比如此次大泵为三级串联为例，通常第三级泵必须安装变频器，第一级最好也装，第二级并不需要装变频器，在使用的时候: 先是开第一级的泵，让浆液将所有的管路及泵充满，转速逐渐增加，然后逐渐提高转速至额定转速，然后打开第二级泵，然后在打开第三级泵，由于第三级泵有变频器，所以通过调整第三级泵的转速来调整整个系统的扬程及流量。关闭的过程反之即可！通过减少变频器的数量可以大大节约投资成本！

4. The control procedures and methods for multi-stage pump:

Let’s take the three-stage series pump as an example. Usually the third-stage pump must be equipped with a transducer, and the first-stage pump had better have one too while it is unnecessary to fix one for the second-stage pump. When you use the pump, firstly start the first-stage pump to let all pipelines and the pump be filled with slurry, then gradually increase its revolution to rated speed. Start the second-stage pump and then the third-stage pump. Since the third-stage pump has a transducer, you can adjust system lift and flow by changing the revolution of the third-stage pump. In reverse order, the pumps can be closed. As a result, the investment costs will be greatly reduced by decreasing the quantity of transducers.

5. 关于泵的控制柜，经我公司开会研讨认为，在现场如果安装变频器的话完全可以通过变频器实现泵的开停及调速，如果像上面第四个所说，只给第一和三级泵安装变频器，那么第二级是可以单独安装控制柜来控制开关的！所以此次我公司不单独提供控制柜，如果只需要几台控制泵开关的变频器，我公司将会免费提供！厂家为中国国产品牌！

5. As for control cabinet for the pump, after discussion, we think if we install transducers at site, we can control the pump and its speed by operating transducers. If we only install transducers for the first and third-stage pumps as said in part 4, we can install a separate control cabinet for the second-stage pump to control its start and stop. We will not supply control cabinet this time, but our company can supply several transducers for controlling pumps free of charge. The transducers we supply are from a Chinese home-made brand.

6. 如果商务和技术在技术服务及培训上有分歧，那么以标书中服务时间长的为准！

6. If there are any discrepancies in technical services and training on commercial and technical terms, the longer service period in the bidding document shall prevail.

7. 关于类似的高扬程的泵的业绩介绍，请见附件！

7. Please see attachment for the similar performance lists for high-lift pumps.