Dental Syringe Fluid Heating with Microprocessor Temperature Control
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Solution Overview
Problem
Existing dental syringe heating devices often result in a transitory period of cold fluid supply due to the activation of heating elements only when the supply buttons are pressed, leading to inefficient temperature control and potential overheating, especially with resistances or PTC heating elements.
Innovation Solution
The use of two MOSFET transistors controlled by sensors and a microprocessor to simulate a resistive behavior, ensuring continuous fluid heating and precise temperature control, eliminating the need for additional electronic components and allowing for immediate warm fluid supply without requiring a specific flow rate or button actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If heating elements (resistance or PTC) are actuated only when the supply button is pressed, then the device complexity is reduced and manufacturing cost is lowered, but the temperature control precision deteriorates and transitory cold fluid supply occurs
Solution Approach 1:
The heating elements are activated in advance by a microswitch before the fluid supply button is pressed, ensuring that the fluid reaches the desired temperature before delivery begins. This preliminary heating action eliminates the transitory cold fluid supply problem while maintaining simple device construction.
Solution Approach 2:
A temperature sensor provides feedback to the control circuit, which regulates the heating elements based on the actual fluid temperature. This feedback mechanism ensures precise temperature control while avoiding overheating, resolving the contradiction between simple construction and temperature precision.
2Extent of automation
If PTC self-regulating resistances are used for heating, then the temperature control is automated, but the temperature control precision deteriorates and excessive heating may occur
Solution Approach 1:
A thermocouple or temperature sensor acts as an intermediary between the PTC heating element and the control circuit, providing precise temperature feedback that enables accurate temperature regulation without excessive heating, while maintaining the automated control benefit of PTC elements.
3Measurement precision
If a temperature control system with MOSFET transistor or TRIAC is implemented, then the temperature control precision is improved, but the device complexity increases
Solution Approach 1:
The complex MOSFET or TRIAC-based temperature control system is extracted and replaced with a simpler microswitch-actuated heating system that achieves adequate temperature control through preliminary heating and basic feedback, reducing device complexity while maintaining sufficient temperature precision for dental applications.
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 ensures that warm air and water are supplied immediately and consistently maintained at a predetermined temperature, even during small flow rates, while simplifying the device construction and reducing the risk of overheating or temperature fluctuations.
Implementation Method 1
two MOSFET transistors opportunely controlled so as to simulate a resistive behaviour
Implementation Method 2
Suitable sensors, located in strategic positions and afferent to a microprocessor, control fluid temperature
Implementation Method 3
control fluid temperature, so as to avoid both overheating and excessive lowering of the temperature itself
Data Source
Figure 1
Figure 2~2B
Figure 3~4
AI summary
Dental syringe (1) comprising: a supply cord (2) connecting it to a dental unit, a housing (3), a nozzle (4), a couple of valves supplying and stopping water and air, and heating elements (20, 26) for the supplied fluids, switchable on by a ring nut (10), wherein the heating systems are contained inside housing (3) and comprising means (21, 22, 27, 28, 29) for fluids temperature control, capable of keeping said fluids warm even when syringe (1) is at rest, and in that the water heating system comprises a heat exchanger (13) and at least a heating element (20), a temperature sensor (21) at the heat exchanger, a temperature sensor (22) at the exit from the heat exchanger (13), and a microprocessor (29).