Variable Pressure Buffer for Pump Delivery Control
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Solution Overview
Problem
Existing methods for controlling the delivery pressure of viscous materials in metering systems face challenges such as wear and inaccuracy due to high pressures and pressure fluctuations, and are prone to failure with abrasive materials, while active pressure control systems suffer from inertia and inefficiency.
Innovation Solution
A method utilizing a pressure buffer with a variable buffer volume and a control unit that adjusts delivery pressure based on actual pressure values and the operating state of the metering pump, incorporating a PI or PID controller to mitigate pressure fluctuations and maintain constant pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a material pressure reducing valve is used to control the delivery pressure, then the inlet pressure to the metering pump is reduced to the required level, but the valve is very susceptible to failure, especially with abrasive materials causing rapid wear
Solution Approach 1:
A pressure buffer is introduced as an intermediary device between the supply pump and the metering pump. This buffer absorbs pressure fluctuations and decouples the high-pressure supply system from the metering pump, eliminating the need for fragile pressure reducing valves that are directly exposed to abrasive materials.
Solution Approach 2:
The pressure buffer is pre-filled with viscous material and designed to compensate for pressure variations before they reach the metering pump. This beforehand cushioning prevents pressure shocks and fluctuations from damaging the metering pump or requiring complex pressure control valves.
2Reliability
If active pressure control with a pressure sensor and control circuit is used, then the delivery pressure is regulated according to detected pressure, but the system inertia causes delayed response and pressure fluctuations during starting and stopping
Solution Approach 1:
The pressure buffer is pre-filled with viscous material before operation begins. This preliminary filling allows the buffer to immediately respond to pressure changes without waiting for material to flow through sensors and control circuits, eliminating the inertia delay inherent in active control systems.
Solution Approach 2:
The pressure buffer operates autonomously without requiring external control circuits or sensors. It self-regulates pressure fluctuations through its elastic deformation and the compressibility of the viscous material within the buffer, providing immediate pressure stabilization during starting and stopping operations.
3Productivity
If the supply pump operates at very high delivery pressure to compensate for pressure loss in the delivery line, then the viscous material can be delivered to the metering pump, but the pressure on the inlet side of the metering pump increases sharply when the metering pump stops
Solution Approach 1:
The pressure buffer serves as a mediator between the high-pressure supply pump and the metering pump. It absorbs excess pressure energy when the metering pump stops and releases it when needed, maintaining stable pressure at the metering pump inlet while allowing the supply pump to operate at higher delivery pressures.
Solution Approach 2:
The pressure buffer utilizes changes in the compressibility and volume of the viscous material to absorb and release pressure energy. By changing the physical state and volume of the material within the buffer, it stabilizes pressure fluctuations without requiring changes in the supply pump's delivery pressure.
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 approach reduces extreme pressure fluctuations, enhances metering accuracy, and allows for reliable operation with abrasive materials, offering a cost-effective and flexible solution with reduced equipment size and weight compared to traditional methods.
Implementation Method 1
a pressure buffer which is pretensioned to a pretensioning pressure P and has a variable buffer volume... the buffer volume can receive viscous material from the delivery line when the delivery pressure in the delivery line in the region of the pressure buffer is higher than the pretensioning pressure P of the pressure buffer
Implementation Method 2
a pressure buffer which is pretensioned to a pretensioning pressure P... Viscoelasticity
Implementation Method 3
a pressure sensor, connected upstream of the inlet of the metering pump for detecting the actual pressure value in the delivery line, and a control unit... the control unit transmits a specification value to the supply pump, depending upon a deviation between a specified target pressure value and the actual pressure value
Data Source
AI summary
Methods for controlling supply pump delivery pressure in a system having a supply pump, a metering pump, a delivery line extending between them where the supply pump delivers material through the delivery line to a metering pump inlet; and a pretensioned pressure buffer of variable buffer volume is connected upstream of the metering pump inlet, the buffer volume capable of receiving material from the delivery line when delivery line pressure near the pressure buffer is >pretensioning pressure P of the pressure buffer and capable of dispensing material to the delivery line when delivery line pressure near the pressure buffer is <the pretensioning pressure P; the system may also include a pressure sensor and a control unit, connected to the sensor, supply pump, and metering pump, which transmits a value to the supply pump based on metering pump status and delivery line actual pressure deviation from target pressure.