There are many models of various pumps, they all have different technical parameters, in the purchase, to be combined with their own conditions of use and reference to product technical parameters, choose the pump for your own use. Now to introduce the selection of the main rotor pump points. Cam rotor pump cam rotor pump selection points First, the basic parameters based on 1. Flow is one of the important performance pump election data, which is directly related to the entire plant's production capacity and delivery capacity. Such as the design process can be calculated in the pump normal, minimum, maximum three kinds of flow. Select the pump, based on the maximum flow, taking into account the normal flow, in the absence of maximum flow, usually desirable 1.1 times the normal flow as the maximum flow. 2. Installation system required lift is another important performance pump election performance data, generally to enlarge the 5% to 10% head lift to choose. 3. Liquid properties, including the name of the liquid medium, physical properties, chemical properties and other properties, the physical properties of temperature c density d, viscosity u, medium particle diameter and gas content, etc., which involves the system lift, effective gas Erosion margin calculation and the type of suitable pump: Chemical nature, mainly refers to the liquid medium chemical corrosion and toxicity, is the selection of pump materials and choose an important basis for the type of shaft seal. 4. The piping system installation conditions refers to the liquid from the height of the liquid from the liquid to the suction side suction side of the lowest level, the discharge side of the highest level of some data and pipeline specifications and the length of the material, pipe specifications, the number , Etc., in order to carry out the Department of combing head calculation and NPSH check. 5. There are many operating conditions, such as liquid operation T saturated steam P, suction side pressure PS (absolute), discharge side vessel pressure PZ, altitude, ambient temperature operation is intermittent or continuous, the pump position is fixed Or removable. Second, other factors affect the general industrial pumps in the process can be ignored in the pipeline leakage, but must consider the impact of process changes on the flow. Agricultural pumps if the use of open channel water, but also must consider the leakage and evaporation. Pressure: suction tank pressure, drainage tank pressure, pressure differential in the piping system (head loss). Pipeline system data (diameter, length, type and number of pipe attachments, geometry of sump to sump). The device characteristics should also be made if necessary. Third, the impact of pipelines in the design and layout of the pipeline, should note the following: A. Reasonable choice of pipe diameter, pipe diameter, the same flow, the flow velocity is small, the resistance loss is small, but the price is high, the pipe diameter is small, will Resulting in a sharp increase in resistance loss, increasing the head lift of the selected pump, increasing the belt power, and increasing the cost and operating cost. Therefore, it should be considered technically and economically. B. Exhaust pipe and fittings should be considered to withstand the maximum pressure. C. Pipe layout should be arranged as straight pipe as far as possible to minimize the attachment in the pipe and minimize the length of the pipe, you must turn when bending the elbow bend radius should be 3 to 5 times the pipe diameter, the angle is greater than 90 ℃. D. The discharge side of the pump must be equipped with a valve (ball valve or globe valve, etc.) and a check valve. The valve is used to adjust the operating conditions of the pump. The check valve prevents the pump from reversing when the fluid is flowing backwards and prevents the pump from hitting the water hammer. (When the liquid backflow, will have a huge reverse pressure, so that the pump damage) Fourth, the impact of flow head to determine the flow A. If the production process has been given the smallest, normal, maximum flow, should be considered the maximum flow. B. If the production process only gives normal flow, should consider leaving a certain margin. For ns100 large flow low-lift pump, take 5% of the flow margin, the ns50 low-flow high-lift pump, the flow margin of 10%, 50 ≤ ns ≤ 100 pump, the flow margin also take 5% of the quality Poor pump performance and poor operating conditions, flow margin should be taken 10%. C. If the basic data only to the weight flow, should be converted into volume flow. Fifth, the impact of temperature High-temperature medium transport on the pump structure, materials and auxiliary systems put forward higher requirements, the following talk about the different temperature changes on the cooling requirements and the company applies to the pump: 1. For temperatures below 120 ℃ Of the media, usually do not set a special cooling system, use more of their own medium to lubricate and cool. DFL (W) H chemical pump, DFL (W) PH shield chemical pump (class H should be used for shielded motor over 90 ℃); DFCZ common type and IH chemical pump can make the temperature Up to 140 ℃ ~ 160 ℃; IHF lined with fluorine pump up to a maximum temperature of 200 ℃; only CQB ordinary magnetic pump temperature does not exceed 100 ℃. It is worth mentioning that for the easy-to-crystallize or media containing particles should be equipped with a sealing surface flushing pipe (design have left interface). 2. For media above 120 ° C and within 300 ° C, a cooling chamber is normally to be provided on the pump cover and the seal chamber is also to be filled with coolant (to be fitted with a double-ended mechanical seal). When coolant is not allowed to penetrate the medium , It should be taken after the cooling medium itself access (through a simple heat exchanger). The company has DFCZ chemical process pump, GRG high temperature pipeline pump and HPK hot water circulating pump (under development) to choose from, the other CQB-G high temperature magnetic pump can be used within 280 ℃ high temperature medium. 3 for more than 300 ℃ high temperature medium, not only need to cool the pump head part, the suspension bearing chamber should also be equipped with cooling system, the pump structure is generally the central support form, the mechanical seal is best to use metal bellows type, but the price is high The price is more than 10 times the ordinary mechanical seal). Sixth, the impact of sealing Leakage is the eternal pursuit of chemical equipment, it is this requirement has led to the growing use of magnetic pumps and shielded pumps. However, there is still a long way to go without leakage, such as the life span of the magnetic pump isolation sleeve and shielding pump shielding sleeve, the material pitting problem, the reliability of static sealing, and the like. Now some basic aspects of sealing a brief introduction. 1. Sealing form, for static sealing, usually only two forms of seals and seals, and O-ring seals are the most widely used; for dynamic seals, chemical pumps rarely use packing seal to mechanical seal as The main, mechanical seal and a single and double-ended, balanced and unbalanced type, balanced type for high pressure medium seal (usually refers to the pressure greater than 1.0MPa), double-sided machine seal is mainly used for high temperature, easy crystallization, Viscous, containing particles and toxic volatile medium, double-ended machine seal should be injected into the sealed chamber isolation fluid, the pressure is generally higher than the medium pressure 0.07 ~ 0.1MPa. 2. Sealing material, chemical pump Static sealing materials generally use fluoroelastomers, special circumstances before the use of PTFE material; mechanical seal ring static material configuration is more critical, not cemented carbide on the best cemented carbide, the price is high On the one hand, the difference between the two hardness is not reasonable, so it is best to distinguish between media characteristics. Seven, the viscosity of the medium Viscosity of the pump performance is great, when the viscosity increases, the pump lift curve decreased, the working conditions of the head and flow are decreased, while the power will rise, and thus reduce the efficiency . General parameters on the sample are the performance of the transport of water, when the transport of viscous media should be converted (different viscosity correction factor can be found in the relevant conversion chart). For the viscosity of the pulp, paste and viscous liquid delivery, the proposed selection of screw pump, DFGG single screw pump medium viscosity up to 1000000cst. Further Reading: pump valve pipe fittings Exhibition 2016 Exhibition of Information Industry, Internet (Xiamen) Technology Co., Ltd. Author: Asian pumps Network Editor: Yao Xiaoxia (QQ / micro letter: 2355962924) http://beng.liuti.cn/ (Hotline : 400-6030-811)