A compressor is a machine used to supply air or gas at an increased pressure of compressible fluids and gases. It reduces the volume of something (mainly air) and by pressure. The liquid in the compressors is sometimes compressed in many steps to increase discharge pressure. Sometimes, the second stage is physically smaller to accommodate the already compressed gas while not affecting the pressure.
In each stage, the gas is further compressed, and the pressure is increased along with the temperature, where an intercooler isn’t used anywhere between the stages. In this article, we will discuss hermetic compressors and semi-hermetic compressors.
Hermetic Compressors:
In hermetic compressors, the motor is located along with the compressor within a single outer welded steel shell. The best part of a hermetic compressor is that there is little to no leakage. But with this benefit also comes a drawback.
Due to the construction of various components, including the steel shell, performing basic repairs on the hermetic commercial compressors is impossible. This implies that the entire hermetic compressor must be replaced if the unit fails. This leads to pointless and unanticipated losses that cannot be recovered easily.
Damage Prevention Mechanism of Hermetic Compressors:
In hermetic compressors, airtight seals are used to protect all the components so that the central compressor and engine are safe from any kind of damage. Airtight seals also prevent infiltration of different elements like dust, preventing any sort of interference with the operation and hindering liquid slugging or flooding.
Although hermetic compressors usually have a low cost of ownership, the operating noise can be extremely high. Hermetic compressors are more likely to suffer from higher levels of vibrations than other compressors.
You can expect a hermetic compressor to last anywhere between two to five years. The average service length grows with time. If hermetic compressors are not used very often, they may last more than five years. The lifetime of a compressor can also be increased by maintaining the appropriate refrigerant level and implementing many other preventive steps.
Heavy use of hermetic compressors leads to a considerable degradation in their performance and might even lead to the breakdown of the unit.
Hermetic commercial compressors were very common at some point in time. As a result, more and more companies expect the ability to be extremely active in maintenance. As time passed, new developments in technology came into place and have been successful in reducing leakage as well as expanding maintenance.
Semi-Hermetic Compressors or Industrial Compressors
Invented by motor manufacturing companies around the 1940s, the semi-hermetic compressor has seen massive improvements in the last few decades. It is an excellent alternative to hermetic compressors concerning common use. Unlike hermetic compressors, they can be repaired if some key mechanical equipment fails. In addition, it’s not like hermetic compressors, where you have to replace an entire compressor if it fails.
In semi-hermetic conductors, cast iron is used to build the essential parts. The motor and compressor, housed in the same place, can be accessed as and when required. The main advantage of this is that the compressors can be maintained, repaired, or replaced, as some parts malfunction rather than leading to the total failure of the system.
The hermetic compressor and the semi-hermetic compressor came into the picture when open compressed architecture caused a lot of trouble. In the open compressed architecture, the engine and the primary compressor did not receive any sort of protection.
The compressors differ in several ways, one of which is their guiding concept. They fall into one of five categories here:
- Reciprocating
- Rotary
- Scroll
- Screw
- Centrifugal
If a semi-hermetic compressor is maintained well regularly, it is expected to last for more than five years, mainly from eight to ten years. Semi-hermetic compressors that are not used very often last almost up to twenty years.
Semi-hermetic commercial compressors were first used in a large air-conditioning system. After that, they were incorporated into refrigerators, and many brands have adopted this model.
Where are semi-hermetic compressors used?
If you’re looking for budget-friendly options for large-scale refrigeration applications, semi-hermetic compressors are the best choice. But to get maximum output from a semi-hermetic compressor, it must be well maintained at regular intervals and used under operating conditions that are monitored and optimised.
On-Board internal monitoring is also engaged via a range of sensors. Through these sensors, the unit can adapt to changing conditions and perform accordingly, regularly maintain service, and alert every detail about occurring outside the said specifications.
If you want to ensure that the compressor is operating at expected levels, you can perform different types of tests. If you have a good service agreement with your manufacturer or motor manufacturing company, a compressor’s service life can also extend. This agreement will save a lot of money over the coming years.
Conclusion
This was all about hermetic compressors and semi-hermetic compressors. Semi-hermetic compressors fill up all the shortcomings of hermetic compressors and bring in more benefits. In terms of cost, usability, longevity, maintenance, and overall output, semi-hermetic compressors are a great choice.
They have been adopted by many brands and are also growing in popularity. As days pass, technology will improve, and we will see significant advancements in semi-hermetic conductors as well.
