Misunderstanding in the use of centrifugal pump
1. High lift pump for low lift pumping
A lot of machine hand think pump head is lower, the motor load is smaller. Under the misleading understanding of this error, the purchase of a pump, the pump will be a high lift pump. In fact, for the centrifugal pump, when the pump model is determined, the size of its power consumption is proportional to the actual flow of the pump. And the pump flow will increase with the increase of head and reduce, and thus the higher the head, the smaller the flow, the smaller the power consumption. Conversely, the lower the head, the greater the flow, the greater the power consumption. Therefore, in order to prevent motor overload, the general requirements of the actual pumping water pump lift shall not be less than 60% of the calibration head. Therefore, when the high head is used for pumping low head, the motor is easy to overload and heat, and the motor can be burnt out when the time is serious. If the emergency use, it must be in the water outlet pipe is provided with a for regulating water valve, to reduce the flow to prevent motor overload. Pay attention to the temperature rise of the motor, if the motor overheating, should be promptly closed or shut down water outlet flow. It is also easy to misunderstand, some hand that blocking the outlet, forced to reduce the flow will increase the load of the motor. In fact, just the opposite, formal power centrifugal pump drainage and irrigation machinery of the outlet pipe is provided with a valve, in order to reduce the start-up of the motor load should be to close the valve, to be the motor start and then gradually open valve is the truth.
2. Large diameter pumps with small water pipes pumping
A lot of machine hand that can improve the actual head, in fact, the actual pump head = total head loss head. When determining the types of pumps, the total lift is certain; head loss mainly comes from the pipeline resistance, smaller diameter obviously, the greater the resistance, so the loss of lift more big so as to reduce the diameter of, really pump lift can not only increase, but will reduce the and, as a result, the decline in pump efficiency. Similarly, when a small diameter pump with large water pumping, it will not reduce the actual pump lift, but because the pipeline resistance decreases and the head loss, the actual head increased. Also organic hand think tubule diameter pumps with pumping pipe, will greatly increase the electrical load, they think the diameter increases, the water outlet pressure of the pump impeller is big, so it will greatly increase the electrical load. As everyone knows, only the size of the liquid pressure and the lift height, and the pipe cross-sectional area regardless of the size of. As long as the lift pump, impeller size unchanged, no matter how big the diameter, the pressure acting on the impeller are certain. Only the diameter increases, the flow resistance will decrease, while the flow rate increases, the power consumption is also increasing. But as long as the rated lift range, regardless of how to increase the diameter of water pump can work normally, and can also reduce the line loss, improve the efficiency of the pump.
3. Installation of water pipes, horizontal section or direction to water up
It will make the water inlet pipe gathered in the air, reduce the degree of vacuum pipe and water pump, to pump water head decreases, reduce the amount of water. The correct approach is: the horizontal section should be slightly inclined to the direction of the water level, should not, not up.
4. The inlet elbow for pipelines
If the elbow in the inlet pipe on the multi use, will increase the local flow resistance. We should turn and elbow in the vertical direction, are not allowed to turn in the horizontal direction, so as to avoid the accumulation of air.
5. Water inlet and the elbow is directly connected
This will make the water flow through the elbow into the impeller when the uneven distribution of. When the inlet diameter is greater than the pump inlet, eccentric reducer should be installed. Eccentric adjustable tube mounted on a flat part to the above, the inclined part installed in the following. Or gather air, reduce the amount of water or no water, and crash. If water is the same as the diameter of the pipe and the water inlet of the water pump should be between the water inlet of the water pump and the elbow and straight pipe and straight pipe length shall not be less than 2 ~ 3 times the pipe diameter, the.
6. Equipped with bottom valve inlet pipe the next section is not vertical.
Such as installation, the valve can not be closed, resulting in Water Leakage. The correct installation method is: a water inlet pipe valve, the next best is vertical. As a result of the terrain conditions can not be installed in a vertical pipe is the axis angle with the horizontal plane should be more than 60 degrees.
The water inlet of the water inlet pipe 7 position is wrong
(1) the water inlet of the water inlet pipe from the bottom of the pool and the pool wall distance is less than the diameter of the inlet. If the inlet water poor or sucked into sediment debris in a sediment and dirt at the bottom of the pool and 1.5 times the distance from the water inlet from the bottom of the pool is less than the diameter of the, resulting in pumping, clog water intakes.
(2) the water inlet pipe of the water inlet into water depth is not enough, this will cause water inlet pipe around the surface of the water swirls and eddies of, the impact of water, to reduce the amount of water. The correct installation method is: water depth into the small water pump shall not be less than 300 ~ 600mm, large pump shall not be less than 600 ~ 1000mm.
The 8 water outlet in the above normal water pool
If the outlet in the pool above the normal water level, although the increase of the pump head, but reduces the flow. As a result of terrain conditions limited. The water outlet must be high out of the water level of the water, the nozzle installation of elbows and short, the pipes become siphon type, lower water outlet
