Auxiliary Piston Diaphragm Pump for Rapid Pressure Build-up
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Solution Overview
Problem
Diaphragm metering pumps face challenges in quickly building up pressure during the phase between the closing of the suction valve and the opening of the pressure valve, especially in high-pressure applications, due to the low compressibility of hydraulic fluid and elasticities in the system, which limits the efficiency and precision of pumping small metering quantities.
Innovation Solution
The introduction of an auxiliary piston and chamber that allows additional hydraulic fluid to be introduced into the working chamber during the pressure build-up phase, assisted by a differential piston that combines the working and auxiliary pistons, enabling faster pressure increase by increasing the effective working surface area and reducing the necessary stroke length of the auxiliary piston.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the working piston has a small effective working surface area to precisely pump small metering quantities, then the metering precision is improved, but the pressure build-up time increases
Solution Approach 1:
The pressure build-up process is segmented into two phases: initial rapid pressure build-up using the auxiliary piston with large surface area, followed by precise metering using the working piston with small surface area. This segmentation allows each piston to optimize for its specific function without compromise.
Solution Approach 2:
The auxiliary piston performs preliminary action by rapidly building up pressure during the initial phase before the pressure valve opens. This preliminary pressure build-up eliminates the time delay that would otherwise occur with a small working piston alone, allowing the system to reach operational pressure faster.
2Speed
If the working piston stroke length is increased to build up pressure quickly, then the pressure build-up speed is improved, but the device dimensions increase
Solution Approach 1:
Two pistons with different surface areas are merged into a single cylinder assembly, allowing the system to combine the rapid pressure build-up capability of the auxiliary piston with the precise metering capability of the working piston, eliminating the need for a long stroke.
Solution Approach 2:
The system changes the effective surface area parameter dynamically by switching between auxiliary piston and working piston based on the operational phase. During initial pressure build-up, the large surface area of the auxiliary piston is used; during metering, the small surface area of the working piston is used.
3Loss of time
If the diaphragm speed is increased during pressure build-up phase, then the pressure build-up time is reduced, but the system stability decreases
Solution Approach 1:
The auxiliary piston automatically performs the pressure build-up function without requiring external control intervention. The system self-regulates by using the auxiliary piston's large surface area to rapidly establish pressure, eliminating the need for controlled acceleration that would compromise stability.
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 effectively reduces the pressure build-up phase without active pumping, allowing for quicker transition between suction and pressure phases, enhancing the efficiency and precision of pumping small volumes at high pressures.
Implementation Method 1
the auxiliary piston and the hollow auxiliary cylinder are formed and arranged in such a way that by moving the auxiliary piston within the hollow auxiliary cylinder, hydraulic fluid can at least partly be forced out of the additional chamber into the auxiliary channel and from the auxiliary channel into the working chamber
Implementation Method 2
because of the low compressibility of the hydraulic fluid, the change in the volume of the working chamber is small. The increase in the hydraulic fluid pressure does however cause the increased pressure to be transferred via the diaphragm onto the fluid being pumped
Implementation Method 3
The increase in the hydraulic fluid pressure does however cause the increased pressure to be transferred via the diaphragm onto the fluid being pumped located in the metering chamber, which in turn leads to a motion of the diaphragm
Implementation Method 4
If the diaphragm is moved in the suction direction, so that the volume of the metering chamber increases, the suction valve opens and fluid being pumped can be sucked via the suction line into the metering chamber. If the motion of the diaphragm is reversed, so that it is moved in the pressure direction, the pressure of the fluid being pumped in the metering chamber increases, with the result that first of all the suction valve closes
Data Source
AI summary
The invention relates to a device for generating a pulsating hydraulic fluid pressure in a working chamber (1) filled with hydraulic fluid, comprising a driveable working piston (4) movably guided in a hollow working cylinder, wherein a working chamber (1) that is in fluid communication with the working piston (4) is provided, such that, by means of the movement of the working piston (4) within the hollow working cylinder, a pulsating hydraulic fluid pressure can be generated in the working chamber (1). In order to provide a device for generating a pulsating hydraulic fluid pressure and in particular a diaphragm metering pump comprising such a device, which has small dimensions and in addition a rapid passage through the phase between closing the suction valve and opening the pressure valve, according to the invention, an auxiliary piston (20) is movably guided in a hollow auxiliary cylinder and is in fluid communication with an additional chamber (18, 21), wherein a closeable auxiliary channel (22), which connects the additional chamber (18, 21) and the working chamber (1), is provided, wherein the auxiliary piston (20) and the hollow auxiliary cylinder are formed and arranged in such a way that, by moving the auxiliary piston (20) within the hollow auxiliary cylinder, a hydraulic fluid arranged in the additional chamber (18, 21) can at least partly be forced out of the additional chamber (18, 21) into the auxiliary channel (22) and from the auxiliary channel (22) into the working chamber (1).