Twin Piston Pump Cam Mechanism for Paint Pulsation
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Solution Overview
Problem
Existing paint pumping systems, such as those using air motors, are inefficient in energy utilization and exhibit noticeable pulsation due to slow drive direction changes, and complex control arrangements are required for electric motor-driven systems.
Innovation Solution
A twin opposed piston reciprocating pump driven by an alternating current (A.C.) electric motor, utilizing a constant velocity cam and cam follower mechanism to convert rotary motion into reciprocal motion, with pistons 180° out of phase, and optionally additional pistons 90° out of phase, to supply liquid paint to a pressure loop with reduced pulsation and simplified control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an air motor is used to drive reciprocating pistons, then the pump can operate with simple structure, but energy utilization becomes inefficient and pulsation increases due to slow drive direction change
Solution Approach 1:
The patent replaces the air motor (pneumatic system) with an electric motor, substituting one mechanical drive system with another that offers superior energy efficiency. The electric motor directly drives the cam mechanism without the energy losses associated with compressed air systems, thereby improving energy utilization while maintaining operational simplicity.
Solution Approach 2:
The invention changes the operating parameters of the drive system by using an electric motor that can rapidly change rotation direction, unlike air motors which have slow response times. This parameter change in drive speed and direction change rate eliminates pulsation while improving energy efficiency.
2Device complexity
If an air motor drives reciprocating pistons, then the pump structure remains simple, but pulsation increases due to slow drive direction change
Solution Approach 1:
The electric motor replaces the air motor, providing a drive system that can rapidly change rotation direction. This substitution eliminates the slow response characteristic of air motors that causes pulsation, thereby stabilizing the pump output while keeping the overall structure simple through direct coupling to the cam mechanism.
Solution Approach 2:
The invention changes the dynamic parameters of the drive system by using an electric motor with fast response capability. This allows rapid direction changes without the inertia and pressure buildup issues of air motors, stabilizing the reciprocating motion and eliminating pulsation in the paint supply.
3Productivity
If a D.C. electric motor with large stroke piston is used, then pump output is improved, but control system complexity and cost increase
Solution Approach 1:
The patent replaces the complex D.C. electric motor control system with a simpler A.C. motor drive through cam mechanism. The cam profile mechanically defines the piston motion, eliminating the need for complex electronic controls while maintaining large stroke capability and high output.
Solution Approach 2:
The cam mechanism acts as an intermediary between the simple A.C. motor and the piston. It translates the simple rotary motion of the A.C. motor into the required large-stroke reciprocating motion, achieving high productivity without complex control arrangements.
4Device complexity
If conventional reciprocating pump design is used, then structure is simple, but pulsation occurs in paint supply
Solution Approach 1:
The patent uses two opposed pistons working in parallel, segmenting the pump output into two streams. When one piston is delivering paint, the other is drawing it in, and vice versa. This segmentation smooths out the pulsations inherent in single-piston reciprocating pumps, providing more stable paint supply while keeping the structure relatively simple.
Solution Approach 2:
The invention employs periodic action of two pistons operating 180° out of phase. As one piston completes its discharge stroke, the other begins its discharge stroke. This periodic alternation ensures continuous, pulsation-free paint delivery to the spray gun while maintaining simple reciprocating mechanics.
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 provides a more efficient and stable paint supply with reduced energy consumption and pulsation, enabling constant paint pressure and simplified control, suitable for use with spray guns.
Implementation Method 1
a constant velocity cam and cam follower mechanism converting rotary motion of the output shaft into reciprocatory motion of said first and second pistons 180° out of phase with one another
Implementation Method 2
an A.C. electric motor the rotary output shaft of which is coupled to said first and second pistons
Implementation Method 3
a gearbox is interposed between the output shaft of the motor and said constant velocity cam or cams
Implementation Method 4
If desired a flywheel can be associated with the drive transmission between the A.C. motor output shaft and the or each constant velocity cam
Data Source
AI summary
A pump primarily for liquid paint includes first and second pistons reciprocable rectilinearly in respective first and second cylinders. The first and second pistons are moved relative to their respective pistons by operation of an A. C. electric motor the rotary output shaft of which is coupled to the first and second pistons by a constant velocity cam and a cam follower mechanism converting rotary motion of the output shaft into reciprocatory motion of the first and second pistons 180° out of phase with one another.