FIELD OF THE INVENTION

The invention relates to control valves for controlling the flow of gas in a gas line, and in particular to a motorised control valve for opening and closing the component parts of a control valve for controlling the flow of gas in a gas line.

BACKGROUND TO THE INVENTION

There is a requirement for gas control valves, or gas shut-off valves, to control and regulate gas usage with accuracy and reliability in order to reduce gas consumption. There is also a requirement to provide a high integrity gas seal in a gas control valve that will be effective under a range of pressures, such as the varying pressures found in a national gas distribution system and will do so in a way which is cost-effective, in particular when using mass produced components such as valves and valve seats. These criteria must be capable of being fulfilled over a long-time span as installations, such as in domestic premises, may not be regularly monitored or may be abandoned. There is also a requirement that should maintenance, such as preventive maintenance, be required of the valve then it can be readily undertaken so as to prolong valve life. Mass produced components can be readily provided using plastics injection moulding however this provides the potential for distortion in a valve seat or valve due to cooling of the injection moulding material after injection and also damage, such as scratching on the components prior to assembly. Further, with the advent of microcontrollers in even simple gas appliances there is a need to provide effective monitoring of sealing efficiency of the gas valve.

WO2018/130422 discloses an axial control valve for controlling the volume flow in a gas line, having a housing which has an upstream inflow opening that adjoins a pre-chamber formed in the housing and is delimited radially outwards at least in some sections by an annular wall provided with passage openings. The housing is equipped with a continuous channel which is arranged outside of the annular wall and which opens into an outflow opening. A valve element can be adjusted within the pre-chamber along a longitudinal axis of the axial control valve and can be brought into sealing contact with an inner wall of the annular wall, whereby at least some of the passage openings can be closed. US2010/140520 discloses a gas control valve and method of controlling a gas control valve to provide infinite adjustability, wherein the gas control valve defines a fluid flow path and a flow adjustment arrangement within the fluid flow path has a plurality of discrete open configurations. Each discrete open configuration establishes a different flow rate through the fluid flow path. A controller operatively cyclically alternates the flow adjustment arrangement between different ones of the discrete configurations to provide an average flow rate through the fluid flow path that is between the flow rates permitted by the different ones of the discrete open configurations.

GB 1400290 A discloses a gas control valve powered by an electric motor in which the electric motor drives a threaded spindle which comprises a flywheel so as to provide improved closing of the valve.

GB 495935 A discloses a gas control valve powered by an electric motor in which the electric motor drives a threaded spindle which moves a valve member guided by a sliding pivot.

CN 107202169 A discloses a water control valve powered by an electric motor in which the electric motor drives a threaded spindle which moves a needle valve into an orifice to control flow.

It would therefore be advantageous to have a motorised gas shut-off valve for smart meter applications, suitable for installation to either the outlet or inlet port with a customer specific meter interface, to regulate gas usage.

It would be further advantageous if the gas control valve could be applied across a diverse range of utilities meter applications, as well as utilising the drive mechanism in other positional locking device uses.

It is yet further advantageous to provide a gas valve with affective sealing means against mass produced, such as injection moulded, components and which can be quickly and easily repaired if required. SUMMARY OF THE INVENTION

The invention is set out in accordance with the appended claims. The invention is a control valve assembly for controlling the flow of gas in a gas line having an inlet port and an outlet port, and a fluid flow path defined between the inlet port and outlet port, the control valve comprising: a motor mounted in a housing, the motor having a threaded spindle extending from a surface of the housing, the surface further comprising at least one recess therein; a valve member threadedly mounted on the spindle for translating the valve member upon rotation of the spindle, the valve member having a first face opposing the surface of the housing and a second face, the first and second faces being separated by a rim, the valve member having at least one elongate guide pin, each of the at least one guide pins extending away from the first face of the valve member towards the housing and being shaped and dimensioned to be received by the corresponding at least one recess in the housing; one of the at least one guide pins being configured to engage a switch in the housing when the valve member is in a fully open position; a resiliently deformable sealing cap formed from an elastomeric polymer and attached to the valve member at the rim and having a portion extending away from the second face of the valve member; a gas supply closure port attached to the housing having a tubular body and defining a valve seat to receive the sealing cap for closing the valve; wherein, in use, the valve member is movable between a first open position, remote from the valve seat, and a second closed position, abutting the valve seat.

The invention also comprises a method of preventing the flow of gas in a gas line using the control valve assembly described herein, the method comprising the steps of: actuating the motor to extend the valve member towards the second position so as to position the sealing cap against the valve seat of the gas closure port; and detecting current flow through the motor with a controller to determine that the valve member is in the second position.

The invention further comprises a method of allowing the flow of gas in a gas line using the control valve assembly described herein, the method comprising the steps of: actuating the motor to retract the valve member towards the first position so as to remove the sealing cap from the valve seat of the gas closure port; and sensing that the valve member is in the first position by actuation of the switch by one of the at least one guide pins.

The skilled person will be aware that an ‘inlet port’, an ‘outlet port’ and a ‘flow path’ defined between the inlet port and outlet port do not form part of the invention. The control valve assembly is suitable for, and intended to be used, in connection with an ‘inlet port’, an ‘outlet port’ and a ‘flow path’ defined between the inlet port and outlet port of a variety of suitably available apparatus. For example, the control valve of the present invention may be positioned within an existing gas flow line, or may be attached to additional components defining an ‘inlet port’ and ‘outlet port’, according to a consumer’s wishes. In particular, the control valve of the present invention may be used with smart meters for controlling the amount and flow of gas in a gas flow line. The use of such terms has been provided for the assistance of the skilled person in understanding the operation of the control valve assembly, and in particular with regards the orientation of any technical features that the invention comprises, since it is anticipated that the control valve assembly may be used in a variety of different orientations depending on the technical requirements of the particular application it is intended for.

For the avoidance of any doubt, it is anticipated that the control valve assembly is positioned in a gas flow line with the gas closure port positioned upstream from the housing and with the flow of gas entering from an inlet port towards the gas closure port prior and being directed over the surface of the sealing cap and moving downstream to an outlet port. The first open position, defined herein, is then downstream of the second closed position for the avoidance of any doubt. A skilled person will appreciate that it is equally envisaged that the gas closure port could be positioned in a different orientation within a gas flow line depending upon requirements.

Preferably, the control valve assembly further comprises a controller for actuating the motor to translate the valve member between the open and closed positions, and any intermediate position therebetween, the controller sensing a fully open position by actuation of the switch, and a fully closed position by detecting current flow to the motor when the valve member is actuated in a closing direction. This allows a minimum number of components to be used to achieve a fully working valve, whilst retaining the feature of a safety redundancy in the form of a switch coupled to the sensing of the current flowing when the motor is actuated. The switch can be used to sense the flow of current when the valve member is in the open position.

Preferably, the valve seat is attached to the housing by means of a collar, having a circular cross-section, and being offset from the valve seat by a series of elongate supports. The modular construction of the housing and collar allows the collar, and hence valve seat to be easily detached and removed from one another, if it becomes necessary to replace the sealing cap due to wear and tear. Preferably at least two elongate supports are used to maintain the off-set position of the valve seat from the housing, although it is envisaged that for structural purposes, the collar comprises preferably at least three, or at least four, elongate supports.

Preferably, the valve member is a disc and the valve seat are circular. The advantage of cooperatively matching valve seat to the valve member is that an improved seal is formed between the two when the valve member is adjacent the valve seat in the closed position to prevent the flow of gas in a gas line.

Preferably, the valve member comprises a central boss threadedly mounted on the spindle, and optionally one or more strengthening ribs extending radially from the boss on the first or second face of the valve member. The presence of a central boss with optionally one or more strengthening ribs provides for a more robust construction, whilst at the same time keeping the weight of the valve seat down to reduce any problems with inertia in use.

The resiliently deformable sealing cap, the sealing cap, which is attached to the valve member at the rim is a cap, that is it preferably covers a whole of one face of the valve member. As such only seal between the valve seat and the sealing cap is required for a seal.

Preferably, the portion of the sealing cap extending away from the second face culminating in or optionally defines a substantially hemispherical central projection. A substantially hemispherical central projection improves the aerodynamic shape of the sealing cap and improves the flow of gas in the gas line. When culminating in the hemispherical central projection the valve cap between that projection and the rim of the sealing cap is a concave, which may be thought of as frusto conical (when of circular cross section) portion with a concave side or periphery. This provides optimal guidance of gas over the valve member to the gap, when open, between the valve members and the valve seat.

Preferably, the sealing cap is attached to the first face of the valve member by an inwardly projecting radial flange. That flange is preferably opposing the side of the sealing cap covering one face of the valve member. This means that separate attachment and/or separation means are not required to allow the sealing cap to attach to the rim of the valve member. The flexibility of the sealing cap allows it to be inserted over the rim of the valve member so that the inwardly projecting radial flange attaches itself to the underside of the rim on what is the first surface of the valve member.

Preferably, the sealing cap is shaped and dimensioned to the rim of the valve member and the sealing cap extends over the second face of the valve member so as to accommodate the threaded spindle when the valve member is in the open position. This allows the efficient sealing of the thread to the valve member, as well as the valve member to the valve seat, effectively using a single component, the sealing cap, in order to control, limit or permit the flow of gas through the control valve assembly or gas flow line. The arrangement of placing the sealing over the rim provides a quick and easy method to locate the sealing cap on the valve, so that it locates properly against the valve seat and the valve is closed. Further, as the sealing is elastomeric it also provides a simple and effective means to heal the valve seat of the valve ready for simple replacements, such as during in situ preventive maintenance or repair. In particular, due to the use of the elastomeric material distortion of the valve or the valve seat over time, and such valves are typically employed on 5 to 20 year time spans, is accommodated as the elastomeric material can distort so as to provide an effective seal even when the geometry of the valve contact faces changes over time. In this respect the sealing cap is preferably dimensioned so that when secured on, i.e. around, the rim of the valve member it is in tension, i.e. resiliently deformed as this acts to even out he material of the cap across the width (between the edges) of the valve member. The tensioning is preferably resulting from a strain in the range 10,000 to 30,000 ppm.

Preferably, the central projection deforms to a point when the valve member is in the second position. It is to be understood that in the present context of the present invention a point means, pointed, rather than a sharp or one-dimensional point. When the spindle fully extends so that the valve member is in the second closed position, it abuts the interior of the sealing cap and the central projection of the sealing cap is pushed further away from the second surface of the valve member by the spindle. An analogy to help visualise this is the movement of a tent (the cap) being flat on the ground and raised by a single central pole (the spindle). As such the cap may be coplanar with the face of the valve member in its unextended state. This previously mentioned movement causes the central projection to deform into a pointed projection (or maintain it in that geometry if it is already in that position), which improves the aerodynamics of the gas flowing through the control valve assembly. Preferably the end of the spindle is smooth to prevent the spindle from rupturing the sealing cap when it abuts and deforms the central projection. This prevents the sealing cap from having to be replaced due to wear at this point. In addition, the pushing of the spindle into the seal cap acts to self-centre the sealing cap, such as after a replacement or new has been fitted manually, thus facilitating maintenance.

Preferably, the sealing cap is formed from an elastomeric polymer. An elastomeric polymer is resiliently deformable. This allows the sealing cap to seal itself against the, preferably, polymeric surfaces of other components in the control valve assembly. As mentioned previously this also has the advantage that distortions, damage or imperfections in the valve or valve seat can be accommodated so as to provide an effective gas seal. Therefore, rather than having to use machined metal components, in particular for the valve seat injection moulded plastic components can be readily used even to the extent that imperfections from mould marks can be accommodated. This greatly improves efficiency both in terms of materials and production for a valve using the present invention. Furthermore, the use of an elastomeric sealing cap against an injection moulded plastic gives improved ceiling as the surface energy of a polymer services and hence the difference in surface energy between services with polymer on a polymer is similar and a tight seal can be readily obtained with less force the mail the other rides required. The surface energy difference between the polymers is preferably less than 100mJ/m ² . Whilst this can be best achieved by having two polymers, the polymer for the sealing cap and the valve seat, made of the same material this is rarely possible as one material is preferably elastomeric and the other material is preferably rigid. Hence, the optimum can be found with the surface energy difference to be in the polymers is 14 to 27mJ/m ² , such as can be achieved by a combination of a Silicone (20mJ/m2) or PTFE (19mJ/m2) polymer for the elastomeric sealing cap and ABS (35mJ/m2) or Nylon (46mJ/m ² ) for the valve seat. Indeed, such a different is preferable since adhesion between the sealing cap and the valve seat is avoided as a lower surface energy difference can (as with adhesive’s) lead to good adhesion. Surface energy values are widely available and tabulated for most common materials.

Preferably, the sealing cap is formed from silicone rubber or elastomeric PTFE. This prevents the sealing cap from welding together with other polymeric components even if the valve seat remains in the closed position, or closed hard, for prolonged periods of time.

Preferably, the collar further comprises a plurality of resilient protuberances for detachably latching the collar to the housing. This allows the housing and the collar to be easily detached from each other if it becomes necessary to replace the sealing cap due to wear and tear.

Preferably, an exterior surface of the sealing cap is shaped and dimensioned to the interior surface of a portion of the valve seat. This allows the sealing cap to control or limit the flow of gas through the control valve assembly if the two surfaces substantially mirror each other and are in contact with each other, when the valve member is in the closed position. It further allows the sealing cap to permit the flow of gas through the control valve assembly when the valve member is in the open position.

Preferably, the tubular body is circular in cross-section and comprises a first tubular region having a first radial diameter. The skilled person will be aware that the tubular body may comprise alternative cross-sections (square, hexagonal etc.), but the advantage of a circular cross-section is that more predictable flow characteristics can be obtained, and that there is generally less turbulence created in comparison with alternative tubular cross-sections. The circular cross-section, is preferable for the present invention as the spindle is preferably central to the valve member and hence the force exerted by the spindle on the valve member and the valve member, by the cap, exerted on the valve seat is therefore evenly distributed and a more efficient seal, having a similar pressure at all points is therefore created. This is important because distortions accommodated by the cap of the present invention are normally not known in advance so there will be an inherent distribution of pressure around the valve seat even if this is not intended. This is particular so with injection moulded components, which for the reasons proves dimensioned are preferably used. Preferably, the tubular body comprises a second tubular region having a second radial diameter upstream from the first tubular region, wherein the first radial diameter is greater than the second radial diameter, the first and second regions being connected by a frustoconical tubular region between the first and second tubular regions. The frustoconical tubular region created between the first and second tubular regions mirrors the taper of the central projection of the sealing cap. This allows improved aerodynamics of the gas flowing in the gas line.

Preferably, the valve seat to receive the sealing cap is a ledge in the interior of the first tubular region. A ledge minimally disrupts the flow of gas in the gas line. Preferably the valve seat to receive the sealing cap is a sloped ledge in the interior of the first tubular region. A sloped ledge has the improved benefit over a regular ledge in that it does not disrupt the flow of gas in the gas line.

Preferably, the motor is a stepper motor. This allows the motor to more accurately control the position of the spindle when the valve member is at one or more of the intermediate positions between the closed and open positions.

The invention as described above solves the problems of providing simple and effective ceiling in a gas valve. This is particularly so when the gas valve is constructed using injection moulded plastics components, in particular the valve seat and/or the valve. This is also so as imperfections in the valve and valve seat can be accommodated. Further, by suitable choice materials effective ceiling at lower pressures can be obtained whilst avoiding adhesion, such as due to prolonged valve closure, between valve and valve seat.

Further advantageous aspects of the invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments and with reference to the accompanying drawings.

DRAWINGS

Specific embodiments of the invention are described by way of example and with reference to the accompanying drawings in which like numerals are used to indicate like parts and in which: Figure la shows a side view of the valve member threadedly mounted in the housing of the control valve assembly;

Figure lb shows an isometric view of the control valve assembly of Figure la;

Figure 2a shows a side view of the valve member threadedly mounted in the housing of the control valve assembly with the sealing cap attached;

Figure 2b shows an isometric view of the control valve assembly of Figure lb;

Figure 3 shows an isometric view of the control valve assembly of Figure 2b with a detachable gas supply closure port;

Figure 4 shows an alternative isometric view of the control valve assembly of Figure 3; and Figure 5 shows an isometric view of the control valve assembly of Figure 4 with the gas supply closure port attached to the housing.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, Figure la shows an embodiment of a control valve assembly 1 according to the invention as described in more detail below.

The control valve assembly comprises a stepper motor 2 (not shown) mounted in a housing 4, the motor 2 having a threaded spindle 6 extending from a surface 8 of the housing 4.

Mounted at an end of the spindle 6 is a circular disc-shaped valve member 10 defining a central boss 18 and having a first face 12 opposing the surface 8 of the housing 4. The valve member 10 has a second face 14 opposing the first face 12, wherein the first 12 and second 14 faces are separated by a rim 16. The valve member 10 has a series of strengthening ribs 20 extending radially from the boss 18 on the first 12 or second 14 face of the valve member 10. Figure la shows four strengthening ribs 20 extending radially away from the boss 18.

The valve member 10 has two elongate guide pins 22 extending away from the first face 12 of the valve member 10 towards the housing 4. Each of the elongate guide pins 22 are shaped and dimensioned to be received by corresponding recesses 24 in the housing 4.

Figure la shows the valve member 10 in what is defined as a first, or open, position, i.e. where the spindle 6 and valve member 10 are fully retracted into the housing 4. The corresponding second, or closed, position is when the spindle 6 and valve member 10 are fully extended from the housing 4. The control valve assembly 1 further comprises a controller (not shown) mounted within the housing 4 for actuating the motor 2 to translate the valve member 10 between the open and closed positions, and any intermediate position therebetween. The controller is able to sense a fully open position by actuation of a switch 30 (not shown) within the housing 4, and a fully closed position by detecting current flow to the motor 2 when the valve member 10 is actuated in a closing direction.

Figure lb shows an alternative (isometric) view of the control valve assembly 1 as described above in Figure la.

Figure 2 shows the control valve assembly 1 as described above for Figures la and lb, where the valve member 10 further comprises a sealing cap 26 attached to the valve member 10.

The sealing cap 26 is formed from an elastomeric polymeric material, and is attached to the rim 16 of the valve member 10 and secured against the first face 12 of the valve member 10 by a portion of the sealing cap 26 defining an inwardly projecting radial flange (not shown). Silicone rubber is a good material to form the sealing cap 26 from. The sealing cap 26 is shaped and dimensioned to the valve member 10, and a portion of the sealing cap 26 extends away from the second face 14 defining a substantially hemispherical central projection 28. The sealing cap 26 extends over the second face 14 of the valve member 10 so as to accommodate the threaded spindle 6 when the valve member 10 is in the open position. In operation, as the valve member 10 and spindle 6 are extended out of the housing 4 through a range of intermediate positions until they are at the second position, the end of the spindle 6 impacts on the inner surface of the sealing cap 26 and deforms the central projection 28 to a point.

Figure 2b shows an alternative (isometric) view of the control valve assembly as described above in Figure 2a.

Figure 3 shows the embodiment of the invention according to the previous Figures, but further comprising a gas closure port 30, which defines a valve seat 32, for receiving the sealing cap 26 and closing the control valve assembly. The gas closure port 30 has a collar 34 being offset from the valve seat 32 by a series of four elongate supports 36. The collar 34 further comprises a plurality of resilient protuberances 38 for detachably latching the collar 34 to the housing 4. Figure 3 shows four equally spaced protuberances 38 mounted on the housing 4 for detachably releasing the collar 34 to the housing 4.

The tubular body of the gas closure port 30 is circular in cross-section and comprises a first tubular region 40 having a first radial diameter, and a second tubular region 42 having a second radial diameter upstream from the first tubular region 40. The first radial diameter is greater than the second radial diameter, with the first and second regions being connected by a frustoconical tubular region 44 between the first 40 and second tubular regions 42. In particular, the valve seat 32 is a ledge in the interior of the first tubular region 40 to receive the sealing cap 26 when the valve member 10 and spindle 6 are in the second position.

Figure 4 shows an alternative view of the embodiment of the invention as described above in Figure 3. It can be seen from Figure 4 that an exterior surface of the sealing cap 26 is shaped and dimensioned to the interior surface of a portion of the valve seat 32 for closing the valve when the valve member is in the second position. Gas, entering from an inlet port, is prevented from flowing within the gas line when the sealing cap 26 is adjacent the valve seat 32 of the gas closure port 30 so as to form an airtight seal between the sealing cap 26 and the valve seat 32.

Finally, Figure 5 shows the control valve assembly 1 of the invention, where the gas closure port 30 is attached to the housing 4. The valve member 10 is in the first, or open, position, with the spindle 6 and valve member 10 being fully retracted into the housing 4.

In use, the control valve assembly 1 of the invention prevents the flow of gas in a gas line by actuating the motor 2 to extend the valve member 10 towards the second position so as to position the sealing cap 26 against the valve seat 32 of the gas closure port 30, and detecting current flow through the motor 2 with a controller to determine that the valve member 26 is in the second position.

Gas flowing within the gas line is then prevented from flowing through the gas closure port 30 due to the position of the sealing cap 26 is adjacent the valve seat 32 of the gas closure port 30.

In use, the control valve assembly 1 of the invention allows the flow of gas in a gas line by actuating the motor 2 to retract the valve member 10 towards the first position so as to remove the sealing cap 26 from the valve seat 32 of the gas closure port 30, and sensing that the valve member 10 is in the first position by actuation of the switch by one of the at least one guide pins 22.

Gas is then allowed to flow within the gas line through the gas closure port 30 due to the position of the sealing cap 26 remote from the valve seat 32 of the gas closure port 30.

The invention is not limited to the embodiments disclosed herein which may be modified or varied without departing from the scope of the invention.