Self-ventilating Wet Rotor Pump Using Semipermeable Membrane

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Wet rotor pumps with vertical pump shafts experience inadequate ventilation, leading to air collection and inadequate lubrication of the upper plain bearing, which can result in damage due to insufficient air being sucked out of the rotor chamber.

Innovation Solution

Incorporating a semi-permeable membrane between the rotor space and the atmosphere, allowing air to escape while retaining liquid, which is arranged at an axial end of the rotor chamber, eliminating the need for a hollow shaft and filter, and ensuring reliable ventilation even with a vertical pump shaft.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hollow shaft with internal filter is used to extract air from the rotor chamber, then air venting is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improveair venting effectivenessVSAvoidshaft structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the air venting function from the hollow shaft structure and relocates it to a separate semipermeable membrane component. This separates the venting function from the shaft, eliminating the need for a complex hollow shaft with internal filters while maintaining effective air removal from the rotor chamber.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The semipermeable membrane acts as an intermediary component that enables air to pass through while blocking liquid. This membrane provides a simple and effective air venting path without requiring the complex hollow shaft structure, thereby reducing device complexity while maintaining reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If manual venting using a vent screw is used, then air can be removed from the rotor chamber, but operation complexity and potential damage from inadequate venting increase

Engineering Contradiction:

Improveair removal capabilityVSAvoidventing operation simplicity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The semipermeable membrane provides automatic, self-regulating air venting based on pressure differential. Air is drawn through the membrane when pressure inside the rotor chamber exceeds atmospheric pressure, eliminating the need for manual vent screw operation. This self-service mechanism ensures reliable air removal while simplifying operation.

Inventive Principle:

Principle #25Self-service

3Temperature

If the pump shaft is made hollow to enable fluid flow through it, then cooling effect is improved, but the need for expensive internal filters increases device complexity

Engineering Contradiction:

Improvestator cooling effectVSAvoidshaft internal filter requirement

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

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 semi-permeable membrane enables automatic and reliable ventilation of the rotor chamber, preventing air collection and ensuring proper lubrication of all bearings, thus enhancing the operational reliability and longevity of the wet rotor pump.

Implementation Method 1

A semipermeable membrane is arranged between the rotor chamber and the atmosphere outside the wet rotor pump. This membrane is designed to allow air to pass through while retaining the liquid.

Methodology Applied

Scientific EffectSemipermeable membrane: Semipermeable Membrane

Implementation Method 2

any air introduced into the rotor chamber can escape automatically and reliably at any time. This is due to the overpressure existing in the rotor chamber relative to the atmosphere.

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP4001654B1Self-ventilating wet rotor pump

Publication Date: 2024.07.17 WILO SE

Figure 1~1a
Figure 1b~1c
Figure 2

AI summary

The invention relates to a wet rotor pump (1) for pumping a liquid, comprising a rotor chamber (14) filled with the liquid, in which a rotor (3) is rotatably arranged and which is separated from a stator (4) in a liquid-tight manner by a canned tube (5). A semipermeable membrane (17a, 17b, 17c) is arranged between the rotor chamber (14) and the atmosphere outside the wet rotor pump (1), which is designed to allow air to pass through and retain the liquid. Thus, automatic venting is effected during operation of the wet rotor pump.