Views:0 Author:Site Editor Publish Time: 2020-05-14 Origin:Site
The plate heat exchanger is a new type of heat exchanger formed by stacking a series of corrugated metal sheets. Thin rectangular channels are formed between various plates to exchange heat through the plates. Plate heat exchangers are ideal equipment for liquid-liquid and liquid-vapor heat exchange.
It has the characteristics of high heat exchange efficiency, small heat loss, compact and lightweight structure, small footprint, easy installation and cleaning, wide application and long service life. Under the same pressure loss, its heat transfer coefficient is 3-5 times higher than that of the tube heat exchanger, it covers an area of one third of the tube heat exchanger, and the heat recovery rate can be as high as 90%.
The plate heat exchanger in the lubrication system is an important part of the steam turbine device. As the oil absorbs the heat generated by friction in the bearings and other parts during the circulation process, the temperature continues to rise, in order to ensure the reliable operation of the unit. It is necessary to control the oil temperature within the specified range (required not to exceed 60-65°C and not lower than 35-40 °C). If the temperature is too high, the bearings and other components may be overheated and damaged. And it will reduce the service life of the lubricating oil. Too low a temperature will increase the viscosity of the lubricating oil, increase friction and labor, and even cause vibration of the machine. Therefore, a plate heat exchanger is used to reduce the temperature of the lubricating oil by adjusting the flow of cooling water.
The chip type or corrugated type should be determined according to the actual needs of heat exchange occasions. For the case where the flow rate is large and the pressure drop is small, the plate type with low resistance should be selected; otherwise, the plate type with high resistance should be used. According to the fluid pressure and temperature, determine whether to choose detachable or brazed. When determining the plate type, it is not advisable to select plates with too small veneer area, so as to avoid too many plates, small flow velocity between plates, and low heat transfer coefficient. This problem should be paid more attention to for larger heat exchangers.
The process refers to a group of parallel flow channels in the same direction of movement of a medium in the plate heat exchanger, and the flow channel refers to the medium flow channel composed of two adjacent plates in the plate heat exchanger. Generally, several flow channels are connected in parallel or in series to form different combinations of cold and hot medium channels.
The flow combination form should be calculated based on heat exchange and fluid resistance, and determined when the process conditions are met. Try to make the convection heat transfer coefficients in the cold and hot water channels equal or close, so as to obtain a good heat transfer effect. Because the convective heat transfer coefficients on both sides of the heat transfer surface are equal or close to each other, the heat transfer coefficient obtains a larger value. Although the flow rate between the plates of the plate heat exchanger is not equal, in the calculation of heat transfer and fluid resistance, the average flow rate is still used for calculation. Because the U-shaped single-process nozzles are fixed on the pressure plate, it is easy to disassemble and assemble.
With the continuous development of refrigeration technology, new requirements have been put forward for the use of refrigerants, such as carbon dioxide, hydrocarbon and other refrigerant refrigeration systems. Iridian always pays attention to the new development of industry technology and continuously improves its products to adapt to it.