November 04, 2020
Graphite sulfuric acid diluter can be used directly
Cracking and transparency. C-276 is expensive but has good heat exchange effect
and long use time. The tube side is 316L stainless steel, the tube shell is
ordinary carbon steel, the tube side uses a mixture of sulfuric acid and nitric
acid, and the shell side uses cooling water, which is quite good.Question: What
material is the best choice for the sulfuric acid and acetic acid resistant
materials of the heat exchanger tubes? Graphite and fluoroplastic
materials can be used. The material resistant to sulfuric acid and
acetic acid is preferably Hastelloy. 316L ptfe
coated fiberglass adhesive tape Manufacturers stainless steel is sufficient,
because our company also has such a heat exchanger.
For example, the Alfa Laval
plate heat exchanger widely used in the sulfuric acid industry basically uses
Hastelloy C276, and the boiler flue gas desulfurization tower uses 316L, which
is corrosive. It should not be difficult to generalize. Possibly, Hastelloy C276
is used in order to avoid dilute acid corrosion; the acetic acid distillation
tower has a certain temperature, 316L may be corroded, and G30 grade Hastelloy
is used, such as Jiangsu Thorpe Group.
Graphite heat exchanger can be
used. Therefore, it is recommended for key parts. Fluoroplastic heat exchanger
is suitable for nitric acid, hydrochloric acid, sulfuric acid, acetic acid,
phosphoric acid, hydrofluoric acid, aqua regia, chromic acid, organic acid,
ammonium bifluoride, caustic soda, potassium hydride, chlorine (dry) chlorine
(gas-liquid), inorganic Heating, cooling, evaporation, concentration and
crushing of any solution in salt and electroplating surface treatment. Stainless
steel is fine for acetic acid. If it is concentrated sulfuric acid dilution
cooling, graphite sulfuric acid diluter can be used directly, which can dilute
sulfuric acid and cool it to output below 45 degrees. For high-concentration
sulfuric acid heat exchangers, the best is Kazakhstan Alloy (C-276).
The acetic acid resistant material of the heat exchanger tube of the heat
exchanger is best to use titanium or zirconium, but the production cost is
higher. Answer 7: I think it can be based on the operating temperature and
pressure of the heat exchanger, the temperature difference between the inside
and outside of the heat exchange tube, and the nature of the fluid (what
substance and concentration), according to the relevant standards, considering
the material cost, processing cost, and service life, and comprehensive
consideration Select materials. The performance of fluoroplastic heat exchanger:
The heat exchanger material made of PFA, FEP, PVDF pipes is more excellent than
polytetrafluoroethylene (PTFE) heat exchanger material, and has higher thermal
stability, flexibility and resistance.
First of all, the concentration
and temperature of the acid must be clarified, so that the right material can be
selected. Do you require both sulfuric acid and acetic acid resistance
or separate requirements? Also, for sulfuric acid, it depends on the
concentration and temperature
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October 22, 2020
The axial movement of the pump rotor is large
Under the action of fluid pressure and compensating mechanical external elastic
force, the end face relies on the cooperation of the auxiliary seal to keep fit
with the other end, and relatively slide, thereby preventing fluid leakage. The axial movement of the pump rotor is large, the
auxiliary seal and the shaft have a large interference, and the moving ring
cannot move flexibly on the shaft.1mm, and the interference between the
auxiliary seal and the shaft should be moderate.
After the pump is turned over
and the moving and static rings are worn, the displacement cannot be
compensated.While ensuring the radial seal, the movable ring can be
flexibly moved on the shaft after assembly ( Press the moving ring against the
spring to spring back freely).　　 Countermeasures: The above problems can be
corrected according to the maintenance standards. Countermeasures: When
assembling the mechanical seal, the axial movement of the shaft should be less
than . The main positions of the grinding shafts are as follows: moving ring
auxiliary sealing ring, static ring position, A few springs have shaft grinding.
Some have rotted and lost their proper function, resulting in the phenomenon of
shaft grinding.　　
Countermeasures: The height of the lubricating oil surface in
the oil chamber cavity should be higher than the sealing surface of the dynamic
and static rings. Due to the corrosion of the weak acid and weak alkali of the
moving and static ring auxiliary seals, the rubber parts have no elasticity. The
operation of mechanical seals directly affects the normal operation of pumps.
The summary analysis is as follows. The main part of the grinding shaft is a
rubber bellows, and because the upper sealing surface is in a poor lubrication
state, the friction torque between the moving and static rings is greater than
the transmission torque between the rubber bellows and the shaft, and relative
rotation occurs.
When using mechanical seals, various factors of using
mechanical seals should be analyzed, so that the mechanical seals are suitable
for the technical requirements and medium requirements of various pumps and have
sufficient lubrication conditions, so as to ensure long-term and reliable
operation of the seal. Insufficient lubricant on the sealing surface causes
dry friction or roughness on the sealing end surface.The main reasons for
shaft grinding: BIA type double end face mechanical seal, the back pressure
state is a bad working condition, particles and impurities in the medium can
easily enter the sealing surface and cause the seal to fail.
The reason is the
misalignment of the stator and the upper and lower end caps or the imbalance of
the impeller and the main shaft, cavitation or bearing damage (wear), this
situation will shorten the seal life and cause leakage.The rotor vibrates
periodically. It has a pair of end faces perpendicular to the axis of rotation.Shaft grinding phenomenon caused by seal leakage of small submersible pumps The mechanical seal failure of small pumps below 715kW often produces
grinding shafts. Common leakage phenomena The leakage of mechanical seals
accounts for more than 50% of all repaired pumps. A mechanical seal is also
called an end face seal.The mechanical seal itself is a demanding PTFE
coated adhesive tapes precision component, which has high requirements on
design, machining, and assembly quality.
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October 14, 2020
Such bonding is generally solved by bonding or welding
After the problems of bonding and welding are solved, PTFE will surely have more advantages in the field of anti-corrosion. However, because PTFE material itself has extremely high chemical stability and non-stickiness, its bonding and welding are more troublesome, which has always been a major problem in the application of PTFE materials. Introduction to the welding methods of polytetrafluoroethylene (PTFE) With the rapid development of modern industry, the problem of material anti-corrosion has attracted widespread attention from all over the world.
With the advancement of scientific research methods and production processes, new adhesives, bonding processes and welding methods suitable for bonding and welding of PTFE materials will continue to appear. Introduction PTFE fiberglass adhesive tapeto the commonly used bonding methods of polytetrafluoroethylene (PTFE) 2.With the advancement of anti-corrosion technology, anti-corrosion materials are constantly being introduced. Such bonding is generally solved by bonding or welding.
It can be used alone or in combination with other materials, such as combined with stainless steel. However, in specific applications, the problem of mutual bonding between materials is involved, including between PTFE and PTFE and between PTFE and stainless steel. Among them, polytetrafluoroethylene (PTFE) has attracted more and more attention due to its excellent chemical stability, high temperature resistance and chemical corrosion resistance. It is an ideal anti-corrosion material.
It is currently one of the most widely used and best-effect materials in industrial anti-corrosion. In a large number of anti-corrosion production practices, PTFE has been adopted by many enterprises due to its unique properties. Based on experience, we will introduce several commonly used and effective methods of bonding and welding PTFE workpieces.
The latter can not only exert FITE's unique anti-corrosion properties, At the same time, the high strength of stainless steel can be used, which can avoid the shortcomings of low strength of FITE and poor anti-corrosion ability of stainless steel, which plays a good role in promoting strengths and avoiding weaknesses.
After solving the problems of bonding and welding of PTFE, the application of PTFE as an anticorrosive material in industrial production will be more extensive. , Has become one of the indispensable important materials today. Big deed. As a special anti-corrosion material, PTFE mostly appears in the form of workpieces in daily applications
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September 16, 2020
The strength and chemical resistance of the filter media are increased
After impregnation, the strength and chemical resistance of the filter media are
increased, and the air permeability is reduced. PTFE fiber At present, under
some relatively complex high temperature conditions, the service life of pure
PPS or aramid fiber is affected, such as waste incineration, dust removal from
power plants, and cement dust removal. PTFE emulsion is the most used for glass
fiber filter media, because glass fiber has no cohesive force.
PTFE sewing
thread PTFE sewing thread has high strength and good chemical resistance.1. 3.
2. Now many customers use PTFE sewing thread (glass fiber bag, PPS bag, Aramid
bags, P84 bags). % PTFE fiber below. PTFE emulsion PTFE emulsion impregnation is
also a post-treatment process for high-temperature filter media.
PTFE base
fabric The PTFE base cloth is woven from PTFE filaments, and its main function
is to enhance the strength and chemical resistance of the filter bag, and the
purpose is to increase the service life of the filter bag; the combination of
PTFE base cloth + PPS surface layer is widely used in power plant dust removal.
At present, many filter material manufacturers have used automatic sewing
machines, and only PTFE sewing thread is almost endless. PTFE membrane
High-temperature filter materials often add a finishing process in special
working conditions, that is, the filter material is treated with PTFE coating,
the purpose is to resist condensation, easy to clean dust, and corrosion
resistance; currently polyester, glass fiber, PTFE Fusing
Belts Manufacturers PPS, aramid And P84 filter media are both useful.
Customers often add 50% to ensure the service life of more than 3 years.
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September 08, 2020
The material can even have enough conductivity to be used as an antistatic coating
Unique electrical properties of Teflon spraying. In a fairly wide frequency
range, Teflon coatings have high insulation strength, low dielectric constant,
and extremely high surface resistance. Teflon spraying heat resistance Teflon?
Industrial coatings can work continuously under temperature conditions up to
260°C/500°F; under the condition of sufficient ventilation, the short-term use
temperature can reach 315°C/600°F .
Industrial coatings can be used at
low temperatures as low as -270°C/-454°F.html Teflon spray, Teflon spray,.kytfl.Teflon spray non-wetting property Since the
surface coated with Teflon® is both oleophobic and hydrophobic, it will not be
easily wetted. The only two chemicals known to affect Teflon, industrial
coatings are molten alkali metals and highly reactive fluorinating agents.
Cleaning is easier and more thorough—in many cases, these surfaces can be
self-cleaning.
Coating type.20, depending on the
load, sliding speed and the specific Teflon used. Teflon spray chemical
resistance PTFE Coated
Fabric Generally speaking, Teflon is not affected by the chemical
environment. Low temperature stability of Teflon spraying Many industrial Teflon
coatings can withstand harsh extreme temperature conditions without compromising
their physical properties.
Low friction coefficient Teflon? The friction
coefficient of the coating is generally in the range of 0. Through special
technology, the material can even have enough conductivity to be used as an
antistatic coating
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September 03, 2020
A large number of technical personnel retired
In the middle and late 1990s, due to economic benefits, a large number of
technical personnel retired, which affected the in-depth research and
development of fluoroplastics processing. After 40 years of development, the
fluoroplastics processing industry is gradually transitioning from the
production of semi-finished products to the production of auxiliary products in
the automotive, electronics, chemical, machinery, building materials,
environmental protection, textile, and food industries.
Development of
fluoroplastics 2. It has been widely used in aerospace, atomic energy,
electronics, electrical, chemical, machinery, construction, textile,
pharmaceutical and other industries.
The products that have been industrialized
and sold on the market include polytetrafluoroethylene (PTFE), Polyvinylidene
fluoride (PVDF), ethylene-tetrafluoroethylene copolymer (ETFE),
ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyvinyl fluoride (PVF),
tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer There are about 100
brands of more than ten varieties, including PFA,
tetrafluoroethylene-hexafluoropropylene copolymer (also known as
polyperfluoroethylene propylene FEP), and polychlorotrifluoroethylene (PCTFE).
In the 1980s, on this basis, my country's fluoroplastic processing enterprises
(mainly township enterprises) were established, especially in Jiangsu and
Zhejiang provinces, which greatly promoted the growth of my country's
fluoroplastics processing industry. Sector, and increasingly penetrate into
people’s daily lives. In recent years, China's sustained and rapid economic
growth has provided a broad market space for fluoroplastic products.1 Historical
review of fluoroplastic molding process research and product processing in China
The history of the development of the fluoroplastics processing industry in
China is a typical epitome of the Shanghai Plastics Research Institute. S..
It
was the earliest established research institute mainly engaged in the research
of fluoroplastics molding process in China. Some products have replaced imports,
and some A large number of products go to the international market. In the late
decade, a series of process technologies such as compression molding, push
molding, blow molding, injection molding, (spiral) extrusion molding, dipping,
coating, and surface treatment of fluoroplastics have been researched, and
corresponding technologies have been established.
It is difficult to replace
other conventional plastics, so its economic benefits are much higher than
conventional plastics. Although processing is relatively difficult, they have
high thermal stability, low dielectric constant, low moisture absorption, low
flammability, low surface energy, excellent weather resistance and excellent
chemical resistance.
Since Plunkett synthesized polytetrafluoroethylene, the
development, production, processing and application of fluoroplastics have been
greatly developed, so there are many varieties. Since 1938, American scientist
R. Test, test methods, and theoretical basis BBQ grill mat
Manufacturers for the design of molds and non-standard molding equipment.
Fluoroplastics are polymer materials with excellent performance.1 Introduction
Fluoroplastics are an important type of plastics with excellent performance. It
was established in 1958 and was formally established in 1963
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August 27, 2020
The proportion of photons in the total is very small
The proportion of photons in the total is very small, so fluorine materials
have good environmental and weather resistance. Because the stable fluorine
atoms surround the carbon chain, PVDF has good chemical stability and is not
easily corroded by acids, alkalis, strong oxidants and halogens at room
temperature. Because PVDF is soluble in some strong polar solvents and has good
spinnability, it can be used for spinning to prepare hollow fiber membranes.
It
is a polymer material with good film-forming properties, such as
dimethylformamide (DMF) and dimethylacetamide (DMAC) and N-methylpyrrolidone
(NMP) and other polar solvents dissolve.Abstract: Polyvinylidene fluoride
(PVDF) has the advantages of PTFE Coated
Fabric low price, good chemical and thermal stability, and high mechanical
strength. The serious pollution in the separation process restricts the
application of PVDF separation membranes.
The wavelength of photons is between
200-700nm, and the CF bond energy is close to 220nm. Because fluorine atoms have
large electronegativity and small atomic radius, the CF bond length is short,
and the bond energy can reach 50kJ. Polyvinylidene fluoride was first
commercialized in the construction field in 1961.. Keywords: polyvinylidene
fluoride, hydrophilicity, contact angle 1.mol- 1.
The melting point is 170°C,
the thermal decomposition temperature is above 316°C, and it will not decompose
within 2 years of continuous exposure to high temperatures below 150°C. In
recent years, fluoropolymers have been used as a kind of membrane material with
excellent performance, and their research and application in the field of
membrane separation engineering have become a hot topic. However, the
symmetrical distribution of fluorine atoms on the PVDF molecular chain results
in low surface energy and strong hydrophobicity on the surface of the material.
Due to the symmetrical distribution of fluorine atoms, the whole molecule shows
non-polarity, and the surface energy of the polymer is very low, only 25J.
Fluorine atoms replace hydrogen atoms. Introduction to PVDF[1] PVDF is obtained
by suspension polymerization or emulsion polymerization of vinylidene fluoride
monomer CH2=CF2. Therefore, the surface of the membrane material needs to be
hydrophilized and modified. The modification of polyvinylidene fluoride membrane
mainly includes two methods, physical and chemical, and then can be used to test
the contact angle and pure water flux of the membrane to characterize its
hydrophilicity and hydrophobicity.
The entire molecular chain is flexible to
make the polymer have a certain degree of crystallinity, showing outstanding
thermal stability.m-3. The excellent performance of PVDF resin has been widely
proven in the decades of use, and it has been widely used in X-ray lithography,
optical fiber, coatings, etc. From the analysis of PVDF molecular structure, the
whole conforms to the zigzag configuration of the carbon chain of general
polyolefin molecules. Generally, the visible light---ultraviolet light in solar
energy has a destructive effect on organic matter
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August 18, 2020
It has excellent chemical stability
The advantage of PFA is that it has a higher continuous use temperature of
260°C, stronger stiffness and toughness, and is suitable for anti-sticking and
chemical resistance applications under high temperature conditions. (all are the
transliterations of TEFLON). Teflon is divided into four types: PTFE, FEP, PFA, and ETFE.
Teflon
(Teflon spray) coating is a special high-performance coating (paint) that
combines heat resistance, chemical inertness, excellent insulation stability and
low friction, and has comprehensive advantages that other coatings cannot
compete. Because of the pronunciation, it is usually called Teflon, Teflon, and
Teflon.Teflon PFA: PFA (perfluoroalkyl compound) non-stick coating, like FEP,
melts and flows during baking to form a non-porous film.
Teflon FEP: FEP
(Fluorinated Ethylene Propylene Copolymer) non-stick coating melts and flows to
form a non-porous film during baking.Teflon paint (paint), the English name is
TEFLON, is a kind of fluorine paint with polytetrafluoroethylene Toaster Bag
Manufacturers as the matrix resin.
Its
flexible applicability makes it widely used in: cookware, tableware, furniture,
molds, home appliances, automobiles, machinery, medicine, technology and so on.
The maximum use temperature is 200 ℃. It has excellent chemical stability and
excellent non-stick characteristics.　　 Teflon PTFE: PTFE
(polytetrafluoroethylene) non-stick coating can be used continuously at a high
temperature of 260 ℃, the highest use temperature can reach 290-300 ℃, very low
friction coefficient, good wear resistance and excellent chemistry
stability.kytfl.html Teflon coating, Teflon coating.
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