Definition
A transparent thermostatic tank is an experimental device that maintains a constant temperature of the liquid medium in the tank through a heating and circulation system, and intuitively observes the internal samples or processes with the help of the transparent tank. Its core function is to provide a stable, uniform, and visible temperature environment, which is widely used in materials, chemicals, biology, food, and other fields for sample constant temperature processing, reaction observation, and physical property testing.
Principle
Transparent thermostatic sinks work on the principle of thermal balance and fluid circulation. The system typically consists of a heating unit, temperature sensor, circulation pump, and transparent tank. The heating unit heats the liquid medium, and the temperature sensor monitors the temperature of the medium in real time and feeds the signal back to the control system. The control system regulates the heating power through a proportional-integral-differential algorithm to maintain the set temperature. The circulation pump promotes the flow of media in the tank and in the external circulation pipeline, ensuring uniform temperature distribution. Transparent tanks are typically made of glass or polymer materials, allowing users to directly observe the internal experimental process.
The temperature control process can be simplified to a closed-loop feedback model: set temperature Tsetand the actual temperature TactualThe deviation of e(t) = Tset-Tactual, the controller calculates the output control signal u(t), and drives the heater to adjust the heat input Q(t) to make the system balanced. The dynamic relationship can be expressed as: Q(t)=Kp·e(t)+Ki∫e(t)dt+Kd·de(t)/dt, where Kp、Ki、Kdis the control parameter.
Measurement method
The performance evaluation of thermostatic sinks typically involves measurements of temperature stability, uniformity, and accuracy. Temperature stability refers to the amplitude of temperature fluctuations in a certain point in the trough with time at a set temperature, which can be continuously monitored by a high-precision temperature recorder. Temperature uniformity refers to the temperature difference at different spatial points in the tank in the steady state, and multiple temperature measurement probes need to be arranged in the working area of the tank during measurement. Accuracy refers to the long-term consistency between the actual temperature and the set temperature, which needs to be calibrated with reference to a standard thermometer. The measurement process should follow relevant standards, such as ensuring sensor calibration, avoiding external thermal interference, and ensuring adequate circulation of the medium.
Influencing factors
The performance of a clear thermostatic sink is influenced by several factors. Fluctuations in ambient temperature may lead to heat loss or accumulation, affecting temperature control stability. The balance between the heat conduction characteristics and transparency of the tank material is related to the observation clarity and thermal insulation effect. The flow rate and flow direction design of the circulation pump directly affect the temperature uniformity, and insufficient flow may cause temperature stratification. The matching degree between the heating power and the controller parameters determines the response speed and overshoot of temperature regulation. The properties of the medium, such as specific heat capacity, viscosity, and transparency, will also affect the heat transfer efficiency and observation effect. In addition, the size, material, and placement of the load in the tank may disturb the temperature field distribution.
Applications
In materials science, transparent thermostatic sinks are used for phase transition observation of polymer materials and monitoring of the curing process of composite materials. It is often used in the field of chemical engineering to simulate catalytic reaction conditions and study the crystallization process of solutions. It is used in the food industry for oil melting point determination and beverage stability testing. In terms of environmental detection, it can be used for the cultivation of water quality biological samples and the observation of sediment interface reactions. Its transparent characteristics enable the visualization of dynamic processes and facilitate the study of process mechanisms. In some standard methods, such as viscometer calibration, heat shrinkage test, transparent thermostatic sink is also a common auxiliary equipment.
Key points of selection
Technical parameters and experimental requirements should be comprehensively considered when selecting. The temperature range should cover the required range of the experiment with a certain margin. The tank volume needs to match the sample size and quantity, while considering the economy of media usage. The temperature stability and uniformity indexes should meet the requirements of experimental accuracy, and the general stability can be within ±0.1°C and the uniformity is within ±0.5°C. The circulation mode is divided into internal circulation and external circulation, the internal circulation is suitable for uniform temperature control in the tank, and the external circulation can be connected to external equipment. The material of the tank should take into account transparency, temperature resistance and chemical compatibility, and common borosilicate glass, polycarbonate, etc. Control system functions such as program heating, multi-point temperature recording, communication interface, etc., can be selected according to automation needs. Safety features such as overheating protection and low level alarms also need to be taken into account.