Pump selection
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Pressure inside the tank: -0.02 Mpa, temperature: 95–100°C; the medium is waste condensate with a density of 1.1. The water volume in the tank is 0.6 m³, with automatic water replenishment. Pump parameters: flow rate 25 m³/h, head 35 m. As shown in the structure below, I have some questions I would like to ask the seniors. 1. If a horizontal pipe centrifugal pump is used, will the negative pressure inside the tank affect the pump’s lifespan? 2. Will the overall negative pressure inside the tank affect the head of the water pump? 3. What kind of water pump should be used for normal selection?
1. The negative pressure inside the tank can affect the suction efficiency and lifespan of horizontal pipeline centrifugal pumps, as the pump needs to overcome this negative pressure in order to draw in water. 2. The overall negative pressure inside the tank affects the pump’s effective head, as additional energy is required to overcome the pressure difference within the tank. 3. Normally, it is advisable to use a self-priming pump made of corrosion-resistant material that can withstand a certain degree of negative pressure and function under high-temperature conditions, or a centrifugal pump equipped with a pressurization device. .
It is recommended to first standardize this unit value of \"0.6 m³\“. Find a reputable equipment manufacturer – they have product selection tables, and it’s best to contact their technical support team, as they will be able to give you recommendations. For reference.
Horizontal centrifugal pumps can be used. Consider the necessary cavitation parameters for the equipment and pumps.
The mechanical seal of the centrifugal pump breaks after just two or three days of use; I’m not sure whether it’s caused by negative pressure or by a quality issue with the pump itself
The negative pressure in a turbine condenser is much higher than this; the condensate pump operates normally. It is recommended to use a condensate pump, whose design features ensure its ability to function in a vacuum environment. In addition, a condensate water tank is installed at the pump inlet, the pump is placed at a lower level, and vacuum valves are used for the valves in the vacuum system
Just pay attention to the installation height of the pump.
When selecting a pump, it is necessary to check whether the net positive suction head is sufficient
Negative pressure leakage and dry friction of the mechanical seal lead to rapid damage; a canned pump can be an alternative. In addition, the pump inlet must have sufficient static head, that is, the installation height must be enough to overcome cavitation