What Is an Exhaust Cleaner?
Exhaust cleaners are air cleaning devices used at the exhaust ports of solenoid valves and cylinders in pneumatic systems.
Exhaust cleaners serve two purposes: first, they reduce the noise generated by the exhaust. The sound deadening performance is higher than that of a silencer, with an effect of 35 dB or more.
The second is to remove oil and dust from the compressed air exhausted from the pneumatic system. Installing an exhaust cleaner will help to collect these and properly discharge them. Installing an exhaust cleaner will provide a quiet and clean working environment.
Uses of Exhaust Cleaners
Exhaust cleaners are used to remove noise from the exhaust of a pneumatic system and mist oil and other particles in the exhaust. The pneumatic system contains three units: an “air filter,” a “regulator,” and a “lubricator,” which perform the following functions:
- Removes impurities generated and mixed in pneumatic lines
- Pressurization and pressure maintenance
- Lubricant supply
These features ensure stable operation of the pneumatic system and prevent deterioration and breakdowns. Compressed air passing through the unit has the problem of generating “noise” and “contamination” during exhaust. Noise can be reduced by using silencers, but compressed air contaminated with dust and oil mist requires countermeasures.
If left unchecked, the problem can cause contamination and clogging of the discharge port, eventually leading to equipment failure. Furthermore, there is a risk of adverse effects on the human body, causing respiratory and internal diseases. Exhaust cleaners are installed as a countermeasure.
Exhaust cleaners can be installed to remove dust and mist oil from the exhaust in addition to exhaust noise.
Principle of Exhaust Cleaners
Exhaust cleaners purify exhaust and collect oil with a filtering material called an “element. This “element” also has a muffling effect.
1. How Oil Mist Is Generated
Actuators such as air cylinders are widely used in lubrication-free devices that can be used without lubrication by adhering the required amount of grease during assembly.
On the other hand, lubrication of cylinders may be done by mixing oil into compressed air using a lubricator. Then, oil is also mixed in the exhaust air, and oil mist is generated.
2. Purify the Discharged Compressed Air
This compressed air, which contains oil mist and dust, is purified by passing it through an exhaust cleaner. This is where the filtering material inside the exhaust cleaner, called the “element,” comes in.
The oil in the exhaust is filtered on the surface and inside the element, and further condensed and collected by falling down inside and on the surface of the element and accumulating in the oil case section.
3. Drain the Collected Oil
Collected oil is discharged from the drain port using a “drain cock” or “drain pipe” system. In a drain cock, oil is drained by opening the cock. Drain piping is a method for constantly draining oil by connecting oil reservoirs with piping. The oil is also passed through an element to muffle the sound.
How to Choose an Exhaust Cleaner
The size varies depending on the effective cross-sectional area and the maximum treatment flow rate, so selection is based on the nature of the use. The basic rule of thumb is to select an exhaust cleaner with a treatment capacity greater than the maximum required volume of compressed air exhausted from the solenoid valve.
When multiple solenoid valves are used in a centralized piping system, calculate the maximum required peak air volume, including the volume of the piping connected to the actuators and other equipment operating simultaneously. The equipment is then selected so that the value is less than or equal to the maximum process flow rate of the exhaust cleaner.
Note that using more than the maximum throughput of the exhaust cleaner may cause oil to be splashed around or damage the element.
Other Information on Exhaust Cleaners
Element Clogging
Exhaust cleaners have a smaller effective cross-sectional area and clog the element more quickly than regular silencers. As a guideline for detecting element clogging, measure the internal pressure during exhaust.
If the internal pressure rises above a certain level, it is a sign that the element is not venting well and is considered to be clogged. Normally, replace the element before it reaches 0.1 Mpa.