The primary function of a hopper dryer is to store our material. It stores our raw material and pre-dries it to eliminate moisture.
What you see on the screen is the upper tank of the hopper dryer. It is also known as the hopper tank. The glass-like section on it is called the sight glass. Using this glass, we can visually estimate the amount of material inside the hopper.
This here is the screen separator. There are two screen separators inside:
The upper one has a triangular shape
The lower one has a conical shape, which fits perfectly
You can also see this magnet section. The magnet rotates continuously, and due to its rotation, the material is transferred from the hopper to the barrel.
This side hole you see is connected to the blower. When the blower is turned on, air flows through it. Below the blower, heaters are installed. When heating is activated, air moves through the blower and reaches the hopper dryer.
The electrical control box, which we use to control and operate the blower and set the temperature as needed. Recommended temperatures for various plastic materials are provided on it.
Why is it conical?
When the material moves from the tank to the lower cone, it ensures that it does not spread randomly and moves directly toward the centre of gravity.
The upper triangular section prevents bulk material accumulation by regulating the flow smoothly.
This ring hook you see is used to open and close the hopper tank and lower cone. If an emergency occurs and we need to stop the material flow or if there is a fault, we can pull this rod to move the hopper accordingly.
Here is the base sight glass. As mentioned earlier, the magnet is inside it. The magnet prevents metal impurities from entering the barrel. You can see how the magnet works when I bring a metal object close to it.
The hopper dryer is divided into two sections:
The upper section (hopper tank)
The lower section (lower cone)
Both sections are connected by ring hooks.
This is the electrical controller of the hopper dryer. It displays recommended temperature settings:
PE: 80°C for two hours
PS & ABS: 82°C
To turn on the blower, we press this button. See how the blower starts operating.
The electrical box has all the wire connections and functions:
Blower connections : Electrical control settings
Power supply and distribution to different stages
This rod is used to pull and adjust the system. There is an attaching sheet inside.
Here is the air discharge elbow, which releases air after it has been heated.
Manually loaded PP material into the hopper.
Next, look at this—this is called the slip gate. We need to align it to the centre. The circle you see—only when it is aligned in the centre will the material flow from the hopper to the barrel. Otherwise, it remains closed. Now, we have opened it, and the material has moved from the hopper to the barrel.
Now, let’s move on to setting the temperature. Since we are using PP material, we need to set the temperature to 80°C.
You can see that after turning both buttons on, the blower and the setting function are activated. Now, we will gradually increase the temperature to 80°C by pressing the button.
Pressing the lower side of the button will increase the number.
Pressing the upper side will decrease the number.
We increased the temperature step by step—36, 37, 38, 39…—until it reached 80°C. The temperature will gradually rise until it stabilizes at 80°C.
If we need to reset at any point, we can press the reset button, which will instantly bring the setting back to zero.
Automatic Loader
Now, let’s learn about the automatic loader.
The pipe you see here is the suction pump.
We store material in a separate place.
The suction pump pulls the material from the storage and transfers it to the hopper dryer.
The rest of the settings are the same as the manual hopper dryer. The blower and other functions remain unchanged.
Control Settings
The ON switch activates the system.
The timer setting allows loading at regular intervals.
For example, if set to 21 seconds, the machine will load material every 21 seconds.
When the material level is low, an alarm is triggered.
