Screw Vacuum Pump Variable Pitch Rotor Heat Dissipation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Screw vacuum pumps face challenges with high power consumption and overheating at high intake pressures due to limited compression ratios and inefficient heat dissipation, which increases manufacturing and maintenance costs, and reduces pumping speed.
Innovation Solution
The design features long screw rotors mounted on both sides with a variable pitch and multiple windings on the pressure side, where the pitch change is minimal, allowing for a compression ratio of at least 4.5 and effective heat dissipation through the pump housing, reducing power consumption and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the compression ratio is increased to reduce power consumption, then power consumption decreases, but heat dissipation becomes insufficient and rotor overheating occurs
Solution Approach 1:
The rotor is segmented into suction side and pressure side windings with different pitch characteristics. The suction side has larger pitch for efficient compression, while the pressure side has smaller pitch for extended heat dissipation area, allowing the rotor to simultaneously achieve high compression ratio and effective heat dissipation.
Solution Approach 2:
Different regions of the rotor are given different local properties: the suction side windings have larger pitch for compression efficiency, while the pressure side windings have smaller pitch for heat dissipation. This local differentiation allows the rotor to optimize both compression and thermal management functions in different areas.
2Temperature
If the rotor length is increased to extend compression area, then heat dissipation improves, but rotor complexity and manufacturing difficulty increase
Solution Approach 1:
The rotor employs variable pitch windings that dynamically adjust the pitch size along the rotor length. The pitch transitions from larger values at the suction side to smaller values at the pressure side, creating an optimized compression and heat dissipation profile without requiring excessive rotor length or complex internal structures.
Solution Approach 2:
The pitch parameter of the windings is changed along the rotor length to optimize performance. By varying the pitch from large at the suction side to small at the pressure side, the rotor achieves extended compression area and improved heat dissipation while maintaining a relatively simple overall structure that avoids excessive complexity.
3Temperature
If the rotor diameter is reduced to improve heat dissipation area, then heat dissipation efficiency increases, but compression ratio capability decreases
Solution Approach 1:
The design transitions from optimizing heat dissipation through rotor diameter to optimizing it through rotor length and pitch variation. By extending the rotor length and implementing variable pitch windings, the heat dissipation area is increased without reducing the rotor diameter, thereby maintaining high compression ratio capability while achieving effective heat dissipation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration achieves a higher compression ratio with reduced power consumption and noise, enabling efficient heat dissipation and maintaining pumping speed while avoiding overheating, with power consumption as low as 12 W/(m³·h) at low pressures and a noise reduction of 3-6 dB(A).
Implementation Method 1
the rotors have a built-in compression ratio, i. H. a ratio of the chamber volume of the suction-side chamber to the pressure-side chamber of less than 4
Implementation Method 2
Heat dissipation is no longer possible via the pump housing, so that heat dissipation would have to take place via internal cooling of the screw rotors
Implementation Method 3
the compression work and thus the waste heat essentially occurs in the area of high pressures
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a screw vacuum pump comprising screw rotors (12, 14) disposed in a suction chamber (10). The screw rotors (12, 14) are each supported by means of two bearing elements (20) in the pump housing and comprise a ratio of rotor length (I) to rotor axis spacing (d) that is greater than 3.0. The screw rotors (12, 14) further comprise a variable pitch, at least 7 turns, and an integral compression ratio of at least 4.5. The pitch after half of the turns is less than twice the pitch on the pressure side rotor outlet (24).