[0001] This invention relates to gas cookers, and in particular to range style gas cookers
which include a gas hob. More particularly the invention relates to gas cookers which
are convertible between two or more fuel sources, and a method of conversion of such
gas cookers.
[0002] It is known to provide a gas cooker with an array of valves and the like for regulating
the gas flow between an inlet and a gas hob having a number of gas burners. These
valves may be provided to allow control of gas flow to each gas head, and are thus
provided in positions only usually accessible to trained personnel, or those with
high levels of knowhow.
[0003] In some cases, it is desired to convert a gas cooker to run on a different fuel.
For instance a gas cooker initially installed to run on natural gas, generally from
a mains supply, may be converted to use liquefied petroleum gas, hereinafter referred
to as "LPG", which is commonly provided from a gas tank. This conversion may also
be carried out in reverse. There are many reasons for such a conversion to take place,
including the costs of running each type of fuel, delivery or supply charges, and
the associated maintenance which is required to keep each type of cooker in safe working
order.
[0004] At present, the conversion process is a highly time-consuming, and therefore expensive,
process. Due to the differences in supply characteristics of different fuels, various
components must be removed or replaced. For example, natural gas is supplied to the
gas cooker at around 20 mb (2 kPa) gauge pressure whereas LPG may be supplied at 37
mb (3.7 kPa). Also taking into account the differing calorific values of the fuels,
the conversion must ensure that the correct flow rate of fuel is provided by the cooker.
In a conversion, it may therefore be necessary to replace the valves, also known as
burner jets, associated with each gas head and potentially also the gas regulator,
if required. As such, the conversion process may be laborious and expensive due to
the necessity to alter many components.
[0005] It is an object of the present invention to ameliorate the problems associated with
adapting a gas cooker for use with different gas sources.
[0006] In accordance with a first aspect of the invention there is provided a gas cooker
comprising: a gas hob having a plurality of gas heads; a gas regulator; a gas inlet
connected to the gas regulator for receiving an external gas supply via the gas regulator;
the gas inlet being connected to each gas head by a shared flow path for the transit
of gas received by the external gas supply; and flow control means for enabling a
gas flow to each gas head to be centrally modified.
[0007] As the use of different fuels may require different gas flows to be provided, the
flow control means enables efficient conversion of the gas cooker between configurations
suitable for different fuels. An easily adaptable feature, which allows central modification
of the gas flow, ensures that conversion may be quicker and therefore more cost-effective.
Additionally, minimal additional parts may be necessary depending on the specific
design of the flow control means, further enhancing the advantages of the invention.
[0008] Preferably, the flow control means may be adapted for enabling central modification
between at least a first gas flow for use with an LPG gas supply and a second gas
flow for use with a natural gas gas supply. As the most common conversion for gas
cookers is between LPG from a tank and natural gas from a mains supply, ensuring that
the flow control means is specifically adapted for use with these two gases is a clear
advantage.
[0009] The flow control means may form a part of the shared flow path. In a preferred embodiment,
the flow control means may include an adjustable valve having at least a first and
second setting. The first setting may be suitable for use with LPG and the second
setting may be suitable for use with natural gas.
[0010] Providing the flow control means with an adjustable valve having predefined first
and second settings means that it is a straightforward task to convert the gas cooker
between configurations suitable for use with different fuels. Additionally, by providing
the first and second settings as suitable for use with the two most common fuels between
which conversion is required, ensures that additional components for conversion may
not be required. These settings may be binary, such that the selection may only be
set between two predetermined settings.
[0011] Optionally, the adjustable valve may comprise a ball valve or buttery valve. Such
valves may commonly be utilised to adjust between different settings.
[0012] Additionally or alternatively, the flow control means may include a removable conduit
portion. Such a removable conduit portion may be releasably attachable to the conduits
by way of at least one fastener.
[0013] Removable conduit portions may be used to provide simple and quick exchange of parts
that allow different gas flows therethrough. By making these removable conduit portions
releasably attachable to the conduits, no welding or cutting may be necessary for
conversion, for example, further speeding up the process. Two different sized and/or
shaped removable conduits may be provided, each restricting fluid flow in a different
manner so as to provide the two flow rates. Each may define an orifice with a different
cross section area.
[0014] The flow control means may include a receiver having a cavity therein for the receipt
of a removable conduit portion. The cavity may be sealable by a blanking plate. Thus
a gas flow may be provided through the cavity. Alternatively, by inserting a removable
conduit portion into the cavity, different gas flows may be provided through the cavity.
Preferably, the flow control means may have a first gas flow when the removable conduit
portion is received within the cavity and a second gas flow when the removable conduit
portion is removed from the cavity.
[0015] The gas cooker may further comprise an aperture through which the flow control means
may be accessed. This aperture may provide the user with easy access to the flow control
means, in order to enable adjustment.
[0016] The aperture may be closable by way of a removable panel, which may require tools
for removal. Thus, accidental adjustment of the flow control means by an unskilled
person may be avoided. The gas cooker may further comprise a marking for indicating
the location of the flow control means. This may show a user where to find the flow
control means or where to make an opening in the gas cooker for access, if no aperture
is present.
[0017] The flow control means may be located at or adjacent to a wall of the gas cooker,
such that it may be easily accessed. Additionally or alternatively, the flow control
means may be accessible through a control panel of the gas cooker.
[0018] In accordance with a second aspect of the invention there is provided a method of
converting a gas cooker between a first fuel and a second fuel, the method comprising
the steps of: a] providing a gas cooker as claimed in any one of the preceding claims;
b] adapting the flow control means such that the gas flow is modified between a first
gas flow suitable for use with a first fuel and a second gas flow suitable for use
with a second fuel.
[0019] Preferably, the first fuel may be LPG and the second fuel may be natural gas.
[0020] The flow control means may be adapted by switching the flow control means between
a first and second setting, the first and second setting resulting in the flow control
means being suitable for providing a first and second gas flow, respectively.
[0021] Additionally, the flow control means may be adapted by insertion and/or removal of
a removable conduit portion.
[0022] There will now be described, by way of example only, an embodiment of a gas cooker
in accordance with the present invention with reference to the accompanying drawings,
in which:
Figure 1 depicts a gas cooker in accordance with the first aspect of the invention, including
a flow control means;
Figure 2 shows a further flow control means for use with the gas cooker of Figure 1;
Figure 3 shows yet another flow control means for use with the gas cooker of Figure 1.
[0023] An embodiment of a gas cooker 100 in accordance with the present invention is shown
in Figure 1. The gas cooker 100 includes a gas hob 102 which has a plurality of gas
heads 104 or gas burners, in this case, three. The gas hob 102 is located at an upper
surface 106 of the gas cooker 100, providing a surface for cooking. Two ovens 108
are also shown. A greater number of ovens 108, for instance three or four, could be
present on the gas cooker 100, if desired, or alternatively a single oven or no oven
at all could be present. In the present embodiment these ovens 108 are electrically
operated, the workings and any further description of which are omitted, for clarity.
[0024] A gas inlet 110 is provided within or adjacent to the gas cooker 100 for connection
to a gas supply (not shown). The gas supply connects to the inlet 110 via a gas regulator
112, which ensures supplied gas, which may come from a source with fluctuating pressure,
is provided to the cooker 100 at a constant or substantially constant pressure. The
gas supply may be LPG, for instance from a tank local to the cooker, or natural gas,
which may commonly be provided from a mains supply. The gas inlet 110 is connected
to each gas head 104 by a network of conduits 114. Three gas heads 104 are provided
in the depicted embodiment, but a greater or lesser number may be provided, dependent
on the design and desired characteristics of the gas cooker. For instance, on smaller
cookers, only one or two gas heads may be required, but up to six or eight gas heads
may be provided to allow a greater space for cooking. A greater number of gas heads
is also possible.
[0025] The conduits 114 connecting the gas inlet 110 to the gas heads 104 include a shared
duct 116 defining a shared flow path for the transit of gas between the gas inlet
110 and the gas heads 104, and multiple branch ducts 118 which split from the shared
duct 116 to transport gas directly to each gas head 104. At least one junction 120
is therefore provided, interposed between the shared duct 116 and the branch ducts
118 to split the gas flow between the gas heads 104.
[0026] In practice, the conduits 114 which interconnect the gas inlet 110 and the gas heads
104 may be specifically designed for the transit of a certain type of gas, which may
be delivered at a specific pressure, and/or flow rate. For instance, whilst the regulator
112 may deliver the gas at a safe pressure to the cooker 100, it may be necessary
for the pressure, flow rate, or other flow characteristic to be further modified by
the conduits 114. The particular gas flow needed is a product of not only the requirements
of the cooker 100, but also the fuel which is provided thereto. Thus, if the gas cooker
100 is to be converted for use with another gas which is different from the gas for
which it is originally designed, it may be necessary to control the gas flow to alter
the pressure and/or flow rate from those which were originally specified. Therefore,
partway along the shared duct 116 of the present embodiment is provided a flow control
means, indicated as box A, for enabling the centralised or unified modification of
the gas flow.
[0027] In the present embodiment, the flow control means A comprises an adjustable valve
122 having two predetermined binary settings, which may be switched between by manual
actuation of a selector, which in this case is a rotary knob 124. A first setting
may provide a gas flow suitable for use with LPG, whilst a second setting may provide
a gas flow suitable for use with natural gas. In the present embodiment, the adjustable
valve 122 is a gate valve, but other adjustable valves may also be used, such as a
ball valve, globe valve, or butterfly valve. Other forms of adjustable valve may also
be used in addition to or in place of the aforementioned types.
[0028] The adjustable valve 122, if required, may also have further settings such as a third
or fourth setting. Such settings could be useable in conjunction with other fuel types,
such as butane or propane. Additionally, whilst the first and second setting on the
present adjustable valve may be suitable for use with LPG and natural gas, they may
instead be suitable for use with any other combination of two fuels.
[0029] Furthermore, whilst a rotary knob 124 is manually actuatable for switching between
settings, in the present embodiment, other switching means may also be used in its
place or in addition. For instance a slide switch or screw may be present. It may
also be desired for the switching to be electrically achieved, in which case an electric
actuator may be used in conjunction with the adjustable valve, for ease of use.
[0030] An aperture 126 may be provided through the gas cooker to enable access to the flow
control means A. Preferably, the flow control means A will be easily accessible such
that it may be accessed when required, but suitably remote or hidden such that it
may not be tampered with accidentally. As such, the aperture 126 provided for accessing
the flow control means A in the present embodiment is provided at or adjacent to a
wall 128 of the gas cooker and may have a cover 130 which closes the aperture 128,
hiding the flow control means A. The aperture 126 may instead be provided on the back
or other side of the gas cooker to further prevent accidental actuation or misuse
of the flow control means by an unskilled person. It may be desired to secure the
cover such that it is difficult to remove. Providing it in such a way may further
prevent tampering. Such methods could include ensuring that the cover requires tools
to be removed, for instance by bolting the cover to the gas cooker.
[0031] Given that the flow control means A may only be required to be used once in the life
of the cooker 100, when converting from one fuel to another, an aperture 126 may not
be required for access of the flow control means A. For instance, the flow control
means may be accessible through a removable panel or through another opening in the
gas cooker. Alternatively, the flow control means may be provided external to the
gas cooker. In this case it may be advantageous to provide the flow control means
such that it is still hidden from view, for instance between the rear of the gas cooker
and a wall adjacent to which the cooker is positioned. Alternatively, or in addition,
a marking may be provided to indicate to a skilled person, such as an engineer, where
the flow control means is located. In such a manner, when it comes to conversion of
the cooker between fuels, the engineer may remove a portion of the cooker, for instance
using a drill or other means, in order to access the flow control means. The gas cooker
may then be repaired once the conversion process is complete, if necessary.
[0032] The flow control means may otherwise be located such that it is accessible through
a control panel which houses other parts which may require maintenance, such that
an engineer may readily access the flow control means, when necessary. Alternative
positions or locations for the flow control means may also be used, the possibilities
of which are not intended to be limited by the examples discussed herein.
[0033] The flow control means A allows swift and relatively simple tuning or adaptation
of the gas flow through the conduits. In particular, as the flow control means A is,
in the present embodiment, located on the shared duct 116 which is in series with
each of the gas heads 104, its adaptation results in a change in flow to each of the
gas heads 104 to which it is attached.
[0034] In practice, in order to convert the gas cooker 100 for use with a different fuel,
the flow control means A may be adapted by modification of its flow factor. The flow
factor is a relative measure of its efficiency at allowing fluid flow. Generally,
the flow factor may be altered by a change in the internal diameter of the flow control
means or the cross-section of an orifice or other flow-affecting feature within the
flow control means.
[0035] As shown in Figure 1, in addition to the flow control means A, tuning valves 132
are also provided in series with the branch ducts 118 which lead to each gas head
104. These tuning valves 132 may further modify the gas flow to ensure that the gas
flow is suitable for each individual gas head 104. Thus, the power of one gas head
may be adjusted separately to that of the other gas heads. The cooker 100 having the
ability to further tune the gas flow is advantageous, but may not be intrinsic to
the present invention. For example, the main conversion will be managed by the flow
control means A, which affects a plurality of the gas heads 104, whilst the tuning
valves 132 may not need to be adjusted at all. Although in the present embodiment
tuning valves 132 are shown in conjunction with each branch duct 118, they may only
be provided in conjunction with a selection of branch ducts or may be omitted completely,
if their presence is not required.
[0036] Although the conversion process has thus far been discussed with reference only to
the flow control means A, which is provided to simplify the process, the conversion
process need not necessarily be limited to adaptation of the flow control means A.
It may also be necessary, for instance, to adjust or replace the gas regulator 112,
such that the correct inlet pressure is provided to the flow control means A and conduits
114. In this case, it may be preferable to provide the regulator 112 external to the
cooker 100 to allow easy access, or to provide an access aperture to the regulator
112, for instance. Other components may also be removed, replaced, or adapted, as
necessary.
[0037] In figure 2, another embodiment of a flow control means A is depicted. Similar or
identical features are given similar or identical references, and further detailed
description of such features may be omitted, for clarity. This second embodiment includes
a removable conduit portion 134. The removable conduit portion 134 is in this case
a pipe 136 having a first internal diameter 138a. The first internal diameter 138a
of the pipe 136 will have an effect on the flow through the removable conduit portion
134. The removable conduit portion 134 may also include other flow control devices
in addition to or in place of the pipe 136, such as valves, orifices, constrictions,
or other such devices. It is also foreseeable for the removable conduit portion 134
to include an adjustable valve or the like, as in Figure 1, for example.
[0038] The flow control means A also includes two fasteners 140, in this case screw fasteners,
which interconnect the removable conduit portion 134 and the shared duct 116. Whilst
screw fasteners are shown, other fasteners may also be used, such as press-fit fastenings,
clips, or grips. A greater or lesser number of fasteners may also be present, the
number of which is only limited by the physical requirements of the system.
[0039] As indicated by arrows X and Y, the removable conduit portion 134 may be removed
and replaced by a further removable conduit portion 142. As shown, the further removable
conduit portion 142 has a second internal diameter 138b which is smaller than the
first internal diameter 138a. As such, when the exchange of the components is made,
the flow control means A will have a different effect on the gas flow. The second
internal diameter 138b may also be greater than the first internal diameter 138a,
if a different gas flow is required.
[0040] A third embodiment of the flow control means A is down in Figure 3. Similar or identical
features are given similar or identical references, and further detailed description
of such features may be omitted, for clarity. The flow control means A includes a
receiver 144 having a cavity 146 housing two fasteners 140 therein, and a blanking
plate 148. The blanking plate 148 covers a receiver aperture 150, sealing the cavity
146. As shown, gas entering the receiver 144 may flow through the cavity 146, between
the fasteners 140. Releasably insertable within the cavity 146 is a removable conduit
portion 134 which may include a valve, orifice, constriction, or other flow-altering
mechanism.
[0041] In order to vary the gas flow through the flow control means A, the removable conduit
portion 134 may be inserted into or removed from the cavity 146, as depicted by arrow
Z. When the removable conduit portion 134 is in an inserted condition, the flow control
means A will have a first gas flow, and when it is in a removed condition, the flow
control means A will have a second gas flow. Multiple different removable conduit
portions 134 may be available for insertion, the choice between which may be made
by a skilled person such as an engineer, such that a suitable gas flow is enabled
for the required conversion.
[0042] Although a removable conduit portion 134 is described herein as being insertable
to vary the flow through the receiver 144, other flow affecting means may also be
insertable in place of or in addition to the removable conduit portion 134. For instance,
an orifice plate could be inserted into the cavity, or instead a constrictor could
be inserted to change the shape or dimensions of the cavity 146 itself. Other devices
for varying the flow through the receiver could also be utilised, of which the skilled
person will be aware.
[0043] Though included as separate embodiments, each feature of the described flow control
means A may be used either separately or in conjunction with each other. For instance,
the adjustable valve 122 may be used in addition to a removable conduit portion 134,
or may itself be part of an adjustable removable conduit portion. The flow control
means A described herein are thus examples only, and are not limiting to the possible
configurations of flow control means A.
1. A gas cooker comprising:
a gas hob having a plurality of gas heads;
a gas regulator;
a gas inlet connected to the gas regulator for receiving an external gas supply via
the gas regulator;
the gas inlet being connected to each gas head by a shared flow path for the transit
of gas received by the external gas supply; and
flow control means for enabling a gas flow to each gas head to be centrally modified.
2. A gas cooker as claimed in claim 1, wherein the flow controls means is adapted for
enabling central modification between at least a first gas flow for use with an LPG
gas supply and a second gas flow for use with a natural gas gas supply.
3. A gas cooker as claimed in claim 1 or claim 2, wherein the flow control means forms
a part of the shared flow path.
4. A gas cooker as claimed in any one of claims 1 to 3, wherein the flow control means
includes an adjustable valve, having at least a first and second setting.
5. A gas cooker as claimed in claim 4, wherein the adjustable valve has binary first
and second settings.
6. A gas cooker as claimed in claim 4 or claim 5, wherein the first setting is suitable
for use with LPG and the second setting is suitable for use with natural gas.
7. A gas cooker as claimed in any one of claims 4 to 6, wherein the adjustable valve
comprises a ball valve or butterfly valve.
8. A gas cooker as claimed in any one of the preceding claims, wherein the flow control
means includes a removable conduit portion.
9. A gas cooker as claimed in claim 8, wherein the flow control means includes a receiver
having a cavity therein for the receipt of the removable conduit portion.
10. A gas cooker as claimed in claim 9, wherein the cavity is sealable by a blanking plate.
11. A gas cooker as claimed in claim 9 or claim 10, wherein the flow control means has
a first gas flow when the removable conduit portion is received within the cavity
and a second gas flow when the removable conduit portion is removed from the cavity.
12. A gas cooker as claimed in any one of the preceding claims, further comprising an
aperture through which the flow control means may be accessed.
13. A gas cooker as claimed in claim 12, wherein the aperture is closable by way of a
removable panel.
14. A gas cooker as claimed in any one of the preceding claims, further comprising a marking
for indicating the location of the flow control means.
15. A gas cooker as claimed in any one of the preceding claims, wherein the flow control
means is located at or adjacent to a wall of the gas cooker.
16. A gas cooker as claimed in any one of the preceding claims, wherein the flow control
means is accessible through a control panel.
17. A gas cooker substantially as hereinbefore described with reference to Figure 1, Figure
2, or Figure 3 of the accompanying drawings.
18. A method of converting a gas cooker between a first fuel and a second fuel, the method
comprising the steps of:
a] providing a gas cooker as claimed in any one of the preceding claims;
b] adapting the flow control means such that the gas flow is modified between a first
gas flow suitable for use with a first fuel and a second gas flow suitable for use
with a second fuel.
19. A method as claimed in claim 18, wherein the first fuel is LPG and the second fuel
is natural gas.
20. A method as claimed in claim 18 or claim 19, wherein the flow control means is adapted
by switching the flow control means between a binary first and second setting, the
first and second setting resulting in the flow control means being suitable for providing
a first and second gas flow, respectively.
21. A method as claimed in any one of claims 18 to 20, wherein the flow control means
is adapted by insertion and/or removal of a removable conduit portion.