Low-Restriction Thermistor Flow Path for Pump Temperature Sensing
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Solution Overview
Problem
Conventional fluid pumps lack effective temperature sensing mechanisms that provide real-time and accurate temperature measurements of the fluid, especially when submerged, due to limited fluid movement and potential interference from motor heat.
Innovation Solution
Incorporating an accessory fluid path with a low-restriction return path and a thermistor positioned to monitor the temperature of the excess fluid flow, ensuring it maintains a similar temperature to the primary flow, allowing real-time temperature monitoring without performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermistor is positioned to monitor fluid temperature in a conventional pump, then temperature measurement capability is provided, but the motor heat interferes with the accuracy of temperature measurements
Solution Approach 1:
The fluid path is segmented into a primary flow path for main fluid transport and an accessory flow path for temperature sensing. The accessory flow path is positioned to bypass the motor housing, separating the temperature measurement function from the heat-generating motor components while still monitoring fluid temperature accurately.
Solution Approach 2:
An accessory fluid path acts as an intermediary channel that allows thermistor placement in a location shielded from motor heat. This intermediary path carries fluid between the inlet and outlet while passing through a region where temperature measurements can be taken without direct motor heat interference.
2Measurement precision
If an accessory fluid path is added for temperature monitoring, then real-time temperature measurement is enabled, but the device complexity increases
Solution Approach 1:
The accessory fluid path serves multiple functions: it provides a route for temperature sensing, ensures continuous fluid flow for accurate thermistor readings, and positions the sensing region away from motor heat. This multi-functional design achieves temperature monitoring without proportionally increasing complexity.
Solution Approach 2:
The accessory flow path is integrated with the existing pump structure, sharing the inlet and outlet connections with the primary flow path. The thermistor is incorporated into the circuit board housing, merging the sensing element with the existing housing structure rather than adding a separate assembly.
3Ease of operation
If the thermistor is positioned near the motor, then the temperature measurement is easily accessible, but the measurement reflects motor heat rather than fluid temperature
Solution Approach 1:
The accessory fluid path creates a localized measurement region with distinct thermal characteristics from the motor housing. The fluid in this path maintains a temperature representative of the bulk fluid rather than the elevated temperature near the motor, providing locally accurate temperature measurements.
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
Provides accurate and real-time temperature measurements of the fluid within the fluid pump, maintaining fluid temperature consistency and enhancing pump performance by minimizing heat interference from the motor.
Implementation Method 1
A thermistor is positioned in communication with the contoured portion to simultaneously monitor, in real time, the temperature of the excess flow of the fluid in the accessory fluid path and the temperature of the primary flow of the fluid in the fluid path
Implementation Method 2
The low-restriction return path is configured to maintain a temperature of the continuous flow of the fluid within the contoured portion of the accessory fluid path to be similar to a temperature of the primary flow of the fluid
Data Source
AI summary
A fluid pump includes a pump element where rotation of the pump element generates suction at the inlet and pressure at the outlet to move fluid through a fluid path. An inlet orifice directs a portion of the fluid through the accessory fluid path that includes a low-restriction return path providing a continuous flow of the fluid through the accessory fluid path and to an outlet orifice. A circuit board housing includes a contoured portion and a PCB with a thermistor in communication with contoured portion. The continuous flow is directed between the contoured portion and the outlet orifice between a rotor and the outer wall. The low-restriction return path maintains a temperature of the continuous flow of the fluid within the contoured portion of the accessory fluid path to be similar to a temperature of the fluid in the fluid path.