The concept of filtration is one that is taught worldwide. Filtration is the process of separating two substances into filtrate and residue. The filtrate is the impurity-free substance, either liquid or gas, while the residue is the discarded contaminant – dirt, grime, dust, bacteria, minerals, or chemicals affecting the quality of the solution.
When you are looking at the concept of liquid filter, the areas of application are vast. Liquid filtration applies in areas such as the chemical industry, wastewater companies, recreational parks, etc. Filtering liquid basically involves removing impurities and solid particles from the liquid itself.
In today's article, Saifilter industrial filter manufacturer will be discussing nine vital factors you should consider when choosing liquid filtration systems.
1. Liquid Filtration Quality
In the general sense, filtration is a process by which you separate impurities and particles from a medium, either liquid or gas, using a filtering medium.
When carrying out filtration, you are either trying to:
- Separate gas from liquid: Getting rid of the bubbles present in the liquid
- Discard liquid from gas: Removing any trace of liquid that might interfere with the gas and its use through any suitable means
- Remove solid particles from either liquid or gas
The quality of filtration should be a key requirement when you are trying to filter any liquid. Before you begin the filtration process, you need to consider the nature of the particles and their dimensions, as well as the nature and size of the filtered material.
Particles differ in dimensions. Microns are the measurement for the dimensions of a particle, which determine what filter is suitable.
Solid particles measured to be one micron or larger tends to float on liquid medium, while solid particles smaller than one micron in dimension always sink to the bottom of the liquid
Gelatinous solutions, best referred to as colloidal solutions, carry particles that range from 0.01 to 1 micron in dimension.
Removing coarse particles requires a technique that is different from the one used in removing fine particles floating in the liquid. Therefore, any solution carrying different size particles would require a different type of filters to remove them efficiently.
2. The Right Filter for the Particular Purpose
Engineers build different filtering systems for peculiar filtering operations. There are smaller filtering devices for small scale operations and larger ones for complex industrial processes.
For example, to filter liquid surfaces, you need a filter that can retain fine particles smaller than one micron. Depth filtration, on the other hand, uses filters capable of scooping large particles that settle at the bottom of liquids.
Surface filters need regular cleaning and maintenance. This is because they perform extremely delicate jobs and require all the care they can get. Depth filters do not require as much maintenance work as surface filters do. They do require more labor because of their overall size and holding capacity.
Depth filters require frequent replacement of clogged parts to keep it running smoothly. On the other hand, a surface filter needs more cleaning sessions than part replacement sessions.
Depending on the nature of the situation, industries can choose between employing reverse osmosis, cartridge, or bag filters. Each of these filtration solutions offers unique benefits, but have their own drawbacks.
- Reverse osmosis: Reverse osmosis produces highly purified water. Examples of industries that use reverse osmosis in producing purified water include; pharmaceutical companies, cosmetic companies, food processing companies, and households.
- Cartridge filters: Cartridge filters are simple filters used in removing certain chemicals and solid particles. Cartridge filters fit into cases that act as their housing. Water purification industries often use during the final stages of filtration.
- Bag filters: Bag filters, also referred to as bag-house filters is an industrial grade filter. Bag filters are usually made out of fabric mesh. The primary purpose of using a bag filter is to clean fluids with small amounts of solid particles. Bag filters are attached to pipes, and operators use the bag filter's housing to secure it to the pipe.
3. Continuous Filtration or Batch Filtration?
The mode of filtration depends on the peculiarity of the task. Some industries often seek help from filtration companies as they specialize in filtration. To maximize efficiency, operators must use the right filtering pattern.
There are two categories that filtration devices fall under. These categories are:
- Continuous filtration: This process of filtration allows for continuous filtering, eliminating the need for breaks in the filtration process. Companies that run long term operations usually result in this process because they can clean and purify their liquids without stopping. Maintenance and cleaning operations happen after completing the filtration process
- Batch filtration: This involves carrying out filtration processes in batches. Batch filtration allows for faster and easier cleaning and replacement of damaged parts.
4. Safety Risks and Hazards
Operators should be able to determine whether the filtration media and liquid are compatible. Industries should strictly follow and maintain all safety precautions and guidelines provided. These safety guidelines are put in place to reduce industrial injuries and environmental pollution that can threaten plant and animal species, and even humans.
In conclusion, there are many factors to consider when choosing a filter or a filtering technique. You should be able to tell what filter to use when filtering certain liquid solutions to produce efficient results. You can damage machines by using the wrong filter type. Overall, you can cut down on cost and risk by using the appropriate filter and filtering agent.
5. Conditions for Using Strainers or Filters
Industrial grade filters must be able to withstand high pressures and temperatures. Filters range in grades, and this factor is vital in choosing the right filter. Industries use either filters or strainers depending on the situation.
High-grade industries use strainers more than filters. Pipelines and processing plants are common industries that employ use strainers more often. This is because of the high pressure and temperature their operations create. Strainers are best suited for this type of job.
Basket strainers are a common industrial filtering device. Four materials are primarily used in making basket strainer. These materials include:
- Carbon steel: The oil and gas industry uses carbon steel strainers in their delivery pipes. This is primarily because carbon steel provides high-temperature resistance and has a high yield strength.
- Stainless steel: Industries that deal with corrosive materials make stainless steel strainers as their primary filtering device. Pharmaceutical, food processing, cosmetic, and chemical companies are a prime example of industries that make use of stainless steel strainers.
- Bronze: Only certain industries make use of bronze strainers. They offer low-temperature resistance compared to stainless steel and carbon steel strainers.
- Iron: Iron is cost-effective and provides significant corrosion resistance. Iron is a good raw material since it is able to withstand high temperatures and pressures. Water companies often use iron strainers.
Foam, cloth, and mesh are the primary material used in making regular filters. These materials offer low resistance to high temperatures and pressures, but their ability to discard fine particles is extremely high. Wastewater companies often use filters during the last stages of water purification.
6. Operating Pressure
All filters come with a maximum rating for their pressure of operation. This rating tells the user the maximum amount of pressure the filter can withstand before failing. Filters do not carry a minimum operating pressure rating. This is because they can function at low pressure, experiencing little to no stress. For automatic, self-cleaning filters, it is important to always remember their maximum operating pressure to reduce the risk of operation failure.
7. Maximum Flow Rate
The liquid's flow rate determines the filter suitable for the filtration process. Operators should always check a filter for its maximum operating flow rate to match it with the system. For example, a filter with a maximum operating flow rate of 200 GPM will not work for a system operating at 500 GPM. The filter can not accommodate the fast flow of the liquid, and hence, filter failure is inevitable.
8. Pressure Drop
Pressure drop is simply the difference in the total pressure experienced between 2 points in a material carrying fluid, like a filter. Think about it this way. When you are trying to filter a liquid, you force the fluid to flow in the direction of the filter. Once the liquid reaches the filter, it changes direction as it tried to flow pass, creating some form of resistance. The resistance created causes the pressure to build up in the receiving side of the filter while the pressure of the liquid drops once it passes through the filter. Several contributing factors determine how low the pressure drops. These factors include particle size, filter media, liquid's flow rate, and viscosity.
What is so important about knowing the pressure drop? It is very important to know the pressure drop because the desired flow pattern changes when pressure builds up and exceeds the filter's maximum operating pressure. The filter also clogs quickly, and in some drastic situations, the filter inevitably fails.
9. Cost of Replacing or Cleaning the Filter
Self-cleaning filters normally backflush particles from their surface, reducing the labor involved in different kinds of filtration.
You must also consider the costs involved in disposing of used filtration apparatus in the total operating cost of the industrial filter that you choose. For instance, it is less expensive to replace a bag filter than cartridge or reverse osmosis filters.
Strainer filters are normally used for protecting mechanical devices like pumps from the damage of particles. They don't wear out as fast as mesh or fabric filters. However, they need to be frequently cleaned, which should be an important factor for companies with few hands available to take on this duty.
Hence, you must consider the costs of:
- disposing of waste filters
- downtime and labor while filters and cartridges are being replaced
- manual labor to clean the filter