How Helical Oil Separators Work?

Helical oil separators offer99 to100 percent efficiency in oil separation with low pressure drop. Upon entering the oil separator, the refrigerant gas and oil fog mixture encounter the leading edge of a helical fighting. The gas/oil mixture is centrifugally forced along the spiral path of the helix, causing the heavier oil particles to spin to the perimeter where impingement with a screen layer occurs. This screen layer serves as an oil stripping and draining medium. The separated oil now flows downward along the boundary of the shell through a baffle and into an oil collection area at the bottom of the separator. The specially designed baffle isolates the oil collection and eliminates oil re-entrainment by preventing turbulence. Virtually oil-free refrigerant gas exits the separator through an exit screen just below the lower edge of the helical fighting. A float activated oil return lave allows the captured oil to return to the compressor’s crankcase or oil reservoir. When the level of oil gets high enough to raise a float, an oil return needle is opened and the oil is returned to the compressor’s crankcase through a small return line connected to the compressor’s crankcase. The pressure difference between the high and low sides of the refrigeration or air conditioning system is the driving force for the oil to travel from the oil separator to the crankcase. The oil separator is in the high side of the system, and the compressor’s crankcase is in the low side. This float operated oil return needle valve is located high enough in the oil sump to allow clean oil to be automatically returned to the compressor’s crankcase .Only a small amount of oil is needed to actuate the float mechanism. This ensures only a small amount of oil is ever absent from the compressor’s crankcase at any given time. When the oil level in the sump of the oil separator drops to a certain level, the float will force the needle valve closed. On larger parallel compressor systems, the oil separator gives the oil to an oil reservoir for temporary storage until a compressor calls for it. The oil reservoir is usually kept at a pressure at about20 psi above the common suction header pressure by a special pressure regulating valve. Many times there may be a combination oil separator/reservoir. In this case, the oil is distributed to each compressor’s oil level regulator at a reduced pressure before entering a compressor’s crankcase.

The accumulator is a safety device. It prevents liquid refrigerant from flowing into the suction line and into the compressor.

Liquid refri8erant, flowing into the compressor, may cause considerable knocking and damage to the compressor. A typical accumulator has the outlet at the top.

Any liquid refrigerant that flows into the accumulator will be evaporated. Then vapor only will flow into the suction line. Since the accumulator is located inside the cabinet, it also provides some refrigeration.

 Not all refrigerating systems have accumulators

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Helical oil separators offer99 to100 percent efficiency in oil separation

with low pressure drop. Upon entering the oil separator, the refrigerant gas

and oil fog mixture encounter the leading edge of a helical flighting. The gas/

oil mixture is centrifugally forced along the spiral path of the helix, causing

the heavier oil particles to spin to the perimeter where impingement with a screen layer occurs. This screen layer serves as an oil stripping and draining

medium. The separated oil now flows downward along the boundary of the

shell through a baffle and into an oil collection area at the bottom of the separator.

The specially designed baffle isolates the oil collection and eliminates

oil re-entrainment by preventing turbulence.