Ｄ、限位器D, limiting device限位器为一个底部带限位板和流通通道的短节，接在定子的尾部，其作用是施工作业时给转子限位以防止下入过头而失去作用和杆柱脱落时防止杆柱掉入井底。The limiting device is a short section with bottom limit plate and distribution channel, which is connected to the tail of the stator. Its function is to limit the rotor to the rotor during ctruction1, so as to prevent it from falling into the overhead and lose its function and prevent the rod from falling into the bottom when the rod string falls off.



Ｅ、抽油杆扶正器E, sucker rod centralizer抽油杆扶正器由心轴和扶正筒组成，它接在两根抽油杆之间，被卡在两个抽油杆接箍之间。心轴也就是一要极短的抽油杆短节。扶正筒是一个内孔比心轴大１ＭＭ左右的空心塑料筒，外部有四个略比油管内径小的扶正翼，采取浇注成型。扶正筒可以围绕心轴转动，防止抽油杆旋转时与内壁接触而磨蚀油管，又可以让流体通过。The sucker rod centralizer is composed of the heart shaft and the upright cylinder, which is connected between the two sucker rods and is stuck between the two sucker rod hoops. The axis of the heart is also an extremely short rod short section. The centering cylinder is a hollow plastic tube inner hole Bixin shaft around 1MM, external four slightly ***aller than the diameter of the tubing centralizer wing, adopt casting. The centralizer can revolve around the axis to prevent the sucker rod from touching the inner wall when it rotates, and it can also let the fluid pass through.

　单螺杆泵有以下优点：

　　1)因为泵内的回转部件惯性力较低，故可使用很高的转速;

　　2)结构坚实，安装***容易;

　　3)单螺杆泵的压力和流量范围宽阔。压力约在3.4-340千克力/cm2，流量可达18600cm3/分;

　　4)单螺杆泵的吸入性能好，具有自吸能力;

　　5)与其它回转泵相比，对进入的气体和污物不太敏感;

　　6)流量均匀连续，振动小，噪音低;

　　7)单螺杆泵的运送液体的种类和粘度范围宽广。

　　单螺杆泵的缺点是，螺杆的加工和装配要求较高;泵的性能对液体的粘度变化比较敏感。