久久午夜羞羞影院免费观看,最近最好的中文字幕2019免费,亚洲精品乱码久久久久久按摩,久久人人爽人人爽人人AV

POSITION:HOME > NEWS

NEWS

Main Factors of Failure of Plate Heat Exchanger and Preventive Countermeasures

Plate heat exchanger is a new type of high efficiency heat exchanger assembled from a series of metal sheets with a certain corrugated shape. A thin rectangular channel is formed between the various sheets, and heat exchange is performed through the half sheets. The plate heat exchanger is a liquid & mdash; liquid, liquid & mdash; steam for heat exchange equipment. The utility model has the advantages of high heat exchange efficiency, small heat loss, compact and light structure, small occupied area, convenient installation and cleaning, wide application and long service life. In the case of the same pressure loss, the heat transfer coefficient is 3-5 times higher than that of the tube heat exchanger, and the floor space is one-third of the tube heat exchanger, and the heat recovery rate can be as high as 90% or more. As a compact and efficient heat exchange equipment, plate heat exchangers have been widely used in many industrial fields in China and have achieved great economic benefits. However, the failure of the plate heat exchanger also causes certain economic losses to our users. The main reasons are seal failure, fouling blockage and corrosion, which make the heat exchanger unable to use.
1. Analysis of the causes of seal failure and related precautions 
The main reasons for seal failure are pressure, temperature, time and operating conditions.
1.1Pressure 
plate heat exchanger type is detachable, sealed, etc., such as plate-type detachable heat exchanger used under the rated working pressure, leakage, in addition to the equipment in the manufacturing quality, mainly with There are abnormal impact loads in the system, which is not easy for the operator to find. The transient pressure is increased by the impact, and the pressure may be 1 to 3 times higher than the normal pressure, causing the sealing gasket installed in the plate heat exchanger to be displaced, resulting in failure of the seal. Moreover, since the heat transfer element of the device is manufactured by one-time forming of a thin plate, the thickness is 0.5-0.8 mm, the rigidity and the bearing capacity of the seal are relatively poor, and some heat exchanger plates have a long periphery and the impact resistance is relatively poor.  
In this regard, appropriate precautions should be taken: depending on the operating pressure, increase the design pressure of the equipment to 1.5 to 2 times the pressure of use; in use, try to avoid the impact phenomenon in the system; Take measures to increase the thickness of the sheet.  
1.2 Temperature 
A sharp change in temperature also causes seal failure. When the temperature changes too fast, the expansion coefficient of the gasket does not match the elastic deformation and the pre-tightening force of the seal, so that the pre-tightening force of the seal is lowered, and the bearing capacity of the device is lower than the rated working pressure.  
The following measures should be taken to solve this problem: the boosting temperature should be as slow as possible when operating the equipment; the compression preloading spring is designed on the clamping bolt to compensate for the change of the preload.  
1.3Time 
The use time of the plate heat exchanger, as the use time increases, the material of the gasket will also age. The sealing effect is used, which affects the sealing effect of the plate heat exchanger.  
According to the characteristics of the material, the gasket of the appropriate material should be selected, and different gaskets should be used depending on the conditions of use.  
1.4Operating conditions 
The difference in process media can also cause seal failure. A supersaturated steam like temperature will cause the seal to fail for a short time. The saturated steam of the same temperature can form a water film on the surface of the gasket to protect the gasket.  
Selecting the right process medium for the operation, is also a way to ensure the failure of the plate heat exchanger.  
2. Analysis of the cause of clogging and scaling failure and corresponding preventive measures
2.1 Blocking 
plate heat exchanger has a small flow gap, about 2.5 ~ 6mm, the particle debris larger than 1.5 ~ 3mm is easy to block the channel, so that the pressure drop of the device changes drastically, the flow is reduced, heat transfer The effect is reduced and the device is easily disabled. Precautions A filter or flushing device can be placed at the inlet of the media for regular cleaning or disposal.  
2.2 Fouling 
After the plate heat exchanger is used, due to heat transfer or cooling of the medium, fouling occurs. The fouling can cause the heat transfer coefficient of the plate heat exchanger to decrease, and in severe cases, the plate will be blocked. aisle. The plate-type heat exchanger is designed with a large number of support contacts, which are intended to support the flow of the medium. The side effect is that the fluid forms a local stagnation and forms dirt, with time and at a suitable temperature. The calcium and magnesium ions in the cooling water are precipitated and continuously increase to form a honeycomb scale.  
Although the cause of blockage and scaling is different, the impact is the same. The countermeasures against prevention are: plate heat exchangers should not be used in dirty or fouling materials; do not use unsoftened water as cooling medium, and temperature should have relevant requirements to avoid sensitive temperature zones where calcium and magnesium ions are precipitated. . Moreover, when the new system is put into operation, the heat exchanger should be separated from the system for a period of time, and then the heat exchanger should be put into the system.  
3. Analysis of corrosion failure and preventive measures
The type of corrosion failure of plate heat exchangers is somewhat etched, crevice corrosion, stress corrosion cracking, uniform corrosion and other corrosion failures. Corrosion is a complex chemical phenomenon, such as rust or scale on the surface of the plate. Pitting corrosion; crevice corrosion at the bottom of the gasket groove or sheet closure; uniform or corrosion of all or most of the metal surface of the contact medium being corroded.  
This should take the following effective precautions: the correct choice of sheet material; regular cleaning of dirt to destroy the conditions and development of corrosion; use non-chlorine-containing binder.  
4. Analysis and measures for design, manufacturing and installation
Due to the high efficiency and energy saving characteristics of plate heat exchangers, it is widely used in many fields, and the processing media are various, and the conditions are different and varied in the production process. The choice of the gasket is the key. If the choice is not suitable, the material can not meet the physical properties of the process medium, the elasticity is not good, and the use of the padding, elongation, deformation, aging, breakage, etc. occurs.  
During the manufacturing process of the sheet, the residual stress generated in the stamping is used in a corrosive environment, which will cause stress corrosion and directly damage the sheet.  
The surface of the plate is not flat, the equipment is not easy to install and centered during installation and maintenance, which makes the pressing force uneven, affecting the seal and causing leakage.  
In this regard, the alignment should be installed as much as possible in the installation, so that the pressing force is even, so that it can be kept tight during use and does not leak.  
2019/05/10 20:17:43 3630 Click

性饥渴的老妇教我玩她| 亚洲乱色熟女一区二区三区蜜臀| 年轻18gay白嫩青少年| 国产精品久久久久精品三级| 天堂MV在线MV免费MV香蕉| 与亲女洗澡时伦了| 精品国产青草久久久久福利| 国产xxx69麻豆国语对白| 丰满少妇a级毛片| 久久天天躁狠狠躁夜夜爽| 久久人人爽人人爽人人片AV高清| gogogo高清在线观看视频| 无码国产精品一区二区免费模式 | 揉腿却揉到两腿之间是湿的| 久久亚洲美女精品国产精品| 闺蜜男友猛撞h花液h深| 亚洲AV无码成人精品区在线观看| 欧美疯狂做受XXXX高潮小说| 国产精品成人第一区二区三区| 久久久久亚洲精品男人的天堂| 99精产国品一二三产区区别电影| 麻豆亚洲AV成人无码久久精品 | 亚洲综合国产成人丁香五月激情| z0ozo0人善之交另类| 军人野外吮她的花蒂无码视频| 放荡的小峓子2中文字幕| 99精品国产一区二区三区不卡| 野外真人实战cs| 国产精品久久久久免费A∨| XXXXX性BBBBB欧美| 老司机福利导航| 无码少妇一区二区三区芒果| 男男做a爱过程免费视频| 内射人妻无码色AB麻豆| 色戒2小时38分在线观看| 多男用舌头伺候一女| 羞羞答答麻豆国产免费观看| 粗大挺进粉嫩紧窄女朋友小说| 国模冰莲极品自慰人体| 内分泌失调怎么调整过来| 三个男人添一个女人下身|