Flow Restrictor Tube for Chiller Water Flow Measurement
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Solution Overview
Problem
In chiller systems, fluid flow rate measurement devices often inaccurately detect water flow rates due to turbulence and sensor variability, leading to unnecessary shutdowns when the measured flow is above the intended trip point, known as 'nuisance trips', which can occur due to extraneous factors like pump malfunctions or partial freezing.
Innovation Solution
A flow restrictor tube is integrated within the water pipe to reduce turbulence and flow variability, allowing water to flow at a reduced rate, and a measuring probe is positioned to measure this reduced flow rate within the accuracy range, enhancing measurement accuracy and preventing unnecessary system shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a measuring probe is used to detect water flow rate in the water pipe, then the chiller system can monitor water flow and prevent freezing, but turbulence and sensor variability cause inaccurate measurements leading to unnecessary shutdowns
Solution Approach 1:
A flow restrictor tube is introduced as an intermediary component between the water pipe and the measuring probe. This restrictor tube serves as a mediator that conditions the water flow before it reaches the sensor, reducing turbulence and flow variability to improve measurement accuracy while maintaining the ability to detect low flow conditions
Solution Approach 2:
The flow restrictor tube changes the flow parameters (velocity, turbulence level, flow profile) of the water before it reaches the measuring probe. By reducing the flow rate and smoothing turbulence through the restrictor tube, the measurement conditions are optimized for the probe's accuracy range
2Measurement precision
If the measuring probe measures water flow rate directly in the water pipe, then the system can detect low flow conditions, but high variability and turbulence cause false readings above the trip point
Solution Approach 1:
The flow restrictor tube acts as a mediator that conditions the water flow before it reaches the measuring probe, reducing turbulence and flow variability. This intermediary structure ensures that the probe receives stabilized flow conditions that reflect true low-flow conditions without false readings
Solution Approach 2:
The flow restrictor tube performs preliminary action by pre-conditioning the water flow before it reaches the measuring probe. It reduces turbulence and flow variability in advance, ensuring that the measurement taken by the probe is accurate and reliable before the system makes shutdown decisions
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 improves the accuracy of fluid flow rate measurements, reducing 'nuisance trips' by ensuring that the chiller system shuts down only when the water flow is insufficient to prevent freezing, thereby maintaining system reliability and preventing unnecessary restarts.
Implementation Method 1
the flow restrictor tube reduces turbulence, which can reduce local flow variability and enhance flow measurement accuracy
Implementation Method 2
a measuring probe that passes through walls of the water pipe and walls of the flow restrictor tube and includes an accuracy range of flow rates less than the water flow rate
Implementation Method 3
an evaporator for evaporating a refrigerant
Implementation Method 4
circulating the water with the evaporator to exchange heat with the refrigerant in the evaporator
Data Source
AI summary
A chiller system including an evaporator for evaporating a refrigerant and a water pipe in fluid communication with the evaporator. The water pipe is configured to allow water to pass through at a flow rate and to circulate the water with the evaporator to exchange heat with the refrigerant in the evaporator. The chiller system includes a flow restrictor tube within the water pipe that is configured to allow the water to flow through the flow restrictor tube at a reduced flow rate relative to the flow rate. The chiller system also includes a measuring probe that passes through walls of the water pipe and the flow restrictor tube and includes an accuracy range of flow rates less than the flow rate. The measuring probe is configured to measure the reduced flow rate within the flow restrictor tube where the reduced flow rate is within the accuracy range.