Rotary Displacement Pump Rectifier Gear Mechanism

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Solution Overview

Problem

Rotating displacement pumps, particularly screw pumps, face issues with severe wear and product stress due to incorrect direction of rotation, which can lead to reduced service life and contamination in hygienic applications like the food and cosmetics industry, and existing solutions are inefficient and complex.

Innovation Solution

A rotary displacement pump with a rectified gear system that maintains constant output rotation direction regardless of input motor rotation, utilizing two gear trains with overrunning clutches and different gear ratios to allow for reversible operation without manual intervention, ensuring proper direction and expanding speed ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the pump is driven in the wrong direction of rotation, then the motor can be operated in reverse, but the pump suffers severe wear, reduced service life, and product contamination

Engineering Contradiction:

Improvereversible motor operationVSAvoidpump service life and product purity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A rectifier gear mechanism is introduced as an intermediary between the motor and the working shafts. This rectifier gear includes a first gear train and a second gear train that convert the motor's rotation in either direction into unidirectional rotation of the working shafts, thereby protecting the pump from damage while allowing reversible motor operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The two gear trains in the rectifier gear are designed with different gear ratios, creating an asymmetric transmission system. This asymmetry ensures that regardless of the motor's rotation direction, the working shafts always rotate in the correct direction with appropriate speed ratios for the displacement bodies to operate without contact

Inventive Principle:

Principle #4Asymmetry

2Reliability

If a complex rectifier gear with two gear trains routed to the same output shaft is used, then the rotation direction is rectified, but the structure becomes complex and energy transmission efficiency is impaired

Engineering Contradiction:

Improveconstant output rotation directionVSAvoidgear structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The rectifier gear is segmented into two independent gear trains, each with different gear ratios. The first gear train is connected to the first working shaft and the second gear train to the second working shaft. This segmentation allows each gear train to be optimized independently and simplifies the overall structure compared to routing both trains to a single output shaft

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of routing both gear trains to the same output shaft as in conventional designs, the patent inverts the approach by connecting each gear train to a separate working shaft. This inversion simplifies the mechanical structure and improves energy transmission efficiency while still achieving the rectification function through the synchromesh gear coupling

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If the gear trains have the same number of gears, then the structure is simplified and manufacturing is easier, but the speed range adjustment capability is limited

Engineering Contradiction:

Improvegear train symmetryVSAvoidspeed range adjustment

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

While maintaining the same number of gears in each train for structural symmetry and ease of manufacture, the patent varies the gear ratios between the two gear trains. This parameter change allows different speed ranges to be achieved for the two working shafts, providing adaptability for different operating conditions while keeping the manufacturing process simple

Inventive Principle:

Principle #35Parameter changes

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 prevents pump damage and contamination by maintaining consistent rotation direction, simplifies the gear structure, and allows for two-speed operation with reversible motor direction, enhancing efficiency and reliability in hygienic applications.

Implementation Method 1

The first gear train and the second gear train each include at least one overrunning clutch. The overrunning clutch of the first gear train is arranged such that the first gear train only transmits the torque of the motor when the motor is rotating in a first direction of rotation.

Methodology Applied

Scientific EffectOverrunning clutch mechanism: Ratchet

Implementation Method 2

the synchromesh is set up to rotate the first and the second working shaft in opposite directions

Methodology Applied

Scientific EffectGear meshing: Gear

Data Source

PatentEP3575549B1Rotary displacement pump

Publication Date: 2022.03.30 FRISTAM PUMPEN SCHAUMBURG GMBH

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Figure 3a~3b

AI summary

A rotary positive displacement pump is presented, comprising at least two synchronously driven displacement bodies arranged on associated working shafts (40, 41), the working shafts (40, 41) being coupled to each other by a synchronous transmission. The positive displacement pump is characterized by the inclusion of a rectifying transmission (30).