Special lecture on mechanical equipment: “Pumps” – Learn a little every day (9): Self-priming pumps and pump materials “Improve yourself””

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This post was last edited by A’dai A’mu on 2013-12-12 at 12:34, with the aim of encouraging more active participation in discussions and more diligent learning. Here, the top five users each time will receive a “Diligent Learning Reward.” There are also series of lectures on mechanical equipment, focusing on pumps; daily summaries of knowledge are provided, and these posts are updated continuously: http://bbs.hcbbs.com/thread-1256318-1-1.html. Some people might think that spending their working days doing trivial tasks, not knowing what to do or what to learn, day after day, year after year, with no vision for their future – it’s a terrifying situation! We must start working hard from now on; even if we learn a little knowledge every day, it will add up over time and help us enrich ourselves. We need to set clear goals – only by filling our minds first can we enrich other aspects of our lives as well. . . . . . Just spend a short ten-odd minutes every day, and you will see the future! ! ! (Anyway, I have learned it; whether you learn it or not is up to you. Those who know it include that master Hai Chuan, aside from others. . . ) Enough talk – let’s start with the basics today~~! I’ve been posting special threads for so many days now; I’m sure everyone has benefited a lot from them. Thank you all for your support~~! Welcome everyone to listen. I have started broadcasting, and I hope those who, like me, want to gain knowledge every day will listen. Let’s learn together every day and discuss~~! These past few days, many people have asked various questions, and I’ll do my best to answer them all. There may be some questions I haven’t encountered before, but there are still plenty of people in our community who can help answer them. @AidaiAmu @hcwang12345 @YiHuXiangMing @tjdxz @YouDianDai @NewbiesInHaiChuan @lovestory @ManTianYun @zhaoqingsheng The most common questions I’ve been asked these days are regarding self-priming pumps and metal materials; so today I’ll dedicate two articles to each of these topics. Self-Priming Pumps: Principles and Model Information 1. Principles of Self-Priming Pumps Self-priming pumps possess a certain ability to self-priming, which enables them to start operating easily even when there is no water available for suction, and allows them to maintain normal operation. The self-priming pumps currently produced in our country are basically self-priming centrifugal pumps. Based on the different methods used for self-priming, self-priming pumps can be divided into external mixing type self-priming pumps, internal mixing type self-priming pumps, and vacuum-assisted self-priming pumps that utilize power provided by the pump itself. Depending on the liquid to be transported and the material used, there are various types of self-priming pumps such as sewage self-priming pumps, clean water self-priming pumps, corrosion-resistant self-priming pumps, and stainless steel self-priming pumps. As shown in the figure, this is the basic structure of a (external mixing type) self-priming pump. Its main components include: pump body, pump cover, impeller, shaft, bearings, etc. The pump body features a vortex-shaped flow channel, with a larger-volume air-water separation chamber surrounding the outer layer of this channel. A base angle is cast at the lower part of the pump body for fixing it in place. The working principle of the external mixing type self-priming pump is the same as that of all self-priming pumps. The suction inlet of this type of pump is located above the impeller; after each shutdown, some water remains inside the pump to be used for the next start-up. Before the first start-up, sufficient priming water must be manually added to the pump so that most of the impeller is submerged in water. After the pump starts, the water inside the impeller is forced by centrifugal force toward the outer edge of the impeller, where it mixes with the gas to form a ring of foamy gas-water mixture. Under the scraping action of the baffle, this foam strip allows the gas-water mixture to enter the gas-water separation chamber through the diffusion tube. At this point, as the water flow area suddenly increases, the flow velocity drops rapidly. Gas, having a lower relative density, escapes from the water and is discharged through the pump outlet, while water, with a higher relative density, settles at the bottom of the gas-water separation chamber and returns to the outer edge of the impeller via the axial return holes, where it mixes again with the gas. As the above process repeats continuously, the vacuum level inside the suction pipe increases, causing the water being transported to rise upward along the suction pipe. Once the pump is completely filled with water, it enters normal operating mode and completes the self-priming process. The inlet and outlet of the pump body can be connected using rubber hoses or flanged pipes. When connecting the glue tube, the inlet tube connector seat is equipped with a check valve to prevent liquid from flowing back when the machine stops. The pump body’s vortex flow channel is equipped with a closed single-stage impeller; the pump cover contains a sealing chamber. Grease is placed inside the bearing housing to lubricate the bearings. At the rear end of the pump shaft, there is a V-belt pulley or coupling, and an electric motor or internal combustion engine is used to drive the pump. II. Structural diagram of the self-priming pump III. Models of self-priming pumps (examples). Self-priming pumps are divided into KD-type coaxial self-priming acid and alkali resistant pumps, and KDL-type coupled self-priming acid and alkali resistant pumps. Features of the KD type coaxial self-priming acid-alkali resistant pump: Made of FRPP/PVDF material, it offers strong corrosion resistance and is capable of withstanding strong acids and alkalis. The impeller features an integrated design, resulting in high flow rates and high head pressure; it is also durable, overcoming the shortcomings of traditional welded designs. The rear cover and base are integrally designed, facilitating maintenance and easy assembly. It features a unique shaft seal design with a self-cooling mechanism, eliminating the need for external cooling. It has a strong self-priming capacity, with a self-priming height of over 5 meters, and is equipped with a check valve to prevent backflow of liquid inside the pump. . The structure is specially reinforced, eliminating drawbacks such as temperature rise, deformation during prolonged operation, and leakage. Product description: Chemical liquid, for circulation or transfer processes. Electroplating, chemicals, leather, dyeing and finishing, wastewater treatment, exhaust gas treatment, etc. .The FRPP material can withstand temperatures up to 80°C, while the PVDF material can withstand temperatures up to 90°C. A bottom valve should be installed at the inlet to prevent the intake of foreign objects, while a check valve should be installed at the outlet to avoid sudden backflow when the pump stops operating, which could cause damage to the pump itself and lead to damage due to the pump running idle. Features of the KDL type coupled self-priming acid and alkali-resistant pump: Made of FRPP/PVDF material, it offers strong corrosion resistance as well as tolerance to strong acids and alkalis. The impeller features an integrated design, resulting in high flow rates and high head pressure; it is durable and overcomes the shortcomings of traditional welded designs. The rear cover and base are integrally designed, facilitating maintenance and easy assembly. . A unique shaft seal design with a self-cooling mechanism, eliminating the need for external cooling. It has a strong self-priming capacity, with a self-priming height of over 5 meters, and is equipped with a check valve to prevent liquid from flowing back into the pump. . The structure is specially reinforced, eliminating drawbacks such as temperature rise, deformation during prolonged operation, and leakage. Product description: Chemical liquid, for circulation or transfer processes. Electroplating, chemicals, leather, dyeing and finishing, wastewater treatment, exhaust gas treatment, etc. .The FRPP material can withstand temperatures up to 80°C, while the PVDF material can withstand temperatures up to 90°C. A bottom valve should be installed at the inlet to prevent the intake of foreign objects, while a check valve should be installed at the outlet to avoid sudden backflow when the pump stops operating, which could cause damage to the pump itself and lead to damage due to the pump running idle. IV. Application Areas of Self-priming Pumps Self-priming pumps are mainly used for chemical liquids, as well as in circulation and transfer processes. Electroplating, chemicals, leather, dyeing and finishing, wastewater treatment, exhaust gas treatment, etc. V. Use and Maintenance (1) Check whether the installation surface of the unit is level. Suction pumps do not require foundation bolts. (2) The connection between the inlet pipeline and the pump must have good sealing; air ingress is not allowed, as this can affect the pump’s flow rate or result in no water being delivered. (3) After the unit is installed, check whether there is any sticking in the rotor components and whether they rotate smoothly, and also verify that the rotation direction of the pump is correct. Rotation direction of this series of pumps: it rotates clockwise when viewed from the direction of the motor. (4) Pour the liquid in from the liquid filling port of the pump. Until liquid starts to overflow from the overflow tube. Then tighten the fill plug. Prevent air leakage from affecting the self-priming performance. (5) If the pump is not used for an extended period before being restarted, it is necessary to check whether there is sufficient liquid stored; if not, top it up. It should be filled with liquid before turning it on. (6) When the suction lift is too high, the density is high, and there is significant pressure in the discharge pipeline. To accelerate exhaust and reduce the self-priming time. After the pump starts, please open the valve on the exhaust port. (7) When transporting turbid water containing large suspended solids or large-particle media, the filter screen provided as standard must be installed. (8) When the pump is in operation, its flow rate, head, and suction lift must be strictly controlled within the ranges specified for the selected model. Operation in areas with extremely high flow rates is not allowed, to prevent cavitation and to avoid damaging the motor’s lifespan (in my system, the self-priming pump in the circulating water recovery tank is used to regulate the outlet pressure to 0.35 MPa). (9) During installation, the inlet and outlet pipelines must not be supported on the flanges at the pump’s inlet and outlet; the weight of these pipelines should be borne by fixed supports. (1O) The installation height of the water pump should ensure that it is below the pump’s allowable suction depth when operating at the lowest water level. (11) To ensure the performance of the self-priming pump, the diameters of the inlet and outlet pipes of the pump must not be altered without permission. (12) The self-priming pump should be started with the valve open to facilitate exhaust during the priming process. (13) The amount of liquid stored in the self-priming pump is limited; prolonged self-priming with no liquid flow will cause the liquid to heat up, which affects the achievement of a sufficient vacuum level and prevents self-priming. The horizontal section of the suction pipe for a self-priming pump should not be too long; try to install the pump at the beginning of the horizontal pipe. Below are my special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (16): Pneumatic diaphragm pumps “Improve your knowledge” http://bbs.hcbbs.com/thread-1257985-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (15): Pneumatic diaphragm pumps “Improve your knowledge” http://bbs.hcbbs.com/thread-1257433-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (14): Mixed-flow pumps “Improve your knowledge” http://bbs.hcbbs.com/thread-1257224-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (13): Axial flow pumps “Improve your knowledge” http://bbs.hcbbs.com/thread-1256970-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (12): Jet vacuum pumps “Improve your knowledge” http://bbs.hcbbs.com/thread-1256707-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (11): Automotive pumps “Improve your knowledge” http://bbs.hcbbs.com/thread-1256253-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (10): Pump materials “Improve your knowledge” http://bbs.hcbbs.com/thread-1255790-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (9): Self-priming pumps and pump materials “Improve your knowledge” http://bbs.hcbbs.com/thread-1255635-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (8): Oil seals “Improve your knowledge” http://bbs.hcbbs.com/thread-1255340-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (7): Seals “Improve your knowledge” http://bbs.hcbbs.com/thread-1255132-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (6): O-rings “Improve your knowledge” http://bbs.hcbbs.com/thread-1254912-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (5): Pump structure “Improve your knowledge” http://bbs.hcbbs.com/thread-1254630-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (4): Pump structure “Improve your knowledge” http://bbs.hcbbs.com/thread-1254625-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (3): “Improve your knowledge” http://bbs.hcbbs.com/thread-1253809-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (2): Schematic diagram of centrifugal pumps “Improve your knowledge” http://bbs.hcbbs.com/thread-1253590-1-1.html. Special series lectures on mechanical equipment focusing on “pumps” – learning a little something every day (1): Pump selection “Improve your knowledge”. These are my special posts; I will continue to update them daily. Please give me your support, listen, and discuss ； If there’s any direction that needs to be explained, feel free to contact me. If many people ask for it, I’ll create a separate post to go over it~~! :) A series of special lectures on mechanical equipment titled “Pumps” – a summary post with new knowledge shared every day, continuously updated at http://bbs.hcbbs.com/thread-1256318-1-1.html. Everyone is welcome to listen; I’ve already started broadcasting these sessions, and I hope those who, like me, want to gain knowledge every day will tune in. Let’s learn together every day and discuss~~!