Background Art Many air conditioning, refrigeration and heat pump systems utilize refrigerants to effect heat transfer. Typically, the refrigerant is from a class of fluids known as freon. The heat transfer is effected by compressing a refrigerant in its gaseous state to liquefy it and in the process release heat energy. In the case of refrigeration or air conditioning a heat exchanger dissipates the released heat to an ambient atmosphere. The liquid refrigerant is flowed to another heat exchanger which is in heat absorbing relationship with a space to be cooled. The refrigerant is allowed to expand and vaporize to absorb heat via the second heat exchanger.

In a refrigerator, for example, a compressor unit disposed outside a refrigerated compartment, is used to compress the refrigerant from its vapor state to a liquid state and thereby dispel heat to the ambient atmosphere.

Liquid refrigerant is delivered to a cooling heat exchanger in communication with an atmosphere within the refrigeration chamber. The refrigerant is allowed to vaporize within the cooling heat exchanger and thereby absorb heat from the atmosphere within the chamber.

The systems which use refrigerant for heat transfer from time to time must be serviced by a process known as charging. With the charging process, a manifold is connected to the system being recharged and to a source of refrigerant. When the system is being fully recharged it typically is evacuated and then the refrigerant is delivered in liquid form via the manifold to the system. For top-off, the refrigerant is charged in its vapor state.

Heretofore, such recharging has typically used a manifold for recharging. The manifold has high side and low side outlets which are

respectively connected to the high or liquid side and the low or vapor side of a compressor. For primary recharging, when the recharging is done properly, the low side outlet is closed, a source of liquid refrigerant is connected to an inlet to the manifold and the high side is charged to a desired level. Once the primary recharging has been completed, the high side or liquid outlet is closed and the vapor side is opened. Refrigerant is fed through a vaporizing restrictor connected in series with the manifold. The compressor is energized to cause it to liquefy vapor from the low side and deliver liquid refrigerant to the high side. Top-off is then achieved by delivering vapor to the low side of the system being charged.

Accordingly, there has been a need for a recharging manifold system which can effect primary recharging utilizing liquid refrigerant and top-off with vaporized refrigerant without use of a manifold and a restrictor in series with it.

Summary of the Invention In its preferred form, a mechanism embodying the present invention includes a manifold. The manifold has a housing defining an inlet and two outlets. One of the outlets is intended to be connected to the so-called high side of a system being charged, while the other outlet is intended to be connected to the so-called low side. The high side is that portion of the system being charged in which refrigerant is contained in its liquid state, while the low side contains refrigerant in its vapor state.

The manifold has an inlet for connection to a source of refrigerant which under current mandates is always in a liquid state. Internal passages in the manifold communicate the supply inlet with a state control arrangement embodying novel features of the present invention. Other internal manifold passages communicate the arrangement with the outlets. A pair of outlet control valves are provided, each associated with a different one of the outlets for selectively establishing and interrupting communication between manifold passages and the associated outlet.

The state control arrangement includes a capillary in parallel

communication with a section of the inlet passage. A charging flow phase control valve is provided. The phase control valve has an open position allowing flow of liquid refrigerant from the inlet through both the passage section and the capillary to the outlets. The phase control valve has a closed position shutting off flow through the passage section while permitting flow through the capillary. When the phase control valve is closed, flow through the capillary results in the refrigerant being vaporized.

In a process of recharging a system, the novel and improved manifold is connected to the system to be charged. The high side and state control valves are placed in open conditions. Refrigerant in liquid form is fed through the inlet opening thence through both the passage section and the capillary and then to and through the high side outlet to the system being charged to deliver refrigerant in liquid form. When it is desired to fill or to top-off with refrigerant in vaporized form, one simply closes the phase control valve and the high side outlet valve. The low side outlet valve is opened and further refrigerant flows from the inlet through the capillary where the refrigerant is vaporized and hence through the low side outlet into the system being charged. Concurrently the systems compressor is operated to top off the system high side while the input vapor tops off the low side.

When the system is used with refrigerants in older systems, top off is enhanced because the refrigerant is supplied in vapor form and the phase control valve is open.

Accordingly, the objects of the invention are to provide a novel and improved refrigerant manifold and a process of recharging systems utilizing refrigerant.

Brief Description of Drawings Figure 1 is an exploded view of one embodiment of a manifold device embodying the present invention; Figure 2 is an exploded view of a retrofit embodiment embodying the present invention; Figure 3 is a partially sectioned view of the embodiment of Figure 2;

Figure 4 is a perspective view on an enlarged scale of the capillary ring or annulus preferably used in all embodiments; Figure 5 is an elevational view of the capillary ring; Figures 6 through 9 are alternate embodiments of the annulus showing alternate capillary passages.

Figure 10 is a cross sectional view of the now preferred construction; Figures 11A-D are fragmentary cross sectional views of alternate arrangements for maintaining the capillary annulus in appropriate axial positions; and, Figure 12 is a sectional view of a check valve equipped embodiment for use in vacuum applications.

Best Mode for Carrying Out the Invention Referring to the drawings and to Figure 1 in particular, an embodiment which is now an alternate embodiment is shown. In this embodiment a manifold is shown generally at 10. The manifold includes a housing 12. High and low side pressure gauges 14,15 are carried by the housing. The gauges supply pressure readings of high and low sides of a connected heat transfer system.

The manifold 10 includes an inlet 16 for connection to a supply of refrigerant, typically a freon compound. The manifold also includes high and low side outlets 18,20 for delivering refrigerant to a connected system. High and low side outlet control valves 22,24 are connected to opposite ends of the elongate manifold 12 for selectively establishing and interrupting fluid communication from outlet passages within the manifold to the respective outlets 18,20.

A refrigerant state control assembly is shown generally at 25. A counter bore 26 is provided centrally of the manifold 12 in a manifold face 28 which is the forward face as viewed in Figure 1. A pair of drilled holes 30 are provided at the base of the counter bore 26. The drilled holes 30 are passages in direct communication with the inlet 16 for providing liquid refrigerant into a space defined by the counter bore and the state control

assembly 25.

The assembly 25 includes a mounting fitting 32 which is threadedably received in the counter bore 26 to secure the assembly 25 to the manifold.

An O ring is provided to effect a seal between the fitting 32 and the housing 12. While not visible in other of the drawings, such an O ring is shown at 33 and 33'in Figures 3 and 10. The manifold also includes a second and reduced size counter bore 34. The second counter bore 34 is axially aligned and in communication with the counter bore 26. A capillary ring or annulus 35 is positioned within the second counter bore 34 and seated against the base of the counterbore 34.

The assembly 25 includes a knob 36 connected to a valve stem 38.

Rotation of the knob 36 and the connected stem 38, shifts a valve member 40 into and out of engagement with a face surface 42 of the annulus 35.

Coaction of the valve member 40 and the face surface 42 selectively establishes and interrupts flow communication through an outlet passage 44 formed in the annulus 35. The outlet passage 44 is coaxial with the annulus 35.

In its presently preferred form, the annulus 35 has a perimetral helix 46 which is in close association with the walls defining the second counter bore 34. The walls of the counter bore 34 and the helix 46 coact to provide a helical passage 48 in the perimeter of the annulus 35. The helical passage 48 provides fluid communication between the inlet holes 30 and a central, state control outlet 50 provided at a base of the second counter bore 34. The state control outlet 50 communicates via internal passages in the manifold 12 with the high and low side outlets 18,20.

In Figures 6 through 8, alternate annuli 35', 35", 35"'are shown. In the embodiment of Figure 6, a sinusoidal helical groove 60 is provided. The groove extends from an inlet 62 around the perimeter of the annulus 35'to an outlet at 64. Figure 9 shows a further alternate capillary system in the form of a helically wound tube.

In the embodiment of Figure 7, a plurality of generally S-shaped grooves 66 are provided. Each of these grooves extends from an inlet

adjacent the face surface 42'across an outer surface 68 of the annulus 35"to an outlet at an axially opposite face of the annuls. The annuli 35'and 35", like the annulus 35, have perimetral grooves that coact with the cylindrical surface of the second counter bore 34 to define capillary paths.

In the embodiment of Figure 8, a plurality of capillary passages 70 extend through the annulus 35"'. The passages 70 each have an axis which parallels the axis of the annulus 35"'so that capillary flow is from the face 42"'to an opposite face through each of the passages 70.

Referring now to Figures 2 and 3, a retrofit unit is shown. The retrofit unit is designed for connection to an existing prior art charging manifold to convert it to a manifold which can be used for charging refrigerant into a system either in liquid or vapor state. The retrofit unit includes a housing or body 52. An inlet 54 is provided for a connection to a source of refrigerant. A refrigerant state control assembly 25, which is identical to the assembly of Figure 1, is provided. The assembly 25 includes the mounting fitting 32 which is connected to the body 52. The valve member 40 coacts with the annulus 35 in a manner identical to the coaction in the embodiment of Figure 1 except that a selected one of the props of Figures 10 and 11 is used but not shown. An outlet fitting 56 is connected to the body 52 and in fluid communication with the outlet of the refrigerant state control assembly. The outlet fitting 56 is adapted for connection to an inlet of a conventional and prior art manifold.

When the valve member 40 is seated against the face surface 42, the helical passage 48 functions as a capillary converting liquid refrigerant to its vapor state. An outlet from the capillary communicates with an expansion space 58, visible in Figures 3 and 10 a corresponding expansion chamber, not shown, is within the manifold body or housing 12 of Figure 1. The expansion space assures full vaporization of the refrigerant. Similarly, the pair of small inlet holes or passages 30 rather than a single hole of comparable cross-sectional area contribute to the efficient operation of the capillary action to assure full vaporization.

Referring now to Figure 10, a now preferred embodiment is shown. In

this embodiment like reference numerals to the numerals used in connection with the Figure 1 embodiment are used with primes added where there are differences. In this embodiment, refrigerant is introduced through the inlet 16 and is directed through two passages 30', only one of which is shown in Figure 10, to a space 72 above the capillary annulus 35'.

The annulus 35'is positioned in a bore 34'as distinguished from the counter bore 34 of Figure 1. This modification eliminates a shoulder against which the annulus of Figure 1 rests and thus omits a source of turbulence in fluid flow as refrigerant gasses exit the capillary. In order to maintain position of the annulus 35', a pair of props 74 are provided. These props are interposed between bores 76 in the annulus and the base of the bore 34'and thus extend through an expansion space which is below the annulus 35'and in communication with an outlet 77. The outlet extends in both directions from the expansion space to communicate with the outlets 18,20.

Figures 1 1 a-d show alternate arrangements for the props 74 to maintain the capillary in position against closing forces of the valve member 40'. Specifically in Figure 11 a and 11 b a cap extension 78 of the capillary 35"overlies the base of the space 44. In the embodiment of Figure 11, a tube 80 replaces the prop 74. The tube is in communication with the annulus central passage 44'and has a cross bore or ground away side portions to provide outlet ports 82. In Figure 11 d a snap ring 84 provides a seat for the annulus 35"'.

In Figure 12 a further alternate embodiment is shown. Here a capillary annulus carries a check valve 88. When liquid is being charged the flow is from the inlet 16'to a high side outlet, not shown. The low side outlet 20'will be closed at that time. When it is desired to provide refrigerant vapor to the low side, the high side outlet is closed, the low side outlet 20 prime is opened and a flow occurs around the capillary 86 but not through its axial passage because of the presence of the check valve 88. When it is desired to draw a vacuum on the system the check valve 88 will open allowing the low side to be evacuated as well as the high side.

Operation In operation with current refrigerants the device of Figure 1, the inlet fitting 16 is connected to a source of refrigerant in its liquid state. The high and low side outlets 18,20 are respectively connected to a system being charged typically following evacuation of that system. The high side valve 22 is opened as is the valve of the refrigerant state control assembly 25. The low side valve 24 is closed.

Liquid refrigerant is fed from the inlet 16 through a filter 90, Figure 10, to the supply holes 30. While not shown in the drawings all inlets and outlets of all embodiments are preferably similarly equipped with filters. The refrigerant then flows primarily through the axial passage 44 and also through the capillary helical passage 48 to the expansion chamber 58,58'and thence through the outlet 50 or 77. Refrigerant flows from the outlet 50 or 77 through internal passages in the manifold to the high side outlet 18. Flow is continued until a predetermined quantity of refrigerant has been supplied to the high side of a system being charged.

Once the predetermined quantity of refrigerant has been charged into the system high side, the knob 36 is rotated to bring the valve member 40,40' into flow interrupting contact with the annulus face 42,42'. The high side valve 22 is closed and the low side valve 24 is opened. The compressor of the system being charged is energized to cause the compressor to operate.

Thereafter, flow continues but only through the helical passage 48 which functions as a capillary to change the refrigerant being charged from its liquid to its gaseous state. Vapor charging continues until the system is fully charged.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction, operation and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.