Screw pumps are divided into single screw pumps, twin screw pumps, triple screw pumps, etc. This article expounds the differences between their structure, characteristics, performance parameters, and application occasions, as well as their respective advantages and disadvantages. For example, the structure of the single-screw pump is that the single-head male screw rotor rotates eccentrically in a special double-head female screw stator (the stator is soft), which can swing back and forth along the center line of the pump, and is always meshed with the stator. The structure of the twin-screw pump In order to have two screw shafts of the same size, one is the driving shaft, the other is the driven shaft, and the synchronous rotation is achieved through gear transmission, and so on.
Single screw pump
structure:
The single-ended male helical rotor rotates eccentrically in a special double-ended female helical stator (the stator is soft) and can swing back and forth along the pump centerline
move and keep in mesh with the stator
Features:
1. It can transport liquids containing solid particles
2. It can be used for almost any viscosity fluid, especially for highly viscous and non-Newtonian fluids
3. The working temperature is limited by the stator material
Performance parameters:
Flow up to 150m³/h, pressure up to 20MPa
Application: For molasses, pulp, starch paste, chocolate syrup, paint, asphalt, paraffin, grease, mud, clay, terracotta, etc.
Twin-screw pump:
structure:
There are two screw shafts of the same size, one is the driving shaft and the other is the driven shaft, and the synchronous rotation is achieved through gear transmission.
Features:
1. A gap of 0.05~0.15mm is maintained between the screw and the pump body, as well as the screw, with small wear and long life.
2. The stuffing box is only affected by the suction pressure, and the leakage is small
3. Compared with the three-screw pump, it is not sensitive to impurities
Performance parameters:
The pressure is generally about 1.4 MPa, the maximum for viscous liquid is 7 MPa, and the liquid with low viscosity can reach 3 MPa.
Generally 6~600m³/h, maximum 1600m³/h
Liquid viscosity should not be greater than 1500mm²/s
Application:
For lubricating oil, grease, crude oil, asphalt, fuel oil, and other high viscosity oils
Three screw pump
Structure: It consists of a driving screw and two driven screws that mesh with it
Features:
1. The driving screw directly drives the driven screw, no gear transmission is required, and the structure is simple
2. The pump body itself is used as the bearing of the screw, and there is no need to install the radial bearing
3. The screw does not bear bending load and can be made very long, so high pressure can be obtained
4. It is not suitable to transport liquids containing solid impurities above 600μm
5. It can run at high speed, it is a small high-flow pump with high volumetric efficiency
6. The stuffing box is only connected to the suction pressure, and the leakage is small
Performance parameters:
The pressure can reach 70 MPa and the flow can reach 2000m³/h. Suitable for media with viscosity of 5~250 mm²/s.
