API/ANSI/ISO Process Pump

Tough pumping job requires sturdy pumps
API pumps meet Standard 610 for General Refinery Service as set by the American Petroleum Institute (API). This U.S. trade association for the oil and natural gas industries develops standards for petroleum and petrochemical equipment. Unlike the ANSI standards, which are dimensional, API Standard 610 focus on the pump’s construction and design, particularly as they pertain to the pump’s ability to handle high temperatures, pressures and emissions. API pumps are the choice for more aggressive applications in the oil refinery industry. Their casings, bearing houses, mounting feet and back cover arrangement are all designed for maximum efficiency and reliability in oil refinery applications, as well as controlling emissions and safely handling fluids that can cause environmental damage.
ANSI  B73.1 process pumps are horizontal, end suction, single stage centrifugal pumps with an overhung impeller and back pull out. Their defining feature, however, is their interchangeability across manufacturers and brands. ANSI pumps are most often used to transfer thin fluids such as water, alcohols, and other less aggressive fluids. They can move fluids with or without solids depending on the impeller type. They can also be made with high hardness materials and alloys for use in more demanding and corrosive environments. ANSI pumps have been a staple in the chemical industry for decades and commonly found in general manufacturing, and some typical process plants.
The older ISO 2858 focussed on external dimensions and mounting details, cover the same type of industrial pumps as ANSI B73.1 features but still  with different construction dimensionally . Many of the ISO certified products coming out of Europe, and Germany specifically, have impressive new energy efficient technologies that may not be available in their ANSI counterparts. There is a reason that German designed products are known for their quality, efficiency, and long service lives.