Overview
In order to meet the requirements of a constant temperature of 37°C and a miniaturized bioreaction system on the paper chip, we have made the following heating table.
Equipment Design and Processing
As shown in Figure 1, the heating table is mainly composed of four parts: a PT1000 thermal sensor; a silicone rubber heating film; a TCM1040 temperature control module, and structural housing. The PT1000 thermal sensor can collect the temperature of the silicone rubber heating film and give real-time feedback to the TCM1040 temperature control module. The silicone rubber heating film is connected to the TCM1040 temperature control module and outputs the appropriate temperature according to the preset parameters. The TCM1040 temperature control module is used to drive the silicone rubber heating film and adjust the heating state through feedback adjustment while receiving data collected by the sensor. The structural housing provides sufficient room to support the TCM1040 temperature control module, leaving a certain space to ensure the heat dissipation of the TCM1040 temperature control module, and the top platform is used to place the heating chamber.
A) PT1000 sensor;B) silicone rubber heating film;
C) TCM1040 small temperature control module; D) structural housing
The structural shell (Figure 2) contains the paper chip incubation chamber and the structure body, which is processed by 3D printing. The main body of the structure is made of resin as raw material to achieve the fixation of TCM1040, silicone rubber heating film, and PT1000 thermal sensor, and the paper chip incubation chamber is made of aluminum with a good thermal conductivity as raw material. There is a resin screw of size M3 on the top, and by adjusting the height of the screw, the cover part of the aluminum heating chamber can be pressed to make the paper chip in contact with the silicone rubber heating film more fully.
A) M3 screws; B) heating chamber cover; C) heating chamber body; D) the upper layer of the incubation apparatus; E) incubation device base; F) complete structure diagram
The control principle of the heating table (Figure 3) is as follows: the user provides a 5V power supply to the TCM1040 small temperature control module, presets the parameters of the temperature control module through the host computer, and after entering the working state, the TCM1040 temperature control module controls the heating of the silicone rubber, the PT1000 heat sensor collects the heating film’s temperature data and feeds the data back to the TCM1040 temperature control module, and the system maintains a constant temperature when it reaches 37℃ through feedback regulation.
Experimental Test Section
After the equipment is set up, the heating film’s temperature is monitored in real-time with the thermometer and the temperature data collected by the sensor is compared. The error is about 0.1℃, which is a reasonable range. After that, the data is collated and a period of data with a constant temperature is selected for processing, and the processing result is as follows (Figure 4). By exporting the temperature change per second to produce a curve, it can be seen from the image that our incubation device can be heated at a uniform speed, eventually stabilizing to about 37℃.
Uniformity Test
We randomly extracted six positions of the silicone rubber heating film and used the Fluke 51II thermometer temperature test on the six positions, the temperature of the six positions is similar to the sensor indication, and the temperature between the six positions is basically the same (Figure 5, Figure 6) Therefore, it can be considered that heating uniformity of the silicone rubber heating film is achieved.
Accuracy Testing
When the temperature reaches 37℃, the temperature is recorded every 10 seconds for 60 seconds, and the difference between the average value and the set temperature should be no more than 0.1℃ in absolute terms (Figure 7). Therefore, it can be considered that the incubation device has good temperature control accuracy.
Module Temperature Control Accuracy Test
When the heating is completed and enters the constant temperature state, the temperature can be maintained at about 37℃ for a long time under the condition of uninterrupted electricity. The maximum and minimum temperatures can be recorded, with half the difference between them within the preset range of 0.2℃ (as shown in Figure 8), thus the incubation device can be considered to have good temperature control accuracy.
