Miller Magazine Issue: 147 March 2022

80 COVER STORY MILLER / march 2022 ergy in the mill after roller mills and pneumatic fans. This energy is consumed during the production of com- pressed air to be used to clean the filter bags. The pow- er required for compressed air production is calculated by Formula (1). Here; P is the consumed power (W), μ is the efficiency of the system (isothermal), p1 is the absolute pressure of the sucked air (bar), q is the flow rate of the sucked air (m3/h), and p2 is the absolute pressure of the air leav- ing the blower (bar). Formula (1) shows that the power required for compressed air production depends on the flow and pressure. In order to work at constant tonnage, the required flow must be produced at a constant rate, and the pressure must be kept at the lowest possible val- ue. In Figure 2, the pressure and power curve of a blow- er used in compressed air production is given [1]. As it can be seen in the figure, considering that the produced flow rate remains approximately constant, it is seen that the energy consumption moves in the same way as the pressure. This graph shows how effective the pressure used is on energy consumption. Today's energy saving methods in compressed air production always keep the pressure value constant at the usage value, and increase or decrease the flow according to the need. In this case, only the flow can be controlled and the pressure value cannot be interfered with. It could be seen from Figure 2, that a more successful result can be obtained than today's known energy-saving method if the production and consumption of the com- pressed air used for cleaning the jet filter bags are syn- chronized [1]. Thanks to an algorithm to be developed, it is possible to control together both flow rate and pres- sure, not only the flow rate. Artificial intelligence-based Jetmaster Deep series advanced process controllers reinforced with deep learning have such an algorithm. 3.3. Filter Timer The operating logic of the devices that control the JPF bag cleaning process, called the filter brain in the indus- try, remained as it was first developed by Bühler in 1979. Despite the intervening more than 40 years, jet filters are still controlled depending on time. Two parameters are used here. One determines waiting time (off time) and the other determines blow duration (on time). But, it is a completely outdated control method. Even if the Figure 2. Effect of Pressure on Energy Consumption Figure 3. Energy Consumption When Using Classi- cal Filter Timer