Patent Application
20050204769
Orifice piston expansion devices are utilized for metering the flow of pressurized fluid, such as refrigerant medium, along two or more fluid flow paths within a refrigeration or cooling system, such as between the condenser and evaporator coils of a heat pump or other such devices that include a reversible refrigeration cycle. More particularly, existing restrictive members, such as various types of pistons are used, within flow control distributor housings, to perform the required metering and bypass functions, which are well known in the art. Such existing expansion devices and pistons are shown and described, in U.S. Pat. No. 4,896,696, to Bradley et al. and in even more detail in U.S. Pat. No. 5,894,741 to Durham et al., which is also assigned to the assignee of the present invention. Such prior art flow control distributor housings were designed to generally receive only one style of such restrictive members or pistons.
In addition to the above-noted references, the patent literature includes a large number of orifice expansion devices or the like and included in this art are: U.S. Pat. No. 5,265,438 to Knowles et al.; U.S. Pat. No. 5,893,273 to Casiraghi; U.S. Pat. No. 6,363,965 B1 to Carmack et al.; U.S. Pat. No. 6,367,283 B1 to Ederle; and U.S. Pat. No. 6,560,987 B2 to Kreger et al. While the noted Kreger et al. patent discloses a cartridge for a restrictor, this cartridge only provides a seat for a bullet nose type of restrictor and will not accommodate the remaining piston styles. In addition, and importantly so, the cartridge is subsequently brazed in place and, consequently, not replaceable. It is deemed that none of the prior art structures, set forth in the noted references, pertain to the orifice expansion device, the improved orifice expansion device and the restrictor insert, of the present invention.
The present invention pertains to orifice expansion devices used in, for example in refrigeration and cooling systems, for conveying bi-directionally movable pressurized fluid. Specifically, this invention pertains to a cylindrical restrictor insert that permits the interchangeable use of differing restrictive members within a common distributor housing.
Referring now to the several drawings, illustrated in
Flow control distributor housing 12, which is of a generally cylindrical shape and which may be configured to include an intermediate hexagonal flats section 24, for engagement with wrench or the like, also includes a forward distributor end 26 and a rearward coupling end 28. Forward distributor end 26 is structured to terminate in an angled nozzle face 30, while rearward end 28 is externally threaded for connection to adaptor 18. Nozzle face 30 is provided with at least a single port opening 32 for admitting refrigerant medium flow through device 10. Housing 12 further includes a central fluid passageway 36 extending along a central longitudinal axis 38, from a forward passageway end 40 to an open rear passageway end 42. Forward passageway 40 is coupled in fluid communication with each of port openings 32 via individual associated ducts 34.
For effecting a fluid tight seal with restrictor insert 14, an annular frusto-conical valve seat 46 merges into passageway 36, intermediate forward and rear ends 40 and 42, respectively. The small diameter end of valve seat 46 merges into passageway 36 while the large diameter end thereof merges into an annular shoulder 48 which also forms the inner end of a chamber 50 having a cylindrical outer surface 52. Rearward coupling end 28 includes an annular end face 54 having a step portion 56, the small diameter end of which normally intersects open rear passageway end 42.
Turning now to restrictor insert 14, which is of generally cylindrical shape, includes a central, longitudinal, through bore 60 comprised of a cylindrical front or first bore portion 62, of a predetermined first diameter bore, coupled to a cylindrical intermediate or second bore portion 64, of a predetermined second diameter bore, via a frusto-conical joinder bore portion 66, and a cylindrical rear or third bore portion 68, of a third predetermined diameter bore. Restrictor insert 14 also includes a cylindrical central portion 72, having a cylindrical outer peripheral surface 74, a leading or front portion 76 having multiple annular steps 78, 80, as well as a leading frusto-conical front end surface 84, separated from step 80 via a peripheral groove 82 which serves to locate a seal member 94 preferably comprised of a PTFE material or the like. Restrictor insert 14 additionally includes a trailing or rear portion 86 having an annular outer shoulder step or surface portion 88 that is joined to an annular end surface 92 via an intermediate conical portion 90. The trailing end of inner cylindrical surface 52 of chamber 50 forms the inner diameter portion of annular end surface 92.
Continuing now with restrictive member, restrictor, or piston 16, which is shown for illustrative purposes only, is generally cylindrical in shape and is provided with a central, longitudinal through bore 100. Typical piston 16 includes an annular front end portion 102 that includes a frusto-conical or curved front end surface 104, with a radius 105, the former, in turn, merging into a cylindrical rear portion 106 having an annular rear end portion or surface 108. A typical prior art restrictor or piston of this type, referred to in the industry as a “bullet-nose” piston, is shown and described in U.S. Pat. No. 4,896,696 to Bradley et al. If desired, the cylindrical peripheral outer surface 110 of rear portion 106 can also be provided with a plurality of axially aligned flutes or channels (not shown) in a manner well known in the art and shown and described in previously noted U.S. Pat. No. 5,894,741 to Durham et al.
Turning now to adaptor 18, it is conventionally provided with a forward flange end 118, over which is received the known internally threaded nut or other conventional fastening member 20, for a threaded connection with coupling end 28 of flow control distributor housing 12, and a rearward tubular end 120, which is generally configured (not shown) for a brazed, soldered, sweat or other connection with a further tube, conduit or other refrigerant medium supply line in a manner well known in the art. Mounted within adaptor 18, at a peripheral inner cylindrical surface 122 of flange end 118, is a screen or other in-line filter member 124 adapted for separating particulate contaminants from the refrigerant medium flow. As will be discussed in more detail later, screen annular end face 126 serves as an abutment surface for piston annular end portion 108, when piston 16 is in the
Adaptor flange end 118 includes a further inner peripheral cylindrical surface 128 of a diameter slightly greater than that of the maximum outside diameter of piston 16 so as to permit free axial sliding movement of piston rear end portion 106 toward and away from screen end face 126. In addition, flange end 118 also includes a cylindrical portion 130, adapted to mate with an interior surface 58 of housing end face 54, while a flange end annular end face 132 is adapted to abut housing annular end face 54, upon the assembly of adaptor 18 to housing 12, as best seen in
In terms of the assembly of orifice expansion device 10, as best seen in
In terms of the operation of device 10, restrictive insert 14, when installed as described, has only limited axial movement capabilities within housing cavity 50, but piston 16 is capable of cycling, within insert 14, depending upon the direction of flow of the refrigerant medium, so as to alternately perform the required metering and bypass functions which are well known in the art. Specifically, piston 16, which is shown in
When the refrigerant medium flows from left to right, piston 16 is displaced, within restrictor insert 14, to the right, until its end portion 108 abuts screen end face 126, as illustrated in
The utilization of a separate, distinct, restrictor insert 14 allows independent coil manufacturers and installers to use any of the known types of restrictors or pistons 16 in the same or a common flow control distributor housing 12. Thus, for example, the three-fluted or five-fluted pistons, set forth in U.S. Pat. No. 5,894,741 to Durham et al., as well as the “bullet-nose” pistons, set forth in U.S. Pat. No. 4,896,696 to Bradley et al., can be used interchangeably. While restrictor insert 16 is illustrated as having a predetermined, specific axial extent, this can be adjusted, e.g., decreased if needed, so as to function successfully in other flow control housings. Therefore, while in the past, flow control distributor housings 12 were specifically designed and manufactured to accommodate but one style of piston 16, the present invention promotes ready interchangeability thus not only increasing choices, decreasing required part proliferation, inventories and costs, but also permitting a convenient, cost-effective, way of replacing or substituting pistons 16, if so desired. In the prior art structures the entire orifice expansion device had to be replaced.
It is deemed that one of ordinary skill in the art will readily recognize that the present invention fills remaining needs in this art and will be able to affect various changes, substitutions of equivalents and various other aspects of the invention as described herein. Thus, it is intended that the protection granted hereon be limited only by the scope of the appended claims and their equivalents.
The present application claims the benefit of the filing date of U.S. Provisional Application Serial No. 60/554,096, filed Mar. 18, 2004, the disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60554096 | Mar 2004 | US |
