Working Principle
The working principle of the gear pump in the coating machine is based on the rotation and meshing of gears. When the gear pump starts to operate, the fluid between the teeth of the two synchronously rotating gears is squeezed into the gear tooth grooves and rotates together with the gears. This generates a certain pressure, enabling the medium to be sucked in from the inlet and then transported to the outlet through the pump body.
This type of pump is usually divided into two types: internal gear pumps and external gear pumps. Their specific structures and working methods are slightly different, but the basic principles are similar. An internal gear pump consists of an internal gear and an external gear. The external gear drives the internal gear to rotate, forming a sealed space at the gear meshing point to achieve fluid transportation. An external gear pump has two external gears meshing with each other. As the gears rotate, the volume of the working chamber inside the pump body changes, thereby realizing the suction and discharge of the fluid.
Features
High output pressure: It can generate a relatively high output pressure to meet the pressure requirements during the coating process. It can transport high - viscosity media such as glue or paint to the coating head or coating roller, ensuring uniform coating.
High - viscosity medium transportation: It is suitable for transporting high - viscosity media with a viscosity range of 1cp to 5 million cp, such as hot - melt adhesives and high - viscosity glues. It can stably transport in a high - viscosity state, ensuring the normal progress of the coating process.
High operating temperature: The pump body material usually has high heat resistance and can adapt to the transportation of high - temperature media. It can be used in the coating process of glues or paints that need to be heated, with an operating temperature of up to 200°C or even higher.
Wide flow range: It can achieve a wide range of flow regulation. By changing the motor speed or gear size, etc., the transportation volume of glue or paint can be precisely controlled to meet the requirements of different coating speeds and coating thicknesses.
Corrosion - resistant and wear - resistant: The pump body is generally made of materials with good corrosion - resistance and wear - resistance, such as stainless steel and alloy steel. It can resist the corrosion of media such as glue and paint, and at the same time reduce the wear of components such as gears, extending the service life of the pump.
Small pressure and flow pulsation: It operates smoothly with small pressure and flow pulsations. It can achieve nearly linear flow output, which is easy to control, making the coating process more stable and contributing to improving the coating quality.
High precision: It has a precise structure and high precision. The flow repeatability accuracy is < ±1%, enabling high - precision fluid transportation within a wide flow range and ensuring the uniformity and consistency of the coating thickness.
Good self - priming ability: It can be applied to working conditions with an inlet vacuum of (-0.1mpa). Even when the storage container of glue or paint is in a relatively low position, it can smoothly suck in and transport the medium.
Application Fields
Packaging industry: It is used for the bonding of materials such as cartons, labels, and plastic films. Hot - melt adhesives or glues are evenly coated on packaging materials to ensure the firmness and tightness of the packaging.
Printing industry: During the printing process, glues or paints are evenly coated on printing materials for processes such as paper pasting and binding, improving the quality and aesthetics of printed products.
Textile industry: It is used for the coating treatment of textiles, such as the coating of waterproof, antifouling, and flame - retardant coatings, improving the performance and added value of textiles.
Electronics industry: It is used for the encapsulation, fixation, and bonding of circuit boards, electronic components, etc. Glues or paints are precisely coated on electronic components to ensure the stability and reliability of electronic products.
Automotive industry: It is used for the application of sealants on parts such as the car body, windows, and seats, improving the comfort and safety of the vehicle and preventing rainwater, dust, etc. from entering the vehicle.
Selection Key Points
Medium characteristics: Consider the characteristics of the glue or paint, such as viscosity, corrosiveness, and temperature. For high - viscosity media, a gear pump suitable for high - viscosity transportation should be selected; for corrosive media, a gear pump with a corrosion - resistant pump body material should be chosen; for high - temperature media, a gear pump with good high - temperature resistance should be selected.
Flow and pressure requirements: Determine the flow and pressure range of the gear pump according to the production speed of the coating machine and the coating process requirements. Ensure that the selected gear pump can work stably at the required flow and pressure to meet the transportation needs of glue or paint.
Accuracy requirements: For processes with high coating accuracy requirements, a gear pump with high metering accuracy should be selected, such as products with high flow repeatability accuracy, to ensure the uniformity and consistency of glue or paint coating.
Working environment: Consider the working environment of the gear pump, such as whether functions like explosion - proof, dust - proof, and waterproof are required. If there are flammable and explosive gases in the working environment, an explosion - proof gear pump should be selected; if working in a dusty environment, a gear pump with dust - proof sealing should be chosen.
Drive mode: The main drive modes of gear pumps include motor drive and hydraulic drive. Motor drive has the advantages of simple structure, low cost, and convenient maintenance; hydraulic drive has the advantages of high output torque and wide speed - regulation range. The appropriate drive mode should be selected according to actual needs.
