Fans are equipment for moving air, gases and their mixtures with solid small particles inside a duct system or at any object by creating a pressure difference between the entry point and the discharge point of the ventilation unit. The pressure changes due to the action of the centrifugal force of the transported medium moving inside the fan casing from the center to the edges.
The use of forced draft fans
The VDN fan is intended for gas or air environments that are not explosive and do not contain sticky particles and fiber materials. The maximum permissible concentration of dust particles is 0.1 mg / m 3 . And the temperature of the transported medium should not be higher than 200 ° C.
These fans use:
- In boiler rooms. Air is introduced into the furnace to stimulate combustion, and combustion products are removed from the boiler.
- In thermal power plants.
- On various technological lines.
- As part of ventilation systems and air conditioning systems.
- In smoke removal systems: both for organizing backwater and for removing air.
How to understand the labeling
Numeric and letter designations in fan markings say a lot about it.
- The letters determine the type of machine: smoke exhaust - D, blower fan - VD (vanes are bent forward), N - vanes bent back.
- Numbers - wheel diameter in decimeters.
So, the marking "fan VDN-10" means that it is a blower fan with impeller blades bent back and a diameter equal to one meter.
Terms of Use
The VDN fan must be operated in the temperature range between -30 ° C and + 40 ° C. It is designed for a long period of work in temperate zones. However, it is possible to manufacture equipment for working in more severe conditions by placing a special order. Fans can work both inside buildings and on the street.
Place to install
The place for installing the fan is prepared based on the design documentation. It is made horizontal, taking into account the mass of the installed equipment. The undercarriage with an electric motor and the fan casing are mounted either directly on the foundation or on a vibration base.
Design Features of VDN Fan
The design is similar to other centrifugal fans. The main parts:
- Spiral steel casing with horizontal connector and access door to the fan impeller. The stiffeners from the channels reinforce the metal "snails".
- Fan wheel, consisting of a hub and an impeller with 16 vanes, bent back.
- The funnel is soaking up.
- Guide axial apparatus.
- Installation frame.
Fans with backward curved blades are less noisy, they have a wider range in air consumption, and there are no unstable operation zones. Their efficiency coefficient is the highest among all centrifugal fans. The payment for these advantages is an increase in weight and size (compared to equipment with forward curved blades), as well as the inability to operate in "dirty" rooms (where there are a lot of impurities and dust in the air). With this design of the impeller, dust particles settle on it, causing imbalance and vibration.
The VDN fan can be manufactured with the position of the LO or PO housing, which means the direction of rotation of the impeller is left or right. To determine the type of rotation, you need to look at the wheel from the side of the electric motor. With right rotation, it moves clockwise. With the left - counterclockwise.
VDN-10 fans are produced in three versions:
- Version 1. The fan wheel is seated on the motor shaft.
- Version 3. The fan wheel is connected to the engine through the bearing assembly.
- Version 5. The fan wheel is mounted on the shaft of the bearing assembly, which is connected to the electric motor by means of a V-belt drive .
Specifications
The table below shows the technical characteristics of the VDN-10 blower fan. Total pressure (Pa), air capacity (m3 / h), consumed electric power (kW) are determined for the fan to operate when the axial guide vane is open. The characteristic point passes through max efficiency (83%). Atmospheric pressure is assumed to be normal, temperature +30 , air density - 1.18 kg / m 3 .
VDN-10 is available with two types of engines with a capacity of eleven or thirty kW. For this reason, fans with the same wheel diameter (with different engine power) have a 50% performance difference and a pressure of more than 100%.
The table below shows the characteristics of the VDN-10 fan.
Aerodynamic characteristics of VDN-10
On the diagram you can see the aerodynamic characteristics of VDN. The following notation is used: P - total pressure, Q - productivity, η - efficiency, N - power.
Fan transportation
The VDN-10 fan has a large mass and large overall dimensions. Therefore, it is important to arrange transportation correctly so as not to damage expensive equipment. It is necessary to order packaging and crate. Ask the sender to check the consolidation of the cargo and, if possible, make a photo-fixation of the loading process. Thanks to these simple measures, financial losses can be avoided.