A tank truck with a heavy-duty DENVER-NASH liquid ring vacuum pump designed to vacuum load hazardous and non-hazardous liquids, sludge or slurry.
The function of a liquid-ring pump is similar to a rotary vane pump, with the difference being that the vanes are an integral part of the rotor and churn a rotating ring of liquid to form the compression-chamber seal. They are an inherently low-friction design, with the rotor being the only moving part and therefore acknowledge as the solutions to vacuum load hazardous liquids.
The truck can be configured to be a direct belt drive, or a hydraulic drive system. There are two different ways to mount the pump either directly on the truck with the vacuum drive powered by the truck motor, or on the trailer with an independent motor. Each application has different handling characteristics.
The earliest liquid-ring pumps date from 1903, when a patent was granted in Germany to Siemens-Schocket. US Patent 1,091,529, for liquid-ring vacuum pumps and compressors, was granted to Lewis H. Nash in 1914. They were manufactured by the Nash Engineering Company in Norwalk, CT.