Difference Between Screw and Scroll Compressors

Deciding which type of air compressor to install can be daunting for engineers, technical experts, and project installation executives.

The two fundamental types of air compressors are: Positive displacement and dynamic. The most popular of these are rotary screws, reciprocating air, axial, centrifugal, and scroll compressors. Each air compressor type comes with its own pros and cons list.

When buying air compressors, you should think about several factors. These include your facility needs, location, pressure dew point, and power costs. So, doing your homework correctly would help before installing an air compressor in your facility.

1. Ultra-quiet Operation: If you're looking for a compressor that's not just quiet—but ultra-quiet, scroll compressors are your best option. Scroll compressors offer noise levels as low as 48 dBA.
2. Ideal for Indoor Settings: The compact design of scroll compressors minimizes and saves floor space, which can be used for other purposes. Several businesses keep their scroll compressors in the closet, so you don’t have to create a dedicated room for your air compressor.
3. Energy Efficiency: The technology used within scroll compressors makes them energy efficient. The system shuts down compressor pumps that are not required and automatically adjusts pressure settings. This saves electricity by not producing unwanted air and increases the machine's life.

1. Difficult to Repair: The biggest drawback of the scroll compressor is that it is not easily repairable. The complex design makes it difficult to inspect and clean. One of the inter-fitting scrolls is fixed and can’t be dismantled.
2. High Manufacturing Costs: The manufacturing of scroll compressors involves high-end machinery and precise centering assembly technology, which pushes up the manufacturing cost and, consequently, the price.
3. Gas Leakage: A certain gap is deliberately kept between the moving and non-moving components to achieve sealing. This leads to gas leakage, which restricts the scroll compressor from achieving a larger compression ratio, contributes to unnecessary power consumption, and adversely impacts the air compressor system in the long run.
4. Additional Accessories Needed: Even though scroll compressors manage liquid better compared to other air compressor systems, they still need additional accessories such as crankcase heaters and suction line accumulators for added protection, which adds to the purchasing cost.

1. Supports Extreme Weather Conditions: Rotary screw compressors, support extreme high and low weather conditions. They even function where other chemicals are prohibited to avoid hazardous situations.
2. Fewer Components: Unlike other compressors, rotary screw compressors comprise 70% fewer components, making the maintenance procedure easier and reducing maintenance costs.
3. Quiet Operation: Despite massive airflow, rotary screw compressors produce less noise, thanks to the noise-dampening technologies embedded in them, which ensures a quiet work environment.
4. Less Heat Production: Rotary screw compressors produce less heat, contributing to the system’s longevity. They also utilize less oil, ensuring sufficient oil for the compression chamber to cool the machine, lubricate the moving parts, seal, and dissipate noise.

Still unsure about the difference between a screw and scroll compressor in practical terms? Here's a breakdown of where each excels:

• Use screw compressors for heavy-duty industrial applications like automotive, brewing, food packaging, aerospace, and construction where continous operation is essential.
• Use scroll compressors in quieter, indoor environments like dental clinics, laboratories, and medical facilities. Scroll compressors are also preferred in residential air-conditioning systems and medical HVAC systems.

At Atlas Copco, we supply both screw and scroll compressors that will decrease operational costs and increase uptime! Knowing the difference between screw and scroll compressors is the first step. Our experts will help you pick the best model for your production.