Air compressor selection and supporting equipment parameters

Air compressor selection and supporting equipment parameters

1. Atmospheric pressure: There is a layer of ambient air called the earth's atmosphere, which is covered by the entire earth due to gravity. The weight of air is applied to the object force, called atmospheric pressure. Air is made up of tiny particles with a certain volume and weight. An atmospheric pressure and temperature of 273K, there are 2.683 × 1019 molecules of air in one cubic centimeter. The reason why we don't feel the atmospheric pressure of the air, there are internal and external bodies, so that the pressure from the internal and external offset, like a file that can be pierced by a finger sticking out of the frame, but remains the same if there are two Fingers, both push and even big power. According to the application of the object pressure is about per square centimeter, which is why we call it 1 kg of atmospheric pressure.

2. Indicating pressure: Air pressure is usually shown on the pressure gauge and usually does not represent the actual pressure of the air. This is at atmospheric pressure, which means that atmospheric pressure does not calculate excessive pressure. Indicative pressure means that the atmospheric pressure is assumed to be zero. It is also called gauge pressure. The gauge pressure = absolute pressure, atmospheric pressure.

3, vacuum degree: When the pressure in the container is lower than the air pressure, the vacuum produced, this is also the negative pressure requirement. With no ring at all (ie 100% vacuum is very difficult to produce).

In general, 760 mm (the mercury column is at 0 degrees) is called a standard measure.

Degree of vacuum: The following atmospheric pressure is read, and the vacuum pressure indicates the pressure difference of the atmospheric pressure container below. The lower the atmospheric pressure of the container, the lower the vacuum, and the vise (not more than 1 atmosphere). If the pressure in the container is the same as the atmospheric pressure, the vacuum is zero, which means there is no vacuum.

4. Absolute pressure: Means of indicating pressure plus atmospheric pressure Absolute pressure is calculated based on the vacuum null hypothesis.

Absolute pressure = indicated pressure + atmospheric pressure

Absolute pressure = atmospheric pressure - vacuum pressure

5, dew point and relative humidity

Like dew at night when the temperature drops, the temperature at which the air compression system also produces steam drops. Because the point is that the temperature of humid air cooling to saturation pressure is the same.

Why? Air and water contain only a certain amount of water. If the pressure or cooling down the volume, there will not be enough air to contain all the water, so the excess water will extract the condensate.

After coming from the air cooler, it is usually completely saturated. The condensate in the separator is supersaturated with air. Therefore, any saturated air (at the dew point) where the temperature drops will produce condensate. The temperature setting can be considered to be in the humid air, which is: the weight of the steam steam is the weight of dry steam.

Therefore, relative humidity

When private secretary = 0, ψ = 0, it is called dry air, and when private secretary = lead, ψ = 1, it is called saturated air.

6, air tank

For air box indications, for example: C - 0.3 / 8 "C" refers to the oxygen cylinder, "0.3" refers to 0.3 cubic meters, and "8" refers to the maximum operating pressure of 8. Air tank function: storage of compressed air; buffer pressure, due to the air pressure from the air tank when the air compressor is charged, the pressure of the discharged air changes, and the air can be used more stably in the air where the terminal pressure is compressed. Eliminating Water Before: Part of the water vapor formed in the air passes through the compressor through liquid droplets, and most of these droplets will be at the bottom of the tank. There is a tank in the air that can manually or automatically drain the dirt bottom drain valve. Select air tank: The pressure in the tank should be equal to the air pressure and the volume should be 1/2 - 1 function the same pressure / 10 on the compressor flow; if the environment allows for larger air tanks can be selected, which are more compressed air and previously eliminated Water is better.

7, dryer

Refrigerated dryers are compressed air compressors that are compressed through a cooler and separated by air and water separators. Stable buffer tanks are usually in a saturated position with 100% relative humidity, and also contain impurities and cooling, such as Petroleum and solid particles cannot be used directly and need to be cleaned and dried.

There are usually three ways to dry the compressed air in the industry

Agents in the elimination of water vapour compression absorption; by selective absorption characteristics, such as absorption compressors.

Dry with some chemical deliquescence function to compress air; such as deliquescence compressor.

The use of compressed air in the received compressed air temperature depends on the steam pressure and reduces the temperature while drying; such as a refrigerated compressed air dryer.

In the above-mentioned air drying of the compression apparatus, the decondensed compressed air dryer is basically not obsolete, while the refrigerating compressor and the absorption compressor are now widely used.

At present, the following features are compared with the absorption compressor refrigeration compressor:

Without compressed air consumption, most users do not have very high requirements for post-compression air dewpoint, use freeze-drying to preserve energy than adsorption dryers.

No valve friction machine has the problem of switching valves, even though there are currently no friction in the freeze dryer valves.

No regular refreshments and absorption agents need to be replaced;

Low-noise operation; dry absorption towers with pressure-emission noise, almost no noise, sound in empty rooms.

Simple daily maintenance, only regular automatic cleaning of water discharge is necessary;

Not very stringent after the previous gas source was required for treatment, it had enough of a freeze dryer quality standard for a regular oil and water separator; compared with an absorbent dryer, the treatment of the compressed air freeze dryer had "pressure dew point 0°C. The above "only, so the air is dry, is away from the absorption dryer. In some areas of application, freeze dryers are far from meeting the requirements of post-source gas and dry electronics, such as the requirements of pneumatic instruments.

8, freeze dryer parameters

The main technical parameters of the freeze-dryer: processing capacity (0.5-100Nm3/min); - inlet air temperature (65 °C); - function pressure (pressure 10MPa); - compressor or machine power supply (different amplitude), frozen Machine cooling It includes condenser motor power air-cooling water consumption (t/h) or air volume m3/h; pressure dew point (10°C). The pressure dew point influences the position of the inlet after the compressed air, so we cannot simply guarantee the freeze-drying dew point temperature. Instead, we specify the nominal dew point value of the function.

9, choose the principle of dryer

In the method of cooling, there are air cooling and water cooling types; in the intake air temperature conditions have inlet heat (less than 80 °C) and normal (45 °C or less) type; temperature inlet operating pressure is low pressure type (0.3 To 0.6 megapascal), normal type (0.6 0.9 0.95 MPa) and medium, high pressure type (≥ pressure 1.0 MPa).

The dryer can be selected according to the air quality requirements and dew point from the air compressor related system pressure. Associated filters refer to the digital samples of the relevant equipment air compressor and the needs of the user.

1, air conditioning (refrigeration equipment): This is an air conditioning equipment, follow the principle of ordinary air conditioning cooling, broadcast according to the flow of coal mines. It consists of refrigerators, air coolers, section ventilation, air ducts, cooling water piping systems. Around the business area, the heat is spread through the refrigerator water. With segmented ventilation, the air passes through the air cooler and then sends the air tube's business area to maintain the temperature business area below 26°C.