The “Xinyi” constant temperature bath is suitable for the constant temperature environment of the main part of the petroleum liquefied gas density meter. The working area is large, the size is Φ260×420 , and the mixing area size is Φ160×420 , the total volume is 34 liters, and other properties are : Its working temperature range is 10 °C ~ 95 °C , the ambient temperature should be lower than 30 °C , the total power is 3KW , the power supply is 220V/50HZ , so it can work in the general laboratory. Its working principle is shown in Figure 1.

Thermostat working principle diagram

In order to ensure the temperature stability and uniformity of the medium in the working area, we choose the tank structure scheme of lateral agitation. The following describes the working principle of the bath according to the flow of the working medium in the tank: under the stirring ( 4 ), the working medium is The mixing zone ( 2 ) flows from top to bottom, and is first exchanged by the coil evaporator ( 1 ) and the heater ( 3 ) to make the flowing medium reach a certain temperature, and then the agitator is used to strongly agitate the temperature. The less uniform medium is thoroughly mixed, which in turn pushes the medium out of the bottom, and the flow is directed upward into the working area ( 6 ), and the medium has a certain flow rate. In the process of flowing through the working area, the medium is required to minimize the heat exchange with the outside world, so as to ensure the uniform temperature of the working medium and create favorable conditions for high-quality temperature control. Thereafter, the medium flows into the mixing area and repeats in turn. The circulation of the flow. The temperature sensing element ( 5 ) of the temperature control system is placed in the fluid for measuring the temperature signal, and the temperature control system adjusts the output pulse signal according to the temperature change measured by the temperature sensing element, and finally drives the two-way thyristor to push the heater. Heating to control the bath temperature to work at the set temperature.

When the bath temperature is close to or lower than room temperature, the constant temperature bath refrigeration system is put into operation, and the cooling medium is cooled by the coil evaporator ( 1 ) installed in the tank body to achieve cooling. In order to increase the cooling rate of the medium, the cooling capacity can be adjusted in two stages. When the temperature is lowered, the refrigerator can work under the condition of high evaporation temperature and large load. When working near the constant temperature or lower limit temperature, the refrigerator is operated under the conditions of low evaporation temperature and low load, which is also beneficial to temperature stability. The content of this article comes from http:// Xinyi Instrument Network http://

At constant temperature, the cooling and heating components in the bath simultaneously operate. The cooling device primarily provides cooling for cooling and ultimately maintaining the required low temperature, while the heater is used to provide balanced heat for temperature control.

2 , refrigeration system:   

The refrigeration system of the device adopts a single-stage vapor compression refrigeration cycle system, the refrigerant is R22 , and the compressor is discharged into high-temperature and high-pressure superheated steam by air-cooling condensation method, and is condensed into a high-pressure liquid, which becomes a low-pressure wet steam through a filter and a throttling device. To the evaporation coil in the tank, at the same time, after sucking the heat in the working medium (soft water) in the tank, it becomes a low-pressure superheated steam, and finally is sucked into the compressor to be compressed and discharged, so that the circulation continuously completes the heat absorption to the working medium. Cool down. The content of this article comes from http:// Xinyi Instrument Network http://

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  3 , temperature control system:   

The liquid thermostat requires that the temperature in the controlled zone is stable and the distribution is very uniform. On the one hand, it is determined by the structural design of the thermostatic bath, which involves the structure, installation position and thermal inertia of the temperature sensing element, heater and evaporator. And the uniformity of the medium is heated, the insulation of the device, the quality of the insulation and the stability of the whole machine are stable and reliable. When the bath structure is determined, another determining factor is the temperature control system.