Continuous Band Sealer Maintenance Information Reference

The continuous belt continuous band sealer is a heat sealing equipment suitable for small businesses and families. Usually 220V AC power is used, and the heating power is hundreds of watts. The circuit of the sealing machine produced by various manufacturers is similar. Now take the automatic continuous band sealer as an example to analyze the working principle and maintenance examples of its circuit

1. Continuous Band Sealer Circuit principle

The circuit is shown in the attached drawing. The continuous band sealer has a nominal heating power of 350W and a sealing length of 200mm. It has an operating handle, which has two functions: one is to press the plastic bag to be sealed on the heating strip after the operating handle is pressed down, and the other is to press the power switch K to close it. When the switch K is closed, the AC power is stepped down by R1 and R2, and the diode D1 is rectified. The capacitor C1 filters and provides working power to the continuous band sealer machine. The power supply charges C2 through R4 and VR. At the beginning of charging, the voltage on C2 is very small, the transistor Q is in the cut-off state, and its collector is at high level. The triac SCR is triggered by the resistor R6 and the light-emitting tube LED, and the transformer T is powered. The second is to supply power to the heating element RL, and the plastic bag pressed on the RL is heated and sealed. When C2 is charged to cause the transistor Q to be turned on and the collector voltage drops and is not enough to trigger the thyristor, the RL stops heating, lifts the handle, takes out the plastic bag, and the sealing is completed. The handle is lifted, and after switch K is disconnected, C2 is quickly discharged through D2 and R3 to prepare for a charge. The luminous tube LED is used to indicate when the RL is energized. Adjusting the potentiometer VR can change the length of each additional sealing time. The specific adjustment range can be determined according to the power supply voltage at work and the thickness of the sealed plastic.

2. Continuous Band Sealer maintenance examples

Example 1: Depress the handle, switch K closed, RL is energized and heated continuously, and the sealing part of the plastic bag is heated and melted; when repairing, the thyristor is welded and measured with a multimeter, and it is found that the electrode between T1 and T2 has broken down. It can be repaired after replacing the thyristor. The thyristor chooses 3A/600V, such as TLC336A.

Example 2: After pressing down the handle, BL cannot be heat-sealed. Open the casing and visually find that the transformer has been burnt out, and the primary coil of the measuring transformer has been broken. At this time, it can be repaired by replacing it with a transformer with a secondary voltage of about 25V and the same power as the original. The transformer of this machine works intermittently, so its power capacity is about 350W. If the temperature is too high, or the continuous use time is too long, it may cause damage to the transformer, which should be paid attention to during continuous band sealer use.

Example 3: After pressing down the handle, the heating temperature cannot be adjusted when the electric heating is applied. When repairing, mainly check the potentiometer VR. Because VR is often rotated, the carbon diaphragm of VR is damaged. Replace it with the new VR.