Providing NASH vacuum pumps and related equipment to make paper at lower cost and higher quality is a NASH specialty. Our reputation as an industry leader in engineered vacuum systems and water removal for paper machines is well known.
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Headbox Compressor/Vacuum Pump
Used in "airpadded" headboxes, headbox compressor/ vacuum pumps create a pressure/vacuum above the stock level (or "pond" level) in the headbox to ultimately control the velocity by which the stock exits the headbox ("jet" velocity) onto the moving wire. NASH liquid ring pumps are usually configured to operate as both vacuum pumps and compressors through a series of valves. They either create a vacuum or a pressure in the void volume above the pond level to control the static head in the headbox.
Paper Machine Forming Section (Dewatering)
Nash vacuum pumps are used throughout the forming section of a paper machine to remove water from the paper stock. In the forming section, varying levels of vacuum are applied applied across the flat boxes and couch rolls to remove the bulk of the water.
Paper Machine Press Section Vacuum
Suction Pickup & Transfer Rolls
The suction pickup and transfer rolls use vacuum to transfer the paper from the forming section to the press section and guide the sheet from one felt to another in the press section.
The suction press uses mechanical action to extract the water from the paper sheet. In the press section, large granite or hard rubber covered rolls are placed in close contact to form a "nip". As the paper passes through the nips, the water is pressed out of the sheet into press felts that transport and cushion the sheet on its journey through the press section. Presses can have suction or non-suction rolls to aid in the water removal process.
Once the a pressing action occurs, the press fabric (or "felt") contains a mixture of: water and chemicals; paper stock; other contaminents. Since each felt is a continuous loop, the water and contaminants must be removed prior to the next pressing action. Uhle boxes are stationary suction boxes that span the width of the felt and extract the water and contaminants accumulated by the felt in the pressing process. Each felt can have up to two uhle boxes per felt. Preseparation is required on all uhle box applications to prevent process water carryover into the vacuum pump.
Vacuum Filtration (Pulp & Paper Stock)
Used on Brown Stock Washers, Lime & Mud Precoat Filters, Dregs Filters, and Deckers, the NASH pump pulls a vacuum on the interior of a rotating drum filter, removing proportionate amounts of liquid from the pulp, paper stock or other filtrate.