Diaphragm Position Control in Hydraulically Driven Pumps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hydraulically driven diaphragm pumps face limitations in using highly flexible elastomeric diaphragms capable of large deflections, leading to increased pump size and cost, and inefficiencies in pressure management, particularly in asynchronous and synchronous pumps, due to unbalanced pressure drops and material stress.
Innovation Solution
A diaphragm pump design featuring a movable valve spool that controls fluid flow between a transfer chamber and a fluid reservoir based on volume conditions, rather than pressure, to maintain proper diaphragm position and prevent overfill or underfill, using check valves to allow fluid exchange only when conditions arise, thereby reducing material stress and enabling smaller, more flexible diaphragm usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If asynchronous pump design with long stroke piston is used, then pump size can be reduced, but diaphragm experiences unbalanced pressure and material stress
Solution Approach 1:
A volume compensating device is introduced as an intermediary between the piston and diaphragm. This device includes a compensating piston, compensating chamber, and check valves that mediate the pressure transmission, allowing the long stroke piston to operate while protecting the diaphragm from unbalanced pressure stresses.
Solution Approach 2:
The system changes the parameter of pressure transmission by using a compensating mechanism that decouples the direct pressure relationship between piston and diaphragm. The compensating volume adjusts the hydraulic fluid volume dynamically, transforming the direct pressure-stress relationship into a controlled volume compensation process.
2Device complexity
If synchronous pump design with short stroke piston is used, then diaphragm position control is simplified, but crankshaft and crankcase experience higher loads
Solution Approach 1:
The system transitions from a static synchronous connection (where piston stroke equals diaphragm stroke) to a dynamic asynchronous connection. The compensating volume device dynamically adjusts the hydraulic fluid volume based on actual diaphragm position and pump operating conditions, allowing the piston to have a longer stroke while the diaphragm maintains proper positioning.
Solution Approach 2:
The compensating mechanism provides feedback control where the check valves and compensating chamber respond to pressure and volume conditions, automatically adjusting the hydraulic fluid volume to maintain optimal diaphragm positioning without requiring complex mechanical position control mechanisms.
3Productivity
If highly flexible elastomeric diaphragms with large deflection capability are used, then pump efficiency improves, but pump size and cost increase
Solution Approach 1:
The system segments the pump into two independent but coordinated systems: a long-stroke hydraulic drive system and a flexible diaphragm pumping system. The compensating volume device acts as the coupling mechanism, allowing each component to be optimized independently - the piston for efficiency and the diaphragm for flexibility - without compromising overall pump size.
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 use of small, flexible elastomeric diaphragms in both synchronous and asynchronous pumps, reducing pump size and cost while effectively managing fluid pressure imbalances, minimizing wear, and preventing diaphragm failure under extreme conditions.
Implementation Method 1
A hydraulically driven diaphragm pump includes a piston adapted for reciprocal movement between a first position and a second position, a diaphragm movable between first and second positions that correlate with the first and second piston positions
Implementation Method 2
using check valves to allow fluid exchange only when conditions arise, thereby reducing material stress and enabling smaller, more flexible diaphragm usage
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A liydraulically driven pump includes a diaphragm, a piston, a transfer chamber, a fluid reservoir, and a spool member. The transfer chamber is defined between the diaphragm and piston and is filled with a hydraulic fluid. The fluid reservoir is in fluid communication with the transfer chamber via at least one valve. The spool member is configured to control fluid flow between the transfer chamber and the fluid reservoir. The spool member is movable to open and close an opening into the at least one valve only when an overfill condition or an underfill condition exists in the transfer chamber.