Pvdf nozzle material for food, chemical etching, and electronic industries
PVDF Plastics Material for Nozzle Is improper nozzle material costing your time and money?PVDF nozzle material for food, chemical etching and electronic industries
Key Issues Nozzles are mechanical devices that are used to control the 3) Exposure to high temperature : Melting or fluid flow characteristics when they enter or leave an softening of nozzle material establishes maximum enclosed pipe or chamber, through an orifice. The various temperature limits. However, these limits must be fluid flow characteristics that need to be controlled are mass reduced when corrosion, erosion, oxidation or and rate of fluid flow, direction, shape, pressure and the chemical attack are also present in the given speed of the fluid. Nozzle are also used for dispensing application various media such as powder, steam, abrasives, adhesive, 4) Caking/ bearding : build‐up of material on the water chemical, coolants, coating, ink, lubricants. inside, on the outer edges or near the orifice is They may look simple enough, but spray nozzles are highly caused by liquid evaporation. A layer of dried engineered precision components that can wear over time or solids remains and obstructs the orifice or internal suffer damage during normal operations or even cleaning. flow passages. There are several factors to influence or shorten the nozzle 5) Clogging : unwanted solid particles can block the operating life, sometimes more than one at the same time : inside of the orifice. Flow is restricted and spray 1) Erosion/ Wear : Nozzle wear is indicated by an increase in pattern uniformity disturbed. nozzle capacity and by a change in the spray pattern, in which 6) Accidental damage : damage to a nozzle orifice the distribution (uniformity of spray pattern) deteriorates and can occur if a spray nozzle is dropped or scratched increases drop size. Choice of a wear resistant material of during installation, operation or cleaning construction increases nozzle life. Because many single fluid 7) Improper re‐assembly : some spray nozzles nozzles are used to meter flows, worn nozzles result in require careful re‐assembly after cleaning to excessive liquid usage. ensure that internal components, such as gasket, 2) Corrosion : spray nozzle material can break down due to o‐rings and valves, are properly aligned. Improper the chemical properties of the sprayed material or the re‐assembly causes leaking and inefficient spray environtment. The effect is similar to that caused by erosion performance. and wear, with possible additional damage to the outside surfaces of the spray nozzle. Corrosion is material related and caused by chemical attack. There is a very wide range of materials from which nozzle can be made and the proper selection of the nozzle material will minimise problems.
Selecting Material Improved reliability, proper performance and maximum wear life of a spray nozzle often begin with the correct material selection. Corrosion and erosion caused by abrasive wear are the most common factors that could lead to degradation of a nozzle’s performance. It is important to select the right nozzle material depending on the environmental conditions of the given process. Spray nozzles are generally made of such materials as bronze, stainless steel, or plastic. Brass (Bronze) is the easiest material for nozzle manufacturers to work with and is a common material, but bronze nozzles have insufficient resistance to abrasion at middle/high pressure, and limited resistance to corrosion by corrosive chemicals. Due to its relatively high abrasion and corrosion resistance, stainless steel is widely employed in nozzle manufacture. When the liquid to be sprayed or the surrounding atmosphere is corrosive however, spray nozzles made of SUS316 or SUS31L stainless steel, both of which have more resistance to corrosion, are more suitable. Relatively few types of spray nozzles are manufactured from plastic. Plastic nozzles are useful for spraying chemicals that corrode metal nozzles too quickly. Unlike metal, plastic materials do not display corrosion rates. That is the corrosion of plastic materials is dependent totally on the material’s chemical resistance rather than an oxide layer, so the material is either completely resistant to a chemical or it deteriorates. Thermoplastics deteriorates is indicated by material softening, discoloration, charring, embrittlement, stress cracking, swelling, dissolving and other effects. LEFT: Stainless steel full cone nozzle. RIGHT: same stainless steel and bronze nozzle PVDF plastic nozzle after spraying with limestone slurry. The nozzle erosion and corrosion occurred in less than 2 weeks, demonstrating the need for choosing the correct nozzle material to suit the conditions.
Wear Test COMPARATIVE WEAR TEST Test Medium : 2.5 % kaolin in water Ceramic : Highly resistant to abrasive and provides superior wear resistance in abrasive applications and high pressure. Ceramics have excellent corrosion resistance except in very high pH environments. Polyacetal POM (Polyoxymethylen) : Provide good resistance to alkalis, susceptible to high concentrated acids. Can be used in temperature +90 °C exhibits a high thermal stability and high resistance to hydrolysis. POM shows good sliding properties and high resistance to wear and tear because of the strength and smooth surface. There is a very low risk of stress cracks. Polyvinyldene fluoride (PVDF) : Excellent resistance to strong acid and alkalis, good resistance to wear, resist many reagents and high temperatures (up to 130°C), susceptible to high temperature above water boiling in combination with concentrated sulphuric and nitric acids. Preferred in industrial spraying applications. Stainless steel : Good resistance to chemicals and provide average wear resistance Brass (bronze) : Average resistance to most chemistry and poor wear resistance, susceptible to corrosion especially with fertilisers PEEK : is used to replace metals in harsh environments. This highest performance engineered thermoplastic offers excellent resistance to wear, chemicals, fatigue and high temperatures up to 320°F (160°C).
Application Most nozzle are constructed of stainless steel, but PVDF Nozzle for Etching and Electronic Industry some are made of plastic material such as POM, PVDF nozzles are especially suited to the spraying of PVDF, PEEK. acids during etching operations. And their high thermal PVDF Nozzles PVDF (polyvinyldene fluoride), the stability makes them ideal for high temperature durable yet economical fluoroplastic that stands up stripping operations. For spraying corrosive fluids or for to wear, heat, and corrosion. operation in corrosive environtments. PCB (printed PVDF Nozzle for Food Industry circuoit board) manufacturers are looking for nozzles to In general, foods are not corrosive, but consumable increase product yield. Nozzle made from PVDF material foods like sauces and fruits can have pH ranges offer consistent spray patterns along with superior between 2.0 and 3.5, this can be very aggressive chemical resistance, capable of effectively spraying a environment over time. PVDF plastics components variety of chloride, acid, basses, oxidizing agent and are often machined and used in the processing of ammonia base etchants, these chemical resistance cranberry, hot sauces, alcoholic beverages, lime nozzles can withstand temperatures up to 300 °F at 100 juices and a few other relatively common foods. The psi (149 °C at 7 bar). abrasion resistance of PVDF and its ability to be sterilized with various chemicals and steam also adds to the attractiveness of this material for food, dairy and beverage applications. PVDF is an extremely pure polymer, physiologically non toxic, and meets the european directive 90/128/EEC relating plastic material to contact with foodstuffs. It is particular suitable for high purity applications handling hot and cold water in the semiconductor, and pharmaceuticals industries.
Conclusion PVDF is an outstanding choice as a nozzle PVDF PROPERTIES DATA SHEET material for many reasons: Structure : Crystalline Chemical resistance Specific density : 1.77 PVDF is typically resistant to: most acids salts and Water absorption rate (%): 0.03 weak bases, halogens and halogenated solvents, alcohols, oxidants, De‐ionized water, UV and nuclear Elongation at break (%): 50 radiation. Tensile strength (psi): 5.800 Temperature range Compression strength (psi): 10.000 PVDF can be used at temperatures as high as 285° F Flexural strength (psi): 7.800 (140°C) depending on the chemical environment Flexural modulus (psi): 260.000 and operating pressures of the system. Like most Impact (Izod ft. lbs/in): 6.6 fluoropolymers PVDF is inherently flame retardant. Hardness: R95 Abrasion resistance PVDF is one of the most abrasion resistant Deflection temperature (deg. F) fluoropolymers. In abrasion tests PVDF ranks with ‐ @ 66 psi: 300 (150 deg.C) the best plastics and in most nozzle applications it ‐ @ 264 psi: 190 (90 deg. C) will outlast many metals, PVC and PTFE. Utilization temperature (deg. F) Mechanical strength ‐ min: ‐40 (‐30 deg.C) PVDF is one of the most rigid fluoropolymers. ‐ max: 310 (150 deg. C) PVDFs exceptional tensile strength allows nozzle Melting point (deg. F): 340 (170 deg. C) construction without the thick sections normally associated with plastics, while allowing operating Coefficient of expansion: 0.000022 pressures normally available only with metallic Arc resistance : 60 materials. Dielectrical strength (kV/mm): 22 FDA acceptance UV resistance : Good PVDF is accepted by the FDA for use in a broad Chemical resistance : Excellent range of food and pharmaceutical applications where stainless steel was once the only choice.
THANK YOU www.sugison.comnozzle for candy filler PT YUPI INDONESIAmaterial from pvdf (polyvinyldenfluoride) www.grahamika.indonetwork.co.idmachining by PT. Maxima Sukses