Valves in action -
Bleeding and venting valve EB 1.84
Waste water treatment in a pulp mill
Water is essential in many industrial production areas and used as cooling agent or process medium. The paper and pulp industry employs water amongst others as solvent. It is mixed with various chemicals in order to dissolve the cellulose out of the wood. Here sulphides are particularly critical because they are present in nearly every process step. In addition, cellulose contains up to 3 % of solid matter so that at the end of the process the water is heavily particle-laden and contaminated with chemicals.
The rules and regulations of the water protection legislation prohibit the direct discharge of the contaminated water into the sewage system. Thus an effective water management re-feeds the water into the process water circuit or conducts it to the sewage network only after treatment and cleaning.
Task // Vacuum protection and air release
Unlike in cooling water systems where the return flow is constantly under a certain pressure, the sewage systems are often required to work with relatively low pressures and non-constant volume flows. This is why combined startup and continuous bleeding valves should be used instead of mere continuous bleeding valves. On the one hand, they protect the system against a vacuum in the event of low volume flows, on the other hand they quickly discharge potentially arising air quantities from the pipelines during continuous operation. As the particle-laden water is filtered prior to its treatment, the combined startup and continuous bleeding valves are installed at high points of the sewage line or directly onto the filter unit.
Solution // Combined valve for dirty and waster water
The float-controlled combined bleeding and venting valve EB 1.84 is the ideal solution for highly polluted water. It operates in accordance with the specific requirements, immediately opens in the event of a vacuum and removes large air quantities at startup. The deep-drawn body made of CrNiMo steel (316L) is particularly corrosion-resistant to the highly aggressive fluid. The entire float mechanism is located in the enlarged body. By this means, the float necessary for the control of the valve seats comes into contact with the dirty fluid but the whole cone and seat geometry is not wetted by the sewage and cannot get clogged by solid matter.
This valve ensures safe operation of the plant and contributes to protecting the environment and complying with legal requirements.
