News
Why we choose PVDF valves, pipe fittings and pipes?
Why we choose PVDF valves, pipe fittings and pipes?
There are UPVC, CPVC, PPH, PVDF, FRPP valves, pipe fittings and pipes on the market. Why we choose PVDF material? First we should know the following PVDF characteristic:
What is PVDF Material Characteristic?
Polyvinylidene fluoride, referred to as PVDF, it is a monomer formed by trifluoroethylene, hydrofluoric acid and zinc powder, and after polymerization to generate white crystalline solid.
After hot melt butt welding, the connector shall be fixed in the hot melt butt welding machine, and cooling the connector according to cooling period which specified in the regulations of pressure maintaining and cooling of hot melt butt welding machine. After the cooling, reduce pressure to zero, and then remove the welded pipe/fittings.
What is PVDF Physical Properties ?
|
Item |
Unit |
Standard Value |
Standard |
|
Density |
kg/m³ |
1770～1790 |
ISO 1183 |
|
Vicat |
℃ |
≥165 |
ISO 2507 |
|
Tensile Strength |
MPa |
≥40 |
ISO 6259 |
|
Impact Strength（23 ℃） |
KJ/m² |
≥160 |
ISO 179 |
|
Vertical Retraction Ratio (150 ℃) |
% |
≤2 |
ISO 2505 |
1.Temperature resistance:
PVDF pipe system has good thermal stability, can maintain stable performance in a wide range of temperatures, the highest long-term use of temperature up to 150 ° C or so.
2.Mechanical strength:
Compared with other plastic materials, PVDF vales, pipe fittings and pipes have high tensile strength, impact resistance and abrasion resistance, and can maintain good rigidity and toughness even at low temperatures.
3.Dimensional stability:
PVDF vales, pipe fittings and pipes exhibits a small coefficient of thermal expansion when subjected to heat or cold, so it is able to maintain stable dimensional accuracy.
4.Hardness and rigidity:
high hardness and good rigidity, making the pipe not easy to deform and easy to install.
What is PVDF chemical properties?
1.Chemical corrosion resistance:
PVDF vales, pipe fittings and pipes has high chemical inertness to most acids, alkalis, salts and many organic solvents, which is the ideal pipeline material for conveying corrosive media in the field of chemical industry.
2.Non-adhesion:
smooth surface, not easy to adhere to the material, which can reduce the accumulation of scale and clogging phenomenon in the conveying process.
What is PVDF products connect method?
As same as PPH, PVDF pipe system is bonded by hot melt too, which also can be divided into hot melt socket welding and hot melt butt welding. The specific steps of hot melt socket welding as same as PPH too.
The specific steps of hot melt butt welding of PVDF as same as PPH too, but there are some different on process reference , details as below：
|
Nominal wall thickness/MM |
Aligning |
Heating |
Transfer |
Welding |
|
|
240℃±8℃ Heating component temperature 240℃±8℃ |
|||||
|
Height of the flap on the heated part at the end of
the alignment time (min)
(alignment p=0.01N/mm2)/mm
|
heating time≈10e+40s |
Transfer time（max）/s |
Welding pressure formation time/s |
Cooling time under welding pressure (min) [p(0.10+0.01)N/ mm2 t≈1.2e+2min]/min |
|
|
6.0～10.0 |
0.5～1.0 |
95～140 |
USD 4.00 |
5～7 |
8.5～14 |
|
10.0～15.0 |
1.0～1.3 |
140～190 |
USD 4.00 |
7～9 |
14～19 |
|
15.0～20.0 |
1.3～1.7 |
190～240 |
USD 5.00 |
9～11 |
19～25 |
|
20.0～25.0 |
1.7～2.0 |
240～290 |
USD 5.00 |
11～13 |
25～32 |
Comparison of Characteristic:
The differences of U-PVC, PPH and C-PVC products on working temperature and connect method
|
The differences of U-PVC, PPH and C-PVC products on working temperature and connect method |
|||
|
Materials |
Max working temperature |
Continuous Use Temperature must below |
Connected by |
|
UPVC |
60℃ |
45℃ （0~45℃） |
Cement |
|
PPH |
110℃ |
90℃（0~90℃） |
Hot meld socket welding and butt welding |
|
CPVC |
110℃ |
95℃ （0~95℃） |
Cement |
|
PVDF |
200 ℃ |
150℃ （-30~150℃） |
Hot meld socket welding and butt welding |
Which industry applications for PVDF valves,pipe fittings and pipes?
1. Chemical industry:
Widely used in various chemical processes in the fluid delivery system, such as transporting acid, alkali solutions, oxidants, solvents and other corrosive substances.
2. Semiconductor and electronics industry:
In the clean room environment of ultrapure water delivery system, as well as chemical storage and distribution system as the preferred piping material.
3.Environmental protection engineering:
PVDF vales, pipe fittings and pipes is widely used for its corrosion resistance and bio compatibility in wastewater treatment, seawater desalination, and the pre-treatment and post-treatment stages of reverse osmosis membrane systems.
4. Pharmaceuticals and biotechnology:
In the production process requires strict control of pollution and prevention of microbial breeding occasions, PVDF pipeline because of its high cleanliness, non-toxic and odourless and is used for conveying pure water, pharmaceutical intermediates or other liquids.
5. Energy and nuclear industry:
Due to its radiation resistance and high temperature resistance, it is also used in the cooling water system of some nuclear power plants and other energy facilities.
In short, polyvinylidene fluoride piping has become the ideal piping choice for many high-end and harsh applications due to its excellent chemical resistance, high strength, excellent temperature resistance and good electrical insulation properties.