It is a rectangular parallelepiped that carries the air to be distributed over the areas to be conditioned in calculated quantities that are controlled by the area of the duct section that passes inside the air….
This means that if you reduce the height and width of the duct, the amount of air coming out of it will decrease because you are suffocating the air and forcing it to pass through the larger path.
Its function:
The body's arteries carry blood to all parts of the body, and the air ducts carry air and distribute it to all parts of the building.
Air paths have several classifications, including:
1- Classification according to speed:
* Low speed up to 10 meters per second.
* High speed and be higher than 10 meters per second.
2- Classification according to pressure:
1- Low pressure from zero to 50 Pa.
2- Medium pressure from 50 Pa to 150 Pa.
3- High pressure from 150 to 250 Pa.
* Q: What are air ducts made of?
* Air ducts are made of:
1- Galvanized steel.
* What is meant by iron sheet is one of the most famous types of materials used for the manufacture of AC DUCTS.
2- The stainless steel of this type is used in the following places:
1- Moist air expelled from swimming pools and saunas for the first 5 meters after the air intake outlet.
2- Moist air expelled from kitchen appliances.
3- Air ducts carrying combustion products.
4- Air ducts exposed to fumes of corrosive chemicals.
5- Ducts connected to a humidifier for a distance of 1 meter against the direction of the air and 3 meters against the direction of the air.
5- Ducts connected to a humidifier for a distance of 1 meter against the direction of the air and 3 meters against the direction of the air.
It shall be circular, rectangular or square in shape, and its walls shall be at least 25 mm thick
* Note: It is not allowed to install air ducts made of glass wool in machine rooms or in places where the ducts are exposed to the outside atmosphere.
4- Aluminum:
* Air ducts are made of aluminum because it is lightweight and easy to install
Q: What are the types of ducts?
1- Rectangular Duct
1- Rectangular Duct
* Connects the branches and the rising riser
* Connects between terminal units and mixing units
* Connects between air inlets and air outlets and inlets
Q: What are flexible air ducts made of?
1- It is made of a flexible material tied to a flexible metal, covered with glass wool and coated with zinc.
* The flexible duct is used when the temperature does not exceed 80 degrees Celsius and the length of the flexible duct does not exceed 5 meters.
* It should not pass through walls and closed skylights so that it is easy to reach because it breaks after a period of use and is not placed in the walls until it is easy to remove it when needed. .
3- Pre-insulated duct
It is a duct made of a layer of foam and around it from the inside and outside with a layer of coarse aluminum with a thickness of not less than 80 microns, so the thickness of the foam with aluminum is 21 mm.
Features:
1- Easy to install compared to Gi sheet
Gi=Galvanised insulated sheet steel
2- The price is cheap for the saj.
2- The price is cheap for the saj.
4- The foam inside the pre-insulated duct is characterized by its low coefficient of thermal conductivity (0.0212w/mk), while the glass wool used to insulate the sheet has a higher coefficient of thermal conductivity (0.38w/mk).
5- The foam inside the pre-insulated duct is characterized by being resistant to fire and toxic gases compared to glass wool.
6- Foam is distinguished by allowing water vapor to pass through, so it is suitable for wet places.
7- Resistant to corrosion and rust
8- It is easy to wash and paint
9- Environmentally friendly.
10- It does not require that you do any cladding in the form of the letter X in the places exposed to the sun in which the pre-insulated duct is installed.
Noticeable :
Foam is injected inside the aluminum plates, meaning that the aluminum plates are first installed in the form of a rectangle and a space is left between them, then the foam is injected inside the aluminum plates.
4- Spiral duct
* It is a path of air, but it takes the form of a spiral, and it is of the following types:
1- Duct (air path) spiral circular.
2- Flat helical duct (air path).
Duct manufacturing steps
1- The lengths of the air ducts are lifted from the diagram and arranged in a table with their quantities
2- The iron sheet is detailed and cut according to the sizes in the table, and when the iron is detailed, we add 3 cm from each side to make the duct so that the ducts are locked together.
3- The letter x is made in the sheet for each of the four sides of the surfaces that need strengthening, so this tax will be a nerve... The short path does not need a tax because its short length gives it strength.
4- The duct is detailed by closing the duct
5- Then the insulator is detailed for each piece of the duct, and we talked about it in detail in a topic on the site about isolating the air paths. 7- The acoustic sound insulator is detailed for the pieces adjacent to the machine with a length of 3 meters from inside the duct and installed with the clips that you install in the duct