AU2009201248B2 - Air-cooled chinese cooking table for woks - Google Patents

Abstract

A Chinese cooking table top for woks is cooled by a combination of integers which co-operate to produce table-top cooling air convection air flow via an air gap created between a gas ring burner combustion gas outlet and a height-adjustable removable trivet instead of using a conventional cooling water curtain flowing continuously across the hot table top; removable, cylindrical heat shields are also provided to prevent combustion gases heating the underside of the table and at least one of the shields provides an adjustable secondary cooling air flow gap between a trivet placed on the table top and the opening at the top of and surrounding the combustion zone

Description

3 1 l r AUSTRALIA 20 09 Patents Act 1990-2001 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title AIR-COOLED CHINESE COOKING TABLE FOR WOKS Name of Applicant COMMERCIAL FOOD MACHINERY VIC.PTY.LTD. The following statement is a full description of this invention including the best method of performance known to us: John L Davies, Patent Attorney For And Behalf of Applicant -1 This invention relates in general to commercial cooking equipment ad relates in particular to a waterless convection air cooled cooking table for cooking with woks over ga burners in Chinese restaurants but may have domestic applications as well. Traditional Chinese restaurant commercial cooking tables used for heating woks by gas burners during cooking of Chinese foods have table tops with a wok-supporting, annular-shaped trivet positioned over a hot combustion gas opening and with its surfaces in direct contact with flames and gases from the burners and heat generated from the gas burners radiates to the trivet and to the table top and the trivet then requires water cooling by using a continuously-running fresh water curtain. The warm cooling water exiting the table top then runs off but is unsuitable for recycling because the warm run-off water not only pollutes streams but is an environment which fosters growth of pathogenic bacteria and cannot be stored and recycled. It has been estimated that the volume of water used for cooling Chinese wok cooking tables is about 1.5 million litres annually. It is therefore an object of this invention to provide a convnection air flow cooling system for Chinese restaurant cooking table tops which eliminates for water cooling. The present invention according to a broad concept provides a method and means for providing convection air flow cooling for a Chinese restaurant cooking table tops and which eliminates the need for water cooling. The invention according to one aspect provides apparatus for convention air-cooling of a Chinese cooking table top as a replacement for a continuously-flowing water-cooling curtain and which comprises means for forming at least one convection air flow, trivet-cooling gap between at least one wok-supporting trivet and at least one opening surrounding and above a combustion chamber of at least one gas ring burner of the table, the means for forming the at least one convection air-flow trivet-cooling gap comprises at least one movable, vertically-adjustable, trivet support frame mounted within the table separately from a stationary support frame for the at least one gas ring burner, the at least one gas ring burner being used for heating a wok placed upon the table top and upon the at least one trivet above a respective gas burner combustion gas opening and wherein the apparatus further comprises at least one hollow, vertically and downwardly extending heat-shield between the at least one gas ring burner and the at least one trivet. In a preferred form of the invention the convection cooing air is delivered onto a trivet via slots incorporated into a cast wok ring trivet-support assembly and thence up up into an exhaust fan an canopy unit.

-2 in one form of the invention, there is aq single gas ring burner support frame and a single burner mounted upon the frame and a single, movable, vertically-adjustable, trivet-supporting frame with a single trivet supported by and removable from the trivet-supporting frame. In another form of the invention, there are a plurality of gas ring burner support frames each with a gas ring burner mounted thereon and a plurality of movable, vertically-adjustable, trivet support frames e ch with a single trivet supported by and removable from the trivet support frame. According to the invention, convention air-flow cooling air is delivered onto each trivet via slots incorporated into a casts wok ring ring trivet-support assembly for passage upward therethrough into an e haust fan and canopy unit. Some particular features of the invention of each trivet of the invention are that is stands above the top surface of the cooking table to a primary convention air-flow cooking gap and the table top has a convex annular, wok-supporting surface surrounding the opening atop the combustion chamber, e ch trivet has an unnular rimmed top with interrupted inner and rearwardly and radially-inwardly-facing bevelled upper sufaces which form primary convection air-flow cooling gaps whenever a wok is placed upon the trivet when the burner is operating and whenever a wok ring is installed is installed or placed upon th convex annular wok-supporting table top surface. Another feature of the trivet of the convection air-flow cooling apparatus of the invention is that it is detachable from the cooking table top.

-2 The table top convection cooling air-producing apparatus of the invention Includes at least one gas burner-supporting stationary frame fixed within a Chinese cooking table cabinet and at least one movable, vertically-adjustable trivet-supporting frame mounted within the cabinet, the trivet-supporting frame being separate from the gas burner support f frame and the cooling air is delivered onto a trivet via slots incorporated into a cast wok ring trivet-support assembly and thence up into an exhaust fan and canopy unit. In one form of the invention, there is a single gas ring burner support frame and a single burner mounted upon the frame and a single movable, vertically adjustable trivet supporting frame with a single trivet supported by and removable from the trivet-supporting VO frame. In- another form of the invention there are a plurality of gas ring burner support frames each with a gas ring burner mounted thereon and a plurality of movable, vertically adjustable trivet-support frames each with a single trivet supported by and removable from the trivet-support frame. t 5 According to the invention, convection air-flow cooling air is delivered onto each trivet via slots incorporated into a caste wok ring trivet-support assembly for passage upward into an exhaust fan and canopy unit. Some particular features of each trivet of the invention are that it stands above the top surface of the cooking table to form a primary convection air-flow cooling gap and the 9,o table top has a convex annular wok-supporting surface surrounding the opening atop the combustion chamber, each trivet has an annular rimmed top with interrupted inner and rearwardly and radially inwardly facing bevelled upper surfaces which form primary convection air-flow cooling gaps whenever a wok is placed upon the trivet when the burner is operating and whenever a wok ring is installed or placed upon the convex annular wok 2-5 supporting table top surface. Another feature of the trivet of the convection air flow cooling apparatus of the invention is that it is detachable from the cooking table top.

-3 A further feature of each trivet of the invention is that, when it is installed and in operation it is formed or provided with an integral, downwardly-directed, cylindrically-shaped heat shielding skirted portion depending therefrom and which forms an outer heat shield and combustion gas flow deflection and primary convection air-cooling air flow means Other subsidiary features of the invention are that each combustion chamber includes an additional or secondary heat deflecting and convection air air-flow cooling means formed by a metallic cylindrical inner sleeve which is adapted to be slidably and removably fitted inside a skirted portion of each respective trivet and this inner sleeve creates both a heat shield and a cooling air flow gap for secondary convection air-flow cooling within the 0 region surrounding the combustion zone of the gas ring burner within the cooking table cabinet and wherein the inner sleeve retards heating of internal surface of the skirted side wall of the trivet. Furthermore, there are additional advantageous features of the trivet in that the bottom edge of the skirted cylindrical portion thereof has four circumferentially-equispaced 6 slotted locating flanges projecting downwardly therefrom, all slotted flanges being mutually, circumferentially spaced at 90 degrees and trivet-mounting and trivet support means in the form of cross bars are mounted within the table cabinet which enable slidable insertion and removal of cylindrically-shaped, skirted heat-shielding inner sleeve members, respectively into and out of the circular combustion zone opening of the cooking table top and wherein the slot 2o of each trivet skirt flange forms a first member of a trivet-locating and height adjustment system whereby it is adapted to releasably engage with and be located on and be supported by the cross bars which are also mutually arranged at 90 degrees to correspond circumferentially with slots of the slotted locating flanges depending from the skirted portion of the trivet so that when in use and installed, the slots and vertically oriented edges of the £ flanges are mutually vertically in register or in further detail the cross bars have a vertically- -4 orientated main surface which is of complementary shape to the side surfaces of the slots of the slotted flanges of the trivet. Advantageous features of the invention are the inclusion of trivet-supporting cross bars which each have a vertically orientated main surface which have a vertically-orientate main surface which is of complementary shape to the slots of the trivet flanges, the bottom edge of each trivet or rather trivet-extension skirt) thus being provided with notches to enable positioning and correct location of it with respect to the table top and in association with the slot arrangement, the cross bars form a trivet supporting base and form the second of two co operating members of a trivet locating means with respect to the combustion opening of the table and are arranged as an integral but height-adjustable structure in the form of a cross the ends of which are suspended underneath the table (and below and clear of burner-mounting flanges by threaded bolt sets to enable adjustment of a convection cooling-air flow gap between each trivet and the table top. Additionally, each cross bar also supports the bottom edge of a second or inner slidably-removable cylindrical gap-forming sleeve. A non-limiting example of a practical arrangement of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a top perspective view of a wok-supporting Chinese restaurant cooking table with two gas burners and incorporating convection air-flow cooling means of the present invention. 20 Figure 2 is a central vertical section of the cooking table of Figure 1 which incorporates the air-flow cooling means of the invention. Figure 3 is a top plan view of a convection air flow cooling trivet member of the invention. Figure 4 is a vertical section taken along the line A-A of Figure 3. Figure 5 is a fragmentary partly diagrammatic view of convection airflow cooling through the Chinese cooking table of Figures 1 to 4 incorporating the invention.

-5 Referring to the drawings and first of all to Figure 1, there is shown a wok supporting Chinese cooking table wherein woks (not shown) are adapted to be placed upon wok-supporting table-top trivets and are each heated underneath by a gas ring burner and which, as shown in Figure 2 , has been modified by incorporating within the trivets convection air flow cooling members which replace conventional cooking table top cooling via continuously-running fresh water cooling. In more detail and referring to all the drawings 1 to 5, there is shown a waterless, Chinese (wok) cooking table which comprises a cabinet preferably preferably constructed of a MS angle-iron cabinet frame cladded with sheets of 304 -N4 x1.2mm stainless steel. There 10 is mounted upon the top surface 10a of the table 10 and above a respective gas burner which in this example is one of a pair of gas burners, a pair of wok-supporting circular apeetured trivets 11 and 11 which surround the wok-heating circular opening atop each combustion chamber which, as shown in Figure 2, has a respective gas burner 13 (left-hand side burner) and 14 (right-hand side burner - the left-hand side burner is a chimney burner with twenty rS four jets, the right-hand side burner is a duck bill burner of eighteen jets- a Mongolian chimney burner with twenty four Mongolian nozzle injectors may additionally or instead be used. Fluing of combustion gases from the combustion chamber of each burner is via slots incorporated into wok-supporting rings located within the cast wok ring assembly and thence into an exhaust fan canopy/fan unit. Each burner assembly has a standing pilot light for 2.o ignition to the burner assembly which also incorporates a flame failure cut-out. The burners are mounted upon respective horizontally-positioned angle-iron bars 13a and 14a as shown more clearly in the larger-scale drawing of Figure 5. Alternatively, a cooking table model which has only a single trivet and a single gas burner may be used. Or instead a table model having three or more trivets and three or more burners may be used. In this example 2 the two trivets 11 and 12 stand proud from the top surface of the table 10 to form a primary convection air-flow cooling gap. When the trivets 11 and 12 are installed or placed upon the convex annular wok-supporting table top surface 1 Oa of the cooking table top, interrupted rearwardly or radially inwardly-facing bevelled upper surfaces 11 a and 12a of -6 the annular rim of the trivets 11 and 12 form primary convection air-flow cooling gaps whenever a wok is placed upon it when the burners 13 and 14 are operating. As shown in all of Figures 1 to 5, the upper surface of the rim of each trivet tapers downwardly and the undersurface stands proud of the convex rim surrounding the hot gas exhaust outlet and the table top to create a primary convection cooling air-flow gap between the bottom of the trivet and the table top whereby each trivet is detachable from the cooking table top. Each trivet has a downwardly-directed cylindrical heat-shielding skirted portion 11 b and 12b respectively depending therefrom for each burner and each of which forms an outer heat shield and combustion gas flow deflection and primary convection cooling air flow means. Surrounding each burner there is also provided an additional or secondary heat-deflecting and convection air-flow cooling means which is formed by an internal cylindrical (and slidably removable) inner sleeve 15 and 16 respectively, which are each adapted to be slidably and removably fitted inside the skirted portion 11 b and 12b of a respective trivet 11 and 12. each sleeve 15 or 16 creates both a heat shield and a cooling air flow gap for secondary S convection air-flow cooling within the region surrounding the combustion zone of each respective gas ring burner within the cooking table - primary and secondary airflows are shown in Figure 5 which also shows direction of combustion air flow designed by the arrow labelled "H". The purpose of each sleeve 15 and 16 is to retard heating of the internal surface of the side wall or skirt of each trivet. Referring again to Figure 5, the bottom edge of the skirted portion of each trivet has four circumferentially-equispaced skirted locating flanges projecting downwardly therefrom, three being shown and labelled 17, 18 and 19 (for the left-hand side trivet) and 17a, 18a and 19a for the right-hand side trivet) all these slotted flanges are mutually spaced at 90 degrees. There is also shown trivet-mounting and support means in the form of cross bars three only of four being shown and are labelled 20, 21, and 22 respectively ( for the right-hand side trivet 11) and 20a, 21a and 22a for the left-hand side trivet 12 which enable slidable insertion and removal of cylindrically-shaped skited trivet portion and separate -7 sleeve member, respectively into and out of a circular opening in the table top above combustion regions of the table. The slot of each trivet skirt flange forms a first member of a trivet locating and trivet height adjustment system whereby it is adapted to releasably engage with and be located and be supported by a respective cross bar 20 or 21 or 22 which are each also mutually circumferentially arranged at 90 degrees with respect to each other to correspond circumferentially with the slots of the slotted locating flanges depending from the skirted portion of each trivet so that when in use and installed or in working position, the slots and vertically orientated edges of the flanges are mutually vertically in register or in further detail the cross bars have a vertically-orientated main surface which is of complementary shape to the inside surfaces of the four slots of the slotted flanges of the skirted portion of a respective trivet such as the three shown 17, 18 and 19 or 17a, 18a and 19a respectively. The four trivet-supporting cross bars ( three only being shown and labelled) 20, 21 and 22 respectively, each has a vertically-orientated main surface which is of complementary shape to the slots of the trivet flanges. Each trivet is provided with notches to enable positioning and correct location of it with respect to the table top. The cross bars form a trivet-supporting base and form a second of two co-operating members of a trivet locating means with respect to the combustion opening of the table top and are arranged as an integral but height-adjustable structure in the form of a cross the ends of which are suspended underneath the table top ( and below and clear of the burner-mounting flanges ao 13a, 14a) by four threaded bolt sets two of which are visible and are designated 23 and 24 (on the left hand side trivet shown in Figure 2 ) and replicated by 23a and 24a (for the right hand side trivet). To enable adjustment of a convection cooling air flow between each trivet and the opening surrounding the combustion gas chamber of the table top, in adition to enabling vertical or height adjustment of the skirted trivet , the trivet base supporting cross bar S' also supports the bottom edge of each slidably-removable inner and secondary convection air flow cooling gap-forming cylindrical sleeve 15 and 16 respectively for the left-hand burner combustion chamber arrangement and replicated as 15a and 16a for the right-hand side -8 burner arrangement. The cooking table assembly also includes a swivel laundry arm 25 mounted centrally above the wok ring and located on the splash back 26 of table top 10 and has a knee-operated water control for filling of wok bowls and for washing down purposes. A drainage channel is provided in the front of the unit and is recessed to prevent spillage from the wok cooking table top, A removable mesh strip is also preferably provided to mcatch large waste items before they enter and drainage system.

Claims (17)

1. Apparatus for convention air-cooling of a Chinese cooking table top as a replacement for a continuously-flowing water-cooling curtain and which comprises means for forming at least one convection air flow, trivet-cooling gap between at least one wok-supporting trivet and at least one opening surrounding and above a combustion chamber of at least one gas ring burner of the table, the means for forming the at least one convection air-flow trivet-cooling gap comprises at least one movable, vertically-adjustable, trivet-support frame mounted within the table separately from a stationary support frame for the at least one gas ring burner, the at least one gas ring burner being used for heating a wok placed upon the table top and upon the at least one trivet above a respective gas burner combustion gas opening and wherein the apparatus further comprises at least one hollow, vertically and downwardly-extending heat-shield between the at least one gas ring burner and the at least one trivet.

2. Apparatus according to claim 1 wherein there is a single gas ring burner support frame and a single burner mounted thereon and a single movable, vertically-adjustable, trivet-support frame and a single trivet supported by and removable from the trivet-support frame.

3. Apparatus according to claim 1 or 2 wherein there are a plurality of gas ring burner support frames each with a gas ring burner mounted thereon and a plurality of movable, vertically adjustable trivet-support frames each with a single trivet supported by and removable from its respective trivet-support frame.

4. Apparatus according to any preceding claim wherein convection air flow cooling air is delivered onto each trivet via slots incorporated into a cast wok r ing trivet=support assembly for passage upward into an exhaust canopy/fan unit.

5. Apparatus according to any preceding claim wherein each trivet stands proud of the top surface of the cooking table top to form a primary convection-cooling air flow gap.

6. Apparatus according to any preceding claim wherein the table top has a convex, annular wok-supporting surface surrounding the opening above the combustion chamber.

7. Apparatus according to any preceding claim wherein each trivet has an annular rimmed top with interrupted inner and rearwardly and radially-inwardly facing bevelled upper surfaces which form primary convection air flow cooling gaps whenever a wok is placed upon the trivet when the burner is operating.

8. Apparatus according to any preceding claim wherein the upper surface of the rim of each trivet tapers downwardly and the undersurface stands proud of the convex rim of the hot heating gas exhaust outlet and the table top to create a primary convection-cooling air-flow gap -10 between the bottom of the rivet and the cooking table top whereby each trivet is detachable from the cooking table top.

9. Apparatus according to any preceding claim wherein each trivet has a downwardly directed cylindrical heat-shielding skirted portion depending therefrom and which forms an outer heat shield and combustion gas flow deflection and primary convention air cooling air flow means.

10. Apparatus according to any preceding claim wherein each combustion chamber includes an additional or secondary heat deflecting and convection air flow cooling means formed by a cylindrical inner sleeve which is adapted to be slidably and removably fitted inside a skirted portion of each respective trivet.

11. Apparatus according to claim 10 wherein the inner sleeve creates both a heat shield and a cooling air flow gap for secondary convection air flow cooling within the region surrounding the combustion zone of the gas ring burner within the cooking table cabinet and wherein the inner sleeve retards heating of the internal surface of the side wall of the skirt of the trivet.

12. Apparatus according to any preceding claim wherein the bottom edage of the skirted portion of each trivet has four circumferentially-equispaced slotted locating flanges projecting downwardly therefrom, all slotted flanges being mutually circumferentially-spaced at 90 degrees and trivet mounting and trivet support means in the form of cross bars a re mounted within the table cabinet which enable slidable insertion and removal of cylindrically-shaped slirted, heat shielding inner sleeve members respectively into and out of the circular combustion zone opening in the cooking table top and wherein the slot of each trivet skirt flange forms a first member of a trivet locating and height adjustment system whereby it is adapted to releasably enegage with and be located on and be supported by the cross bars which are also mutually arranged at 90 degrees to correspond circumferentially with the slots of the slotted locating flanges depending from the skirted portion of the trivet so that when in use and installed, the slots and vertically-oriented edges of the flange are mutually vertically in register or in further detail the cross bars havbe a vertically oriented main surface which is of complementary shape to th side surfaces of the slots of the slotted flanges of the trivet.

13. Apparatus according to claim 12 wherein the trivet-supporting cross bars each have a vertically-orientated main surface which is of complementary shape to the slots of the trivet flanges, each trivet being provided with notches to enable positioning and correct location of it with respect to the table top. -11.

14. Apparatus according to claim 12 or 13 wherein the cross bars form a trivet-supporting base and form the second of two co-operating members of a trivet-locating means with respect to the combustion opening of the table and are arranged as an integral but height-adjustable structure in the form of a cross the ends of which are suspended underneath the table and below and clear of burner mounting flanges by threaded bolt sets to enable adjustment of a convection- cooling air flow gap between each trivet and the table top.

15. Apparatus according to any one of claims 14 to 16 wherein each cross bar also supports the bottom edge of a second or inner slidably-removable cylindrical, gap-forming sleeve.

16. Apparatus according to any preceding claim wherein a drainage channel with an outlet is provided at the rear of the table top and is recessed to prevent slippage from the table top.

17. Apparatus according to claim 16 wherein a removable mesh strip is also provided at the drainage channel outlet for removal of solid waste items. Dated this ( day of ' c 2015 COMMERCIAL FOOD MACHINERY OF VIC. PTY.LTD. By Our Patent Attorney John Loveluck-Davies of John L Davies & Co