Rotating Reciprocating Piston Pump Barrel Cam Mechanism
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Solution Overview
Problem
Rotating reciprocating piston pumps (RRP) are expensive and inefficient due to mechanical coupling complexities and continuous piston linear travel, causing unwanted fluid pulses and pressure inefficiencies.
Innovation Solution
A metering pump assembly with a piston aligned with the motor shaft axis, using barrel cam halves and a cam follower pin to generate reciprocal motion without angling the piston, and a D-shaped piston cross-section to seal ports, reducing mechanical complexity and pressure inefficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the piston is angled with respect to the motor shaft to generate reciprocal motion, then the pump can deliver volumetric flow, but the mechanical coupling becomes expensive and complex
Solution Approach 1:
Instead of angling the piston relative to the motor shaft to generate reciprocating motion, the patent inverts the approach by keeping the piston parallel to the motor shaft and using an off-center cam mechanism to generate the reciprocating motion. This inversion simplifies the mechanical coupling while maintaining volumetric flow capability.
Solution Approach 2:
The patent introduces a cam mechanism as an intermediary element between the motor shaft and the piston. The cam converts the rotational motion of the motor shaft into reciprocating motion of the piston without requiring the piston to be angled, thereby simplifying the mechanical coupling while enabling volumetric flow.
2Duration of action of moving object
If the piston linear travel is continuous, then the piston can complete its stroke, but negative and positive pressures are trapped causing inefficiency and fluid pulses
Solution Approach 1:
The patent implements periodic action by using the cam mechanism to create a motion profile where the piston has periods of acceleration and deceleration. The cam geometry is designed to allow the piston to dwell or slow down at the extremes of its stroke, preventing pressure trapping and reducing fluid pulses while maintaining continuous stroke capability.
3Ease of operation
If the piston is angled with respect to the motor shaft, then reciprocal motion is generated, but the mechanical coupling is expensive
Solution Approach 1:
The patent uses a cam profile that copies or replicates the desired reciprocating motion pattern. Instead of achieving reciprocating motion through complex angled piston-m shaft coupling, the cam surface is shaped to guide the follower through the required motion path, providing a simpler and more cost-effective manufacturing approach.
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 solution reduces costs, eliminates fluid pulses, and enhances volumetric accuracy by maintaining piston alignment and using rotational dwell to manage port openings, improving overall pump efficiency and precision.
Implementation Method 1
a cam follower pin, wherein the cam follower pin is positioned within a peripheral slot between the first barrel cam half and the second barrel cam half, wherein the first barrel cam half and the second barrel cam half are connected to the piston, wherein rotational movement of the motor shaft directly imparts rotational movement upon the piston and indirectly imparts reciprocal movement of the piston through movement of the cam follower pin within the peripheral slot
Data Source
AI summary
Provided is a metering pump. The metering pump includes a motor and a motor shaft and a pump housing having an inlet port and an outlet port. Encased within the pump housing and engaged to the motor shaft is a piston. The motor shaft imparts rotational movement upon the piston. The metering pump further includes two barrel cam halves engaged to the piston. Between the two barrel cam halves is a cam follower pin which in combination with the two barrel cam halves allows the piston to move in a reciprocating manner upon rotation of the motor shaft. Thus, the piston is capable of moving in both a rotational and reciprocating manner along the same axis.