Selection and configuration of spare parts at year-end? (Participation reward: 10–30 wealth points)

Air compressor filters should be kept on hand.

Pump selection: When designing equipment, the design institute must determine the purpose and performance of the pump and select the appropriate type. This choice starts with selecting the type and design of the pump. So, what principles should be used to choose a pump? What is the basis then? I. Principles for pump selection 1. Ensure that the type and performance of the selected pump meet the requirements of the process parameters such as flow rate, head, pressure, temperature, net positive suction head, and suction lift of the installation. 2. The requirements of the medium’s properties must be met. For pumps used to transport flammable, explosive, toxic, or valuable fluids, it is necessary to have reliable shaft seals or to use leak-free pumps such as magnetically driven pumps, diaphragm pumps, and shielded pumps. For pumps used to transport corrosive fluids, the components that come into contact with these fluids must be made of corrosion-resistant materials; examples include AFB stainless steel corrosion-resistant pumps and CQF engineering plastic magnetically driven pumps. For pumps that transport media containing solid particles, it is required that the convective components be made of wear-resistant materials, and where necessary, the shaft seals should be flushed with a clean liquid. 3. High reliability in terms of mechanics, low noise, and minimal vibration. 4. Economically, it is necessary to take into comprehensive account the total cost of equipment costs, operating costs, maintenance costs, and management costs to minimize it. 5. Centrifugal pumps feature high speed, small size, light weight, high efficiency, large flow rate, simple structure, pulse-free fluid delivery, stable performance, ease of operation, and convenience in maintenance. Therefore, except in the following cases, centrifugal pumps should be preferred as much as possible: when metering is required, metering pumps should be used. When a very high head is needed along with a low flow rate, and no suitable centrifugal pump with a high head for low flow rates is available, reciprocating pumps can be chosen; vortex pumps can also be used if cavitation requirements are not high. When the head is very low but the flow rate is high, axial flow pumps and mixed-flow pumps can be utilized. When the viscosity of the medium is high (greater than 650–1000 mm2/s), a rotary pump or reciprocating pump (gear pump, screw pump) can be considered. When the medium contains 75% air, the flow rate is low, and the viscosity is less than 37.4 mm2/s, a vortex pump can be used. In situations where starting is frequent or pumping is inconvenient, pumps with self-priming capabilities should be used, such as self-priming centrifugal pumps, self-priming vortex pumps, and pneumatic (electric) diaphragm pumps. II. Criteria for Pump Selection The criteria for selecting a pump should be considered from five aspects, based on the process flow and water supply/distribution requirements: fluid flow rate, head of the system, properties of the fluid, pipeline layout, and operating conditions. 1. Flow rate is one of the key performance parameters for choosing a pump, as it directly affects the production capacity and transfer capacity of the entire system. If the process design in the design institute can calculate the normal, minimum, and maximum flow rates of the pump. When selecting a pump, the maximum flow rate should be taken as the basis, while also considering the normal flow rate. In cases where a maximum flow rate is not available, 1.1 times the normal flow rate can generally be used as the maximum flow rate. 2. The head required by the installation system is another important performance parameter for selecting a pump; generally, the head value should be increased by 5%–10% as a safety margin when making the selection. 3. Properties of the liquid, including the name of the liquid medium, its physical properties, chemical properties, and other characteristics. Physical properties include temperature, density, viscosity, the diameter of solid particles present in the medium, and the gas content; these factors are relevant to determining the system’s head pressure, the effective net positive suction head, and the appropriate type of pump. Chemical properties refer mainly to the chemical corrosiveness and toxicity of the liquid medium, and they serve as important criteria for selecting the material for the pump as well as the type of shaft seal to use. 4. The pipeline layout conditions of the plant system refer to data such as the liquid delivery height, distance, and direction; the lowest liquid level on the suction side and the highest liquid level on the discharge side; as well as details regarding pipe specifications, their lengths, materials, fitting specifications, and quantities. These are necessary for calculating the system head and verifying the net positive suction head. 5. There are many aspects related to operating conditions, such as the operating temperature of the liquid, the saturated vapor pressure P, the suction side pressure PS (absolute), the pressure in the discharge side container PZ, altitude, ambient temperature, whether the operation is intermittent or continuous, and whether the pump’s location is fixed or movable. The above information should be provided by the design institute or the user, or assisted by our sales staff in being submitted by the user; meanwhile, the centrifugal pump data sheet or water pump ordering inquiry form must be filled out carefully and thoroughly. Selection of Centrifugal Pumps Posted by: 2009-3-3 10:09:00 Centrifugal pumps generate pressure by using the centrifugal force created by the impeller rotating the fluid, thereby transporting the fluid. When selecting a centrifugal pump, it is necessary to determine the pump’s purpose and performance and choose the appropriate pump type. This choice starts with selecting the type and design of the pump. So, what principles should be used to choose a pump? What is the basis then? I. Principles for pump selection 1. Ensure that the type and performance of the selected pump meet the requirements of the process parameters such as flow rate, head, pressure, temperature, net positive suction head, and suction lift of the installation. 2. Mechanically, it features high reliability, low noise, and minimal vibration. 3. Economically, the total cost of equipment, operation, maintenance, and management should be considered to minimize expenses. 4. Centrifugal pumps feature high speed, small size, light weight, high efficiency, large flow rate, simple structure, pulse-free fluid delivery, stable performance, ease of operation, and convenient maintenance. Therefore, centrifugal pumps should be preferred as much as possible, except in the following cases: when metering is required, metering pumps should be used; when a very high head is needed along with a low flow rate, and no suitable centrifugal pump with a low flow rate but high head is available, reciprocating pumps can be chosen; vortex pumps can also be used if the requirement for cavitation is not high. When the head is very low and the flow rate is high, axial flow pumps and mixed-flow pumps can be used. When the medium viscosity is high (greater than 650–1000 mm2/s), a rotary pump or reciprocating pump (gear pump, screw pump) can be considered. If the medium contains 75% air, the flow rate is low and the viscosity is less than 37. At 4 mm2/s, a vortex pump can be selected. In situations where starting is frequent or pumping is inconvenient, pumps with self-priming capabilities should be used, such as self-priming centrifugal pumps, self-priming vortex pumps, and pneumatic (electric) diaphragm pumps. II. Criteria for Pump Selection The criteria for selecting a pump should be considered from five aspects, based on the process flow and water supply/distribution requirements: fluid flow rate, head of the system, properties of the fluid, pipeline layout, and operating conditions. 1. Flow rate is one of the key performance parameters for choosing a pump, as it directly affects the production capacity and transfer capacity of the entire system. If the process design in the design institute can calculate the normal, minimum, and maximum flow rates of the pump. When selecting a pump, the maximum flow rate should be taken as the basis, with consideration also given to the normal flow rate; in the absence of a maximum flow rate, 1 times the normal flow rate can generally be used. 1 times as the maximum flow rate. 2. The head required by the installation system is another important performance parameter for selecting a pump; generally, the head value should be increased by 5%–10% as a safety margin when making the selection. 3. Properties of the liquid, including the name of the liquid medium, its physical properties, chemical properties, and other characteristics. Physical properties include temperature, density, viscosity, the diameter of solid particles present in the medium, and the gas content; these factors are relevant to determining the system’s head pressure, the effective net positive suction head, and the appropriate type of pump. Chemical properties refer mainly to the chemical corrosiveness and toxicity of the liquid medium, and they serve as important criteria for selecting the material for the pump as well as the type of shaft seal to use. 4. The pipeline layout conditions of the plant system refer to data such as the liquid delivery height, distance, and direction; the lowest liquid level on the suction side and the highest liquid level on the discharge side; as well as details regarding pipe specifications, their lengths, materials, fitting specifications, and quantities. These are necessary for calculating the system head and verifying the net positive suction head. 5. There are many aspects related to operating conditions, such as the operating temperature of the liquid, the saturated vapor pressure P, the suction side pressure PS (absolute), the pressure in the discharge side container PZ, altitude, ambient temperature, whether the operation is intermittent or continuous, and whether the pump’s location is fixed or movable. III. Central air conditioning circulation pumps: By analyzing cases in central air conditioning system projects where failures occurred due to improper selection of the circulation pump head, this section emphasizes the importance of choosing an appropriate circulation pump head and proposes several methods for making such selections, which can serve as a reference for central air conditioning design. 1. Raising of the issue In central air conditioning systems, the circulation water pump transports chilled water in summer and hot water in winter to the air conditioning terminal units. Engineering design should select high-performance water pumps based on the water flow rate and system resistance of the air conditioning system. The HVAC design manuals provide detailed design calculation methods. The problem is that in actual engineering design, some engineers do not carry out design calculations based on the prescribed methods; instead, they rely on experience and fail to conduct thorough research on the system as well as new products such as certain air-conditioning equipment and components. As a result, the pumps chosen may not meet the required standards, which can lead to increased operating costs or even prevent the pumps from functioning properly. This issue warrants serious attention from those involved in air-conditioning design. 2. Theoretical analysis: The flow rate of water in the air conditioning system is determined by the load and the temperature difference between the supply and return water temperatures, while the system resistance is calculated through hydraulic calculations. A pump selected based on flow rate and resistance should operate in the high-efficiency zone, with its operating point being the intersection of the pump’s performance curve and the pipeline characteristic curve. In engineering, the pumps selected often experience two types of abnormal conditions. The steps, methods, and requirements for pump selection involve taking into account comprehensive technical and economic factors such as the investment and operating costs associated with the pump units and pumping stations, so as to ensure that the selection meets the principles of economy, safety, and suitability. Specifically, there are the following aspects: The pump must meet the requirements regarding flow rate and head; in other words, the operating point of the pump (the intersection of the device’s performance curve and the pump’s performance curve) should remain within the high-efficiency range as much as possible. This not only helps to save energy but also reduces the risk of damage to the pump’s components. The selected pump should be small in size, light in weight, and inexpensive, while also possessing good performance characteristics and high efficiency. It has excellent cavitation resistance, which not only reduces the excavation depth required for the pump house but also prevents cavitation in the water pumps, ensuring stable operation and a long service life. Pump stations are built using the selected water pumps, resulting in low project investment and low operating costs. 2. Selection steps a. List the basic data: Properties of the medium: name of the medium, specific gravity, viscosity, corrosivity, toxicity, etc. The particle diameter and concentration of the impurities contained in the medium. Medium temperature: (°C) Required flow rate. For general industrial pumps, the leakage in the piping system can be ignored in the process flow, but the impact of process changes on the flow rate must be taken into account. If agricultural pumps are used for water conveyance through open channels, leakage and evaporation rates must also be taken into account. Pressure: pressure in the water intake tank, pressure in the water discharge tank, pressure drop (head loss) in the piping system. Piping system data (pipe diameter, length, types and quantities of piping accessories, geometric parameters from the suction tank to the pressure tank, etc.). If necessary, the device characteristic curve should also be prepared. When designing and arranging pipes, the following points should be taken into consideration: A. Select the pipe diameter appropriately. A larger pipe diameter results in a lower flow velocity at the same flow rate, thereby reducing resistance losses; however, it increases costs. A smaller pipe diameter leads to a sharp increase in resistance losses, which in turn requires a pump with higher head pressure, more power to operate the pump, and thus higher costs and operating expenses. Therefore, a comprehensive consideration from both technical and economic perspectives is necessary. The discharge pipe and its fittings should be designed to withstand the maximum pressure they can handle. C. The piping layout should be arranged as straight as possible; accessories within the pipes should be minimized, and the length of the pipes should also be reduced as much as feasible. When bends are necessary, the radius of curvature of those bends should be 3 to 5 times the diameter of the pipe, with the angle being as large as possible, exceeding 90°. D. A valve (such as a ball valve or globe valve) and a check valve must be installed on the discharge side of the pump. Valves are used to adjust the operating point of the pump, while check valves prevent the pump from rotating in reverse when fluid flows backward, thus protecting the pump from water hammer effects. (When the liquid flows back, a huge reverse pressure is generated, which can damage the pump.) b. Determine flow rate and head. Flow rate determination: If the minimum, normal, and maximum flow rates are specified in the production process, the maximum flow rate should be taken into consideration. If only the normal flow rate is specified in the production process, a certain margin should be considered. For high-flow, low-head pumps with ns>100, the flow margin is set at 5, for ns

Centrifugal pump: prepare vulnerable components such as mechanical seals, bearings, oil seals, gaskets, etc. For gear pumps, prepare the front and rear shaft sleeves, mechanical seals or packing, gaskets, etc. For screw pumps, prepare the stator, rotor, etc

Regarding the spare parts for our company’s products, the following are required: 1. For fluoroplastic magnetic pump spare parts, corrosion-resistant and wear-resistant bearings and seals should be stocked. For the main components such as impellers, rotors, and isolation sleeves, a smaller quantity should be kept in order to save costs; this can be determined based on the operating conditions. It is also possible to keep spare pump heads as well； 2. For fluoroplastic centrifugal pumps, spare parts such as mechanical seals, sealing rings, and bearings should also be stocked. A smaller quantity of the main components like impellers and pump covers should be kept, depending on the conditions of operation; spare pump heads can also be available ； 3. For fluorine-lined self-priming pumps, spare parts such as mechanical seals, sealing rings, and bearings should be available; the main components – the fluorine-lined pump casing, front cover, and pump cover – should be provided depending on operating conditions, or spare pump heads can be used ； 4. Spare parts for mortar pumps include the pump casing, impeller, pump cover, fluororubber seals, gaskets, and bearings. Mortar pumps have high wear resistance but also wear down relatively quickly; therefore, it is advisable to keep more spare parts on hand or have a spare pump head available. The spare parts for other pumps are similar as well; there’s no need to list them all. Fluorinated valves and pipes are required only depending on the circumstances during use. Please point out any mistakes; thank you.

We have a considerable supply of spare parts: 1. Various pump accessories, including corrosion-resistant centrifugal pumps, clean water pumps, Roots vacuum pumps, mortar pumps, submersible pumps, magnetic pumps, double-suction split-case pumps, multi-stage pumps, gear pumps, slurry pumps, and ceramic pumps. Mechanical seal, pump casing, rear cover, gasket, pump shaft, impeller, coupling, and so on. 2. Spare parts for important rotating equipment such as centrifuges. 3. Glass-lined reactor spare parts. Stirring, mechanical seal, water jacket. 4. Electrical components, such as circuit breakers, relays, etc. 5. Various plastic pipe fittings and valves. 6. Various types of valve gaskets. 7. Various instruments such as platinum resistors, flow meters, etc. 8. Boiler accessories. 9. Daily-use hardware and miscellaneous items.

Rotating equipment: mechanical seals, engine oil; Others: gaskets, pressure gauges, etc.

Spares should be available for components such as the agitator in glass-lined reactors.

Thermoelectric 35T boilers: Instrumentation such as wear-resistant thermocouples, thermal resistors, solenoid valves, pressure gauges; electrical components such as circuit breakers, switching power supplies, etc.; mechanical parts such as pump bearings, mechanical seals, shock absorbers, elastic blocks, high-pressure valves, metal-wound gaskets, etc. For steam turbines, there are carbon brushes; for water treatment systems, there is polyaluminum chloride, acids, alkalis, ammonia, scale inhibitors, resins, etc. Centrifuges, air compressors, and nitrogen generators also include air filters, oil fine separators, oil filters, oxygen electrodes, and various types of oils

Critical equipment and its vulnerable components must be available; routine vulnerable parts such as the mechanical seals and packing for various pumps, as well as valve connections and filter elements in pipelines, need not be listed one by one