In systems requiring effective sealing—such as drying ovens, thermal chambers, flanges, and industrial equipment—choosing the correct size of rectangular silicone rubber seals is critical for sealing performance, durability, and operational efficiency. Incorrect sizing can lead to leakage and reduced service life.

Why Proper Sizing Matters

  • Undersized seals → insufficient compression, leakage risk
  • Oversized seals → difficult installation, premature deformation

???? Proper selection helps:

  • Ensure optimal sealing performance
  • Extend service life
  • Reduce maintenance costs

Key Parameters to Determine

1. Sealing Gap

  • Measure the distance between two surfaces when closed
  • This is the most critical factor

???? Use a caliper or feeler gauge for accuracy.

2. Compression Ratio

Silicone seals typically perform best when compressed:

  • 20% – 40% of their height

???? Example:

  • Gap = 10 mm → choose seal height ≈ 12–14 mm

3. Contact Width

  • Depends on the sealing surface area
  • Larger surfaces require wider seals

???? Ensures even load distribution and better sealing.

4. Working Environment

Consider:

  • Operating temperature
  • Pressure conditions
  • Exposure to chemicals

???? Helps determine the appropriate silicone grade and dimensions.

Basic Sizing Rule

A commonly used guideline:

  • Seal height = gap + 10% – 30%
  • Seal width = 1.2 – 2 times the height

???? These ratios are widely applied in engineering practice.

Common Rectangular Silicone Seal Sizes

Small Sizes

  • 5 × 10 mm
  • 8 × 12 mm
    ???? For small equipment and narrow gaps

Medium Sizes

  • 10 × 20 mm
  • 12 × 25 mm
  • 15 × 30 mm
    ???? For standard cabinets and industrial systems

Large Sizes

  • 20 × 40 mm
  • 25 × 50 mm
    ???? For ovens and heavy-duty industrial applications

Custom Sizes

  • Manufactured based on technical drawings
  • Adjustable thickness and width
  • Available in cut lengths or endless loops

Common Mistakes to Avoid

  • Selecting without actual measurement
  • Ignoring compression ratio
  • Choosing overly thick seals that hinder closure
  • Overlooking operating temperature conditions

???? These mistakes significantly reduce sealing efficiency.

Practical Engineering Tips

  • Choose a seal slightly larger than the gap for proper compression
  • Avoid overly hard materials for small gaps
  • For high-temperature systems, use heat-resistant silicone
  • Conduct trial installation before mass application

Selecting the correct size of rectangular silicone rubber seals is essential for achieving reliable sealing and long-term durability. Accurate gap measurement, proper compression calculation, and correct dimensioning will ensure stable system performance and cost efficiency