Filtration Equipment
Filtration equipment removes solids from liquid. This is done by pushing liquid through a porous surface under a certain pressure.
Some of the more common types of filtration equipment include filter presses, filter plates, and filter cakes. Other types are clarifiers and deep bed filters.
Pressure Filtration
Pressure filtration is an effective technique for removing suspended solids from water. It is used for both municipal and industrial water treatment, as well as for water recycling. It is often placed after clarification, flocculation or physical-chemical plants and can also be combined with a sterilisation section to treat domestic waste water.
These systems are typically operated manually, but can also be controlled automatically using a programmable logic controller (PLC) or microprocessor in combination with a pressure meter. Filtration is most commonly done by sand filters, although some filter systems use activated carbon for pollution reduction.
The sand bed is usually covered with a thin layer of plastic or glass-reinforced plastic (GRP) that can be removed for cleaning and maintenance. The sand filter is connected to a piping system that directs and controls water flow during treatment and backwashing operations.
In the filtering process, a sand or other filter medium (typically a synthetic filter media like polypropylene) is saturated with water and forced under high pressure to a specific cake resistance, which gradually increases as filtration occurs. The specific cake resistance is an important indicator of the pressure filtration resistance of a filter medium, and it can affect the filtrate mass flow rate.
Because pressure filtration is a liquid filtration process, the effects of liquid properties on filtration performance need to be evaluated and understood in order to develop a practical filter design. For this purpose, a computational fluid dynamics (CFD) and discrete element method (DEM) model was developed to simulate the effect of solvent flow through a solid particle cake in a filtration chamber.
To validate the model, we performed flow tests on deionized water and a mixture of monodisperse spherical glass beads using varying operating conditions and applied pressures. The resulting values were compared with those obtained from experiments to determine the effect of particle properties and liquid properties on the specific cake resistance, filtrate mass flow rate and other relevant filtration parameters.
The simulation results indicate that the filter medium resistance Rm is directly proportional to the liquid viscosity. This result suggests that, unlike other filtration processes, the viscosity of the liquid affects the specific cake resistance and the filtrate mass flow rate in pressure filters. It may also influence the overall filtration efficiency of the pressure filter system by changing the filtrate mass flow rate and the total filtering time.
Vacuum Filtration
Vacuum filtration (also known as reduced pressure filtration or suction filtration) is a laboratory technique used filter-equipment to separate liquids from solids. It involves the creation of negative pressure in the container under a membrane or porous material, accelerating liquid to pass through the membrane and separate solid from liquid.
A variety of filtration equipment is available to perform vacuum filtration. Some common items include a vacuum pump, safety trap, filter holder and receiver flask.
The pump should be able to create a vacuum of at least 50 mmHg, depending on the type of sample and its viscosity. Generally, more viscous or more impurities samples require higher vacuum levels to obtain satisfactory results.
If the sample is to be filtered by suction filtration, connect the side-arm Erlenmeyer flask with a rubber sleeve and a Buchner funnel (Figure 1.75a). Then place a piece of filter paper in the funnel that is small enough to remain flat but large enough to cover all the holes in the bottom.
Make sure that the filter paper fits well into the funnel because if it does not, the solvent will clog the pores in the filter paper. This is very important, because the solvent will suck out of the filter paper as it passes through the filter.
After the filtration is complete, remove the filter paper and rinse it with cold solvent to help get rid of any impurities that may have been dissolved in the filtrate. Then, set the filter cake on a watch glass and allow it to dry for a while.
There are many different types of rotary drum vacuum filters. They range in size from small, benchtop units to large, floor-mounted ones. These can be constructed in various metals and plastics and can handle corrosive materials.
In the past, most rotary vacuum filters were made of stainless steel. Now, they can be made in a variety of other materials, including plastics and rubber for handling corrosive materials. They also can be made with internal piping and valves that are designed to withstand the conditions of vacuum operation. These improvements have resulted in more efficient operations and fewer shut-downs.
Sand Filtration
Sand filtering is a popular water treatment method, which removes suspended solids from wastewater. It is a relatively cheap and efficient system that can also be used for home water purification. It can eliminate bacteria, viruses and protozoa, among others.
It is an environmentally-friendly filtration method that has been used for over 150 years and is still commonly used in some areas today. The process involves percolating contaminated water through a layer of sand that is 60 to 120 cm thick. The water passes through the sand bed at a slow flow rate of 0.1 to 0.3 m3/h. The water is then allowed to remain in the sand bed for a few hours and larger particles are allowed to separate from the sand.
The effectiveness of the sand filtering process is dependent on a number of factors. The amount of sand, its grain size and the speed of water flow through the sand bed all play an important role in how effective it is.
This type of sand filtration is often used in industrial environments. It is designed to remove a wide range of contaminants from water including microorganisms, particulates and turbidity.
Sand filters are available in many different sizes and designs. A typical design consists of a tank with a sand bed and nozzles. The water flowing through the sand bed is filtered by the nozzles. The sand grains in the sand bed will stop particles of greater than 100 microns.
As a result, the sand filter is capable of removing contaminants such as sediment, bacteria and fungi from wastewater. This makes it an excellent option for removing a variety of contaminants from industrial wastewater.
In addition, sand filters can remove dissolved iron and manganese from wastewater by oxidation and filtration. They can be fitted with a specialty manufactured filter-equipment filter media, which is able to reduce these metals from the wastewater stream.
It is important to note that the sand filters need to be cleaned periodically. This can be done by backwashing, which involves increasing the water flow in the opposite direction to the original one. This will help to remove polluted sand and return it to the filter for reuse. This is an essential step for the long life of sand filters.
Filter Press
A filter press is an industrial tool that uses pressure filtration to dewater and separate liquids and solids. Various types of filter presses are used in different industries. These include plate, recessed chamber filter presses and membrane filters.
A slurry is pumped into the filter press and is subjected to high pressure for dewatering. As the pressure builds, slurry solids begin to build up within the hollow chambers and eventually form a filter cake. When all the chambers are full of a filter cake, the slurry feed pump is stopped, and the filter cake falls out by gravity.
This type of sludge processing can be used to dewater sludge for disposal or secure landfill or it can be used to produce a dry cake that is suitable for direct use in a process. The filter press is a highly reliable piece of equipment that can be operated for long periods without any downtime.
Filter Presses are primarily used for liquid-solid separation in industrial applications. They are one of the most versatile pieces of equipment for this purpose. They are available in a wide range of sizes and capacities to accommodate the specific requirements of each slurry.
The basic filter press consists of a skeleton with alternating plates and frames that are lined with filter cloths. The skeleton and the filter plates can be made from either stainless steel or polypropylene materials.
Each alternating plate has a narrow slot that allows the filtrate to flow through the filter cloth and out into a collection system. The filter cloths can be a mesh or a porous material.
As the slurry is pumped into the filter pack, it passes through the mesh or the porous material in the filter cloth and the clean filtrate water is separated from the solids. This clean water exits the filter pack through a series of corner ports and into a manifold. Once the correct valves in the manifold are open, the clean filtrate is discharged out of the press through a single outlet.
A membrane filter press is a modified version of the filter press that uses membranes to squeeze excess water out of the slurry and reduce the time it takes for a cycle to complete. These machines also have lower water usage and power consumption than other filter presses, which can make them more economical to operate.
