A hydraulic compressor is a type of compressor that is designed to convert hydraulic power to pneumatic power.^[1] It is used across various industries to improve the efficiency of certain types of machinery. Hydraulic compressors have a hydraulic pump to push air through a pipe, which forces a motor to spin. The motor powers the internal air compressor, releasing air in a chamber as a result.^[1] Compressors became more popularized in 1799 when Englishman George Medhurst invented a motorized air compressor as a means for propulsion.^[2] They have technologically advanced to the point where they can achieve greater force and precision than humans.

Uses

Because of the relatively cheap and easy installment of hydraulic compressors, many industries have implemented them into their equipment to effectively work and provide better results. This includes agriculture, automotive, medical, and industrial companies that require engineers or workers to have more output and innovation.

Design

Cost Breakdown

Fig 2: 0: Energy Cost, 1: Compressor Cost, 2: Maintenance Cost (Based on 24/7 operation, $0.08/kWh, full load operation).^[8]

Most of the expenses from integrating a compressor is the energy cost, as depicted in figure 2. The main factors are the type and size of the compressor. That is what determines the utility and power draw of the machine. To be most efficient, the air production capacity should match the air requirements to avoid bottlenecks and unnecessary energy being lost in the form of heat when the air is released.^[8] By optimizing utilization or preventing leakage, companies can increase their profit margins.

The design of the piping can also affect the cost of the system. A pipe structure without sharp corners or dead-heads can help maintain pressure and an efficient passage for compressed air. Designers have to think about the type of material that will be used in the hydraulic system. Aluminum, for example, has a lower weight and corrosion resistance than the more traditional material, steel.^[8] Because it is much lighter than steel, aluminum pipes allow welders and technicians to manufacture and install them easier. The diameter of the pipe is also crucial since smaller diameters tend to have more pressure differential. That would cause more pressure energy to be converted to heat or vibration, thereby decreasing the compressor's lifespan^[9]

Efficiency

To calculate the compressed airflow power, the equation ${\displaystyle W=mRT*ln(\beta )}$ can be used to measure the maximum efficiency of a hydraulic compressor. However, in a real-world scenario, airflow loss needs to be accounted for. This can be done by applying the energy conservation equation for an isothermal flow (assuming water and air have the same pressure and velocity): ${\displaystyle loss=m[RT*ln(P0/P1)-V^{2}/2]}$. Many other factors can also cause the loss of air, such as collision against walls or the friction between water and air bubbles.^[10]

The flow of compressed air produced increases when the mass flow rate of liquid circulating the system also increases. This flow can be calculated only at specific parts of the hydraulic pump, as various configurations can be implemented. Examples of these configurations include a parallel or series pumping arrangement. The pump curve can be defined using a derivation of the quadratic equation: ${\displaystyle Q=-b\pm *\surd (b^{2}-4a(c-H))/2a}$. The equation calculates the efficiency of the pump head or driver, which can be graphed with electrical power consumed to compare hydraulic systems.^[11]

See also

• Compressor

References