The application range of water ring (water cup) vacuum pump is very wide, and the vacuum degree can exceed -30Kpa. However, due to the small air volume of a single machine, it is not commonly used in vacuum cleaning systems.

Roots blower is widely used in positive pressure airflow transportation, but usually a negative pressure value of -30Kpa or above is required in vacuum cleaning systems, and the vacuum degree of ordinary Roots blower cannot meet it.

The air ring (volute) fan has been widely used in vacuum cleaning systems, and the technology is also quite mature. It is cheap but has high heat generation. During normal operation, the shell heats up and the temperature is around 120 degrees Celsius, so the surrounding environment needs good ventilation to cool down. The upper limit of negative pressure value for air ring fans is usually -30Kpa.

Multi-stage Centrifugal Fans usually have 5-stage or 7-stage compression and high negative pressure values. When facing high negative pressure requirements above -40Kpa, multi-stage centrifugal fans are usually selected. Advantages: A single fan has high air volume, high negative pressure value, and stable operation. Disadvantage: The price is expensive. Usually, temperature monitors and vibration monitors are required to monitor the operation status of the fan at any time. Fan selection should be based on the required airflow, negative pressure and operating conditions.

1Kg (kg)=0.1Mpa (megapascals)=100Kpa (kilopascals)=100000pa (pascals)=1bar (bars)=1000mbar (millibars)
1000L/min (liter/minute)=1m3/min (cubic meter/minute)=60m3/h (cubic meter/hour)=60CMH

1.1. For example, blowing through the mouth is positive pressure, while inhaling through the mouth is negative pressure.
1.2. Therefore, when the fan blows air into the dust collector, it is a positive pressure filtration. For example, when conveying materials through airflow, most of the options are for a positive pressure system.
1.3. The fan draws air from the dust collector, which is negative pressure filtration, such as vacuum cleaning and vacuum feeding. The negative pressure system is selected.

2.1. For example, when blowing through the mouth, it is easy to blow down an empty cola bottle that is 20 centimeters away.
2.2 When inhaling through the mouth, do not lift up an empty cola bottle that is 10 centimeters away.
2.3 Therefore, the effectiveness of vacuum cleaning depends on the distance between the vacuum broom and the ground. The closer it is to the ground, the greater the suction force and the better the cleaning effect.
2.4 Airflow conveying can choose either positive or negative pressure airflow. However, positive pressure conveying is usually chosen because when the same force is generated, it can consume energy, and positive pressure is lower than negative pressure.
2.5. When conveying with positive pressure airflow, the material thickness of the shell of the dust collector is thin, while when conveying with negative pressure airflow, the material thickness of the shell of the dust collector is thick.

3.1 For example, blowing through the mouth won't break the cola bottle, while inhaling through the mouth can deflate the cola bottle.
3.2. Therefore, dust collectors used for vacuum negative pressure need to withstand pressure and prevent suction collapse, and the wall thickness cannot be cut corners.
3.3. With the same wall thickness, cylindrical boxes are more resistant to negative pressure than square boxes. Therefore, the cylinder of vacuum dust collectors is usually designed as a cylindrical shape.

4.1. When the cleaning valve is completely closed or the pipeline is blocked, the high negative pressure fan faces the risk of pressure suppression and burning.
4.2. To prevent pressure buildup, a pressure relief valve is usually installed above the dust collector or a bypass pressure relief valve is installed on the main pipeline before the fan inlet.
4.3. After instrument detection, feedback data is sent to the PLC. The PLC program makes judgments based on the feedback parameters and transmits instructions to enable the pneumatic valve to perform opening and closing actions.
4.4. When the cleaning valve is completely closed, the pressure relief valve will automatically open, extracting wild wind from the environment and releasing pressure, effectively protecting the vacuum fan.

5.1. For relatively low dust loading, the flat bag filter stage may be sufficient when properly selected.
5.2. For higher dust loading or continuous operation, cyclone pre-separation can be added upstream of the flat bag collector.
5.3. An optional HEPA final filter can be added where higher outlet air cleanliness or additional protection of downstream equipment is required.
5.4. The actual filtration stages should be selected according to dust concentration, particle characteristics, operating time and required outlet air quality.
5.5. Differential pressure monitoring can be used to indicate abnormal filter resistance and support maintenance or alarm functions.

6.1. Conveying velocity should be selected according to the dust characteristics so that material does not accumulate in the pipeline.
6.2. Main and branch pipe diameters should be determined from the required airflow, conveying velocity and pressure loss.
6.3. DN40 and DN50 terminal connections are commonly used for industrial vacuum cleaning, but the final size depends on the application.
6.4. For conductive or combustible dust applications, bonding and grounding measures should be considered according to the applicable safety requirements.

7.1. A frequency converter can provide controlled starting and operating adjustment where compatible with the selected vacuum fan.
7.2. The permitted frequency range should follow the fan and motor operating limits.
7.3. Excessive speed adjustment can move the fan away from its intended operating range, so the control strategy should be matched to the fan performance curve.

8.1. Offline dust discharge can be suitable for intermittent operation or relatively low dust loading.
8.2. In an offline arrangement, collected material is discharged after the vacuum system is stopped or isolated.
8.3. For continuous operation or higher material loading, an online dust discharge arrangement can be configured.
8.4. Double-stage airlock or discharge valves can be used to reduce air leakage while material is discharged.
8.5. The appropriate arrangement depends on dust loading, operating time and process requirements.

Usually, stainless steel pipes or carbon steel pipes can be used.

Pipeline wall thickness should be selected according to pipe diameter, material, design vacuum level, support spacing and mechanical loads. The pipeline must have sufficient strength to resist deformation under the specified negative pressure.

3.1. Vacuum pipelines should be designed to minimize air leakage so that the required negative pressure can be maintained.
3.2. Welded joints or suitable sealed connections can be used according to the pipe material and installation requirements.
3.3. Valves and fittings should be suitable for negative pressure service.
3.4. Terminal connection sizes such as DN40 or DN50 can be selected according to the required airflow and cleaning tool.
3.5. Flexible vacuum hose should have sufficient strength to resist collapse under the system vacuum level.

Welding steel wire mesh or a few steel wires above the suction port of the terminal pipeline can effectively prevent plastic bags and other debris from being sucked into the pipeline.

Collection of water or wet material requires a suitable liquid separator or water-removal device upstream of the main filter. The configuration should be selected according to the amount of liquid and the collected material.

A debris separator or collection bin can be installed upstream of the main vacuum unit when large objects may enter the suction line. The separator helps prevent large debris from reaching the filter and vacuum generating device.

For combustible dust applications, the complete system requires a dust hazard assessment and suitable explosion prevention or protection measures according to the dust properties, installation conditions and applicable standards. Required devices and certified components should be selected for the specific project.

Yes. Other vacuum generating technologies may also be considered. Selection depends on the required airflow, negative pressure, energy efficiency, operating environment and process requirements.