Introduction

The twin-screw pump has two types: sealed and unsealed. Depending on whether the medium enters the meshing space from one end or both ends, the twin-screw is further divided into double-suction and single-suction structures.

The twin-screw pump is an external meshing screw pump that uses two intermeshing, non-contacting screws to pump liquids.

The twin-screw pump is a double-suction, non-closed twin-screw pump. One end of the active screw extends outside the pump and is driven by a prime mover. The active screw and the driven screw have threads that rotate in different directions. The screw is closely fitted to the pump body. The driven screw is driven by the active screw through a set of synchronous gears.

As a positive displacement pump, the suction chamber inside the pump must be tightly separated from the discharge chamber. Therefore, the gap between the outer surface of the screw and the pump body, as well as the gap between the screws, should be as small as possible. At the same time, the screws and the pump body, as well as the screws with each other, form a sealing chamber to ensure closure; otherwise, liquid may flow back through the gaps.

Twin-screw pumps can be divided into two forms: internal bearing and external bearing. In the internal bearing structure, the bearing is lubricated by the conveyed medium. In the external bearing structure, the working chamber of the twin-screw pump is separate from the bearing. Due to the structure of this pump and the side gaps between the screws, it can transport non-lubricating media. In addition, adjusting the synchronous gears allows the screws to not contact each other while transmitting half of the output torque to the driven screw. Like all screw pumps, the external bearing twin-screw pump also has self-priming capability, and most pump conveying elements are symmetrically arranged in a double-suction manner, which can eliminate axial forces and has a large suction height.

The twin-screw pump series products are divided into single-suction twin-screw pumps and double-suction twin-screw pumps. This series of products has special screw profiles and matching special structures, widely applicable in various industries such as petroleum, chemical, metallurgy, steel, electric power, shipping, pharmaceuticals, food, and building materials. The wide range of applicable media, broad conveying range, and complex working conditions are unmatched by other pump products. These characteristics also give this series of pumps a potential for future development.

Structural Features

This type of pump adopts a double-suction structure, with both ends of the screw in the same pressure chamber, allowing axial forces to balance themselves. The bearings at both ends are externally mounted and lubricated separately with oil (grease), thus not affected by the conveyed medium. A pair of synchronous gears drive the two screws, which do not contact each other but leave a small gap, preventing impurities in the medium from directly wearing the screw tooth surfaces (except for scouring). Except for some small displacement pumps (below 2W.W4.0), the pump body generally has an internal flow safety valve, which provides some protection when the discharge pressure exceeds the rated value. There are two directions for the inlet and outlet on the pump body: one is horizontal inlet and horizontal outlet; the other is horizontal inlet and vertical outlet. Users can choose according to their needs.

Special Advantages

1. Smooth liquid delivery, no pulsation, no stirring, low vibration, and low noise.
2. Strong self-priming capability, with a gas content not exceeding 80% and a sand content not exceeding 500g/m3 during multiphase mixed transport.
3. External bearing structure with independent lubrication, capable of transporting various non-lubricating media.
4. Synchronous gear drive, with no contact between the two rotors, allowing for short periods of idling without issue.
5. The pump body is equipped with a heating jacket, capable of transporting various clean or solid particle-containing low or high viscosity media (generally with particle diameters less than 0.12-0.2mm).
6. Correct material selection allows for the transport of many corrosive media.
7. Double-suction structure, with no axial force on the rotor.
8. The shaft end uses mechanical seals or corrugated mechanical seals, characterized by long life, low leakage, and a wide range of applicability.