Screw-Driven Piston Pump for Long Stroke and Failure Detection
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Solution Overview
Problem
Existing fluid delivery systems, particularly paint pumps, face challenges with torque limitations, bending moments, and inefficiencies in piston movement, leading to issues like rapid cycling that prevent timely detection of mechanical failures.
Innovation Solution
A screw-driven pump system utilizing a unidirectional electric motor and a self-reversing screw mechanism to convert rotational motion into linear reciprocation, allowing for longer stroke lengths, reduced wear, and improved diagnostic capabilities through current sensing, with optional use of accumulators and self-priming circuits to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a traditional piston pump mechanism is used, then fluid delivery is achieved, but torque limitations and bending moments restrict stroke length and cause rapid cycling
Solution Approach 1:
The patent replaces the traditional mechanical piston pump mechanism with a screw-driven system where a rotating screw moves a nut linearly to drive the piston. This substitution eliminates the torque limitations and bending moments of traditional mechanisms, enabling longer stroke lengths while reducing wear and improving reliability. The screw mechanism converts rotational motion to linear motion efficiently, allowing extended strokes without the mechanical constraints of conventional piston pumps.
2Productivity
If rapid cycling is used to increase productivity, then fluid delivery rate improves, but mechanical failures cannot be detected timely
Solution Approach 1:
The patent incorporates current sensing capability that monitors motor current to detect mechanical issues such as increased friction or wear in the screw-nut mechanism. This feedback system allows early detection of mechanical failures even during rapid cycling, maintaining high productivity while improving reliability through continuous monitoring and diagnostic capability.
3Device complexity
If a unidirectional electric motor is used, then system simplicity improves, but conversion to reciprocating motion requires additional mechanism
Solution Approach 1:
The patent uses a screw-nut mechanism as an intermediary between the unidirectional electric motor and the piston. The screw converts the motor's unidirectional rotation into linear motion of the nut, which then drives the piston reciprocally. This intermediary mechanism achieves complex reciprocating motion from a simple unidirectional motor, maintaining system simplicity while enabling effective piston operation.
4Duration of action of stationary object
If longer stroke length is implemented, then wear is reduced, but mechanism complexity increases
Solution Approach 1:
The screw-nut mechanism serves multiple functions simultaneously: it converts rotational to linear motion, enables long stroke lengths, provides mechanical advantage for force multiplication, and creates a self-locking mechanism that prevents backflow. This multi-functionality achieves extended component service life through reduced wear while avoiding additional complexity, as a single mechanism accomplishes what would otherwise require multiple components.
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 screw-driven pump system offers increased durability, efficiency, and the ability to detect mechanical issues early, while eliminating the need for biasing valves and reducing dead band during piston direction changes, thus enhancing fluid delivery precision and reliability.
Implementation Method 1
a screw drive coupled to the electric motor. The screw drive is configured to convert the unidirectional rotational output of the electric motor into reciprocating motion to linearly reciprocate a piston
Data Source
AI summary
A fluid pump comprises an electric motor configured to provide a unidirectional rotational output. The fluid pump further comprises a screw drive coupled to the electric motor. The screw drive is configured to convert the unidirectional rotational output of the electric motor into reciprocating motion. The screw drive comprises a piston rod, a nut, and a connection assembly configured to couple the piston rod to the nut such that the piston rod is linearly reciprocated with the nut.