In real life, the tragedy caused by the explosion of a bulk cement tanker is not an exception. When an explosion occurs, the operator will be “knocked away” by the shock wave or injured by the cover, causing serious casualties; the explosion will also cause great harm to the surrounding environment and people. Therefore, cement tanker drivers need to understand the causes of accidents in order to take precautions.
Causal Analysis of Bulk Cement Tank Truck Accidents:
Since the country has vigorously curbed overloaded transportation, many manufacturers have taken light weight as the main criterion for measuring the performance of vehicle products. In order to achieve light weight, some manufacturers use plates that do not meet the national standard thickness and strength to make bulk cement tankers, so as to reduce the weight of the tanker itself, but the compressive performance of the tank body has not been improved, and the compressive safety factor has become more and more smaller. When producing cement tankers, some manufacturers did not conduct strength tests on the tank bodies of the tankers in accordance with the requirements of “Technical Conditions and Performance Test Methods for Bulk Cement Tankers”.
Factors that reduce the safety of bulk cement tankers
- The tank body is scratched due to the use of lifting tongs during the transfer and production of the tank plate;
- When grinding or cutting off the welding slag and welding tumor on the tank, if the tank plate is worn or cut, the plate will become thinner;
- During the welding process of the tank body, the weld seam does not meet the welding requirements, etc.
- These factors will have an impact on the strength of the tank body of the bulk cement tanker, and the safety performance of the tanker will be greatly reduced.
Therefore, when cement tanker transportation companies purchase cement tankers, they must choose qualified products produced by qualified regular manufacturers.
Excessive pressure during bulk cement tanker operation
During the unloading process of the bulk cement tanker, it is necessary to exert pressure on the inside of the tank so that the material can be unloaded quickly, which leads to excessive pressure during the operation.
The causes of excessive pressure in the tank can be roughly divided into three categories:
- The unloading valve opens late in the pressurization stage before unloading, resulting in excessive pressure;
- The air supply volume at the initial stage of unloading is greater than the discharge volume of the tank, which may easily cause excessive pressure;
- Pipeline blockage during the unloading process will also cause excessive pressure.
In order to ensure the safety of the bulk cement tanker during the unloading process, the manufacturer will configure the following safety devices:
There is at least one set of pressure gauges, safety valves, air release valves, booster valves, etc. for each device on the vehicle. The functions of these devices are: the pressure gauge can monitor the pressure in the tank;
When the pressure in the pipeline and the tank exceeds the working pressure, the safety valve can automatically exhaust and reduce the pressure;
The air release valve is used for excessive pressure during the unloading process or artificial exhaust and pressure reduction after unloading; the booster valve can prevent pipeline blockage during the unloading process.
During the entire unloading process, the pressure gauge and safety valve play an important role in ensuring the safety of the pressure in the tank. Once both fail at the same time, the vehicle cannot automatically exhaust and reduce pressure, and it is very easy to explode due to excessive pressure in the tank.
Negligence of operators of bulk cement tanker
During the unloading process of the bulk cement tanker, the pressure in the tank is too high to cause the explosion of the tank body, which is often related to the negligence or lack of experience of the operators.
- During the entire unloading process, the operator needs to monitor the pressure in the tank and the unloading situation at all times. If the pressure in the tank is found to exceed the specified pressure, in order to ensure the safety of the operation, measures should be taken to reduce the pressure immediately;
- If the air compressor or pipeline valves are abnormal, take emergency measures immediately and stop working;
- If you need to open the tank cover of the tanker, you must ensure that there is no pressure difference between the inside and outside of the tank (that is, the pointer of the pressure gauge is “0”) to operate.
- When there is negative pressure in the tank, the cover will be difficult to open due to the huge pressure;
- If it is opened rashly under overpressure (positive pressure), accidents may occur in which the operator is shot and killed.
If the pressure gauge and the safety valve fail at the same time during the operation, experienced operators can usually judge according to the vibration of the discharge pipe and the pumping time, so as to take corresponding measures to complete the normal discharge.
Therefore, the cement tanker company should do a good job in relevant skill training for tanker drivers and operators, and have a sufficient understanding of the process to ensure the safety of unloading work.
In summary, the failure of production quality to meet the strength requirements of the tank body, failure of safety devices, negligence of operators or lack of experience are the main reasons for explosion accidents of bulk cement tankers. In view of these accident reasons, each cement tanker transportation company should take corresponding preventive measures to avoid accidents.
