Candle filters are an approach for removing fine particles. A candle filter contains multiple mesh candles in the same dimension, which are placed on or screwed on, parallelly. Thus, a large filter area is created for a low construction volume. They are usually suspended like candles in the flow stream, the gas passes through them forming a cake on the surface which is then periodically back-flushed to remove the trapped material.
Candle filters require frequent maintenance. Because of particle build-up and the resulting reduced flow rates, filters must be cleaned with a soft brush and clean water every 2 weeks. After successive cleanings, the candle tends to lose wall thickness and becomes less effective for removing microbes. The service life of candle filters vary, but they should be replaced every 6-12 months.
Operation and precautions during cleaning:
When cleaning the candle filter, the liquid inlet and outlet ports should close first. And the compressed gas should introduce into the tank body, and then the residual hydraulic pressure in the filter tank body is filtered. When the filter column backwash, compressed gas inflation filter cloth introduces at the outlet of the filter filtrate. So that the intercept impurities are separated from the gap of the filter cloth and discharge through the lower discharge port of the filter element.
How does the candle filter element works?
The candle filter can filter solid particles and colloidal substances and other pollutants in the working medium. Thereby effectively controlling the pollution degree of the working medium to ensure the normal operation of the system. The filtrate enters the filter through the inlet of the candle filter. After the impurities are intercepted by the filter element, the filtrate flows out from the outlet and then enters the clear liquid storage tank. As the filtration progresses, the cake layer is continuously thickened and the filtration resistance is continuously increased. Therefore, when the set pressure difference is to reach, the filter element needs to backwash.
Candle filters mainly using for oil filtration. In use, a plurality of filter elements and a magnetic disk are usually using in combination, and the filter element is of the same size so that the filter area is effectively increased. The main feature of the candle filter for ships is high temperature and high pressure, and the pressure difference can be greater than 10 MPa.
Candle filter use precautions:
1. The oil before the candle filter enters the engine is new oil, not the circulating oil regenerated by the filter oil machine that has been used many times before.
2. Reasonably match the filtering accuracy. Common precisions are 20 microns, 30 microns, 40 microns, 80 microns, and the like.
3. Select the correct candle filter connection method.
4. Select the filter element size according to the filter flow.
5. choose a high-quality filter layer, high strength, accurate accuracy of the candle filter
6. Regular backwashing and backwashing can effectively extend the service life of the candle filter.