The cooling of each auxiliary machine is a low-temperature cooling and fresh water cooling system which is cooled by a low-temperature fresh water cooler. The low-temperature one-way is boosted by the low-temperature water pump provided by the auxiliary machine, and flows through the air cooler and the oil cooler. Then, the one-way check valve flows back to the low-temperature water cooler; after high temperature, the high-temperature water automatic control valve (automatically adjusts the entry amount of high-temperature water and low-temperature water, controls the temperature of the high-temperature water), and is boosted by the high-temperature water pump to cool the diesel engine. Each cylinder liner, cylinder head and supercharger are then partially returned to the high temperature water automatic control valve and the other portion is returned to the cryogenic water cooler via the one-way check valve. 2 high temperature cooling water low pressure / high temperature power generation diesel engine parking failure One day, during the rotation of the Panama Canal, the auxiliary units No.1 and No.2 were operated in parallel, and the three main air compressors were connected in parallel (starting at different compressed air pressures). (1) The fault suddenly, No.1 auxiliary machine high-temperature cooling fresh water low-pressure alarm, the temperature rises quickly, some load still stops the parking protection limit temperature and automatically stops after unloading; another parallel operation No.2 auxiliary machine bears all the load independently The high temperature cooling fresh water pressure is normal. The emergency start No.3 auxiliary machine is operated in parallel with the No.2 auxiliary machine, and the other engineers are emergencyly called to assist in handling the emergency. After the No.1 power generation diesel engine was automatically stopped, the high-temperature cooling water system was vented and checked, and it was found that air escaped from time to time, but the quantity was not much. No.3 auxiliary machine, high temperature water low pressure alarm appeared soon after operation. In view of the air in the No.1 auxiliary machine high-temperature cooling water system, the high-temperature cooling water of the No.3 auxiliary machine showed a low-pressure alarm and deflation check, and it was found that there were also air escapes from time to time. The exhaust temperature of the main and auxiliary engines is basically uniform; the main and auxiliary machines are exhausted without white smoke; the No. 2 auxiliary machine is deflated and no air escapes; during the failure, the host's high temperature cooling fresh water pressure is normal and there is no fluctuation. (2) Emergency measures The following emergency measures were taken to prevent further expansion: the auxiliary machine, the high-temperature cooling water system continuously deflated, reduced the air in the cooling fresh water, and prevented the cooling fresh water from losing pressure; Add additional personnel to strengthen the cabin inspection, and so on. (3) Method of venting fresh water system The venting lines of the three auxiliary high-temperature cooling waters are thin and long, and are finally connected to a main pipe and then connected to a higher-position expansion water tank. Therefore, the method of rapid deflation is: 1 to close the ventilation valve of the high-temperature cooling water system of the auxiliary machine; 2 to loosen the quick joint or flange venting at the inlet end of the venting valve and the high-temperature cooling water outlet manifold (reducing the outgassing resistance) ). 3 Find the source of air in the cooling fresh water system The low-temperature and high-temperature cooling water systems of the wheel auxiliary machine are each supplied by a centrifugal pump, which is continuous and stable; the disadvantage is that if there is air in the cooling water, it is easy to suck, causing the cooling water supply to be interrupted. Cooling fresh water always dissolves a small amount of air. The high-temperature cooling fresh water absorbs the heat from the cylinder liner and the cylinder head and the supercharger. The temperature rises, the air solubility decreases, and some dissolved air escapes. Therefore, the main and auxiliary high-temperature cooling water systems are generally provided with a venting line. The venting pipeline is designed based on the escape of air in the cooling water system. The speed of venting air is higher than the speed at which the gas escapes. The airbag does not form an airbag, the pump does not suck, and the cooling water is not interrupted. If the pressurized air enters the cooling fresh water system, the air volume in the system is greater than the ability of the venting line to vent air, and the airbag may be formed in the system, causing the pump to be emptied and the cooling water to be interrupted. The cooling water pressure is higher than the atmosphere. Air can only enter cooling water from equipment above the cooling fresh water pressure. In view of the No.1 auxiliary machine automatic stop and the No.3 auxiliary machine operation, the high-temperature cooling water system has air release from time to time. It is preliminarily determined that the cause of the No.1 auxiliary machine jump is that the pressurized air enters the cooling fresh water system. The entire cooling fresh water system is connected. The air in the high-temperature freshwater branch may come from the high-temperature branch or from the low-temperature branch; similarly, the air in the low-temperature fresh-water branch may come from the low-temperature branch or from the high-temperature branch. For example, a sister ship's main engine low-temperature cooling fresh water pipe air cooler leaks, when the charge air pressure is high, the air enters the low-temperature cooling fresh water system and then enters the auxiliary machine high-temperature cooling water system, the auxiliary machine high-temperature water pump sucks, the high-temperature cooling water cuts off. And the fresh water is cooled for a short time, and the auxiliary machine jumps and stops. Therefore, it is necessary to check the equipment above the cooling fresh water pressure one by one from the main engine and the auxiliary machine (both high temperature branch and low temperature branch) and the air compressor and refrigeration device to find the source of the air in the cooling fresh water. 3.1 High temperature cooling fresh water branch of main engine and auxiliary machine The host cools the freshwater branch at high temperature. During the fault, the pressure is normal and there is no fluctuation. It can be excluded first. The high-temperature cooling freshwater branch of the auxiliary machine: no cracks and cracks occurred before the fault; there was no particularly low temperature in the cylinder and white smoke in the chimney during the fault, which basically eliminated the splitting of the cylinder liner and the cylinder head of the auxiliary machine. The possibility that the exhaust pressure of the auxiliary turbocharger before the turbine is lower than the high temperature cooling fresh water pressure, the smoke cannot leak into the cooling fresh water system. Basically, the possibility of gas entering the high temperature and fresh water branch of the main and auxiliary engines is excluded. 3.2 Low-temperature cooling freshwater branch of main engine and auxiliary machine This way, you don't have to consider the oil cooler, just consider the air cooler. During the failure, the load of the main engine is low, the supercharging pressure is lower than the fresh water pressure, and the pressurized air cannot leak into the cooling fresh water system; although the load is high, the actual supercharging pressure is lower than the cooling fresh water pressure, and the air cannot leak into the cooling. Fresh water system. Actual verification, when the main unit and the auxiliary air cooler were opened, the air was discharged, and only air was released without residual water. It can eliminate the possibility that the primary and secondary air-charged air enters the low-temperature freshwater branch. 3.3 Air compressor and refrigeration unit branch The main bearing in the middle of the bearing cooling water, etc., it is impossible to have pressurized air; air conditioners, ice machines, etc. are operating normally; and during the failure, the ship is maneuvering in the Panama Canal, and the main air compressor is frequently started, so three main air compressors should be considered. The ship has no secondary air compressor). Sequin Embroidery Machine,Embroidery Machine for Sale,Single Sequin Embroidery Machine HEFENG COMPUTERIZED EMBROIDERY MACHINES LIMITED , http://www.hk-embroiderymachine.com
Analysis of the treatment of machine cooling water parking problem
1 central cooling fresh water system