Freezers and refrigeration princ

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PTI and freezers refrigeration principle 1. PTI what

The so-called PTI, the English called PRE-TRIP, Chinese meaning for the pre-trip inspection. All refrigerated containers are equipped with refrigeration machinery, refrigeration machines are generally used lightweight aluminum frame construction, is set for the integration of a variety of electrical cooling and warming autonomous refrigeration unit. The unit is mounted on the front end of refrigerated containers and as a container front wall. And each suitcase in refrigerated containers until the customer, must ensure that the machine is in a normal state, there is no fault, so that they could play after loading refrigerated / frozen effect. And how to ensure that the machine is operating normally, and that is through the PTI this check to be realized.

   CSCL currently using two brands of cold machine, one is Mitsubishi, another is a Carrier, and to Carrier-based. All machines are on the control panel keys PTI this operation by operating the key, the machine can automatically PTI checked (AUTO PTI), the unit will use to measure and compare the internal logic to automatically detect the various parts of the unit and to provide " PASS "(pass) or" FAIL "(failure) display to indicate that the test results for each one. If "FAIL" appears, then the relevant technical staff must carry out further testing to identify the cause of the fault and make the necessary repairs. Until the entire AUTO PTI to complete and no FAIL, indicating that the AUTO PTI through the machine without failure.

   PTI agreement by all Division I repair company / repair yard completion, the current Division I program in addition to AUTO PTI PTI must pass, but also added some additional projects, such as housing conditions check some basic values ​​measured current etc., and the reason why added some items, it is based on past experience, the AUTO PTI under the premise of some vulnerable parts of the re-testing to ensure that the machine properly.

(2) Refrigeration

All refrigeration equipment, including air conditioners, refrigerators, etc., in fact, the principle is the same, by the four essential components, compressor, condenser, throttling device, evaporator. In these four main components of the base, along with some other auxiliary components to form a complete cooling unit. The principle is as follows:

The refrigerant in the evaporator and the object to be cooled heat exchange occurs, the heat absorption of the object to be cooled and evaporated, and the resulting vapor is the compressor suction pressure, the compression pressure after discharge. The high pressure compressor discharge gas refrigerant in the condenser cooling medium is at room temperature (water or air) cooling, condensed into high pressure liquid. High pressure liquid flows through the throttle device, into a low pressure, low temperature wet vapor into the evaporator, in which the pressure in the evaporator the liquid refrigerant vaporized again. Again and again.

Our cooling mechanism specific to the cooling process, the driver set of internal I refrigerants used R134A, starting from the compressor, the refrigerant gas is compressed to high temperature and high pressure gas, the gas then enters the condenser, through the coil and the air cooling fins (the air as the outside air, cooler parts of a condenser Condenser fan air flow by turning the drive), the saturation temperature of the refrigerant gas is reduced, is condensed to a high pressure / high temperature liquid, the liquid and then through the throttle device , part of the liquid evaporates into a gas, the remaining liquid through the evaporator, and the relatively high temperatures inside the container return air heat exchange (unit evaporator cooler parts of the evaporator fan to force the air flow inside the container), the refrigerant absorbs the return air After the heat of the coil in the evaporator vaporizes into a low-pressure gas again, back to the compressor, to complete a refrigeration process.

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