Rotary Compressor Backflow Valve Layout for Check Valve Failure Detection
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Solution Overview
Problem
Existing rotary displacement compressors face issues with backflow of compressed air when the compressor stops, leading to noise and potential damage due to reverse rotation of rotary parts, and the failure of check valves makes it difficult to determine if the second check valve has malfunctioned, causing reduced compressor life.
Innovation Solution
A rotary displacement compressor design that includes a backflow control valve connected in series with the check valve, limiting the flow rate of backflow without completely shutting it off, allowing a small rate of compressed air to flow back and reducing the risk of damage from centrifugal force, while enabling detection of check valve failures through motor voltage or current monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a check valve is provided to prevent backflow of compressed air, then the compressor body is protected from damage, but the check valve may fail undetected and cause reverse rotation of rotary parts
Solution Approach 1:
The patent implements a feedback mechanism by monitoring motor voltage or current to detect check valve failures. When the check valve fails and backflow occurs, the motor experiences abnormal electrical parameters during reverse rotation, which are detected and used to alert operators of the valve failure.
Solution Approach 2:
The patent introduces an intermediary detection system that monitors the motor's electrical parameters as an intermediate indicator of check valve health. Instead of directly monitoring the check valve, the system uses motor voltage or current as an intermediary signal to infer the valve's operational status.
2Object-affected harmful factors
If the check valve completely shuts off backflow, then reverse rotation is prevented, but undetected failure leads to uncontrolled reverse rotation and noise
Solution Approach 1:
The monitoring system provides feedback about the check valve's operational status by detecting abnormal motor electrical parameters during reverse rotation, enabling timely detection and response to valve failures that cause noise and damage.
3Reliability
If the check valve is positioned before the aftercooler, then backflow prevention is immediate, but the check valve suffers heat-induced deterioration
Solution Approach 1:
The patent changes the spatial dimension of valve placement by positioning the check valve after the aftercooler instead of before it. This dimensional repositioning in the flow path allows the valve to operate in a cooler environment, reducing thermal deterioration while maintaining backflow prevention functionality.
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
Prevents compressor body damage and allows for the determination of check valve failures, while avoiding heat-induced deterioration of the check valve by positioning it behind the aftercooler, ensuring continued operation and extended compressor life.
Implementation Method 1
an aftercooler that cools the compressed air discharged from the compressor body
Implementation Method 2
a check valve that shuts off compressed air flowing backward to the compressor body
Implementation Method 3
a backflow control valve that allows a predetermined rate of the compressed air to flow backward without completely shutting off the backflow
Data Source
Figure 1~2
Figure 3(A)~3(B)
Figure 4(A)~4(C)
AI summary
An object of the present invention is to provide a rotary displacement compressor capable of determining whether a check valve has failed, and preventing the life of a compressor body from being reduced when a compression operation stops. In order to achieve the object, a rotary displacement compressor includes a compressor body that compresses a medium by reducing a volume of the medium using rotation; a discharge pipe through which a compressed medium, which is discharged through a discharge port of the compressor body, flows; a check valve that shuts off the compressed medium flowing backward to the compressor body; and a backflow control valve that allows a predetermined rate of the compressed medium to flow backward. The check valve and the backflow control valve are disposed in series via the discharge pipe.