Offset Slider-Crank Diaphragm Pump for Balanced Piston Side Loads
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Solution Overview
Problem
Pneumatic diaphragm pumps are inefficient due to energy loss in converting high-pressure air to mechanical work and require additional equipment, making them costly and energy-inefficient for fluid transfer.
Innovation Solution
A diaphragm pump design with an electric motor-driven crankshaft and offset slider crank mechanism, featuring three pistons with non-intersecting axes of motion, balances piston side load forces and reduces energy consumption by eliminating reliance on pneumatic systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pneumatic drive is used to operate diaphragm pumps, then the pump can operate in potentially explosive environments and pressure can be controlled by air pressure, but energy efficiency deteriorates due to significant losses in creation, transport, and conversion of high-pressure gas to mechanical work
Solution Approach 1:
The patent replaces the pneumatic drive system with an electric motor-driven crankshaft mechanism. The electric motor directly drives the crankshaft, which converts rotational motion to reciprocating piston motion through the connecting rod and offset slider crank mechanism. This substitution eliminates the need for high-pressure air generation and transport, thereby resolving the energy efficiency problem while maintaining reliable operation.
2Ease of operation
If pneumatic drive is used to operate diaphragm pumps, then pressure control is simplified through air pressure regulation, but additional equipment (air compressor) and cost are required
Solution Approach 1:
The patent extracts and removes the air compressor and pneumatic system from the pump assembly, replacing them with a self-contained electric motor-driven mechanism. The electric motor and crankshaft assembly are integrated directly into the pump housing, eliminating the need for external air compression equipment and simplifying the overall system architecture.
3Device complexity
If conventional slider crank mechanism with intersecting axes is used, then the structure is simpler, but piston side load forces are unbalanced between suction and discharge strokes
Solution Approach 1:
The patent introduces an offset to the slider crank mechanism where the axis of motion of the piston does not intersect with the rotational axis of the crankshaft. This asymmetric configuration creates different leverage conditions during suction and discharge strokes, effectively balancing the piston side load forces. The offset distance is specifically designed to compensate for the force imbalance that would otherwise exist in a conventional symmetric slider crank mechanism.
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
The electric motor-driven design enhances energy efficiency, reduces piston side load forces, and minimizes pressure pulsations, providing stable fluid transfer with improved operational efficiency and reduced equipment costs.
Implementation Method 1
a crankshaft that is at least partially positioned within the crankcase and rotatable about a rotational axis
Implementation Method 2
A diaphragm pump design with an electric motor-driven crankshaft and offset slider crank mechanism
Implementation Method 3
positive displacement pumps that utilize diaphragms or pistons in connection with the intake, and subsequent discharge, of a fluid from a chamber of the pump
Implementation Method 4
the piston being reciprocally displaceable within a piston cylinder and along an axis of motion between a suction stroke and a discharge stroke
Implementation Method 5
A diaphragm housing can be coupled to an end of the piston cylinder, and can be configured to at least partially define a pumping chamber and pump fluid through the pumping chamber
Data Source
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AI summary
A diaphragm pump having a crankshaft that is rotatable about a rotational axis and coupled to a piston. The piston is reciprocally displaceable within a piston cylinder along an axis of motion between suction and discharge strokes. A diaphragm housing coupled to the piston cylinder at least partially defines a pumping chamber through which fluid is pumped as the piston reciprocates. The axis of motion, which intersects a connection between the piston and the connecting rod, may not intersect the rotational axis of the crankshaft such that, relative to an arrangement in which the axis of motion does intersect the rotational axis, a peak magnitude of piston side load forces during the discharge stroke is reduced and a peak magnitude of piston side load forces during the suction stroke is increased so as to attain an improved balance between the peak magnitudes of piston side load forces of the discharge and suction strokes.