ISO Standard for Compressed Air Dryer

INTERNATIONAL STANDARD ISO 8573-1 

Compressed Air Dryer Contaminants and Purity Classes

1. Scope
This part of ISO 8573 specifies purity classes of compressed air with respect to particles, water and oil, independent of the location in the compressed air system at which the air is specified or measured.
This part of ISO 8573 provides general information about contaminants in compressed air systems as well as links to the other parts of ISO 8573, either for the measurement of compressed air purity or the specification of
compressed air purity requirements.
In addition to the above-mentioned contaminants of particles, water and oil, this part of ISO 8573 also identifies gaseous and microbiological contaminants. Guidance is given in Annex A as to the application of this part of ISO 8573.

2. Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 7183, Compressed-air dryers — Specification and testing
ISO 8573-2, Compressed air — Part 2: Test methods for oil aerosol content
ISO 8573-3, Compressed air — Part 3: Test methods for measurement of humidity
ISO 8573-4, Compressed air — Part 4: Test methods for solid particle content
ISO 8573-5, Compressed air — Part 5: Test methods for oil vapour and organic solvent content
ISO 8573-6, Compressed air — Part 6: Test methods for gaseous contaminant content
ISO 8573-7, Compressed air — Part 7: Test method for viable microbiological contaminant content
ISO 8573-8, Compressed air — Part 8: Test methods for solid particle content by mass concentration
ISO 8573-9, Compressed air — Part 9: Test methods for liquid water content

3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7183, ISO 8573-7 and the following apply.
3.1
aerosol
suspension in a gaseous medium of solid particles, liquid particles or solid and liquid particles having
negligible fall-velocity/settling-velocity
3.2
agglomerate
group of two or more particles combined, joined or formed into a cluster by any means
3.3
lubricant/coolant
fluid used to remove heat and reduce friction in a compressor
3.4
dewpoint
temperature at which water vapour begins to condense
3.5
hydrocarbon
organic compound consisting mainly of hydrogen and carbon
3.6
microbiological contaminants
viable colony-forming units, which can be of bacteria, fungi or yeasts
3.7
oil
mixture of hydrocarbons composed of six or more carbon atoms (C6+)
3.8
particle
small discrete mass of solid or liquid matter
3.9
particle size
d
length of the greatest distance between two external boundaries
3.10
pressure dewpoint
dewpoint of the air at the specified pressure
3.11
relative water vapour pressure
relative humidity
ratio of the partial pressure of water vapour to its saturation pressure at the same temperature
3.12
vapour
gas that is at a temperature below its critical temperature and that, therefore, can be liquefied by isothermal
compression

4 Reference conditions
The reference conditions for gas volumes shall be as follows:
? air temperature 20 °C
? absolute air pressure 100 kPa = [1 bar ](a)
? relative water vapour pressure 0

5 Compressed air purity classes


5.1 General
The three major contaminants in compressed air are solid particles, water and oil; these are categorized by compressed air purity classes.
These compressed air purity classes group the concentrations of each of the above contaminants into ranges, each range being given its own purity class index. The range limits are aligned to those figures found in practice.
When required, all other contaminants should be stated directly by the specific concentrations allowed, or determined within the compressed air supply; see 6.4.


5.2 Particle classes
The particle purity classes are identified and defined in Table 1. Measurements shall be made in accordance with ISO 8573-4 and, when required, ISO 8573-8.
Where it is determined that there are particles with a size greater than 5 μm, then the classification of 1 to 5 cannot be applied.

5.3 Humidity and liquid water classes
The humidity and liquid water purity classes are identified and defined in Table 2. Measurements shall be made in accordance with ISO 8573-3 and, when required, ISO 8573-9.

5.4 Oil classes
The total oil purity classes are identified and defined in Table 3. Measurements for liquid oil and aerosols of oil shall be made in accordance with ISO 8573-2. It is considered that, for classes 3, 4 and X, the oil vapour
content is not expected to significantly affect the total concentration; therefore, the measurement of vapour is optional. Where it is deemed necessary to measure the oil vapour, then ISO 8573-5 shall be used.

5.5 Gaseous contaminants
No purity classes are identified for gaseous contaminants; the presentation of contaminant levels is given in 6.4. Values for gaseous contaminants shall be measured in accordance with ISO 8573-6.
5.6 Microbiological contaminants No purity classes are identified for microbiological contaminants; the presentation of contaminant levels is given in 6.4. Values for microbiological contaminants shall be measured in accordance with ISO 8573-7.

 

6 Designation


6.1 Designation principle
The designation principle of the purity class of compressed air at the specified measuring point shall include the following information in the order given and separated by a colon: ISO 8573-1:2010 [A:B:C]
where
A is the purity class for particles; see Table 1;
B is the purity class for humidity and liquid water; see Table 2;
C is the purity class for oil; see Table 3.
6.2 Unspecified designation
When a class for any particular contaminant A, B, or C is not specified, the designation shall be replaced by a hyphen. In the example given below, there is no humidity or liquid water classification. ISO 8573-1:2010 [A:–:C]
6.3 Class X designation
When the contamination level falls within class X, then the highest concentration of the contaminant shall be given in round brackets. In the example given below, the concentration of liquid water, Cw, is 15 g/m3.
ISO 8573-1:2010 [A:X(15):C]
6.4 Gaseous or microbiological contaminants designation (optional)
Gaseous and microbiological contaminants shall be identified as an additional item to the designation given in
6.1 as follows:
? ISO 8573-6 [contaminant & value & unit of measure];
? ISO 8573-6 [possible further contaminant & value & unit of measure];
? ISO 8573-7 [value cfu/m3].

 

EXAMPLE ISO 8573-1:2010 [A:B:C]
? [SO2 u 0,01 mg/kg];
? [CO2 u 1 mg/kg];
? [CO u 0,1 mg/kg];
? [5 (cfu)/m3] (where cfu designates colony-forming units).





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Gem Equipments entered the engineering and fabrication industry in 1984. We specialise in design, engineering and fabrication of Cooling Towers, Compressed Air Dryers, Wall Mounting Compressed air dryers, High Pressure Compressed air dryers, All Aluminium Compressed air dryers, Copper Coil Compressed air dryers, Dual Frequency Compressed air dryers, General Purpose Compressed air dryers, Logic Controller Compressed air dryers, Energy Saving Digital Compressed air dryers, Series Heatless Compressed air dryers, Desiccant Compressed air dryers, Bottle Type Cooling Tower, Adiabatic Cooling Towers, Cross Flow Cooling Tower, Compressed Air Receiver, Compressed Air Filters, Industrial Chillers and Compressed Air Treatment Accessories. A compressed air dryers is a device designed to remove moisture from compressed air. This compressed air dryers is essential in various industrial applications to ensure the efficiency and longevity of equipment.The compressed air dryers works by reducing the dew point of the air, preventing condensation and corrosion in the system. The design of a compressed air dryers varies depending on the type of compressed air dryers. Common types include refrigerated compressed air dryers, desiccant compressed air dryers, and membrane compressed air dryers. Each compressed air dryers type has its unique structure and method for removing moisture from the air. For instance, a refrigerated dryers cools the air to condense water vapor, while a desiccant compressed air dryers uses absorbent materials to remove moisture. The working principle of a compressed air dryers involves several stages to ensure efficient moisture removal. Initially, the air enters the the compressed air dryers and passes through a pre-filter to remove large particles. This pre-filter stage is crucial for protecting the compressed air dryers from potential damage caused by contaminants. The air then moves into the main drying chamber, where the compressed air dryers removes moisture through different mechanisms depending on the type of compressed air dryers. In a refrigerated compressed air dryers, the air is cooled to condense water vapor. The cooling process in the refrigerated compressed air dryers lowers the air temperature, causing the moisture to condense into liquid form. This condensed water is then drained out of the compressed air dryers, leaving the air dry. The dried air is then reheated to prevent condensation in the downstream piping. In a desiccant compressed air dryers, the air passes through desiccant material that absorbs moisture. The desiccant dryers uses materials such as silica gel or activated alumina to attract and hold water molecules. As the air flows through the desiccant compressed air dryers, the moisture is absorbed by the desiccant material, resulting in dry air. The desiccant compressed air dryers typically has a regeneration cycle to remove the absorbed moisture from the desiccant, ensuring continuous operation.In a membrane compressed air dryers, the air passes through a semi-permeable membrane that allows water vapor to pass through while retaining the dry air. The membrane dryers separates moisture from the air based on the difference in partial pressure across the membrane. This process in the membrane compressed air dryers ensures that only dry air reaches the end-use application. Applications: Compressed air dryers are used in various industries, including manufacturing, food processing, and pharmaceuticals. These dryers are crucial in applications where moisture-free air is essential for product quality and process efficiency. For example, in the food industry, a dryers ensures that air used in packaging is dry, preventing contamination. In the pharmaceutical industry, a dryers is used to maintain the integrity of sensitive products. Types of Compressed Air Dryers:Refrigerated compressed air Dryers: This compressed air dryers cools the air to condense and remove moisture.1. Desiccant compressed air Dryers: This compressed air dryers uses desiccant materials to absorb moisture from the air. 2. Membrane compressed air Dryers: This compressed air dryers uses a semi-permeable membrane to separate moisture from the air.3. Deliquescent compressed air Dryers: This compressed air dryers uses a hygroscopic substance to absorb moisture. 4. Heatless compressed air Dryers: This compressed air dryers uses a desiccant material that is regenerated without heat.5. Heated compressed air Dryers: This compressed air dryers uses heat to regenerate the desiccant material. A cooling tower is a crucial component in industrial production, designed to reduce heat from the plant and enhance production efficiency. Cooling towers vary in size, from small units to extremely large structures, and are used to cool industrial hot water. A cooling tower extracts heat from a building and releases it into the atmosphere, returning cooler water to the system. Industrial pipes transport the heated water to the cooling tower, where it is cooled and referred to as condenser water due to its role in absorbing heat from the chiller’s cooling coil. India’s rapid industrialization and production growth necessitate the construction of more factories, each requiring efficient cooling towers. Towertech stands out as a leading provider of cooling towers, known for their high-quality and reliable products. The interior features of cooling towers differ based on the cooling demands of a structure, with the size of the structure determining the cooling capacity required. 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Here are some common types: o Cross flow Cooling tower o Modular cooling tower o Round shape cooling tower or Bottle Type Cooling Tower o Square Type Cooling Tower or Rectangular Type Cooling Tower OPERATIONS OF A COOLING TOWER The operation of a cooling tower involves several key components and processes: 1. Water Circulation: Hot water from the industrial process is pumped to the top of the cooling tower. 2. Water Distribution: The water is distributed evenly over the fill media using spray nozzles or distribution basins. 3. Air Flow: Air is drawn or pushed through the tower by fans (mechanical draft) or by natural convection (natural draft). 4. Heat Exchange: As water flows over the fill media, it comes into contact with the air, and a small portion evaporates, removing heat from the remaining water. 5. Cooling: The cooled water collects in the basin at the bottom of the tower. 6. 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Design and Structure: The square type cooling tower features a rectangular design that facilitates easy installation and maintenance. The cooling tower is equipped with a fan at the top that induces air flow through the tower. Water is distributed evenly over the fill media through spray nozzles, enhancing the cooling efficiency of the cooling tower. Working Principle: The cooling tower operates on the principle of induced draft counter flow. Warm water from the industrial process is pumped to the top of the cooling tower and sprayed over the fill media. As the water flows down, it comes into contact with the air being drawn up by the fan. The air absorbs heat from the water, causing a portion of the water to evaporate. This evaporation removes heat from the remaining water, which is then collected at the bottom of the cooling tower and recirculated back into the industrial process1. Advantages: • Efficient Cooling: The rectangular design allows for uniform air distribution, leading to efficient cooling. • Modular Installation: The square shape makes it easy to install multiple units in parallel for larger cooling capacities. • Low Maintenance: The design of the cooling tower reduces maintenance requirements. Applications: Square type cooling towers are widely used in various industries, including power plants, chemical processing, and HVAC systems, where efficient cooling is essential for process optimization12. Crossflow Cooling Tower Overview: A crossflow cooling tower is a type of cooling tower where the air flows horizontally across the water stream. This cooling tower design allows for efficient heat transfer and is commonly used in various industrial applications. Design and Structure: In a crossflow cooling tower, the hot water from the industrial process is distributed over the fill media from the top. The air enters the cooling tower from the sides and moves horizontally across the falling water. This perpendicular interaction between air and water enhances the cooling efficiency of the cooling tower. Working Principle: The crossflow cooling tower operates on the principle of evaporative cooling. Warm water is pumped to the top of the cooling tower and distributed over the fill media. As the water flows down, it comes into contact with the air moving horizontally. The air absorbs heat from the water, causing a portion of the water to evaporate. This evaporation removes heat from the remaining water, which is then collected at the bottom of the cooling tower and recirculated back into the industrial process. Advantages: • Easy Maintenance: The design of the crossflow cooling tower allows for easy access to internal components, making maintenance simpler. • Energy Efficiency: Crossflow cooling towers generally consume less power compared to other types of cooling towers. • Uniform Air Distribution: The horizontal air flow ensures uniform distribution, leading to efficient cooling. Applications: Crossflow cooling towers are widely used in industries such as power generation, chemical processing, and HVAC systems, where efficient cooling is crucial for process optimization. The cooling tower’s design makes it suitable for various cooling tower applications, ensuring efficient cooling tower performance. The cooling tower’s ability to provide uniform air distribution enhances the cooling tower’s efficiency. Additionally, the cooling tower’s easy maintenance feature makes it a preferred choice for many industries. The cooling tower’s energy efficiency also contributes to its popularity. Overall, the crossflow cooling tower is an excellent choice for industries requiring efficient cooling tower solutions. Modular Cooling Tower Overview: A modular cooling tower is a type of cooling tower designed for flexibility and scalability. This cooling tower can be assembled in modules, allowing for easy expansion and maintenance. Modular cooling towers are commonly used in various industrial applications where efficient cooling tower performance is essential. Design and Structure: In a modular cooling tower, each module functions as an independent cooling tower unit. These modules can be connected to form a larger cooling tower system. The modular design allows for easy installation and customization based on the cooling requirements. The cooling tower modules are equipped with fill media, fans, and water distribution systems to ensure efficient cooling tower operation. Working Principle: The modular cooling tower operates on the principle of evaporative cooling. Warm water is pumped to the top of each cooling tower module and distributed over the fill media. As the water flows down, it comes into contact with the air moving through the cooling tower. The air absorbs heat from the water, causing a portion of the water to evaporate. This evaporation removes heat from the remaining water, which is then collected at the bottom of the cooling tower and recirculated back into the industrial process. Advantages: • Scalability: The modular design of the cooling tower allows for easy expansion by adding more modules. • Flexibility: Modular cooling towers can be customized to meet specific cooling requirements. • Easy Maintenance: Each cooling tower module can be serviced independently, reducing downtime. • Energy Efficiency: Modular cooling towers are designed to optimize energy consumption, making them cost-effective. 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Additionally, the dry cooling towers’s ability to operate efficiently in various environmental conditions makes it a versatile solution for industrial cooling needs. Types of Dry Cooling Towers: 1. Natural Draft Dry cooling towers: This dry cooling towers uses natural convection to draw air through the heat exchanger. 2. Mechanical Draft Dry cooling towers: This dry cooling towers uses fans to force air through the heat exchanger, enhancing cooling efficiency. 3. Indirect Dry cooling towers: This dry cooling towers combines a dry cooling towers with a steam condenser for power plant applications. 4. Hybrid Dry cooling towers: This dry cooling towers integrates both dry and wet cooling technologies to optimize performance. Maintenance Tips: • Regularly inspect the dry cooling towers for any signs of wear or damage. • Ensure the fans and heat exchangers in the dry cooling towers are clean and free from obstructions. • Monitor the performance of the dry cooling towers and address any issues promptly. • Schedule routine maintenance to keep the dry cooling towers operating at peak efficiency. A dry cooling towers is an essential component in many industrial processes, offering significant benefits in terms of water conservation and environmental impact. By using air as the cooling medium, the dry cooling towers provides an efficient and sustainable solution for industrial cooling needs. Whether using a natural draft, mechanical draft, or hybrid dry cooling towers, the advantages of a dry cooling towers are clear. Investing in a high-quality dry cooling towers can lead to improved efficiency, reduced maintenance, and long-term cost savings. The dry cooling towers’s design ensures optimal performance and reliability, making it a preferred choice for many industries. Overall, the dry cooling towers is a versatile and effective solution for various cooling requirements.