1. Installation of heating rod
Before installing the electric heating rod, check whether the equipment is defective, and use a 1000V shaker to measure the insulation resistance between the conductive part and the shell, the insulation resistance is 1.5～10MΩ, and the 4mm2 or more stranded copper wire must be used for reliable grounding during installation. Ground resistance ≤10Ω.
When electrical wiring, it must be installed in strict accordance with the requirements of electrical explosion-proof regulations, and the joints of the junction box must be coated with industrial petroleum jelly to ensure that the seal is intact. It is strictly forbidden to use the knife switch to control the operation of the electric heating rod.
1.1 Installation of straight electric heating rod
a The arrangement of the electric heating rod in the oil tank is shown in Figure 3 and Figure 4.
b Installation method: DRB type electric heating rod is installed horizontally. First weld the installation nipple on the oil tank (whether there is a reinforced ring plate on the tank wall is determined by the process design, the installation nipple is provided by us, and the specifications are shown in Table 1), and the electric heating rod is passed through the connecting flange on the installation nipple Installed on the tank, an oil-resistant asbestos rubber gasket should be added between the two flanges, and the bolts should be used to fasten it without leakage (see Figure 5). The inlet of the junction box must be installed downwards. A bracket should be added to the rod body in the tank, and the bracket should be prepared by the user (see Figure 6). The highest position of the rod installation must be controlled below the lowest working level of the oil tank process design.
Single stick two sticks three sticks four sticks six sticks nine to eighteen sticks (Uniform perimeter)
Figure 3: Plane layout of straight electric heating rods on vertical oil tanks
Figure 4: Horizontal installation of straight electric heating rods on horizontal oil tanks (small oil tanks below 60 cubic meters)
Picture 5: DRB type electric heating rod installation short section
Picture 6: Electric heating rod bracket in the tank
1.2 Installation of right-angle electric heating rod
The right-angle electric heating rod can be inserted from the upper manhole of the oil tank, so that the lower part of the electric heating rod is placed horizontally at the bottom of the oil tank (see Figure 7 and Figure 8). The electric heating rod power cable shall be connected to the electric heating rod junction box by the explosion-proof hose laying method in accordance with the explosion-proof requirements. The contact position between the vertical pipe section and the tank outlet shall be covered with a rubber insulating plate with a thickness of more than 6mm and then fixed firmly to the tank body. Avoid sparks caused by swimming collisions. When installing, remember to make a ground connection wire between the rod and the tank shell.
Solemn warning: Because right-angle rods usually cannot be installed with liquid level controllers, users must formulate operating procedures when draining oil, requiring manual power to be disconnected manually, and the liquid level must be checked before re-powering, if the liquid level is low For heating rods, it is strictly prohibited to switch on and send power (try to control the heating part of the horizontal section to be placed below the oil outlet position).
Picture 7: Installation of the right-angle electric heating rod on the horizontal oil tank
Picture 8: Installation of the right-angle electric heating rod on the vertical oil tank
2. Supporting device installation:
2.1 Control cabinet installation and electrical wiring
Non-explosion-proof electric heating control cabinet should be installed outside the explosion-proof area (safe area). The box body should be vertical when installing, and the grounding wire should be firm and reliable. The floor type requires anchor bolts to fix the box on the foundation.
According to the requirements of explosion-proof regulations, copper core cables are required for power cables and control cables, and their cross-sections should be selected according to the power of the heating rod (the actual cable cross-section should be re-checked by the design according to the voltage drop) and provided by the manufacturer The wiring diagram is correctly wired.
2.2 Installation of temperature measuring resistance:
Because the oil in the tank presents a non-uniform temperature field, the relative position of the temperature measuring resistor and the heating rod should be selected to reflect the true temperature of the oil inside the tank. It is recommended to install it according to the position shown in Figure 9.
Installation method: the temperature measuring resistor is installed in the steel sheathing tube, and the steel sheathing tube is welded to the wall of the oil tank. Use a proper amount of transformer oil, and fasten the positioning screws after inserting the temperature measuring resistor into the steel sheath.
Figure 9: The relative position of the temperature measuring resistor and the heating rod installation
Figure 10: Installation of the temperature measuring resistor on the oil tank
2.3 Installation of float level controller:
The relative position of the float level controller and the electric heating rod (see Figure 11), the installation sub-section is welded horizontally on the tank wall, and the float level controller is installed on the sub-section by flange connection. Flange Asbestos rubber pads are needed between. The installation puppet is provided by the product manufacturer, and the outer diameter is Φ90mm (see Figure 12).
Figure 11: The relative position of the float controller and the heating rod
Figure 12: Installation of the float controller on the oil tank
Note: When arranging the relative positions of the electric heating rod, the float level controller, and the temperature measuring resistor, the lowest position of the float should be 150mm higher than the upper surface of the electric heating rod. At the same time, it should be 100mm higher than the bottom end of the platinum thermal resistance.
3. Trial run
Check before trial operation
Check whether the installation positions of the heating rods and supporting components are correct, whether the connecting bolts are loose, the grounding has been done reliably, and whether the grounding resistance is qualified. Check whether the electrical wiring conforms to the drawing, whether the wiring process meets the installation requirements, and whether the bolt connection is firm. Use a 1000V shaker to check whether the live part and the shell are well insulated, and the insulation resistance is ≥1.5MΩ (the insulation resistance of the marine heating rod is ≥10MΩ). Check whether the over-temperature protection sensor is connected. Check whether the oil level in the oil tank is higher than the top of the heating rod. Whether all electrical equipment and wiring requirements comply with explosion-proof regulations (when used in explosion-proof places).
Trial run
Set various process temperature constants according to the temperature regulator manual. Turn the switch to the manual position and then power on. Observe whether the components and circuits in the electric control cabinet work normally and whether there is any abnormality. Measure the voltage and current of each phase of the heating rod, and make a record. After 2 hours of operation in the manual position, the condition is normal, you can turn the switch to the automatic position and put the equipment into automatic operation.
