How did these explosions happen?
The answer is: when these centrifugal pumps are running, the inlet valve and the outlet valve of the pump have been closed at the same time (making the pump "idle"). Since water cannot flow out through the pump, all the energy originally used for fluid transportation is converted into heat. When the water is heated, a static pressure is generated inside the pump, which is sufficient to cause damage to the centrifugal water pump-seal damage may occur and the pump body may break. Due to the release of the energy accumulated in the pump, such an explosion may cause serious equipment damage and personal injury. However, if the water is heated above the boiling temperature before the pump is damaged, there may be a greater energy explosion, because the superheated water released at this time will quickly boil and expand (boiling liquid expansion vapor explosion-BLEVE ), its severity and hazard are similar to steam boiler explosion.
If the pump is running and the inlet and outlet valves of the pump are closed, no matter what kind of liquid the pump is delivering, this type of explosion may occur. Even non-hazardous fluids such as water produce the serious hazards shown in the picture. Imagine that if the fluid is flammable, the released material will catch fire and the consequences will be more serious. It is further envisaged that if the fluid is toxic or corrosive, the released material may cause serious injury to people near the pump.
What can you do before the pump explodes?
Before starting the centrifugal water pump, check whether all valves are in the correct position. Make sure that the valves on the designed flow path are all open, while other valves, such as drain valve and drain valve, should be closed.
If you want to start a pump remotely, for example from the control room, make sure that the pump you are about to start is ready to start. If you are not sure, you should go to the scene to check, or ask others to check.
It is important to ensure that the key steps that are critical to the safe operation of the pump, including the switch position of the valve, are included in the equipment's operating procedures and checklist.
Some pumps are automatically started, for example, when the storage tank is full, the process control computer or liquid level control instrument automatically empty the storage tank. Before putting these pumps into automatic control, such as after maintenance, make sure that all valves are in the correct position.
In order to prevent starting the pump when the pipeline is disconnected, some pumps are equipped with instrument protection devices-for example, low flow, high temperature, or overpressure and other interlocks. Make sure that these safety systems are properly maintained and tested.