Accumulator with full-flow filtering

Abstract

An accumulator for an air conditioning system is adapted to ensure that any fluid exiting the accumulator has been filtered. Fluid comprising gaseous refrigerant, liquid refrigerant and oil enters the accumulator. Ideally, only gaseous refrigerant and oil will exit the accumulator. According to one embodiment, gaseous refrigerant is substantially separated from liquid refrigerant. Oil is entrained within the gaseous refrigerant. The gaseous refrigerant with the entrained oil is filtered prior to exiting the accumulator. In another embodiment, gaseous refrigerant, which has been separated from the liquid refrigerant, is filtered before the oil is entrained with it. The oil is then separately filtered.

Description

FIELD OF THE INVENTION [0001] The invention relates to accumulators for air-conditioning systems and is particularly concerned with filters for accumulators. BACKGROUND OF THE INVENTION [0002] Closed-loop refrigeration systems conventionally employ a compressor that is meant to draw in gaseous refrigerant at relatively low pressure and discharge hot refrigerant at relatively high pressure. The hot refrigerant condenses into liquid as it is cooled in a condenser. A small orifice, valve, tube, or other restriction divides the system into high and low-pressure sides. The liquid on the high-pressure side passes through the restriction and expands at least partly to gas, hence the general term for the restriction is “expansion device”. Some systems operate in “transcritical” mode, in that the hot refrigerant is merely cooled in the high side heat exchanger, now termed a “gas cooler”, and turns to gas plus liquid as it passes through the expansion device. At low heat loads, it is not poss...

AI Technical Summary

Benefits of technology

[0012] According to one aspect, the invention provides an accumulator for an air conditioner or HVAC system comprising a filter for filtering substantially separated gaseous refrigerant and oil. The filter is adapted to ensure that any fluid exiting the accumulator has been filtered, without greatly impeding flow or adding excessive cost, complexity or components.

[0024] providing filters with minimal effect on accumulator function, size, assembly, installation, cost, or complexity;

[0025] providing filters with a large surface area to provide minimal pressure drop, as flow through the filter can be distributed over the surface area of the filter.

Problems solved by technology

At low heat loads, it is not possible to evaporate all the liquid the compressor is capable of supplying to the evaporator.

However excess liquid refrigerant entering the compressor (known as “slugging”) causes system efficiency loss and can damage the compressor.

However, there are some designs of accumulators that do not use deflectors.

Some refrigerant systems are more susceptible to moisture ingression and damage than others, especially less modern systems.

A consequence of using a suction line accumulator is that compressor oil can become trapped within it.

As compressors in mobile air-conditioning systems are becoming more sophisticated, they are also becoming susceptible to damage from particulate matter entering the compression chambers.

However, these filters are not fine enough for current requirements, nor do they stop particles that originate between the expansion device and the compressor inlet.

However it is well known that the performance of air-conditioning systems deteriorates with decreasing conductance of the lines connecting the evaporator to the compressor, that is, with increasing suction line pressure drop.

Hence installing a suction line filter decreases system performance.

As suggested above, historically, only small filters with a small open area have been installed in fittings, connections, or ports of components (for example on the compressor inlet port), because adding another, separate component to the system would cause an undesirable cost and increase complexity, especially if the component is a large filter in a canister.

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