Oil flow switch and lubrication system with the same for a refrigeration system

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Solution Overview

Problem

Current oil level switches in refrigeration systems fail to accurately sense the oil level due to the presence of bubbles in the refrigerant oil solution, leading to false alarms and system malfunctions.

Innovation Solution

An oil flow switch with a float device and a floating liquid level switch element is introduced, where the float rises under buoyancy when oil flows and falls when it stops, ensuring the switch remains on only when oil is present in the circulating passage, preventing false alarms by maintaining the float chamber filled with oil.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a float level switch or photoelectric level switch is used to detect oil level, then the oil level can be monitored, but false alarms occur when bubbles are present in the refrigerant oil solution

Engineering Contradiction:
Improveoil level detection accuracyVSAvoidsignal accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The invention extracts the float mechanism from direct contact with the refrigerant oil solution containing bubbles. By placing the float inside a float chamber that is separated from the main oil passage, the float only interacts with pure oil introduced through the oil inlet, avoiding interference from bubbles in the refrigerant oil solution. This extraction resolves the contradiction by maintaining measurement precision while eliminating false alarms caused by bubble interference.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary mechanism - the float chamber - that mediates between the oil flow to be detected and the float level switch. The float chamber receives pure oil through the oil inlet and isolates the float from the bubbly refrigerant oil solution in the main passage. This intermediary structure allows accurate oil level detection without the float being affected by bubbles, thereby resolving the contradiction between measurement accuracy and signal reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the float chamber is directly exposed to the circulating oil passage, then the structure is simple, but bubbles in the oil solution cause the float to fail and generate false signals

Engineering Contradiction:
Improveswitch structure simplicityVSAvoidsignal accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention segments the oil detection system into two separate parts: the float chamber containing the float and level switch, and the main circulating oil passage. The float chamber is connected to the main passage through the oil inlet but remains structurally separate. This segmentation allows the float mechanism to operate in a controlled environment free from bubbles, while still monitoring the oil flow in the main passage, thus resolving the contradiction between structural simplicity and signal reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the float mechanism from the bubbly refrigerant oil solution environment by placing it inside a separate float chamber. The float chamber receives pure oil through the oil inlet, isolating the float from bubble interference. This extraction maintains functional simplicity while dramatically improving reliability by preventing false signals caused by bubbles affecting the float operation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If the float rises under buoyancy to indicate sufficient oil level, then the switch remains on for normal operation, but bubbles reduce oil density and prevent proper float operation

Engineering Contradiction:
Improveoil level sensing accuracyVSAvoidbubble interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the float from the harmful environment containing bubbles by placing it inside a separate float chamber. The float chamber receives pure oil through the oil inlet, eliminating bubble interference. This allows the float to rise accurately under buoyancy forces when sufficient oil is present, ensuring precise oil level sensing without the harmful effect of bubbles reducing oil density and preventing proper float operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces the float chamber as an intermediary that protects the float from bubble interference. The float chamber receives pure oil through the oil inlet and isolates the float mechanism from the bubbly refrigerant oil solution in the main passage. This intermediary structure enables accurate oil level sensing by allowing the float to respond only to pure oil density changes, eliminating the harmful effect of bubbles on float operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This solution effectively prevents false alarms caused by bubbles and ensures reliable oil level monitoring, maintaining system reliability by accurately indicating when the oil level is sufficient for operation.

Implementation Method 1

the float will float under the buoyancy force in the liquid, and will sink once the liquid level is insufficient

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

the oil in the float chamber will return to an oil pipe under the action of its gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3500806A1Oil flow switch and lubrication system with the same for a refrigeration system
Publication Date: 2019.06.26 JOHNSON CONTROLS AIR CONDITIONING & REFRIGERATION (WUXI) CO LTD

AI summary

The present disclosure relates to an oil flow switch, comprising a float device connected to a circulating oil passage and a floating liquid level switch element provided in the float device, wherein the float device comprises an oil inlet, an oil outlet, and a float chamber provided between the oil inlet and the oil outlet, the floating liquid level switch element is provided in the float chamber, and the float device is provided with a channel in communication with the float chamber. The oil flow switch according to the present disclosure may avoid a false alarm of the oil level switch and meanwhile mitigate disturbance to the float caused by liquid level fluctuation to reduce friction between the float and the sleeve rod. Further, a lubrication system with the above oil.