5 Must-Have Features in a sintered filter cartridge

Let&#;s talk about the sintering process.

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The basic definition of sintering is the process through which the bonding of particles in powder form takes place.

The bonding takes place by diffusion in temperatures that are below the melting point.

In a micron range, a physical limitation does not exist between the metal powder particles as they were initially after the sintering process.

In essence, sintering offers shape- stability to high porosity materials.

It also provides a robust metallic component to the material.

The sintering process mechanically fixes the pores of these materials in regards to the position size.

The sintering metal filter manufacturing process basically involves three main steps.

The first steps include obtaining the powder form of your metal.

You can do this either through grinding, atomization, or chemical decomposition.

At this point, you can either combine this powder with another metal to form an alloy or use it as it is.

The benefit of sintering is that it allows the material to maintain its physical properties.

This process is so simple that there is no such alteration of the element.

Sintered Metal Filters

The second step involves pouring the powder into a die from where you can shape the design of your filter.

Forming the composition of the filter takes place under room temperature and high pressure.

The amount of pressure you can apply depends on the type of metal you are using since different metals have different malleable degrees.

While in the die, compacting of the metal powder takes place to form a solid filter.

Once this happens, you can go ahead and remove the screen, which is in a solid state, and subject it to a furnace under high heat.

Now, this is what we refer to as sintering.

During the sintering process, the metal particles fuse without having to melt.

This forms a high-strength, rigid and porous filter.

You can alter the porosity of the filter depending on the level of flow of either air or liquid that your screen will be filtering.

To be honest, only the best quality sintered metal filter can work for your application and achieve the results that you want.

However, to be able to pick the best quality sintered metal filter for your application, you need to be vast with their features.

Sintered Metal Filters

Here is an in-depth look at these features.

Physical durability

Physical durability is one of the features of the sintered filter element that you can take advantage of.

The physical strength comes about as a result of the bonding of different metals during the manufacturing process.

Since there is no melting of these metals, they can maintain their physical properties.

It is these physical properties that can offer durability to your sintered filter.

The advantage of this is that your filter can offer quality service for a longer duration without the necessity of replacement.

Durability also implies that you can gain value for your sintered filter on your application.

Temperature resistance

To achieve the best of your filtration, you need a filter that can withstand the temperature of your application.

That is what a sintered metal filter offers for your use.

By choosing a metal that has a high-temperature resistance capability, you can have a sintered filter that fits your application.

The critical thing to note is that sintered metal filters are a product of different metals.

As such, when selecting a sintered metal filter, you need to ensure that the metal has the temperature resistance as your application.

Choosing any sintered metal filter may cause your filter to fail especially if the temperature range is lower than your application.

Corrosion resistance

Many filters fail to achieve the desired level of filtration with time due to corrosion of the screen.

The filter element corrosion occurs when there is a reaction between your filter and either the environment or the fluid that passes through.

Corrosion may be a result of either chemical or physical reaction between your filter and the external factor.

As a result, there is your filter gets &#;eaten away&#; which in turn reduces its efficiency.

However, that is not the case with a sintered metal filter.

No reaction takes place between your filter and the external factor which in turn makes it hard for the filter to be &#;eaten away.&#;

This ensures that your filtration is as effective and as efficient as possible.

Precise filtration

You can obtain the filtration that you desire with a sintered filter.

This is due to the availability of the pores in the element.

The ability to adjust the porous material during filtration makes it quite easy to achieve the level of filtration that you want.

That means that if you want finer filtration, you can easily select a sintered metal filter with tiny pores.

Likewise, if you want average filtration, you can select a sintered metal filter with average pores.

High-quality material

One of the features that you look for when selecting a filter is quality.

Getting a filter that will offer you the best service for a long duration is very vital to your filtration.

The advantage of a sintered metal filter is that you have the highest quality material to select from when purchasing a filter.

The reason for this is that the bonding of different metals ensures that you obtain high-quality metal for your sintered metal filter.

You can have different sintered metal elements which are a result of different bonding metals.

The result is of a higher quality as a result of maintaining the individual properties of the metals.

Varying filtration grade from 0.1 microns to 100 microns

The fact that you can customize your sintered metal filter gives you the advantage of achieving the result that you want.

For instance, you have a wide range of filtration range to select when you are designing your filter.

Filter Beta Ratios &#; Photo Courtesy: Advanced Fluid Systems

You can select from as low as 0.1 microns to as high as 100 microns of the filtration grade that you want your filter to be.

This, of course, depends on the level of filtration that you want to achieve.

If you want to achieve finer filtration, you will select a smaller filtration grade for your application.

Custom pore sizes and flow characteristics

With a sintered metal filter, you are at liberty to customize the pore sizes and the flow characteristics to suit your application.

That is to say; if you want a tiny or large pore size for your filter, you can quickly achieve it using a sintered metal filter.

This is thanks to the ability to control the porosity of the sintered metal filter during the manufacturing process.

Also, you can easily customize the flow of the fluid on your screen to match that of your application.

If the flow of your application is from the bottom to the top or from right to left, you can quickly change your sintered metal filter to correspond with it.

Fully welded sintered metal filter element

During the manufacturing process, you can weld most parts of the sintered metal filter together.

This gives a much more stable filter than screwing the components together.

Screwing can make these components fall apart in an application that has high vibrations.

The disadvantage of this is that you will continuously be maintaining your filter.

This may result in a loss of productivity of your application.

However, you can minimize all these by using a sintered metal filter.

The welding of these filters allows for little movements of the components thereby ensuring maximum productivity of your application.

Dirt holding capacity

One of the main features of a sintered metal filter that you will find crucial is the ability to hold the contaminants.

Contaminants holding capacity is essential since it will determine how long you can continue operating without stopping.

You can have different sintered metal filters that have different dirt holding capacities.

The choice of which sintered metal filter to pick depends on the application that you are using.

Large applications need a high dirt holding capacity filter whereas if you have a small application, a smaller capacity filter will do.

Type of sintered metal filter material

Another feature that is very common with sintered metal filters is that you can select the metal you want.

We have seen the sintering process is all about the bonding of different metals either individually or as alloys.

The resulting product is a durable and efficient filter that you can use.

This, therefore, means that you are at liberty to select the right metal that you can use for sintering your filter.

Among the considerations to make when selecting a metal for your sintered metal filter is the application that you are going to use.

The metal needs to withstand the conditions of the application for it to be effective.

High permeability

Permeability refers to the pressure drop measurement of a given fluid at a given flow in a filtration unit area.

High permeability is one of the characteristics of a sintered metal filter that makes it adaptable to its function.

For efficient filtration to occur, there is a need for a high-pressure drop which this feature makes it possible for the sintered filter to have.

The pressure drop needs to be in line with the maximum temperature of your fluid for efficient filtration to take place.

Different sintered metal filters have different permeability levels that you can select depending on the fluid that you are filtering.

Sintered Metal Filter Pressure Drop

An attractive feature of a sintered filter metal is its ability to maintain the pressure of the fluid of your application.

The advantage of this is that you can completely filter your fluid.

What happens when the pressure drops are that there is a lack of enough force to allow for the fluid to pass through the filter.

As a result, you will find the filtration of your fluid not complete since there will still be the presence of contaminants.

Also, you will find that your application may not be able to achieve the fluid requirement that it needs.

However, the use of a sintered metal filter helps to prevent all this from occurring.

Quality of sintered metal filter disc

There is no doubt on the quality of a sintered metal filter more so the filter disc.

The manufacturing process ensures that you only obtain the best of your sintered metal filter.

The filter disc, in particular, is an important component of your filter.

It is here that the pressure builds up as filtration takes place.

You, therefore, need to ensure that this disc is strong enough to withstand this pressure.

Different filter disc always breaks after some use due to this pressure.

However, the sintered metal filter disc is strong enough to withstand the pressure of fluid for a long duration.

This ensures efficiency during the filtration process.

Sintered Metal Filter Cartridge

The sintered metal filter cartridge is the most important part of your filter.

It is here where the actual filtration takes place.

For more sintered filter cartridgeinformation, please contact us. We will provide professional answers.

As such, sintered metal filter cartridge ensures that you have the best filtration of your fluid.

The durability of this cartridge ensures that you get value for money when you are using them.

Filtration Modes

Outside-in Filtration

Outside-in Filtration design is where the filtration happens on the outer layer of the closed-end tubular filter element (LSP).

One of the ways of cleaning this kind of design is by using hydro- pulse backwash through the assistance of gas.

Outside- infiltration is useful in applications that offer a continuous flow of the fluid.

Since the cleaning is a thorough backwash, you can continue operating your application without having concerns about the contaminants.

Inside-out Filtration

In this design, the filtration of the fluid takes place on the inside of the closed-end tubular filter element (LSI).

Under this design, you can clean your filter using a variety of backwash modes.

These modes include empty shell slurry, full shell slurry, and empty housing wet cake discharging backwash.

You can find this mode ideal if you are using an application that has contaminants with low velocity.

This ensures that all the pollutants flow into the filter element.

There are several characteristics of inside-out filtration.

First, there is less heel, easier removal of contaminants as well as less heel.

As a result, the configuration of this type of filtration is quite easy if you compare it to outside- infiltration.

Secondly, you can select which filter element to use depending on the characteristics of the contaminants.

Attributes include the size and dimensions of the pollutants.

The advantage of this is that it offers you an optimum packing density.

Also, by using the filtrate outlet on the upper side, you are sure of removing all the contaminants along the length of the element.

Lastly, by using the outlet on the lower side, you have an assurance of displacing the filtered fluid from the filter using gas.

By doing this, you increase the filtration capacity of the liquid as well as maximizing on the contaminant removal.

Inside-out Multimode Filtration

Under this design, the filtration of your fluid takes place on the inside of the open-ended tubular filter element (LSX and LSM).

Sealing of the component takes place using two tub sheets meaning your fluid can either flow from the top or bottom of the inlet.

There are two ways that you can operate this design.

That is, as a light contaminant cleaning the filter with fluid filtration being the key.

You can also operate as a high contaminant recovery filter.

The multimodal cross-flow design allows you to operate continuously since there is a side outlet that will enable you to remove the contaminants.

You can also operate this design in batches by terminating the filtration process once it reaches the levels of the contaminants.

Once you are through with the filtration, you can clean the filter using the backwash process.

There are several advantages that you may gain from using this kind of sintered filter design.

First, it is highly preferred when there are highly specific gravity contaminants in the fluid.

The flow design usually is an upward flow mode in such scenarios.

Secondly, this design gives out the highest contaminant removal level and also you can conveniently wash the filter.

You also can operate the system either in crossflow mode or in the barrier.

Another advantage is that where the flow rate allows, you can use single vessel filters.

This will enable you to stop for backwash to occur or for maintenance purposes.

In cases where there is a continuous flow, you can use dual sintered filter systems.

This will allow for short offline periods for maintenance purposes to take place.

Lastly, for continuous operations, you can use the three sintered filter system.

A sintered filter is a type of filter that is made from powder materials, using pressure and heat to make them bond together while keeping a porous structure.

If you want to learn more about sinter filters, this blog has these parts you may like to read:

• Characteristics of Different Sintered Materials
• Main Features of Sintered Filters
• Steps of Producing Sinter Filters
• Advantages of Sintered Materials
• Potential Disadvantages of Sintered Parts
• Sintered Filter Working Principle
• Industry Applications of Sintered Porous Filters
• Maintenance of Sintered Filter Elements
• Frequently Asked Questions

Characteristics of Different Sintered Materials

The sign is used to represent different degrees.

Main Features of Sintered Filters

Filtration Ratings

The filtration rating is also called filtration accuracy, which refers to the ability to remove specific particles from the fluid. It can be measured by the size of particles that the sintered porous filter trapped.

The filtration rating can be expressed in terms of microns (µm), which represents the particle sizes. Typically, the general filtration rating of sintered metal filters ranges from 0.5 to 100 microns (µm).

Among those sintered filters mentioned above, those used in special environments could offer filtration ratings of a higher level. For instance, the filtration rating of sintered plastic filters can reach 0.2 micron when used in pharmaceutical, biotech, or microelectronics.

Working Temperature

Each sintered material has a specific working temperature range.

Some could be hard to stand at high temperatures like sintered plastic filters could work at 150°C approximately at most, or thermal degradation may occur.

Some have better heat resistance as sintered ceramic elements&#; working temperature can be up to °C.

If the operating temperature is too high that filters can&#;t withstand, the pores gap will change, affecting the filtration efficiency. On the contrary, when the operating temperature goes too low, the whole structure may be brittle, and easy to be damaged.

You may want to know the recommended temperatures of each sintered material:

You need to consider the operating temperature range and the specific requirements of your application. Only in this way can you ensure consistent performance.

Steps of Producing Sinter Filters

Then, how to make sintered parts? Just follow these 4 steps.

Mixing and Blending in Powder Metallurgy (PM)

Depending on your application, you can choose common types of powder materials such as metal powders or polymer powders.

In addition, you can also mix the powders to achieve specific properties.

Powder Stamping

With intense pressure, powder materials are compacted in molds that have variable shapes (sintered disc, sintered plate, sintered tube, etc.). However, the whole porous structure remains relatively loose.

Sintering Process in Powder Metallurgy

The key step of manufacturing is the sintering process in powder metallurgy, which determines the properties of sintered parts.

Filter materials will be heated to a temperature lower than its melting point, bonding the powders together, while keeping physical properties.

Secondary Operations in PM

After the filter elements cool down to room temperature, check the quality according to your requirements.

If there are some deviations, then reprocess (cutting, polishing, or machining). Finally, clean the sinter filters to remove contaminants.

Advantages of Sintered Materials

Why choose sinter filters? Here are some advantages that ensure their reliable filtration performance.

• Corrosion Resistance

Most of the sintered metals have a natural resistance to corrosive chemicals so they can still maintain a good state under chemical reactions.

Sintered glass and sintered ceramic also have excellent performance in corrosion environments.

• Enhanced Purification

You can choose sintered filters of specific filtration accuracy to keep the filtration efficiency at a high level.

In HVAC (Heating, Ventilation, and Air Conditioning) systems, sintered metal filters with filtration ratings ranging from 5 to 20 microns are commonly chosen to protect HVAC equipment from contaminants. These filters can effectively capture various particles in the air.

What&#;s more, the material that does not react chemically with the fluid can avoid the entry of new substances. In all, the filtered results will be more accurate.

• Pressure Sustaining

If there are pressure fluctuations during the filtration, the entire system will be affected to some degree.

Due to their mechanical strength, sintered metal filters are good at maintaining fluid pressure to ensure stable system operation.

• Robust Durability

Sintered filters have better durability and longer service life in extreme temperatures. With proper maintenance, these sintered parts can be used for many years, often ranging from 3 to 10 years or even longer in some cases, which can reduce the number of replacements, thereby saving costs.

Potential Disadvantages of Sintered Parts

Though many advantages are provided, they still have some potential drawbacks that you need to notice:

• Cost

The choice of materials mainly determined the cost of sinter filters. High-performance materials can be more expensive.

Also, the complexion of the manufacturing process adds to the cost.

In March , the price of stainless steel mixed powder (SS-303L) with a diameter of 100 microns in China is about $590,000 /ton.

• Clogging:

As time goes by, small pores may become clogged with particles, reducing the filtration efficiency. In other words, they need regular cleaning and maintenance.

Cleaning may require specialized equipment and procedures. Some sintered elements used in chemical environments can be more challenging to clean thoroughly. This means it costs not only money but also extra time.

• Material Limitations

Raw materials for making sintered filter elements are not of a wide range.

What&#;s more, one material cannot be applied to all situations. So for special environments, the choice will always be limited.

• Production Time

Compared to other filters, the manufacturing time of sintered filters is long. For different sintered materials, the production time of some sintered metals may be longer.

For example, if the production time of a batch of sintered bronze filters is 1 day, the same number of sintered stainless steel filters could take a week or more.

So if buyers need a great amount of sintered filters, it&#;s better to place the order in advance.

Sintered Filter Working Principle

For Oil or Water Treatment

Sintered porous filters are widely used in fluid filtration or liquid filtration, allowing fluid (liquid) to pass through the pores.

When flowing through the filter, particles larger than the pore sizes are trapped, thus the fluid is purified.

For Noise Reduction and Soundproofing

When the sound waves go into the filter, they will cause the air in the filter to vibrate. This movement creates friction and resistance, which turns the energy of sound into heat, reducing the amplitude of the sound waves.

Industry Applications of Porous Filters

Due to plenty of distinct advantages, sintered filters have a wide range of applications.

• Food and Beverage Industry

For beverage production, you can use filter layers to filter pulp and suspended solids to ensure the clarity of the liquid.

Meanwhile, purified water for food processing can also be obtained by water treatment.

• Chemical Industry 

In chemical processing industries, these sintered filters can be used in corrosive environments, like sintered glass filters used in laboratories.

Some chemical waste may be harmful to the environment, which requires some filtration of these substances.

• Electric Industry

You can also use sintered filter elements to remove impurities in the operating conditions. It can maintain the normal operation of the machine and extend the service life.

(For instance, sintered bronze filter discs are used in vents of electric motors to prevent the entry of dust, moisture, and other contaminants while allowing air exchange. This helps to maintain the internal environment of the motor.)

• Petroleum Industry

Porous metal filters are used to remove contaminants from fuels and lubricants, ensuring smooth operation and prolonging the life of machinery.

(Sintered stainless steel filter tubes are used to remove contaminants from crude oil during production and transportation processes. These metal filters help to keep product quality, protect equipment, and prevent pipeline fouling.)

Maintenance of Sintered Filter Elements

Regular Inspection

Visual inspection is to check for signs of damage and decide whether it needs replacement.

Then perform a short filtering action, and test the filtered fluid to see whether the filter layer is clogged.

Sintered Parts Cleaning

After a period of use, there may be some residual dirt on the filter layers, which will cause blockage if not cleaned in time.

• A common method is ultrasonic cleaning, which can effectively remove fine particulates and contaminants.
• If an element&#;s surface has some chemicals that are difficult to wash off, using chemical solutions that can dissolve the contaminants is the easiest way to clean up.

FAQ

After a basic introduction, you may still have some of these questions:

What affects the filtration ratings?

The uniform pore size is the key point to the precision, which affects the final filtration efficiency. What&#;s more, the sintered powder sizes could make a difference.

Why Sintering is Important?

As said above, the numbers and sizes of pores distributed on the filters directly determine the filtration efficiency. It is the temperature and time of sintering that control these factors, that&#;s why sintering does matter.

As delineated by Wikipedia, this method is integral to the fabrication processes employed across various substances, including metals, ceramics, plastics, and more.

Can sintered metal filters be used for sterile filtration in pharmaceutical applications?

Yes, of course they can.

Filtration in the pharmaceutical industry usually involves liquid filtration and gas filtration, which stays in line with the scope of the application of sintered metal filters.

(For example, you can use sintered metal filters in the final filtration, removing residual particles or microorganisms before packaging.)

What filtration rating is a paper coffee filter&#;

Generally, paper coffee filters have average pore sizes ranging from 10 to 20 microns, which vary depending on the material type and brand of the coffee filter.

If you are referring to the espresso puck screens, especially those made from sintered stainless steel, the filtration rating is around 150 microns.

Can porous metal filters be customized?

Yes.

According to your application and requirements, you can customize specific characteristics (pore sizes, powder sizes, sintered materials, shapes, and flow rate) of your porous metal filters.

In addition, the operating environment needs to be considered as well.

Contact us to discuss your requirements of fiber bed mist eliminators. Our experienced sales team can help you identify the options that best suit your needs.