Definition
The electric thermostatic circulation tank is a commonly used equipment in laboratories, which maintains the liquid medium in the tank uniformly and stable at the set temperature through built-in heating elements and circulation pumps, and provides constant temperature liquid circulation for external systems. It is commonly used to provide a continuous and controlled temperature environment for reactors, detection instruments, or samples.
Principle
The equipment works on the principle of thermal equilibrium and fluid circulation. The heating element heats the medium in the tank, 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 maintains the temperature of the medium at the set value by adjusting the heating power. At the same time, the circulation pump pushes the medium to flow through the tank and the outer circulation pipeline, ensuring uniform temperature distribution. Its thermal equilibrium relationship can be expressed as:
QInput = Qloss + QAbsorb
Among them, QInputis the heating power, Qlossis the heat lost by the system to the environment, QAbsorbThe heat absorbed by the medium and the load.
Measurement method
Temperature measurements are usually measured using platinum resistors or thermocouple sensors and calibrated against relevant standards. The sensor should be placed in a typical position in the tank or in a circulation loop during measurement, and the reading should be recorded after the temperature has stabilized. For uniformity evaluation, multiple sensors can be placed in different positions in the tank to calculate the deviation between the temperature and the set value at each point. The circulating flow rate can be measured in the outlet line by the flow meter to ensure that the flow meets the application requirements.
Influencing factors
Temperature stability is influenced by various factors. Fluctuations in ambient temperature may lead to changes in heat dissipation conditions, affecting temperature control accuracy. Properties of the medium, such as specific heat capacity and viscosity, can change the heat transfer efficiency. The flow and pressure characteristics of the circulation pump are related to the temperature uniformity. In addition, changes in the heat capacity of the load, the insulation of the circulating lines, and the calibration status of the sensors can also affect actual performance.
Applications
The device functions in several areas. In chemical synthesis, it provides constant temperature conditions for the reactor; In material testing, it is used for sample environment simulation; In analytical instruments such as viscometers and refractometers, the sample temperature is maintained constant; In the electronics industry, it is possible to provide cooling or thermostatic cycling for test equipment. The basis for its application is to provide a reliable temperature environment for the process.
Selection considerations
A number of parameters need to be considered in the selection. The temperature range should cover the experimental requirements with some margin. The volume of the tank needs to adapt to the load size and the amount of media. The temperature control accuracy and uniformity should meet the allowable deviation of the experiment. The flow and pressure of the circulation pump need to match the resistance of the external system. Media compatibility requires tank and seal materials to withstand operating liquids. In terms of safety, it should have overheating protection and leakage protection functions. The power consumption and size of the equipment also need to be adapted to laboratory conditions.