Water pump is a kind of machine which can transport or pressurize liquid. It transfers the mechanical energy or other external energy of the prime mover to the liquid so as to increase the energy of the liquid, which is mainly used for conveying liquid, including water, oil, acid and alkali liquid, emulsion, suspending emulsion and liquid metal.
It can also transport liquid, gas mixture and liquid containing suspended solids. The technical parameters of pump performance include flow, suction head, water-lift, shaft power, water power, efficiency, etc,; According to different working principles, it can be divided into volume pump and vane pump.Volume pump uses the change of working chamber volume to transfer energy.Vane pump uses the rotary blades and water interaction to transfer energy, there are centrifugal pump, axial flow pump and mixed flow pump.
Water pumps have different uses, liquid media, flow rates and lift ranges. Therefore, their structural forms and materials are different.There are many types of water pumps on the market, we will introduce some common pumps.
Common Water Pump
Sing-stage single suctions centrifugal pump (IS Type Water Pump)
IS type pump is a single-stage single suction centrifugal pump. It designed according to the international standard ISO2858. It is an updated product of BA type pump. It is suitable for industrial and urban water supply and drainage, as well as agricultural drainage and irrigation. It is used for transporting clear water or other liquids with similar physical and chemical properties. The temperature is not more than 80 ℃.
IS type water pump is mainly composed of pump body (1), pump cover (2), impeller (3), shaft (4), sealing ring (5), shaft sleeve (8) and suspension bearing parts (12).
Sing-stage double suctions centrifugal pump (S/SH Type Water Pump)
S/SH type water pump is a single-stage, double suction, centrifugal pump opened in the pump shell. It’s used for pumping clear water and liquid with physical and chemical properties. The pump water-lift is from 9m to 140m, and the flow is 126m3/h to 12500m3/h. The maximum temperature of the liquid shall not exceed 8O ℃. This pump is suitable for the plant, mine, urban water supply, power station, large water conservancy project, farmland irrigation and drainage. The 48SH-22 large pump can also be used as the circulating pump of thermal power station.
The meaning of pump model:
For example, 10SH-13A
10 — The suction diameter is divided by 25 (i.e. the diameter of the pump suction port is 250 mm).
S/Sh — Single stage horizontal centrifugal clean water pump with double suction
13 — The specific number is divided by 10 (i.e. the specific rotation number of the pump is 130)
A — Means that the pump has changed impeller with different outer diameter.
SH type water pumps rotate in a counter clockwise direction; S type pumps all rotate clockwise.
The main parts of S/SH type pump are: pump body (1), pump cover (2), impeller (3), shaft (4), double suction sealing ring (5), shaft sleeve (6) and bearing body (14).
Multi-stage centrifugal pump (D/DG/DM/DF/DY Type Water Pump)
Self priming pump is a single-stage single suction centrifugal pump which depends on the special structure of the pump itself. Compared with the ordinary centrifugal pump, there are significant differences in the structure of the pump body: one is the inlet position of the pump is increased, and sometimes the suction valve is installed; the other is a gas-water separation chamber is set on the water outlet side.
The external self-priming pump is equipped with self-priming devices, such as vortex pump, water ring vacuum pump, jet pump and manual pump.
Compared with ordinary centrifugal pump, self-priming pump has the advantages of compact structure and simple operation. It not only saves the trouble of filling a large amount of water before starting, but also saves the low valve of inlet pipe. It reduces the resistance of inlet water and increases the water output of pump. However, compared with ordinary centrifugal pump of the same specification, the efficiency of self-priming pump is 3% – 5% lower. Self priming pumps are mostly used in light and small sprinkler irrigation units and pipeline irrigation units.
Volume pump: Use the periodic change of working cavity volume to transport liquid.
Vane pump: Use the interaction between blade and liquid to transport liquid. Vane pumps include centrifugal pump, axial flow pump and mixed flow pump.
Working principle of centrifugal pump
Before the pump is started, fill the pump and water inlet pipe with water. After the pump is running, under the action of centrifugal force generated by the high-speed rotation of the impeller, the water in the impeller channel is dumped around, and it is pressed into the volute. The impeller inlet forms a vacuum. The water in the water tank is inhaled along the suction pipe under the external atmospheric pressure to supplement the space. Then the water inhaled is dumped by the impeller and then into the outlet pipe through the volute. Thus, if the impeller of centrifugal pump is rotating continuously, it can absorb water and press water continuously, and the water can be continuously lifted from the low to high or far away. In conclusion, centrifugal pump is because of the centrifugal force generated by the high-speed rotation of impeller, and the water is lifted to a high place, so it is called centrifugal pump.
Working principle of axial flow pump
The principle of axial flow pump is different from that of centrifugal pump, which mainly uses the thrust water produced by the high speed rotation of impeller. The lift force on water when the blade of axial flow pump rotates can push water from below to above.
The blades of axial flow pumps are generally immersed in the water pools where the water is absorbed. Because of the high speed rotation of impeller, under the lifting force generated by the blade, the water is pushed upward continuously, so that the water flows out along the outlet pipe. The impeller is constantly rotating, and the water is continuously pressed to the high place.
Working principle of mixed flow pump
Because the impeller shape of the mixed flow pump is between the impeller of centrifugal pump and the impeller of axial flow pump, the working principle of the mixed flow pump is centrifugal force and lifting force. The combined action of both sides makes water flow out of the impeller at a certain angle with the shaft, and the water is lifted to the high place through the volute chamber and pipeline.
Advantages and Features
The water is drawn in the axial direction of impeller along the flow direction of centrifugal pump, and flows out vertically in the axial direction.
Since the centrifugal pump is formed by the inlet of impeller, it is necessary to fill the pump and suction pipe with water before starting, or use vacuum pump to pump air to form vacuum. Besides, the pump shell and suction pipe must be strictly sealed and air leakage is not allowed, otherwise, it will not be vacuum, and water will not be absorbed.
Since absolute vacuum is not possible at the impeller inlet, the suction height of centrifugal pump cannot exceed 10 meters, and the along-line loss caused by water flow through the suction pipe, the actual allowable installation height (the height of the pump axis from the suction surface) is far less than 10 meters. If the installation is too high, it will not absorb water; In addition, because the atmospheric pressure in mountainous area is lower than that of plain, the installation height of the same water pump in mountainous area should be reduced, especially in high mountain area, otherwise water can not be absorbed.
Axial Flow Pump
The flow direction of water in the axial flow pump is along the axial suction and axial outflow of the impeller.
Low lift (1-13 m), large flow and high benefit. It is suitable for irrigation and drainage in plain, lake and river areas.
There is no need to fill water before starting, and the operation is simple.
Mixed Flow Pump
Compared with the centrifugal pump, the mixed flow pump has lower water-lift and larger flow. Compared with the axial flow pump, the mixed flow pump has higher water-lift and lower flow. It is suitable for irrigation and drainage in plain and lake areas.
Water along the flow direction of mixed flow pump and impeller shaft into a certain angle and suction and outflow.