Valve assembly

Abstract: A valve assembly (10,110,310) for controlling the flow of flammable gas to a burner, comprising a body (14,114,314) having a passageway (16,116,316) for flow of gas from an inlet (12,112,312) and a valve (37,137,337) having a valve seat (36,136,336) and a closure (40,140,340) which valve is positioned between first and second outlet channels (24,26,124,126,324,326) from the passageway wherein the first and second channels are axially separated along the passageway (16,116,316) such that axial movement of the closure (40,140,340) along the passageway (16,116,316) effects opening and closing of the valves.

Description: The invention relates to a valve assembly for controlling the flow of inflammable gas to a burner such as in a domestic fire. It is known to provide valve assemblies which allow gas to flow to a burner at different rates thereby to control the level of heat output from the burner. However, such devices generally comprise simple manually operated rotary controls or electronically activated valve actuators which open and close valves to control gas flow. A known actuator can for example comprise a solenoid and accordingly such systems can be expensive to manufacture especially if a number of different levels of gas flow are required. Another known valve assembly is disclosed in DE 910 585 C. The invention seeks to avoid or at least mitigate problems of the prior art. An object of the invention is to provide a valve assembly which is operable using a linearly or axially moveable control. Another object of the invention is to provide a valve assembly which is easy to operate and indeed can be manually operated without the need for rotary motion or electronic controls. Another object of the invention is to provide a valve assembly which can provide several different levels of gas flow to a burner. According to a first aspect of the invention there is provided a valve assembly for controlling the flow of flammable gas to a burner, comprising a body having a passageway for flow of gas from an inlet and a valve having a valve seat and a closure which valve is positioned between first and second outlet channels from the passageway wherein the first and second channels are axially separated along the passageway such that axial movement of the closure along the passageway effects opening and closing of the valves. Beneficially therefore by sliding the valve closure along the passageway away from the valve seat it is possible to allow gas to flow through both the first and second outlet channels to a burner thereby increasing the heat output from the burner. Beneficially, axial movement of the valve can be effected manually using a spindle attached to the valve closure. Preferably the valve comprises a valve closure resiliently biased towards a valve seat and means is provided for effecting movement of the closure against the action of the resilient biasing means. The movement means can comprise a spindle on which the valve closure is slidably mounted. Further, the spindle can carry a lug in a fixed axial position for effecting movement of the valve closure. In a preferred form, the gas passageway comprises a series of two or more axially aligned sections which sections increase in cross sectional area relative to an upstream neighbouring section. Beneficially therefore a series of closures of increasing diameter can be used to prevent gas flow between adjacent sections. Preferably a metering device is provided to enable a user to determine how many valves in the valve assembly are open and therefore how great the gas flow through to a burner is. In a preferred form, the metering device comprises a spindle having one or more recesses which cooperate with a resiliently biased member operably received in the recess. A series of notches can be provided. The metering device which enables a user to accurately select rates of flow through the outlet from the valve assembly can in one form of the invention be provided by a second movable spindle co-operating with a locking device. The second spindle can comprise a series of recesses and co-operate with a resiliently biased device comprising for example a spring and ball bearing arrangement. Preferably, a micro-switch is located on the valve assembly for deactivating a safety valve when the user locates the means for effecting movement of the valve closure or closures at a predetermined position. In one form, the micro-switch co-operates with the second spindle whereby the micro-switch is actuated when the second spindle is placed in a predetermined position such as withdrawn beyond the micro-switch contact. If desired, a second micro-switch could be arranged to be operated in the same way, e.g. located at right angles to the first, and to energise additional circuits. In a further form, means is provided for stabilising the movement of a spindle used to effect movement of the valve closure or closures within the valve assembly. The stabilising means can comprise a second spindle connected by an arm to the closure moving spindle and can therefore provide relative rigidity to the system. Another aspect of the invention provides a valve assembly comprising a body having a gas inlet to a passageway comprising a valve for controlling gas flow from the body, wherein the valve is disposed intermediate two outlet channels which channels are substantially axially parallel to one another and lead to a larger diameter outlet in the body. Beneficially therefore, a large diameter outlet bore can be machined into the valve assembly body and two smaller diameter bores or channels drilled substantially parallel to one another the axis of the larger diameter bore. Therefore parallel machining axes are used reducing the time and cost of machining the valve assembly body. A further aspect of the invention provides a valve for controlling the flow of fluid from an inlet to a series of outlets whereby flow may take place at any of a plurality of different rates, according to the setting of a control member, wherein said outlets are connected by individual branch passages to a common flow passage communicating with said inlet, said control member extends along said common flow passage, and a series of separate flow control valves is disposed in said common flow passage and is arranged for sequential opening or sequential closing when said control member is axially displaced in one or other direction. Also, the invention provides a valve for controlling the flow of fluid comprising a main flow passage having successive axially adjacent portions of increased cross sectional area and connected to an inlet for fluid supply, a control member extending along said passage, a series of valve members each associated with a different one of said portions and enclosed positions arranged to prevent flow from one of said portions to the next adjacent thereof, and means provided on said control member so that in continued axial movement thereof in one direction said valve members are successively moved to and held in open positions, where flow to said next portion(s) is possible, and in continued axial movement thereof in the opposition direction said valve members are successively restored to their closed positions. Also, the invention provides a gas valve comprising a common flow passage having at least two axially successive portions of different diameters, a valve seat formed at the junction of two of said portions, a valve associated with said seat for preventing flow between said two portions, a valve stem for displacing said valve to allow flow, an outlet associated with said valve seat and connected to said common flow passage by a pair of branch passages each extending between a different one of said two portions and the said outlet, whereby flow may occur through said outlet at two different rates according to whether said valve is displaced or not. According to a further definition the invention provides a gas valve comprising a stepped main flow passage having a series of axial portions of successively greater cross sectional area, a separate valve closure element associated with each of at least some of the said portions and arranged when closed to prevent flow from one to the next of said portions, a valve stem extending along said passage, a series of couplings on said stem, each said coupling associable with a different one of said valve closure elements, and the spacing of said valve closure elements and couplings being such that axial movement of said stem displaces the valve closure elements from closed to open position or vice versa according to the direction of movement and in sequence along the passage, and a series of branch passages opening from said main passage connectable to the respective outlets whereby gas flow rate from the outlet(s) depends upon the open or closed status of the respective valves. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a sectional side elevation view of a first embodiment of a valve assembly according to the invention; Figure 2 is an enlarged view of part of the assembly shown in Figure 1,; Figure 3 is a sectional side elevation view of a second embodiment of a valve assembly according to the invention; Figure 4 is a side elevation view of a spindle for a slider control according to the invention; Figure 5 is a sectional side elevation view of a spindle housing for a slider control according to the invention; and Figure 6 is a sectional side elevation view of a third embodiment and valve assembly according to the invention. Referring to Figure 1 there is shown a valve assembly 10 according to the invention comprising an inlet 12 in a body 14 comprising passageway 16 which connects inlet 12 to outlets 18 and 20. Assembly 10 further comprises a safety valve 22 such as a thermoelectric valve which can be maintained open using a thermocouple operably placed in a flame (for example from a pilot light) provided from gas from outlet 18. Outlet channels 24 and 26 are also provided which connect passageway 16 to outlet 20 via a connecting bore 28. Each of channels 24 and 26 comprise flow regulators such a threaded screw valve which varies the cross sectional area at the interface between the respective channel 24 or 26 and bore 28. As can be seen in Figure 1, passageway 16 between inlet 12 and outlet 20 comprises a series of sections. Of significance to the operation of assembly 10, is a first section 30 downstream from safety valve 22, a second section 32 of greater diameter than section 30, and a third section 34 of greater diameter than second section 32. A valve seat 36 for a first valve 37 is provided intermediate sections 30 and 32, and a second valve seat 38 for a second valve 39 is provided intermediate sections 32 and 34. Additionally, a passageway end closure 40 is provided for preventing leakage of gas adjacent control 42 comprising a spindle 44. Closure 40 can for example comprise an O-ring for sealing against spindle 44. Spindle 44, which in this example comprises two sections which are axially aligned, carries a first valve closure 46 for first valve 37, and a second valve closure 48 for second valve 39. Referring to Figure 2, valves 37 and 39 are shown in greater detail. As can be seen, valve 37 comprises a closure 46 having a sealing element 50 which abuts first valve seat 36 to prevent gas flow along passageway 16 (that is between sections 30 and 32). Closure 46 is slidably mounted on spindle 44 and carries an O-ring 52 for sealing against the spindle. In this embodiment an end plate 54 is provided for abutting against a coiled spring 56 also mounted on spindle 44 which abuts lugs 58 remote from closure 46. Lugs 58 could alternatively be a flange on spindle 44 or a circlip for example. Further lugs 60 similar to lugs 58, are provided upstream from valve closure 46 which further comprises an abutting surface 62 which is engaged or contacted by lugs 60 in use to displace the closure. Similarly, closure 48 of valve 39 comprises a sealing member 62 such as a resilient washer for example made of rubber, which seals against seat 38. Closure 48 is also slidable mounted on spindle 44 and carries an O-ring 64 for sealing against spindle 44 thereby to prevent gas flow along the spindle. Again, an end plate 66 is provided for abutting against a spring 68 which is carried on spindle 44. In this case, spring 68 abuts a shoulder of spindle 44 between a smaller diameter section of spindle 44 and a larger diameter section. As can be seen, a recess is provided in closure 48 for receiving the larger diameter section of spindle 44. Additionally, an abutting surface 72 is provided on the upstream end of closure 48, which surface 72 is abutted by lugs 58 in use. Also, spindle 44 carries a lug such as a circlip 70 for preventing withdrawal of the spindle too far beyond end closure 40. An outlet 33 is provided for testing gas pressure in section 32 in this embodiment. Normally this outlet is sealed. The operation of assembly 10 will now be described with reference to Figures 1 and 2. Spindle 44 is initially moved inwardly to open valve 22 thereby to allow gas flow from inlet 12 to outlet 18 (as well as channel 24). A switch (not shown) carried on spindle 44 can be used to actuate an electronic igniter to light the gas as a pilot light in a burner, such as in a gas fire, connected to outlet 18. A thermocouple or other suitable device such as an ionisation device, placed in or near the pilot light flame keeps valve 22 open even when spindle 44 is pulled outwardly from assembly 10. The position shown in Figure 1 is that when spindle 44 has been pressed into body 14 thereby to open valve 22 and effect ignition of a pilot light. After ignition, spindle 44 can be withdrawn by sliding spindle 44 axially along passageway 16 and end closure 40. As well as allowing gas to flow to a pilot light in this initial state, gas is also able to flow through first outlet channel 24 through to outlet 20 governed only by the diameter of the channels, or a flow regulator within channel 24. Thus, in a first low level rate of flow gas to a burner is provided which gas will be ignited by the pilot light. Valves 37 and 39 are sealed due to the action of springs 56 and 68 respectively on closures 46 and 48 respectively and the relative position of spindle in the body. This action effect a seal at both seats 36 and 38. By drawing spindle 44 out of body 14, lugs 60 abut surface 62 and by continuing to pull on spindle 44, eventually lugs 60 pull closure 46 away from seat 36 thereby to allow gas to flow between section 30 and 32 and out through outlet 20 via channel 26. Therefore, a second higher rate of gas flow is provided through to a burner. Since the separation of lugs 58 and 60 is less than the separation of nut 70 and lugs 58, closure 46 is moved away from seat 36 before lug 58 contacts surface 72 of closure 48. Therefore, spring 68 effects closure of second valve 39 after valve 37 has been opened. An additional factor in the required displacement of spindle 44 in the sequence of opening of valves 37 and 39 is the thickness of the valve closure 46 between surfaces 54 and 62, and closure 48 between surfaces 66 and 72. As is apparent, by withdrawing spindle 44 further from body 14, it is possible to engage surface 72 with lugs 58 thereby to pull closure 48 away from seat 38 allowing flow of gas to sections 32 and 34 and into outlet 20. Similarly, by moving spindle 44 back into body 14, closure 48 will first contact seat 38 thereby reducing the amount of flow to the burner and eventually closure 46 will abut seat 36 thereby to reduce the flow to a minimum level. An off switch can be provided which for example cuts the flow of the current between the thermocouple and safety valve 22 thereby to close valve 22 and prevent flow of gas to either of outlet 18 or 20. A second valve assembly 110 according to the invention is shown in Figure 3. In this embodiment features in common with the embodiments shown in Figures 1 and 2 are given the same two digit reference numeral prefixed with the number 1. Accordingly, a valve assembly 110 comprises an inlet 112 into a body 114 comprising a passageway 116 allowing gas flow through to outlets 118, 120 and 176. Assembly 110 further comprises a safety valve 122, a first valve 137, and a second valve 139. However, because a third outlet 176 is provided, a third valve closure 178 is also used to control gas flow to a burner. Additionally, passageway 116 comprises four sections of different diameters namely sections 130, 132, 134, and 174. Valves 137 and 139 operate in the same manner as valves 37 and 39 of the first embodiment except that spring 168 is disposed between closure 148 and a third closure 178 comprising a sealing member such as an O-ring 180 which effectively abuts the inner surface of channel 134 to prevent gas flow through to outlet 176. Additionally, in this embodiment first and second outlet channels 124 and 126 are substantially parallel and, while still axially separated, connect to an outlet 120 having a substantially parallel axis. Accordingly, outlet channels 124 and 126 can be relatively easily drilled into body 114. In use, having depressed spindle 144 fully into body 114 thereby to open the valve 122 and ignite a pilot light which receives gas via outlet 118, it is possible to withdraw spindle 144 to effect three levels of gas flow through to a burner. Using this assembly 110, only a pilot light is initially provided. However, by opening valve 137, gas is allowed to flow through to outlet channel 124. By withdrawing spindle 144 further, it is possible also to open valve 139 thereby to allow gas to flow through outlet channel 126. Moreover, by further withdrawing spindle 144 eventually closure 178 is drawn from section 134 into section 174, of larger diameter, thereby allowing gas flow through outlet 176. In this embodiment, closure 178 is positioned along spindle 144 at a point which allows a seal on the inner surface of passageway section 134 when lugs 158 lift closure 148 of valve seat 138. Again, it is the relative axial separation of the features which determines the amount of displacement of spindle 144 to effect opening of the valves in turn. Referring to Figures 4 and 5, there is shown a metering device enabling a user to select the position of a spindle 244 in a valve assembly. Spindles 44 and 144 of the embodiments shown, require that friction is provided in order to prevent the action of springs 56, 68, 156, or 168 causing spindle 144 to be pushed outwardly to an undesired position. In the first embodiment, this friction is provided by the O-ring in end closure 40, and in the second embodiment it is provided by the O-ring 180 as well as the O-ring in end closure 140. A spindle restraining force can also be provided externally of body 14 for example using a hand-tightened gland comprising a threaded nut for compressing an O-ring, or simply using the weight of a vertical rod attached to a vertically positioned spindle 44. Such a restraining device can also comprise a metering device for regulating flow of gas. The metering device shown in Figures 4 and 5 comprises an end closure 240 comprising means such as threading 282 for attaching the closure to the valve assembly body. A recess 284 is provided for an O-ring seal to prevent gas leakage through the end closure 240 via bore 286 which receives a spindle 244. Additionally, a bore 288 is provided, in this example orthogonal to bore 286. Bore 288 can carry a resilient elongate member which protrudes into bore 286 or other means such as a bearing which protrudes into bore 286. Spindle 244 comprises a means 290 such as a threaded bore for connecting to a second section thereby to provide an overall desired length of spindle able to actuate safety valve 22 etc. Spindle 244 further comprises a first annular recess 292 and axially spaced therefrom, a second annular recess 294 and third recess 296. In use, spindle 244 can be depressed when inserted into the body of a valve assembly thereby to effect ignition of a pilot light and thereafter released allowing recess 294 to be engaged by an abutting or resilient member in bore 288 which restricts further axial movement of spindle 244. This position could indicate to the user that only the pilot light is on in the second embodiment or the pilot light plus the low rate flow is on in the first embodiment. By withdrawing spindle 244 so that recess 292 is engaged by the abutting means in bore 288, a second level of gas flow through to a burner can be provided and finally, third recess 296 can be used to indicate a third level of gas flow through to a burner. An appropriate number of recesses or notches can be provided in accordance with the number of levels of gas throughput from a valve assembly to a burner. It will be appreciated that the spindle 144 can be manually operated to provide easy control of gas through to a gas fire for example. Alternatively, an actuator such as a servo-motor could be used to effect the axial movement of spindle 144 to control gas flow. A further embodiment of a valve assembly according to the invention is shown in Figure 6. Valve assembly 310 is substantially similar to valve assembly 10 shown in Figures 1 and 2 and accordingly like features are given the same two digit reference number prefixed with the numeral 3. In this embodiment however, the means of monitoring or metering gas flow through the outlet 320, that is indicating to the user the setting of the valve assembly, is positioned remote from spindle 344. In this embodiment spindle 344 carries an extension 345 for operation by a user. Spindle 344 further carries a connecting arm 347, such as a stiff rod, connecting it to a second spindle 349 which is received in a bore 329 within the valve body. As can be seen, bore 329 is a larger diameter region of bore 328 isolated therefrom by a plug 331. Bore 329 is substantially parallel to passageway 16. Accordingly, the connection of spindle 344 to spindle 349 provides greater rigidity to the assembly and assists in guiding spindle 344 axially along passageway 16. Additionally however, user spindle 349 enables the location of a micro-switch M and a biased locking device 397 remote from spindle 344. Accordingly, a bore 388 is provided for receiving a locking device 397 such as a ball bearing received within the bore or recess 388 and biased towards 399 by a spring arrangement. Similarly micro-switch M can be attached to the valve assembly body and located adjacent spindle 349 so that a resiliently biased member or contact arm abuts spindle 349. In use therefore, by moving spindle 344 in to the valve assembly body, safety valve 322 is opened allowing gas to flow between inlet 312 and first outlet 318. At the same time, a micro-switch not shown can be actuated in order to ignite the gas at a pilot light. As described above, when the pilot light 318 is lit, safety valve 322 is retained open and accordingly a user is able to adjust the rate of flow to the burner via outlet 320 by withdrawing spindle 344. When locking device 397 is located in recess 392, this indicates to the user that the burner is on a first rate setting whereby gas flows through first regulator 324 to the outlet 320. By withdrawing spindle 344 further, this causes spindle 349 to be withdrawn from valve 329. When locking device 392 locates in recess 394, this indicates to the user that a second flow rate has been achieved whereby gas flows through second regular 326 to outlet 320. Further removal of spindle 344 causes the spindle 349 to be withdrawn until the resistance to withdraw is met when locking device 397 locates in recess 396. This indicates to the user that the highest rate of burner is achieved in this assembly whereby gas flows through outlet 320 via passageway 316. Further removal of spindle 344 causes a contact arm of micro-switch M which rests against spindle 349 to move thereby opening the micro-switch circuit and closing safety valve 322. That is, the end of spindle 349 passes beyond the bottom micro-switch M in order to allow the resilient arm feed move outwardly into bore 329. However, a large recess could be provided in spindle 349 for this purpose also.

Claims: A valve assembly for controlling the flow of flammable gas to a burner, comprising a body (14) having a passageway (16) for flow of gas from an inlet (12) and a valve (37) having a valve seat and a closure which valve is positioned between first (18) and second (20) outlet channels from the passageway wherein the first and second channels are axially separated along the passageway such that axial movement of the closure along the passageway effects opening and closing of the valve; wherein the passageway comprises a series of two or more coaxial sections (30, 32, 34) which sections increase in cross sectional area relative to an upstream adjacent section; a series of closures (46,48) of increasing diameter operable to prevent gas flow between adjacent sections, and a spindle (44) on which the valve closures are slidably mounted. A valve assembly according to Claim 1 wherein axial movement of the valve closures can be effected manually using the spindle. A valve assembly according to Claim 1 or 2 wherein the valve comprises a valve closure resiliently biased towards a valve seat. A valve assembly according to any preceding claim wherein the spindle carries a lug in a fixed axial position for effecting movement of the valve closure. A valve assembly according to any preceding Claim comprising a metering device enabling a user to determine how many closures in the valve assembly are open and therefore level of the gas flow through to a burner. A valve assembly according to Claim 5 wherein the metering device comprises a spindle having one or more recesses which co-operate with a resiliently biased member operably received in the recess. A valve assembly according to Claim 6 wherein a series of notches are formed in the spindle. A valve assembly according to Claim 5, 6 or 7 wherein the metering device comprises a second movable spindle co-operating with a locking device. A valve assembly according to Claim 8 wherein the second spindle can comprise a series of recesses and co-operate with a resiliently biased device comprising for example a spring and ball bearing arrangement. A valve assembly according to any preceding claim comprising means such as a micro-switch located on the valve assembly for deactivating a safety valve when the user locates the means for effecting movement of the valve closure or closures at a predetermined position. A valve assembly according to Claim 10 wherein, the micro-switch co-operates with the second spindle whereby the micro-switch is actuated when the second spindle is placed in a predetermined position such as withdrawn beyond the micro-switch contact. A valve assembly according to Claim 10 or 11 comprising a second micro-switch arranged to be operated in the same way, e.g. located at right angles to the first, and to energise additional circuits. A valve assembly according to any preceding Claim comprising means for stabilising the movement of a spindle used to effect movement of the valve closure or closures within the valve assembly. A valve assembly according to Claim 13 wherein stabilising means comprises a second spindle connected by an arm to the closure moving spindle and therefore provide relative rigidity to the system. A valve assembly according any preceding Claim wherein a valve closure is disposed intermediate two outlet channels which channels are substantially axially parallel to one another and lead to a larger diameter outlet in the body. A valve assembly according to Claim 15 comprising a large diameter outlet bore machined into the valve assembly body and two smaller diameter bores or channels drilled substantially parallel to one another and the axis of the larger diameter bore. A valve assembly according to any preceding claim comprising a series of outlets whereby flow may take place at any of a plurality of different rates, according to the setting of the spindle, wherein said outlets are connected by individual branch passages to a common flow passage communicating with said inlet, said control member extends along said common flow passage, and a series of separate flow control valves is disposed in said common flow passage and is arranged for sequential opening or sequential closing when said spindle is axially displaced in one or other direction. A valve assembly according to any preceding claim comprising a series of valve members each associated with a different one of said coaxial sections arranged to prevent flow from one of said sections to the next adjacent thereof, and means provided on said spindle so that in continued axial movement thereof in one direction said valve members are successively moved to and held in open positions, where flow to said next section(s) is possible, and in continued axial movement thereof in the opposition direction said valve members are successively restored to their closed positions. A valve assembly according to Claim 18 comprising a series of outlet passages each opening from a corresponding one of said sections arranged so as to provide flow at a different rate according to which valve(s) is/are in the open position. A gas valve assembly according to any preceding claim comprising a common flow passage having at least two axially successive sections of different diameters, a valve seat formed at the junction of two of said sections, a valve associated with said seat for preventing flow between said two sections, a valve stem for displacing said valve to allow flow, an outlet associated with said valve seat and connected to said common flow passage by a pair of branch passages each extending between a different one of said two sections and the said outlet, whereby flow may occur through said outlet at two different rates according to whether said valve is displaced or not. A valve assembly according to any preceding claim comprising a stepped main flow passage having a series of axial sections of successively greater cross sectional area, a separate valve closure element associated with each of at least some of the said sections and arranged when closed to prevent flow from one to the next of said sections, a valve stem extending along said passage, a series of couplings on said stem, each said coupling associable with a different one of said valve closure elements, and the spacing of said valve closure elements and couplings being such that axial movement of said stem displaces the valve closure elements from closed to open position or vice versa according to the direction of movement and in sequence along the passage, and a series of branch passages opening from said main passage connectable to the respective outlets whereby gas flow rate from the outlet(s) depends upon the open or closed status of the respective valves.

Inventors: GARCHA AMRIK SINGH, GARCHA, AMRIK SINGH
Applicants: CONCENTRIC CONTROLS LTD, CONCENTRIC CONTROLS LIMITED
Application year: 1998
Main classification: F23N1
IPC codes: F23N5, F23N1