How to choose the right blower for the job

This is the content of "Handbook on how to choose the right blower for the job" in detail

Covers everything from basic factors to in-depth techniques. You can use it to make articles, teaching manuals, or work specifications.
In-depth guide: How to choose a blower (Blower Selection Guide)
Choosing a blower (Blower) or industrial fan It's not just about choosing the size of the inlet and outlet pipes. But the key is "matching".

The performance of the machine is compatible with The "resistance" of the system, if chosen incorrectly, may cause problems with not enough air, the motor burning out, or the noise exceeding the standard.
This is 5, an important step in selecting a professional blower.
1. Understand 3 main variables (The Big Three)
Before going to see the product catalog You must have 3 data like this on hand first:
1.1 Airflow / Capacity
is the amount of air that needs to be transported in one unit of time.
 * Popular units: CFM (cubic feet per minute), CMM (cubic meters per minute), or m^3/hr
 * Caution: Always allow for losses in the system approximately 10-20% from the actual calculated values.
1.2 Air pressure (Static Pressure - SP)
This is the most important value and is often overlooked. is the pressure required to Overcome friction in pipe systems, elbows, dust filter bags, or heaters.
 * Popular units: mm.Wg (millimeters of water), Pa (pascals), or in.Wg.
 * Principle: The longer the pipe, the more elbows, or the finer the filter, the higher the Static Pressure is required.
1.3 Temperature and air density (Temperature & Density)
Standard blowers are usually designed at Room Temperature (20-25°C) or Standard Air Density (1.2 kg/m^3).
 * If using hot air: The air will expand and become lighter (low density). Requires calculation of Correction Factor.

To select the correct motor size and propeller revolution. Otherwise you won't get enough air.

2. Choose the right impeller type (Impeller Types) for the job.
The impeller is the heart of the blower. Choosing the wrong type may cause damage to the propeller or consume unnecessary power.
A. Centrifugal Blower (centrifugal blower)
Most commonly used in the industry. Divided according to propeller characteristics as follows:
| Propeller type | Characteristics | Suitable for the job | Precautions |

Forward Curved (squirrel cage) | Frequent blades curve forward | Air conditioning work (HVAC), clean room air filling, quiet sound

| Do not use in dusty work. Because dust will stick to the propeller causing it to lose its balance. | Backward Curved (curved to the back) | High efficiency (High Eff.),

Consumes little electricity (Non-overloading) | General ventilation work, welding fume extraction, light dust | Slightly higher price than Forward type, but saves electricity in the long run. 
| Radial Blade (straight blade) | Thick blades, very strong, like a water wheel | Conveying materials such as sawdust, plastic pellets, rags

| Loud and less efficient than other types, but extremely durable. 

B. Roots Blower / Positive Displacement
 * Characteristics: Provides a constant amount of air. But the pressure can be very high.
 * Suitable for: wastewater treatment ponds (aeration), long-distance powder conveying work (Pneumatic Conveying)
C. Axial Fan (round tank fan)
 * Characteristics: Air flows through the motor shaft, providing high volume but low pressure.
 * Suitable for: cooling work in factories, sucking exhaust air out of buildings (not focused on sending through long pipes)

3. Select structural materials (Material Construction)
The environment in which the blower is installed determines the material:
 * Carbon Steel (painted black steel): for normal air work. No moisture or chemicals
 * Stainless Steel (SUS304 / SUS316): For food work (Food Grade), work with high humidity, or chemical vapors.
 * FRP / PVC / PP: for vacuuming up highly corrosive chemical vapors (Corrosive Fume Scrubber)
 * High Temp Construction: If the temperature exceeds 100^\circ C must have a shaft cooling kit (Cooling Wheel) and use heat-resistant ball bearings.

4. Drive Arrangement Transmission of power from the motor to the propeller Affects maintenance:
 * Direct Drive (direct drive):
    - Advantages: no belt maintenance required, compact, high power transmission efficiency.
    - Disadvantages: Can't adjust the speed (must use VSD), shock is sent directly to the motor.
 * Belt Drive (belt drive):
    - Advantages: Easy to adjust speed (RPM) by changing pulleys, absorbs vibrations well.
    - Disadvantages: The belt may become slack. Must set the tension regularly, wastes more installation space.

5. Check Performance Curve

 * Best Point: You should choose a blower that operates within the Peak Efficiency range of the graph (the point where the mountain is highest).
 * Avoid: Do not choose a blower at the rightmost operating point of the graph (Stalling zone) because it will cause the motor to work too hard and be loud.

Summary Checklist before ordering
 * Application: What is it used for? (Vacuuming, drying, conveying materials)
 * Airflow: How many CFM/CMM airflows are needed?
 * Static Pressure: What is the pressure loss in the system?
 * Temp & Condition: Temperature, humidity, or chemicals?
 * Power Source: Electricity used (380V 3Phase or 220V 1Phase)
 * Sound Level: Are there any noise limits? (If you have one, you must install a silencer.)