IHF Chemical Pump Seal
The IHF chemical pump is a fluoroplastic-lined centrifugal pump designed for transferring highly corrosive and oxidizing media. The matching mechanical seal must meet three core requirements: chemical corrosion resistance, resistance to medium erosion, and compatibility with the fluoroplastic pump structure. Below is comprehensive technical information about this seal:
1. Compatible Types & Core Structure
Based on the hazard level of the conveyed medium, IHF chemical pumps are equipped with two mainstream seal types:
| Seal Type |
Applicable Working Conditions |
Structural Features |
| Single-face unbalanced mechanical seal |
Conventional corrosive media (e.g., dilute sulfuric acid, sodium hydroxide solution), non-toxic, low-volatility media |
1. Simple structure, low cost
2. Torque transmission via multi-spring or single-spring
3. Secondary seal directly fits the fluoroplastic pump shaft sleeve, no risk of shaft sleeve wear
4. No external buffer fluid system required, easy to install and maintain
|
| Double-face balanced mechanical seal |
Highly toxic, volatile, flammable/explosive media (e.g., concentrated nitric acid, organic solvents) |
1. Double-seal-face design, with buffer/isolation fluid filled in the intermediate cavity
2. Balanced structure reduces seal face specific pressure, extending service life
3. Compatible with API-standard flushing schemes, enabling zero leakage
4. Requires a matching buffer fluid circulation system to enhance safety
|
General Structural Advantages
- The seal chamber seamlessly adapts to the fluoroplastic lining of the IHF pump; no pump body modification is needed during installation
- The shaft sleeve uses 316L stainless steel + PTFE coating to resist medium corrosion and shaft wear
- The stationary seat adopts a split design to avoid damaging the pump body’s fluoroplastic lining during installation
2. Key Technical Performance Parameters
| Parameter Category |
Single-face Seal |
Double-face Seal |
| Applicable Pressure Range |
≤1.0 MPa (10 bar) |
≤1.6 MPa (16 bar) |
| Applicable Temperature Range |
-20°C ~ 200°C (depending on secondary seal material) |
-40°C ~ 250°C (when paired with metal bellows structure) |
| Applicable Rotational Speed |
≤3000 rpm |
≤3000 rpm |
| Shaft Diameter Compatibility Range |
20 mm ~ 100 mm (covers all IHF100~IHF200 pump models) |
25 mm ~ 120 mm |
| Allowable Shaft Runout |
≤0.05 mm |
≤0.03 mm |
| Leakage Standard |
≤5 drops/min (in clean water conditions) |
Zero leakage (when buffer fluid circulation is normal) |
3. Core Material Selection Scheme (Classified by Medium Characteristics)
Material selection for IHF pump seals directly determines seal life; it should be tailored to the medium’s corrosiveness, temperature, and solid content:
| Conveyed Medium Type |
Seal Face Material Combination |
Metal Component Material |
Secondary Seal Material |
Expected Service Life |
| Dilute acids/alkalis/salt solutions (e.g., 5% sulfuric acid, NaOH) |
Silicon Carbide (SiC) / Impregnated Graphite |
316L Stainless Steel |
Fluororubber (FKM) |
8000~12000 h |
| Concentrated acids/strong oxidizers (e.g., concentrated nitric acid, hydrogen peroxide) |
Silicon Carbide (SiC) / Silicon Carbide (SiC) |
Hastelloy C276 |
Perfluoroelastomer (FFKM) |
6000~10000 h |
| Organic solvents |
Tungsten Carbide (WC) / Silicon Carbide (SiC) |
316L Stainless Steel |
Polytetrafluoroethylene (PTFE) |
10000~15000 h |
| Media containing solid particles (e.g., acid/alkali solutions with sediment) |
Tungsten Carbide (WC) / Tungsten Carbide (WC) |
316L Stainless Steel + Ceramic Coating |
Fluororubber (FKM) |
3000~5000 h |
4. Key Installation & Maintenance Points
1. Installation Precautions (Adapted to IHF Fluoroplastic Pump Characteristics)
- Do not strike seal components with metal tools to avoid damaging the pump body’s fluoroplastic lining
- Strictly control the seal compression to 3~5 mm; excessive compression causes seal face overheating and wear, while insufficient compression leads to leakage
- Clean the seal chamber and shaft sleeve surface before installation (no impurities or burrs) to avoid scratching the seal face
- The fit tolerance between the shaft sleeve and pump shaft should be H7/h6 to ensure coaxiality and reduce seal eccentric wear
2. Daily Maintenance Points
- Regularly check leakage; shut down for maintenance if leakage exceeds 10 drops/min
- For particle-containing media, equip a flushing pipeline (inject clean water) to prevent particles from entering the seal face
- Replace secondary seals (FKM/PTFE) every 6 months to avoid aging and failure
- When storing the pump for long periods, drain the medium, run the pump with clean water for 5 minutes to clean the seal face, then seal it for storage
5. Common Failures & Solutions
| Failure Phenomenon |
Core Cause |
Targeted Solution |
| Seal face overheating/smoking |
1. Excessive seal compression
2. No flushing fluid, dry friction on seal face
3. Excessive shaft runout
|
1. Adjust compression to the standard range
2. Activate the flushing pipeline and inject clean medium
3. Overhaul the pump shaft and bearings to correct coaxiality
|
| Excessive medium leakage |
1. Aged/deformed secondary seal
2. Scratched/worn seal face
3. Spring failure
|
1. Replace with new secondary seals
2. Lap or replace the seal face
3. Replace with springs of the same specification
|
| Abnormal noise during seal operation |
1. Spring detachment/jamming
2. Loose shaft sleeve
3. Impurities entering the seal chamber
|
1. Disassemble the seal and reinstall the spring
2. Tighten the shaft sleeve lock nut
3. Clean the seal chamber and check for flushing pipeline blockages
|
6. Core Selection Principles
- For highly toxic, volatile media, prioritize double-face balanced seals with a matching buffer fluid system
- For particle-containing media, prioritize hard alloy seal faces + flushing schemes
- For high-temperature media (>180°C), prioritize metal bellows structures instead of rubber secondary seals
