The technical parameters of water pump performance include flow rate, suction lift, head, shaft power, water power, efficiency, etc. Among them, what is the difference between pump lift and suction? Let's compare.
Assuming that a pump has a suction lift of 5M and a head of 20M, the head of the pump when it is placed below the liquid level is set to H1, when the pump is at the same level as the liquid level, the head is H2, and when the pump is higher than The head when the liquid level is 4M is H3. What is the relationship between the values of H1, H2, H3, and 20M?
As long as it is ensured that the water loss of the suction pipe does not exceed 1 meter when it is 4M above the liquid level, the heads H1, H2, and H3 in the three cases are all 20M.
Suction range, also called high suction, refers to the pumping capacity, that is, how deep the water surface is from the pump to get water. It is also called the "maximum self-priming height" (it can also be understood as the "degree of self-priming"). That is, the maximum height at which the micropump can automatically suck water up (the distance between the pump suction port and the liquid surface to be pumped) without water diversion. Vertical distance).
The head also refers to the drainage height, which refers to the drainage capacity, that is, how high the water can be pumped. The head of a pump refers to the height at which the pump can lift water, usually expressed in H, and the unit is m. The head of a centrifugal pump is based on the center line of the impeller and consists of two parts. The vertical height from the center line of the pump impeller to the water surface of the water source, namely The height at which the pump can suck water up is called the suction lift, or suction lift for short; the vertical height from the center line of the pump impeller to the water surface of the outlet pool, that is, the height at which the pump can press the water up, is called the water pressure lift, or pressure range for short.
water pump head = suction head + pressurized water head
It should be pointed out that the head marked on the nameplate refers to the head that the pump itself can produce. It does not contain the loss head caused by the frictional resistance of the pipeline water flow. When choosing a water pump, pay attention to it. Otherwise, you will not be able to pump water.
How high the head is has nothing to do with whether the atmospheric pressure is used, it is related to the performance of the pump.
The 10 meter limit is mainly for the suction lift. Usually, the suction lift limit of the pump is about 10 meters at 1 atmosphere.
Generally, when the water source is lower than or equal to the position of the pump, the pump needs to have self-priming ability. For example, when traveling outdoors, it is necessary to pump water from the river. It is best to use a miniature pump with self-priming ability (it is impossible for people to run into the river first Add some water to the inlet pipe). Or the pumped liquid is corroded and it is not convenient to add water.
For example: there is a kind of water pump, the model is called XX BSP series, the volume is not large, but the nominal suction range can reach 4 meters, it is indeed possible to do not add water to 4 meters, which is relatively high in the micro pump.
In the micro water pump, not all pumps have self-priming capability ("suction lift").
Some centrifugal water pumps do not have the self-priming ability. You must add water for the first use. Although some micro-pumps also have self-priming ability, the standard "suction" is often the same as "the inlet pipe is all air". There is a difference in the vertical height of the pumped water, and it may even be less than half. Therefore, the suction stroke is a more important parameter when selecting the pump.
The relationship between suction and head of self-priming pump
The suction length of the self-priming pump refers to the vertical height from the low liquid level of the self-priming pump inlet to the self-priming pump. The loss of the suction stroke and horizontal distance of the self-priming pump needs to be based on the size of the pipe, the number of elbows, and the combination The flow rate of the self-priming pump is additionally calculated for loss.
The head of the self-priming pump is actually in the suction head data. For example, the head of the self-priming pump is marked as 15 meters. In addition, the suction head is lost by 3 meters in actual use. Then you need to use the head 15 meters-the suction head 3 meters to get the result. This is the actual head that this self-priming pump can achieve in use. In short, the greater the suction head loss, the lower the head of the self-priming pump. Many users and sales personnel of manufacturers do not understand this principle, so when selecting This important detail is ignored. For example, the head loss required by the on-site working conditions is 15 meters, and the suction lift of the self-priming pump needs 4 meters. Then, when choosing the head of the self-priming pump, the choice is based on 15 meters. In this case, when the self-priming pump is purchased and installed and put into use, the head of the self-priming pump will not reach 15 meters. Many users will think that the head of the self-priming pump cannot reach, but it is actually the suction of the self-priming pump. The process loss of the self-priming pump head, so when choosing the self-priming pump model, the suction stroke of the self-priming pump should be calculated. This is also the necessary professional knowledge for a self-priming pump salesperson. If you know the required self-priming For the height and required head, the two data should be added when selecting the type. The data obtained is the self-priming pump head that should be selected.
