M s industries offers piston pumps from 500 to 10,000 lpm capacity. These operate on the rotary plunger principle. The eccentrically rotating cam rigidly connected to the driving shaft, moves the piston to slide along the inner wall of the pump chamber effecting cyclical change in the pump space volume. The movement of the piston oscillates the integrally cast slide valve to and fro. Air streams into the hollow inner space of the slide valve which is permanently open to the suction port and gets displaced through the lateral aperture of the slide valve during the cyclical change in the pump space volume. Air thus displaced is sealed and swept away, only to get compressed and expelled through the outlet valve. Also available are vane pumps from 30 to 1000 lpm capacity. These operate on the principle of rotating vanes, which slide in a rotor with very high rpm. As the vanes sweeps around, the air from the systems is captured through the inlet port, compressed and thrown out to the exhaust valve. Advantages: all pumps are equipped with gas ballast to prevent [up to a certain limit] condensation of pumped water vapour, the limit of water vapour tolerance being 20-25 torr; compact construction with directly couple flanged on motor, which can start the pump even when cold, and against vacuum; reliability in continuous operation efficient pumping and easy maintenance; servicing is limited to checking the oil level and change of oil at regular intervals; easy partial dismantling facility for quick cleaning when heavily contaminated; built-in non-return lock prevents pumps from running in the wrong direction and from spontaneous backlash when closed down without ventilation; and cuts down recurring expenditure on expensive pump fluid by reduction in usage of oil to 1/10th of what is used by other such pumps.
