. This breaks the energy of liquid slugs, smoothens fluctuations in incoming flows, and act as sand traps. Pumps are mostly rated in its horsepower, outlet pressure of its head, inlet suction of its head, and flow rate. The head is simplified as the number of meters or feet that the pump raises or lowers the column of water of atmospheric pressure.

Stainless steel and other materials such as cast iron are mostly used for pump production. Materials depend on how it is going to be used. For pharma application of water industries, they use stainless steel instead of cast iron because it gives better outcome due to its high temperature.

So by the name itself, multiphase have many variations of services and conditions like changing composition of liquid processes, temperature variations, operating high and low pressures, and exposure to abrasive or erosive media. So the challenge for this is to look for appropriate arrangement of mechanical seal and support system to ensure effectiveness and also to ensure quality as well.




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