ข้อดี-ข้อเสียของแต่ละตัวควบคุมของเครื่องอัดลมเดี่ยว
เราได้เรียนรู้เกี่ยวกับตัวควบคุม 6 อย่างของปั๊มลมเครื่องเดียวไปแล้วในบทความก่อน คุณจะตัดสินใจเลือกใช้ตัวควบคุมไหนกับปั๊มลมของคุณ ลองมาดูว่ามีข้อดีข้อเสียแตกต่างกันอย่างไรบ้างสำหรับตัวควบคุมที่เป็นพื้นฐานในเครื่องอัดลม (ปั๊มลม) เดี่ยว
Previously we discussed The 6 Types of Basic Individual Compressor Controls to learn about the differences, but how do you determine which controls you would want for your compressor? To help with this decision here are few pros and cons of the basic air compressor controls:
Start/Stops
Pros
- Simple control using only a pressure switch
- Motor and compressor operate only when needed, which saves energy
- Good for small compressors that are 25 HP or less (depending on application)
Cons
- Frequent starting wears down motor and compressor
- The pressure setting to stop must be higher than required system pressure to build storage. This may increase energy use.
- Loss of pressure control in the range of 35 psi
- Limited to small compressors
Load/Unload
Pros
- Motor compressor runs continuously which reduces wear and tear associated with too many frequent motor starts
- Tighter range of pressure (approx 10 psi)
- Provides adequate storage and offers energy-efficient control of rotary screw, reciprocating and some centrifugal compressors
Cons
- If applied incorrectly short cycles cause premature wear and tear. There is minimal or no power savings on lubricant-injected rotary screw compressors
- There needs to be proper blow down time and the storage capacity required for lubricant-injected rotary compressors to achieve energy savings and prevent lubricant foaming
- Requires over-pressurizing to maintain minimum system pressure
Modulating
Pros
- The motor and compressor run continuously reducing wear
- Tighter range of pressure control (10 PSI)
- Steady progressive capacity control that matches demand
Cons
- Pressure ratios increase as inlet pressure is throttled
- Inefficient at lower loads(lubricant-injected rotary compressors limited to 40-60% capacity; centrifugal compressors limited by potential surge and may require discharge blow off)
Dual/Auto Dual
Pros
- Combines features of modulating, load/unload. and start/stop
- Shuts down compressors when unloaded for pre-set duration which in turn saves energy
- Better selects operation mode for small reciprocating compressors
Cons
- Makes the control complex
- The Over-run timer must be set to limit premature starting and stopping
Variable Displacement
Pros
- Energy-efficient control scheme that gets down to 50% of capacity
- Matches displacement to demand without reducing inlet pressure or increasing ratios of compression
Cons
- Makes the control complex
- High initial cost
- Only available for 50 HP+ compressors
Variable Speed
Pros
- Energy-efficient and precise control
- Various rotating speeds and giving more displacement and power. These are directly proportional to speed rotation
Cons
- Makes the control complex
- High initial cost
- Reduced full load efficiency
- Efficiency of rotary screw compressor ends drop at lower or higher speeds
