Low-Temperature Concrete Testing Device with Insulated Indenter
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Solution Overview
Problem
Current low-temperature test devices for concrete are limited by large temperature drops, high costs, and risks associated with liquid nitrogen, as well as difficulties in disassembling and reusing heat insulation boxes, which affect the accuracy and convenience of mechanical property testing in low-temperature environments.
Innovation Solution
A test device comprising a universal testing machine, a cooling box made of double-layer stainless steel, a cold bath device with a freezing liquid mixture, a probe thermometer, and a stress-strain data acquisition instrument, where the cooling box is designed for easy assembly and disassembly, and the fiberglass reinforced plastic pipe cover provides heat insulation to maintain consistent low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid nitrogen is used for cooling, then the cooling speed and temperature range are improved, but the cost and safety risks increase
Solution Approach 1:
The patent changes the cooling medium from liquid nitrogen to a refrigeration system using refrigerants, fundamentally altering the temperature control parameters and eliminating the safety risks associated with liquid nitrogen while maintaining effective low-temperature testing capabilities
Solution Approach 2:
The patent replaces the mechanical liquid nitrogen cooling system with an electrical refrigeration system, substituting the mechanical approach with an electrical control system that offers better safety and temperature precision
2Temperature
If the heat insulation box is integrated with the loading device, then the temperature uniformity is improved, but the ease of operation deteriorates
Solution Approach 1:
The patent divides the integrated system into separate modules: the heat insulation box and the universal testing machine are independent components that can be separately assembled and disassembled, allowing the heat insulation box to maintain temperature uniformity while the separate mounting of the testing machine preserves operational convenience
3Device complexity
If the indenter and press are not protected by heat insulation, then the device complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
The patent applies heat insulation specifically to the indenter and press components that require it, rather than insulating the entire system. This localized approach maintains testing accuracy where needed while avoiding unnecessary complexity in other areas
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 device accurately controls and reuses low temperatures, improves the utilization rate of universal testing machines, ensures high accuracy in testing mechanical properties of concrete, and is cost-effective and easy to operate, allowing for comprehensive testing of concrete under various low-temperature conditions.
Implementation Method 1
The cold bath device and the interlayer cavity are provided with a freezing liquid; an outlet of the cold bath device communicates with the liquid inlet of the cooling box through a liquid inlet tube; an inlet of the cold bath device communicates with the liquid outlet of the cooling box through a liquid outlet tube
Implementation Method 2
four walls of the cooling box are provided with a heat insulation plate; both the top of the press and the bottom of the indenter are provided with a fiberglass reinforced plastic pipe cover
Data Source
AI summary
The invention provides a test device and method for controlling a low-temperature environment. A double-layer stainless steel plate forms an interlayer cavity of a cooling box; four walls of the cooling box are provided with a heat insulation plate; a probe thermometer is disposed on a side wall of the cooling box; both the top of a press and the bottom of an indenter of a universal testing machine are provided with a fiberglass reinforced plastic pipe cover; the cooling box is disposed on the press; the indenter is disposed in the cooling box through a through hole; a cold bath device communicate with the cooling box; the cold bath device and the interlayer cavity are provided with a freezing liquid; a stress-strain data acquisition instrument is connected to a sample in the cooling box through a strain gage and a strain gage connection line.