Parallel Roots Vacuum Pump Gear Drive for Efficiency
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Solution Overview
Problem
Current Roots vacuum pumps with a two-shaft design have low pumping efficiency due to low compression ratio, while three-shaft designs with serially connected chambers suffer from increased complexity, heat expansion issues, and reduced steadiness.
Innovation Solution
A parallel connected multiple shaft Roots vacuum pump design, where an electric motor drives an active bladed rotor, and power is transferred through an N-1 bridge gear set to synchronously rotate driven blade rotors, improving efficiency and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If serially connected chambers are used to increase pumping speed and vacuum ratio, then pumping efficiency is improved, but device complexity increases and installation becomes complicated
Solution Approach 1:
The patent merges multiple pump chambers into a single integrated structure with a common crankcase. Multiple rotors (at least three rotors with different numbers of lobes) operate simultaneously within one chamber, eliminating the need for separate serially connected chambers. This integration maintains high pumping speed while reducing device complexity and installation complexity.
Solution Approach 2:
The patent segments the pumping function across multiple rotors with different lobe configurations within a single chamber. Each rotor handles different aspects of the pumping process, allowing the system to achieve the performance of multiple serial chambers while operating in parallel within one integrated space.
2Volume of moving object
If long shafts are used in serially connected chambers, then pumping coverage is increased, but heat expansion increases and accumulation errors occur
Solution Approach 1:
The patent divides the pumping function across multiple shorter rotors instead of using one long shaft. Each rotor has its own drive mechanism, allowing the system to achieve extended pumping coverage through parallel operation of multiple compact units rather than extending a single long shaft, thereby reducing heat expansion and accumulation errors.
3Productivity
If multiple serially connected chambers are used, then pumping ability is improved, but engagement of rotors internally deteriorates and collisions occur
Solution Approach 1:
The patent merges multiple rotor systems into a single coordinated chamber where rotors with different lobe configurations work together. The rotors are designed with complementary profiles that ensure proper engagement and clearance, preventing collisions while maintaining high pumping ability through parallel operation.
4Device complexity
If two-shaft design is used, then structure is simplified, but pumping efficiency decreases due to low compression ratio
Solution Approach 1:
The patent segments the pumping action across multiple rotors with different numbers of lobes (e.g., a three-lobed rotor and a two-lobed rotor) that operate in parallel within the same chamber. This segmentation allows different stages of compression to occur simultaneously, maintaining structural simplicity while achieving high pumping efficiency through multi-stage parallel compression.
Solution Approach 2:
The patent changes the parameters of the rotors by using different numbers of lobes on different rotors within the same system. This parameter variation enables different compression ratios to be achieved simultaneously by different rotors, optimizing pumping efficiency across the entire pressure range while maintaining a simple two-shaft drive structure.
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
The design achieves high pumping ability, low power consumption, and improved steadiness with reduced heat expansion and complexity, while maintaining a compact structure and ease of maintenance.
Implementation Method 1
an electric motor (30)
Implementation Method 2
a bridge gear set (9) is installed between the active driving gear (8) and two driven gears (402, 403)
Data Source
AI summary
A parallel connected multiple shaft roots vacuum pump includes an electric motor (30); a pump body which has N (N is an integers and is greater or equal to 2) parallel pump chambers (11); a bladed rotor set (4) installed within the pump body and including an active bladed rotor (3), and 2N-1 driven bladed rotors (41, 42, 43); wherein the active bladed rotor includes an active driving gear (8); each driven bladed rotor includes a respective driven gear (401, 402, 403) which are installed at two sides of the active driving gear; a bridge gear set (9) is installed between the active driving gear (8) and two driven gears (402, 403) at a right side of the active driving gear.