Hermetic and semi-hermetic compressors demonstrate improvements in compressor designs over the years. These compressors improved productivity and simplified maintenance. However, although both compressors simplify advanced industrial processes, they also have glaring differences.
The Hermetic Compressor
A hermetic compressor or sealed compressor features welded steel shaft that includes the compressor and an electric motor. The shaft is enclosed, which makes hermetic compressors leakproof.
However, don’t expect to find hermetic compressors in large-scale industrial processes. These are perfect for small motor compressor needs, such as an AC compressor, home freezer, domestic refrigerator, and water cooler.
Advantages of Hermetic Compressors
- The compressor and motor are closed in the steel casing, which is air-tight and leakproof. As a result, gas leaks are rare for hermetic compressors, and you don’t need a crankshaft seal.
- Hermetic compressors are compact and require small storage spaces.
- The installation process is straightforward.
- The compact size makes it portable. In addition, you can transfer the compressor and motor as a single unit.
- Lubricating oil is available in the enclosed shaft, making lubrication easy.
- Hermetic compressors are less noisy and emit less vibration.
- The enclosed motor and compressor make lubrication simple.
- The maintenance is cost-effective because hermetic compressors require less maintenance.
Disadvantages of Hermetic Compressors
- The compressor may require less maintenance, but it is not easy to conduct maintenance. All the moving parts are enclosed and inaccessible. You must separate the joints to clean and repair the compressor.
- Hermetic compressors run only on electric power sources, which can be limiting. However, electric motor manufacturers in India are developing new designs to minimise power consumption.
- The compressors are not ideal for large-scale industrial processes.
- Burnout or the presence of moisture can damage the winding motor, causing a system breakdown.
Semi-hermetic compressors are also enclosed, but the casing uses bolts instead of the complex welding in hermetic compressors. It also includes a crankshaft seal that rotates to increase gas pressure and reduce volume.
Advantages of Semi-Hermetic Compressors
- The cast iron casing is bolted to the shaft, meaning you can remove it without tearing the compressor apart.
- Semi-hermetic compressors are reliable for large-scale industrial applications. In addition, you can fine-tune semi-hermetic compressors to match the industrial demands.
- Maintenance is easy because you can access the enclosed parts for repair. Additionally, maintenance is cost-effective because you can repair broken-down parts.
- These compressors are durable.
Disadvantages of Semi-Hermetic Compressors
- Semi-hermetic compressors are prone to oil leakage.
- Contaminants can infiltrate the casing, which destroys the systems.
- You need enough space to store a semi-hermetic compressor.
Major Differences between Hermetic and Semi-Hermetic Compressors
- Maintenance is challenging for hermetic compressors compared to semi-hermetic ones due to the enclosure method. If the former breaks down, you’ll need to replace the entire system because repairs are impossible.
- Hermetic compressors are completely leakproof, but semi-compressors can experience refrigerant leaks.
- Semi-hermetic compressors are perfect for industrial processes, but hermetic compressors are ideal for compact and domestic refrigeration systems.
- Hermetic compressors circulate oil through centrifugal force, and semi-hermetic compressors use an oil pump.
Generally, both compressors are highly-effective. However, you should analyse your needs and intended use before selecting a compressor. If all else fails, contact a professional who has experience in compressor manufacturing.