Talking about the Misunderstandings Existing in the Selection and Purchase of Plate Heat Exchangers
Plate heat exchanger is a new type of high efficiency heat exchanger assembled from a series of metal sheets with a certain corrugated shape. 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, and the heat transfer coefficient is higher than that of the tube heat exchanger under the same pressure loss condition. It is 3-5 times higher and covers one-third of the tubular heat exchanger. It is a widely used heat exchanger and has won unanimous approval from customers. However, in the process of purchasing plate heat exchangers, we found that customers also have many misunderstandings in understanding and operation. Because of these misunderstandings, they have caused many unnecessary economic losses and troubles, mainly in the following Aspect:
Miscellaneous 1: The plate heat exchangers of foreign brands are definitely better than the plate heat exchangers of domestic brands. In daily work and life, there are always many people who think that "the foreign moon is more than the Chinese circle", and even has become a kind of inertial thinking. But in fact, "China's moon is also very round". Plate heat exchanger products are not a lot of difficulty in production and manufacturing as a conventional equipment with not much technical content. If the plate heat exchanger products of foreign brands are better than domestic brands, it can only be said that the development of new plate types, the application of new materials, the development of new application fields, the replacement of the matching design software database, and the use of materials. The quality is better than domestic brands. These advantages are based on the Western countries attaching importance to and developing various types of experimental platforms and attaching importance to the practical transformation of research results and the use of large computer systems for the simulation design of various products. These are indeed unmatched by current domestic conditions. However, China has the strong product imitation ability of the world today. It has always been adhering to the "advancedism", focusing on foreign advanced product technology, introducing, absorbing, and imitating products with completely consistent performance is our strength. This is also reflected in the plate heat exchanger. It is no exaggeration to say that at present, foreign advanced plate heat exchanger plate types can find completely interchangeable and universal products in China.
Miscellaneous 2: Inquiry on plate heat exchanger products based on data from one heat exchange area. In the sales process of heat exchanger products for many years, we have met countless customers to report a heat exchange area, tell the product material, and then tell a product pressure level to conduct product inquiry. Sometimes some customers even confidently say that this heat exchange area is determined by the design institute. In fact, this is not a sensible inquiry method for customers, because the plate heat exchanger is a non-standard equipment, based on the parameters of the heat transfer process required by the customer, considering various factors (including water quality). Factor, system configuration requirements, use and maintenance factors, etc., determine the product caliber, determine the plate type, determine the process combination, determine the assembly method of the plate, and determine an economical and reasonable plate heat exchanger product. Model, according to the identified product model, in order to know the accurate heat exchange area data and accurate product cost, in order to make a quote. Even if the heat exchange area you get is provided by the design institute, even the design institute also specifies the nozzle diameter, material requirements, and pressure rating of the heat exchanger. However, the design institute is not a manufacturer of heat exchangers. They are only based on the operating parameters required by the system and the conventional heat transfer coefficient empirical values. A design margin is large, and the heat exchange area is conservative and conservative. Often, this The heat exchange area is only a big deal, and can not be used as a basis for the definition and quotation of plate heat exchanger products, and can only be used as a reference. In fact, the heat exchanger coefficient and plate thickness of each plate type and plate type used by each heat exchanger manufacturer are different. The same design conditions, the design scheme and heat exchange area issued by different manufacturers will certainly not be the same. Even the same heat exchanger manufacturer, for the same design parameters, different designers may have different product models and heat exchange areas because of different design considerations. Therefore, plate heat exchangers The model of the product cannot be reversed according to the heat exchange area, and it is impossible to quote the product according to a heat exchange area. The same heat exchange area, can have different caliber specifications, you can choose different thickness of the plate, you can choose a variety of gasket materials, you can have different process combinations, you can use different plate types, you can use countless kinds of plates The combination of films, these directly affect the price of the product. The most important thing is that when you only ask for a heat exchanger area and ask for a quote from a heat exchanger manufacturer, you have already indicated that you are a good, non-professional layman. If you encounter an irresponsible heat exchanger production unit, Simply introduce a heat exchanger product through the heat exchange area, and report to you a very cheap price. It is very likely that after the product purchase returns, the heat exchange requirements and system matching requirements cannot be met, that is, you have spent money to buy it. Products that cannot be used or used have problems, and it is almost impossible for you to return the goods at this time, because the heat exchangers provided by the people do meet the heat exchange area you require. Therefore, Jiangsu Bingke Heat Exchange Equipment Co., Ltd. solemnly reminds all new and old customers that the plate heat exchanger is a non-standard custom equipment, which needs to be carried out by the product designer of the heat exchanger manufacturer according to the process purpose and process parameter requirements. The professional design and shape can be determined after the design is finalized. Regular heat exchanger manufacturers will not determine the product model and quotation according to a heat exchange area, and will definitely ask you for the data required by the design parameters of the heat exchanger, and provide you with heat exchanger design selection according to the required parameters. The parameter list and drawings, as an annex to the contract, require you to sign and confirm. Those units that can arbitrarily quote you according to the heat exchange area will never be a regular heat exchanger production unit. Please be careful to choose. If you choose a problem, the adverse consequences will definitely be for you and your unit. bear.
Miscellaneous 3: The larger the heat transfer area of the plate heat exchanger, the better. This is a misunderstanding not only in the customer's consciousness, but also in the minds of many plate heat exchanger professionals. As the saying goes, "It's too late", use this idiom to explain this misunderstanding. It can be said that it is appropriate. Everything has a degree. When it comes to this degree, many of the ideas that are taken for granted are actually wrong. For plate heat exchangers, the larger the heat exchange area, the better. This is a typical example. It is well known that the larger the plate heat exchange area, the greater the heat exchange capacity of the heat exchanger, which means that the more plates, the more channels formed between the plates, the larger the cross-sectional area of the fluid, the heat transfer in the heat transfer. In the case where the fluid flow rate of the device is constant, the smaller the fluid throughput of the channel between the single plates, the lower the flow velocity of the channel between the plates, and the smaller the pressure loss of the fluid passing through the heat exchanger. As the heat exchange area increases, the heat transfer coefficient will gradually decrease. And what does this mean? It means that the larger the heat exchange area, the smaller the flow rate between the plates, the lower the flow velocity between the plates, the flow mode of the fluid in the heat exchanger channel will gradually change from turbulent flow to laminar flow, and even some channels may have no fluid passage. When the fluid cannot fill the channel between the plates, even the heat exchanger directly loses the heat exchange capacity of a part of the channel. The consequence is that the heat transfer capacity is reduced, the self-cleaning ability of the fluid to lose the shearing effect on the plate, easy to scale, easy to block, easy to appear in the bubble zone, causing leakage in the heat exchanger, changing The maintenance cycle of the heat exchanger is shortened, the maintenance cost is increased, and the service life is shortened. This situation is very common and common in the practical application of plate heat exchangers. The direct reflection is that many customers and even the heat exchanger manufacturers' technicians will say that “plate heat exchangers are good, that is too easy to block, too easy to corrode endoleaks”, but one of the main sources of this problem is to change The bigger the hot area, the better the wrong view. Just because they are aware of the crux of this problem, Jiangsu Bingke Heat Exchange Equipment Co., Ltd. often does not pursue large heat exchange areas for profit maximization when designing plate heat exchangers for customers. It will not blindly obey the requirements of customers and easily increase the heat exchange area. Instead, it will consider the product's service life and the comprehensive cost of maintenance. Under the premise of ensuring heat transfer requirements, comprehensive practical operation will be considered. The balance of heat exchange area, pressure loss, channel flow velocity, turbulent Reynolds coefficient, and design margin, and strive to find a cost-effective product design solution for the whole machine purchase and post-maintenance cost. Therefore, Jiangsu Bingke once again reminds customers: For plate heat exchangers, it is not the heat exchange area that is the better. Too much heat exchange area is likely to be spent on the money that should not be spent. Some hidden problems may cause some unnecessary economic losses to you without knowing it.
Miscellaneous 4: According to the heat exchange area of the heat exchanger, the price per square meter to compare the price, which machine is cheaper to buy which one. In the sales process of heat exchanger products for many years, we will often meet the customer inquiry is to ask directly: “ How much is the heat exchanger 304 of your home? How much is a square of 316? . . . ”. Customers often feel that they have a very good understanding of the plate heat exchanger industry. Every time we encounter such a question, we will feel that we are speechless and do not know how to answer. It can only be said that the way to calculate the price of a plate heat exchanger is unreasonable and inaccurate. No one can buy a square meter of plate heat exchanger for only a few hundred dollars, the same type of the same material, the heat exchange area is not the same, the average price per square meter is not the same, the greater the heat exchange area of the machine The calculated price per square meter is lower. Although there are indeed many plate heat exchanger manufacturers to quote according to what material is a square meter, but there is often a premise, that is, the heat exchange area is more than square meters, will be quoted according to the square meters. There are two kinds of plate heat exchanger manufacturers adopting this quotation method. One type, these manufacturers produce old plate type products, and the heat exchanger products do not have the advanced plate heat exchanger industry. Point positioning design, gasket snap or snap-on quick-fit design, tension bolt lateral locking guide quick-fit design, fluid uniform split design, so product mold precision requirements are low, mold manufacturing cost is low, frame manufacturing is simple, manufactured The product is rough and simple, and the cost is low. There is also a product model of some manufacturers for special mold-making manufacturing, irreplaceable, manufacturers use the whole machine to protect the sales, relying on the later business model of sheet and gasket spare parts profit, such manufacturers' products are often also used. Old plate types, plates and gaskets have a very limited service life. In many cases, these two situations are often reflected in a heat exchanger production unit. However, in general, the heat exchanger production unit adopting this quotation mode basically does not have the ability of rapid maintenance, and the sealing gasket does not have the capability of quick positioning installation and repeated use, resulting in maintenance. Long time, more spare parts replacement. In terms of product selection and design, there is no matching heat exchanger design selection software that can be matched with the product. The products produced by such plate heat exchanger enterprises are basically low-end products in the heat exchanger industry. The characteristics are that the whole machine is cheap, the spare parts are expensive, the product has short service life, and the comprehensive life cost of the product is high. In the high-end imported brands, it is never possible to quote the whole machine according to the amount of money per square. There are many reasons for not to mention more. Their characteristics are that the whole machine is expensive, spare parts are more expensive, and the product has a longer life. The comprehensive cost of product life is high. And similar to Jiangsu Bingke Heat Exchange Equipment Co., Ltd. to imitation of imported brand advanced plate heat exchanger manufacturers, is in the intermediate state, it is not possible to quote the whole machine according to how much per square meter, often in accordance with the whole machine manufacturing The cost plus a fixed percentage of the profit is quoted for the whole machine. Therefore, the characteristics are that the price of the whole machine is reasonable, the price of spare parts is reasonable, the life of the product is long, and the comprehensive cost of the product life is low. From a technical point of view and a business point of view, Jiangsu Bingke always believes that the average average cost of the life of the product is calculated. The annual average cost per life is the scientific, professional, reasonable and accurate data to measure the economics of the plate heat exchanger. index. The total cost of using 3 years is 60,000, the total cost of using 6 years is 80,000, and the total cost of using 8 years is 150,000. That economy, whoever counts it, is definitely an economical solution with a total cost of 80,000 for 6 years! So Jiangsu Bingke Heat Exchange Equipment Co., Ltd. once again solemnly reminds you: buy plate heat exchanger products, can not blindly pursue the low price of the whole machine, in addition to comprehensive considerations heat exchanger manufacturers Corporate reputation, product technology, productDesign and selection capabilities, product manufacturingCapabilities, practical application experience , designrecommendation habits,after-sales service capabilities, etc.,to consider the manufacturer’s heat exchanger product use The life expectancy, the maintenance period and difficulty of the product life cycle, the cost of maintenance and spare parts during the life of the product, etc., adopt the correct measurement standard--the comprehensive average cost of the product life cycle as an important evaluation index to measure the advantages and disadvantages of the heat exchanger products. Is the right thing to do.
Miscellaneous 5: Holding the design plan and drawings of the manufacturer of the heat exchanger, or the product requires the B heat exchanger manufacturer to quote. For the purpose of price comparison, many customers will ask for the price of a heat exchanger manufacturer's product design, drawings, product data or even just a product model. The size and heat exchange area of the products provided by the unit must be identical to those of other units. In fact, due to the production and marketing positioning of each heat exchanger manufacturer, product plate type source, product specification performance, product naming rules, design selection.