In order to improve the transport efficiency of cement and reduce the waste of resources caused by bagged cement, most of the cement is transported by bulk cement tankers at present, because the cement tankers are transported and unloaded by pneumatic means, and the unloading speed and the residual rate of unloading are important indicators to assess the unloading efficiency of the cement tankers. It is very important to adopt correct methods to ensure that the cement in the tank is discharged as much as possible. Because the cement in the tank cannot be seen directly by the naked eye during the unloading process, some methods must be used to identify the unloading situation of cement. Here are some simple methods to determine whether the cement has been unloaded:

　　压力表检查法：散装水泥罐车在卸料时，罐内空气压力为1.8～2.4公斤/平方厘米，卸料快结束时，气压快速下降，如果压力表降到0～0.2公斤/平方厘米之间，则证明罐内水泥基本卸完。

　　Inspection method of pressure gauge: when unloading the bulk cement tanker, the air pressure in the tank is One point eight ~ Two point four Kg / cm2. At the end of unloading, the air pressure drops rapidly. If the pressure gauge drops to 0 ～ Zero point two Between kg / cm2, the cement in the tank is basically discharged.

　　卸料时间判别法：正常水泥罐卸料速度一般为每分种1～1.2吨，如果水泥装载重量为32吨，则一般需要半小时左右卸完，所以可以根据卸料吨位计算卸料时间，这样前25分钟操作人员比较轻松，没有必要长时间紧盯压力表或通过其它方法检查是否卸完。

　　Determination of unloading time: the unloading speed of normal cement tank is generally 1 ~ per minute One point two Tons, if the loading weight of cement is 32 tons, it usually takes about half an hour to unload, so the unloading time can be calculated according to the unloading tonnage, so that the operators in the first 25 minutes are relatively easy, there is no need to stare at the pressure gauge for a long time or check whether the unloading is completed by other methods.

　　空压机声音辨别法：正常卸料时空压机负载大，空压机工作时发出的声音比较沉闷，罐体卸料结束时，空压机负载变小，工作声音变得清脆。

　　Air compressor sound identification method: the load of the air compressor is large in normal unloading time and space, and the sound produced by the air compressor during operation is relatively dull. When the unloading of the tank is completed, the load of the air compressor becomes smaller and the working sound becomes crisp.

　　敲打罐体法：水泥卸料过程中，可以用手敲打罐体，如果声音没有回音，则证明罐体内水泥余料较多，还要卸一段时间;如果罐体有回音，证明罐体内水泥快卸完了。

　　Knock tank method: in the process of cement unloading, you can knock the tank with your hands. If there is no echo in the sound, it is proved that there is more cement surplus in the tank, and it will be unloaded for a period of time; if there is echo in the tank, it is proved that the cement in the tank is almost discharged.

　　卸料软管观察法：正常卸料时，卸料软管受流化水泥冲击，软管不断抖动，如果软管不再抖动，也可证明罐内水泥基本卸完。

　　Observation method of unloading hose: during normal unloading, the unloading hose is impacted by fluidized cement, and the hose keeps shaking. If the hose does not shake, it can also prove that the cement in the tank is basically discharged.

　　水泥接收塔顶扬灰辨别法：正常卸料时，水泥消耗的气量相对较少，“料多气少”，接收塔顶扬灰较少，卸料后期“料少气多”，接收塔顶扬灰增多。

　　Identification method of lifting ash on the top of cement receiving Tower: during normal unloading, the gas consumption of cement is relatively less, "more material and less gas", less lifting ash on the top of receiving tower, and "less material and more gas" at the later stage of unloading, more lifting ash on the top of receiving tower.