Continuous Pump Control for Wastewater Energy Reduction
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Solution Overview
Problem
Traditional sewage pump stations face high energy and maintenance costs due to frequent pump starts and stops, and variable speed pumps are not more efficient in waste water applications, leading to increased energy consumption and greenhouse gas emissions.
Innovation Solution
A control system that manages three or more submerged pumps with a primary pump running continuously, supported by a secondary pump and a standby/emergency pump, utilizing a timer to rotate their roles monthly, reducing wear and tear and optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pump stations use multiple pumps with float switch control, then pump redundancy and reliability are improved, but energy consumption and maintenance costs increase due to frequent starts and stops
Solution Approach 1:
The patent applies continuous operation of a single pump instead of intermittent operation of multiple pumps. The pump runs continuously at minimum horsepower, eliminating frequent start-stop cycles that waste energy. This resolves the contradiction by maintaining reliability through continuous operation while reducing energy consumption by avoiding repeated motor startups.
Solution Approach 2:
The patent pre-positions a single pump to run continuously before peak flow conditions occur. By having the pump already running and ready, the system avoids the energy waste of starting multiple pumps during peak flows. The continuous operation prepares the system in advance, eliminating the need for reactive pump activation.
2Use of energy by moving object
If variable speed pumps are used, then energy efficiency is improved in some applications, but maintenance costs and initial purchase cost increase significantly
Solution Approach 1:
The patent uses simple, inexpensive constant speed pumps instead of expensive variable speed pumps. While constant speed pumps may have shorter operational life due to continuous running, the low initial cost and minimal maintenance requirements make them more cost-effective overall. This resolves the contradiction by choosing affordable, simple equipment that delivers sufficient energy efficiency without the high costs of variable speed technology.
Solution Approach 2:
The system uses a single continuous-running pump that requires minimal external control or monitoring. The pump serves itself by continuously handling waste water without needing complex variable speed control systems, sensors, or automated adjustments. This simplicity reduces both initial purchase costs and ongoing maintenance expenses while maintaining adequate energy efficiency.
3Productivity
If pumps are sized for peak flow conditions, then adequate pumping capacity is ensured, but energy consumption increases due to oversized pump operation
Solution Approach 1:
The patent uses a single pump operating at minimum horsepower continuously, providing partial pumping capacity during low-flow conditions and relying on the continuous operation rather than full capacity during all times. This partial action approach avoids the energy waste of running oversized pumps at low capacity while ensuring adequate total pumping capability is achieved through continuous rather than intermittent operation.
Data Source
AI summary
An electrical control system for energy efficient pump stations providing for continuous operation of a single primary pump with a second pump functioning as the support pump and a third pump acting as the standby/emergency pump. All pumps are of equal horsepower and horsepower selection is determined by the system curve to select the lowest, most efficient horsepower necessary to discharge water at the highest inflow rate while not allowing the water level to drop below the submerged pump level during continuous running of the primary pump. A timer having an indicator arm rotates one full revolution every thirty days changing the pump sequence to reduce wear and tear on individual pumps. Each pump functions as the primary, secondary and backup/emergency pump for the same number of hours during the monthly cycle. Adding control circuits enables one or more pumps to be added when necessary.