Temperature inconsistencies are observed as factors contributing to burning problems in the baking oven. These issues can affect product quality, increase rejection rates and cause production delays.
When it comes to direct gas-fired ovens, they must have a constant gas pressure level, good gas control, and sufficient gas flow. Any of these issues can affect the production integrity.
For the industrial biscuit oven, it is preferable to determine the cause of the problem, rather than constantly changing oven temperatures. Common issues on direct gas fired ovens can be detected and rectified by maintenance workers to create uniformity amongst the products and minimise unplanned downtime.
Common Direct Gas Fired Oven Heating Problems and Their Solutions
1. Uneven Heat Distribution
The problem occurs because some of the biscuits get darker on one side of the conveyor, and not evenly, resulting in poor uniformity in colour, texture and moisture. The cause of the problem may be stuck burners, uneven burner function, or incorrect burner zones.
To solve the problem, measurement of temperatures in the baking chamber against the operating parameters is needed. Another important aspect in solving the problem is hiring technicians for burner, vent, and insulation monitoring/detection.
In addition, temperature conditions have to be stable along the entire production chain of hard biscuits and crackers. Otherwise, the temperature, colour, and crispness of whole batches may differ.
2. Slow Oven Preheating
The problem is that the oven is slower to reach the target temperature, which results in production delays and higher energy consumption. The reasons for temperature problems can include low gas pressure, malfunctioning burners, bad door seals, broken heaters, or bad temperature gauges.
The challenge can be solved by checking the preheating time compared to the equipment’s normal time. A team of professionals needs to conduct an inspection of gas pressure, the burner status, and insulation. Replacing broken parts might be needed.
Also, do not change the heating settings for slow preheating. This will cause single zone overheating without actually solving the problem.
3. Frequent Burner Shutdowns
The burners do not ignite and fire as intended, causing the oven to lose heat. Common causes are ignition system malfunction, ignition sensor malfunction, gas pressure change, electrical problem, or limited amount of air to burn the gas.
Resolve the problem by using the fault log and conducting a gas, flame, and safety check. Use only manufacturer-approved procedures to restart the biscuit manufacturing equipment.
Continuous biscuit production lines may lead to unwanted shutdowns of the burner, causing delays in the baking process and also interfering with the activities further down the line. If not maintained properly, burner safety systems can be a cause of unplanned stoppage incidents.
A safety precaution is not to attempt to bypass flame protection devices.
4. Burnt Surfaces and Undercooked Centres
The one thing that’s wrong with biscuits is that they are dark brown on the outside and soft or overcooked on the inside. These can result from too much heat from the top or too little heat from the bottom, or a lack of a correct temperature profile, due to incorrect thickness of dough or conveyor speed.
Check the temperature in all baking zones, not just the temperature. Control the thickness of dough, moisture content of product, and conveyor speed. Carry out experimental procedures and data analysis over a number of trials with controlled changes.
The conditions for baking differ according to the products. For instance, the soft dough cookies, compared to the hard biscuits, can have different behaviours upon exposure to heat because of differences in formulation, thickness, and moisture content. The production settings are then customized based on the recipe.
5. Inaccurate or Fluctuating Temperature Readings
The problem: The temperature shown on the control panel is the set temperature, but the finished biscuit is overbaked or underbaked, or, the temperature is not constant.
This could be caused by faulty sensors, poor wiring connections, improper sensor calibration or improper temperature setup.
Use calibrated measurement instruments suitable for the context and examine readings from instruments. Pay close attention to inspecting the connecting wires and sensors, and organise their calibration and replacement if needed.
6. Excessive Gas Consumption
The issue is that despite similar levels of production and operating temperature, gas consumption is rising. Some of the likely causes are leaky insulation, combustion inefficiency, many opportunities for wasted heat, or improper settings.
Track gas usage in relation to the finished product rather than just by the metre reading. Examining preheating time and idle times is essential.
Small fuel savings will undoubtedly result in significant savings for the companies with multiple ovens working at the same time.
7. Conveyor Speed and Heating Are Not Properly Coordinated
The problem: Biscuits are undercooked or overcooked despite the constant oven temperature.
Some causes of this are the conveyor speed being too fast or too slow, mechanical tracking problems, product spacing problems, and a faulty baking profile not meeting production specifications.
Solution: Confirm conveyor speed against acceptable speeds and check the drive and tracking mechanism. Keep the spacing of the products even and check the interrelationship of conveyor speed, temperature of the zone, and end moisture content.
Preventive Maintenance for Reliable Oven Performance
Fixing defects is very important, but a good maintenance programme is needed to stop the heating problems from occurring again. The industrial biscuit oven works due to the co-ordination of the burners, sensors, insulation, conveyor, and control system.
The food and beverage manufacturing energy-efficient guidance by the Australian Government recognises opportunities where it helps to achieve more energy efficiency by monitoring the processes and improving biscuit manufacturing equipment’s efficiency. In combination with annual maintenance of machines, it will help be cost-effective.
A good maintenance plan has to include:
- Check the temperature reading, alarms, and any working conditions daily
- Make sure that the accuracy of temperature measurement has been checked according to the required frequency of calibration
- Check for visible seals and insulation degradation
- Check warming time, downtime, and the number of rejected goods.
- Re-validate recipes or output when setting changes.
With these records, you can figure out what issue the equipment may have and be responsible for changes in the dough formulation, dough thickness, moisture, etc. It also allows maintenance personnel to detect the issues regularly and avoid the influence on the production process.
Conclusion
In order to overcome any problems related to direct gas firing ovens, it is necessary to use the correct methods connected with burner operation, temperature control, air circulation, and insulation. Regular maintenance visits, appropriate monitoring, and preventive maintenance are essential for the consistency of the baking process and avoidance of production downtime.
New Era supplies the biscuit and cookie production lines, as well as convection and thermal ovens that are suitable for bakers looking for complete baking solutions. The right equipment and its adequate operation will allow you to get the right products.
Explore New Era’s baking ovens and production solutions to find equipment suited to your manufacturing needs.
FAQs
1. What is the reason for non-uniform heating of a direct gas fired oven?
If burns are clogged or zone settings are not correct, if there is an airflow restriction or damage to the insulation, there can be uneven heating. By taking a temperature check and doing a professional burner inspection, you can discover the cause.
2. Why does an industrial biscuit oven consume excessive gas?
High consumption can be a sign of excessive heat loss, poor combustion, or extended idling time. Keep track of fuel consumption per tonne and audit the heating system on a regular basis.
3. How do manufacturers avoid the issue of recurring heating problems in ovens?
Implement regular burners, sensors, insulation, conveyor systems, and safety controls. Record faults and temperature variations and detect recurring problems.
4. Does change in temperature impact biscuit quality?
Yes. The inconsistent fluctuations in temperature can lead to changes in colour, texture, moisture, and crispness. Appropriate conveyor speeds and steady heating profiles maintain a uniform baking.