VSD Vacuum Pump Speed Control for Cyclic Pumpdown
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pumping systems, particularly those using Variable Speed Drive (VSD) vacuum pumps in cyclic applications, face inefficiencies due to energy waste and performance loss during transitions between cycles, as they require time to accelerate from low to maximum speed, increasing pumpdown time and reducing throughput.
Innovation Solution
A speed controlling method for VSD vacuum pumps that analyzes cycle durations and acceleration times to accelerate the pump during the holding phase of one cycle, ensuring full capacity is reached at the start of the next cycle, thereby eliminating acceleration delays and optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the pump is slowed down during the holding phase to save energy, then energy consumption is reduced, but the acceleration time to maximum speed increases
Solution Approach 1:
The pump is accelerated during the holding phase of the current cycle before the next pumpdown phase begins. This preliminary acceleration ensures that the pump reaches maximum speed ready for the next pumpdown, eliminating the need for acceleration delay at the start of each cycle and resolving the contradiction between energy savings and acceleration time
2Loss of time
If the pump operates at maximum speed during the holding phase to maintain ready state, then acceleration delay is eliminated, but energy consumption increases
Solution Approach 1:
Instead of maintaining maximum speed throughout the holding phase, the pump performs preliminary acceleration during this phase. The acceleration is timed to complete before the next pumpdown phase starts, eliminating acceleration delay while avoiding continuous high-speed operation and excessive energy consumption
Solution Approach 2:
The pump speed is dynamically adjusted during the holding phase based on the timing requirements of the next pumpdown phase. The speed profile is optimized to reach maximum speed at the optimal moment, balancing energy consumption with the need to eliminate acceleration delay
3Use of energy by moving object
If the pump accelerates from lowest speed at the start of each pumpdown phase, then energy efficiency is maintained, but pumpdown time increases
Solution Approach 1:
The pump performs preliminary acceleration during the holding phase of the current cycle, so that by the time the next pumpdown phase begins, the pump is already at or near maximum speed. This eliminates the acceleration delay at the start of each pumpdown phase, maintaining energy efficiency while significantly improving pumpdown throughput and productivity
Data Source
AI summary
Repeated cycles each consist of a pump down phase and a holding phase, wherein a start timepoint of each cycle is the timepoint when a rise in an inlet pressure of the pump is sufficiently large and the time extending between two consecutive cycle start timepoints is a cycle time. A control method includes determining a start of a next cycle during a present cycle, wherein it is preferable that the present cycle directly precedes the next cycle. The method further includes controlling the pump to accelerate to a maximum allowed speed during the holding phase of the present cycle before the start of the next cycle such that at the start of the next cycle full pump capacity is available.