English name: cooler Air Heat Exchangers
One of the items that most refinery units and petrochemical to reduce the temperature of the fluid are used for cooling air. Air cooling in the air with the ambient temperature of warm pipes containing fluid collide, and reduces the temperature of the walls of the pipe and the fluid inside the pipe temperature is thus reduced. The standard length of the pipes used in the converter cooling air, typically 20, 30 and 40 feet. One of the issues which in the case of air cooling exchanger is important, the ratio of the area of the Bay area fan. This ratio will converge and its value on the fan in the air cooling exchanger should not be smaller than the 4.0. Air cooling exchanger is usually the two are used in the following arrangement:
– Forced Draft
– Induced Draft
This converter is for reducing the temperature of the fluid inside the pipe, the air of the environment. The main components of this converter include one or more pipes that are exposed to air flow fan, fan motor and it equipment, fan speed controller and navigation equipment for the stream. The warm fluid flow in this converter, after passing through a nozzle of the tube that will be arrived in the vicinity of the fan. These pipes according to the outer wall of the blades on the tubes, heat transfer work faster. In the fluid passes from the vicinity of the fan, any set of tubes containing hot fluid called a Bundle that includes several pipes. Usually a few Bundle of parallel with each other on a passing fan. To this collection a Bay. In some cases the two fans in the form of a series of parallel flow on the Bundle of a Bay. This mode consists of two tubes containing the Bundle of warm fluid which is adjacent to two fan-made series of passes. usually to cool the hot fluid by air-cooled converter in the industry that a few of the Bay are located in parallel is used. To set this Bay, Unit. The diameter of the fan used in the converter air-cooled in 3 to 28 c-Fu. However, usually the fan with a diameter of 14-16 ft of fan used in the petrochemical industry. Figure 2 two-Bay Bundle with 4 as stated, the air with the ambient temperature to warm pipes containing fluid collide, and reduces the temperature of the walls of the pipe and the fluid inside the pipe temperature is thus reduced. To increase the rate of heat transfer from finned pipes are used. Finned tubes in several air-cooled converters are used for. One of the most important types of these blades, the blade (Extruded fin), which is usually made from aluminum. How to build the blades this is a layer of metal is placed on the corresponding pipe and then this layer with pressure by another device installed on the pipe. The format of this device in a way that serves the external surface of the pipe at the end to form a spiral blades or other shape comes in and the external surface of the pipe. These blades are usually at a lower temperature of 200 ° c is used. Figure 3 is a two-Bay Unit that includes six Bundle. Another type of blade used in the converter, the air cooling of the blade (Embedded fins). These blades are also usually made of aluminium or steel are made. These blades are shaped like thin rods with circular or square cross-section, which warm fluid inside the tube containing the wall collapsed. In Figure 6, four of these blades are typically shown in schematic. According to this we find that this blade from a large variety. Use this blade in the high-temperature converter and discontinuous work processes are used.
Operation and adjustment of machine with temperature changes
Air for cooling the warm air in the summer and have designed temperature changes as a result of seasonal changes can cause changes in the cooling is not desired, they may be شودکه. One way is to reduce the air flow rate to the amount of fluid inside the heat transfer tube for less. To do this use the chndsreth engine. Often two different speed motors can work. The second way to control, placing Louvers (chorus of the sphere) as a cover or roof on part of pipes and the other the use of variable-Pitch with fan (the fan blades have a tilt feature)
Louver control functionality. This control can be automatic or manually by electric motors or air systems of the temperature and pressure controllers to command system. Louver are usually for fixed-speed fan. In the variable slope with fan, fan blade tilt to provide the required air flow according to the temperature and pressure of the system. The angle of the blade when the temperature drop finds reduced and this makes lower fan. Hydraulic engines can also reduce the fan speed. When the little air flow is required, the fan power is also reduced. An other solution for the control of the heat transfer fluid flow control system in both directions. In this case instead of air flow (as the fluid inside the pipe cooling) control the flow of hot fluid inside the pipes. The two current systems is that a nozzle at the bottom there is a header field entry. The natural flow of the fluid nozzle photo. In some high viscosity fluids with sometimes this is the only way to prevent the fluid from freezing. The last change that can be brought into existence in the air temperature, especially in cold weather, use a hot air flow circulation. This is because the system and temperature control to prevent fluid freezing is used. Hot air circulation system with automatic variable fan and Louver. A stream of warm air to the internal and external circulation of two types of circulation Division. The internal circulation (Internal recirculation) to this case is that a constant speed fan and a variable-speed fan together. In this mode the fan speed to the bottom half of the fixed air Chamber the flow variable-speed fan that throws with fashion photo works (i.e. the air from the top and bottom sides of the Chamber can مکد dmad), hot air above the first Chamber that has been driven by high technology, with the incoming cold air from the outside, the bottom side of the Chamber to dmad. The upper chamber Louver automatically by sensors of the temperature control system. If the temperature of the system, increase the Louver (shutters), are opened. In the normal mode is fully open Louver, and both are in the standard mode the fan speed. The inner circulation cooling with a mode between no air circulation and the mode is completely controlled by the external circulation. Of course, this method is less expensive than external circulation and less pressure loss. However, this method does not completely prevent fluid from freezing. Because no control on the output air temperature. In the case of external circulation of the fan with variable speeds and two in normal mode on low speed with the ability to use slop change. In this design the Louver manually open and close. The highest temperature of the fluid, controlled by the Louver. When the temperature of the fluid close to the internal air temperature, external louver opens. This match by a controller that is located on the fan and the temperature of the air can be done sans the circulation fluid temperature control for accurate and avoid its application of freezing are plentiful. One of the benefits of air cooling heat exchanger uses this incinerator at low points of water. At low water, conventional converters and parts of cooling towers due to the need to water, cannot be used. Therefore, one of the best methods for fluid cooling without the use of water, the use of air cooling heat exchanger. Air cooling exchanger problems of hot air circulation system can be at any time of the year are problematic. These systems in the summer to reduce the severity of toanshan. The most cause it can be expressed as follows: when the cooling of air near the building and put down in the direction of the wind, the warm air outlet of the cooling by wind flow carry and after dealing with some of the warm air back into the system again. Put coolant air away from such barriers is the best solution. Forced air cooling of the type of return are always prone to hot air. Especially if it is cooling in place close the ground force because the differences between the low-speed air streams to be back turned to air the fundamental problem. As a result, such systems must be installed at a height of. Sometimes dry air cooling system for cooling with wet series for the series to be used. Of course, if you need to change the temperature of the system there is a lot in this process, enter the first part of the fluid tubes, finned tubes, and then enter the dry wet parts. After additional air humidity by May was گیرهایی, on dry وزیده pipes. In wet cooling system the cooling spray water into the air and then the wet air blown on the pipes. Of course, it must be the sex tube of some kind that focuses on the effect of the humidity down. شکل6-in the form of a converter cooling air and a cooling tower specifically c k and parallel work cools down the hot fluid input. Air cooling exchanger dimensions standard length of pipes used in the converter cooling air, typically 20, 30 and 40 feet. The width of each Bay is also from 2.1 up to 1.9 meters. Usually use the longer tubes reduces the cost of making air cooling exchanger. The diameter of the pipes used in the converter air cooling in the range 16 to 38 mm. Blade height of pipes as well as in the domain of 7.12 up to 4.25 mm. The number of spokes in each inch of pipe length FPI (Fin Per Inch), from 8 to 11 blades. Blades are effectively increases the external surface of the pipe would be to fly a finned external area can be 12 to 25 against the external area of the tube without the blade. How to wrap the pipes, usually in the form of triangular shape and distance in mm up to 6.1 de 4.6 hado between adjacent tube blades can be considered. Air cooling exchanger in increasing the number of pipes increases the exterior pipes and increases the speed of the fluid in the pipes to reduce the diameter of the pipes is that this increases the rate of heat transfer. On the other hand, the increase in the number of pipes increases pressure loss in pipes, increasing the cost of construction of the converter and increase the amount of power required for the fan. With this description it is obvious that in the design of air cooling exchanger considering these effects shall be determining the optimal number of tubes. With regard to the necessary length to width ratio being logical in air cooling exchanger is usually 3 to 8 rows of pipes, fin, used for any fan. It should be noted that the use of the four rows of pipes from other metdaolter. In this episode of the converter according to the status of the Partition, how to move the fluid Pass page in the tubes. Aluminum blades are usually for pipes used to level against more air and relatively low heat transfer coefficient of air to compensate. Finn, a variety that they have is that it will Extrude fin fin, because more cuddly economic use. A base diameter of pipes can be up to approximately 8.5 inches, the height of the Finn about 1-in. A header typically made of carbon steel and aluminum fin are made. Brass alloys and stainless steel also has similar properties but are both more expensive than carbon steel. The most economical and the most common type of the fans horizontally. Of course, for the feature the freezing سیالاتی. The pipe must have a minimum slope of 1.8 inches. In most cases the problem of freezing and Jude does not come because of this and because the cost of being on this method is usually the pipes are placed horizontally. Angled and vertical systems for maximum efficiency when it is needed (for example in liquid storage systems) are used. Often angled, angular system about 30 degrees with the horizon.
Air cooling exchanger suckers
English name: Cooler Air Induced Draft
In this makeup tubes in part the high fan tech suckers means the set of pipes. The advantages and disadvantages have induced type. In this type, the air in different parts around the pipes to the proper syntax would be distributed and the possibility of returning to the warm-air fan is less than هواگیری. The influence of the Sun and rain and hail on the tube are نیزکمتر because 60% of the surface is covered and the impact of the natural flow in the system. The disadvantages of this system are as follows: the more power is needed because the hot air passing through the fan exposed pipes. The temperature of the warm air outlet tubes burned out section should be limited to approximately f200. Because the possibility of a deterioration of the blade and bearing and belt and other parts of the fan on the warm air flow there. The other flaw is that fan parts for repair, the less are available.
Converter cooling air blower
English name: Forced Draft Air Cooler
In this makeup tubes in part of the fan blower fan means the subset of pipes. In the type in the upper tubes Forced technologists. In this way, the effect of warming the incoming air, on top of the natural air suction pipes upwards. Therefore, the fan power will be less. On the other hand, in this kind of converter fan parts for repair, are easily accessible. In the meantime this type converter has more compatibility in سردسیر areas. But this system is unlike the advantages mentioned have disadvantages as well, including lack of proper air distribution can be between the pipes and allow hot air to back because of low speed output of the air pipes. In the meantime because the pipes are exposed to the Sun d d, rain and hail have put the rate of depreciation.