Patent Application
20050221244
This invention pertains to gas-fired heating appliances, and more particularly to connecting an electrical cut-off (ECO) switch of such gas-fired appliances in a series electrical circuit relationship between an electrical terminal of a thermocouple and an electrical terminal of an automatic pilot valve magnet of a gas control valve of such a gas-fired heating appliance.
It has long been the practice in gas-fired heating appliances having a pilot light, such as water heaters, furnaces and clothes driers, (hereinafter collectively referenced as, gas appliances) to utilize a gas control valve that includes a magnetically operated safety valve for shutting off the flow of gas if the pilot light should be extinguished. Such magnetically operated safety valves typically include a device known in the industry as an automatic pilot valve magnet that is connected to a thermocouple exposed to the pilot light flame.
The pilot valve magnet is an electrically operated solenoid valve, having a valve poppet mounted on a movable armature, and an electrical coil that generates a magnetic flux for moving the armature when an electrical current is applied to the electrical coil. The electrical coil is connected to the thermocouple in such a manner that, when the pilot light is heating the thermocouple, and causing it to produce a flow of current through the electrical coil, the valve poppet is held in an open position allowing a flow of gas through the control valve. The pilot valve magnet also includes a spring for biasing the armature and poppet toward a closed position of the valve, so that if the pilot light is extinguished, thereby causing the thermocouple to stop providing and electrical current to the electrical coil of the pilot valve magnet, the spring will move the armature and poppet to the closed position of the valve, to thereby cut off the flow of gas through the gas control valve. A mechanism is also typically provided in the gas valve for mechanically opening and holding the poppet in an open position while the pilot light is being lit, and for a minute or so after lighting, while the pilot light flame is heating the thermocouple to a high enough temperature that the current it is producing will hold the valve poppet open.
It has also been the practice in some gas appliances to provide an electrical cut-off (ECO) switch, connected in a series electrical circuit relationship between the thermocouple and the automatic pilot valve magnet, for interrupting the flow of current from the thermocouple to the pilot valve magnet when the ECO switch is open, regardless of whether the pilot valve is burning or not. Such ECO switches are often actuated by bi-metallic elements that open the ECO switch in the event that an over-temperature condition occurs in the gas appliance. In a water heater, for example an ECO switch is often used for cutting off flow of gas through the gas control valve, if the temperature of water in the water heater rises above a predetermined maximum temperature.
The pilot valve magnet 116 includes an externally threaded portion 122 thereof for engaging mating threads 124 in the bore 112 of the valve housing 114. The interior end (not shown) of the bore 112 includes a valve seat (not shown) that is closed when a poppet 126 attached to the armature 128 of the pilot valve magnet 116 is moved to an extended position by a biasing spring 130 of the pilot valve magnet 116.
An exposed end 131 of the pilot valve magnet 116 extends outward from the valve housing 114, when the control apparatus 110 is installed in the bore 112, and includes a threaded central bore 132 for receiving a threaded coupling 134 of a thermocouple 136. A transversely extending slot 138, opening axially outward from the exposed end 131 of the pilot valve magnet 116, extends diametrically across the exposed end 131 end of the pilot valve magnet 116, for receipt therein of the ECO connector 118. The ECO connector is installed into the transversely extending slot 138 prior to installation of the control apparatus 110 into the bore 112, and is clamped in place by the crimp-on retainer 120, which has a lip 140 that is crimped into an annular groove 142 in the exposed end 131 of the pilot valve magnet 116, as shown in
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Although the control apparatus 110 described above has been used with great success for many years, there are some areas in which improvement is desirable.
For example, having the pilot valve magnet 116 configured to include such features as the externally threaded portion 122, for retaining the control apparatus 110 in the bore 112 of the valve 114, the threaded central bore 132, for receiving the thermocouple 136, the extending slot 138, for receiving the ECO connector 118, and the annular groove 142, for receiving the crimped edge 140 of the crimp-on retainer 120, add considerable complexity and cost to the pilot valve magnet 116. The pilot valve magnet 116 configuration is also typically unique to a particular gas valve 114, thereby precluding the use of a standardized pilot valve magnet that could be used in several gas control valves of differing configuration, to thereby reduce cost by increasing production volumes and reducing inventory.
Having the ECO connector 118 mounted in the slot 138 of the exposed end 131 of the pilot valve magnet 116 also undesirably increases the distance that the exposed end 131 extends from the valve 114. An additional problem is also created by this arrangement, with regard to installation of the pilot valve magnet 116 and routing of wires 156, 158 extending from the first and second ECO switch contacts 150, 152, because, as the pilot valve magnet 116 is threaded into the bore 112 of the control valve 114, the wires 156, 158 rotate with the pilot valve magnet 116, and may not be oriented in an optimal direction for connection to the ECO switch when the pilot valve magnet is tightened to its final position.
What is needed is an improved control apparatus for a gas control valve that solves one or more of the problems described above.
The invention provides an improved gas control apparatus for a gas control valve, solving the problems described above, through the use of an improved connector apparatus for connecting an electrical cut-off (ECO) switch of a gas appliance in a series electrical circuit relationship between an electrical terminal of a thermocouple and an electrical terminal of an automatic pilot valve magnet mounted in a bore of a gas control valve of the gas appliance.
In one form of the invention, the connector apparatus includes a spacer adapted for installation into the bore between the pilot valve magnet and the thermocouple, a connector adapted for engaging the spacer, and a retainer having an external thread on an outer periphery thereof for threadably engaging the bore and clamping the spacer against the pilot valve magnet. The connector includes first and second axially spaced electrical contacts that are electrically insulated from one another, with the first electrical contact being adapted for contacting the electrical terminal of the pilot valve magnet, and the second electrical contact being adapted for contacting the electrical terminal of the thermocouple. The retainer includes an internally threaded, axially oriented, through-hole therein for threadably receiving and retaining the thermocouple therein, with the electrical terminal of the thermocouple in contact with the second electrical contact of the connector.
In another form of the invention, a control apparatus is provided, for installation into a bore of a gas control valve of a gas appliance having an electrical cut-off (ECO) switch and a thermocouple, where the bore of the gas control valve defines a central longitudinally extending axis thereof and the thermocouple includes an electrical terminal thereof. The control apparatus includes an automatic pilot valve magnet that includes a pilot valve magnet electrical terminal at an axial end thereof and is axially insertable into the bore, in combination with a connector apparatus according to the invention.
In yet another form of the invention, a gas control valve is provided for a gas appliance having an electrical cut-off (ECO) switch and a thermocouple, where the thermocouple includes an electrical terminal thereof. The gas control valve includes a control valve housing having a bore therein defining a central longitudinally extending axis of the bore, and an automatic pilot valve magnet that includes a pilot valve electrical terminal at one end thereof and is axially insertable into the bore, in combination with a connector apparatus according to the invention.
According to one aspect of the invention, the bore of the gas control valve defines a generally cylindrical wall thereof having a window extending radially therethrough for passage of the connector, and the connector is adapted for insertion in a radial direction, through the window and into the slot in the spacer, after the pilot valve magnet, spacer, and retainer of the connector apparatus have been installed in the bore of the gas control valve.
According to another aspect of the invention, the window in the bore of the gas control valve defines an edge thereof, and the spacer includes one or more anti-rotation tabs extending radially outward therefrom for engaging the edge of the window, to thereby preclude rotation of the spacer in the bore as the retainer is threaded into contact with the spacer.
Other aspects, objectives and advantages of the invention will become apparent from the following detailed description when taken in conjunction with the accompanying 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 included within the spirit and scope of the invention as defined by the appended claims.
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In general, the pilot valve magnet 24 of the present invention is functionally identical to the prior pilot valve magnet 116 described above, but does not include the externally threaded portion 122, for retaining the control apparatus 110 in the bore 112 of the valve 114, the threaded central bore 132, for receiving the thermocouple 136, the extending slot 138, for receiving the ECO connector 118, or the annular groove 142, for receiving the crimped edge 140 of the crimp-on retainer 120, of the prior pilot valve magnet 116. Elimination of these features allows the pilot valve magnet 24 of the present invention to be considerably shorter, and easier to install than the prior pilot valve magnet 116. The pilot valve magnet 24 of the present invention is also simpler and less costly to manufacture, than the prior pilot valve magnet 116, and is usable as a standardized part in a variety of different gas valve applications.
The connector apparatus 16 includes a spacer 36, an ECO connector 38, and a retainer 40.
The spacer 36 is adapted, in a manner described in more detail below, for installation into the bore 26 of the valve body 12, between the pilot valve magnet 24 and the thermocouple 20, and for receiving the connector 38.
The connector 38 is adapted for engaging the spacer 36, in a manner described in more detail below. As shown in
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The first and a second ECO switch contacts 42, 44 each have a wire 80 attached to a distal end 81 thereof, adjacent an end of the connector housing 41 opposite the locking tangs 66. Because the thermocouple 136 is capable of producing only a very small electrical current, it is important that the wires 80 be attached to the switch contacts 42, 44 in a manner that creates very low electrical resistance. In this regard, it is contemplated that the wires 80 will generally be attached to the switch contacts 42, 44 by a process such as welding, brazing, or crimping. The first and second ECO switch contacts 42, 48 each also include barbs 82 for engaging the connector housing 41 to help retain the first and second ECO switch contacts 42, 44 in the first and second recesses 72, 74 respectively.
The connector 36 also includes a connector cover 84 attached to the connector housing 41 over the distal ends 81 of the first and second ECO switch contacts 42, 44. The connector cover 84 provides electrical insulation of the distal ends of the first and second ECO switch contacts 42, 44, and helps to retain the switch contacts 42, 44 in the connector housing 41. The connector cover 84 may be attached to the connector housing in any appropriate manner, such as snapping on, adhesive bonding, retained with screws or rivets, ultrasonic welding, etc. In the exemplary embodiment shown herein, the connector cover 84 is a snap-on device having locking spring-action lugs, that allow the cover 84 to be snapped onto the connector housing 41, for engaging the connector housing 41 to thereby retain the cover 84 in place on the connector housing 41.
The exemplary embodiments described herein represent preferred embodiments of this invention, including the best mode known to the inventors for carrying out the invention. Variations of these 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.
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) is 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. 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.
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.
