Pm filter

Types of PM filters

PM filters for diesel engines are made in different types that focus on different removal methods. According to the working principle, they can be categorized into three key types: mechanical, thermal, and electrical PM filters.

• Mechanical PM filters

  Mechanical PM filters use the mechanical removal method to trap and collect particulate matter. The most common type is the diesel particulate filter (DPF), which acts as a mesh that captures soot and ash from the exhaust gas. Filters need regular maintenance and cleaning, as they can become clogged and affect the performance of the diesel engine.

• Thermal PM filters

  Thermal PM filters utilize the thermal removal method to remove particulate matter by oxidizing it at high temperatures. Ashless PM filters play the role here. They have a porous structure that captures particulate matter, which is then oxidized during combustion. Thermal PM filters also include candle filters. Candle filters consist of numerous filter elements resembling candles that capture soot inside their porous walls. The accumulated soot is then burned off during regeneration, a process that requires elevated temperatures.

• Electrical PM filters

  Electrical PM filters work by applying the electrical removal method. That means they trap particulate matter using electrostatic forces. The filters are usually compact devices that consist of two electrodes between which high-voltage direct current flows. When the exhaust gas containing particulate matter passes through the filter, the electrostatic charges act on the particles, pulling them to the oppositely charged electrodes, thus separating them from the exhaust gas. Electrical PM filters are self-cleaning devices. They can clean themselves during operation by using different operating modes, which makes them maintenance-free in the purest sense.

Specification and maintenance of PM filters

Specification

• Dimensions:

  The dimensions of a PM filter will vary depending on the vehicle it is manufactured for. A universal DPF usually has the DimesionSRR in the table below.

  Dimesion	Dimension
  Length	400-600mm
  Diameter	150-200mm
  Channel/Cell Count	30000-60000
  Wall thickness	1-3mm
  Substrate Material	Cordierite or Silicon Carbide

• Filtering Efficiency:

  PM filters are usually graded in terms of their filtering efficiency. They can have up to 99% efficiency in capturing particulate matter. This grading will usually be seen on the supplier catalog of PM filters.

• End Connections:

  Depending on the specification and requirement of the car manufacturer or application, the end connections of a PM filter may have flanges or slip connections. The connection may also be integrated with gaskets and clamps for a secure and airtight fit.

Maintenance

Generally, PM filters are designed for the car exhaust system to have a life span of over 100,000 km. They will require occasional maintenance and care to achieve this and spare costly replacement costs.

Wash the filter carefully and remove any elec. connectors using the manufacturer’s instructions. This includes using a high-speed jet of water and soap from both ends. Before putting the filter back into the system, make sure it is completely dry. Use a blow dryer if the filter is still damp. If it is not completely dry, it can catch fire the first time in use.

Around 95% of PM filters are cleanable. They can be restored to their original state by performing a process known as "burn-off." The burn-off procedure entails subjecting the filter to extremely high temperatures, which will incinerate the deposited soot and carbon ash. Thee filters will have an identifying mark or stamp, a burn-off label, or a manufacturer's service manual indication.

Even though PM filters are essential components of a vehicle's exhaust system, some people will consider removing them to enhance engine performance. The action is unlawful because the filter's primary role is to keep the air clean. Furthermore, removing the PM filter may have a detrimental impact on the vehicle's performance. It could trigger the check engine light, negatively affecting the vehicle's resale value.

Uses of PM filters

• Machinery Industry:

  PM filters are used in heavy machinery like excavators, bulldozers, and loaders. These filters are used to clean the air before reaching the engine. So, it works efficiently and reduces the need for maintenance.

• The packaging industry:

  Packaging machines are designed to work with filtered air to prevent any contamination of products. PM filters help maintain a clean environment within the machines. As a result, there is a low risk of product defects and improved packaging integrity.

• Food processing industry:

  Food-processing factories use PM filters to prevent particulate matter from entering the sensitive machinery at food-processing facilities. Keeping harmful particles out prolongs the lifespan of equipment like conveyors, mixers, and crushers.

• Farming industry:

  In the farming industry, tractors, harvesters, and other farming equipment use PM filters. The PM filters help to protect the engine from farm dust, pollen, and other fine particles. It ensures reliable performance and reduces maintenance on the equipment.

• Electricity generation industry:

  In power plants, PM filters are used in gas turbines, steam turbines, and internal combustion engines. The PM filters reduce wear and tear on generators, fans, and blowers. Hence, they help keep equipment operating reliably over longer periods.

• Mining industry:

  In mines, PM filters play a crucial role in protecting engine components from abrasive particles like coal dust, silica, and rock fines. Respiratory health hazards of mine workers are reduced by protecting the vehicles and equipment from these fine particles.

How to choose PM filters

Before buying a PM filter, the following factors need to be considered:

• Application Environment:

  The working environment of the filter will use needs to be considered. The type of particulate matter, its concentration, the humidity of the air, temperature, and presence of chemically aggressive substances will all impact the choice of the PM filter.

• Filter Effectiveness:

  Choose a PM filter that has been validated by internationally recognized testing standards. Ensure the selected filter has the capacity to capture the specific size of particulate matter that poses the greatest risk to the health of the end user.

• System Compatibility:

  Determine whether the chosen filter can be easily integrated into the existing system. If a proprietary basket or housing is needed to hold the filter, that will also need to be ordered along with the filter.

• Cost:

  While the initial cost of the filter is a consideration, the buyer also needs to look at the factors affecting the total cost over the lifetime of the filter. The factors include, but are not limited to, the replacement frequency and the energy costs associated with the pressure drop across the filter.

• Regulatory Compliance:

  The filter selected needs to comply with local regulations. It should also meet the procurement standards set by the buyer's organization if it is being bought for use in a commercial application.

• Manufacturer Reputation:

  Choose a manufacturer that has established a strong reputation because they have robust quality management systems. These systems ensure consistent quality and reliable performance from their filters.

PM filter FAQ

Q1: What does the PM in pm filters mean?

A1: In the context of the PM filter, the abbreviation “PM” stands for particulate matter. As such, it refers tiny solid or liquid particles floating in the air.

Q2: How do PM filters work?

A2: The PM filters use a labyrinth structure to trap particles. When air passes through the labyrinth, large particles collide with the walls and get trapped. Other smaller particles undergo multiple changes of directions and eventually get caught in the filter. Once the filter has trapped enough particles, it needs to get cleaned or replaced.

Q3: Why do people need PM filters in their cars?

A3: Car PM filters are essential for reducing the amount of particulate matter emitted into the air. By trapping these particles, PM filters improve air quality and protect human health. In cities with high levels of pollution, PM filters in cars are crucial.

Q4: Can PM filters be recycled?

A4: Some manufacturers have systems in place to recycle PM filters. In this case, the filters would be cleaned, and the materials used to make them would be retrieved and reused. However, recycling PM filters isn’t common.

Q5: How much does a PM filter cost?

A5: The cost of PM filters depends on the model and brand. Typical prices range anywhere between a budget car's simple $22 to $580 luxury vehicles' advanced filters.