I. Applications: The fully automatic mixing machine is an essential piece of equipment for preparing asphalt-sandstone or cement-sandstone mixture samples. This machine fully complies with all the requirements outlined in the Ministry of Transport’s JTG E20-2011 *Standard Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering*. Currently, it has been widely adopted in laboratories across research, construction, and supervision departments within the highway system. II. Structure and Working Principle: Figure 1 illustrates the structural diagram of the machine. It consists of three main components: the heating pot, the mixer, and the lifting mechanism. - **Heating Pot**: The temperature of the heating pot can be set freely between room temperature and 250°C, with automatic temperature control. - **Mixer**: The mixer comprises a stirring head, a motor, and stirring blades. During operation, the stirring blades rotate both around the pot (revolution) and independently (rotation), thoroughly blending the mixture. The mixing time is precisely controlled by a timer, which can be adjusted freely from 1 to 9,999 seconds. - **Lifting Mechanism**: This mechanism includes a motor, a belt-driven reducer, and a lead screw, enabling the mixer to move up and down. When loading or unloading materials, the mixer rises to its highest position; during mixing, it descends to its lowest position. Figure 2 clearly depicts the machine’s three distinct operational states: (1) Loading (2) Mixing (3) Unloading **Figure 2: Three Different Operational States of the Mixing Machine** III. Main Technical Specifications: - Mixing Capacity: 10 liters / 20 liters - Heating Pot Temperature Range: Room Temperature to 250°C (freely adjustable) - Temperature Control Accuracy: ±3°C - Mixing Time: 1 to 9,999 seconds (freely adjustable) - Stirring Blade Speed: - Revolution: 48 RPM - Rotation: 80 RPM - Operating Conditions: - Temperature: -10°C to 40°C - Relative Humidity: Not exceeding 80% - Power Supply Voltage: ~220V ±10%, Current: 20A IV. Usage Instructions: 1. **Machine Installation**: After unpacking the machine, proceed with installation on a stable surface with a solid foundation. Ensure the machine is positioned at least 0.6 meters away from walls and nearby fixed objects. Place the machine on a concrete base, ensuring it remains steady without any vibrations. Use anchor bolts to secure the machine firmly in place. For ease of operation, the machine features a master power switch. Simply plug in the power cord, and the machine will enter its ready-to-use state. To start or stop the machine during operation, press the "Master Power" button on the control panel. **Note**: Always ensure proper grounding during power installation to prevent electric shock or injury due to leakage current. 2. **Control Panel Explanation**: The human-machine interface is illustrated in Figure 3. - **Status Indicator Lights**: - **Temperature Control**: The light illuminates when the controller is in temperature-control mode. - **Heating**: The light turns on when the heater is active. - **Mixing**: The light indicates that the mixing process has started. - **Rising**: The light activates when the lifting motor moves upward. - **Lowering**: The light illuminates when the lifting motor descends. - **Upper Limit**: The light flashes when the upper limit switch is triggered. - **Lower Limit**: The light illuminates when the lower limit switch is activated. - **Display Window Area**: - **Temperature Display Zone**: Shows the real-time temperature of the object measured by the sensor. - **Timer Display Zone**: Displays the elapsed mixing time when the mixer is running. As the timer approaches the preset value, this zone will flash. Once the set time is reached, the mixer automatically shuts off, and the lifting motor begins to raise the mixer head. - **Button Input Zone**: - **Temperature Setting Mode**: In standby mode, clicking this button activates the target temperature setting interface. Once inside, the digital display area will blink, allowing you to adjust the temperature value using the corresponding buttons. After completing the adjustment, press the button again to save the setting and exit the temperature setup mode. - **Mixing Time Setting Mode**: Similar to the temperature setting mode, this button activates the mixing time adjustment interface. Here, the timer display area will blink, enabling you to modify the preset mixing duration. Press the button once more after finishing the adjustment to save the setting and exit the mixing time setup mode. - **Exit Temperature Control Mode**: Press this button to return to the normal operating state. - **Start Mixing**: Initiates the mixing process. The timer starts counting down from the moment mixing begins. You can pause the mixer by pressing this button. - **Manual Timer Reset**: Stops the mixer immediately. - **Three Key Controls for Lifting Motor**: - During the rising process, pressing the "Lower" button is ineffective. First, press the "Emergency Stop" button, then press "Lower." - Conversely, during the descending process, pressing the "Raise" button is also ineffective. In such cases, first activate the "Emergency Stop" button, followed by pressing "Raise." V. Operating Steps: 1. **Preparation**: Once the power is turned on, all components enter their ready state. Begin by pre-setting the mixing time and heating temperature according to the relevant procedures or specific job requirements. Press the "Temperature Control" button to activate the heating system. Within approximately 30 minutes, the inner walls of the pot will reach the desired temperature, making the machine ready for operation. 2. **Loading Materials**: Press the "Rise" button on the control panel, and the stirring head will automatically ascend to its highest position. At this point, carefully pour the preheated mixture into the pot. 3. **Mixing Process**: Press the "Lower" button to lower the mixer to its lowest position, allowing the stirring blades to submerge into the mixture. Then, press the central "Start Mixing" button on the panel, and the stirring blades will begin blending the materials. The mixer will automatically stop once the preset mixing time has elapsed. **Note**: If an emergency arises during mixing, immediately press the "Emergency Stop" button to halt the mixer instantly. To minimize resistance when lowering the stirring blades, start the mixer first before pressing the "Lower" button. 4. **Unloading Materials**: Press the "Rise" button to lift the stirring head to its highest position. Loosen the locking nut using the handle, release the locator, and gently invert the pot 90 degrees by hand to discharge the mixture.Use the material-drawing scoop to remove the mixed material, allowing it to fall onto the mold via the sliding plate, and then prepare the sample as needed. 5. Cleaning: After the mixing process and sample preparation are complete, turn off the power supply and thoroughly clean the machine. Pay special attention to ensure that no asphalt residue or debris remains on the heating pot, sliding plate, or搅拌桨 (stirring paddle). 6. Maintenance and Care: 1. Regularly lubricate the lead screw and guide shaft of the lifting mechanism with grease. 2. Replace the lubricating oil in the mixer’s gearbox once a year. 3. If the machine will be stored for an extended period, cover it completely to prevent dust from entering. 4. Protect exposed electrical wires carefully—avoid applying any direct pressure, piercing them with sharp objects, or letting heavy items fall on them. 7. Precautions: 1. When the heating pot reaches the set temperature, there will typically be a brief overshoot phase. This occurs because, even after the heater stops supplying heat, the pot continues to absorb residual warmth from the heater itself. As a result, the temperature may briefly rise further before stabilizing. 2. When testing the temperature control system, place a suitable amount of heating material inside the pot—for example, stones, sand, or water—to facilitate even heat transfer from the pot’s surface to the material. This helps minimize temperature overshoot. Without this step, the pot’s temperature might spike far above the preset level, leading users to mistakenly believe the control system is malfunctioning. 3. Temperature Accuracy: The temperature sensor on the controller measures the temperature at the outer surface of the heating pot, which may slightly differ from the actual temperature of the material located closer to the pot’s center. This discrepancy is normal; users should always rely on the preset temperature setting during operation. 4. During storage and transportation, the instrument may inevitably come into contact with humid air, potentially reducing its electrical insulation performance—especially in the case of the heater, where the decline could be more pronounced. At the initial stage of powering up, users might experience mild tingling sensations due to induced currents. However, these effects usually subside within a few minutes once the heater is turned on. To avoid any risks, ensure the device is properly grounded by connecting it to the grounding hole on the power outlet. Failure to do so will result in full responsibility for any consequences. 5. Lubricate the lifting rod regularly with grease—at least once per shift. Spare parts include one lifting timing belt (installed on the lifting rod inside the machine casing). Additional required components are the material-drawing scoop and the discharge sliding plate. 6. Always connect the machine to a dedicated ground wire!!! While the machine is operating: Never insert your hands or any foreign objects into the heating pot to prevent accidents!!!