Screw fans and Roots fans are common types of compressors in the industrial field, providing stable air pressure and flow for various industrial and commercial applications. Here is a detailed comparison between these two types of fans:
1、 Similarities
1. The purpose is the same: both screw fans and Roots fans belong to positive displacement fans, and their ultimate goal is to provide a stable pressure and flow output to meet various industrial and commercial needs.
2. Industrial applications: These two types of fans are widely used in various industrial fields such as sewage treatment, pneumatic conveying, and pneumatic circulation.
3. Continuous operation: Both screw fans and Roots fans are designed for long-term continuous operation to meet the continuous needs of industrial production.
4. System configuration: During operation, these two types of fans usually require corresponding control systems and devices to ensure stability and performance.
5. Maintenance necessity: In order to maintain long-term stable operation and efficiency, regular maintenance of both types of fans is particularly important.
2、 Difference
1. Working principle:
Roots blower: generates airflow by relative motion of two or more rotating blade rotors within a cylinder. When the rotor rotates, the cavity continuously sucks in air and discharges it outward, thereby generating airflow. Roots blower belongs to the "external compression" type, with no volume change during the conveying process and no internal pressure change (relying on pipeline back pressure).
Screw fan: By rotating the screw inside the casing, the working volume alternately expands and contracts, thereby inhaling gas and increasing pressure. Screw fans belong to the "internal compression" type, and the increase in pressure depends on the change in the internal volume of the host chamber.
2. Pressure range:
Roots blower: mainly suitable for medium and low pressure environments, with a pressure range usually between 0.1 and 1 bar.
Screw fan: can generate higher pressure, usually up to 2 to 10 bar, which is very suitable for occasions that require higher pressure.
3. Traffic stability:
Roots blower: Due to the influence of centrifugal force, its flow pulse is large, which may cause intermittent noise and vibration, so the flow stability at the outlet is not as good as that of screw blower.
Screw fan: The airflow is smoother, the continuity is excellent, the leakage is less, and the pressure pulse is low, making it very suitable for occasions with strict requirements for flow stability.
4. Noise and vibration:
Roots blower: Due to the design of its rotating components, it typically produces high levels of noise and vibration, up to approximately 110-120 decibels.
Screw fan: relatively quiet, with small vibration amplitude, very suitable for places with strict noise restrictions, and its noise level is usually maintained at around 60-85 decibels.
5. Maintenance cost:
Roots blower: The maintenance cost is relatively low, but the high-precision operation requirements may increase the difficulty and cost of maintenance. In addition, the failure rate during long-term operation is relatively high, so a configuration of one in use and one backup is often adopted.
Screw fan: Although its initial investment is relatively high, in the long run, its energy consumption and maintenance costs are relatively low. Especially as the usage time and equipment pressure gradually increase, the advantages of screw fans become increasingly apparent.
6. Efficiency:
Roots blower: Under standard operating conditions, its efficiency may be affected by gas reflux and leakage, resulting in relatively low efficiency.
Screw fan: Due to the use of internal compression technology, it has high working efficiency and stable gas supply. Especially during high-pressure work, its thermal efficiency is relatively high.
7. Lifespan:
Roots blower: simple structure, usually has a long service life. But when working in a high-pressure environment, there may be a risk of damage.
Screw fan: Although its complex structure leads to increased costs, proper maintenance can ensure that it has a longer service life.
3、 Application scenarios
1. Roots blower: more suitable for situations with high flow rate and low pressure requirements, such as aeration tanks in sewage treatment.
2. Screw fan: More suitable for applications that require high pressure and stable airflow, such as gas compression in chemical processes.
In summary, both screw fans and Roots fans have their own advantages, and the decision should be made based on the specific application requirements and scenario conditions.
