Shanghai Sairui Electrical Maintenance Co., Ltd.

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The company's main business: compressor maintenance, refrigeration equipment maintenance, ultra-low temperature equipment maintenance Shanghai Sairui Refrigeration Equipment Co., Ltd. specializes in repairing screw compressors and providing screw refrigeration compressors. Maintenance, maintenance and overhaul of central air-conditioning and industrial refrigeration equipment hosts of world-renowned brands such as York, Trane, Carrier, Dunham Bush, Maxwell, Hitachi, Daikin, Grasso, and central air-conditioning compressor repair
&The refrigeration system of the ultra-low temperature refrigerator basically adopts the working principle of cascade refrigeration, and uses two fully enclosed compressors as high and low temperature stage compressors. The copper tube of the low-temperature evaporator is directly attached to the outside of the inner box in the form of a coil, and the gap between the coil and the box wall is filled with thermal conductive cement to increase the heat exchange effect. The condensing evaporator has a shell-and-tube structure, with four-tube threaded copper tubes inside, and uses a counter-flow heat exchange method.
The low-temperature system is also equipped with a gas heat exchanger, which allows the low-pressure gas coming out of the evaporator to exchange heat with the high-pressure gas before entering the condensing evaporator. This not only reduces the heat load of the condensing evaporator, but also Make full use of the heat. Most filters use wax-removing filters, whose purpose is to effectively remove paraffin in the refrigeration oil to reduce the possibility of "oil clogging" in the system.
Ultra-low temperature refrigerators generally have two types of boxes: horizontal and vertical. The inner box is generally divided into multiple load-bearing layers, and each layer is designed with an inner door that can be opened and closed independently. The outer box is generally made of five cold-rolled steel plates directly spliced to each other. The inside and outside of the box are made of polyurethane foam. The thermostat is a platinum resistance sensor used for precise temperature control. Refrigerants are now generally environmentally friendly refrigerants to meet environmental protection requirements.
In addition, the ultra-low temperature refrigerator can also be equipped with some accessories according to different uses, such as a temperature recorder to facilitate permanent recording of operating parameters. A carbon dioxide backup system is used under special circumstances to ensure that the gas in the storage environment remains in a normal state and the voltage increases. The compressor can ensure the normal operation of the compressor under low pressure.
& Ultra-low temperature refrigerators generally use two-stage refrigeration. The refrigerant in the first stage is R (.,), the design pressure is high pressure (=&) and low pressure. The condenser of the second stage refrigeration and the evaporator of the first stage refrigeration are put together. The refrigerant of the second stage is a mixture of R (.) and R (.), and the designed high and low pressures are both. The temperature probe is a thermistor, which displays different temperatures on the panel according to the resistance value (that is, the temperature).
When the power is turned on, when the temperature displayed on the panel is higher than the set temperature, the first-stage compressor starts first, and the first-stage refrigeration system starts to work, causing the condenser temperature of the second-stage refrigeration system to drop, that is, The temperature of the second-stage refrigerant drops. After a delay of a few minutes, the second-stage refrigeration system also starts to work. Its evaporator is on the inner wall of the refrigerator, which can make the internal temperature of the refrigerator drop a lot. The heat released by its condenser All is absorbed by the evaporator of the first-stage refrigeration system, and the heat released by the first-stage condenser is dissipated into the air.
When the internal temperature of the refrigerator reaches the set temperature, the temperature sensor resistor transmits the information, the control relay loses power and is disconnected, and the two-stage refrigeration system stops working. When inside the refrigerator
Generally speaking, your welding will have some problems, but if you make do, as long as the outside of the welding joint is relatively plump (meaning more and even,), as long as there is no disconnection or leakage of cooling at that time, After using the refrigerant, the refrigerant will generally not come off or leak without external force. Is there any hidden danger? That is, if there is a certain external force, the refrigerant may be ejected due to instantaneous detachment. Of course, it is generally fine.