（1）弄清设备的情况，要了解设备转轴的转速、轴径；设备制造精度及密封腔尺寸，设备本身的使用寿命以及设备在生产工艺中的地位等要做全面均衡的考虑。
(1) to understand the situation of the equipment, it is necessary to understand the rotating speed and diameter of the rotating shaft of the equipment, the manufacturing accuracy of the equipment and the dimension of the sealing cavity, the service life of the equipment itself and the position of the equipment in the production process.
（2）估算介质压力。泵的密封腔压力一般不是泵的出口压力，而是低于泵的出口压力。
(2) estimate the medium pressure. The pressure of the sealing chamber of the pump is generally not the outlet pressure of the pump, but lower than the outlet pressure of the pump.
（3）弄清密封介质情况。要了解密封介质的状态，是气态还是液态，介质是否含颗粒及颗粒状况；了解介质的性质、温度，以便合理选型及采取必要的冷却、冲洗、润滑措施。
(3) find out the sealing medium. It is necessary to know the state of the sealing medium, whether it is gaseous or liquid, whether the medium contains particles and particle state; know the nature and temperature of the medium, so as to reasonably select the type and take necessary cooling, flushing and lubricating measures.