Working Principle
The working principle of the compressed air vacuum pump is based on an impeller mounted eccentrically within the pump casing. As the impeller rotates, centrifugal force causes the water inside the casing to form a rotating liquid ring against the inner wall. A sealed chamber is created between the liquid ring and the impeller hub; during the first half-revolution of the impeller, this chamber expands-causing the pressure to drop and draw in gas-while during the second half-revolution, the chamber contracts-causing the pressure to rise and discharge the gas. Each full rotation of the impeller completes one cycle of gas intake and discharge, thereby achieving continuous suction or compression. Heat is generated during operation, and a portion of the water is consumed; therefore, a continuous supply of water is required for cooling and replenishment. The pump is typically equipped with a gas-liquid separator to separate the gas-water mixture; the gas is discharged, while the water-after cooling-can be recirculated or replenished with fresh cold water to maintain the optimal operating temperature. The end cover features a disc fitted with rubber ball valves; these valves facilitate premature gas discharge-occurring as soon as the gas pressure between the impeller blades reaches the discharge pressure-thereby reducing power consumption.
Structural Components
The compressed air liquid-ring vacuum pump consists of several key components: the pump casing, two end covers, the impeller, and the shaft. The intake and exhaust pipes connect to the pump chamber via suction and discharge ports located on the discs mounted within the end covers. The clearance between the impeller and the end cover discs significantly influences the pump's performance; this clearance is adjusted using various methods, such as positioning the impeller via a shaft sleeve (for models SK-1.5/3/6), a back nut (for models SK-12/20/30), or through an interference fit (for models SK-42 and above). The pump utilizes a mechanical seal for shaft sealing; when a mechanical seal is employed, it is installed within the stuffing box cavity, replacing the traditional packing gland with a mechanical seal gland. The bearings are secured to the shaft by means of a round nut. The discs located within the end covers feature the suction and discharge ports as well as the rubber ball valves; the function of these rubber ball valves is to initiate premature gas discharge-specifically when the gas pressure between the impeller blades reaches the discharge pressure-thereby minimizing power consumption.
