Pump stability management in the process industry can be divided into three stages:<\/p>\n
1) Pump selection and stability determination before installation;<\/p>\n
2) Preparation for startup;<\/p>\n
3) Ensuring stability after startup. For centrifugal pumps to operate more effectively and stably, they need to do a good job in the following 10 aspects.<\/p>\n
1. Pump Selection<\/strong><\/p>\n As long as the centrifugal pump is operated under conditions close to the design conditions, good performance and maintenance intervals can generally be achieved. However, it should be noted that “design” refers not only to pressure, flow, temperature and other process parameters, but also to pressure and movement of flanges, pressure and movement of couplings, lubrication of bearings and similar mechanical factors. Pumps with old designs can only be operated for a short time under non-design conditions, and then the performance level of the pump will decrease. Therefore, pumps that operate near the maximum efficiency point (BEP) should be selected.<\/p>\n Centrifugal pumps with high suction specific speeds can usually only achieve good operating conditions within a narrow range. In high-head water pumps that try to use large impeller inlets to reduce NPSHR, backflow will occur.<\/p>\n Pumps with low NPSHR have suction specific speeds of around 12,000. If the normal flow rate deviates from the BEP flow rate, internal backflow will occur, making the pump less stable. Turbulence can cause erosion of the impeller and mechanical seal action, bearing loads and shaft deflection. The expected service life of centrifugal pump components is affected by many factors, including the pump’s suction specific speed, flow percentage (Qactual\/QBEP), NPSH margin (NPSHA-NPSHR), head rise in each stage and pump casing design. User demand for efficient, low-cost and low-NPSHR pumps has driven suction specific speeds above 12,000, at which point the actual flow rate deviates less from the BEP flow rate. The ideal suction specific speed of a pump should be around 8,500.<\/p>\n 2. Seal selection<\/strong><\/p>\n Packing seals have withdrawn from the historical stage, mechanical seals and dry gas seals have been widely used, and mechanical seals are commonly used. Mechanical seals are very mature in terms of products and technology. The material of the sealing end face must be able to quickly transfer the generated heat to prevent the fluid from evaporating. Silicon carbide is the first choice for sealing end face materials due to its high thermal conductivity and high hardness. The flushing solution of the seal needs to be carefully considered when selecting a pump.<\/p>\n 3. Pipe pressure<\/strong><\/p>\n When the pipe is bolted together with the flange of the pump casing, external pressure caused by the weight of the pipe, thermal expansion and the weight of the process fluid will exert pressure on the pump. These pressures will cause the pump casing to deform, causing internal offsets, causing friction between the pump casing, impeller and shaft, and even stalling of the shaft. They will generate torque around the pump, causing deviations between the pump and the drive shaft, which will cause premature failure of the coupling, bearing or mechanical seal. Therefore, limits must be set for the pressure and torque of these pipes. For pipeline designers, these limits are the maximum pressure values \u200b\u200bthat the pipeline can exert on the pump.<\/p>\n 4. Storage<\/strong><\/p>\n After the pump is correctly designed and ordered, the seller will send the pump to the buyer and wait for installation. All pumps are wrapped with waterproof tarpaulins, making sure that the tarpaulins completely cover the upper and lower ends of the pump to prevent the bearings and couplings from being stained with dust. The pump should be placed in a rainproof and dustproof place to avoid dust accumulation and moisture.<\/p>\n 5. Pump location<\/strong><\/p>\n The correct location of the pump is important for the operating point and maintenance point. To ensure good flow conditions, the pump should be as close to the liquid supply end as possible. If there is enough space, the pump inlet should be lower than the liquid level of the supply liquid. Leave enough space around the pump for inspection and maintenance. Leave enough space at the top of the pump to lift the heaviest parts of the pump using a high-level crane and chain hoist. Install the pump in a clean and dry place, and try to avoid dirty, dusty or damp spaces.<\/p>\n 6. Foundation<\/strong><\/p>\n The foundation of the pump must be carefully designed to ensure that the load of the pump and its driver does not exceed the bearing capacity of the soil. Almost all pumps are installed on concrete foundations because this material is low cost and very strong.<\/p>\n 7. Pump Installation<\/strong><\/p>\n One of the most critical factors in the successful operation and maintenance of pumps of all grades and types is correct installation. A properly installed pump can remain in the calibrated position for a long time, with less leakage and vibration from the pump casing and flanges.<\/p>\n 8. Pipeline Connections<\/strong><\/p>\n The loads and stresses imposed by the piping system can greatly affect the stability of the equipment. Loads caused by pipe expansion or other reasons can cause shaft deviation, pump casing deformation, and mutual interference of internal rotating parts. Therefore, the less stress the piping system imposes on the equipment, the better.<\/p>\n 9. Pipeline cleaning<\/strong><\/p>\n There are gaps between the rotating parts of the pump, and it is necessary to prevent abrasive particles in the new pipeline system from damaging them. Abrasive particles deposited in the rotating gap of the pump will cause the pump to shut down and the maintenance cost is very high. In order to reduce the possibility of abrasive particles entering the pump, a filter is generally installed.<\/p>\n 10. Calibration<\/strong><\/p>\n Bring the pump to its operating temperature by introducing liquid into the pump housing. When checking the calibration, check the rotation of the motor and pump. The pump should rotate in the direction of the arrow on the pump housing. Misalignment may cause:<\/p>\n 1) Overload of the pump bearings;<\/p>\n 2) Axial rotation of the mechanical seal back and forth. The more the seal moves, the easier it is for the overlapping seal faces to open;<\/p>\n 3) If the misalignment is severe, the stationary and moving parts will come into contact;<\/p>\n 4) Wear ring contact;<\/p>\n 5) Impeller and volute contact each other.<\/p>","protected":false},"excerpt":{"rendered":" Pump stability management in the process industry can be divided into three stages: 1) Pump selection and stability determination before installation; 2) Preparation for startup; 3) Ensuring stability after startup. For centrifugal pumps to operate more effectively and stably, they need to do a good job in the following 10 aspects. 1. Pump Selection As […]<\/p>","protected":false},"author":4,"featured_media":1362,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[36],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/www.tflequip.com\/et\/wp-json\/wp\/v2\/posts\/1361"}],"collection":[{"href":"https:\/\/www.tflequip.com\/et\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tflequip.com\/et\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tflequip.com\/et\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tflequip.com\/et\/wp-json\/wp\/v2\/comments?post=1361"}],"version-history":[{"count":0,"href":"https:\/\/www.tflequip.com\/et\/wp-json\/wp\/v2\/posts\/1361\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.tflequip.com\/et\/wp-json\/wp\/v2\/media\/1362"}],"wp:attachment":[{"href":"https:\/\/www.tflequip.com\/et\/wp-json\/wp\/v2\/media?parent=1361"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tflequip.com\/et\/wp-json\/wp\/v2\/categories?post=1361"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tflequip.com\/et\/wp-json\/wp\/v2\/tags?post=1361"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}