1. Raw Material Mixing System
The raw material mixing system is the core component for processing raw materials in a polyurethane filter element machine and it primarily consists of a raw material storage tank a metering pump a mixing chamber and a stirring device. Its core function is to ensure precise proportioning and uniform mixing of polyurethane raw materials (such as polyether polyols isocyanates and catalysts) and the raw material storage tanks store different types of liquid PU raw materials or prepolymers while the metering pump accurately delivers the raw materials to the mixing chamber based on preset process parameters (such as the raw material ratio) and the stirring device rotates at high speed to thoroughly blend the various raw materials forming a uniform polyurethane mixture. This paves the way for subsequent bonding with the filter element substrate preventing quality issues such as bubbles and poor adhesion caused by uneven raw material mixing.
2. Substrate Conveying and Positioning Mechanism
This mechanism primarily consists of conveyor rollers guide wheels a tension controller and a positioning sensor and it functions for filter element substrates such as filter paper and non-woven fabrics. The conveyor rollers rotate at a constant speed continuously transporting the substrate to the forming area and guide wheels ensure the substrate does not shift during transport while a tension controller adjusts the substrate tension in real time (to avoid wrinkles caused by excessive looseness or stretching deformation caused by excessive tightness) and positioning sensors precisely control the substrate's position ensuring precise alignment with the subsequently injected polyurethane mixture. This ensures that the filter element structure (e.g., substrate winding accuracy for cylindrical filter elements pleat spacing for pleated filter elements) meets specification requirements.
3. Molding Mold
The molding mold is a key component that determines the filter element's shape and structure and different mold cavity structures are designed depending on the filter element type (e.g., cylindrical pleated or special-shaped) with common molds including cylindrical molds and pleated molding molds. Its function is to provide a "molding space" for the polyurethane to bond with the substrate and after the substrate is delivered to the mold the raw material mixing system injects the polyurethane mixture into the mold cavity while the mold's pre-set cavity structure restricts the flow of the mixture. Simultaneously the subsequent curing process ensures that the polyurethane and substrate are tightly bonded and form a fixed shape (such as the tubular structure of a cylindrical filter element or the pleated structure of a pleated filter element) ensuring that the filter element dimensions (diameter length and wall thickness) meet production standards.
4. Curing Device
The curing device typically utilizes a heating tube hot air circulation system or infrared heating element and its core function is to accelerate the curing reaction of the polyurethane mixture ensuring a stable bond between the polyurethane and the substrate. Depending on the type of polyurethane raw material (e.g., soft hard or heat-resistant) the curing device can adjust the temperature (usually between 50-120°C) and curing time and for example when producing rigid polyurethane filter elements the heating temperature and curing time are increased to ensure sufficient cross-linking and a rigid structure while when producing soft filter elements the temperature and curing time are appropriately lowered to preserve the polyurethane's elasticity. Furthermore the temperature uniformity of the curing unit prevents localized over-curing (causing brittle cracking) or under-curing (resulting in weak bond strength) on the filter element.
5. Cutting Mechanism
The cutting mechanism consists of a high-precision cutting blade (such as a circular blade or hydraulic cutting blade) a positioning assembly and a length sensor and it is used to cut the continuous stream of cured filter elements into finished products of a preset length. The length sensor monitors the filter element's conveying length in real time and when the set length (such as 200mm or 500mm) is reached the positioning assembly secures the filter element in place allowing the cutting blade to quickly complete the cut. The blade's sharpness and cutting speed can be adjusted based on the filter element material (such as polyurethane hardness and substrate thickness) ensuring a smooth burr-free cut surface and preventing damage to the filter element edges due to improper cutting which could compromise filtration performance.
6. Control System
The control system based on a PLC (Programmable Logic Controller) is equipped with a touch screen parameter sensors (temperature pressure and flow sensors) and actuators (solenoid valves and motor drivers) and it serves as the "central nervous system" of the equipment. Its functions include presetting and storing production process parameters for different filter elements (such as raw material ratios curing temperature and cutting lengths) collecting real-time operating data from various components (such as mixing chamber pressure curing temperature and substrate tension) and automatically issuing alarms and making adjustments if parameters deviate from set values (e.g., adjusting metering pump flow through solenoid valves and conveying speed through motor drives). This ensures coordinated operation of various equipment components (e.g., timing coordination for raw material mixing substrate delivery mold filling curing and cutting) ensuring a continuous and stable production process while facilitating operator monitoring and debugging.
7. Raw Material Conveying Pipes and Cleaning Components
The raw material conveying pipe connects the raw material storage tank to the mixing chamber and is responsible for conveying liquid PU raw material and the inner wall of the pipe is typically treated with an anti-stick treatment (such as a Teflon coating) to prevent residual material buildup. Cleaning components (such as high-pressure cleaning pumps and solvent storage tanks) are used to clean pipelines after equipment shutdown: cleaning solvents (such as special PU cleaning agents) are injected into the pipelines through high-pressure cleaning pumps to flush out residual polyurethane raw materials preventing pipeline blockage or residual raw materials from solidifying and affecting the purity of the next batch of raw materials thereby ensuring long-term and stable operation of the equipment.