The preparation of cylindrical filter paper requires the selection of appropriate methods based on the application scenario. For small-scale laboratory preparation, filter paper cylinders or manual molding can be used, while for large-scale industrial production, specialized equipment and process control are required. The following are preparation methods in different scenarios:
Laboratory small-scale preparation method
Preparation of tools and materials
Filter paper cylinder: Choose specialized equipment with smooth edges and no burrs to ensure a smooth and snug fit of the filter paper.
Filter paper: Choose filter paper with moderate pore size and good toughness (such as food grade filter paper) according to experimental requirements to avoid the precipitation of harmful substances.
Scissors/cutters: Use precision cutting knives to ensure uniform diameter of the filter paper cylinder.
Label paper: used to identify sample information, it is recommended to use waterproof material.
operating steps
Measurement and Marking: Use a vernier caliper to measure the inner diameter of the filter paper and make corresponding marks on the filter paper.
Cutting: Place the marked filter paper on the cutting platform, maintain a stable angle, and quickly complete the cutting action.
Molding: Gently place the cut filter paper cylinder into the filter paper cylinder, check the fit, and ensure that there are no wrinkles or curled edges.
Identification: Use label paper to label the sample number, date, and other information, and stick it in a prominent position on the outside of the filter paper cylinder.
parameter control
Diameter error: The diameter error of the filter paper cylinder should be controlled within ± 0.2mm.
Cutting speed: It is recommended to maintain at 15-20 sheets per minute (adjusted according to equipment performance).
Identification information: It needs to be written with a marker pen to ensure clarity and recognizability even after high-temperature sterilization.
quality inspection
Randomly inspect 5-10 filter cartridges after each production, including consistency in diameter, adhesion between filter paper and cartridge wall, and completeness of identification information.
Abnormal samples need to be remade and the reasons for deviations analyzed.
Industrial large-scale preparation method
Material selection
Plant fiber filter paper: mainly made of wood pulp, with low cost and strong universality, suitable for most conventional filtration needs.
Synthetic fiber filter paper: made of materials such as polyester and polypropylene, it has the characteristics of acid and alkali resistance, high temperature resistance, etc., suitable for filtering operations in corrosive liquids or high temperature environments.
Composite filter paper: Combining the advantages of multiple materials, such as the inner layer being a high-strength support layer and the outer layer being a high-density filtration layer, to achieve a multifunctional integrated filtration effect.
forming process
Roll type filter paper: suitable for continuous paper filtration systems, easy to replace automatically, and suitable for large-scale continuous production.
Needle punching forming process: For non-woven filter materials used in filter bags, a sandwich structure is adopted (the middle layer is sparse woven fabric, and the upper and lower layers are fluffy non-woven felt), and the fiber web is combined with the woven fabric through needle punching to form a composite.
Cylindrical needle punching process: Utilizing the seamless characteristics of circular weft knitting, lining warp and weft knitted fabric is used, combined with a self-developed cylindrical needle punching machine to composite non-woven felt and knitted fabric into a cylindrical filter bag, reducing the sewing process and improving sealing.
Equipment and parameter control
Equipment: Use specialized cylindrical forming machines, needle punching machines, and other equipment to ensure the dimensional accuracy and structural stability of the filter cartridge.
Parameters: Based on the material and purpose of the filter paper, control parameters such as needle density, needle depth, and fiber web thickness to ensure filtration performance and service life.
quality inspection
Filtering accuracy: Select filter paper with different pore sizes according to process requirements to achieve full coverage from coarse filtration to ultrafine filtration.
Strength testing: testing the tensile strength, compressive strength, etc. of the filter cartridge to ensure that it is not easily damaged or leaked under high pressure and high-speed operating conditions.
Life test: Simulate actual working conditions to test the service life and filtration efficiency degradation of the filter cartridge.