Flow Rate Control Valve for Pump Switching Pressure Stability
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Solution Overview
Problem
In a fuel supply system with a centrifugal pump and a starting pump connected in series, rapid pressure changes upstream of the measuring valve occur when switching between the two pumps, leading to potential pulsation in the measurement flow rate due to differential pressure differences.
Innovation Solution
A flow rate control valve is provided between the discharge port of the centrifugal pump and the suction port of the starting pump, with a valve opening speed 1/5 to 1/10 of the differential pressure valve, to gradually introduce fuel from the centrifugal pump, thereby slowing the change in flow rate and pressure upstream of the measuring valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the flow rate control valve opens quickly to switch from starting pump to centrifugal pump, then the switching time is reduced and productivity is improved, but rapid pressure changes occur upstream of the measuring valve causing measurement precision to deteriorate
Solution Approach 1:
The flow rate control valve transitions from a static fully-open/closed state to a dynamic controlled-opening state. The valve opening degree is dynamically adjusted based on the running states of the starting pump and centrifugal pump, allowing the system to smoothly transition between pump modes while maintaining stable pressure upstream of the measuring valve.
Solution Approach 2:
The control device receives feedback signals from both the starting pump and centrifugal pump running states, and automatically adjusts the flow rate control valve opening degree accordingly. This feedback mechanism ensures that the valve opening speed is coordinated with pump switching, preventing rapid pressure changes that would affect measurement accuracy.
2Speed
If the flow rate control valve opening speed is increased to reduce switching time, then the response time is improved, but pressure stability upstream of the measuring valve deteriorates causing pulsation in measurement
Solution Approach 1:
The flow rate control valve transitions from a static fully-open/closed state to a dynamic controlled-opening state. The valve opening degree is dynamically adjusted based on the running states of the starting pump and centrifugal pump, allowing the system to smoothly transition between pump modes while maintaining stable pressure upstream of the measuring valve.
Solution Approach 2:
The flow rate control valve is opened in advance during the pump switching process to cushion the pressure changes. By controlling the valve opening speed to be slower than the pump switching speed, the system prepares for pressure changes before they occur, preventing rapid pressure fluctuations that would cause measurement pulsation.
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 configuration suppresses rapid pressure changes and prevents pulsation in the measurement flow rate, allowing for accurate measurement by maintaining a stable pre-measurement pressure during the switch from the starting pump to the centrifugal pump.
Implementation Method 1
a flow rate control valve 5, wherein a valve opening speed of the flow rate control valve 5 is slower than a valve opening speed of the differential pressure valve 8a
Implementation Method 2
a differential pressure valve 8a that opens in response to a pressure differential across the measuring valve 7
Data Source
Figure 1
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AI summary
A fluid supply system (1) includes: a centrifugal pump (2); a starting pump (4) that is connected to the centrifugal pump (2) in series, is provided downstream of the centrifugal pump (2), and has a discharge flow rate less than that of the centrifugal pump (2); a measuring valve (7) that is provided downstream of the centrifugal pump (2) and the starting pump (4), measures an amount of fluid discharged from the centrifugal pump (2) or the starting pump (4), and discharges the fluid to a downstream each time the fluid reaches a predetermined flow amount; a differential pressure valve (8a) that is provided downstream of the centrifugal pump (2) and the starting pump (4), and is driven based on a differential pressure between an upstream pressure and a downstream pressure of the measuring valve (7); and a flow rate control valve (5) that is provided downstream of the centrifugal pump (2) and upstream of the differential pressure valve (8a) and has a valve opening speed that is set slower than that of the differential pressure valve (8a).