Suction boxes

Fig. 4. Fourdrinier paper machine A, headbox B, Fourdrinier wet end with foil boxes C, wet and D, dry suction boxes, pickup, and closed transfer of web...

A belt filter consists of an endless reinforced rubber belt, with drainage hole along its centre, which supports the filter medium. The belt passes over a stationary suction box, into which the filtrate is sucked. Slurry and wash water are sprayed on to the top of the belt. 

The filter unit was located entirely inside the respective buildings and was independent of the ventilation system. The unit consisted of a suction box (usually floor standing) to which the filter material was attached usually as a flat vertical surface of an area to give a face velocity of about 0.75 m/s. Dust collected on this surface and was removed with a vacuum cleaner. Cleaned air was directed into an overhead discharge duct with a permeable lower surface. The capacity of the fan in the filter unit was made the same order as that of the main ventilating fan. The overhead duct was located above and as near to the stock as possible so that the clean air flowed downwards towards the stock. This air did not cause a draught because it was discharged at a low speed (0.3 m/s) and as it was recirculated it was at the same temperature as the air in the room. 

Paper is placed in a hydropulper, a large water tank equipped with a heavy motor-driven propeller at the bottom. The propeller agitates the water and wet paper and separates the paper fibers into a fiber slurry. Additives are added and mixed as needed at this point. This is a batch process and as such requires more than one hydropulper in order to be processing one tank as another is being emptied of slurry and refilled with water. The slurry is pumped into a box having a large-diameter cylinder covered by a wire screen rotating slowly within it. Fibers are deposited on the screen as water is pumped out of the screen and returned to the process. The fiber mat is carried up and over as the screen rotates and then transferred to a flat wire screen belt which moves the mat across suction boxes and onto the dryers. 

Pulp is continuously fed into the fourdrinier machine on the surface of a moving endless belt of fine mesh screening, usually made of nylon. Deckle straps prevent the liquid pulp from slopping over the sides. The screening is shaken from side to side as it moves forward to help drain the water. Suction boxes below the screening pull more water through, as a wire-mesh-covered cylinder presses on the web of pulp from above. The cylinder may be covered with a plain wire cloth to impart a wove effect, or with wire in a ladder pattern to produce a laid effect. To produce a watermark, the paper-maker attaches a wire design to the cylinder. 

Use Plating barrels, rayon-manufacturing equipment, pickling tanks, electrical and thermal insulation, oil-handling equipment, steel rolling-mill bearings, chemical-handling valve bodies, paper-mill suction box covers and equipment. 

Foils, table rolls and suction boxes aid the natural drainage through the wire... 

Chain guides, star wheels, feed screws Truckbeds, hopper bunker liners Suction box covers, rollers, foil blades Knee, shoulder and hip implants Food preparation surfaces Lead acid battery separators Ballistic cloth, fishing lines and nets Snow ski soles, snowmobile boogie wheels... 

The horizontal belt is a continuous filter with an endless cloth supported on a perforated belt (see Figure 1.23). The belt and cloth are driven around two rollers and across a sequence of evacuated suction boxes at linear speeds up to 0.5 m s The feed suspension is introduced at one end of the filter and deliquored to produce a cake. The length of the filter, which can be in excess of 60 m, is arranged to allow adequate cake formation as well as the... 

A) Tanks shall be provided with weirs, skimmer plates, or screens to prevent sludge and floating paint from entering the pump suction box. Means for automatically maintaining the proper water level shall also be provided. Fresh water inlets shall not be submerged. They shall terminate at least one pipe diameter above the safety overflow level of the tank. 

The surface of the used conveyor belt is linked to the surface of the produced web. For certain filter applications, it is necessary to have a smooth surface created by fine mesh belts. A suction box in order to transport the air through the belt is integrated into the conveyor belt machine. Since the attenuation air can hit the belt with high speed, also the suction air needs to handle these high speeds. 

---