Roots Vacuum Pump Outlet Layout for Powder Buildup Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pumping units used in processes that generate solid by-products, such as those in semiconductor manufacturing, face issues with powder accumulation that reduces pumping capacity and requires frequent, time-consuming maintenance due to the difficulty in cleaning the inter-pump pipeline.
Innovation Solution
A pumping unit design with a Roots vacuum pump and a rough-vacuum pump in series, where the Roots vacuum pump's outlet orifice is positioned close to its rotors to mechanically sweep away accumulated powders, and a straight pipeline with a detachable downstream portion for easier maintenance, along with a cooling circuit to prevent powder agglomeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pipeline connecting the two vacuum pumps is removed frequently for cleaning, then powder accumulation is reduced, but maintenance time and complexity increase
Solution Approach 1:
The rotors perform self-cleaning by mechanically scraping powders from the outlet orifice edges during their rotation. The pumping unit automatically removes accumulated powders without requiring external intervention or pipeline removal, converting the system into a self-maintaining configuration that prevents clogging while minimizing maintenance time
Solution Approach 2:
The outlet orifice is positioned close to the rotors before powder accumulation becomes problematic. This preliminary geometric arrangement ensures that powders are scraped off at the earliest stage of accumulation, preventing clogging before it occurs and eliminating the need for frequent maintenance interruptions
2Reliability
If the outlet orifice is positioned closer to the rotors, then powder scraping efficiency increases, but the risk of rotor-orifice collision increases
Solution Approach 1:
The outlet orifice is positioned at a specific optimized distance from the rotors, creating a localized cleaning zone where powders can be effectively scraped without risking rotor collision. This precise geometric arrangement ensures that only the necessary area is cleaned while maintaining safe operational clearance
Solution Approach 2:
The rotors sweep through a path that partially overlaps with the outlet orifice area, providing sufficient cleaning action to remove powders effectively. The overlap is controlled to be just enough for cleaning purposes without extending to the point of causing collision, achieving optimal cleaning with minimal risk
3Ease of manufacture
If the pipeline has bent portions, then installation flexibility improves, but powder deposition increases
Solution Approach 1:
The pipeline is divided into segments, with the section closest to the Roots pump outlet kept straight to prevent powder deposition. This segmentation allows the pipeline to maintain installation flexibility through bends in downstream sections while ensuring the critical near-pump region remains free of accumulation zones
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 design reduces powder accumulation, maintains gas passage, and facilitates quicker maintenance by allowing the cleaning of the pipeline without removing the pumps, thereby extending the operational life and efficiency of the pumping unit.
Implementation Method 1
the rotors can sweep powders that have accumulated on the edges of the outlet orifice. Any accumulation of powder protruding from the outlet orifice can thus be scraped automatically by way of a mechanical effect and entrained with the pumped gases out of the pumping stage
Implementation Method 2
a cooling circuit to prevent polymerization
Data Source
AI summary
A pumping system is provided, including a rough-vacuum pump; a Roots vacuum pump including a pumping stage having a stator inside which two Roots rotors are configured to rotate synchronously in opposite directions to drive a gas to be pumped between an inlet orifice and an outlet orifice; and a pipeline connecting the outlet orifice to an intake of the rough-vacuum pump, a shortest distance between an edge of the outlet orifice and each of the Roots rotors in the pumping stage being less than 3 cm, and the outlet orifice being situated at the end of an upstream tube of the pipeline that passes into the pumping stage.