How are Haimi’s automatic backwash filters cleaned?

They are divided into cylindrical type and tube-type; we chose the cylindrical type, which is relatively more expensive； For domestic production, there are also Beijing Antai, Xinxiang Shengda, etc ； Filtering is primarily carried out using metal sintered mesh or wedge wire filters (Johnson filters). Periodically (every 8 hours or so), or when the pressure difference reaches a set value, solenoid valves are used to change the flow direction of the medium, allowing for self-backflushing into the dirty oil tank, after which nitrogen is used to expel the oil. Sintered mesh is rarely available in China; the technology behind it comes mainly from Pall in the United States. Companies in China such as Haimite use wedge-shaped wires. The specific operation method is as follows: Under normal operating conditions, the raw material medium enters the filtration container through high-performance sealing valves. As filter cakes gradually accumulate on the surface of the filtration elements, the effective filtering area of these elements decreases, which results in a pressure difference between the two ends reaching a predetermined value. The differential pressure transmitter outputs a signal, and the PLC controller sends signals to the actuators of various valves according to the programmed instructions. First, open the inlet and outlet valves of the feed material for the backup filter (such as Group B); Group B is put into normal operation. The PLC controller then closes the inlet and outlet valves of Group A, switching Filter A to reverse flushing mode. The reverse flushing force generated by nitrogen pressure is used to quickly remove the impurities accumulated on the surface of the filtering elements. After discharging the dirty oil, close the compressed gas inlet valve and the drain valve. Once container A is filled with crude oil, it automatically enters standby mode. The flushing time can be adjusted based on the effectiveness of the flushing process (determined by observing the pressure recovery from the pressure transmitter). When the pressure difference after flushing the filter system with nitrogen is not satisfactory, the PLC program automatically switches it to the oil immersion mode; the immersion time is adjusted based on the effectiveness of this process (usually set at 2 hours), and then backwashing is carried out again with the aid of gas to remove the filter cake accumulated on the surface of the filter elements in the most efficient manner

The backwash filters in our workshop are from Haimite; currently operations have been halted for repairs, and we are preparing to take one apart for inspection. In my opinion, whether a filter gets dirty depends mainly on the type of material being processed and the volume of processing. When dealing with coker diesel and gasoline, it becomes easy for the filter to get dirty; straight-run diesel is less likely to cause this problem

Haimit’s filter tube type is more useful than the barrel type

The filters produced by Heimit include tube-type and cartridge-type filters, each with its own advantages and disadvantages. Currently, the tubular type is still the most commonly used, mainly because it is easy to install and simple to operate! Tubular types are mainly suitable for filtering raw materials with large throughput and low operating pressure. Their advantages include a compact structure, small footprint, and low amount of contaminated oil.