WITH INDIRECT AND DIRECT HEATING
Borum thermoplastic preheaters are melting, heating and mixing the thermoplastic material making it ready for application via the road marking machine. This ensures that you have heated material ready to go at all times.
Furthermore, by preheating the material beforehand in a preheater, any particles that can affect the marking negatively get filtered and do not end up in the machine.
Borum preheaters are designed in two different systems:
- Direct heating (D): The thermoplastic material is heated directly from the burner.
Standard capacities: 300 L, 500 L, 750 L, 1000 L (660 Lb wt, 1100 Lb wt, 1650 Lb wt, 2200 Lb wt)
- Indirect heating (ID): The thermoplastic material is heated via thermal transfer oil in a separate chamber heated by the burner.
Standard capacities: 250 L, 400 L, 600 L, 800 L, 1100 L, 1600 L, 2500 L (550 Lb wt, 880 Lb wt, 1320 Lb wt, 1760 Lb wt, 2420 Lb wt, 3520 Lb wt, 5500 Lb wt)
The size of the preheaters is selected in accordance with the type and size of line work to be performed. As a starting point, it is recommended to get preheaters with 4 times the capacity of the machine.
For trouble-free heating of block, granulate or liquid thermoplastic material.
Efficient vertical double mixer arms, which ensure uniform heating of the material. 50 mm heat insulation. Hydraulic forward/reverse transmission. Preheaters driven by a hydraulic power unit, which can be installed independent of location of preheater. Standard length for connection of hoses and cables 6.0 m.
Diesel oil burner or propane gas system can be supplied for heating. All sizes of preheaters up to 1600 can be delivered as double (twin) units
driven by a common BM PS-15 power unit.
The thermoplastic material is heated via thermal transfer oil in a separate chamber heated by the burner. The oil chamber is found in the preheater's side walls. Therefore, the heating of the thermoplastic material is done from various angles due to the oil chambers surrounding the preheater. This is different compared to the direct heating system where the heating is done from one location - the bottom of the preheater.
Hydraulic motor with agitator bearing.
Start/stop/reverse valve for agitator drive. Vertical agitator with double arms and paddles.
Material container surrounded by heat transfer oil, to distribute heat.
Oil-heated center pipe in material tank. Oil-heated material outlet.
The preheater is equipped with a thermostat for thermoplastic material and for heat transfer oil temperatures from +50 to +270°C. Includes an
integrated display showing actual temperatures.
Better thermal control secures a gentle handling of the thermoplastic material. This ensures optimal application conditions in the temperature working area – maximum heating without risk of material damage
Safe heating conditions via the uniform heat distribution from the thermal oil
Uniform storage temperature in all parts of the preheater – no hot spots
Longer lifetime of the preheater due to the more gentle heat supply from the burner – no overheating of the steel parts
The thermoplastic material is heated directly from the burner, which is placed at the bottom of the preheater. Therefore, the heating of the thermoplastic material is done from this one location - the bottom of the preheater. This is different compared to the indirect system where the heating of the thermoplastic material is done from various angles due to the thermal transfer oil found in the oil chambers surrounding the preheater.
Hydraulic motor with agitator bearing. Start/stop/reverse valve for agitator drive. Agitator with double arms and paddles.
The preheater is equipped with a thermostat for thermoplastic material temperatures from +50 to +250° C.
Includes an integrated display
showing actual thermoplastic temperature.
Quick heating time due to the burner only needing to heat the steel of the preheater – no thermal oil as an in-between medium
Higher melting capacity due to more effect heating in the preheater, which then heats and melts the thermoplastic
Simple construction – no thermal oil reservoir is build into the construction
Lower cost price due to the more simple construction
Both the direct and indirect preheaters are equipped with the high speed agitator and mixing arms, which ensures a perfect mixing of the thermoplastic. The agitator is capable to turn both clock wise (CW) and counter clock wise (CCW).
As an option it is possible to mount an automatic reversing agitator on the preheater with variable speed. With this option it is possible to rotate the agitator slowly when the solid bags with thermoplastic are filled into the preheater and gradually increase the speed as they melt.
The automatic reversing agitator can be set to run CW e.g. 60 seconds, then 5 second pause, then again 15 seconds CCW; this will be repeated continuously when agitator is set on automatic. Such automatic cycle sequences are a major benefit to uniform the thermoplastic when being melted.
To ensure a continuously road marking process it is important to choose the proper size of the preheater. This is done by calculating the material consumption of the road marking machine from the following factors:
- Speed of the machine in km/h
- Marking amount per day
- Mass of the road marking material calculated from marking width, pattern, thickness and density of thermoplastic ρ ~2 kg/litre
A rule of thumb indicates the total preheater volume must be minimum two times the tank capacity of the marking machine.
In continuous operation, with operating equipment, keep the preheater temperature 5 - 15 degrees lower than the application temperature. This is done so that the machine's oil burner can be kept running, thus keeping a little higher oil temperature (relative to the thermoplastic temperature).
At longer breaks in the application work, it is recommended to decrease the temperature of all thermoplastic thermostats, or you can completely turn off the oil burner and keep an eye on the temperature.
How much you decrease the temperature, depends on how long the break is, but the thermoplastic should preferably be below 130-150 degrees before it can be completely shut down for the equipment (stirring, etc.) with regard to settling of the thermoplastic in the preheaters.