Facility operators in the oil and gas industry have raised concerns on how to solve their top failure modes: extremely short or non-existent dry run pump time limits and unacceptable levels of cavitation when pumping extremely light liquids with high vapor pressures.
Pump cavitation and dry run related failures cost companies millions of dollars annually, including replacement costs for damaged equipment and lost sales due to poor performance. With an improving economy and anticipated fuel production increase, sales of fluid-handling pumps are forecast to rise 5.5% annually to $84 billion in 2018. Given this proliferation, the historical pattern suggests that costs associated with repairs or replacements also will increase dramatically.
Learn how Parker's innovation in pump technology can reduce your operational downtime, decrease operating costs, and improve performance. Download our white paper now.
Dry running occurs when a pump operates without sufficient lubricating liquid around the pumping element. This can be caused by either widespread vapor formation, also known as cavitation, inside the pump or absence of pumping fluid altogether. These adverse conditions can lead to dangerously unstable pressure, flow, or overheating which may cause the pumping element to seize or break.
When cavitation occurs, vapor bubbles form and expand in the pumping liquid on the suction side of the pump before reaching the higher-pressure discharge side of the pump and violently collapsing near the surface of the pumping element. This triggers shock waves inside the pump which cause significant damage to the pumping element. If left untreated, cavitation will destroy the pumping element and other components over time, drastically shortening the pump’s life.
Cavitation may also cause excessive vibration leading to premature seal and/or bearing failure, in addition to creating an immediate increase in power consumption and a decrease in flow and pressure output.
Cavitation itself may also be so widespread that it creates a dry run situation inside the pump due to excessive vapor formation. Pumps most often rely on the pumping fluid itself to lubricate the bearing surfaces of the pumping element – if a pump is operated without this fluid, the low to non-existent lubrication at these bearing surfaces will cause excess heat generation, increased wear, and potentially even failure of the pump if the pumping element seizes or breaks. The life of a pump subjected to dry run will be significantly reduced or, in the worst case, brought to an untimely end.
Human error as the main cause of dry running
Whereas cavitation is a common cause of pump degradation and failure related to the physics involved in the pumping operation, dry running, on the other hand, is usually related to how pumps are actively operated by end users. The most immediate cause of dry running is usually human error. Companies rely on operators to monitor their pumps, but problems occur in cases where operators unintentionally leave pumps running after the pumping operation is complete.
Despite an operator’s best efforts, harmful events still may occur from:
malfunctioning monitoring systems;
improper use of even well-designed control equipment;
pumps running overtime after the pumping operation is complete;
Solving the dry running challenge
Our engineers were up for the challenge and developed the next generation solution of fluid transfer systems. The new technology combines advanced engineering and manufacturing capabilities to deliver a rugged solution for stationary, mobile, and high vapor-pressure ﬂuid applications.
The solution offers customers efficiency improvements as well as increases their uptime, which ultimately translates into revenue to the bottom line.
“What separates our solution from our competitors is, our technology is automated and integrated into the pump design. You don’t need to worry about pumps stopping and starting every 20 – 30 seconds, they will dry run continuously.”
James Chu, PE, chief engineer, Corporate Technology Ventures, Parker Hannifin
Learn how this innovation in pump technology can reduce your operational downtime, decrease operating costs, and improve performance. Download our white paper now.
Article contributed by Sara Weichman, business development manager, Fluid Transfer Solutions, Parker Hannifin
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