Miller Magazine Issue: 147 March 2022

88 COVER STORY MILLER / march 2022 Aspirator fans can be used before or after the jet filter. In Figure 1, the fan was used before the filter and pressurized the filter. In systems where the fan blows air into the filter, dust particles in the air col- lide with the fan blades, corrode these blades, and cause balance problems by sticking dust to the bla- des due to temperature and humidity. The bearings of the fans that work in balance cause breakdowns by disintegrating in a short time. In addition, due to the high air velocity at the fan outlet, dust partic- les hit the bags much faster, causing the bags to wear faster and explode. Due to the increased filter media pressure, the air density increases, the dust particles become easier to hang in the air, and the separation of dust and air becomes difficult with the cyclone effect. All the load remains in the filter bags. In addition, since there is a positive pressure in the filter, dust will come out from the smallest holes in the filter, which will negatively affect the cleaning. If the fan is used after the filter since the dust will be kept in the filter, it will not reach the fan and a smoother fan operation will be achieved. In addition, since suction, that is, the vacuum will occur in the filter, and the air density will decrease in the jet filter environ- ment, it will be difficult for the dust to remain in the air. Thus, the separation of dust and air due to gravity will occur in the filter cone to a large extent and less dust load will fall on the filter bags. Moreover, if a hole occurs in the fil- ters, dusty air will not come out from here, on the contrary, fresh air will be sucked in. Thus, the environment will not be dusty. However, if the fan is placed after the filter, the energy requirement will increase by around 2%. To- day's modern production approach is not for the fan to pressurize the filters, but for the suction from the filters.