Filter
Today, according to the need of various industries for compressed air in different applications, providing high quality air or gas within the class ranges specified by downstream equipment is regarded very vital. In order to provide high quality compressed air, each industrial complex should utilize the compressed air packages or industrial gases.
Today, according to the need of various industries for compressed air in different applications, providing high quality air or gas within the class ranges specified by downstream equipment is regarded very vital. In order to provide high quality compressed air, each industrial complex should utilize the compressed air packages or industrial gases.
Today, according to the need of various industries for compressed air in different applications, providing high quality air or gas within the class ranges specified by downstream equipment is regarded very vital. In order to provide high quality compressed air, each industrial complex should utilize the compressed air packages or industrial gases.
Filters are one of the main components of compressed air or industrial gases packages. Filters are designed and manufactured to protect the package sub-equipment against oil, suspended particles, etc. entry. The entry of each of these items into the next equipment will reduce the quality of the output product and reduce the equipment’s life time. This occurrence increases the production and maintenance costs. By using proper filtration before and after the equipment, you can reduce the maintenance cost and handle compressed air packages for a long time without worrying about quality decrement in final product.
Important parameters in filter selection
- operating pressure
- Type of filter element
- Air flow
- Element type
- Air class
Filtration is selected based on the required air class at the system’s end point and the equipment used in the package. Each filter can produce a specific class of air based on its element. In the ISO 8573-1 standard, this classification is determined based on the number of solid particles, oil and dew point as a three-digit number in [A:B:C] format, which is illustrated as follows:
A shows the number of solid particles in the output product,
B depicts the range of dew point (Dew Point)
C represents the amount of oil remaining in the output product.
The range of each of these parameters is determined based on the ISO 8573-1 standard in the following tables.
Particle class
Particle classes with more details are discussed in Table 1 taken from ISO 8573-4 and ISO 8573-8 standards.
1.0μm ≤ 5.0μm | 0.5μm < d ≤ 1.0μm | 0.1μm < d ≤ 0.5μm | Class 3 |
As specified by the equipment user or supplier and more stringent the class 1 | As specified by the equipment user or supplier and more stringent the class 1 | As specified by the equipment user or supplier and more stringent the class 1 | 0 |
10≥ | 400≥ | 20000≥ | 1 |
100≥ | 6000≥ | 400000≥ | 2 |
1000≥ | 90000≥ | Not Specified | 3 |
10000≥ | Not Specified | Not Specified | 4 |
100000≥ | Not Specified | Not Specified | 5 |
Not Specified
Mass concentration
CP
mg/m3
| Not Specified
Mass concentration
CP
mg/m3
| Not Specified
Mass concentration
CP
mg/m3
| Class |
0 < CP ≤ 5 | 0 < CP ≤ 5 | 0 < CP ≤ 5 | 6 |
5< CP ≤ 10 | 5< CP ≤ 10 | 5< CP ≤ 10 | 7 |
CP > 10 | CP > 10 | CP > 10 | x |
1.0μm ≤ 5.0μm | 0.5μm < d ≤ 1.0μm | 0.1μm < d ≤ 0.5μm | Class 3 |
As specified by the equipment user or supplier and more stringent the class 1 | As specified by the equipment user or supplier and more stringent the class 1 | As specified by the equipment user or supplier and more stringent the class 1 | 0 |
10≥ | 400≥ | 20000≥ | 1 |
100≥ | 6000≥ | 400000≥ | 2 |
1000≥ | 90000≥ | Not Specified | 3 |
10000≥ | Not Specified | Not Specified | 4 |
100000≥ | Not Specified | Not Specified | 5 |
Not Specified
Mass concentration
CP
mg/m3
| Not Specified
Mass concentration
CP
mg/m3
| Not Specified
Mass concentration
CP
mg/m3
| Class |
0 < CP ≤ 5 | 0 < CP ≤ 5 | 0 < CP ≤ 5 | 6 |
5< CP ≤ 10 | 5< CP ≤ 10 | 5< CP ≤ 10 | 7 |
CP > 10 | CP > 10 | CP > 10 | x |
Humidity class
The moisture class is specified in Table 2. ISO 8573-3 and ISO 8573-9 standards present criteria for classification of compressed air based on its humidity. Dew Point is regarded as a criteria to show the amount of remaining moisture in compressed air. In the dehydration process in compressed air packages and industrial gases, the dew point of the outgoing air is adjusted by adsorption or refrigeration dryers, and the filters have no effect on the humidity class.
Pressure Dew point
oC
| Class |
As specified by the equipment user or supplier and more stringent than class 1 | 0 |
≤ -70 | 1 |
≤ -40 | 2 |
≤ -20 | 3 |
≤ +3 | 4 |
≤ +7 | 5 |
≤ +10 | 6 |
Mass concentration
Cw
mg/m3 | Class |
Cw ≤ 0.5 | 7 |
0.5 < Cw ≤ 5 | 8 |
5< Cw ≤ 10 | 9 |
Cw > 10 | x |
Pressure Dew point
oC
| Class |
As specified by the equipment user or supplier and more stringent than class 1 | 0 |
≤ -70 | 1 |
≤ -40 | 2 |
≤ -20 | 3 |
≤ +3 | 4 |
≤ +7 | 5 |
≤ +10 | 6 |
Mass concentration
Cw
mg/m3 | Class |
Cw ≤ 0.5 | 7 |
0.5 < Cw ≤ 5 | 8 |
5< Cw ≤ 10 | 9 |
Cw > 10 | x |
Oil class
The oil class is listed in Table 3. ISO 8573-2 standard is indicates the amount of remaining oil in each class.
Concentration of total oil
(Liquid, aerosol and vapour)
Mg/m3 | Class |
As specified by the equipment user or supplier and more stringent than class 1 | 0 |
≤ 0.01 | 1 |
≤ 0.1 | 2 |
≤ 1 | 3 |
≤ 5 | 4 |
> 5 | x |
Concentration of total oil
(Liquid, aerosol and vapour)
Mg/m3 | Class |
As specified by the equipment user or supplier and more stringent than class 1 | 0 |
≤ 0.01 | 1 |
≤ 0.1 | 2 |
≤ 1 | 3 |
≤ 5 | 4 |
> 5 | x |
All types of filter elements
Filters are divided into different categories based on the pore size of the elements. It should be noted that usually the pore size of the elements is in the range between 15 µm and 0.01 µm.
The class of particles and oil based on different elements is specified in the table below.
FILTER ELEMENTS | FILTER ELEMENTS | FILTER ELEMENTS | FILTER ELEMENTS | FILTER ELEMENTS | FILTER ELEMENTS | |
|---|---|---|---|---|---|---|
A
Activated
Carbon
| S
Microliter
0.01 μm | M
Microliter
0. 1 μm | R
Prefilter
1 μm | P
Prefilter
3 μm
| B
Prefilter
15 μm
| |
1 | 1 | 2 | 3 | 6 | 7 | quality class- solids (ISO 8573-1) |
< 0.005 | < 0.01 | <0.1 | – | – | – | Residual oil content (mg/m3) |
1 | 1 | 2 | – | – | – | quality class- oils (ISO 8573-1) |
FILTER ELEMENTS | FILTER ELEMENTS | FILTER ELEMENTS | FILTER ELEMENTS | FILTER ELEMENTS | FILTER ELEMENTS | |
|---|---|---|---|---|---|---|
A
Activated
Carbon
| S
Microliter
0.01 μm | M
Microliter
0. 1 μm | R
Prefilter
1 μm | P
Prefilter
3 μm
| B
Prefilter
15 μm
| |
1 | 1 | 2 | 3 | 6 | 7 | quality class- solids (ISO 8573-1) |
< 0.005 | < 0.01 | <0.1 | – | – | – | Residual oil content (mg/m3) |
1 | 1 | 2 | – | – | – | quality class- oils (ISO 8573-1) |
Elements type
One of the key parameters affecting the air class value of filters is the filter element type. The absorption rate of the elements varies based on the absorption capacity of the constituents of the elements. The conventional filter element types can be mentioned as porous rice, acrylic fiber, borosilicate microfibers, active carbon composition and borosilicate microfibers.
Air flow
Filters must be able to receive the passing flow. If the fine filters are selected, high pressure drop and lack of proper filtration will occur which cause disruption in the proper functioning of the package.
HAVAYAR industrial group has the ability to manufacture filters in different sizes based on DIN, ASME and HAVAYAR standards in different capacities based on customers’ needs.
Repair and maintenance
The time to replace the elements is determined by the amount of pressure drop which is recorded by the pressure difference indicator installed on each filter. This pressure drop is caused by the elements being saturated with oil or suspended solid particles. After the pressure drop reaches the set limit, the filters return to their original operating state by replacing the elements.
Frequently Asked Questions
F Filters are one of the main components of compressed air or industrial gases packages. Filters are designed and manufactured to protect the package sub-equipment against oil, suspended particles, etc. entry. The entry of each of these items into the next equipment will reduce the quality of the output product and reduce the equipment’s life time. This occurrence increases the production and maintenance costs. By using proper filtration before and after the equipment, you can reduce the maintenance cost and handle compressed air packages for a long time without worrying about quality decrement in final product.
- operating pressure
- Type of filter element
- Air flow
- Element type
- Air class
ISO 8573-3 and ISO 8573-9 standards present criteria for classification of compressed air based on its humidity. Dew Point is regarded as a criteria to show the amount of remaining moisture in compressed air. In the dehydration process in compressed air packages and industrial gases, the dew point of the outgoing air is adjusted by adsorption or refrigeration dryers, and the filters have no effect on the humidity class.