Tag: Gas Fired Powder Coating Oven

Gas Powder Coating Oven

Powder coating of metals is often favored by manufacturers because its finish is tougher than conventional paint. Powder coating is abrasion resistant and will not crack, chip, or peel as conventional paint will. Powder coating is typically done through a two-step process: First, the coating is applied to the part electrostatically with powder coating equipment, and then the newly powdered part is cured in an industrial gas powder coating oven under heat to form a skin.

This process is very efficient since the powder wraps around the back of the part for better coverage and ensures 95% material usage of the powder. The powder coating is a dust-like substance that behaves quasi-fluid. with the help of this material property, the powder coating flows through the hoses and gun of powder coating equipment and reaches the part already ionized with – ion. This helps the particle hang on the part and stay there till the part is grounded again. The parts that are coated with powder are either manually, or automatically with the help of a conveyor are taken into the gas oven, of which inside there is a 200 C temperature to melt the powder coating on the parts

Benefits of powder coating and curing in an oven: Heavy-duty construction and quality components Excellent uniformity and heating rates for consistent, high-quality curing results No powder blow-off – reduces rework Uniform heat distribution provides quality cured finishes and optimum cure cycles Quick heat-up rates so you can cure more loads per day Roof-mounted blowers conserve valuable floor space at your facility Fully adjusted and factory tested prior to shipment to reduce installation and start-up times Available with our exclusive energy-efficient oven upgrade

Small Gas Powder Coating Oven

The dimensions of our small powder coating oven start from 1,2m x 1,2m x 1,2m. This is for lab powder coating applications. The lab type oven is used to cure powder coating for samples and small items in small number

Powder coating companies that are doing custom coating can have some special requests for small items and samples. They don’t want to heat up a big oven for this and require a small lab-type box oven. This small oven can also be used for powder coating at home. Some people try to make their own DIY powder coating oven but this usually takes a long time for construction and can have some serious mistakes in manufacturing that can cause inefficiency and even danger to human life.

The powder coating cost usually increases in such DIY powder coating oven types. If the curing won’t be effective, you will need to use a powder coat remover to get the powder off the powder-coated metal has the entire powder coating process once again. The powder coating prices are not that low to let you repeat the same process again and again.

Gas Powder Coating Oven Characteristics

A gas powder coating oven is a crucial component of the powder coating process, responsible for curing the applied powder coating, transforming it into a durable and hard finish. The curing process involves heating the powder particles to a specific temperature for a specified time, allowing them to melt, flow, and crosslink, forming a continuous film on the substrate. Gas powder coating ovens utilize natural gas or propane as the fuel source for the heating process.

Components of a Gas Powder Coating Oven

A typical gas powder coating oven comprises several key components:

1. Gas Burner System: The gas burner system provides the heat source for the curing process. It includes gas valves, regulators, and burners that efficiently combust natural gas or propane to generate hot air.
2. Heat Exchanger: The heat exchanger transfers heat from the combustion gases to the circulating air, ensuring uniform heat distribution within the oven. It may be a finned tube heat exchanger or a plate-type heat exchanger.
3. Air Circulation System: The air circulation system ensures consistent heat transfer to all parts of the workpiece. It includes fans, ducts, and distribution plenums that circulate hot air throughout the oven chamber.
4. Temperature Control System: The temperature control system regulates the temperature within the curing oven, ensuring the powder particles are heated to the correct temperature range for optimal curing. It may involve thermocouples, controllers, and feedback loops.
5. Workpiece Handling System: The workpiece handling system transports the powder-coated workpieces through the curing oven, maintaining proper positioning and exposure to the heat source. It may involve conveyor belts, rotating turntables, or automated robotic systems.
6. Exhaust System: The exhaust system removes fumes and gases generated during the curing process, maintaining a safe and comfortable working environment. It may include fans, ducts, and filtration systems.

Types of Gas Powder Coating Ovens

The specific type of gas powder coating oven used depends on the production volume, workpiece size and shape, desired coating properties, and available space:

1. Batch Ovens: Batch ovens are suitable for low-volume production and allow for manual loading and unloading of workpieces. They may be heated by gas burners, infrared (IR) emitters, or a combination of both.
2. Continuous Ovens: Continuous ovens are designed for high-volume production and incorporate conveyor systems to transport workpieces through the curing process. They offer efficient and consistent curing results.
3. Specialty Ovens: Specialty ovens are designed for specific applications, such as curing complex shapes or achieving high-gloss finishes. They may incorporate specialized heating elements, air circulation patterns, or atmosphere control systems.

Factors Affecting Gas Powder Curing

Several factors influence the effectiveness of gas powder curing:

1. Powder Type: Different powder formulations require specific curing temperatures and times.
2. Substrate Material: The substrate material’s thermal conductivity can affect the heating and curing process.
3. Workpiece Thickness: Thinner workpieces may cure faster than thicker ones.
4. Oven Temperature: Maintaining consistent temperature throughout the oven is crucial for uniform curing.
5. Air Circulation: Proper air circulation ensures even heat distribution and prevents uneven curing.
6. Curing Time: Insufficient curing time can lead to incomplete crosslinking and poor coating performance.

Conclusion

Gas powder coating ovens play a critical role in achieving durable and high-quality powder coatings. By selecting the appropriate curing oven, optimizing curing parameters, and maintaining proper operating conditions, manufacturers can ensure consistent and effective powder curing, resulting in long-lasting, protective, and aesthetically pleasing finishes.

Additional Considerations for Gas Powder Coating Ovens

1. Fuel Efficiency: Choose an oven that utilizes fuel efficiently to minimize operating costs and environmental impact.
2. Maintenance Requirements: Consider the ease of maintenance and availability of spare parts for the oven.
3. Safety Features: Ensure the oven incorporates adequate safety features, such as emergency stop mechanisms and gas leak detection systems.
4. Integration with Existing Systems: Ensure the oven can integrate seamlessly with existing equipment and processes.
5. Compliance with Regulations: Verify the oven complies with relevant safety and environmental regulations.

Temperature Controller

A temperature controller is an essential component of a gas powder coating oven, ensuring that the powder particles are heated to the correct temperature range for optimal curing. This precision control is crucial for achieving consistent and high-quality powder coating results.

Functions of a Temperature Controller

The primary functions of a temperature controller in a gas powder coating oven include:

1. Temperature Monitoring: Continuously monitors the temperature within the oven chamber using thermocouples or other temperature sensors.
2. Temperature Regulation: Adjusts the operation of the gas burners or other heating elements to maintain the desired temperature setpoint.
3. Alarm System: Triggers alarms if the temperature deviates from the setpoint, preventing potential damage to the powder coating or the workpiece.
4. Data Logging: Records temperature data over time, providing valuable insights into oven performance and curing consistency.

Types of Temperature Controllers

Temperature controllers vary in complexity and features, ranging from simple analog controllers to sophisticated digital controllers with advanced control algorithms. The choice of controller depends on the specific requirements of the powder coating oven and the desired level of control accuracy.

1. Analog Temperature Controllers: These controllers utilize mechanical or electrical components to regulate temperature. They are generally less expensive but offer limited control capabilities.
2. PID Temperature Controllers: These controllers employ Proportional-Integral-Derivative (PID) control algorithms, providing more precise and responsive temperature regulation. They are widely used in industrial applications due to their effectiveness.
3. Programmable Temperature Controllers: These controllers offer advanced features like programming temperature profiles, ramp rates, and dwell times, enabling optimized curing processes. They are particularly suitable for complex applications or production lines with varying requirements.

Selection Criteria for Temperature Controllers

When selecting a temperature controller for a gas powder coating oven, consider the following factors:

1. Temperature Range: Ensure the controller can handle the desired curing temperature range for the powder coating being used.
2. Accuracy Requirements: Choose a controller with the necessary accuracy to achieve consistent curing results.
3. Control Algorithm: Select a controller with an appropriate control algorithm, such as PID, for precise temperature regulation.
4. Communication Protocols: Consider if the controller supports communication protocols for integration with other systems or data logging purposes.
5. Safety Features: Ensure the controller incorporates safety features, such as over-temperature alarms and fail-safe mechanisms.

Safety Considerations for Temperature Controller Operation

1. Regular Calibration: Regularly calibrate the temperature controller to maintain accuracy and prevent deviations from the setpoint.
2. Sensor Maintenance: Ensure the temperature sensors are properly installed, maintained, and calibrated for accurate temperature readings.
3. Alarm Monitoring: Pay attention to temperature alarms and promptly address any deviations to prevent potential hazards.
4. Emergency Procedures: Establish clear emergency procedures in case of temperature-related malfunctions or safety incidents.

Conclusion

A temperature controller plays a critical role in ensuring the quality and consistency of powder coating results. By selecting the appropriate controller, maintaining its operation, and adhering to safety guidelines, manufacturers can achieve optimal curing, extend the lifespan of their powder coating equipment, and maintain a safe working environment.

An Electronic Temperature Controller controls temperature conditions. It is a non-profiling type 1/16 DIN single channel controller that features automatic control. Either a time proportioned heat output or a 4-20 ma control signal is used for precise temperature control

Overtemperature Protection

An Electronic Temperature Controller is provided for temperature protection. The Electronic Temperature Controller will remove power to the heating system when an over-temperature condition is detected. Alarm circuitry may be included as an option.

Overtemperature protection is a crucial safety mechanism in various industrial and commercial applications, including powder coating ovens, electrical systems, and machinery. It prevents overheating and potential damage to equipment, materials, and surrounding environments by automatically triggering corrective actions when temperatures exceed safe limits.

Principles of Overtemperature Protection

Overtemperature protection systems utilize various principles to monitor and regulate temperature, including:

1. Temperature Sensors: These sensors, such as thermocouples or RTDs, detect temperature changes and convert them into electrical signals.
2. Control Systems: These systems receive temperature signals from the sensors, compare them to preset thresholds, and initiate appropriate actions when temperatures exceed safe limits.
3. Actuators: These devices, such as valves, switches, or relays, perform the necessary actions to reduce or prevent overheating, such as shutting down heating elements, activating cooling systems, or triggering alarms.

Components of Overtemperature Protection Systems

A typical overtemperature protection system comprises several key components:

1. Temperature Sensors: Strategically placed temperature sensors monitor the temperature of critical components, such as heating elements, bearings, or electrical conductors.
2. Signal Conditioning Units: These units amplify, filter, or convert the raw temperature signals from the sensors into a format compatible with the control system.
3. Control Logic: The control logic, implemented in a programmable logic controller (PLC) or other control device, receives temperature signals, compares them to setpoints, and activates the appropriate actuators.
4. Actuators: Actuators, such as relays, valves, or contactors, perform the necessary actions to prevent overheating, such as shutting down heating elements, opening cooling valves, or triggering alarms.
5. Alarms and Indicators: Alarms and indicators provide visual or audible warnings when temperatures approach or exceed safe limits, alerting operators to take corrective actions.

Applications of Overtemperature Protection

Overtemperature protection systems are widely used in various applications, including:

1. Powder Coating Ovens: Prevent overheating of powder coating materials and substrates, ensuring consistent curing results and minimizing fire hazards.
2. Electrical Systems: Protect electrical components, such as transformers, motors, and cables, from damage caused by excessive temperatures, preventing electrical failures and fire hazards.
3. Machinery: Safeguard machinery components, such as bearings, gears, and engines, from overheating, preventing premature wear, tear, and breakdowns.
4. Industrial Processes: Protect industrial processes, such as chemical reactions, distillation, and polymerization, from runaway conditions that could lead to explosions or hazardous releases.
5. Commercial Appliances: Prevent overheating in appliances such as ovens, stoves, and dryers, minimizing fire risks and ensuring user safety.

Benefits of Overtemperature Protection

Overtemperature protection systems offer several significant benefits:

1. Equipment Protection: Prevent damage to equipment, extending its lifespan and reducing maintenance costs.
2. Safety Enhancement: Minimize fire hazards and protect workers from potential injuries caused by overheating.
3. Process Control: Maintain stable and safe operating conditions for industrial processes, preventing costly disruptions and ensuring product quality.
4. Environmental Protection: Prevent environmental pollution and hazardous releases caused by overheating or uncontrolled reactions.
5. Insurance Compliance: Meet insurance requirements and safety regulations, reducing liability and risk.

Conclusion

Overtemperature protection is an essential safety measure that safeguards equipment, personnel, and the environment from the adverse consequences of overheating. By implementing effective overtemperature protection systems, industries and businesses can prevent costly damages, ensure safe operations, and maintain their reputation for reliability and safety.

Process Timer

A process timer is an essential component of a gas powder coating oven, ensuring that the powder particles are heated for the correct duration to achieve optimal curing. This precise control of curing time is crucial for consistent and high-quality powder coating results.

Functions of a Process Timer

The primary functions of a process timer in a gas powder coating oven include:

1. Time Monitoring: Continuously tracks the elapsed time since the curing process began.
2. Time Regulation: Controls the operation of the gas burners or other heating elements to maintain the desired curing time.
3. Alarm System: Triggers alarms if the curing time exceeds or falls below the setpoint, preventing incomplete or over-curing of the powder coating.
4. Data Logging: Records curing time data over time, providing valuable insights into process consistency and reproducibility.

Types of Process Timers

Process timers vary in complexity and features, ranging from simple mechanical timers to sophisticated digital timers with advanced control algorithms. The choice of timer depends on the specific requirements of the powder coating oven and the desired level of control accuracy.

1. Mechanical Process Timers: These timers utilize mechanical components, such as gears and springs, to track and regulate curing time. They are generally less expensive but offer limited control capabilities.
2. Electronic Process Timers: These timers employ electronic circuits and microcontrollers to provide precise time measurement and control. They are widely used in industrial applications due to their reliability and accuracy.
3. Programmable Process Timers: These timers offer advanced features like programming curing time profiles, ramp rates, and dwell times, enabling optimized curing processes. They are particularly suitable for complex applications or production lines with varying requirements.

Selection Criteria for Process Timers

When selecting a process timer for a gas powder coating oven, consider the following factors:

1. Time Range: Ensure the timer can handle the desired curing time range for the powder coating being used.
2. Accuracy Requirements: Choose a timer with the necessary accuracy to achieve consistent curing results.
3. Control Algorithm: Select a timer with an appropriate control algorithm, such as a proportional-integral-derivative (PID) algorithm, for precise time regulation.
4. Communication Protocols: Consider if the timer supports communication protocols for integration with other systems or data logging purposes.
5. Safety Features: Ensure the timer incorporates safety features, such as over-time alarms and fail-safe mechanisms.

Safety Considerations for Process Timer Operation

1. Regular Calibration: Regularly calibrate the process timer to maintain accuracy and prevent deviations from the setpoint.
2. Alarm Monitoring: Pay attention to time alarms and promptly address any deviations to prevent potential defects or inconsistent curing.
3. Emergency Procedures: Establish clear emergency procedures in case of time-related malfunctions or safety incidents.

Conclusion

A process timer plays a critical role in ensuring the quality and consistency of powder coating results. By selecting the appropriate timer, maintaining its operation, and adhering to safety guidelines, manufacturers can achieve optimal curing, extend the lifespan of their powder coating equipment, and maintain a safe and efficient production process.

A Process Timer is provided, which has five user-selectable timing ranges from 0.01 seconds to 9999 hours. The timer will automatically start timing once the process setpoint temperature is reached. When the total preset time has elapsed, power to the heat control circuitry will be disabled.

Additional Features

EMS Powder Coating Equipment ovens are designed with the capability to incorporate many other optional features for safety purposes, enhanced process control, and a simplified operator interface. Consult a Gruenberg Applications Engineer or our Service Department for more information or questions.

Operating Parameters and Requirements

This equipment is designed to operate safely when the following environmental conditions are met:

• Indoor use only.
• Within a temperature range of 5°C to 30°C (max).
• Maximum relative humidity 90%.

The listed chamber specifications are based on operation at 24° C ambient temperature, the altitude at sea level, and a 60 Hz power supply. Chamber operation utilizing a 50 Hz power supply may derate the listed performance specifications. Equipment damage, personal injury, or death may result if this equipment is operated or maintained by untrained personnel.

Operators and service personnel must be familiar with the location and function of all controls and the inherent dangers of the equipment before operating or maintaining it. TPS shall not be liable for any damages, including incidental and/or consequential damages, regardless of the legal theory asserted, including negligence and/or strict liability.

Observe all safety warnings and operating parameters listed in this manual, as well as all Caution, Danger, and Warning signs or labels mounted on the equipment to reduce the risk of equipment damage and personal injury.

Location and Installation of the Gas Powder Coating Oven

Oven Classification – Electric Heated Units: NFPA 86 Class B ovens are heat utilization equipment operating at approximately atmospheric pressure wherein there are no flammable volatiles or combustible material being heated in the oven.

Oven Classification – Gas Heated Units: NFPA 86 Class A: “Class A ovens and furnaces are heat utilization equipment operating at approximately atmospheric pressure wherein there is a potential explosion or fire hazard that could be occasioned by the presence of flammable volatiles or combustible materials processed or heated in the furnace.”

Do not locate units in areas of wide ambient temperature variation such as near vents or outdoor entrances.

Do not place the unit near combustible materials or hazardous fumes or vapors.

Do not install the unit in a corrosive environment. A corrosive environment may lead to poor performance and deterioration of the unit.

Ventilation: The oven should be installed in an area where there is good air ventilation. Allow a minimum of 5 inches between any wall and any oven side.

Do not position the oven in a manner that would make it difficult to operate your main power disconnect switch.

Make sure the oven is leveled when set up. The floor of the chamber should be leveled with a Spirit Level to +/- 1/8” (3.175 mm) front to back and side to side.

Sometimes control panels are removed to facilitate shipment. When required, replace the panel securely and reconnect numbered electrical wires to matching numbered terminal blocks.

Very Important! Upon completion of the initial installation of the chamber and upon completion of any maintenance procedure, make sure that all access panels that have been removed are reinstalled securely before operating the unit.

Exhaust Connection for Gas Powder Coating Oven

The exhaust connection for a gas powder coating oven is a crucial component of the system, ensuring the safe and efficient removal of fumes, gases, and combustion byproducts generated during the curing process. Proper ventilation is essential for maintaining a healthy and comfortable working environment, preventing fire hazards, and complying with environmental regulations.

Design Considerations for Exhaust Connections

The design of the exhaust connection should take into account several factors:

1. Fume and Gas Generation Rate: The size and capacity of the exhaust system should be proportional to the rate at which fumes and gases are generated during the powder coating process. This ensures effective removal of airborne contaminants.
2. Oven Configuration: The exhaust connection should be positioned strategically to capture fumes and gases effectively from all parts of the oven chamber. This may involve multiple exhaust ports or strategically placed ducts.
3. Fan Capacity: The exhaust fan should be sized appropriately to provide sufficient airflow for the removal of fumes and gases. This ensures proper ventilation and prevents recirculation of contaminants.
4. Ducting System: The ductwork should be designed to minimize pressure drops and ensure smooth airflow from the oven to the exhaust outlet. This optimizes the efficiency of the exhaust system.
5. Filtration System: A filtration system may be necessary to remove particulate matter and other contaminants from the exhaust stream before it is discharged into the atmosphere. This depends on the specific requirements of the powder coating application and environmental regulations.

Safety Considerations for Exhaust Connections

1. Regular Maintenance: Regularly inspect and clean the exhaust system, including ducts, fans, and filters, to maintain optimal performance and prevent fire hazards.
2. Electrical Safety: Ensure proper grounding and electrical safety procedures for the exhaust system components.
3. Emergency Stops: Install and maintain emergency stop mechanisms to halt operations in case of unexpected hazards.
4. Gas Detection Systems: Consider installing gas detection systems to monitor for potentially hazardous concentrations of fumes or gases.
5. Personal Protective Equipment (PPE): Provide PPE, such as respirators, gloves, and safety glasses, when necessary for handling powder coating materials or working near the exhaust system.
6. Training and Documentation: Provide thorough training to operators on proper exhaust system operation and safety procedures. Maintain comprehensive safety documentation.

Conclusion

The exhaust connection plays a vital role in maintaining a safe and environmentally compliant powder coating operation. By designing and maintaining an effective exhaust system, manufacturers can protect their employees, minimize environmental impact, and safeguard their facilities from potential fire hazards.

An exhaust port connection consisting of a 6” O.D. collar is installed with the exhaust blower assembly at the top of the oven. The exhaust housing includes a manual damper. A vent duct should be connected to the exhaust port collar and run to a location outside of the building (as necessary). This should be done in accordance with all local code regulations. Make sure the connection is secure.

Gas Supply Connection for Gas Powder Coating Oven

The gas supply connection for a gas powder coating oven is a critical component that ensures a safe and regulated flow of natural gas or propane to the oven’s burners. Proper gas supply connection is essential for achieving consistent curing results, maintaining equipment efficiency, and preventing potential hazards.

Design Considerations for Gas Supply Connections

The design of the gas supply connection should adhere to several guidelines:

1. Gas Pressure Requirements: The gas supply line must be designed to withstand the pressure requirements of the oven’s burners. Excessive pressure can lead to safety hazards, while insufficient pressure can compromise curing performance.
2. Gas Flow Rate: The gas supply system should be sized to provide the required flow rate for the oven’s burners. This ensures adequate heat generation for proper curing.
3. Pipe Materials: The gas supply piping should be made from appropriate materials that can withstand the pressure, temperature, and potential corrosion associated with natural gas or propane.
4. Valves and Regulators: Install pressure regulators and shut-off valves at appropriate points in the gas supply line to control gas flow and isolate the oven in case of emergencies.
5. Leak Detection: Implement leak detection systems, such as pressure gauges, gas detectors, or soap bubble testing, to identify and promptly address gas leaks.
6. Regular Maintenance: Maintain the gas supply system regularly to ensure its integrity, prevent leaks, and optimize performance.

Safety Considerations for Gas Supply Connections

1. Compliance with Gas Codes: Ensure the gas supply system complies with local, national, and international gas codes and regulations.
2. Qualified Personnel: Only trained and qualified personnel should handle the installation, maintenance, and repair of the gas supply system.
3. Training and Documentation: Provide thorough training to operators on proper gas supply system operation, safety procedures, and emergency response protocols. Maintain comprehensive documentation of gas system installation, maintenance, and inspections.
4. Ventilation: Ensure adequate ventilation in the vicinity of the gas supply system to prevent the accumulation of flammable gases.
5. Emergency Procedures: Establish clear emergency procedures in case of gas leaks, fires, or other gas-related hazards.
6. Personal Protective Equipment (PPE): Provide PPE, such as gloves, safety glasses, and gas detectors, when necessary for working near the gas supply system.

Conclusion

The gas supply connection plays a crucial role in the safe and efficient operation of a gas powder coating oven. By adhering to proper design principles, implementing robust safety measures, and maintaining regular maintenance, manufacturers can ensure the reliability and safety of their powder coating operations.

Gas-fired ovens may use either natural gas or liquid propane for combustion to heat the oven. You must follow your specific supply specifications listed on your General Arrangement Drawing D001 and when listed here.

Important! Please read the entire Gas Heating System section and all vendor manuals / cut sheets to familiarize yourself with all gas components before making your gas supply connection. The gas supply connection is made to a ball valve with a ½” FPT type connection. Make sure the connection is secure and is checked for leaks before operation.
Gas Supply – Liquid Propane: Pressure = xxx PSIG, xxxx CFH
Gas Supply – Natural Gas: Pressure = xxx PSIG, xxxx CFH

Air Circulation of Gas Powder Coating Oven

Gas-fired heating systems are normally installed in walk-in modular ovens. A high-volume airflow system is employed to provide maximum temperature uniformity. The type of air circulation system used depends on the configuration of the unit. Single module units can only employ a horizontal front-to-back airflow type pattern using centrifugal type blower wheels to generate air circulation. Double module units can employ two different types of air circulation systems, as listed below.
• Horizontal front-to-back pattern using centrifugal type blower wheels.
• Compound horizontal pattern using propeller-type fans.

The heating and generation of airflow occur in the conditioning plenum, which is normally located on the right side wall of the oven. Blower wheels or fans are driven with extended shafts by motors mounted in the
control cabinet. Heating is achieved by a gas burner that directs a flame down into a vertical perforated flame tube mounted in the manifold next to the conditioning plenum. Thermocouples used for temperature sensing
are normally mounted in the workspace on the plenum panel.

Airflow Description

Gas ovens using centrifugal type blower wheels for airflow generation employ a horizontal front-to-back type airflow system. The burner manifold is designed with a vertically mounted flame tube along with perforations on the back side of the manifold. Processed air is drawn into the burner manifold and conditioning plenum, and is heated as it mixes with hot air emitted from the flame tube.

Fresh ambient air is also drawn into the plenum where it mixes with the heated air. Conditioned air is discharged into the workspace through perforations near the front of the plenum housing. The air flows back through the workspace in a horizontal manner to condition the product and then returns to the plenum for reconditioning.

A portion of the processed air is exhausted through a port in the chamber ceiling by the exhaust blower. An air intake port with a manual slide damper is installed in the ceiling of each module to allow fresh ambient air to replenish the exhausted air. Slide dampers are mechanically locked to a predetermined minimum opening.

Heating System of Gas Powder Coating Oven

Important Note: Due to the diverse array of configurations available in a gas heating system, this section will describe basic system requirements, standard equipment used, and fundamental operation.

EMS Powder Coating gas heated ovens are designed to operate with either a natural gas supply or a liquid propane supply according to NFPA 86 (National Fire Protection Association) safety standards. To meet NFPA main gas train requirements, a Closed Position Indicator CPI is used for electrical indication of the safety valve’s closed position. A direct-fired type gas system is used in which the flame is shot through a burner manifold in the conditioning plenum.

Recirculating oven air is heated as it is drawn through the flame. Direct-fired systems are typically greater than 90% efficient. Since products of combustion enter the workspace with this type, it is reserved for those processes that are not emission sensitive. However, many safety precautions are employed with a direct-fired system to compensate for the presence of an open flame. The following sections detail the standard gas heating components used and their operation. The actual components used will vary with your application, so it’s important to check your oven specifications.

Exhaust Blower of the Gas Powder Coating Oven

An exhaust blower is standard with all direct-fired systems to serve two purposes. Initially, the blower is used along with a purge air timer to purge oven air for a fixed time before the gas burner is fired. When the purge
cycle time is complete, the exhaust blower is used to maintain a constant exchange of oven air with fresh ambient air. Ambient air is drawn into the oven through slide dampers mounted atop each module.

A differential pressure switch is used to monitor airflow generation by the exhaust blower, and subsequently for correct operation of the blower motor. These devices use a diaphragm to sense pressure and to mechanically trigger a SPDT Snap Switch when the proper pressure is developed across the blower wheel (or fan). Correct rotation of the motor is necessary for the switch to operate properly. If a loss of pressure / airflow were detected, the switch would open and remove power from the gas burner.

Loss of airflow may result from a motor malfunction, a loose blower wheel (or fan), or constricted air intake or exhaust ports. Blower Spark-Proof Design: The blower housing is designed with a non-sparking type construction. The housing and inlet rings are made of aluminum while the blower wheel is made of stainless steel. Should the blower wheel come off its shaft and strike the blower housing or inlet ring, no sparks can be generated between the two metals.

Gas Burner – Combustion Blower

The three elements necessary for combustion are fuel, oxygen, and ignition. The combustion blower supplies a constant flow of fresh air to the burner. The air is mixed with gas by various methods in order to establish ignition and to sustain complete combustion. The combustion motor starts immediately when the OVEN ON switch is closed. A combustion airflow switch monitors airflow from the combustion blower. This is a differential air pressure type, which will shut down the burner if a loss of airflow is detected.

A burner is defined as a device used for the introduction of fuel and air into an oven at the required velocities, turbulence, and concentration to maintain ignition and combustion of fuel. A Blast type burner is normally
used. This burner delivers a combustible mixture under pressure, normally above 0.3 inch W.C. to the combustion zone. Various flame safety devices are installed within the burner.

EMS Powder Coating Equipment

Powder coating equipment is used to apply a thin layer of powder over a metal surface. This type of coating is applied by an electrostatic process and is a very popular method for finishing metal parts.

This type of equipment can be divided into two main categories: automatic and manual. Automatic booths are more popular because they provide better production rates, but they are also more expensive.

A powder booth is an enclosure in which the powder-coating process takes place. Powder-coating equipment includes an oven where the parts are heated to activate the powder, a gun that sprays or brushes on the powder, a conveyor belt that moves parts through the oven, and cartridge-type guns for applying thicker coatings with less overspray.

Powder coating is a technique that is used to provide a finish to metal parts. This technique has been in use for many years and it is still one of the most popular techniques today.

Powder coating equipment consists of booths, ovens, guns, machines, lines and conveyors. A booth can be either automatic or manual. An automatic booth is more expensive than a manual booth but it is also faster and more efficient.