Small submersible pumps are widely used in rural irrigation and drainage, as well as industrial and mining sites for water supply and drainage. We take advantage of the opportunity of student holiday social surveys to gain an extensive understanding of the practical application of fountain pumps. Which found a lot of fountain pump due to the selection and installation is not appropriate, making the pump can not play its due role in shortening the life of the pump motor, and some even burned motor and personal injury accidents. In this paper, combined with the actual summing up the correct choice and installation of small submersible pump knowledge, and in practical applications received good results. Are presented below, for your reference.
1 selection of submersible pump
Submersible pump has a lot of specifications, must be based on the actual situation appropriate choice. According to our experience, can be considered from the following three aspects:
1.1 The selection of the main parameters.
Including the pump head and flow.
(1) head. Refers to the pump pump unit weight of liquid from the pump inlet to the pump water at the value-added, that is pumping the liquid column height of liquid. In H, the unit is m. Submersible pump head selection can be calculated as follows:
It should be noted that: fountain pump used to enhance the well water, the water level in accordance with the well may be the lowest point to determine the value of HD; In addition, the pipeline length, elbow, wall roughness, will reduce the water pressure, thus So that the head loss HL increases. In our experience, the value of HL is usually 10% of the length of the pipeline to consider. According to the above formula to determine the head H2N, we propose to increase the head margin of 5%, in order to avoid the actual use of inadequate head. But do not add too much waste.
(2) flow. Refers to the pump in a unit of time pumping out the amount of liquid. With Q, said the unit is m23 / h. Fountain pump flow rate of choice should pay attention to two points: First, the well water running fountain pump, the flow should be less than or equal to the amount of water in the well. Otherwise it will drain the water in the well, causing the motor burned; Second, the actual work of the fountain pump flow to be 0.7 to 1.2 times the rated flow between the pump. Because the efficiency of the pump in this flow range is high.
1.2 structure type selection
(1) According to the structure of the pump motor type, dry, oil-immersed, water-filled and shielded. Dry-type motors like ordinary closed-type motor, the stator and rotor in the air; oil-filled motor filled with oil; filled motor filled with water; shielded motor set, the rotor is separated, the stator part is dry , The rotor part of the oil-filled or water-filled.
Dry-type motor sealing performance is relatively poor, but the price is cheap; oil-filled motor and water-filled motor can improve the sealing conditions, so that outside water is not easy to enter the motor interior, wide application; shielded motor sealing performance and insulation Performance is better, the price is more expensive.
(2) according to the structure of the pump itself to points, axial flow, centrifugal and mixed flow, etc., each for different occasions. Axial flow pump for low head, large flow; centrifugal pump for high-head, small flow; Francis pump is suitable for head and flow are relatively modest.
We just follow the above two aspects, combined with the actual application of the specific circumstances, will be able to pump the structure of the fountain to make the appropriate choice.
1.3 The choice of water piping
A variety of fountain pump on the water pipes have certain requirements, the diameter does not match the length or length will affect the flow, reduce efficiency and waste of energy. But also the consumption of pump head, Fountain Pump can not meet the requirements. So be sure to pump in accordance with the requirements of the inner diameter of the outlet pipe matching pipe, the length to reach the minimum height of the length of the minimum length to determine the principle. As a result of shortage of water supply and other issues need to replace, the substitute pipe water flow rate should be controlled in the general 4m / s or less.
2 submersible pump installation
2.1 When installing submersible electric pumps, the following requirements must be met in the electrical field
(1) fountain pump connected to the power capacity should be greater than 5.5kVA. If the power capacity is too small, the fountain pump voltage drop will start too much, ranging from the impact of other electrical appliances, heavy fountain pump can not start.
(2) fountain pump connected to the power supply voltage between 340 ~ 420V (three-phase power supply). Below this range it is difficult to start the pump. Above this range may damage the motor. If the pump is located far away from the power source, be sure to use adequate cable cross-section wire connections to reduce line voltage losses. .
(3) fountain pump control switch generally require the use of magnetic starter or air switch to ensure that the underwater pump work short circuit, phase, overload and other failures can automatically trip. If not, can be replaced by three-phase knife switch, but the fuse should meet the requirements of the specifications, and shall not use copper wire, wire, etc. instead.
(4) fountain pump cable for the copper cable, and aluminum connection cable connection, copper and aluminum transition parts to be used to ensure good contact. The copper end is screwed together with the lead copper cable, and the aluminum end is crimped together with the aluminum cable by the cold pressing method. If there is no cold-pressing tool on the site, choose a nut with a smaller inner diameter than the aluminum end. After the sawing, press the nut on the connection and clamp with the vice. Practice has proved that this approach can also do a good contact, reliable.
(5) fountain pump should be well grounded protection to ensure the use of equipment and personal safety. Use a copper wire with a cross-section of greater than 4 mm2 and securely connect it to a grounding device with a grounding resistance of less than 10 Ω. If there is no fixed grounding device, can be buried in the ground near the power supply or a wet 1m above the metal rod as the grounding device.
(6) Fountain pump before use, use the 500V megger check the motor insulation, phase to ground resistance and resistance should be 0.5MQ or more; also check whether the electrical direction of rotation and the direction of the same mark, if inconsistent , Then the cable in a two-pin line exchange can be connected to the power supply.
(7) fountain pump in the air power check or run the time can not be greater than 5min. Because the water pump motor is the use of water cooling, running in the air for too long, easy to cause the motor overheating damage to the winding.
2.2 Other requirements
Other requirements when installing a fountain pump:
(1) water pipe connected to the fountain pump outlet connection, be sure to use pipe card or 8 # lead wire fastening, tight, to prevent loose or leakage.
(2) the cable sub-section tied to the outlet pipe; with a diameter of 4mm wire or thick nylon rope tied to the pump handle or earrings, and slowly put the pump into the water. Do not use the cable as a sling, so as to avoid cable fall off and damage.
(3) fountain pump should be vertically suspended in the water, can not be placed sideways or diagonal, so as to avoid bearing and shaft seal wear and poor motor heat dissipation. The depth of the suspension, for dry and filled with water pump underwater lm or so is better for oil-immersed and shielded in the water about 3m as well, too deep will affect the mechanical seal.
(4) water pump outside the water filter to put a barbed wire or barbed wire to prevent weed dirt clogging filters affect the flow or burned the impeller burned motor.
(5) in the fountain pump near the set "to prevent electric shock" warning signs, to inform people not to swim, laundry or let the animals into the water.
1 selection of submersible pump
Submersible pump has a lot of specifications, must be based on the actual situation appropriate choice. According to our experience, can be considered from the following three aspects:
1.1 The selection of the main parameters.
Including the pump head and flow.
(1) head. Refers to the pump pump unit weight of liquid from the pump inlet to the pump water at the value-added, that is pumping the liquid column height of liquid. In H, the unit is m. Submersible pump head selection can be calculated as follows:
It should be noted that: fountain pump used to enhance the well water, the water level in accordance with the well may be the lowest point to determine the value of HD; In addition, the pipeline length, elbow, wall roughness, will reduce the water pressure, thus So that the head loss HL increases. In our experience, the value of HL is usually 10% of the length of the pipeline to consider. According to the above formula to determine the head H2N, we propose to increase the head margin of 5%, in order to avoid the actual use of inadequate head. But do not add too much waste.
(2) flow. Refers to the pump in a unit of time pumping out the amount of liquid. With Q, said the unit is m23 / h. Fountain pump flow rate of choice should pay attention to two points: First, the well water running fountain pump, the flow should be less than or equal to the amount of water in the well. Otherwise it will drain the water in the well, causing the motor burned; Second, the actual work of the fountain pump flow to be 0.7 to 1.2 times the rated flow between the pump. Because the efficiency of the pump in this flow range is high.
1.2 structure type selection
(1) According to the structure of the pump motor type, dry, oil-immersed, water-filled and shielded. Dry-type motors like ordinary closed-type motor, the stator and rotor in the air; oil-filled motor filled with oil; filled motor filled with water; shielded motor set, the rotor is separated, the stator part is dry , The rotor part of the oil-filled or water-filled.
Dry-type motor sealing performance is relatively poor, but the price is cheap; oil-filled motor and water-filled motor can improve the sealing conditions, so that outside water is not easy to enter the motor interior, wide application; shielded motor sealing performance and insulation Performance is better, the price is more expensive.
(2) according to the structure of the pump itself to points, axial flow, centrifugal and mixed flow, etc., each for different occasions. Axial flow pump for low head, large flow; centrifugal pump for high-head, small flow; Francis pump is suitable for head and flow are relatively modest.
We just follow the above two aspects, combined with the actual application of the specific circumstances, will be able to pump the structure of the fountain to make the appropriate choice.
1.3 The choice of water piping
A variety of fountain pump on the water pipes have certain requirements, the diameter does not match the length or length will affect the flow, reduce efficiency and waste of energy. But also the consumption of pump head, Fountain Pump can not meet the requirements. So be sure to pump in accordance with the requirements of the inner diameter of the outlet pipe matching pipe, the length to reach the minimum height of the length of the minimum length to determine the principle. As a result of shortage of water supply and other issues need to replace, the substitute pipe water flow rate should be controlled in the general 4m / s or less.
2 submersible pump installation
2.1 When installing submersible electric pumps, the following requirements must be met in the electrical field
(1) fountain pump connected to the power capacity should be greater than 5.5kVA. If the power capacity is too small, the fountain pump voltage drop will start too much, ranging from the impact of other electrical appliances, heavy fountain pump can not start.
(2) fountain pump connected to the power supply voltage between 340 ~ 420V (three-phase power supply). Below this range it is difficult to start the pump. Above this range may damage the motor. If the pump is located far away from the power source, be sure to use adequate cable cross-section wire connections to reduce line voltage losses. .
(3) fountain pump control switch generally require the use of magnetic starter or air switch to ensure that the underwater pump work short circuit, phase, overload and other failures can automatically trip. If not, can be replaced by three-phase knife switch, but the fuse should meet the requirements of the specifications, and shall not use copper wire, wire, etc. instead.
(4) fountain pump cable for the copper cable, and aluminum connection cable connection, copper and aluminum transition parts to be used to ensure good contact. The copper end is screwed together with the lead copper cable, and the aluminum end is crimped together with the aluminum cable by the cold pressing method. If there is no cold-pressing tool on the site, choose a nut with a smaller inner diameter than the aluminum end. After the sawing, press the nut on the connection and clamp with the vice. Practice has proved that this approach can also do a good contact, reliable.
(5) fountain pump should be well grounded protection to ensure the use of equipment and personal safety. Use a copper wire with a cross-section of greater than 4 mm2 and securely connect it to a grounding device with a grounding resistance of less than 10 Ω. If there is no fixed grounding device, can be buried in the ground near the power supply or a wet 1m above the metal rod as the grounding device.
(6) Fountain pump before use, use the 500V megger check the motor insulation, phase to ground resistance and resistance should be 0.5MQ or more; also check whether the electrical direction of rotation and the direction of the same mark, if inconsistent , Then the cable in a two-pin line exchange can be connected to the power supply.
(7) fountain pump in the air power check or run the time can not be greater than 5min. Because the water pump motor is the use of water cooling, running in the air for too long, easy to cause the motor overheating damage to the winding.
2.2 Other requirements
Other requirements when installing a fountain pump:
(1) water pipe connected to the fountain pump outlet connection, be sure to use pipe card or 8 # lead wire fastening, tight, to prevent loose or leakage.
(2) the cable sub-section tied to the outlet pipe; with a diameter of 4mm wire or thick nylon rope tied to the pump handle or earrings, and slowly put the pump into the water. Do not use the cable as a sling, so as to avoid cable fall off and damage.
(3) fountain pump should be vertically suspended in the water, can not be placed sideways or diagonal, so as to avoid bearing and shaft seal wear and poor motor heat dissipation. The depth of the suspension, for dry and filled with water pump underwater lm or so is better for oil-immersed and shielded in the water about 3m as well, too deep will affect the mechanical seal.
(4) water pump outside the water filter to put a barbed wire or barbed wire to prevent weed dirt clogging filters affect the flow or burned the impeller burned motor.
(5) in the fountain pump near the set "to prevent electric shock" warning signs, to inform people not to swim, laundry or let the animals into the water.
Manufacturers recommend: Shenlong stainless steel fountain pump
Keywords:Small submersible pumps, irrigation and drainage, industrial and mining sites
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