Kiln burner test

An open-air test for the main multiflame T-burner providing most of the heating power and a smaller single-flame burner that provides direct control of vertical heat distribution within the kiln

Small Burner

Specification

• Construction: Two 4” × ½” BSP iron pipes with single flame port (½” to ¾” adaptor)
• Air intake: Drilled barrel connector plus four 7.5 mm venturi holes in mixer tube, adjustable with sliding collar
• Jet: 0.63 mm
• Supply: Propane via adjustable regulator, 50–150 mbar (0.72–2.18 psi)
• Control: Needle valve for fine adjustment
• Theoretical Heat Output: 1.5–3.5 kW (5,000–12,000 BTU/hr)

Video: Small burner test showing flame adjustment at various pressures

Test Result

• Flame Stability: Adjusted from 50–150 mbar (0.72–2.18 psi) with no lift-off or flash-back
• Flame length: From 3 cm to 30 cm.
• Flame Characteristics:
  • With air collar open: Clear blue flame with yellow tips.
  • Air collar closed: Soft yellow flame.
• Observations:
  • The barrel connector alone does not produce a fully aerated flame.
  • The minimum stable size of a clear blue aerated flame is difficult to determine in open air,

Main Burner

Main Multiflame Burner Specification

• Construction: ¾” BSP iron pipe with 1” BSP horizontal arms, nine flame ports
• Venturi: Drilled ¾” barrel adaptor, unrestricted
• Jet: 1.0 mm
• Supply: Propane regulator, 0.5–2 bar (7–30 psi)
• Control: Needle valve for fine adjustment
• Theoretical Heat Output: 14–28 kW (48,000–95,000 BTU/hr)

Video: Main burner test showing flame adjustment at various pressures

Test Results

• Flame Stability: Adjusted from 0.5–2 bar (7–30 psi) with no lift-off or flash-back
• Flame Length: from 2 cm to 30 cm.
• Characteristics: Fully aerated clear flame with pale yellow tips throughout pressure range.
• Observations: Stable and consistent operation across full pressure range with no air adjustment required.

Conclusion

Both burners operated satisfactorily with the simplified L‑shape configuration to fit the redesigned firebox for the test kiln.

• The main multiflame burner delivers stable, high‑power flames over the complete planned pressure range.
• The small burner provides flexible output suitable for bottom heat and candling, but if it is to be used without holes in the mixing tube, the barrel connector would require further drilling to provide complete aeration.