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气力输送设计的重要参数

Important parameters for pneumatic conveying design

When designing a positive pressure pneumatic conveying device, it is necessary to first understand and study the properties and particle shape of the conveyed material, conveying components, on-site conditions, etc. Based on this, fully utilize the advantages of pneumatic conveying, and correctly select the type of pneumatic conveying to improve production efficiency. 1. The properties and particle shape of the conveyed material. The average particle size of the material is often taken as the calculated particle size, and the distribution of material particle size should be understood. The fluidity of materials

气力输送系统的设计

Design of pneumatic conveying system

When designing a pneumatic conveying system, there are many factors to consider, including material characteristics, conveying capacity, conveying distance, installation location, etc. Below, Juheng's editor will divide them into 9 categories for detailed explanation. 1. The physical and chemical properties of materials mainly include product name, average particle size and particle size distribution, particle shape and surface flowability, adhesion and cohesiveness, bulk density, density, stacking angle and friction angle, moisture content (mass fraction of water), moisture and deliquescence, hardness and grinding

气力输送吸嘴的设计

Design of pneumatic conveying suction nozzle

When sucking materials, the design of the suction nozzle is also particularly important. Suction nozzles can be divided into rotary suction nozzles and angular suction nozzles. Rotary suction nozzles are generally used for materials with poor fluidity, while angular suction nozzles are generally used for cabins and carriages, with joints connected to circular cross-section feeding pipes. 1. The rotary nozzle suction pneumatic conveying device is used to suck and transport materials with poor fluidity, such as coal and crushed coal, sand, cement, fertilizer, bauxite, soybean residue, corn residue and crushed soybean cake, sawdust, etc

气力输送吸嘴的注意点

Attention points for pneumatic conveying suction nozzle

When choosing a negative pressure pneumatic conveying system, attention should be paid to the design of the suction nozzle, as the corresponding pressure for different materials is different. Through continuous research by Juheng, the following summary has been made: 1) It is necessary to adjust the end face gap between the inner and outer pipes correctly. According to a large number of experiments on the suction of rice by inland grain suction machines, when the depth of the suction nozzle inserted into the material layer is maintained at 300-400mm, the end face gap s value changes between 2-18mm. The measured s value is consistent with the effective productivity of the grain suction machine

风量对气力输送的影响

The influence of air volume on pneumatic conveying

With the change of air volume in pneumatic conveying, the conveying capacity of pneumatic conveying will also be affected. According to Juheng's continuous experiments, the following summary can be drawn: 1. The reduction effect of increasing air volume is compared with increasing air volume by 60%. There are two methods to increase air volume: switching to a large fan or increasing the speed of the original fan. If a fan with a 60% increase in air volume and a supply pressure of 60kPa is used instead, it will be changed to point B in Figure 2. Obviously, the conveying capacity has decreased to 2.7/h, reducing

气力输送的条件

Conditions for pneumatic conveying

The conditions for pneumatic conveying include the minimum pneumatic conveying wind speed, the characteristics of pneumatic conveying, and the characteristics of the fan. To achieve the conveying wind speed under the lowest pressure loss, it is necessary to understand the relationship between air mass flow rate and pressure difference, the relationship between air mass flow rate and conveying capacity, and the relationship between air mass flow rate and conveying wind speed. Below, let Juheng's editor introduce the impact of material and pneumatic conveying conditions on pneumatic conveying. 1. The minimum air speed for pneumatic conveying is

气力输送的操作优化

Optimization of pneumatic conveying operation

At present, there is a considerable level of understanding and application of the motion laws of continuous fluids (gases or liquids). The flow of solid particles in gas-solid two-phase flow belongs to discontinuity, as discontinuity is the main characteristic of powder (particle group). How to accurately describe the discontinuous two-phase flow of solid and gas is a difficult problem in the development of pneumatic conveying engineering. Scientifically speaking. While applying the three-dimensional analysis and modeling methods mentioned above, it is also necessary to avoid

气力输送中实际流化过程

Actual fluidization process in pneumatic conveying

The previous article was about the ideal fluidization process, where the relationship curve between pressure drop and gas velocity is very regular. The relationship curve between pressure drop and gas velocity in the actual fluidization process of pneumatic conveying is shown in Figure 1. Figure 11. Fluidization experimental process

气力输送流态化过程与流体特性

The fluidization process and fluid characteristics of pneumatic conveying

Pneumatic conveying fluidization (referred to as fluidization) is a process that involves bringing a solid particle layer (bed) into contact with gas moving through it, transforming it into a fluid like state, thereby achieving favorable process requirements for particle material flow, chemical reactions, and heat exchange. 1、 Ideal fluidization process and fluid like characteristics: 1. The ideal fluidization process is equipped with a cylindrical container and a porous plate (sieve plate or gas distribution plate) installed at the bottom. Stacking a layer of granular material (i.e. bed layer) on a porous plate

气力输送中颗粒群的悬浮速度

Suspension velocity of particle groups in pneumatic conveying

In the gas-solid two-phase flow of pneumatic conveying, the materials generally conveyed are mostly irregularly shaped particle groups. 1. The influence of irregularly shaped particles on suspension velocity: Among materials of the same weight, spherical particles have the highest suspension velocity, while other irregularly shaped particles have correspondingly lower suspension velocities. This is because the resistance coefficient of irregularly shaped particles is greater than that of spherical particles. Even for the same irregularly shaped particle, due to its orientation relative to the airflow

气力输送中不规则形状颗粒群的悬浮速度

Suspension velocity of irregularly shaped particle groups in pneumatic conveying

In the gas-solid two-phase flow of pneumatic conveying, the materials generally conveyed are mostly irregularly shaped particle groups. 1. The influence of irregularly shaped particles on suspension velocity: Among materials of the same weight, spherical particles have the highest suspension velocity, while irregularly shaped particles have correspondingly lower suspension velocities. This is because the resistance coefficient of irregularly shaped particles is greater than that of spherical particles. Even for the same irregularly shaped particle, due to its different orientations relative to the airflow

气力输送的防爆措施

Explosion proof measures for pneumatic conveying

Dust explosion is very dangerous, so how to prevent the danger in pneumatic conveying? Let me take you to understand: 1. The existence or appearance of ignition sources is the most direct cause of dust explosion. According to statistical data analysis, the types of ignition sources and their probability of occurrence, and reserving sufficient release port (door or membrane) area on the equipment can timely suppress dust explosion. As shown in the figure, at a certain rate of pressure increase, the release area depends on the container itself

在粉体气力输送时，要了解粉体爆炸的特性

During powder pneumatic conveying, it is important to understand the characteristics of powder explosion

During powder transportation, the suspended dust in the air must have sufficient oxygen and a suitable range of dust concentration in order to trigger dust explosions and ignition temperature conditions: ① Sufficient oxygen is required. ② The appropriate range of dust concentration, that is, the spacing between dust particles, can ensure that the flame can flow freely and extend to the surface of adjacent dust particles, without causing local oxygen deficiency due to the dust particles being too close to each other. ③ In order to maintain the ignition temperature of dust

气力输送中如何防止静电

How to prevent static electricity in pneumatic conveying

In pneumatic conveying, the harm of static electricity is very significant. Static electricity may cause material adhesion and dust explosion. Therefore, when designing pneumatic conveying, it is important to pay great attention to static electricity in pneumatic conveying. So, how to prevent static electricity? Let Juheng's editor understand for you below. 1. The disasters caused by electrostatic discharge of charged objects are due to their discharge, which forms an ignition source, which is one of the necessary conditions for dust explosions. Electrostatic discharge refers to

气力输送中带电粘附与临界粒径

Electric adhesion and critical particle size in pneumatic conveying

In pneumatic conveying, static electricity can cause adhesion. In the case of relatively fine powder particles, charging will always be accompanied by adhesion, while relatively coarse powder particles can be used as a measure to prevent adhesion, as shown in Figure 1. As the particle size increases, the porosity will decrease and eventually tend towards a constant value. This means that it is indirectly affected by adhesive force. The particle size at this constant value is called the critical particle size. Figure 1

气力输送中粉体的带电量如何计算的

How to calculate the charged amount of powder in pneumatic conveying

In pneumatic conveying, the friction of powder in the pipeline will carry static electricity, and materials with static electricity are prone to clumping. In order to better understand these material conveying methods, it is necessary to know the static electricity of materials in the pipeline. Therefore, based on these, let the editor of Shandong Juheng introduce the charged amount of powder in pneumatic conveying. The charged amount of powder 1. The measurement of the charged amount of powder is shown in Figure 1. The powder particles flowing through fall between the plates, and at the same time, the camera (shutter speed of 1/1

气力输送工程要具备那些知识

What knowledge is required for pneumatic conveying engineering

The sustained development of science and technology is based on two main factors. Firstly, the deepening and improvement of the main disciplines themselves. There are more than 70 main disciplines, such as mechanical engineering, mechanics, chemical engineering, etc., among which there are fundamental and applied ones; Another is that the main discipline has spawned thousands of branch disciplines, especially further forming many technological frontiers in the development of modern science and technology. Pneumatic conveying is an interdisciplinary product of several main disciplines and branch disciplines, as shown in Figure 1. As shown in the figure

气力输送中静电发生机理

Mechanism of static electricity generation in pneumatic conveying

If materials stick together in pneumatic conveying, it may cause blockage, so static electricity in pneumatic conveying should be given special attention. 1、 The mechanism of static electricity generation is based on the phenomenon of excess positive or negative charges on an object, and the excess charge is called static electricity. Static electricity is mainly caused by the contact or separation of two objects. Accumulate, move, and even disappear according to the conductivity of the object. Insulators with a general conductivity below 10-8s/m will

气力输送中影响粘附的因素

Factors affecting adhesion in pneumatic conveying

The factors affecting adhesion in pneumatic conveying include particle size, porosity and moisture, airflow velocity and roughness avoidance, flow field forces, and collision forces of obstacles. 1. The relationship between particle size and adhesion force. According to experience, the finer the powder, the easier it is to adhere. This is due to the increased adhesion force per unit mass and mechanical interaction effects when particles are small. 2. The porosity and moisture can be measured using the fracture method. It can be observed that a decrease in porosity and an increase in moisture will both increase

分析三种气力输送方式的工作原理

Analyze the working principles of three types of pneumatic conveying methods

According to the pressure state, it can be divided into suction pneumatic conveying device, compression pneumatic conveying device, and hybrid pneumatic conveying device. Below, we will analyze their specific working processes. Suction type pneumatic conveying device is a device that uses Roots blower or negative pressure Roots blower as the air source equipment. The components of the feeding device are mostly suction nozzles, induction type feeders, etc. The most common process layout system is shown in Figure 1. The gas source equipment is installed at the end of the system, and when the fan

气力输送的发展历史

The development history of pneumatic conveying

After gaining inspiration from the natural phenomenon of wind blowing stones and dust, as well as the common sucking phenomenon in daily life, people envisioned using airflow to transport materials in pipelines. Based on this idea, as early as 1810, Medhurst in England proposed a plan to use pipelines for pneumatic transportation of mail. Therefore, pneumatic conveying technology began with the cylindrical conveying of finished items. Decades later, pneumatic conveying began to be used for unloading bulk materials such as grains, cotton, and sand, and the first floating