技術資料-選用空壓機的十大考量因素 - 技術資料


在建置壓縮空氣系統時，除了購置費用以外，如何節約高額的電費開支、延長空壓機的壽命、平穩供氣壓力及降低環境噪音與污染？一直是用戶殷切期待解決的問題。而如何在設置的初期正確的選用空壓機扮演著關鍵性的因素。列舉選用空壓機的十大考量因素如下：

1.	壓縮空氣的用途：
	絕大多數的使用者在選購空壓機時，鮮少考慮壓縮空氣用，例如動力傳輸用或是儀錶、設備冷卻及偵測使用，建立壓力應該是不同。許多工廠規劃者一開始就建立相同壓力替代使用，導致每年浪費系統電力。

2.	壓力：
	應該先了解各個用氣端的最高與最低使用壓力，再加上輸送管路及淨化系中必要壓降與空壓機空重車的壓力範圍，就可決定空壓機的額定排氣壓力。
	一般管路的損失約為0.5 kg/cm²，壓縮空氣通常須經清淨化系統處理，透過管路進行熱交換的乾燥，或透過過濾器，進行清淨的程序，都會產生壓力降，大概是 0.3~0.5 kg/cm²(過濾器＋乾燥機)。

3.	風量：
	絕大多數的用戶通常以「定馬力」的方式選用空壓機，事實上「定風量」才是比較正確的方法。用戶應該根據尖離峰的需求風量來選用與配置不同型式與大小的空壓機，設法讓每個用氣時段的耗氣量與空壓機的排氣量相一致。然後根據尖、離峰的負載變化來選擇不同型式的空壓機。「基載」使用離心式或螺旋式「變動負載」使用多台螺旋式搭配變頻式「瞬間負載」使用高壓縮空氣壓機與大型儲氣桶來因應。排氣量的選擇，應該考慮到以下幾點： (A) 目前的需求量 (B) 可能的管路洩漏量 (C) 將來的擴充計畫 (D) 使用的裕度

4.	品質要求：
	如同沖洗水與飲用水需要不同的處理一樣，壓縮空氣也必須根據不同的用氣品質要求，進行不同的處理。通常我們將壓縮空氣分成廠用(PA)、儀用(IA)、呼吸用(BA)及特殊製程用(SPA)等。通常根據ISO 8573-1壓縮空氣品質標準，選用與配置不同型式與等級的乾燥機與精密過濾器，過好的品質浪費能源，不足的品質影響製程，必須慎重考量。空壓機依照其結構的不同，可區分為有油式空壓機及無油式空壓機兩種。有油式：凡必須以潤滑油潤滑機體內部及壓縮部者稱為有油式，其產生的壓力空氣含有微量的油氣，雖含有微量的油份但仍適合一般工業使用。無油式：無油式的零件採用特殊自潤性材質製作，不須藉由潤滑油，即可達到壓縮部的潤滑效果。所以產生的使用空氣中不帶油份，可滿足某些行業需要無油空氣的要求。適用對象：精密工業、醫療、食品、半導體、塗裝等產業。基本上有油式空壓機有廢油的問題，油污的問題，以及洩放水中含有油份這些都必須依照環保法規的要求妥善處理。

5.	控制技術：
	最早期的空壓機使用「機械式壓力開關」、「氣動式控制」進行單機On/Off控制，1980年代隨著PLC可程式控制器的興起，有所謂「多機順序控制」，不過都只停留在對空壓機本身的電器控制上，直到1990年代後期空壓機才進入PC-Based的「多機連鎖控制」，2000年起「變頻控制」技術也風起雲湧。「多機連鎖」、「電子式控制」、「變頻變速」及「遠端監控」等技術，能有效抑制系統調控運轉的損失及備載機組的空車浪費(節約電費25-40%)，使運轉機組均接近全載運轉，穩定供氣壓力(±0.1bar)。可由控制上達到近30％的省能效益。

6.	運轉效率：
	設備運轉在設計接點時，可保有最高的效率，但偏設計點愈遠時，其效率將愈下降，所以規劃時選用了正確的空壓機，日後可節約大量的運轉成本。

7.	安裝通風：
	相較製程與空調設備，空壓機價格相對低廉、耐操、要求不高。因此經常放置於工廠環境最差的角落，漏油、漏氣、漏水、高溫、西曬、潮濕、塵染、通風不良、熱端循環等現象比比皆是。除不利空壓機的運轉外，對於節能也有一定程度的影響。機房空間的大小，通風條件，噪音隔絕，廢熱、廢水回收等都影響能源的使用。此外「集中式」比「分散式」有較低的安裝、保養與監控成本，也可以減少週邊設備投資。

8.	冷卻方式：
	空壓機的冷卻方式基本上分為氣冷和水冷兩種。除非環境特殊，通常在200hp以下建議使用氣冷，200hp以上建議使用水冷。氣冷式不必額外投資冷卻水塔與水泵，但必須有良好的通風；水冷式運轉溫度不受環境的影響，有利空壓機的壽命，唯有結冰爆裂與阻塞的缺點。

9.	電源規格：
	世界各國及各地區有不同的供應電源，不同的電壓，不同的頻率，不同的電氣法規，在選購空壓機時，必須說明使用的電壓，頻率及相數，以便使廠商正確裝配空壓機的電氣控制配備。而電壓需求與電壓降的穩定必須要求空壓機所使用的馬達依照電源的不同，可分為單相或三相：單相：通常的電壓為110V、220V，為方便及安全性而言，1hp以下可使用110V，1hp以上可使用220V，5hp或以上馬力不適用單相電源。三相：通常使用在較大馬力的機種上。低電壓系統(常見的380V~460V)，600hp公上的空壓機建議使用高電壓系統 (3kV~10kV)

10.	維護保養：
	在保養維護上，必須著重耗材使用時數及原廠保固要求，避免使用坊間維修商低價劣品。以節能立場而言首要考量空壓機管理。機房要有適當的保養空間及必要的吊運設施與出入通道。操作人員與保養人員也應該施予不同的節能與維修專業訓練。



While you are planning to own a air compressor system, asides from the purchasing expense, saving electricity cost, increase its life span, provide stable pressure, and decrease its noise and pollution are some questions customers has always been wondering with. Therefore, it is important to evaluate all important factors before purchasing the air compressor system. Here are the ten important factors that customers should evaluate before purchasing:

1.	Main Purpose of compressing air
	Most users seldom think to operate in different usage for different parts of the system. Many users would apply the same input and output for all functions, in results with too much money are being waste.

2.	Pressure
	Every part of air’s maximum and minimum pressure should be well evaluated. Also, the pressure between transferring pipe and cleaning system’s pressure need should be calculated, so then the amount of air being discharged can be fixed. General pipes’ loss is approximate 0.5 kg/cm². During the cleaning process after the air being compressed, it has to go through the dryer or the filter, which usually causes the pressure decreases, approximate at 0.3~0.5 kg/cm² (Filter & Dryer).

3.	Wind Power
	For majority, customers decide the product by its horsepower. The truth is, the wind power is more accurate to choose the model you need. Users should choose the model according to the maximum and minimum wind power requirements, so that each section of the air usage and discharge will be equal. “Base load” uses centrifugal type or screw type “Fluctuating load” uses multi screw type along with variable-frequency type “Momentary load” uses high pressure air compressor and big size air tank There are some factors that users should be aware of about the amount of air discharge: (A) Current requirement (B) Estimation of leakage amount (C) Future expanding plan (D) Tolerance using

4.	Quality Requirements
	Just like water for washing hands and for drinking, the cleaning process is different, air compressor also has different process according to different quality requirements. Usually we categorize compressed air as PA, IA, BA, and SPA. According to ISO 8573-1 compressed air’s quality standard, choosing different models and class of dryer and high precision filter, will results with different quality of air. Therefore, for not letting the good quality resource became wasted and affects the process, it is important to choose the most suitable devices and machines. With the different design of air compressors, it can be separate as with and without oil. With oil: Oil is used to lubricate inner part of air compressor. Although it has a rarely little oil, but it is still perfectly fine for general industry users. Without oil: Parts for without oil models will lubricate itself by its own part design. Therefore, it will be 0% oil contain. It is suitable for: high precision industry, medical industry, food industry, semi-conductor industry, painting and coating industry. Models of air compressor that has oil with it, will contain problems such as slop oil, oil stain, and water with oil leaking. It is important to strictly follow the instructions and policies of environmental protection.

5.	Operating Skill
	In the early days before 1980s, air compressor operated by simply on/off button controls for each device and machine. In the 1990s PLC became popular, operating became easier with multi orders. As year 2000 arrived, variable-frequency operating became the new innovation that contains operating digitally technics that could saved at least 30% of electricity and resources. The technics of variable-frequency operating provided stable pressure at ±0.1bar when it is full load.

6.	Performing Efficiency
	When the performance matches the designing point, the efficiency can be guarantee at its best. However, when its further to the designing point, its efficiency will decrease. It is proved that when choosing the right air compressor, performing cost can be easily saved.

7.	Installation and Ventilation
	Comparing to air-conditioners, air compressor is more inexpensive, durable with lower requirements, so most factories would install it at the corner with bad environment condition such has too humid, too hot, too dusty and other horrible conditions. Installing air compressor in a bad environment condition can negatively affect not only its performance, but also energy saving efficiency. Area size, ventilation environment condition, noise isolation, waste water and heat are some factors that can directly affects to the using of resources. Comparing with distributed systems, centralized system has lower cost in installing, maintain & repair, monitoring, operating, and other accessories.

8.	Cooling Method
	There are two types of cooling method for air compressor: air cooling and water cooling. It is suggested that under 200hp should use air cooling; for the models that are above 200hp should use water cooling. Although air cooling doesn’t have to invest on extra accessories such as water pump or cooling tank, but it is required to have a ventilation environment condition. On the other hand, water cooling type’s performing temperature won’t affected by environment’s temperature, which benefits the life span of air compressor, but icing burst and block up are the main disadvantages.

9.	Electric Power Type
	Different countries have different ways of providing electricity, and also having different voltage, frequency, and restriction on electric using. While users are purchasing the air compressor, it is required to provide the types of voltage, frequency, and the amount of phase power users are using. Voltage need and stability when voltage decrease referring to the motor of air compressor’s electric power using, usually it can be separate in two types: Single Phase: Suitable for 110V, 220V. For safety, below 1hp uses 110V, above 1hp but below 5hp uses 220V. Three Phase: Suitable for large hp machines. Low voltage system for 380V to 460V. Air compressor with 600hp and above is recommend to use high voltage system (3kV to 10kV)


10.	Repair and Maintenance
	It is important that parts and consumable parts should be replaced with original factory’s manufactured, rather the using cheap parts from other unqualified factories. The maintenance principle is based on the SOP management of air compressor. Position of air compressor should have extra space area for maintaining, hanging accessories, and for engineers to easily walk in and out. The person who operates and maintain should take different professional lessons according to their duty.


資料參考：空氣壓縮機系統節能技術手冊，經濟部能源委員會編印。