In order to improve the transportation efficiency of cement and reduce the waste of resources caused by bagged cement, at present, the vast majority of cement is transported by bulk cement tanker. Because the cement tanker adopts pneumatic transportation for unloading, the unloading speed and unloading residual rate are important indicators to assess the unloading efficiency of cement tanker. It is very important to adopt correct methods to ensure that the cement in the tank is discharged as much as possible. Since the cement in the tank cannot be seen visually during unloading, some methods are needed to identify the cement unloading. Here are some simple methods to judge whether the cement is discharged or not:

1.壓力表檢查法，散裝水泥罐車在卸料時，罐內空氣壓力為1.8～2.4公斤/平方厘米，卸料快結束時，氣壓快速下降，如果壓力表降到0～0.2公斤/平方厘米之間，則證明罐內水泥基本卸完。

1. Pressure gauge inspection method: when the bulk cement tank truck is unloading, the air pressure in the tank is 1.8 ~ 2.4 kg / cm2. When the unloading is almost over, the air pressure drops rapidly. If the pressure gauge drops to between 0 ~ 0.2 kg / cm2, it proves that the cement in the tank is basically unloaded.

2.卸料時間判別法，正常水泥罐卸料速度一般為每分種1～1.2噸，如果水泥裝載重量為32噸，則一般需要半小時左右卸完，所以可以根據卸料噸位計算卸料時間，這樣前25分鐘操作人員比較輕松，沒有必要長時間緊盯壓力表或通過其它方法檢查是否卸完。

2. Judgment method of unloading time: the unloading speed of normal cement tank is generally 1 ~ 1.2 tons per minute. If the loading weight of cement is 32 tons, it usually takes about half an hour to complete the unloading. Therefore, the unloading time can be calculated according to the unloading tonnage. In this way, the operator is easier in the first 25 minutes. It is not necessary to keep a close eye on the pressure gauge for a long time or check whether the unloading is completed by other methods.

3.空壓機聲音辨別法，正常卸料時空壓機負載大，空壓機工作時發出的聲音比較沉悶，罐體卸料結束時，空壓機負載變小，工作聲音變得清脆。

3. Air compressor sound discrimination method: during normal unloading, the load of the air compressor is large, and the sound generated during the operation of the air compressor is relatively dull. At the end of tank unloading, the load of the air compressor becomes smaller and the working sound becomes crisp.

4.敲打罐體法，水泥卸料過程中，可以用手敲打罐體，如果聲音沒有回音，則證明罐體內水泥余料較多，還要卸一段時間;如果罐體有回音，證明罐體內水泥快卸完了。

4. Knock on the tank. During the cement unloading process, you can knock on the tank by hand. If there is no echo, it proves that there is a lot of cement residue in the tank and it will take some time to unload; If the tank has an echo, it proves that the cement in the tank is almost discharged.

5.卸料軟管觀察法，正常卸料時，卸料軟管受流化水泥沖擊，軟管不斷抖動，如果軟管不再抖動，也可證明罐內水泥基本卸完。

5. Unloading hose observation method: during normal unloading, the unloading hose is impacted by fluidized cement and the hose continues to shake. If the hose no longer shakes, it can also prove that the cement in the tank is basically unloaded.

6.水泥接收塔頂揚灰辨別法，正常卸料時，水泥消耗的氣量相對較少，“料多氣少”，接收塔頂揚灰較少，卸料后期“料少氣多”，接收塔頂揚灰增多。

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