SEPCO SAS Saves Tissue Plant from Pulper Trouble

SEPCO Goal: Achieve water savings and maintenance cost savings, including labor, packing material costs, opportunity cost losses, and reducing the hazards of a flooded area due to packing failures on three tissue pulpers. These three pulpers at a tissue manufacturer in Mississippi had reliability issues with packing due to excessive shaft runout, concentricity issues with the shaft, and premature packing failures leading to all the previously mentioned losses.

Defining a Pulper: A pulper is a machine used in the tissue paper manufacturing process to break down raw materials into pulp. The pulp is then processed to achieve the desired quality and consistency before being fed into the tissue paper machines.

Understanding Pulpers in Tissue Paper Plants:

• Pulping Process: Pulpers can remove contaminants, slush, and disperse adhesives, fillers, and other materials.
• Pulping Chemicals: Pulpers can contain hot water and pulping chemicals.
• Machine Size: The size of a pulper can vary depending on the plant’s capacity and requirements.
• Types of Pulpers: Different types of pulpers include the hydra pulper, commonly used for waste pulp production, and the broke pulper, which can work with virgin pulp, recycled paper, and more.
• Stock Preparation: The process of breaking down raw materials into pulp is called stock preparation.
• Paper Machine: The pulp is fed into a headbox, which distributes it onto a wire frame or crescent former machine. The pulp then dries and forms into sheets that are rolled onto a reel.

SEPCO collaborated with a distributor to address these concerns by recommending an SAS (SEPCO Air Seal). SEPCO suggested adding a bushing combination with a lantern ring groove manufactured by our P3 plastics division in Texas. The water used as a lubricant on the bushings is minimal compared to the packing. The bushings were recommended to reduce the volume of air needed by the SAS by restricting the flow of air into the stuffing box, as the shaft was a bottom entry. The bushings were also recommended due to the excessive runout. The SAS can accommodate up to ¼” runout, but given the additional concentricity issues that could not be easily addressed—as the shaft had a boss in the stuffing box design—the plant contractors would be unable to resolve this; therefore, the bushings would take the damage before the SAS throttle would. SEPCO used cross-section gauges to find the most accurate concentricity measurements and bore ID to manufacture the bushings.

SEPCO’s distributor provided and installed a new shaft sleeve for the SAS to prevent it from being set on a corroded shaft that had a step. They also cut new swing bolts to the correct length to position the SAS properly. SEPCO installed the SAS and ensured that the air pressure was correctly connected to the seal with a regulator and that water flow to the bushings was reduced with a valve and pressure gauge on the discharge side.

The end-user has been very pleased with the success of SEPCO’s Air Seal (SAS), which is running very efficiently with zero leakage and no need for maintenance. Over $1,000,000 is expected to be saved by the plant over the next year with the three pulpers combined after choosing SEPCO as their fluid sealing manufacturer.