**Complete Explanation of Technical Specifications for Anti corrosion Roots Blowers**
1、 Core anti-corrosion grade standard
|Anti corrosion grade | Applicable standards | Protection life | Typical application scenarios|
|----------|---------------|----------|-----------------------|
|C4 level | ISO 12944-5 | 15-20 years | Chemical workshops, coastal areas|
|C5-M grade | ISO 12944-9 | Over 25 years | Offshore platforms, strong acid environments|
|Special anti-corrosion | NACE MR0175 | Customization | High concentration HS/Cl environment|
2、 Anti corrosion scheme for key components
```mermaid
graph LR
A [anti-corrosion fan] -->B [metal parts]
A -->C [Non metallic components]
B -->B1 [Substrate selection]
B -->B2 [Surface Treatment]
B1-->Titanium alloy/2205 duplex steel
B2-->Hot spray aluminum+sealing paint
C -->C1 [Composite Material]
C1-->Fiberglass impeller/PTFE liner
```
3、 Material selection technical parameters
1. * * Metal components**
-Shell: 316L stainless steel (Cl ≤ 1000ppm) or Hastelloy C276 (strong acid)
-Shaft: 1.4529 stainless steel (resistance to pitting corrosion equivalent PREN ≥ 40)
-Fastener: UNS S31803 duplex steel (hardness C32-36)
2. Non metallic components**
-Sealing: Perfluoroether rubber (FFKM) with temperature resistance of -20~300 ℃
-Coating:
-Inner wall: Polyurea spray coating (thickness 2mm, pH resistance 1-14)
-Outer wall: Modified epoxy resin (resistant to UV2000h)
4、 Special anti-corrosion structure design
1. Anti liquid accumulation structure**
-15 ° inclined design at the bottom of the shell
-Set DN20 exhaust port (with PTFE ball valve)
2. Anti galvanic corrosion**
-Insulation gasket (PTFE) added between dissimilar metals
-Cathodic protection: sacrificial anode (Mg Al Zn alloy)
3. Wear resistant and anti-corrosion composite**
-Spray coating WC-10Co4Cr (HV1100) on the leading edge of the impeller
-Shell channel lined with 3mm alumina ceramic
5、 Anti corrosion performance verification
|Test items | Method standards | Qualified indicators|
|------------------|-------------------|------------------------|
|Salt spray test | ASTM B117 | 3000h without substrate corrosion|
|Chemical resistant reagent | ISO 2812-1 | Weight gain ≤ 1mg/cm2 after soaking for 30 days|
|Adhesion | ISO 4624 | ≥ 8MPa (pull-out method)|
6、 Typical industry configuration plan
1. * * Titanium dioxide production line**
-Material: TA2 titanium shell+Monel400 impeller
-Sealing: Double end mechanical seal (buffer solution is ethylene glycol)
-Surface treatment: Micro arc oxidation (film thickness 50 μ m)
2. * * Seawater desalination project**
-Substrate: 254SMO stainless steel
-Coating: HVOF sprayed NiCrMo-625
-Cathodic protection:- 0.85V vs Ag/AgCl
7、 Maintain special requirements
1. Cleaning standards**
-Disable hydrochloric acid cleaning (recommended 5 citric acid cycles)
-High pressure water gun pressure ≤ 50MPa (anti coating peeling)
2. * * Testing cycle**
-Every 3 months: Coating thickness measurement (allowable loss of 10)
-Every year: PT testing (with a focus on inspecting welds)
3. Spare parts management**
-Inventory spare parts need to be vacuum packed (RH ≤ 30)
-Rubber parts have a shelf life of no more than 2 years
8、 Selection calculation case
**Operating condition parameters * *:
-Medium: Mixed gas containing 15HCl
-Temperature: 80 ℃
-Pressure: 98kPa
**Material selection process * *:
1. Check ISO corrosion data:
```math
CR_ {316L}=1.2mm/year>allowable value 0.1mm/year
```
2. Use Hastelloy C276 instead:
```math
CR_{C276} = 0.03mm/year
```
3. Cost comparison:
-316L solution: Initial cost of 150000 yuan, replacement within 3 years
-C276 plan: Initial cost of 450000 yuan, lifespan of 15 years
**Choosing the C276 solution is more economical**
9、 Innovative anti-corrosion technology
1. * * Nanocomposite coating**
-Graphene modified epoxy coating (temperature resistance of 150 ℃)
-Self healing microcapsule technology (self healing within 24 hours after injury)
2. * * Intelligent monitoring system**
-Implantable corrosion sensor (accuracy ± 0.01mm)
-Big data prediction of remaining lifespan (accuracy ≥ 90)
10、 Emergency handling of faults
|Problem phenomenon | Temporary measures | Fundamental solutions|
|------------------|----------------------------------|-------------------------------|
|Local coating peeling | Apply Belzona 1111 for quick repair | Return to factory for re spraying (requires 72 hours for curing)|
|Seal leakage | Inject FEP sealant (temperature resistant to 200 ℃) | Replace FFKM seal|
|Abnormal noise and vibration | Load reduction operation (≤ 80 rated) | Check impeller corrosion balance|
**Note: In strong acid environments with pH<1, it is recommended to use a fully PTFE lined fan (allowing continuous use at temperatures of -50~150 ℃). For working conditions with solid particles, it is necessary to add wear-resistant treatment (such as lining with silicon carbide) on the basis of anti-corrosion design.
