Undersea projects requiring high-pressure pumps are hampered and costly if the pumps themselves have to be placed on the surface.
While surface pumps avoid corrosive action and pressure limits that can impact some sub-sea pumps operating in ocean environments, the use of hose required to bring the high-pressured pump action to the work area below the surface can impose extra costs exceeding $100,000, depending on the depth.
An underwater pump capable of high-pressure discharge can be mounted on a submersible remote operated vehicle to work on the sea floor, requiring only about 20 feet of hose and avoiding excessive pressure drop associated with long lengths of hose required with surface pumps.
Submersible pumps are extremely value for use with deep-sea oil rigs for such jobs as hydrostatic testing and blow-out preventer testing that can be done on the sea floor under real operating conditions. High-pressure submersible pumps are also used for pipeline lining/coating removal.
The demands of the undersea environment, however, requires a submersible pump built to withstand the extreme pressure of ocean depths, avoid corrosion in sea water yet still discharge high pressure.
An example of a pump solution for underwater work is Jetech’s Model UW-UH Sub-Sea line of triplex and quintuplex underwater pumps can provide up to 40,000-psi (2750 bar) discharge pressure, the only submersible positive displacement pump capable of such high-pressure discharge. They are made with all stainless-steel construction to tolerate sea water.
The design of the UW-UH pumps permits the crankcase of the pumps to be flooded by seawater to have zero differential pressure between the internal and external casing of the power-end. This will allow the underwater pumps to operate in the deepest depths of the ocean. These pumps also do not require oil or grease in the power end. Instead, they are engineered to operate using seawater for cooling and lubricating the bearings and other moving components.