Definition
Cryogenic thermostatic tank is a kind of laboratory equipment that establishes and maintains a stable low-temperature environment in the tank through a refrigeration and heating system. It is typically used to provide precise temperature control conditions for external experimental setups or samples placed directly in the tank, typically ranging from minus tens of degrees Celsius to near ambient temperatures.
How it works:
The core working principle of the cryostatic chamber is based on thermodynamic equilibrium and closed-loop control. The equipment is mainly composed of tank, refrigeration unit, heating unit, circulation pump, temperature sensor and control system. The refrigeration unit mostly uses compressor cooling or thermoelectric refrigeration technology to remove heat; The heating unit replenishes the heat with an electric heating element. The temperature sensor monitors the temperature of the medium in the tank in real time and feeds the signal back to the control system. The control system dynamically adjusts the cooling and heating power according to the deviation between the set temperature and the measured temperature, and the circulation pump promotes the uniform flow of liquid medium in the tank, so as to achieve rapid stability and uniform distribution of temperature.
Measurement method
The performance evaluation of cryogenic chambers is usually carried out according to relevant national or international standards, and the main measurement parameters include temperature stability, uniformity and setting accuracy. Temperature stability refers to the amplitude of temperature change in a certain point in the trough with time at a set temperature; Uniformity refers to the temperature difference at different spatial points in the groove at the same time. During the measurement, multiple calibrated high-precision platinum resistance thermometers are placed in different positions in the working area of the tank, and the temperature changes are recorded by the data collector. The accuracy of the temperature setting is verified by comparing the displayed values of the device with the measured values of a standard thermometer. The typical calculation formula is as follows:
Temperature stability = Tmax - Tmin
where Tmaxand TminIt is the maximum and minimum values of the temperature at a certain point during the measurement period.
Influencing factors
The performance of a cryogenic thermostatic tank is affected by a variety of factors. Environmental conditions such as laboratory ambient temperature and humidity fluctuations may increase the load on the refrigeration system and affect the temperature control accuracy. The properties of the medium in the tank, including specific heat capacity, viscosity and thermal conductivity, are directly related to the temperature transfer efficiency and uniformity. Inadequate insulation of equipment can lead to heat loss. In addition, the flow and pressure characteristics of the circulation pump will affect the uniformity of the medium flow. The calibration status of the sensor and the response speed of the control algorithm are also key factors in determining long-term stability. The heat capacity and placement of the sample load can also introduce temperature disturbances when operated by the user.
Applications:
Cryogenic chambers are widely used in experiments and testing processes that require low-temperature and constant temperature environments. In materials research, it is used for low-temperature performance testing of polymer materials or metal materials; In the chemical field, provide low-temperature cooling sources for reactors or distillation plants; In the electronics industry, it is used for low-temperature aging tests of semiconductor components or circuit boards; In food science, assist in completing cryopreservation or viscosity determination of samples; In the field of metrology, it serves as a low-temperature environmental source for temperature sensor calibration. Its ability to provide a stable low-temperature environment supports R&D and quality control activities in many industries.
Key points of selection
When choosing a low-temperature constant temperature tank, it is necessary to comprehensively consider the technical parameters and experimental needs. First, the required temperature range, control accuracy and stability indicators should be clarified. The tank volume and opening size should be adapted to the size of the sample or external device. Pay attention to the compatibility of the medium in the tank, and choose a liquid with a suitable viscosity and freezing point according to the operating temperature, such as silicone oil or ethanol solution. Cooling capacity needs to meet the time required to drop from high to target temperature, taking into account the ability to maintain under maximum thermal load. Safety features of the equipment, such as level protection, over-temperature alarms, and electrical safety certifications, should also be evaluated. In addition, practical usage factors such as energy consumption, operating noise, and maintenance convenience are also recommended to be comprehensively considered.