The working principle of the twin - screw conveyor pump is as follows:
1. **Basic structural composition and driving mode**:
- **Screw components**: The twin - screw conveyor pump has two meshing screws that do not touch each other. One is the driving screw, which is usually driven to rotate by a prime mover (such as an electric motor); the other is the driven screw, which is rotated by the driving screw through a synchronous gear. The driving screw and the driven screw have threads with different helix directions (if the former is right - handed, the latter is left - handed). This design ensures that the two screws cooperate with each other during rotation to achieve the transportation of liquid.
- **Pump body and clearances**: The screws fit closely with the pump body. There are certain clearances between the outer cylindrical surface of the screws and the pump body and between the screws. The size of these clearances has an important impact on the performance and conveying efficiency of the pump. Precise control is required during the design and manufacturing process to ensure that the screws can rotate normally and to minimize the leakage of liquid in the clearances as much as possible.
- **Synchronous gear**: The synchronous gear is a key component to ensure that the driving screw and the driven screw can rotate synchronously. It can accurately transmit power, making the two screws rotate in a certain proportion and direction to ensure that the liquid can be continuously and stably transported.
2. **Liquid suction process**: When the screws start to rotate, at the suction end of the pump, as the screws rotate, the volume of the sealed cavity formed between the screws and between the screws and the pump body gradually increases, creating a negative pressure. Under the action of the pressure difference inside and outside the pump, the liquid is sucked into the pump and fills the continuously expanding sealed cavity. At this time, the liquid enters the suction cavity from the suction pipe, just like an expanding container sucking in liquid.
3. **Liquid conveying process**: As the screws continue to rotate, the sealed cavity filled with liquid continuously moves forward along the axial direction of the screws, moving from the suction end to the discharge end. During this process, the volume of the sealed cavity remains unchanged, and the liquid is enclosed in it, moving within the pump like a "liquid capsule". Since the rotation of the screws is continuous, the liquid transportation is also continuous and uniform.
4. **Liquid discharge process**: When the sealed cavity moves to the discharge end of the pump, as the space at the discharge end gradually shrinks, the liquid in the sealed cavity is compressed and the pressure increases. When the pressure increases enough to overcome the resistance of the discharge pipe, the liquid is discharged out of the pump, completing a complete transportation process.
In short, the twin - screw conveyor pump uses the volume change of the sealed cavity formed by the two meshing screws during rotation to achieve the suction, transportation, and discharge of liquid. It is an efficient and stable positive - displacement pump. This working principle gives the twin - screw conveyor pump advantages such as stable transportation, strong self - priming ability, and a wide application range. It has been widely used in industries such as petroleum, chemical engineering, and food.
