Infrared dryers with gas (direct): OPTI THERM model

Safety valve

 The safety valve is fitted to the gas supply line and switches off the gas supply to the dryer when there is an emergency stop, for example, or if the conveyor belt is switched off. 

Gas control sections

 The gas control sections control the gas volume to the gas infrared radiators inside the dryer, depending on the heat energy required. The motor valve controls the gas flow. Two pressure monitors also check the gas pressure, which must be a minimum of 3 mbar and a maximum of 25 mbar. If the pressure falls below the minimum of 3 mbar or exceeds the permitted maximum pressure of 25 mbar, the gas supply is shut off by solenoid valves. 

Combustion air fans

The combustion air fans (Oxy-Fans) supply the necessary combustion air for the gas infrared radiators inside the dryer. Pressure monitors check the combustion air supply and switch the system off if the air pressure in the line is insufficient. 

Flameless gas infrared radiators

The gas infrared radiators are installed inside the dryer. The gas infrared radiation systems operate using catalytic oxidation. Catalytic oxidation is a chemical reaction that is activated by means of a catalyst, the properties of which do not change over time. The gas flows into the burner and reacts with the oxygen in the combustion air supply. The contact of the gas with the oxygen via the pre-heated catalyst oxidises the gas. This creates the infrared heat energy. The reaction is exothermic and releases heat in the form of infrared radiation in the wavelength range of 3.5 µm to 5.5 µm. The catalytic combustion creates only CO2 (carbon dioxide) and H2O (water), with no release of carbon monoxide (CO), nitrogen dioxide (NOX) or hydrocarbons (HC). 

Temperature measuring device: 
 OPTI THERM model

With the OPTI THERM temperature measuring device, the temperature of the leather is measured directly in each zone of the dryer and controlled according to a preselected value via the process automation system. This allows the dryer to be set precisely. It guarantees the best dryer values and ensures the best possible interaction of the chemicals released.
 Measuring and regulating the leather temperature in each zone, instead of measuring the air temperature or temperature of the radiators, avoids putting energy into the leather unnecessarily and drastically reduces energy consumption. “Shrinkage” is also reduced if the leather is treated with less heat energy. 

Pyrometers

Pyrometers are installed at the exit to each zone. The pyrometers are infrared temperature sensors that work without contact. They measure the infrared radiation emitted by the leather as it passes through and calculate the surface temperature on that basis. In order to keep the lens on the pyrometer clean, it is flushed with a constant air flow of 0.2 bar. This air flow keeps the lens free of dust particles, precipitation, dew and condensation. 

Waste air volume control: ECO VAC model

When the gas infrared radiators in the dryer are in operation, a certain volume of waste air is required to take away the vaporised water (H2O) that forms during drying. In the waste air duct, a sensor measures the relative humidity of the waste air. Frequency-controlled waste air fans regulate the waste air volume to keep it in the optimal range according to the preselected relative humidity.

Residual moisture measurement: Moisture Matic model

On leaving the drying tunnel and the cooling system, the sensor measures the residual moisture in the leather at various points along a conveyor belt. The current residual moisture measurement and the average residual moisture of the piece of leather can be seen on the display. 

Process automation: YIELD COMMAND

The YIELD COMMAND process automation system is used primarily for optimal guidance of the drying process. This saves a lot of energy and there is less shrinkage. In addition to pure temperature measurement, other features can be implemented for better operation and data archiving. The process data recorded can be stored either locally or on the web (Azure or AWS). 

In future, all GloboCord software versions will be equipped with an interface with our partner VISIDAT. In this way, the customer can see the current process data at any time and optimise and adjust the drying process as necessary. This means better profitability and energy savings of up to 50%. 

Working width/length

Width: 1,800 to 3,400 mm (customised widths on request) 

Length: 2,000 mm per zone (number of zones on request)