2013年7月21日星期日

Two properties of bulk materials and verification elements



Electrical properties
1. Static electricity
Static electricity is an electrical potential of the material obtained, causing adhesion or attachment, and affect the material flow. When through the hopper or belt conveyor

discharge, sieving or dry granular materials are mixed, in close contact with these materials suddenly separated, the particles may induce electrostatic potential. Non-

conductive solids such as plastics are particularly prone to the above problems.
The size of static electricity by meter measurements. Design by equipment grounding, controlling the movement of atmospheric humidity and the appropriate methods to prevent

electrostatic material harm. Power Roller Conveyor
Typically, non-metallic oxides and acid generation, such as carbon, sulfur, silica, salt, starch, etc. can be positively charged. Metals and their oxides, such as iron oxide,

magnesium oxide, soda ash, aluminum, alumina, zinc oxide and zinc oxide can be negatively charged.
Take the following measures to reduce electrostatic effect: to make the material sufficiently grounded; controlled humidity to prevent moisture on the material impact; using

antistatic medium; using energy and materials compatible additives; changing the flow rate. Higher flow rates will lead to an uneven distribution of charge; change conveyors

method; changing device material, easy to charge elimination and so on.
2. Magnetic
Refers to a solid magnetic performance can be magnetically attracted. Magnetic force can be used to separate the iron from the solid, but also used to transport materials.  Flexible Roller Conveyor
3. Conductivity
The conductive material is capable of transmitting electric current in nature. When processing a material having such properties, the ground is necessary.
Temperature of
1. Mp
The melting point is a solid and a liquid which has a softening temperature. Some of the material when it reaches this temperature it is damaged, or there will be in a fluid

state, corrosive or toxic. Temperature control and alarm system can be used to avoid this hazard.
2. Freeze
Wet material can cause the ice to freeze bond impede flow. This phenomenon usually occurs during the cold season in storage bunkers or rail vehicle, which prevents tools are:

use of insulation material silo silo wall insulation or heating jacket used to control the heating temperature; using a small amount of additive is mixed with the storage of

materials, to lower the freezing point.
3. Temperature
Because such material is subjected to temperature changes and other physical properties of crystals changes, but also to appear caking cracking. Change of temperature and other

effects are not always clear lumps, due to the small amount of water, and in the process the presence of other vapor, will bring the problem of liquidity. Therefore, in the

operation of a genuinely representative sample sampling is important.
Summary
Section bulk solids with a variety of properties and a number of related properties. In the design of a variety of bulk solids storage system, you must first be investigated.

Typically, before you start designing the material given to verify the following:
To get the material bulk density, grain size, largest block of data as well as the shape of the solid; obtained angle of repose of the material and the sliding angle data;

determine whether the material containing dust or toxic or explosive; to understand the temperature or humidity on the flow properties of materials have any effect; according to

materials of construction material being processed and the extent of corrosion abrasive consider the need for the use of special construction materials or demonstration of its

correctness; understand the material is bonded or free-flowing, wet or dry, combustible or decomposable; materials can be caused due to electrostatic adhesion and adhesion.
The lack of any one of these various indicators of data, will seriously affect the system of the selected transport machinery, silos and feeding equipment in normal operation.

If you really can not get the data, it is best to run in all types of materials can be processed to obtain the actual operation unit test data. Operational test and ascertain

the effectiveness of these devices are required equipment manufacturer collaboration. In the United States generally use this method to solve such unknown and the lack of

experimental data by engineering problems.

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