Analysis of basic knowledge of pump maintenance and cause of failure

Early car engines did not have an important attachment we now consider essential - the water pump, when the liquid cooling medium used was pure water, mixed with a little bit of wood alcohol at most to prevent icing. The circulation of cooling water depends entirely on the natural convection heat phenomenon. After the cooling water absorbs heat from the cylinder block, it naturally flows upward and enters the upper part of the radiator. After the cooling water cools down, it naturally sinks to the bottom of the radiator and enters the lower part of the cylinder block. The use of this principle of thermosyphon can barely complete the task of cooling. But soon after, pumps were added to the cooling system to allow the cooling water to flow more quickly.
Modern automotive engine cooling systems are generally used centrifugal pumps. The most plausible installation of the pump is at the bottom of the cooling system, but most of the pumps are located in the middle of the cooling system and a few of the pumps are located on the top of the engine. Pumps placed on the top of the engine are prone to cavitation. No matter in what position, the pump pumps a lot of water, such as a V8 engine pump pump water, idling about 750L / h, to about 12000L / h at high speed. Pump technology, pump technology, valve technology, pump CFD, pump numerical simulation,
From the service life point of view, the biggest change in the design of the pump was the appearance of ceramic seals a few years ago, which is more wear-resistant than the previously used rubber seals or leather seals, but it also has easy Disadvantages of being scratched by hard particles in the cooling water. Although the pump seal to prevent the failure of the design has been continuously improved, but so far can not guarantee the pump seal is not a problem. Once the seal leaks, then the pump bearing lubrication will be washed away.
Troubleshooting In the past 20 years, the durability of the car has been greatly improved, then the service life of the pump is longer than it used to be? not necessarily. Today's pumps still need a lot of replacement work, the car about driving 100,000 km, the pump will have the possibility of failure at any time.
Pump fault diagnosis is generally relatively simple. In the event of a leak in the cooling system, the smell of hot antifreeze can be heard, but a check must be made to see if the cooling water has escaped from the pump shaft seal. Use a small mirror and light to see if there is a leak in the pump vent. To be regularly maintained, pay attention to check the tank coolant loss.
Leakage is the number one fault pump, noise is the second fault, due to bearing scratches caused by the shaft of the pump killed the phenomenon is very rare. Once this happens, wind and heat sinks get damaged.
Although it is common to find in pump documentation serious corrosion of pump impellers, impeller corrosion is not a common occurrence if normal maintenance is done. When you see the coolant red, rusty color, it is estimated there is a problem of impeller corrosion. At this time you need to check the pump coolant circulation, the radiator can be part of the coolant, so that the water level just above the water pipe, and then preheat the engine so that the thermostat in a fully open position. When the engine speed is 3000r / min, you should see a good water cycle. Another possible problem is that the pump impeller appears loosely on the shaft.

The cause of the malfunction As for the pump failure, some authorities think that the same belt-driven attachment more and more, so that the lateral load is too large. As one sealing expert put it: "There is evidence that the resonances created by the same belt-driven accessory have different frequencies that can damage the pump seal." Another problem with pump failure is that the serpentine belt's The tensioning device exerts a great lateral load on the pump. Cavitation is another problem for water pumps. Corrosion usually occurs on the water inlet side of the pump, so a low pressure radiator cap is usually installed. When replacing the pump, it is advisable to install a new fan clutch, as losing the balanced clutch may cause problems for the pump.
Some experts believe that overheating and lack of maintenance is also a pump cause problems. If the coolant loses its ability to lubricate the seal, the seal will be scratched. In addition, the pump fails, may also be due to the poor quality of the pump itself.

Learning the belt Old models generally use the ordinary V-shaped belt, the new model may be used is a serpentine belt. If the old model of the pump installed in the new model, there may be a problem in the direction. Because the serpentine belt may drive the pump impeller in the opposite direction of the V-belt, the pump rotates in the opposite direction, causing the coolant to overheat.
More and more engines now use a camshaft timing belt driven pump, which has the benefit of not driving the vehicle without rotating the pump and shortening the length of the engine. It must be emphasized that after a suitable period of time, the timing belt should be replaced. Sometimes see such a situation. The pump was damaged within a short period of time after installing a new timing belt, generally due to increased belt tension. Therefore, when installing a new pump, do not recklessly switch to a new belt.

Pump Maintenance Here to talk about the coolant problem, and some maintenance considerations. In modern cars, which often use all-aluminum engines with higher heat loads, replacing the coolant annually seems to be the best way to prevent problems. However, antifreeze formulations are now very advanced, so that cooling fluid replacement interval is continuously extended. First recommended coolant replacement cycle of 3 years, then extended to 4 years, now GM recommended in some models is 5 years or 250,000 km. The current coolant formulation avoids the problems often experienced with cooling systems due to extended coolant replacement. The new coolant has the ability to resist the corrosion of carboxyl compounds, namely silicates, phosphates and inorganic substances that block waterways that are not found in common ethylene glycol. Although the new coolant is more expensive than conventional coolant, it is still cost-effective to ensure that the pump is working properly for a long time. In order to maximize the long life of the coolant, the replacement of the need to thoroughly clean the cooling system.
Here to talk about the quality of antifreeze. The term "antifreeze" is a misnomer because it uses antifreeze not only for antifreeze, but also for resistance to corrosion, lubrication of the pump seal, and increased boiling point. Therefore, you should not use an unknown brand of antifreeze, it may contain inappropriate additives and harmful PH value.
The severity of the cooling system leakage problem can not be underestimated, which not only destroys the intake air in a predetermined coolant flow pattern, causes hot spots, but also greatly aggravates the pump corrosion. If the amount of coolant is not enough for a long time, it will cause overheating of the engine, but steam corrosion will not only damage the radiator but also generate other pump problems.

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Finned Tubes

A finned tube is a heat transfer device consisting of many parallel metal fins commonly used for heat dissipation and cooling applications. Finned tubes increase the surface area of the pipe, thus increasing the heat transfer efficiency. Finned tubes are commonly used in applications such as air coolers, automotive radiators, condensers, and evaporators. They are also used in industrial heaters and refrigerators to increase heat transfer surface area and improve efficiency.