Guidelines for selecting sealant for check valve of Roots blower**
**Three dimensional consideration of temperature resistance, pressure resistance, and chemical compatibility**
**1. Core performance indicators of sealant**
Check valve sealant must meet the following requirements simultaneously:
-Temperature resistance range: When the Roots blower is running, the valve body temperature can reach 80-120 ℃, and the sealant needs to withstand -40 ℃ to 150 ℃;
-* * Compression resistance * *: maintains elastic deformation of no more than 5 under pressure of 0.6~1.0MPa;
-Media compatibility: Resistance to lubricating oil, dust, and possible chemical corrosion.
**2. Comparison of mainstream sealant types**
|Type | Applicable Temperature | Compressive Strength | Chemical Stability | Construction Difficulty|
|------------|------------|----------|------------|----------|
|Silicone rubber | -60~200 ℃ | Medium | Excellent | Easy|
|Fluororubber | -20~250 ℃ | High | Excellent | Difficult|
|Polyurethane | -30~100 ℃ | High | Good | Medium|
|Epoxy resin | -50~180 ℃ | | Excellent | Requires preheating|
**3. Key points of construction technology**
-Surface treatment: To achieve a Sa2.5 sandblasting roughness, acetone should be used for degreasing;
-Coating thickness: Single layer thickness should be controlled within 0.5-1mm, and multiple layers should be cross coated;
-* * Curing control * *: Environmental humidity ≤ 70, fluororubber needs to undergo secondary vulcanization treatment (200 ℃ × 4h).
