Patent Application
20060037652
This invention pertains generally to reversing valves and more particularly to reversing valves having a solenoid-operated pilot valve for controlling operation of the reversing valve.
Reversing valve assemblies are typically used in fluid flow systems in which a fluid is directed to flow in various alternative loops or circuits. For instance, heat pumps are specialized refrigeration systems that can be selectively configured to operate in either of two different modes. In the first mode, known as the cooling mode, energy in the form of heat is removed from an “inside” environment and transferred to an “outside” environment. In the second mode, known as the heating mode, heat energy is transferred into the inside environment. To convey the heat energy, the heat pump system utilizes a compressor to circulate fluid refrigerant through a closed-circuit system that includes heat transfer coils located in each environment. In addition to circulating the refrigerant, the compressor is used to impart thermodynamic energy into the system.
To change the heat pump system between heating and cooling modes, the system includes the reversing valve assembly which can be selectively manipulated to alter the flow of refrigerant. The reversing valve assembly typically includes a reversing valve body having multiple ports that are interconnected with the heat transfer coils and the compressor. The reversing valve body also encloses a movable valve member that can be selectively placed between two different positions wherein the valve member directs refrigerant flow between different groupings of the ports. The valve member is moved in response to a change in actuating pressure that is supplied to the reversing valve body. Fluid refrigerant drawn off from the system is typically used as the source for the actuating pressure.
To control the change in the actuating pressure and thereby control the motion of the valve member, the reversing valve assembly typically includes a pilot valve assembly that is attached to the reversing valve body. The pilot valve assembly is an electrically-operated device that is in fluid communication with both the reversing valve body and the heat pump system to draw off refrigerant. To change the actuating pressure supplied to the reversing valve body, the pilot valve assembly includes an elongated pilot valve body having a plunger reciprocally movable therein. Different positions of the plunger cause the pilot valve assembly to alter the supply of the actuating pressure to the reversing valve body. The position of the plunger can be altered by activating a solenoid coil that surrounds a portion of the pilot valve body.
To attach the pilot valve assembly to the reversing valve body, often a mounting bracket is rigidly joined to the reversing valve body. The pilot valve body can be received in and extend from the mounting bracket. To secure the pilot valve body to the mounting bracket, the pilot valve body is often crimped in place or retained to the mounting bracket with a retainer clip. Crimping the pilot valve body greatly complicates its later removal from the reversing valve assembly for repair and replacement. Furthermore, the solenoid coil is typically provided with a distinct solenoid coil frame that must be separately installed to the mounting frame with another fastener. This prior art attachment method requires the use of separate mounting brackets and coil frames. Additionally, the solenoid coil frame is often installed over the extended portion of the pilot valve body in a cantilevered fashion. Cantilevered mounting of the solenoid coil subjects the pilot valve assembly to possible damage due to impact during handling and installation of the reversing valve assembly.
U.S. Pat. No. 4,712,582, assigned to Ranco Incorporated, herein incorporated in its entirety by reference, addresses the drawbacks of separately mounting the pilot valve body and the solenoid coil frame. U.S. Pat. No. 4,712,582 describes mounting an anchoring panel to the reversing valve body, then inserting the pilot valve body through the anchoring panel such that a portion of the valve projects away from the anchoring panel. A solenoid is next inserted over a projecting portion of the pilot valve body and placed adjacent to the anchoring panel. A retainer panel is detachably connected to the projecting portion of the pilot valve body to enclose the solenoid between the anchoring panel and retainer panel.
While this attachment arrangement provides significant benefits, utilizing both an anchor panel and a detachable retainer panel necessarily requires the manufacture of two separate parts, resulting in an increase to the cost of the reversing valve assembly. Additionally, the use of multiple parts complicates assembly of the reversing valve assembly, further increasing the cost. Also, to detachably connect the retainer panel, a threaded nut is fastened over the projecting portion of the pilot valve body thereby clamping the solenoid coil between the anchoring panel and retainer panel. Care must be taken during assembly to avoid over-tightening the nut and damaging the solenoid coil.
The present invention provides a reversing valve assembly having an improved mounting structure for attaching a pilot valve assembly. The reversing valve assembly includes a mounting bracket having at least three sides, including an anchor panel attached to the reversing valve body, a first leg panel extending perpendicularly from the anchor panel, and a second leg panel likewise extending perpendicularly from the anchor panel and parallel to the first leg panel. Disposed through the first leg panel is a first aperture while preferably disposed through the second leg panel is a second aperture. The first and second apertures are aligned with each other about a common axis line.
In some forms of the invention, the first and second leg panels of the mounting bracket define respective distal ends thereof, which are joined by a top panel. The first leg panel may be bowed inward toward the second leg panel, for applying a compressive holding force on the solenoid coil. The first leg panel may also be severed through the first aperture to form an upper portion of the first panel extending from the top panel, and a lower portion of the first panel extending from the anchor panel.
To activate the pilot valve assembly, an electrically actuated solenoid coil is provided. The solenoid coil has a central bore and is inserted in the three-sided mounting bracket between the first and second leg panels such that the central bore is aligned with the first and second apertures about the axis line. The pilot valve assembly includes an elongated pilot valve body that extends between a first end and an opposing second end. The pilot valve body is sized to engage in a sliding fit with the central bore. Disposed at various orientations into the pilot valve body proximate to the first end are a plurality of ports that are used to communicate with the reversing valve body and the refrigerant system.
To assemble the pilot valve assembly with the solenoid and the mounting bracket, the pilot valve body is inserted through the first aperture and received into the central bore, thereby aligning the pilot valve body with the axis line. When completely inserted, the second end of the pilot valve body abuts against the second leg panel while the first end extends from the first leg panel so that the ports are unobstructed. To hold the assembled pilot valve assembly, solenoid coil and mounting bracket together, the second end is secured to the second leg panel by way of, for example, a threaded fastener inserted through the second aperture. Securing the second end to the second leg panel also secures the solenoid coil to the mounting bracket. Advantageously, this manner of securing the components together does not compress the solenoid coil between the two parallel leg panels.
An advantage of the present invention is that the mounting bracket concurrently mounts both the pilot valve assembly and the solenoid coil to the reversing valve. Another advantage is that the mounting bracket, including the three panels, can be manufactured as a single piece. Another advantage is that the same act of securing the pilot valve body to the mounting bracket simultaneously secures the solenoid coil to the mounting bracket. These and other advantages and features of the present invention will be apparent from the detailed description and the accompanying drawings.
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:
While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
Now referring to the drawings, wherein like reference numbers refer to like elements, there is illustrated in
The reversing valve assembly 100 includes a reversing valve 102 for selectively directing refrigerant through the heat pump system. The reversing valve 102 includes a tubular, elongated reversing valve body 110 from which extends at least four flow tubes 112, 114, 116, 118. The flow tubes can interconnect with refrigerant flow lines to establish fluid communication between the reversing valve 102 and the other components of the heat pump system. Typically, the first flow tube 112 communicates with the high pressure discharge of the compressor while the second flow tube 114 communicates with the low pressure inlet of the compressor. The third and fourth flow tubes communicate with the heat exchangers. To direct refrigerant flow between various flow tubes, there is enclosed in the reversing valve body 110 a reciprocally moving valve member (not shown). The position of the movable valve member within the reversing valve body 110 governs the direction of refrigerant flow through the heat pump system and thus determines whether the system is operating in the heating or cooling mode.
To control the position of the valve member, the reversing valve assembly 100 also includes a pilot valve assembly 104 mounted to the reversing valve 102. The pilot valve assembly 104 utilizes the pressurized refrigerant flowing in the heat pump system and converts that refrigerant pressure to an actuating pressure that physically moves the valve member. To accomplish this, in the illustrated embodiment, the pilot valve assembly 104 communicates by pipette 130 (see
Referring to
To mount the pilot valve and solenoid coil to the reversing valve, a mounting bracket 170 is provided. The mounting bracket preferably has at least three sides, and is preferably manufactured from a ferrous metal or other similar magnetically permeable material. The intermediate side of the mounting bracket is defined by an anchor panel 172. Extending generally perpendicularly from an edge of the anchor panel 172 is a first leg panel 174 while extending generally perpendicularly from an opposite edge of the anchor panel is a second leg panel 176. Accordingly, the two leg panels 174, 176 are generally parallel to each other and are spaced apart from one another by the anchor panel 172.
Disposed through the first leg panel 174 is a first aperture 180 while preferably, but not necessarily, disposed through the second leg panel 176 is a second aperture 182. The first and second apertures 180, 182 are positioned within the leg panels so as to be aligned with one another and thereby define an axis line 106. Accordingly, the anchor panel 172 is offset below the axis line 106 while the first and second leg panels 174, 176 are generally perpendicular to the axis line. In the illustrated embodiment, the apertures 180, 182 are circular in shape, with the diameter of the second aperture being smaller than the diameter of the first aperture. Preferably, the diameter of the first aperture 180 is dimensioned to produce a sliding fit with the pilot valve body 140.
The mounting bracket 170 is formed as a single integral piece with the first and second leg panels 174, 176 permanently joined to the anchor panel 172. Each of the panels can have a generally rectangular, planar shape. Preferably, the mounting bracket including each of the panels and the apertures is formed from a common blank of material through a stamping and bending operation. Producing the mounting bracket as a single piece results in substantial savings in the cost of material and manufacturing.
Referring again to
As illustrated in
In an embodiment, to exert a compressive holding force upon the solenoid coil 160, the first and second leg panels 174, 176 converge slightly towards each other as they extend from the anchor panel 172. The slightly converging leg panels 174, 176, while still being generally parallel, act as a spring biasing against the respective first and second coil faces 162, 166. To avoid damaging the solenoid coil, the compressive force exerted should be the minimum necessary to hold the solenoid coil in place during assembly. Another advantage of converging the leg panels to exert a compressive force is that rattling of the solenoid coil between the leg panels during operation of the reversing valve is reduced or eliminated. A further advantage of converging the leg panels to exert a compressive force is a further improvement in magnetic coupling between the solenoid coil and the mounting bracket.
To add the pilot valve assembly 104 to the mounting bracket 170 and the solenoid coil 160, a portion of the pilot valve body 140 is inserted through the first aperture 180 and into the central bore 166. Because of the sliding fit between the pilot valve body 140, the first aperture 180, and the central bore 166, the cylindrical pilot valve body is aligned with the axis line 106. When completely inserted, the second end 146 of the pilot valve body 140 abuts against the second leg panel 176 adjacent the smaller second aperture 182. Additionally, the first end 144 of the pilot valve body 140 extends from the first leg panel 174 through the first aperture 180 so that the ports 150 are accessible.
To hold the pilot valve assembly 104 to the mounting bracket 170, the second end 146 is secured to the second leg panel 176 through the second aperture 182. As will be appreciated, because the pilot valve body 140 passes through the central bore 166, the act of securing the second end 146 to the second leg panel 176 likewise secures the solenoid coil 160 to the mounting bracket 170. Advantageously, the act of securing the second end 146 directly to the second leg panel 176 does not place the solenoid coil under compression between the first and second leg panels, thereby avoiding potential damage of the solenoid coil from over-compression. The pilot valve body can be secured to the second leg panel by any of a number of securing methods.
For example, referring to
In other embodiments, the second end 146 can be secured to the second leg panel 176 in various other manners. For example, referring to
Referring to
Referring to
Referring to
In the embodiment in which the second leg panel does not include the second aperture, the second end of the valve body can be secured directly to the second leg panel by, for example, adhesive bonding.
The four-sided mounting bracket 242 in the exemplary embodiment shown in
The first leg panel 246 includes a first aperture 256, corresponding to the first aperture 180 of the embodiment shown in
As best seen in
Hence, the present invention provides a novel mounting structure for mounting a pilot valve assembly and a solenoid coil to a flow reversing valve. The mounting structure includes a mounting bracket having at least three sides that can be manufactured as a single piece. Disposed through first and second generally parallel leg panels that correspond to two opposing sides of the mounting bracket are aligned first and second apertures. A solenoid coil for activating the pilot valve assembly is placed between the opposing leg panels such that the central bore of the solenoid coil aligns with the apertures about a common axis line. The pilot valve assembly includes an elongated valve body that is sized to be slidably received in the central bore. When assembled together, an end of the pilot valve body abuts against one of the opposing leg panels while a portion of the pilot valve body extends through the respective aperture of the other leg panel. To hold the pilot valve, solenoid coil, and mounting bracket together, the end of the pilot valve abutting the leg panel of the mounting bracket is secured thereto.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
