Chemical pump material selection

All along, corrosion is one of the most troublesome hazards of chemical equipment, a slight carelessness, ranging from damage to equipment, heavy cause accidents and even lead to disaster. According to the statistics, about 60% of the destruction of chemical equipment is caused by corrosion. Therefore, the selection of chemical pumps should first pay attention to the scientific material selection. There is often a misunderstanding that stainless steel is a "universal material," no matter what the media and environmental conditions are held stainless steel pump, which is very dangerous. The following for some common chemical media to talk about the selection of the main points: 1. Sulfuric acid as a strong corrosive medium, sulfuric acid is a very broad use of important industrial raw materials. Different concentrations and temperatures of sulfuric acid on the corrosion of materials vary greatly, for the concentration of more than 80%, the temperature is less than 80 â„ƒ of concentrated sulfuric acid, carbon steel and cast iron has good corrosion resistance, but it is not suitable for high-speed flow of sulfuric acid, Not suitable for pump valve material; common stainless steel such as 304 (0Cr18Ni9), 316 (0Cr18Ni12Mo2Ti) sulfuric acid medium is also limited use. Therefore, the delivery of sulfuric acid pump valve usually adopts high silicon cast iron (casting and processing difficult), high alloy stainless steel (20 alloy) manufacturing. Fluoroplastic has good resistance to sulfuric acid, the use of fluorine pump (F46) is a more economical choice. Company products are: IHF fluoride plastic chemical pump, PF (FS) strong corrosion-resistant centrifugal pumps, CQB-F Fluorine plastic magnetic pump. 2. Hydrochloric acid solution Most of the metal materials are not resistant to hydrochloric acid corrosion (including a variety of stainless steel), molybdenum high ferrosilicon can only be used for 50 â„ƒ, 30% hydrochloric acid. In contrast to metallic materials, the vast majority of non-metallic materials have good corrosion resistance to hydrochloric acid, so lined rubber pumps and plastic pumps (such as polypropylene, fluoroplastic, etc.) is the best choice for the delivery of hydrochloric acid. Company products are: IHF fluoride plastic chemical pump, PF (FS) strong corrosion-resistant centrifugal pumps, CQ polypropylene magnetic pump (or fluorine plastic magnetic pump). 3. Nitric acid Most metals are mostly corrosive in nitric acid corrosion damage, stainless steel is the most widely used nitric acid-resistant materials, all concentrations of nitric acid at room temperature have good corrosion resistance, it is worth mentioning that the molybdenum-containing stainless steel (such as 316,316 L) corrosion resistance to nitric acid is not only not superior to ordinary stainless steel (such as 304,321), and sometimes even worse. For high temperature nitric acid, usually titanium and titanium alloy materials. The company applies products: DFL (W) H chemical pump, DFL (W) PH shielding chemical pump, DFCZ process pump, DFLZP self-absorption chemical pump, IH chemical pump, CQB magnetic pump, 4. Acetic acid It is one of the most corrosive substances in organic acids. Ordinary steel will be seriously corroded in all concentrations and temperatures of acetic acid. Stainless steel is an excellent acetic acid-resistant material. Molybdenum-containing 316 stainless steel is also suitable for high temperature and Dilute acetic acid steam. For high temperature and high concentration of acetic acid or other corrosive media and other harsh requirements, the choice of high alloy stainless steel pump or fluorine plastic pump. 5. Alkali (sodium hydroxide) steel is widely used in sodium hydroxide solution below 80 â„ƒ, 30% concentration, there are many factories at 100 â„ƒ, 75% below the ordinary steel is still used, although the corrosion increases, but the economy is good . Ordinary stainless steel lye corrosion resistance compared with cast iron has no obvious advantages, as long as the medium allows a small amount of iron mixed with stainless steel is not recommended. For high temperature alkaline use of titanium and titanium alloy or high alloy stainless steel. The company generally cast iron pump can be used for low temperature lye concentration, special requirements can be used when all kinds of stainless steel pump or fluorine plastic pump. 6. Ammonia (ammonia hydroxide) Most metals and non-metals in liquid ammonia and ammonia (ammonia hydroxide) corrosion are minor, only copper and copper alloy should not be used. Most of the company's products for ammonia and ammonia transport. 7. Saline (seawater) Common steel corrosion rate in sodium chloride solution and seawater, salt water is not too high, the general shall be used paint protection; various types of stainless steel also have a low uniform corrosion rate, but may be due to chloride ions caused by the local Corrosion, usually 316 stainless steel is better. Various types of chemical companies have 316 material pump configuration. 8. alcohols, ketones, esters, ethers Common alcohol mediums are methanol, ethanol, ethylene glycol, propanol, ketones have acetone, butanone and so on, the ester medium has a variety of methyl esters, Ethyl ether, ethers medium ether, ether, butyl ether, they are basically non-corrosive, common materials are applicable, the specific selection should also be based on the media properties and related requirements to make a reasonable choice. It is also noteworthy that ketones, esters, ethers are soluble in a wide variety of rubbers and avoid mistakes when selecting sealing materials. There are many other media can not be introduced in this one, in short, should not be arbitrary and blind in the selection, the more should refer to relevant information or learn from the mature experience.Cooling the transmission of high temperature medium on the pump structure, materials and auxiliary systems put forward more High requirements, the following talk about the different temperature changes on the cooling requirements and the company applies to the pump: 1. For temperatures below 120 â„ƒ medium, usually do not set a special cooling system, use more of their own medium to lubricate and cool. Such as IHG, ISWH chemical pump, PHG shielding chemical pump (more than 90 â„ƒ shielded motor protection level should be used H-class); and CZ common type and IH chemical pump due to the suspension structure allows the maximum temperature reached 140 â„ƒ ~ 160 â„ƒ; IHF lined with fluorine pump up to a maximum temperature of 200 â„ƒ; only CQB ordinary magnetic pump temperature does not exceed 100 â„ƒ. It is worth mentioning that for the easy-to-crystallize or media containing particles should be equipped with a sealing surface flushing pipe (design have left interface). 2. For media above 120 Â° C and within 300 Â° C, a cooling chamber is normally to be provided on the pump cover and the seal chamber is also to be filled with coolant (to be fitted with a double-ended mechanical seal). When coolant is not allowed to penetrate the medium , It should be taken after the cooling medium itself access (through a simple heat exchanger). The company has CZ-based chemical process pump, GRG high temperature pipeline pump and LQRY hot water circulating pump (under development) for selection, the other CQB-G high temperature magnetic pump can be used within 280 â„ƒ high temperature medium. 3 for more than 300 â„ƒ high temperature medium, not only need to cool the pump head part, the suspension bearing chamber should also be equipped with cooling system, the pump structure is generally the central support form, the mechanical seal is best to use metal bellows type, but the high price The price is more than 10 times the ordinary mechanical seal). At present the company only 2CY \ LQRY centrifugal oil pump temperature can reach 420 â„ƒ (under development).

Safety Washer DIN 9250VS

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