The timing of vacuum or blow depends on the bridge set of the main valve.The drum deck is divided into separately isolated compartments each subjected to vacuum or blow while the drum is in rotation.Since in continuous operation both lower and upper zones are under vacuum this bridge is slightly narrower than the internal pipe port so that the vacuum is continuous and the cake is held onto the drum.
Once the cake starts to emerge from the tank the valve is gradually opened and fully opened when the entire drum face is wrapped in the cake.Start-up assist bridge: At start-up, the upper vacuum zone is open to atmosphere and a cake may be formed only when closing the valve that controls this zone.Dead zone bridge: This bridge opens to vacuum once a compartment submerges.This bridge cuts off the vacuum so it is slightly wider than the internal pipe port The duty of the bridges is: Vacuum and blow zones separating bridge.The majority of drum filters have a valve with three bridge blocks and a single row pipe plate as shown below and on the right.Adjustable bridge blocks enable the optimization of form to dry ratio within the filtration cycle as well as the "effective submergence" of the drum when the slurry level in the tank is at the maximum.The valve has on certain filters adjustable blocks and on others a fixed bridge ring.When a sector enters submergence vacuum commences and continues through washing, if required, to a point that it is cut-off and blow takes place to assist in discharging the cake.A valve with a bridge setting controls the sequence of the cycle so that each sector is subjected to vacuum, blow and a dead zone.The internal piping that is connected to each sector passes through the trunion and ends up with a wear plate having ports that correspond to the number of sectors.The drum face is divided into circumferential sectors each forming a separate vacuum cell.The drum is supported by a large diameter trunion on the valve end and a bearing on the drive end.Customers can avail this drum filter from us at competitive rates. Also, our offered drum filter provides operating flexibility to handle dewatering, washing. This drum filter is manufactured using highly advanced techniques & quality material to fulfilling the requirements of our customers. We are prominent and trustworthy manufacturer and supplier of the top quality range of Rotary Vacuum Drum Filter.