The limit pressure of double-stage liquid-ring vacuum pump is 3300 Pa, and the ideal working pressure range is 20 Kpa-100 Kpa. When the inlet pressure is lower than 20 Kpa, the pumping capacity decreases rapidly, and the efficiency of single-stage water-ring vacuum pump is very low. Two-stage liquid ring vacuum pump design two-stage compression process, pumping speed is stable in a higher vacuum range, or maintain a higher vacuum in a large range of pumping rate. In higher vacuum working condition, the efficiency is increased by 35% to 40% compared with single stage water ring pump, and the energy consumption is reduced accordingly.
Two-stage Liquid Ring Vacuum Pump Working Principle
The working principle of suction and exhaust of two-stage liquid ring vacuum pump is the same as that of single-stage liquid ring vacuum pump. When the impeller rotates, an eccentric water ring is formed on the inner wall of the chamber and filled with water between the blades. With the impeller rotating, periodic reciprocating motion is continuously made between the blades. The volume of the middle of the blade is changed, and the process of suction, compression and exhaust is completed with the corresponding cooperation of the fixed suction and exhaust ports. The second stage is to reduce the exhaust pressure of the first stage and improve the vacuum of the first stage.
Two-stage Liquid Ring Vacuum Pump Characteristics
1. Limit pressure can reach 2 Kpa, entrance working pressure range is 5 Kpa-20 Kpa.
2.200-7500m3/h of various specifications to meet the needs of various processes
3. Selection of stainless steel, duplex steel, titanium, Harrington alloy and other materials
4. Reliable ways of impeller locking and loosening prevention
5. Mechanical seals at both ends and selection of various flushing schemes
6. Standard anti-cavitation device
7. Reliable performance, high efficiency and energy saving
8. Precision castings, imported bearings, high-standard accessories
Two-stage Liquid Ring Vacuum Pump Typical Application
1. Vacuum evaporation/distillation process with evaporator
The vacuum system of evaporator generally requires that the inlet vacuum should be between 6 and 10 Kpa with a larger pumping capacity. The single stage water ring vacuum pump has a rather weak pumping capacity in this section, while the double stage water ring vacuum pump is chosen to give full play to the maximum pumping capacity at this time. Under the same energy consumption, the efficiency is increased by more than 30%.
2. Atmospheric and Vacuum Equipment on Top of Fine Chemical Tower
Atmospheric and vacuum distillation vacuum devices also require a higher pumping capacity at a lower vacuum. Even if a single stage water ring vacuum pump with a first stage atmospheric ejector is selected, the pumping rate at the suction pressure of 5 kPa-6 Kpa is only 65-70% of the maximum of the pump. Therefore, bipolar water ring vacuum pump is an ideal choice for atmospheric and vacuum distillation vacuum device.
3. Condenser Vacuum Extraction Device of Power Plant Steam Turbine
At present, 2BE1 series water ring vacuum pumps are mainly used to vacuum condensers in power plants. The vacuum of air ejector is increased, but the efficiency of air extraction is reduced and the energy consumption is high. The maximum air volume of 2BE1S series double-stage water ring pumps can reach 7500m3/h. High quality heat exchangers and instrument valves are selected to meet the requirements of high reliability.
3. Roots Unit with Roots Vacuum Pump
The key to ensure the long-term stable operation of Roots vacuum unit is to select two-stage water ring pump with high quality control system. At present, the 2BE1 and 2BV series water-ring vacuum pumps are generally used as the front-stage pumps in the water-ring Roots units. The Roots pumps are overloaded and heated in operation, and their service life is short. With 2BE1S series double-stage water ring pumps, the pumping capacity is greater under lower inlet pressure, that is, to reduce the exhaust pressure of Roots pump, so that Roots pump always operates within the allowable range of pressure difference, no overload heating, to ensure the safe and reliable operation of the unit.
Two-stage Liquid Ring Vacuum Pump and Single-stage Liquid Ring Pump Comparison and Selection
Two-stage liquid-ring vacuum pump and single-stage liquid-ring vacuum pump are designed and developed for different operating conditions. From the above curves, it can be seen that the pumping speed of single-stage liquid ring vacuum pump decreases seriously in the range of high vacuum (less than 2000 Pa), even less than 30% of the maximum pumping speed at 5000-1000Pa. Under this condition, the efficiency is very low and the power consumption is high. However, under the condition of rough vacuum, it shows the advantage of large pumping capacity. The two-stage liquid ring vacuum pump can achieve a higher pumping speed in a higher vacuum range, or maintain a higher vacuum in a larger pumping rate range. In higher vacuum working condition, the efficiency is increased by 35% to 40% compared with single stage liquid ring pump, and the energy consumption is reduced accordingly. Therefore, the appropriate vacuum pump should be selected according to the use conditions in order to reduce energy consumption and economic operation.
Two-stage liquid ring vacuum pump technical parameters
|Model||Suction capacity||Ultimate vacuum||Power||speed||Water supply||Inlet/outlet diam||Water inlet|