SELECTING THE KILN BURNER/S TO SUIT YOUR GAS KILN
The following information explains the procedure to select the correct burners and controls for your pottery kiln. Please note the charts are for high pressure propane gas or natural gas burners only, for low pressure (less than 35 kPa) propane or natural gas firing, please consult us.
Determine the total internal volume, not just stacking space, (height x depth x width) in cubic metres or cubic feet. Refer to the appropriate sizing chart. Sizing Chart - Fibre Kilns or Sizing Chart - Brick Kilns. Read the vertical edge of the chart until you reach your kiln size. Read across to intersect the dividing line. Read directly down (at 90o) to obtain the heat input capacity in MJ/hr (megajoules per hour) or BTU/Hour (British Thermal Units). Continue to follow your line until you are within the range of a burner/s size. These are recommended combinations only; it is always better to use more burners as a more even firing will result. ie: 20 cubic foot (total volume) fibre kiln to 1300oC uses approximately 220 MJ/hour, therefore use 2 x 1 1/4" (LK32) burners or 4 x 1" (LK25) burners for more even heat. The charts are sized for average well insulated kilns but are a guide only. There are many factors that will determine the heat input such as the insulation thickness and the design of the kiln. All the calculations are based on a kiln firing to 1300oC. More energy is expended (proportionally) in the last 300oC than at other stages. If firing only to 1080oC or less, you may deduct approximately 30% from the maximum capacity needed. MJ/hour = Megajoules per hour. This is the newer, accepted unit for the heat input. BTU's (British Thermal Units) and MJ are both heat measuring units. 1,000 BTU = 1.055 MJ/Hour.
THE KILN BURNERS
The complete burner, fitted with a fine control needle valve and flame failure is sealed, gas leak tested and has the safety probe securely mounted to the burner tip in the correct position. The optional extras include a pre-heating pilot and gauge. The pilot enables a slow heat rise to dry green ware and is always a handy addition. The pilot is necessary on burners fitted to fibre kilns as the heat will rise far too quickly if you attempt to adjust the main burner only. On multiple burner situations always use the same size burners on the kiln. Fitting a gauge to the burner enables the potter to accurately fire the burner using the fine control needle valve. In multiple burner installations using gauges helps to balance the burners.
KILN BURNER SPARE PARTS AND
A full range of spare parts are available for the kiln burners. The regulator (which must always be used) and gauge, flexible hoses (for non-permanent situations), fittings for the gas cylinder and some copper fittings for the gas fitter.
Use 1/4" copper pipe and fittings up to the input of 230 MJ/hour and 3/8" or 1/2" copper above that. It is better to use two gas bottles and have a manual change over valve and two pigtails (one for each cylinder) between the cylinders and the regulator. Nothing is more annoying than running out of gas near the end of a firing. For large gas usage installations, the four bottle manifold is needed plus the manual change over valve. This enables you to effectively have two bottles per side. Use the four bottle manifold for inputs greater than approximately 300 MJ/hr. It may be more economical to have a tank installation. Please consult your local L.P.Gas supplier for more details.
Digital and analogue pyrometers are available and several varieties of temperature controllers and automatic programmers. The digital type are great for ceramics as you can easily calculate your heat rise by measuring a small change in temperature over a short period of time. They will also indicate rapidly if the temperature is rising or falling at a fast or slow rate.
The temperature controllers are available in two models to cut off the kiln at a pre-set temperature or enable the kiln to soak at a temperature.
The electronic programmable types have the ability to automatically fire the kiln to temperature in pre-set ramps. All the controllers are suitable for controlling electric or gas kilns. The contactor or relay is controlled on an electric kiln and solenoid valves on a gas kiln.
ELECTRONIC FLAME SAFETY
This feature enables the burners to be started remotely and shut in less than 1 second on flame out.
INDUSTRIAL BURNER SYSTEMS
We are expert in the manufacture and supply of sealed type higher velocity burners to fast fire larger kilns or kilns that have a tightly stacked load. Please ask for more details and the appropriate data sheets.
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