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Condensate pump at a steel mill

Hydra-Cell pumps perform well with hot liquids, even with a continuous duty cycle – rewarding the care that should always be taken with product selection and system design. This application in a Missouri steel mill is an example of good practice. Considerations include pump component compatibility, suction conditions to avoid cavitation, and maintaining proper lubrication in the hydraulic end.

The mill installed a belt-driven Hydra-Cell H-25 pump to act as a ‘de-superheat pump’ handling hot condensate at 200°F (93°C). The application required a 24 hour/day duty cycle. Brass was chosen as the pump head material, as it runs cooler than cast iron or stainless steel. The combination of high temperature and continuous duty also made it advisable to install a heat exchanger and recirculation pump as a loop into the hydraulic end of the pump.

This convection coil style heat exchanger was mounted approximately 12 inches (30 cm) from the pump. A small gear pump provides the re-circulation. The motor oil exits the pump from the oil drain at 100°F (38°C) and returns to the oil fill port at 95°F (35°C). Only an additional 1 litre of oil is required to fill the heat-exchanger and additional plumbing. The installation is in an ambient environment of 70°F (21°C).

One of the important issues in hot applications is adequate suction pressure to avoid cavitation, or having the fluid ‘boil’ within the pump. The process medium must remain ‘liquid’ at all times. For this application, it was found that a suction pressure of 32 psi (2.2 bar) resulted in smooth pump performance. Reducing the suction pressure to just 23 psi (1.6 bar) caused the system to cavitate violently. Hot liquids standing by themselves may not boil. Moving these hot fluids is made difficult due to partial vacuums.

Continuity is essential on this application, so the steel mill carries an identical spare pump on site, to be installed when service is required on the operational pump. There was no immediate need. Three months after installation the mill was able to report three months of continuous trouble-free operation.

Model: H25 in Brass

Flow: 12 gpm (45 lpm)

RPM: 600 - Belt Drive

Pressure: 650 psi (45 bar)

Liquids:

Hot Condensate,