REFRIGERANT ACCUMULATOR WITH LIQUID SEPARATOR

Abstract

A refrigerant accumulator for refrigerant circuits having a container with an inlet for a two-phase mixture and an outlet for the refrigerant vapor. The accumulator includes a baffle provided as a separator in the upper part of the refrigerant accumulator. The baffle includes means for the collection of liquid refrigerant, by which the liquid refrigerant is leadable into the lower region of the refrigerant accumulator.

Description

BACKGROUND

1. Field of the Invention

The invention relates to a refrigerant accumulator for use in refrigerant circuits and more particularly to a refrigerant accumulator with a liquid separator.

2. Related Technology

Refrigerant accumulators are used in refrigeration systems or heat pumps which work on the principle of cold vapor process, and are placed downstream of the evaporator. The refrigerant accumulator functions to separate that portion of the inflowing two-phase mixture which has not yet been liquefied from the gaseous portion. To do this, it uses a suitable liquid separator. The separated liquid refrigerant and, if present, the liquid refrigerator oil is accumulated or temporarily stored, respectively, in the accumulator.

Various embodiments of refrigerant accumulators are known in the art. In U.S. Pat. No. 6,564,575, the refrigerant flow entering the refrigerant accumulator is frontally led onto a baffle plate. The liquid portion of the refrigerant flow is then directed to the inner wall of the accumulator where it adheres to the inner wall due to inertia forces and wetting effects and flows downward into the storage region of the accumulator.

According to the teachings of U.S. Pat. No. 6,430,958, a refrigerant accumulator is disclosed in which the liquid portions of the refrigerant are led tangentially to the inner wall, eventually reaching the storage region of the accumulator.

Various disadvantages are inherent in the state-of-the-art. Particularly serious disadvantage is that in an environment with temperatures above the saturation temperature of the inflowing refrigerant, heat input into the accumulator will occur due to the temperature gradient. If the container wall of the accumulator is a component of the mechanical separator, the heat input may be excessive. Also if the accumulator is almost empty, a thin film of liquid refrigerant develops at the inner wall of the container creating ideal conditions for evaporation processes, or heat adsorption by the refrigerant.

In U.S. 2005/0081559, a refrigerant accumulator is shown in which a baffle plate is used below the inlet of the two-phase mixture. The liquid components hit the baffle plate, adhere to it and flow along the baffle plate to the lower border of the baffle plate. At the lower border of the baffle plate drops of liquid refrigerant form and then drop down, due to gravity, into the lower region of the container where they are intermediately stored.

It is disadvantageous in the above mentioned state-of-the-art that the flows of liquid and the gaseous refrigerant, after separation, are led such that they cross each other. Therefore, the gaseous flow inevitably drags a portion of the separated liquid displacing it to the outlet of the accumulator. This liquid bypass results in low separation efficiency. In addition, the danger of piston impact increases in refrigerant piston compressors when the liquid phase of the refrigerant, in form of droplets, reaches the compressor.

The disadvantages of the known refrigerant accumulators increase the circulating refrigerant mass flow, but do not increase the useful refrigerating or heating capacity of the machine. An increase of the refrigerant mass flow, however, has an unfavorable effect of increasing the power input of the plant. Accordingly, the coefficient of performance (COP) or the efficiency of the machine gets worse.

SUMMARY

The present invention provides a refrigerant accumulator with a liquid separator such that a high separator efficiency is achieved, while refrigerant mass flow is minimized by minimizing the heat input into the separated liquid refrigerant.

According to the invention, above limitation and drawbacks are sought to be overcome by a refrigerant accumulator having a container with an inlet for the two-phase mixture and an outlet for the refrigerant vapor. A baffle is provided as a separator in the upper part of the refrigerant accumulator. According to the invention, the baffle is provided with means for collecting and leading the liquid refrigerant into the lower region of the refrigerant accumulator.

In an advantageous embodiment of the invention, the means for collecting the liquid refrigerant is arranged at the lower border of the baffle. In a particularly advantageous embodiment, the means for collecting the liquid refrigerant is configured as eaves in gutter form. Advantageously, the eaves are provided with a region for collection of liquid refrigerant and are configured with a slope towards the region of collection. This ensures that the liquid refrigerant separated on the baffle is collected at the eaves and led off towards the region of collection by gravity.

In an advantageous embodiment of the refrigerant accumulator, an exhaust pipe for the refrigerant vapor is configured to be without thermal contact with the container wall, whereby advantageously the collection region of the baffle is connected to this exhaust pipe. The liquid refrigerant therefore comes to the collection region over the means for collecting the liquid refrigerant, and from the collection region flows on the exterior of the exhaust pipe downward into the accumulator region. It is particularly advantageous to design the exhaust pipe in a J-shape, whereby the lower opening of the exhaust pipe is located below and underneath the dome-like baffle, which is hit by the two-phase mixture from above.

In alternative embodiments of the invention, the baffle is configured to be half-spherical, parabolic or cone-shaped.

The concept of the invention resides in that the exhaust of the gaseous refrigerant is arranged such that dragging of refrigerant droplets by the refrigerant vapors is largely prevented by design, and further, that the heat input into the liquid refrigerant, increasing the mass flow, is reduced by specific collecting and leading off the liquid refrigerant.

One configuration and function of a refrigerant accumulator according to the invention can generally be described as follows: the inlet of the refrigerant accumulator for the two-phase mixture is located above the baffle. The liquid components of the inflowing refrigerant contact the baffle and adhere to it by adhesion forces. Hence, both phases are separated from each other. The gaseous phase flows around through an annular gap between the baffle and the inner wall of the container and into the container region below the baffle, where the gaseous phase is drawn off underneath the baffle by the exhaust pipe.

The liquid phase flows across the convex surface of the baffle downward into a catching and flow-off gutter, generally referred to as the means for collecting the liquid refrigerant. In this way, no eaves, in the traditional sense, are formed at the lower border of the baffle over which the liquid refrigerant would drop into the lower region of the container, along the whole edge of the baffle. The liquid refrigerant and liquid oil collected in the gutter, due to sloped arrangement of the gutter/baffle, flow toward a leg of the J-shaped exhaust pipe. At the exhaust pipe, the gutter is open so that the liquid adhering to the outer surface of the exhaust pipe can flow downward along a portion of the exhaust pipe into the lower storage region of the accumulator, without wetting the inner surface of the container. As a result, heat input into the accumulator is kept low because, for a low refrigerant level, heat can only enter the accumulator by convection but not by refrigerant evaporation. Also, dropping liquid is prevented from crossing with the gas flow and being dragged by the gas flow into the exhaust.

As seen from above, the invention has various advantages. Particularly advantageous is that the liquid separator has a high separation efficiency since after phase separation the liquid and gas flows do not cross each other. In this way, the gas, or refrigerant vapor, leaving the refrigerant accumulator towards the refrigerant compressor is effectively prevented from containing liquid droplets of the two-phase mixture that flows into the refrigerant accumulator itself.

With this, the operational safety of a refrigeration plant or a heat pump, respectively, is effectively increased since the danger of piston impacts caused by liquid entering the compressor is minimized.

Another advantage of the present invention is in that the heat input into the accumulator is minimized because the inner container surface is not used as part of the liquid separator and, hence, no heat input worth mentioning enters the accumulated liquid refrigerant over this container surface.

The advantageous effects of the present invention are reflected in an increase of the COP of the refrigeration machine or heat pump. This occurs because the refrigerant mass flow of the plant is not increased as a result of the operation of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details, features and advantages of the present invention are made more apparent through the detailed description of the various of embodiments, with reference to the accompanying drawings, in which:

FIG. 1 is a sectional view of a refrigerant accumulator in accordance with the present invention;

FIG. 2a is a schematic drawing of a baffle. similar to a hemisphere, with means for collecting the liquid refrigerant as might alternately be employed in the refrigerant accumulator of FIG. 1;

FIG. 2b is a schematic drawing of a hood-like baffle with means for collecting the liquid refrigerant; and

FIG. 2c is a schematic drawing of a circular cone-like baffle having means for collecting the liquid refrigerant.

DETAILED DESCRIPTION

Referring now to the drawings, in FIG. 1 a refrigerant accumulator 10 with J-shaped exhaust pipe 12 is shown in sectional view. The accumulator 10 includes a container 13 having a side wall 14 delimited by an upper border in the form of a cover plate 16 with connections and a lower border in the form of a bottom plate 18.

The represented embodiment shows a circular, cylindrical side wall 14. The cover plate 16 has an inlet 20, such as a nipple, for the two-phase mixture, as well as a connection 22, such as an opening, for the outlet 24 of the refrigerant vapor. The inlet 20 of the two-phase mixture is arranged approximately central at the cover plate 16 so that the two-phase mixture enters the container 14 from above. The entering two-phase mixture is provided onto a baffle 26 from above, which in the embodiment shown is being hood-like or hemispherical, generally like an umbrella. The outer diameter of the baffle 26 is provided such that an annular gap is created between the baffle 26 and the container side wall 14.

At its lower perimeter, the baffle 26 is provided with a means for collecting the liquid refrigerant 28, which is in the form of eaves. The eaves 28 themselves are configured gutter-like, with an up-turned edge, so that the liquid refrigerant does not drop uncontrollably from the edge of the baffle 26. The gutter-like eaves 28 are arranged around the baffle 26 and slope downward toward one side and at the lower end is provided with a collection region 30 for the liquid refrigerant. The collection region 30 for the liquid refrigerant is in connection with the exhaust pipe 12.

The exhaust pipe 12 itself does not contact the container 13, with the exception of the connection 22 at the outlet 24 for the refrigerant vapor. This largely separates the exhaust pipe 12 from the container 13 in thermal respects so that the heat input into the liquid refrigerant is minimized.

The exhaust pipe 12 is reversely bent and provided in its upper end being the outlet 24 in the cover plate 16 of the container 13 and, at its other end, with the exhaust inlet opening 32, which is arranged in an interior cavity 34 within the underside of the hood-like baffle 26.

Therefore, the two-phase mixture flows from the inlet 20 onto the baffle 26. On the baffle 26 the liquid droplets, after wetting the baffle 26, are separated from the mixture and flow towards the periphery of the baffle 26 where they are collected in the eaves 28. Because of the slope of the eaves 28 the liquid refrigerant then flows in the eaves 28 to the collection region 30 where the liquid component of the two-phase mixture concentrate.

The collection region 30 for liquid refrigerant is in contact to the exhaust pipe 12 so that the liquid refrigerant flows over the baffle 26, the eaves 28 and the collection region 30 towards the exhaust pipe 12. Over the connection between the collection region 30 and the exhaust pipe 12 the liquid refrigerant flows on the outside of the exhaust pipe 12 downwards to the refrigerant accumulator region 36.

Advantageously, the liquid refrigerant does not flow along the relatively warm side wall 14 of the accumulator 10 downwards into the refrigerant accumulation region 36, but instead flows on the relatively cold exhaust pipe 12, through which the refrigerant vapor passes towards the compressor. In this way the refrigerant mass flow is not additionally increased by evaporating refrigerant and the efficiency of the refrigeration process is, therefore, higher compared with other refrigerant accumulator concepts.

In the FIGS. 2a to 2c alternative embodiments of baffles are exemplarily shown. The baffles are generally hood-like and are, uniting them according to the concept of the invention, provided with gutter-like eaves as the means for collecting the liquid refrigerant separated on the baffle. According to the profiles represented, FIG. 2a shows a hemispherical embodiment of a baffle 126 with a gutter-like eaves 226. In FIG. 2b, a parabolic shape baffle 226 with a gutter-like eaves 228 is shown. In FIG. 2c, a circular cone-like shape is provided of the baffle 326, with a gutter-like eaves 328.

While the eaves 28 et al. are shown as being in a gutter-like configuration, one skilled in the art will appreciate that various shapes for eaves could be provided without departing from the spirit of the present invention. A common aspect consists in that the eaves, the means for collecting and leading off the liquid refrigerant, are provided at the perimeter of the baffles and prevent the liquid refrigerant on the baffle from dropping off immediately at the border of the baffle and being dragged as drops by the refrigerant vapor under correspondingly unfavorable flow conditions.

As a person skilled in the art will readily appreciate, the above description is meant as an illustration of implementation of the principles this invention. This description is not intended to limit the scope or application of this invention in that the invention is susceptible to modification, variation and change, without departing from spirit of this invention, as defined in the following claims.

Claims

1. A refrigerant accumulator with a liquid separator for refrigerant circuits comprising:

a container defining a hollow interior and having an inlet for a two-phase mixture and an outlet for refrigerant vapor;

a baffle provided in an upper part of the hollow interior, the baffle having a collector configured to receive and direct the liquid refrigerant into a lower region of the refrigerant accumulator.

2. The refrigerant accumulator of claim 1 wherein the collector is located at a lower peripheral border of the baffle.

3. The refrigerant accumulator of claim 1 wherein the collector is configured as an eaves gutter.

4. The refrigerant accumulator of claim 1 wherein the collector slopes downward towards a collection region.

5. The refrigerant accumulator of claim 4 further comprising an exhaust pipe for the refrigerant vapor, the exhaust pipe being supported by the container so as to be spaced apart from a side wall thereof.

6. The refrigerant accumulator of claim 5 wherein the collection region of the baffle is connected to the exhaust pipe.

7. The refrigerant accumulator of claim 1 wherein the collector slopes downward towards one side of the container.

8. The refrigerant accumulator of claim 1 further comprising an exhaust pipe for the refrigerant vapor, the exhaust pipe being supported by the container so as to be space apart from a side wall so as to have no direct thermal contact therewith.

9. The refrigerant accumulator of claim 8 wherein the exhaust pipe has a J-shape, whereby a lower opening of the exhaust pipe is provided as exhaust inlet opening arranged below the baffle.

10. The refrigerant accumulator of claim 9 wherein the exhaust inlet opening is located underneath the baffle.

11. The refrigerant accumulator of claim 9 wherein the exhaust inlet opening is located within a concavity formed by the baffle.

12. The refrigerant accumulator of claim 1 wherein the baffle is hemi-spherical.

13. The refrigerant accumulator of claim 1 wherein the baffle is cone-shaped.

14. The refrigerant accumulator of claim 1 wherein the baffle is parabolic.

15. The refrigerant accumulator of claim 1 wherein the container includes a cylindrical side wall.