Sand filter shopping guide
Sand filter is one of the main equipments for removing and reducing suspended particles in water, which are widely used in industrial sectors and swimming pools. These filters have a very high variety in terms of performance, capacity and body material and price, and based on the type of application, the appropriate option should be selected. Due to the great variety of these types of filters, in the following, we will provide a guide for buying sand filters for swimming pools and industrial environments
What is a sand filter?
The design and construction of many equipment and devices used in water and wastewater treatment is inspired by the behavior of nature. Sand filter is one of the cases that its function is completely based on nature and by fine grains of sand, particles suspended in water are separated. The function of this type of filter is that water containing suspended particles, mud, etc. is passed through the sand bed. Particles suspended in water are not able to pass through the grains of sand and clear water comes out of the bed. This behavior is quite similar to the passage of muddy water over soil and sand layers in nature and is used in the water treatment industry due to its high efficiency and low cost for implementation.
Sand filter is equipment with a metal or fiberglass tank in which a bed of silica grains and sand is considered inside of it. These filters have inlet and outlet valves and water containing mud and suspended particles enter it and exit after clarification.
Buy sand filter by type
One of the most important factors to consider when buying a sand filter is the type of filter and how it works. In general, sand filters can be divided into the following three groups based on how they work:
- Slow sand filter: Water enters the filter tank without any lateral pressure and the process of separating suspended particles is performed very slowly. Water treatment with this type of filter requires a lot of time and is not suitable for industrial applications.
- Gravity sand filter: Gravity filters are very similar to the slow and quiet type and the only difference is the size of their sand and silica bed. By reducing the size of these substrates, the rate of separation of suspended particles in the water by the filter increases to a relatively desirable level. This type of sand filter is cost-effective and has a faster speed than the slow type, but its silica grains get dirty faster and need to be washed frequently.
- Rapid (pressure) sand filter: If the purpose is to buy a sand filter for industrial environments and water purification of pools, fast and pressurized filters are the best option. In this type of filter, water passes over the silica bed with high pressure by the pump, and for this reason, the clarification speed in them is higher than the previous two options. Compression sand filters are mostly used as pre-treatment in reverse osmosis equipment.
Buying the standard capacity for sand filter
Another very important issue to consider when choosing and purchasing sand filters is their capacity. The tank size of each of the filters has different sizes and should be selected according to the type of application and the amount of inlet water flow. The capacity of the filters is calculated according to the volume of water that must be treated per hour. Purchasing a sand filter with a capacity less than the inlet water flow will cause a lot of damage to the device and will not provide the necessary efficiency. In contrast, it is better to choose a tank size slightly larger than the desired flow and capacity. In this case, the speed of clarification and water purification will increase and less damage will be done to the device.
When buying or ordering these filters, it's enough to tell the seller the volume of pool water or boiler, etc. to offer a sand filter with an ideal and suitable capacity.
Paying attention to the body material of the sand filter
One of the most important factors in choosing any of the water treatment products is to pay attention to their body material and the body material of the sand filter is directly related to their resistance and durability against environmental conditions and pressure. In addition, you should pay attention to the fact that the body of the filter should be resistant to corrosive substances in the water and won't make cracks and corrosion on their surface over time. When buying a sand filter, you will face the following options in terms of their body material:
Metal sand filter
One of the best choices for industrial environments where water enters the filter tank with high pressure and a lot of pressure will enter the body of the device, is a metal sand filter. These filters have several subsets and include different types of steel and galvanized sand filters. Steel sand filter, which is an alloy of steel and is completely stainless, has a high resistance to solutes in water and has a high durability.
Fiberglass sand filter
Fiberglass sand filter is an ideal choice for buying sand filters for water treatment of indoor pools and stadiums. The body of this type of filter has a good resistance against water pressure and has a good capacity for water purification with medium and low capacity, durability and durability.
Buying sand filter based on application
Another very important issue that should be considered when choosing and buying sand filters is the suitability of the filter with the type of application. Sand filters have many applications and are used for agriculture, pool water treatment, boilers, desalination plants, etc. The most practical types of sand filters are the following options:
This type of filter has a fiberglass body and is much smaller than the industrial type in terms of size and dimensions of the tank. These filters have many subsets in terms of capacity and small samples are used for indoor pools.
In industrial environments, metal and steel sand filters are the most widely used and their body thickness should be such that they can withstand the pressure. In addition, the filters used in industry are pressure type and water enters the tank with a high speed pump and separates the suspended particles in a short period of time. In a general comparison, industrial sand filters are more resistant in terms of body material than pool filters and have a higher water purification capacity and speed.
Price of sand filter
Another important factor to consider when buying and choosing a sand filter is the price. The price of a sand filter is determined based on several important factors, including body material, tank capacity, and type of filter (pressure, slow, gravity). That's why industrial filters are always more expensive than the type of pool and home water purifier.
In addition to the above, it is necessary to pay attention to the silica material used in the filter and their purity. The use of poor quality silica causes the filter to need to be washed at short distances and will eventually lose its efficiency. In order to avoid reducing the efficiency of the device, it's better to use high purity silica substrate and reverse wash them at the appropriate time.