Why do you need to drain the diesel screw air compressor every day? — Maintenance details that you cannot ignore

In industrial sites, mining, infrastructure construction and field operations, diesel screw air compressors have excellent independence and adaptability because they do not rely on electricity, making them an ideal compressed air power source. But many users often overlook a key maintenance action-draining.

When customers ask: "My air compressor has not been drained for two months. Will it have an impact?" Our answer is not only "there is an impact", but "a big impact". This article will discuss in depth the principle of water generation, the consequences of untimely drainage, the standardized drainage process, and the important role of drainage in the diesel screw air compressor system to protect the operation and life of your equipment.

Ⅰ. How is water generated in a diesel screw air compressor?

1. The nature of moisture in compressed air

During the air compression process, the air volume is greatly reduced and the temperature rises rapidly. When the high-temperature compressed air enters a relatively low-temperature environment (such as a gas storage tank or post-processing equipment), the water vapor in it begins to condense and turn into liquid water, forming the so-called "condensed water".

When the diesel screw compressor is running, it usually inhales a large amount of external natural air. This air inevitably contains moisture, especially in the following environments, the moisture content is higher:

• Wet season: such as the plum rain season or the rainy season in the south;

• High humidity areas: such as coastal areas or tropical climates;

• Winter: the outside temperature is low, the air flow cools faster, and it is easier to condense water.

2. The "first line of defense" of air storage tanks and condensed water

The air storage tank is not only a component for storing and regulating the pressure of compressed air, but also the first barrier for water precipitation in the air compressor system. When the compressed air passes through the air storage tank, the gas changes speed inside the tank and hits the wall, accompanied by rapid heat release, so that the water vapor quickly liquefies into condensed water and deposits at the bottom.

Ⅱ. Serious consequences of not draining water

1. The impact of moisture on air quality

Once the compressed air contains water, it will lead to:

• Defects in processes such as sandblasting and spraying that require high gas cleanliness;

• Rust and stagnation inside the pneumatic tool, affecting the accuracy;

• Pneumatic control system malfunctions, reducing automation stability.

2. Water damage to the inside of the equipment

• Corrosion of internal parts: such as the oil-gas separator housing, the inner wall of the gas tank, the cooler, etc.;

• Lubricating oil emulsification and deterioration: water entering the lubrication system will emulsify the lubricating oil, reduce the lubrication performance, and cause wear of bearings, rotors and other parts;

• Oil-gas separation efficiency decreases: the pressure difference of the oil-gas separator increases due to increased humidity, resulting in reduced separation efficiency and increased burden on the machine;

• Solenoid valve or pressure sensor malfunction: Although diesel compressors are mainly controlled mechanically, some intelligent control systems still rely on electronic components and are easily ineffective due to water vapor interference.

Ⅲ. Diesel screw air compressor drainage operation suggestions

Daily drainage-a must-do every day

The CFAIR team recommends that drainage operations must be performed before using the air compressor every day. This action should form a habit and standardize the process:

• Turn off the air compressor before opening the drain valve;

• Slowly open the drain valve at the bottom of the gas tank to drain the water;

• The color and smell of the liquid can be observed. If abnormalities are found (such as blackening or stinking), the lubricating oil status must be checked immediately;

• Close the valve after draining the condensed water to prevent secondary air intake.

Ⅳ. Environmental factors and drainage frequency adjustment

1. High humidity environment

For example, in the rainy season in the south or at the seaside, the moisture content is extremely high and the amount of condensed water is large. The daily drainage frequency should be increased to 2 times, and an additional cold dryer should be used to reduce the gas dew point.

2. Precautions for drainage in winter

• Low temperature will cause condensed water to freeze inside the system or in the drainage pipeline, which may block the drain valve, and even freeze and crack the components in severe cases.

• Drainage must be performed after the machine is used to avoid water freezing (pay attention to safe operation to avoid burns);

• Add heating belt or use antifreeze oil.

Ⅴ. Why diesel air compressors need to pay more attention to drainage?

Compared with electric air compressors, diesel screw air compressors often have more stringent operating environments:

• There are more field operations, and the dust and humidity are more complex;

• The cooling fluctuates frequently and is more prone to condensation;

• There is no external power supply, and some cooling and post-processing rely on mechanical methods, and the precipitation efficiency is relatively limited;

• The life of the lubricating oil depends more on the system sealing and moisture control.

• Therefore, the drainage management of diesel air compressors is the "lifeline" to ensure the reliability and life of the system.

Ⅵ. Maintenance Tips and Practical Cases

1. Practical Case: "Chain Reaction" Caused by Failure to Drain Water

A construction customer reported that the operating efficiency of the diesel air compressor he used dropped significantly. Inspection found that there was serious water accumulation at the bottom of the gas tank, resulting in:

• The pressure difference of the oil-gas separator soared;

• The pneumatic breaker was weak;

• The exhaust contained water and oil, resulting in the failure of the spraying operation;

• The internal cooler of the air compressor was rusted, and the equipment needed to be returned to the factory for repair.

• The fault was attributed only to the failure to drain water for 3 weeks.

  
  

2. Daily Inspection Checklist (printing and posting recommended)

Ⅶ. Summary: A drop of water can also bring down a piece of equipment

The drainage of diesel screw air compressors may seem simple, but the operating mechanism and safety assurance behind it are very complex. Ignoring drainage not only affects air quality, but also directly harms equipment life, work efficiency and customer production plans.

As an air compressor service engineer said: "One minute of drainage a day is better than three hours of maintenance."

CFAIR recommends that you include drainage in the operating procedures and implement them in a standardized manner, so as to truly achieve: "Maintaining equipment is like maintaining a car, and using equipment is like using people" - only by taking good care of it can you achieve stable output.