ALL YOU NEED TO KNOW ABOUT SINTERED METAL FILTERS
A filter is an everyday item that we utilize in separating impurities from any fluid substance. These impurities or contaminants may be dense objects, dust, dirt, or any unwanted material present in the fluid. The fluid can be either gaseous or liquid.
For today's article, we will be critically analyzing the sintered metal filter. We will be exploring what they are, their advantages when set side by side with varying filter types, how they are made, and where they can be applied.
What Is Sintering About?
In the simple sense, sintering is the process of creating a solid mass of material by applying either heat or pressure to the material without liquefying it.
In metallurgy, the sintering process involves converting metal powders to end-use parts by bonding the metal powders. This process occurs by inducing temperatures below the melting point of the metal powders.
At the end of the sintering process, the physical limit between the metal powders is. This alters the material's pores mechanically, rearranging them according to position size.
The entire process stabilizes the shape of porous materials, also providing a robust metallic component.
What Are Sintered Metals?
A sintered metal is a metallic component produced by bonding various metal powders together through the application of heat below their melting point.
One can obtain these metal powders by atomizing or grinding the metal. You can even chemically decompose the metals to obtain their powders.
The sintering procedure is metallurgical, and it is possible to utilize various metal alloys such as titanium, bronze, copper, nickel, aluminum, and stainless steel for the procedure. It all depends on the property you want to acquire.
Sintered Metal Filter
A sintered metal filter is a filter produced via the sintering process. As earlier mentioned, you need to apply heat to the metal powder to bond them together, but the temperature must be below the metals' melting point so that they retain their properties.
If you melt the metal powders, they lose their unique individual physical attributes. But the qualities they possess are what makes the sintered metal filter highly sought after.
What Are the Advantages of Sintered Metal Filters?
Sintered metal filters have some advantages. Below, we highlight some key benefits of the sintered metal filters.
- Geometric Possibilities
The filter element found in a sintered metal filter makes sure that the geometric possibilities are near limitless.
It is only possible when done while making the sintered metal filter. During this period, you can influence the filter's design in any way you want so that it fits a required specification.
You can build mini filters and even complex filters that have irregular shapes by manipulating the die while production is in progress.
It is the die that creates the sintered metal filter.
- Fine Tolerance
This is another crucial benefit that one must not overlook. Fine tolerance is basically when you can carry out filtration without sparking any sort of reaction between the fluid and the sintered metal filter.
Although there is a general absence of reaction between the fluid and the filter, the type of metal utilized in creating the filter plays a huge role. The metal used in the filter determines what fluid it would not react to.
You need to select a filter whose metal does not react with the fluid it will be filtering because different metals react differently to various fluids.
- Corrosion Resistance
While filtration is in process, several mechanical and physical reactions occur. What the filter element in the sintered metal filter offers is a corrosion-free filtration.
The element in the sintered metal filter can resist all forms of corrosion. Having a corrosion-free filter means that the fluid comes out perfect after filtering. This is definitely a huge benefit.
If the sintered metal filter is not resistant to corrosion, it will affect the fluid and filtration outcome. Filtering with a rusted filter renders the process useless because the clear aim of filtering is to remove impurities, not add them.
- Filtration Efficiency
Filtration is basically separating the wanted fluid, either liquid or gas, from unwanted particles. When choosing a filter, efficiency should be a top priority so as not to compromise the whole filtration process.
The sole purpose of developing the sintered metal filter is to filter fluids at the highest efficiency level. You can actually adjust the porosity of the filter element for every fluid you are filtering. By adjusting the filter element's porosity, you increase the efficiency leading to contaminant-free filtrate.
Being resistant to corrosion also means that no metallic particle would be present in the fluid.
- Fracture Resistance
This advantage also spawns from the bonding of different metals and their respective physical properties.
Engineers bond these metals to harness their individual strengths, creating a filter that is resilient enough to handle tough conditions such as constant friction.
Sintered metal filters are polar opposites to other filters. The sintered metal filter is capable of handling tough conditions. Most of the other filter types are for simple filtering tasks, but the sintered metal filter takes the crown in terms of usability.
- High Thermal Shock
Thermal shock generally happens when there is a sudden fluctuation in the temperature, causing objects to suffer from stress. They build this filter to combat high thermal shock, making them a valuable cleaning asset.
This ability comes from combining different metals but keeping their physical properties. The manufacturing process is where their strength stems from.
Different metals react differently to temperature changes. Combining various metals with their different physical properties make the sintered metal filter perfect for absorbing high thermal shock.
Heat also interferes with fluids, altering its velocity and viscosity, and the ability to absorb thermal shock means that your filtration happens a lot smoother than you could ever imagine.
The ability of sintered metal filters to absorb high thermal shock makes them suitable for different thermal scales.
- Pressure Drop
Pressure drop simply refers to the pressure differential between two spots in a fluid conveying material. This simply means the change in the fluid's pressure between two spots on the material.
Every fluid filtration process requires a particular amount of force to carry it out. A little drop in the pressure can significantly alter the entire filtration process, leading to irregular filtration and fluid shortage.
The sintered metal filter is capable of - the required pressure to uphold maximum operation.
- Temperature and Pressure Resistance
Maintaining constant temperature and pressure while filtering is essential for maximum output.
By bonding different metals together, you retain their physical properties, including resistance to certain temperature degrees. The bonded metals make the filtering element perfect for high pressure and temperature situations.
This ability makes the sintered metal filter useful in lots of industrial processes. Chemical companies and gas plants are common industries that incorporate sintered metals in many manufacturing processes. Since they work with high temperature and pressure, the filters are the perfect fit to yield maximum results.
The process of manufacturing a sintered metal filter is not as tasking as you would think. Like all others, the whole setup starts from a point and ends in another, with each step followed accordingly.
To understand the metal filter's manufacturing process, you need to familiarize yourself with the sintering process and other things.
How Are Sintered Metal Filters Produced?
The production of a sintered metal filter is a three-step process which are:
- Acquisition of Different Metal Powders
Since the sintering process is all about turning powdered metals into end-use products, the first step involves acquiring the powdered metals.
You can obtain the powders by either grinding, atomization, or decomposition using chemicals. You can exclusively use the obtained powders or join them with another metal forming some sort of alloy.
The metals' physical properties remain intact after bonding, as it is a key feature for sintered metal filters.
- Casting the Powder in a Die
This involves forming the filter shape by casting the powder in a die. All you do is pour the heated powder in a die with the intended shape design. Then, you compact the metal properly before casting it.
The process requires high temperature and pressure so that the casted piece comes out with the proper shape. It is once again important to reiterate that the temperature applied does not reach the metals' boiling point.
The malleability of the metals used determines the amount of force used. The higher the malleability of the metal, the more you can induce pressure.
- Heating the Solid Piece
Once the formation is complete, the solid piece is transferred to a furnace where it is left under high heat. This heating process is the actual sintering where the metal particles bond together without being liquefied.
The result is a strong and rigid filter with proper porosity. You can change the filter's porosity to suit the fluid's flow pattern.
You must carry out these steps properly so that the finished sintered metal filter is not defective.
How Do Sintered Metal Filters Operate?
You do not need to be an expert to install and operate a sintered metal filter successfully. The working process of sintered metal filters is not as daunting as it may look.
Although most users find it challenging to determine its purpose, it is actually fairly simple and does not influence the filter mode of operation.
Since you can, without a doubt, adjust the filter's porosity to match the intended application, you must make sure that the filtration grade meets these three requirements to yield maximum results.
- Ability to retain contaminants
- Backwash ability
- Pressure drop
Checking these three requirements means that some vital factors must be heavily considered. You must consider the viscosity of the fluid you plan on filtering, the flow rate of the fluid, and the general attributes of the impurities you plan on filtering out.
The effectiveness of sintered metal filtration depends on the rising pressure drop. The pressure continually increases until it gets to the final pressure.
The fluid flow rate is also a deciding factor, thickening the impurities until they reach a point where the fluid's pressure drop will achieve the ultimate condition. The thickening effect lowers the pressure until it gets to the maximum pressure drop for a specific flow rate and viscosity.
The general attributes of the impurities include their size, density, and shape. You can carry out surface filtration when the impurities present are hard, regular-shaped solids that form dense cakes.
The backwash ability entails the addition of pressurized gas to the screen, simultaneously opening the discharge valve, allowing the backwash to occur.
The backwashing function enables the removal of contaminants from the sintered metal filter element. The process occurs through the generation of high momentary differential pressure.
Cleaning and maintaining the filter should follow the standard backwash process.
A uniform increase in the pressure drop rate shows an even distribution of the contaminants present in the filter. The effectiveness of the filters depends on the uniform pressure drop.
The fluid's temperature must be held at a constant degree. A slight temperature change will affect the viscosity of the fluid, altering the filtration process.
The change in viscosity leads to a rise in the pressure drop across the filter element.
To ensure that the entire filtration process occurs smoothly, you must sustain the filter's specific operating temperature.
Does The Sintered Metal Filter Come With Configuration?
The sintered metal filter comes with unique configurations. This is because you can design several filters to suit different applications. It all boils down to the nature of the fluid and the filtrate you require.
It is possible to obtain a filter design that reduces the backwash or blowdown process while increasing the throughput.
Several sintered metal filter designs are available for you to choose from. These designs include:
- Inside-Out Multimode Filtration
The process of filtering fluids occurs in the interior part of the open-ended tubular filter element (LSX and LSM)
Two tub sheets seal the entire system allowing the fluid to flow from the top or bottom of the designed inlet.
The inside-out multimode filtration can operate as a light contaminant filter or a high contaminant recovery filter. The light contaminant filter mode is vital for fluid filtration.
With a built-in side outlet made for the sole purpose of expelling contaminants, the multimode cross flow grants operational continuity.
It is also possible to filter in batches. This is possible when you cease the filtration process when it gets to the contaminant level.
When the filtration process is complete, you can then employ the backwash process in cleaning the filter.
The inside-out multimode filtration design has several benefits.
They use it mostly when specific gravity contaminants are present in the fluid. The upward flow mode makes this possible.
This build-up promotes contaminant removal at the highest level, and filter washing is fairly simple and straightforward.
You can also utilize single vessel filters if the flow rate permits it. This will allow you to pause the backwash process. For continuous flow, you can use dual sintered filters. This makes it easier to carry out maintenance jobs. You can make use of the three sintered filter for operational continuity.
- Outside-In Filtration
This system's design carries out filtration on the exterior part of the LSP, which is the closed-end tubular filter element.
If you intend to carry out continuous fluid flow operations, this system is excellent.
You can clean the outside-in filtration system using gas-assisted hydro-pulse backwash. Backwash cleaning means that you proceed with the filtration process without having to worry about impurities present in the fluid.
- Inside-Out Filtration
Unlike the outside-in filtration system, the inside-out filtration occurs on the interior of the LSI, which is the closed-end tubular filter element.
Maintenance and cleaning are fairly easy. You can clean it using different backwash techniques. Empty shell slurry, full shell slurry, and empty housing wet cake discharging are the backwashing techniques available.
These techniques are excellent if faced with situations where the pollutants in the fluids are flowing with significantly low velocity.
With the inside-out filtration system, it is a lot simpler to get rid of pollutants. The outside-in filtration is the polar opposite of this system, where the outside-in filtration system is a complex structure, while this is a simple structure.
It is also possible to switch filter elements to match a particular pollutant, with its physical attribute considered. For example, if you are filtering a fluid with large-sized contaminants, you can select a filter element with an average pore size. However, if you are filtering a fluid with tiny particles flowing in it, you would want to opt for a filter element that has tiny pores.
By doing this, you can get rid of all the pollutants flowing in the fluid, which ultimately leads to maximum output.
Another advantage of the inside-out filtration system is that pollutants exit the element through the upper filtrate outlet.
How Do I Clean My Sintered Metal Filter?
Maintenance and cleaning is an important aspect of extending the lifespan of your filter. Scheduled cleaning operations are set up to make sure that the filtration system does not fail during use.
The cleaning process is fairly straightforward and not at all time-consuming. You can follow these steps to clean your sintered metal filter properly.
- Note the sintered metal filter's differential pressure.
- Place the sintered metal filter inside a 380 degree Celsius nitrogen protection furnace.
- Keep the sintered metal filter in the furnace for 2 hours.
- Clean the sintered metal filter properly by placing it inside an ultrasonic machine, simultaneously heating it for 30 minutes.
- Clean the porous sections of the sintered metal filters to avoid pollutants coming from the inside. You can use continuous fluid flow to get rid of these pollutants.
Removing solid particles is what people find complicated in terms of cleaning the filter. This is because some particles can hide in the pores, and once there, they are difficult to remove. The best way to remove them is by reverse flushing, redirecting the fluid to get the particles unstuck. This action is what we call backwashing.
If backwashing proves difficult, then you can use either a vacuum hose or simply dunk the filter in a fluid.
Dunking the filter is a fluid that makes the contaminant present to absorb the fluid. You should do this repeatedly to increase your chance of getting rid of the contaminants.
When cleaning a sintered metal filter, make sure that you follow all guidelines. Do not manhandle the filter to avoid breaking the parts apart.
Types of Sintered Metal Filters
The market is home to several types of these filters. It all boils down to what you want to use the filter for.
The intended application dictates what type of filter you would purchase. Here are some of the types of sintered metal filters available for purchase.
- The Pleated Sintered Metal Filter
As the name entails, the filter comes equipped with pleats that carry out the task of filtering any fluid.
The pleated sintered metal filter's design is one of a kind. Its large surface area is capable of filtering a lot of fluids. They are easy to use and clean, so maintenance does not pose any form of issue.
The pleated sintered metal filter has its separate components assembled together. These individual parts come together to form the trademark cylinder shape.
The filter's housing is also built like a cylinder, holding all the pleats, while the exterior comes with slots whose width defines the filter's pore size.
The pollutants exit from a slot built on the filter. You can adjust the size of the sloth to allow for proper contaminant removal.
- Sintered Porous Metal Filter Element
These are simple filters with pores that do the filtering. They are capable of withstanding high pressure and extreme usage.
Their manufacturing process, unlike the pleated sintered metal filter, is rather complex.
They build the filter using plastic that undergoes the sintering process. This is after employing a high molecular mass thermo-polymer powder. The cryogenic ground powder is strictly monitored during the manufacturing process
The filter can filter fluids while keeping contaminants with dimensions between 5-200 microns.
Depending on the pore size and the nature of your filter (its filtration attributes), the sintered porous metal filter element can induce up to 70% pressure drop.
These filters are common in areas where the temperature they work with does not exceed 80 degrees Celsius.
Working at temperatures higher than the recommended temperature is not ideal, to say the least. You are slowly destroying the filter element without even knowing it. You would only find out during routine maintenance checks, or when the filter eventually collapses.
How Well Can the Sintered Metal Filter Sustain Pressure?
If a filter cannot sustain the required pressure needed to complete the filtration, it means that the filter is faulty.
Many types of filters cannot handle high pressure, but the sintered metal filter is capable of this feat.
Once the required operational pressure drops, the liquid can no longer flow through the filter, leaving contaminants in the fluids.
The right filter reduces the risk of failing as a result of a drop in operational pressure
How Can I Tell if I Bought the Right Filter?
Differentiating between standard and substandard sintered metal filters is an important task. You can only trust quality made sintered metal filters because cheap knockoffs can fail at any point in time.
Standard sintered metal filters have key distinguishing features that separate them from cheap knockoffs.
Below are some of the distinguishing features to look out for when buying a sintered metal filter.
- Custom Pore Size and Flow Attributes
The filter grants you the ability to alter the size of its pores. Other filter types do not allow such luxury.
You can alter the filter's pores depending on the fluids' property and the contaminants' physical attributes.
It is also possible to alter the velocity of the fluid on your screen. You can also change the filter's position with which the fluid flows.
If the fluid flows from left to right, or from top to bottom, you can position the filter in that way to match the flow pattern.
- Temperature Resistance
The sintered metal filter is capable of withstanding extreme temperatures. This is a vital feature that makes people incorporate it into their processes.
During the manufacturing process, engineers combine metals with good temperature resistant properties to produce a sintered metal filter that you can use for high-temperature operations.
When seeking a sintered metal filter, you should consider the temperature range so you don't select a filter that will fail during filtration.
- Corrosion Resistance
Corrosion is a bad thing when it comes to filters.
Mechanical and chemical reactions can cause a filter to corrode.
If your filter corrodes, it not only means that the filter would fail. It also means that your filtration would not be effective.
Sintered metal filters do not face any corrosive threats. This is also because of the combination of different metal powders.
The inability to corrode makes the sintered metal filter suitable for all applications. Metal particles do not enter the fluid during filtration, and the entire process is efficient.
- Volume
By volume, we refer to the contaminant holding capacity. This determines how long you can continue filtering before the filter is full and can no longer hold particles.
The contaminant holding capacity differs from filter to filter, and it all comes down to the intended application.
For larger purposes, you would need a filter that can hold a lot of contaminants, while for smaller purposes, you can use a filter with small contaminant holding capacity.
- Filtration Precision
You can carry out precision filtering because of the ability to adjust the filter's pore size while operating.
For finer filtration, you can adjust the pore size to be minute.
For simple contaminant removal, you can adjust the pore size to match the dimension of the contaminants. That is the average pore size for average filtering.
- Filtration Grade
You can customize your filter to your taste. This means that you can upgrade the filtration grade from 0.1 microns all the way to 200 microns.
The filtration grade shows you how fine your filtration would be, and it is all possible because of the peculiarity of the sintered metal filter
- Physical Durability
The sintered metal filter is extremely sturdy. This is why people tend to use them for tough operations.
Its physical strength is due to the various metals bonded together. These metals retain their individual physical properties even after the bonding process is complete.
The combination of the physical strength of the bonded metals makes the sintered metal filter extremely durable. You can use a single filter system for a long time without feeling the need to replace it.
- Welded Filter Element
Welding the sintered metal filter element offers a ton of stability. Welding is far better than screwing the parts together. Vibration constantly affects screwed parts, leading to the filter coming undone during or after filtration.
Additionally, screwed parts pose a form of liability because they need consistent maintenance required and can affect productivity. Using a fully welded sintered filter element means that you can reduce the need for constant maintenance.
Welded parts have limited motion when subjected to constant vibration. Having a fully welded sintered metal filter rather than a screwed one means that you can continue filtering for as long as required.
- The Material Used in Manufacturing
An important feature to look out for when purchasing a sintered metal filter is the material used.
When buying a filter, you want one that would last for a long time. This all boils down on to the material the filter is made out of. The materials refer to the different metal powders that join together through thermal bonding.
Bonding different metal powders means that you can get a wide variety of filter elements. These elements still possess the physical properties of the metals they are made out of.
What Are The Materials Used in Making Sintered <etal Filters?
As the name suggests, the sintered metal filters are made mostly out of metal. There are a lot of metals and alloys available for constructing sintered metal filters.
You can select a combination of these metals to make your own sintered metal filter.
These metals must be able to withstand high temperatures and must be strong enough to withstand mechanical force. This will ensure that the filter remains in proper working condition.
- Filter Cartridge
The main component of the sintered metal filter is its cartridge. The role the cartridge plays is extremely vital, and you should never downplay its role for what so ever reason.
The cartridge is where the filtration magic happens.
They design the filter cartridge with the sole purpose of withstanding the toughest of contaminants. Its durability is impeccable and second to none.
When you buy a quality sintered metal filter, you are confident of the cartridge's working performance. A quality cartridge means that your filtration efficiency is optimal.
You get your money's worth for every standard sintered metal filter you purchase.
- Filter Disc
Buying a standard filter means that all the components are quality components. The filter disc is no exception.
The filter discs have metal as their main constituent, just like the rest of the filter components.
The filter disc holds the pressure gathered during filtration. It is far more durable when compared to other types of filter discs. For other types of filters, their filter disc often crumbles after being repeatedly subjected to pressure.
The strength of the filter is a key factor in its efficiency.
- High Permeability
In any filtration unit area, the pressure drop measurement of the fluid at a specified flow is the fluid's permeability.
These filter's high permeability is a key feature in their functioning.
In essence, for you to properly filter any fluid, you need to make sure that the fluid's temperature and the pressure drop match.
The permeability differs from filter to filter. All you have to do is find the one that matches your intended application.
Where Can You Apply Sintered Metal filters?
You can install a sintered metal filter in any place that demands the presence of a filter. However, many areas specifically require the installation of a sintered metal filter. The sintered metal filter in your possession might even be good enough to use in another area.
Many industries apply sintered metal filters in a couple of their processes. As a matter of fact, some industries use sintered metal filters exclusively because of their operations' nature.
Here are a few industries that demand the installation of sintered metal filters.
- Gas Plants
Gas plants use sintered metal filters because of their temperature resistant ability.
Another reason they use sintered metal filters is that the metals in the filters do not react with the gases. You can produce different gases without worrying about the effect the gas would have on the filter.
- Food Companies
Here, they use the sintered metal filter to collect juices and nutrients. Since the filters do not react with consumables produced, it makes them prime material for filtering nutrients.
The sintered metal filter provides efficiency, so you do not need to worry about substantial shortages in your foods and beverages. The quality of the foods and drinks remains untouched, which is a positive sign, given the industry's peculiar nature.
- Chemical Industry
The chemical industry is one of the industries that extensively use sintered metal filters due to the nature of their processes.
Since the sintered metal filter is corrosion, temperature, and pressure-resistant, it is a valuable item in filtering chemicals. The chemical does not affect the metal, and contaminants due to corrosion do not enter the chemicals.
The sintered metal filter can also withstand the high temperature and pressure associated with the different chemical processes.
- Power Plants
Hydroelectric turbines run non-stop to produce constant electricity. A stop in operation means that power generation is has ceased and is now at the zero marks.
Turbines and solid particles moving in between its parts is a bad combination. These contaminants are capable of destroying different parts if left unchecked.
If a part of the turbine spoils, there would undoubtedly be a break in power generation. You can easily prevent this by installing a sintered metal filter to keep the solid particles out of the turbine.
Since the sintered metal filter does not corrode, you can install it long-term, with routine maintenance being the only requirement.
Installing a sintered metal filter means that you increase the overall working performance of the turbine.
- Petroleum Plants
The petroleum industry is peculiar. You require extreme temperatures to refine and produce petroleum and other by-products. Petroleum plant workers use sintered metal filters to filter specific products from others.
The sintered metal filter is ideal for these operations because it does not affect fuel quality. This is because the filter does not chemically react to the fuel.
Workers can carry out all filtration processes without having to worry about contamination and filter failure due to extreme temperatures.
In conclusion, if you need a quality filter that is both long-lasting and efficient, purchasing a sintered metal filter is a step in the right direction. These filters are extremely versatile, and as mentioned earlier, you can use them in a wide variety of areas.
You need to, however, equip yourself with the knowledge required to handle these filters properly. They may be stronger than other types of filters, but managing them with care is a good way of showing professionalism.
