Centrifugal Pump Air Venting via Speed Cycling
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Solution Overview
Problem
Centrifugal pump assemblies in house water systems experience operational failures due to air or gas accumulations, which can lead to reduced throughput and pressure, as these accumulations can become too large and disrupt the pump's functionality.
Innovation Solution
A centrifugal pump assembly with a back-flow channel and a control unit that automatically reduces and then rapidly increases the motor speed to flush out air or gas accumulations, utilizing a pressure-dependent valve and monitoring electrical power consumption to detect and address issues before they cause operational failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump operates continuously to maintain water flow and pressure, then productivity is improved, but air or gas accumulations build up causing operational failure
Solution Approach 1:
The pump operates in periodic cycles, alternating between normal operation mode and venting mode. During normal operation, water is pumped continuously. When air/gas accumulation is detected (via pressure drop or power consumption monitoring), the pump switches to venting mode where the back-flow channel opens to remove accumulations, then returns to normal operation. This periodic switching resolves the contradiction by maintaining productivity while periodically eliminating reliability-threatening accumulations.
2Reliability
If the pump speed is reduced to vent air accumulations, then reliability is improved, but pressure and flow in the water system decrease
Solution Approach 1:
The pump speed is dynamically adjusted based on operational needs. During normal operation, the pump runs at full speed to maintain water flow and pressure. When venting is required, the speed is temporarily reduced to allow the back-flow channel to open and remove air accumulations. After venting, the speed is rapidly increased again to restore pressure and flow. This dynamic speed control resolves the contradiction by temporarily sacrificing productivity to maintain reliability, then rapidly recovering productivity.
Solution Approach 2:
The speed reduction for venting is kept brief and minimal, rushing through the venting process quickly rather than maintaining reduced speed. The pump rapidly transitions from normal speed to reduced speed for venting, then immediately ramps back to full speed. This minimizes the time during which pressure and flow are reduced, resolving the contradiction by making the productivity sacrifice as short-lived as possible while still achieving reliable venting.
3Reliability
If a back-flow channel is added to enable self-priming and air venting, then reliability and ease of operation are improved, but device complexity increases
Solution Approach 1:
The back-flow channel serves multiple functions simultaneously: it enables self-priming by allowing fluid to be delivered in the circuit during startup, provides a venting path for air and gas accumulations during operation, and facilitates rapid pressure recovery after venting. By making this single structural element multi-functional, the patent resolves the contradiction by achieving multiple reliability improvements without proportionally increasing complexity.
Solution Approach 2:
The back-flow channel with pressure-dependent valve enables the pump to automatically vent its own air accumulations without external intervention. The valve opens automatically when pressure drops indicate air presence, allowing the pump to self-correct the air accumulation problem. This self-service capability improves reliability while minimizing the need for additional complex control systems or manual intervention mechanisms.
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 solution allows for the removal of air or gas accumulations during operation without significant functional restrictions, maintaining adequate pressure and flow in the water system, with minimal speed reduction and rapid pressure recovery, thus preventing operational failures and ensuring continuous system performance.
Implementation Method 1
at least one impeller which is driven in rotation by an electrical drive motor
Implementation Method 2
centrifugal pump assembly which comprises at least one impeller which is driven in rotation
Implementation Method 3
A valve which closes the back-flow channel or the flow connection created by this, in a pressure-dependent manner, is arranged in the back-flow channel
Implementation Method 4
An intense flow is produced by way of this rapid speed increase, by way of which flow the gas bubbles or the gas accumulations can be flushed out of the centrifugal pump assembly
Data Source
AI summary
A centrifugal pump assembly (2) includes an impeller, an electric drive motor (4), driving the impeller (12), and a back-flow channel (24), forming a flow connection from a delivery side (18) to a suction side (16). A valve (26), in a pressure-dependent manner, closes the flow connection. A control device (28) adjusts/sets the speed (n) of the drive motor (4), and is configured with a venting function for venting the centrifugal pump assembly (2) on operation. According to the venting function, after the detection of an air accumulation, the speed (n) of the drive motor (4) is automatically reduced, and subsequently the speed (n) is rapidly increased again. A method is also provided for removing an air accumulation from a centrifugal pump assembly during operation, which method includes reducing the speed (n) of the centrifugal pump assembly and subsequently rapidly increasing the speed (n) of the centrifugal pump again.