Tumor sample micro-weighing thermostat holder

Abstract

The utility model discloses a kind of tumour sample trace weighing constant-temperature bracket, belong to biological experimental apparatus technical field.It aims to solve the problem of big tumour sample weighing error caused by no temperature control or uneven temperature control of traditional weighing bracket.The bracket includes bearing unit, heating unit and temperature control unit, and bearing unit is polytetrafluoroethylene tray;Heating unit contains 1050W heating sheet distributed in honeycomb matrix, so that the standard deviation of temperature distribution on the upper surface of bearing unit is less than 2℃;In temperature control unit, platinum resistance temperature sensor collects temperature signal, which is transmitted to PID temperature control circuit after being processed by platinum resistance signal conditioning circuit, and PID temperature control circuit generates control signal to adjust heating sheet work through heating sheet driving circuit, to realize 30-40℃±1℃ accurate temperature control.It also includes LCD display, audible and visual alarm and overcurrent protection unit.The utility model can avoid weighing error caused by temperature fluctuation, improve experimental data accuracy, and has high usability and safety.

Description

Technical Field

[0001] This utility model relates to the field of biological experimental equipment technology, and in particular to a constant temperature support for micro-weighing of mouse tumor samples. Background Technology

[0002] In mouse tumor experiments, the weight measurement of tumor samples is a key step in evaluating experimental data such as drug efficacy and tumor growth status. The tumor sample weighing rack is a core auxiliary device that works with the balance to complete this measurement process. Its main function is to provide a stable support platform for the isolated tumor sample, ensuring that the sample is fixed in position and subjected to uniform force during the weighing process, and reducing weighing deviations caused by mechanical factors.

[0003] Existing tumor sample weighing racks have a simple structure, typically consisting of only a support tray made of metal or ordinary plastic, providing only basic load-bearing function and lacking any temperature control components. This traditional rack has significant drawbacks: after the tumor sample is removed from the body, fluctuations in ambient temperature can cause moisture evaporation or changes in metabolic activity, leading to weighing errors of up to 5%-10%, severely impacting the accuracy of subsequent drug dosage calculations and experimental data. Even some improved racks that attempt to regulate temperature through single-point heating lack uniform heating design, resulting in uneven temperature distribution and large temperature differences on the tray surface, failing to provide a stable constant temperature environment for the sample and still falling short of meeting the temperature sensitivity requirements of biological samples. Utility Model Content

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a constant temperature support for micro-weighing of tumor samples, comprising a support unit, a heating unit and a temperature control unit.

[0005] The support unit is a PTFE tray with a thermal conductivity of 0.25 W / (m·K), used to hold mouse tumor samples weighing <1g. The heating unit is fixedly mounted on the lower surface of the support unit and includes a 1050W low-power embedded heating element arranged in a honeycomb matrix. The density of the honeycomb matrix ensures that the standard deviation of the temperature distribution on the upper surface of the support unit is <2℃. The temperature control unit includes a temperature sensing module, a signal processing module, a control module, and a drive module. The temperature sensing module is a platinum resistance temperature sensor embedded in the upper surface of the support unit, located at the center and periphery of the sample placement area, used to acquire the temperature signal of the upper surface of the support unit in real time. The signal processing module is a platinum resistance signal conditioning circuit, including a Wheatstone bridge circuit and a low-pass filter. The input terminals of the wavelet circuit and the Wheatstone bridge circuit are electrically connected to the platinum resistance temperature sensor to convert the sensor's resistance change into a voltage signal. The input terminal of the low-pass filter circuit is electrically connected to the output terminal of the Wheatstone bridge circuit to filter the voltage signal. The control module is a PID temperature control circuit, whose input terminal is electrically connected to the output terminal of the low-pass filter circuit. It receives the filtered temperature signal and generates a control signal according to the preset temperature control range of 30-40℃. The temperature control accuracy of the PID temperature control circuit is ±1℃. The drive module is a heating element drive circuit, including a MOSFET switch circuit. The input terminal of the MOSFET switch circuit is electrically connected to the output terminal of the PID temperature control circuit, and the output terminal is electrically connected to the heating element of the heating unit. It is used to adjust the working state of the heating element according to the control signal.

[0006] Furthermore, the honeycomb matrix is ​​a regular hexagonal honeycomb structure, with 12-20 heating elements, each with equal power, and the center-to-center distance between adjacent heating elements is 5-8 mm.

[0007] Furthermore, the number of platinum resistance temperature sensors is 3-5, and they are evenly distributed in a ring along the center of the upper surface of the support unit, with a spacing of 10-15mm between adjacent sensors.

[0008] Furthermore, the PID temperature control circuit also includes a microcontroller sub-circuit and a digital-to-analog converter sub-circuit. The input terminal of the microcontroller sub-circuit is electrically connected to the output terminal of the low-pass filter sub-circuit, and the output terminal is electrically connected to the input terminal of the MOSFET switch sub-circuit via the digital-to-analog converter sub-circuit, which is used to realize PID algorithm adjustment through a preset program.

[0009] Furthermore, it also includes a display unit, which is an LCD temperature display screen. The LCD temperature display screen is electrically connected to the PID temperature control circuit through an I2C communication circuit and is used to display the temperature value of the upper surface of the carrier unit in real time.

[0010] Furthermore, it also includes an alarm unit, which is an audible and visual alarm circuit. The input terminal of the audible and visual alarm circuit is electrically connected to the PID temperature control circuit. When the temperature on the upper surface of the bearing unit exceeds the range of 30-40℃, the PID temperature control circuit triggers the audible and visual alarm circuit to work.

[0011] Furthermore, the heating element driving circuit also includes an overcurrent protection sub-circuit, which is connected in series between the MOSFET switching sub-circuit and the heating element, and is used to cut off the circuit when the operating current of the heating element exceeds a preset threshold.

[0012] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages compared with the prior art: A. This utility model achieves constant temperature control of the weighing environment for tumor samples by setting up a heating unit and a temperature control unit, effectively avoiding sample moisture evaporation or changes in metabolic activity caused by temperature fluctuations, significantly reducing weighing errors and improving the accuracy of experimental data; B. The heating unit adopts a honeycomb matrix distribution of heating elements, combined with a polytetrafluoroethylene (PTFE) support unit, which ensures uniform temperature distribution on the upper surface of the support unit and a temperature distribution standard deviation of <2℃, thus solving the problem of large temperature difference in traditional single-point heating methods. C. The temperature control unit uses a platinum resistance temperature sensor and a PID temperature control circuit to achieve precise temperature control within ±1℃ in the range of 30-40℃, meeting the requirements of biological samples for a constant temperature environment; D. The addition of a display unit, alarm unit, and overcurrent protection sub-circuit improves the ease of use and safety of the device, making it easier for experimental personnel to monitor the temperature status in real time and handle abnormal situations promptly.

[0013] Other advantages, objectives and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be taught from the practice of this invention. Attached Figure Description

[0014] Figure 1 This is a three-dimensional schematic diagram of the constant temperature support for micro-weighing of tumor samples according to the present invention; Figure 2 This is a longitudinal cross-sectional schematic diagram of the thermostatically controlled tray for micro-weighing of tumor samples according to this utility model. Figure 3 This is a structural diagram of the thermostatically controlled weighing rack for tumor samples of this utility model. Figure 4 This is a circuit diagram of the thermostatically controlled tray for micro-weighing of tumor samples according to this utility model.

[0015] As shown in the figure: 1. Bearing unit; 2. Heating unit; 3. Temperature control unit; 4. Platinum resistance temperature sensor; 5. Control module; 6. MOS transistor switching circuit. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] It should be noted that the terms "vertical," "horizontal," "up," "down," "left," "right," and similar expressions used in this article are for illustrative purposes only and do not represent the only possible implementation.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0019] like Figure 1-4As shown, a constant temperature support for micro-weighing of tumor samples includes a support unit 1, a heating unit 2, and a temperature control unit 3. The support unit 1 is a tray made of polytetrafluoroethylene (PTFE) with a thermal conductivity of 0.25 W / (m·K), used to hold mouse tumor samples weighing <1g. The heating unit 2 is fixed to the lower surface of the support unit 1 and uses 1050W low-power embedded heating elements. The heating elements are arranged in a regular hexagonal honeycomb matrix, with 15 elements of equal power. The center-to-center distance between adjacent heating elements is 6mm, ensuring that the standard deviation of the temperature distribution on the upper surface of the support unit 1 is <2℃. The temperature control unit 3 includes platinum resistance temperature sensors 4, a platinum resistance signal conditioning circuit, a PID temperature control circuit (control module 5), and a heating element drive circuit. Four platinum resistance temperature sensors 4 are embedded in the upper surface of the support unit 1, evenly distributed in a ring along the center of the upper surface of the support unit 1, with a spacing of 12mm between adjacent sensors, for real-time acquisition of temperature signals. The platinum resistance signal conditioning circuit includes a Wheatstone bridge circuit and a low-pass filter sub-circuit. The Wheatstone bridge circuit is electrically connected to the platinum resistance temperature sensors 4, converting the resistance change into a voltage signal, and the low-pass filter... The wavelet circuit filters the voltage signal; the PID temperature control circuit includes a microcontroller sub-circuit and a digital-to-analog converter sub-circuit, whose input is electrically connected to the output of the low-pass filter sub-circuit, receives the filtered temperature signal, and adjusts it according to the preset temperature control range of 30-40℃ through a preset program using the PID algorithm to generate a control signal, with a temperature control accuracy of ±1℃; the heating element drive circuit includes a MOSFET switch sub-circuit 6 and an overcurrent protection sub-circuit, the input of the MOSFET switch sub-circuit 6 is electrically connected to the output of the PID temperature control circuit, and the output is electrically connected to the heating element of the heating unit 2 through the overcurrent protection sub-circuit, adjusting the working state of the heating element according to the control signal, and the overcurrent protection sub-circuit cuts off the circuit when the working current of the heating element exceeds a preset threshold; the device also includes an LCD temperature display screen and an audible and visual alarm circuit, the LCD temperature display screen is electrically connected to the PID temperature control circuit through an I2C communication circuit to display the temperature value in real time, and the audible and visual alarm circuit is electrically connected to the PID temperature control circuit, triggering operation when the temperature exceeds the 30-40℃ range.

[0020] During operation, mouse tumor samples are placed on the support unit 1. The platinum resistance temperature sensor 4 collects the temperature signal of the upper surface of the support unit 1 in real time. After conversion and filtering by the platinum resistance signal conditioning circuit, the signal is transmitted to the PID temperature control circuit. The PID temperature control circuit generates a control signal according to the preset temperature range, which controls the heating element of the heating unit 2 through the heating element drive circuit, thereby achieving precise control of the temperature of the upper surface of the support unit 1. The LCD temperature display shows the temperature in real time, the audible and visual alarm circuit alarms when the temperature is abnormal, and the overcurrent protection subcircuit ensures the safe operation of the device. During installation, the lower surface of the support unit is attached to the weighing platform of the 1 / 10,000 precision balance using a 1mm thick silicone anti-slip pad. The edge of the silicone anti-slip pad is flush with the edge of the support unit and is secured with double-sided tape to prevent the device from sliding during weighing. The honeycomb heating element of the heating unit is adhered to the lower surface of the support unit using high-temperature resistant silicone rubber adhesive, with the adhesive thickness controlled within 0.5mm to ensure tight contact between the heating element and the support unit. The circuit board of the temperature control unit is fixed to the metal casing with four M3 screws. The top of the casing is separated from the lower surface of the heating unit by heat insulation cotton with a thickness of 3mm. The sides of the casing have 5mm diameter ventilation holes spaced 20mm apart. Rubber feet are installed at the bottom, with the height of the feet adapted to the distance from the weighing platform of the balance to the table.

[0021] Before use, the balance with an accuracy of 0.01% needs to be preheated for at least 30 minutes. After the balance display stabilizes, complete the calibration using standard weights through its calibration procedure. Then, place the device in the center of the balance weighing platform, ensuring that the silicone anti-slip pad is fully attached. Connect the device's power adapter, which has an output voltage of 12V, and plug it into a 220V AC power socket.

[0022] After the device is started, the LCD temperature display lights up, initially showing the ambient temperature. The target temperature can be set using the buttons on the side of the temperature control unit, and must be selected within the range of 30-40℃. After setting, the PID temperature control circuit automatically starts, and the platinum resistance temperature sensor begins to collect the temperature of the upper surface of the carrier unit. The signal is converted into a voltage signal by the Wheatstone bridge circuit. The Wheatstone bridge circuit uses three 100Ω standard resistors as reference arms, forming a four-arm bridge with the platinum resistance. The output voltage signal is processed by the low-pass filter sub-circuit, which is a second-order RC filter circuit with a resistance of 10kΩ, a capacitance of 0.1μF, and a cutoff frequency of approximately 16Hz. The signal after filtering out high-frequency interference is transmitted to the microcontroller sub-circuit. The microcontroller uses an STM32F103 chip, which calculates the control quantity through a preset PID algorithm. The digital-to-analog converter (using a DAC8552 chip) converts the signal into an analog signal, driving the MOSFET switching sub-circuit to work. The MOSFET used is an IRF540N, and the output power of the heating element is controlled by adjusting the duty cycle.

[0023] When the temperature displayed on the LCD temperature display differs from the target temperature by ≤±1℃, maintain this state for 5 minutes to confirm temperature stability. At this time, use tweezers to pick up the isolated mouse tumor sample (weight <1g) and place it in the center area of ​​the upper surface of the support unit, keeping the sample at least 2mm away from the platinum resistance temperature sensor. After placement, close the balance windproof cover, wait for the balance display value to stabilize, and record the weighing result. If the device temperature exceeds the range of 30-40℃ during the weighing process, the audible and visual alarm circuit will be automatically activated, the buzzer will sound continuously, and the red LED will flash. At this time, the weighing should be stopped, the temperature control unit should be checked for normal operation, and the temperature stabilization operation should be repeated after troubleshooting.

[0024] After use, first turn off the heating function by pressing the button. After the LCD temperature display shows that the temperature has dropped to room temperature, disconnect the power adapter, remove the device from the balance weighing platform, wipe the upper surface of the carrier unit with a 75% alcohol swab to remove sample residue, and store it in a dry and ventilated laboratory equipment cabinet.

[0025] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A thermostatically controlled tray for micro-weighing of tumor samples, characterized in that, include: The support unit (1) is a tray made of polytetrafluoroethylene, the thermal conductivity of which is 0.25W / (m•K), and is used to place mouse tumor samples weighing <1g. Heating unit (2) is fixedly disposed on the lower surface of the support unit (1). The heating unit (2) includes a 1050W low-power embedded heating element. The heating element is distributed in a honeycomb matrix, and the distribution density of the honeycomb matrix makes the temperature distribution standard deviation of the upper surface of the support unit (1) < 2℃. The temperature control unit (3) includes a temperature sensing module, a signal processing module, a control module (5), and a drive module; The temperature sensing module is a platinum resistance temperature sensor (4). The platinum resistance temperature sensor (4) is embedded in the upper surface of the support unit (1) and located in the center and periphery of the sample placement area. It is used to collect the temperature signal of the upper surface of the support unit (1) in real time. The signal processing module is a platinum resistance signal conditioning circuit. The platinum resistance signal conditioning circuit includes a Wheatstone bridge circuit and a low-pass filter circuit. The input terminal of the Wheatstone bridge circuit is electrically connected to the platinum resistance temperature sensor (4) and is used to convert the resistance change of the sensor into a voltage signal. The input terminal of the low-pass filter circuit is electrically connected to the output terminal of the Wheatstone bridge circuit and is used to filter the voltage signal. The control module (5) is a PID temperature control circuit. The input terminal of the PID temperature control circuit is electrically connected to the output terminal of the low-pass filter sub-circuit. It is used to receive the filtered temperature signal and generate a control signal according to the preset temperature control range of 30-40℃. The temperature control accuracy of the PID temperature control circuit is ±1℃. The driving module is a heating element driving circuit. The heating element driving circuit includes a MOS transistor switching sub-circuit (6). The input terminal of the MOS transistor switching sub-circuit (6) is electrically connected to the output terminal of the PID temperature control circuit, and the output terminal is electrically connected to the heating element of the heating unit (2). It is used to adjust the working state of the heating element according to the control signal.

2. The constant-temperature weighing rack for tumor samples according to claim 1, characterized in that, The honeycomb matrix is ​​a regular hexagonal honeycomb structure, the number of heating elements is 12-20, and the power of each heating element is equal, with a center-to-center distance of 5-8mm between adjacent heating elements.

3. The constant-temperature weighing rack for tumor samples according to claim 1, characterized in that, The number of platinum resistance temperature sensors (4) is 3-5, and they are evenly distributed in a ring along the center of the upper surface of the support unit (1), with a spacing of 10-15 mm between adjacent sensors.

4. The constant-temperature weighing rack for tumor samples according to claim 1, characterized in that, The PID temperature control circuit also includes a microcontroller sub-circuit and a digital-to-analog converter sub-circuit. The input terminal of the microcontroller sub-circuit is electrically connected to the output terminal of the low-pass filter sub-circuit, and the output terminal is electrically connected to the input terminal of the MOS transistor switch sub-circuit (6) via the digital-to-analog converter sub-circuit, which is used to implement PID algorithm adjustment through a preset program.

5. The constant-temperature weighing rack for tumor samples according to claim 1, characterized in that, It also includes a display unit, which is an LCD temperature display screen. The LCD temperature display screen is electrically connected to the PID temperature control circuit through an I2C communication circuit and is used to display the temperature value of the upper surface of the carrier unit (1) in real time.

6. The constant-temperature weighing rack for tumor samples according to claim 1, characterized in that, It also includes an alarm unit, which is an audible and visual alarm circuit. The input terminal of the audible and visual alarm circuit is electrically connected to the PID temperature control circuit. When the temperature of the upper surface of the bearing unit (1) exceeds the range of 30-40℃, the PID temperature control circuit triggers the audible and visual alarm circuit to work.

7. The constant-temperature weighing rack for tumor samples according to claim 1, characterized in that, The heating element driving circuit also includes an overcurrent protection sub-circuit, which is connected in series between the MOS transistor switching sub-circuit (6) and the heating element, and is used to cut off the circuit when the operating current of the heating element exceeds a preset threshold.

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