DLRC系列双级液环真空泵利用泵壳和叶轮的不同心地安装的结构，在叶轮作旋转时,形成与叶轮成偏心的水环，随着叶轮的旋转，在叶片之间不断地作周期性的往复运动。改变叶片中间的容积，在固定的吸气口和排气口的相应配合下，完成吸气、压缩和排气作用，而双级的作用就是第一级排气口排出的气体被第二级吸气口吸入，然後经过第二级的压缩排出，第二级的作用是减少第一级排气压强，以提高第一级吸入极限真空度。做成同轴相串联的两级泵，两级之间的通气道由中间盆和连接管配成，因此结构比较紧凑，回转部分由一根轴和两级叶轮组成，固定部分由进出气机座，两个泵环和配气盘及轴承支架组成。

         The two-stage and single-stage water ring vacuum pumps are designed and developed for different operating conditions. The single-stage water ring vacuum pump has a significant reduction in pumping speed within a higher vacuum range (less than 20,000 Pa), and even at 5,000 to 10,000 Pa, its pumping speed is less than 30% of the maximum pumping speed. In this condition, the efficiency is extremely low and the power consumption is high. However, the two-stage water ring vacuum pump can achieve a greater pumping speed within a higher vacuum range, or maintain a higher vacuum level within a wide pumping rate range. In a higher vacuum operating state, its efficiency is 35% to 40% higher than that of the single-stage water ring pump, and the energy consumption is also reduced accordingly. When used as the pre-stage pump of a Roots vacuum pump, its effect is particularly ideal.

　　双级和单级水环真空泵是针对不同的使用工况设计开发的。单级水环真空泵在较高真空度(小于20000Pa)范围内，抽速衰减严重，在5000至10000Pa时甚至不足最大抽速的30%，在此工况下效率极低，功耗较高。而双级水环真空泵，在较高的真空度范围内能获得更大的抽速，或者在很大的抽气速率范围内维持较高的真空度。在较高真空工作状态时效率较单级水环泵提高35%至40%，能耗也相应降低。把它作为罗茨真空泵的前级泵使用效果尤为理想。

DLRC 双级液环真空泵的性能参数

Note: The performance parameters listed in the above table were obtained under the conditions of saturated air at 20℃ as the intake medium, water as the working fluid, and a temperature of 15℃, with an exhaust pressure of 1013 mbar.

注：上表中所列性能参数是在吸入介质为20℃的饱和空气，工做液为水且温度为15℃，排气压力为1013mbar的状态下得到的。