Classic pumps are exact dimension replacements for your original pumps. vacuum pumps from 20 CFM to 23,000 CFM vacuum pumps to 29+" HgV vacuum pumps designed to operate safely, cleanly and continuously in wet environments. require minimal care - known for extremely low maintenance. provide years of dependable service and quality liquid ring vacuum pumps due to fewer, generously proportioned parts. reduce power and operating costs of liquid ring vacuum pumps, handling higher capacities with less energy/power. nash_elmo is the inventor of the liquid ring principle of operation