Accumulator with pickup tube

Abstract

A suction accumulator for refrigeration or air-conditioning system use, especially for automotive air conditioning system use, which comprises a “pickup tube” to withdraw liquid from a reservoir of the accumulator to return oil to the compressor. The accumulator has a deflector with an outlet tube, to help ensure that fluid does not flow directly from the inlet opening to the outlet opening of the accumulator. The relatively narrow second portion of the outlet tube is closer to the outlet opening than the first portion. The pickup tube is secured in communication with the relatively narrow second portion and optimises the oil return function, minimises restriction to refrigerant flow, maximises effective and actual reservoir volume, and minimises the amount of liquid delivered to the compressor at switch-off. Incorporating an electric heating element or a heat exchanger for engine coolant or exhaust allows the accumulator of the present invention to function as the evaporator when the refrigeration system is used in heat pump mode for heating applications.

Description

[0001] This application is a conversion from U.S. Provisional application No. 60 / 512,102.FIELD OF THE INVENTION [0002] The present invention relates to a new and improved suction accumulator for use in a refrigeration system, including air-conditioning (A / C) or heat pump systems, and may be used in an air-conditioning or heat pump system of a motor vehicle. BACKGROUND OF THE INVENTION [0003] 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 or valve divides the system into high and low-pressure sides. The liquid on the high-pressure side passes through the orifice or valve and turns into a gas in the evaporator as it picks up heat. (Some systems operate in “transcritical” mode, where the hot refrigerant is merely cooled in the high side heat excha...

AI Technical Summary

Benefits of technology

[0020] An embodiment of the present invention minimizes or reduces the pressure drop by using a deflector to manage the flow of fluid and by using a pressure reduction at a restriction within a conduit through the deflector. The pressure reduction helps lift liquid (oil or mostly oil) up a small tube or passage (a “pickup tube”) where the liquid is be entrained into the outlet flow of gaseous refrigerant. The pickup tube is relatively small in diameter (occupying much less internal volume than a conventional J-tube) which therefore increases the effective internal volume of the accumulator when combined with a deflector (where the deflector helps to minimize or reduce reservoir churning and splashing).

[0031] Electric heaters may be used to provide supplementary heat. A cost effective option is to install an electric heater in the accumulator reservoir to supply heat for evaporation. Since the heat delivered by the heat pump is the sum of the heat put in by the compressor plus the heat put in by the evaporator, the heat put in to evaporate the refrigerant is less than the heat evolved by the heat pump, and therefore less electricity would be required to get sufficient supplementary heat with this method. By using such a heat pump, a smaller alternator, less wiring, and fewer controls would be required than to provide direct electric supplementary heating. Hence in one embodiment, it is advantageous to have an accumulator with a large open reservoir volume that can effectively house heat exchanger coils or an electric heater to provide the evaporator function in heat pump mode.

Problems solved by technology

However even when the outlet is at or near the bottom of the accumulator, a riser tube is typically required to prevent the reservoir from being emptied at switch-off (to avoid filling the lines or the compressor with liquid and causing undesirable compressor slug at start up).

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