Design of water tanks
Thread Content
Water with a weight of 15 kilograms flows through a DN80 pipe at a flow rate of 20 t/h, at room temperature. This water enters a tank at atmospheric pressure, with the top of the tank exposed to the atmosphere. Will water under such high pressure vaporize when it enters this tank at atmospheric pressure? How much can be vaporized? But there is a pipe leading to the atmosphere on top of the tank; is this a reasonable design for the tank? Should a safety valve be installed on the tank? Please advise, experts
In water at room temperature, a gas-containing medium will not vaporize if it is not dissolved; even when a gas-containing medium is present, vaporization does not occur, but rather desorption or flashing takes place. The top of the tank is connected to the atmosphere, so no safety valve is needed.
Oh, thank you ylb913. There is no gas in the water; it’s just ordinary soft water. The top of the tank is connected to the atmosphere through a DN100 pipe that is open to the outside air. I’m worried that a pressure of 15 kilograms per square centimeter might be too high, and that this could cause flashing once the water enters the tank at normal pressure. Also, if a large amount of vapor is generated, will the pipe leading to the atmosphere be able to release enough pressure?
Soft water at room temperature does not vaporize; the saturated vapor pressure of water depends only on temperature, and no matter what pressure is applied, the saturated vapor pressure corresponding to that water remains unchanged. The breathing in this tank is mainly due to changes in the liquid level and variations in water or air temperature; a DN100 vent is sufficient.
It will not vaporize; a vent pipe is required, but no safety valve is needed. The vent pipe serves to maintain a constant pressure inside the tank when the liquid level changes, thereby preventing the tank from collapsing or being damaged (it’s air pressure, not hydraulic pressure)； You can look into the concepts of flash vaporization and saturated vapor pressure; under normal water conditions, it does not vaporize ； The flow rate is a little over 1, which falls within the normal range. The heat generated by friction may raise the temperature a bit, but vaporization should not occur significantly.
Thank you for the reply from the 5th floor; it was explained in great detail
It is directly connected to a tank at atmospheric pressure; the water in the pipeline cannot reach 15 bar – the pressure is very low, so there’s no need to worry!