1. Air duct layout
The exhaust points of the dedusting system should not be too many to facilitate the resistance balance between the branches
The air duct shall be laid vertically or the angle between the air duct and the horizontal direction shall be greater than 45 degrees. If horizontal laying is required or the inclination angle is less than 30 degrees, measures shall be taken, such as increasing the flow.
The air duct of the ventilation system shall be circular or rectangular to ensure that it is clean and beautiful as far as possible under the premise of practical use.
In order to eliminate the exhaust system containing highly toxic substances, the length of the positive pressure pipe section shall be shortened as far as possible, and the positive pressure pipe section shall not pass through other rooms.
In order to remove moist gas or air duct containing steam, a gradient of not less than 0.005 shall be applied, and drainage measures shall be taken at the lowest point of air duct and at the bottom of fan.
Ventilation equipment, air duct and accessories shall be provided with corresponding anti-corrosion measures according to the environment, gas transmission, steam or dust corrosion, etc.
The air duct of ventilation system shall be provided with necessary side holes as required, and its position and quantity shall meet the inspection requirements.
2. Layout principle of dedusting pipeline
In addition to the general principles of the ventilation duct layout, there are also some special requirements:
(1) The air duct of dedusting system shall be round steel air duct, and its joints and joints shall be tight.
(2) The air duct shall be installed vertically or obliquely. The angle between inclined installation and horizontal plane shall be greater than 45 °. The pipe section with small gradient or horizontal laying shall be shortened as far as possible, and measures shall be taken to prevent dust accumulation.
(3) The branch pipe is inserted from the top or side of the main pipe, and the included angle of the tee pipe is 15 ° - 45 °.
(4) A closed cleaning hole is arranged near the special-shaped pipe fitting, which is easy to accumulate dust.
(5) The radius of curvature at the turning of dedusting pipeline is r = 1.5-3.0d. If the radius of curvature is not allowed to be large, the guide vane shall be installed in the elbow.
3. Selection of air pipe
(1) Common section shape:
Rectangle: convenient for construction and decoration; parts are easy to manufacture.
——Commonly used in air conditioning system
Circle: low resistance; low material and high strength; easy to make piping.
——High speed air duct for ventilation system and air conditioning
Other shapes: as needed.
4. Tube Standardization:
(1) In the uniform specification for ventilation pipe, the diameter of circular pipe is the outer diameter, and the size of rectangular section is the outer diameter, that is, the size includes the corresponding material thickness.
(2) In order to meet the demand of resistance balance, there are many pipe diameter specifications of dedusting pipe and airtight pipe.
(3) The pipeline section size (diameter, side length) adopts R20 series, that is, the pipeline section size is prepared by a multiple of 1.12 larger than the common ratio.