Excellent durability of sintered mesh screens for high temperature applications

Sintered metal media have shown excellent particle removal efficiency, consistent filtration performance, suitable backwash capability, and long on-stream service. The sintered mesh filters offer particulate hold efficiency of 99.9% using surface or depth media. Considering the filtration efficiency, other essential factors are corrosion resistance, mechanical strength, cake release and prolong on-stream service life. These factors are critical to conducting successful, economical operations. The service life of such filter systems will be based on mesh’s particulate holding capacity and related pressure drop. This accumulating cake can be regularly removed by using a blowback cycle. The suitability of the blowback cycle and filter pressure drop recovery is a major function of the properties of the accumulating particles in the cake and filter media.

Sintered metal mesh can be considered as semi-permanent media. A benefit of the metallic filters is their welability to hardware to acquire strong sealed joints. The media can withstand pressure spikes without any evidence of media migration. The inherent toughness of the metal filters fives continuous, back pulsed service for long periods. For elevated temperature applications, other factors considered are creep-fatigue interactions and high temperature corrosion mechanisms. Filters with sintered mesh are economical that need minimal operator intervention and occasional maintenance.

Filters with permanent structure of sintered mesh can be cleaned in numerous ways without media migration. The selection of suitable corrosion resistant alloy for particle elimination assures liquid purity or gas separation. In-situ cleaning of process filters is performed by using liquid or gas backwash. Chemical cleaning with compatible materials or ultrasonic cleaning in a detergent solution will eliminate insoluble contaminants from inside the filter media. Sintered mesh screens are made using variety of corrosion resistant alloys such as Stainless steel 316l, 304l, Hastelloy B, C22, C276, Inconel 600, 625, Monel 400 and Nickel 200.

Filters equipped with sintered mesh screens can serve up to 950oC depending on alloy type and service conditions. The sintered metal elements can be supplied to withstand differential pressures above 210 bar. These elements create permanent media to deal with pressure spikes without media migration. Single or multi-layered construction are used with every layer consisted of widely different diameter fibers to attain required performance such as pressure drop, filtration efficiency, particle loading capacity and media strength. Sintered multi-layered mesh screens have a gradual design to hold dirt particles better and hence providing longer life. The ultimate filter rating is determined by the weight per used layer, the fiber composition of the layer and combination of innumerable layers. The availability of a high porous structure provides higher permeability and hence minimum pressure drop.

The characteristics of metal fiber filters, produced from different metal alloys, for gas filtration applications enable the use in extensive conditions such as high temperature, high pressure and corrosive conditions. The major advantages of sintered metal filters are: strength, high pressure and temperature capabilities, high thermal shock resistance, corrosion resistance, cleanability and prolong service life.

How insect screens keep bugs away in little to large space

Heanjia’s insect screens turn each room into an insect-free place- efficient, beautiful and convenient. The screen solutions are fabricated for both inside and outside areas. The screens are made to measure and can be installed on all skylights and light wells. The insect screens for fixed, sliding frames or blinds are made using the high grade materials providing the best protection for several years.

Advanced technology and right size of the products provide you great comfort. A house free of insects is specifically important for those suffering from allergies, because a sting may transfer germs causing an allergic reaction.

The unobtrusive insect screen elements need a nominal space and can be configured into your facade or living area. The delicate insect screen allows adequate flow of light and air. Particularly sturdy specifications are made on special request for example for pets sharpening their claws on insect screens.

Installation of insect screens is quite simple. Durable frames provide the required sturdiness. Sliding frames are directed from underneath for smooth operation. You can also easily retrofit the insect screens if needed without drilling.

On hot evenings in summer, it shows its actual potential, the suitable solutions from insect screen supplier keep bugs, mosquitoes, moths and midges away from your house. We offer tailored solutions for windows, balcony or doors, to install inside or outside. Retrofitting is also feasible for all versions.

Our insect screens perfectly fit in various designs of windows and doors such as:

·         Windows for airing- fixed frames

·         Frequently used windows and doors for swivel frames, sliding frames, roller blinds and pleated insect

·         Large door and window areas

·         Sloping roods and skylights

Usually windows are opened only for airing the room and need full solutions for protection against insects. Our insect screens provide fresh, insect-free air for your place. They are durable, economical and suitable for customization. If you want to keep bugs away from your house, you should choose a model with a brush sealing strip, closing even the smallest gap.

Benefits of using insect screens

·         For different windows in fact with sloping window sills

·         High durability

·         Economical solution for windows

·         Ready to be customized

·         Rectangular and circular shapes are available

Insects prefer rapidly used patio doors, because they do not shut immediately. Our insect screens prevent these unnecessary species. They perform reliably and can be integrated easily in the existing panel. So open your doors fully in summer while prevent annoying insects. Heanjia insect screen can manage both. The operation is pretty easy. We even offer a solution for narrow balconies. They are ideal for large and small areas. The screens offer flexible operation from inside or outside providing easy accessibility to handle. They can be used anywhere doors to conservatories, patios, balconies or glazed facade sections, single or double wing windows and doors.

Insect screens effectively protect people from insects even in small balconies and patios without space for frame. They provide excellent protection even with little space.

Effect of heat treatments on corrosion resistance of Inconel 718

Inconel 718 has effective resistance to carbon dioxide, hydrogen sulfide and acetic acid containing environments. Corrosion rates of below 1 mil per year occurred to high temperatures. Only with acid, oxygen or elemental sulfur corrodes Inconel 718. So, the pitting corrosion resistance is counted as the most vigorous environment occurred in the industry. There are several alloys considered to be corrosion resistant in the most production conditions. Inconel 718 has pitting corrosion resistance similar to duplex stainless steels. Alloys like SS 304 are slightly used due to their corrosion resistance. Inconel 719 applications are usually not limited to corrosion resistance.

The general corrosion resistance and pitting corrosionresistance of Inconel 718 are influenced by heat processing. The effect of aging temperature on the pitting corrosion resistance in the yellow death solution. Increase in pitting temperature shows enhanced corrosion resistance. The reproducibility of this test is about 5 C. Heat treatments to 1350oF do not create a detrimental effect on the pitting temperature in the yellow death solution. Although, heat processing at 1450oF affects the pitting corrosion resistance. The loss in pitting resistance can be added to the precipitation of carbides and to segregation of alloying elements during precipitation hardening treatments. It is found that higher annealing temperatures are detrimental to pitting corrosion resistance of Inconel 718. Although, except in the extreme cases, pitting corrosion resistance is not a limiting characteristic, although in the 1450oF heat processing conditions evaluated. Both localized corrosion and generalized corrosion resistance reduce with increase in temperature of aging treatments.

Inconel 718 offers adequate resistance to corrosion in acidizing conditions. Relative corrosion rates of alloys in 10% boiling hydrochloric acid is evaluated. This acid is unpreventable and causes highest corrosion rates anticipated for short-term exposures. Inconel 718 corrodes at 4 mils per day, in fact in the uninhibited acid. The corrosion resistance is comparable to alloys 825 that are a likely combination with Inconel 718 in the various severe completions. From a practical perspective, the corrosion resistance in oil field acidizing environments is sufficient, particularly as these conditions will comprise of corrosion preventors to further decrease the corrosion rates. The influence of heat processing on corrosion resistance of alloy 718 in hydrochloric acid is not evaluated. The effects of H2S on acidizing have also not been tested.

Inconel 718 is sensitive to hydrogen embrittlement particularly in the high strength heat processed conditions. Although various studies of hydrogen embrittlement have been done with high strength materials. So, the results from study with these high strength materials for the aerospace industry may not be relevant in describing the chance of failure in oil field applications. Although the effects of heat processing or other environmental factors may be relevant to oil industry applications. The effect of heat processing on the hydrogen embrittlement resistance in the high pressure hydrogen at room temperature is evaluated. It is found that high temperature aging processing about 1400oF enhance the resistance to hydrogen embrittlement of Inconel 718.

Stainless steels-The core application material of industries

Iron and iron alloy such as steel are poor materials as they rust in air, corrode in acids and scale in furnace conditions. There is a group of iron-base alloys, the iron-chromium-nickel alloys are called as stainless steels, that do not rust in sea water, are resistant to concentrated acids and that do not scale at temperatures up to 1100oC.

Good mechanical properties and manufacturing features give the stainless steels their raison and make them vital tool for the designer. The usage of stainless steel is nominal as compared to carbon steels that attain a steady growth, unlike to the constructional steels.

Stainless steels as a family is certainly more non-uniform than the constructional steels and their properties are in diverse cases relatively unfamiliar to the designer. In some ways, the stainless steels are an undetermined world however to take the benefit of these materials will need a better understanding of their basic properties.

Use of stainless steel

Steel is the major industrial constructional material. Dominant product form for stainless steels is cold rolled sheet. The applications are dominated by major sectors: consumer products, equipment for oil and gas plants, chemical process plants, food and beverage industry.

The commonly used stainless steel grades are SS 304 and SS 304l that form more than 50% of the global production of stainless steel. In order to receive a perspective of the development of stainless steels, it is right to consider the background.

Alloying elements have a specific influence on the properties of the steel. It is the combined influence of the allying elements, to some level, the contaminants that determine the feature of a specific steel grade. The influence of alloying elements on the important material properties is evaluated.

The most important feature of stainless steel is their corrosion resistance. The reason for the good corrosion resistance of stainless steels is that they develop a thin, invisible surface film in oxidizing conditions.

Aqueous corrosion refers to corrosion in liquids or moist conditions at temperatures up to 300oC, often in water-based conditions. The corrosion process is electrochemical and needs the presence of an electrolyte in the form of a liquid.

High temperature corrosion allows corrosion in hot gases at temperatures up to 1300oC.

Stainless steels are significantly different from carbon steels in some respects. There are also significant differences between the different categories of stainless steels.  Heat conductivity for stainless steels is usually lower than for carbons steels and reduces with increasing alloying level for every stainless steel category.

Austenitic steels are featured by supreme corrosion resistance, good toughness and excellent weldability, they are the most common stainless steels. The properties of Hastelloy wire grades include resistance to general corrosion, pitting and crevice corrosion and stress corrosion cracking. Low carbon grades attain supreme resistance to intergranular corrosion and as a result higher alloyed steels are only available with low carbon concentrations. Austenitic stainless steels are used in all types of applications and industries. Common areas include piping systems, heat exchangers, tanks and process vessels for food, chemical, pharmaceutical, pulp and paper and other process plants.

Durable sintered mesh elements for filter cartridges and methods to clean them

Filter cartridges made from sintered wire mesh are suitable for applications that need a robust filter cartridge resistant to extreme chemicals. They are made in varied sizes to suit industry standard filter structures even also in diverse non-standard sizes and specifications. The screens made from 316L grade stainless steel and configured without using resins or adhesives.

Sintered stainless steel mesh filter cartridges use sintered mesh structure for filter configuration that combines filter efficiency with strength. Standard mesh construction would consist of an external protective layer, an internal main filter layer, drainage layer and eventually two strengthening layers to offer strength. The fiver mesh layers are sintered to develop a single sheet of filter media.

The mesh cartridges can be in cylindrical or pleated form and in different lengths, diameters and endcap configurations.

How to clean sintered mesh filter cartridges

Reverse Flow: When much of contamination is larger than the pore size of the filter media, reverse flow of liquid or gas through the element will often be sufficient for cleaning. Usually, a flow of minimum two times the forward flow gives complete cleaning.

Ultrasonic cleaning: Surface contamination can be eliminated by ultrasonic cleaning in bath containing detergent, immersed particulate may not be eliminated.

Chemical cleaning: Different chemicals are used to dissolve the contaminant or process fluid in case of hardening on contact with air.

Heanjia can provide you with a wide set of sintered mesh elements used in filtration. It is crucial in the development of synthetic fibers and we can eventually enhance and innovate your conventional filtration. The metal to metal gaskets used in the polymer industry by the diversity refers to the production and quality of our tools. The screens can be made in any shape or dimensions available in different alloys.

We offer a solution allowing a reduced consumption of filters and an enhanced quality of filtered polymer. We can offer a wide range of material to be used as filling sands in the stainless steel, Inconel, aluminium and other high performance materials.

We are specialized in the development and production of metal filtration solutions. We offer filter elements for industrial gas filtration, depending on the special benefits of metal fiber media. Our filter elements are fit for use in high temperature, corrosive chemical and petrochemical process, for process filtration and exhaust gases. These elements are the perfect solution for applications demanding high mechanical stability, long service life, low pressure drop, easy cleaning and chemical and heat resistant are needed.

Filter materials are used for temperature resistance up to 1000oC. Filtration of elements in applications where small dust loads are separated from a gas stream. The contaminants are held in multiple layer structure of the filter medium. Advantage of our depth filter systems that combine high temperature and corrosion resistance with high dirt retaining capacity and outstanding off-line cleaning feasibilities, the excellent solution for your applications. 

How the use of arc spray coatings improve corrosion protection of a component

Coatings are developed to offer protection from corrosion and erosion to secure the material from chemical and physical interaction with its environment. Corrosion and wear issues are of great relevance in diverse industrial applications as they result in the degradation and eventual failure of components and systems in the processing and manufacturing industries and in the service life of various components. Different technologies are used to deposit the suitable surface protection to provide protection under specific conditions. They are often distinguished by coating thickness.

Most thermal coating processes are used at atmospheric pressure in air, except plasma spraying, usually served in soft vacuum. Plasma spraying can be performed in an inert condition or vacuum and cold spray is usually performed at atmospheric pressure however in a controlled condition chamber to collect reuse the spray gas due to the large gas flow rates required.

Extreme uses of arc spray wire are now in culture against wear and corrosion as well as heat and also for functional purpose. The choice of coating process is firmly based on the required coating properties for the application and coating cost. Coating characteristics are determined by the coating material and the form in which it is used, as well as the setoff parameters used to conduct the coating process. Thermal spray coatings are usually featured by a lamellar structure and the real contact between the splats and substrate or the earlier deposited layers determine to a large level of the coating properties like heat conductivity, Young modulus etc.

The real contact area ranges between 20-60% of the coating surface parallel to the substrate. It increases with impact speed of particles. Therefore the coating density increases with increase from flame, wire arc, plasma and gun spraying and thereafter re-fused.

The variety of corrosions particularly for coatings can be categorized as general corrosion, related to 30% failure, where the average rate of corrosion on the surface is uniform and localized corrosion, about 70% of failures. The galvanic corrosion occurs when two different metals are in contact with each other in a conductive solution, the more anodic metal is attacked where each other in a conductive solution, the more anodic metal is attacked, while the more cathodic one is uninfluenced. The electrolyte plays a significant role, and the relative surface contact area, small anodic to cathodic area ratio refers to severity of anodic metal corrosion.

The corrosion can also be intergranular as well as transgranular when cracking occurs. The coating material and is microstructure plays a crucial role in this type of corrosion. The coatings provide protection from corrosion, sacrificial coatings, thicker coatings offer longer protection.

Corrosive wear occurs when the influence of corrosion and wear are combined, resulting into faster failure of material surface. A surface that is oxidized can be mechanically weakened and can wear at a higher rate. Stress corrosion failure results from the combined influence of stress and corrosion. With thermal spray coatings, such types of metallic failures can be significantly reduced. 

Performance of Nickel based super alloys in industrial chloride conditions

The commonly accepted application of commercially pure nickel is to handle the highly concentrated solutions. Nickel shows lower corrosion rates in hot caustic solutions than alloyed nickel as alloying elements like chromium and molybdenum dissolve commonly from alloy in hot caustic solutions. Nickel can also withstand cold reducing acids due to slow discharge of hydrogen on its surface. Hot reducing acids and oxidizing acids quickly attack pure nickel. 

The key application of Monel bars is in handling pure hydrofluoric acid. Although if oxidants like oxygen exist in hydrofluoric acid, Monel alloys may experience intergranular attack. Monel alloys are slightly more resistant to general corrosion than Nickel 200 in hot reducing and oxidizing acids like sulfuric acid and nitric acid. Ni-Mo alloys usually called as Hastelloy B type alloys, are made to withstand reducing HCl at all concentration and temperature limits. As costlier materials like Hastelloy alloys are also used in handling other corrosive reducing conditions like dilute sulfuric, acetic, formic and hydrofluoric acids. Alloy B2 has the minimum corrosion rate in boiling 10% sulfuric acid. Although Hastelloy alloys show poor performance in oxidizing acids, for instance, in hydrochloric acid contaminated with ferric ions.

There are several commercially available Ni-Cr-Mo alloys. They are derived from original C alloy, the advanced grade is Hastelloy C2000. Although the more common grade in industrial applications is Hastelloy C276. NiCrMo alloys are the most versatile nickel alloys as they comprise of molybdenum for protection against corrosion under reducing conditions and chromium that secures the component from corrosion in oxidizing conditions.

Hastelloy C276 has nominal corrosion rates in reducing and oxidizing conditions. One of the major applications of NiCrMo alloys is in the presence of hot chloride containing solutions. In these environments, most of steel grades receive crevice and pitting corrosion as well as stress corrosion cracking. Although NiCrMO alloys are extremely resistant it is not immune to chloride induced corrosion in major industrial applications.

Nickel based corrosion resistant alloys are NiCrFe alloys. They also contain smaller magnitudes or molybdenum and copper as in Incoloy 825. Nickel-Chromium-Iron alloys are usually less resistant to corrosion as compare to Nickel-Chromium-Molybdenum alloys, although they could be less costly and hence find a great range of industrial applications where the application of stainless steels is limited. The corrosion rate of Inconel 600 in sulfuric acid is higher than corrosion rate of Incoloy 825 as grade 825 contains nominal magnitudes of molybdenum and copper that are advantageous alloying elements for resistance to sulfuric acid. Incoloy 825 has nominal corrosion rate in nitric acid as it comprises of larger magnitudes of chromium. The common applications of Ni-Cr-Fe-Mo alloys like Hastelloy G30 is in the industrial development of phosphoric acid and in highly oxidizing conditions like nitric acid.

Cold processed Nickel 200 is resistant to cracking in NaCl and in chloride concentration of CaCl2 and MgCl2 at 121oC, 149oC, 177oC, 204oC and 232oC.