Sliding friction resistance of API Std 650 special tank

Preheating should be performed by heating and maintaining this heat in appreciable lengths of the joint to be welded, preferably using a strip burner with a mild flame rather than a harsh flame such as that from a cutting torch. Electrical strip heaters are available and have been found to be satisfactory. The preheat of 300°F should be checked with a temperature-sensitive crayon, or similarly accurate means, so that the steel 4 in. (or four times the API Std 650 special tank plate thickness, whichever is greater) on each side of the joint will be maintained at the minimum preheat temperature. Ring burners or heaters are recommended for nozzle and manway welds. At no time during the welding should the base metal fall below a temperature of 300°F.

The tank wall design of API 650 oil storage tank. Since there is no ventilation pipe directly connected with the outside on the top of the API Std 650 special tank tank, the ventilation between the inside and outside of API 650 oil storage tank is realized by the respiration valve. The constant pressure of the respiration valve is 0.3kPa, so the pressure on the top of the tank is 0.3kPa.

Static storage loss is also known as "small breathing" consumption. The rise and fall of the temperature in the API Std 650 special tank leads to the increase and decrease of the pressure in the tank, which makes the mixed oil gas discharged from the tank, and the external air is sucked into the tank, resulting in the oil consumption. Fluid level loss is also called "big breathing" loss. It is the oil consumption caused by the change of gas space volume in the API Std 650 special tank during the oil receiving and sending operation, which causes the mixed oil gas to be discharged out of the tank, and the external air is sucked into the tank, resulting in the oil consumption due to the change of liquid level height.