1. What is the function of vacuum pump? What kinds of vacuum pumps are commonly used in refineries?
A vacuum pump is designed to cause a vacuum in the equipment or container, so that it can work under the condition of lower atmospheric pressure or high vacuum. The vacuum pumps commonly used in refineries include steam jet vacuum pumps, water ring vacuum pumps and reciprocating vacuum pumps.
2. What is the working principle of steam jet vacuum pump?
It consists of a nozzle, a mixing chamber, an expansion chamber and a pressure outlet. In the work, the water vapor at high speed (1200-1500m/s) from the spray nozzle into the mixing chamber, then produce certain negative pressure in the nozzle, then pumped gas from the gas inlet into the mixing chamber, mixed with water vapor, and get some energy from water vapor. When the mixture flows into the diffuser chamber, the flow velocity decreases along the axis, and the pressure gradually increases along the axis until it is larger than the external atmospheric pressure. As a result of continuous work, the gas in the equipment is constantly pulled out, so a vacuum (negative pressure) state is brought into the equipment.
3. What are the features of steam jet vacuum pump?
Steam jet vacuum pump with high speed water vapor to be pumped out of the gas entrainment, so it has the characteristics of large pumping quantity, high vacuum, simple manufacture, installation and maintenance are more convenient, currently using the vacuum pump vacuum distillation unit of the refinery for steam jet vacuum pump.
4. What is the structure of the water ring vacuum pump? What is the working principle of the water ring vacuum pump?
Water ring vacuum pump consists of pump shell, impeller, water ring, suction chamber, discharge chamber, exhaust hole and so on.
Impeller eccentric installed in the pump shell, impeller installed on a lot of blades. Before starting the pump, the pump shell to hold about half of the water, start the pump when the impeller rotates clockwise, the water is formed and the impeller drives the water ring out of the center, then the pump blade space is divided into many different sizes due to the piston chamber, the water right, the impeller chamber pressure gradually expanded. Reduced, was pumping gas from the inlet into the suction chamber; the impeller left chamber gradually reduced, the pressure increases, the gas from the discharge chamber is discharged through the exhaust port. In this way, due to the constant rotation of the impeller, the gas will continue to inhale and exhaust, the vacuum can reach 67-80KPa.