CA1256480A - Space heating element comprising a ceramic shaped body provided with an electrically resistive coating bonded thereto - Google Patents
Space heating element comprising a ceramic shaped body provided with an electrically resistive coating bonded theretoInfo
- Publication number
- CA1256480A CA1256480A CA000475428A CA475428A CA1256480A CA 1256480 A CA1256480 A CA 1256480A CA 000475428 A CA000475428 A CA 000475428A CA 475428 A CA475428 A CA 475428A CA 1256480 A CA1256480 A CA 1256480A
- Authority
- CA
- Canada
- Prior art keywords
- electrically
- heating element
- layer
- electrically resistive
- space heating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
- H05B3/22—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible
- H05B3/26—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor mounted on insulating base
- H05B3/265—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor mounted on insulating base the insulating base being an inorganic material, e.g. ceramic
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Resistance Heating (AREA)
- Surface Heating Bodies (AREA)
- Central Heating Systems (AREA)
Abstract
ABSTRACT
The invention is concerned with the problem of providing a space heating element which supplies a high thermal yield while requiring little electrical power, and is also capable of being used as an element of design for the periphery of the room and may be installed in such a manner that no channels are formed which might force air currents to circulate in the room to be heated. The element comprises a shaped ceramic body, such as a tile, which is provided on the side facing away from the side visible from the space to be heated with a heating conductor extending across the surface in the form of an electrically resistive coating, comprising non-metallic particles having a large specific area, being electrically conductive and not substantially altering their electrical conductivity at higher temperatures, these particles being embedded in a carrier substance which is not, or only poorly, electrically conductive. This material is applied in such a way that the resistive coating exhibits even electrical and thermal conductivity, and may consist of an electrically resistive film which is stuck by adhesive to the face of the ceramic body comprising a polyester cover layer, a conductive intermediate layer as a resistive layer provided with supply lines and removal lines, and a polyester bottom layer. Such an element may be used as a heating element for lining swimming pools or as a heatable tile for walls, tables, ceilings or floors or as a radiator covering.
The invention is concerned with the problem of providing a space heating element which supplies a high thermal yield while requiring little electrical power, and is also capable of being used as an element of design for the periphery of the room and may be installed in such a manner that no channels are formed which might force air currents to circulate in the room to be heated. The element comprises a shaped ceramic body, such as a tile, which is provided on the side facing away from the side visible from the space to be heated with a heating conductor extending across the surface in the form of an electrically resistive coating, comprising non-metallic particles having a large specific area, being electrically conductive and not substantially altering their electrical conductivity at higher temperatures, these particles being embedded in a carrier substance which is not, or only poorly, electrically conductive. This material is applied in such a way that the resistive coating exhibits even electrical and thermal conductivity, and may consist of an electrically resistive film which is stuck by adhesive to the face of the ceramic body comprising a polyester cover layer, a conductive intermediate layer as a resistive layer provided with supply lines and removal lines, and a polyester bottom layer. Such an element may be used as a heating element for lining swimming pools or as a heatable tile for walls, tables, ceilings or floors or as a radiator covering.
Description
The present invention rela~es to a space heating element comprising a ceramic shaped body which is provided on the side facing away from the side visible from the space to be heated, with a heating conductor extending across its surface in the form of an electrically resistive coating.
Elements serving the purpose of space heating are generally provided in the form of ribbed or panel radiators below window openings so that the air of the room which hey heat rises above the window openings, thereby producing a curtain of wann air in front of the window opening. In the case of radiators set up against walls as well, there is a movement of air from the floor to the ceiling of the room being heated, whereby the heat radiated by the radiator into the room plays only a small part.
Conventional radiant elements proper which are provided in rooms have a radiating area which is very limited locally,and work at high temperatures.
The prior art further includes floor heating, by which heating coils containing a liquid heat transfer medium, or else electric heating conductors, are provided in the floor pavement or beneath the uppermost floor covering.
Floor heating is relatlvely troublesome and expensive to install, however, and requires relatively complicated control means.
There thus exists a need to form elements of design for the periphery of the room itself in such a way that they can perform singly, in groups or in the form of the en-,' ~
_ 2 tire Deriphery of ~he room or a substantial part t~ereof,~he functlon of heating the room or a part o~ the room periphery to be heated or kept warm.
¦ S Examples of such elements of design for the periphery of rooms are ceramic shaped bodies such as tiles, w~ich ac~
as floor or wall lining ~iles for designing ~he walls or the floor or ceiling of private rooms, stores and offices, but also of sanitary rooms, gymnasiums and indoor swim-ming pools. Such ceramic shaped bodies may also be shaped bricks for lining swimming pools, etc.
.. ..
A ~hlet issued by Canespa KG, 3005 Hemmingen-Westerfeld, Gutenbergstrasse 13, in 1975 already reveals a wireless heating system called "Canespa Therm" (trade mark), in which a heating varnish layer is provided as an electrically resistive coating on the back of shaped bodies, in fact of ceramic tiles. This heating varnish layer is covered by a polyurethane foam body. This system did not find wide acceptance, however, since there was repeatedly overheating locally, resulting in harmful complications which even led to danger for persons and objects.
The prior art also includes an electrical space heating device according to DE-A 14 40 971, comprising a carrier with a large smooth surface and a thin hea~ing conductor extending across ~his surface and adhering directly there-to. The earrier consists of an earthenware or vitreous fused silica tile. This tile is provided on its side facing away from the visible side with a thin, adhesive, imetallic heat conducting coating extending across the surface and formed by precipitating a chemical solution, or bears on this side an adhesive heat conducting coating consisting of a very thin aluminum layer.
~t is necessary in the case of such a space heating de-vice to provide spacing means between the tile and the ~ 3 --ca~ie~ fac:e which hears it, whlch ~n ~u~ o~
a take-up for ~he alr o~ the roam beh~d the ~pac2 heat-lng de~rice wit:h all the dlsadv~ntages descr~bed abo~7e whlch ha~re already been observed in the case o~ othe~
5 space heatir~g devices. Further;n~re, the metallic re-s~sti~re layers used have a relatively low resistance value and re~ e high electrical pow~r ko obtain a suf icient ther~aal yield .
10 DE-A 19 ~4 202 an~ the non prepublished DE-A 33 Z5 204 disclose a s~Leet-liX~ el ectrical heating ap~aratus haYing a sheet~ ce carrier which takes up a heating element, in whic~ the heating element is ~or~ed as a thin layer of elec~rically conductive material wh' ch 1; is applied to one surface of the carrie-. Even if the elec~_ically c~ncu~ti~e material consists wholly or partially of s~iconductor material, as described in DE-A 33 25 204, no success can be achleved therewith because the laye-s cannot ~e produce~ in a reproducible Z0 manner with r~s?ec~ to their elect~ical r~sistance when made of such material. The heating a?paratus therefore exhibit heatin~ ca?acities which diffe_ from piece to piece.
25 The invention is directed to the problem of providing a space heating element which supplies a high thermal yield while re~uiring little elec rical power, is capable of being used as an element of design for the periphery of the room and may be installed in such a manner that no channels are formed which ~ight force air currents to circulate in the room to be heated, but is also reproducible at will, i.e. exhibits the desired heating capacit~ from piece to piece.
- 3a -~
In accordance with the present invention there is provided a space heating elerr,ent comprising a ceramic shaped body which is provided on one side with an electrically resistive layer made of a material comprising non-metallic particles which have a large specific area, which are sufficiently electrically conductive, and which do not substantially alter their electrical conductivity at the higher temperatures of operation of the element, wherein the electrically resistive layer is provided on the side facing away from the visible side of the shaped ceramic body and that the particles are embedded in a carrier substance which is not electrically conductive, or is only poorly electrically conductive, so that the resistive layer exhibits uniform electrical and thermal conductivity.
Also in accordance with the invention there is provided an electrical space heating element comprising:
a ceramic tile body having a visible side and an opposite side which faces away from said visible side;
a polyester cover layer;
an adhesive bonding said polyester cover layer to said opposite side of said ceramic tile body;
a non-metallic electrically resistive layer disposed along the surface of said cover layer which faces away from said visible side of said ceramic tile body, said non-metallic electrically resistive layer being divided into at least two spatially separated areas, each of said spatially separated areas being separated from each other spatially separated area adjacent thereto by a separation space;
low resistance contacting means electrically contacting each of said at least two spatially separated areas in at least two different spatially separated locations; and a polyester bottom layer disposed over said cover layer and enclosing said electrically resistive layer therebetween, said bottom and said cover layers having a plurality of perforations provided therethrough along each of said separation spaces.
- 3b -Further in accordance with the invention there is provided an electrical space heatiny element coMprising:
a ceramic tile bo~y having a visible side which faces the space to be heated and an opposite side which faces away from the space to be heated;
an electrically resistive glaze applied to said opposite side, said electrically resistive glaze being embedded with non-metallic electrically conductive particles such that the electrieal resistance of said electrically resistive glaze is substantially constant as a function of its temperature; and low resistance contacting means for electrically contacting said electrically resistive glaze in at least two spatially separated areas.
Further in accordance with the invention there is provided an electrical space heating element comprising:
a ceramic tile body having a visible side which faces a space to be heated and an opposite side which faces away from the space to be heated;
an electrically resistive adhesive applied to said opposite side of said ceramic tile body, said electrically resistive adhesive having non-metallic electrically conductive particles embedded therein to give it a predetermined resistance value; and means for making electrical contact with said eleetrieally resistive adhesive along opposite ends of said eeramie tile body.
~ 4 w . .
The non-metallic particles whlch have a large speciflc area, are electrically conductive and do not substan tially alter their electrical conductivity at higher temperaturesO are preferably made of graphite and S carbon black, or mixtures thereof.
According to the present invention it is possible to provide a space heating element in the form of a radiant element a multiplicity of which may be used to cover an entire wall, ceiling or floor area, for example, the thermal radiation being even or divided up as desired. The heating can be achieved without significant circulation of the air in the room, and an even feeling of well-being can be achieved in the room at a substantially lower room temperature, which leads to a i5 considerable energy saving.
.
Since the heating elements are exactly reproducible with regard to their heating capacity, they can be - 20 produced in predetermined heating capacity classes.
Thus, any desired distribution of the thermal radiation from the lined surface is possible.
Any local faults in the electrically resistive coating have no material effect on the heating capacity. At most, there is a slight local reduction in the heating capacity, but no complete interruption thereof, and there is no local overheating.
The electrically resistive coating may consist of a layer made of non-ageing synthetic resin with an electrically conductive admixture such as an admixture of pure graphite, and have a construction such that the layer exhibits a resistance value which is necessary in accord-ance with the required electrical power. The resistancevalue may be set to values of a few Q up to several kn, B~3 which is effected by altering the percentage of the electrically conductive admixture of the resistive coating and/or altering the layer thickness. The layer thickness is usually between 10 and 50 ~.
In the case of a tile which is 100 cm x 100 cm, the the electrical power consumption is approx. 100 W, for example; in the case of a 60 x 60 tile it is approx. 30 W.
The term "non-ageing" refers in the case of the inven-tively selected layer to stability under continuous stress up to approx. 100C.
In an alternative embodiment of the invention, the electrically resistive coating consists of an electrical-ly resistive film comprising a polyester cover layer, a conductive intermediate layer provided with supply lines and removal lines, e.g. a graphite and/or carbon black layer,as a resistive layer, and a bottom layer of poly-ester. Such resistive films are known per se. Thesupply lines and removal lines leading to the resistive layer are generally designed in the form of copper bands.
However, the problem of using such resistive films in connection with the solution to the problem on which the invention is based is that polyester layers adhere poorly to the resistive layer so that it is not assured with sufficient certainty that the shaped body, e.g. a ceramic tile, provided on the side facing away from the visible side with such a resistive film, will adhere to the place of attachment, even if an adhesive is used which adheres, for example, to plastered walling and the back of the shaped body and to the polyester layers.
On the other hand, the use of polyester is recommended as the material for the cover and bottom layers, because polyester is very non-ageing. The problem which occurs when polyester material is used for the cover and bottom - lay~rs of the resistive film may be solved, howéver, l~
the resistive layex, in accordance with a modified em-bodiment of the invention, is divided up across its sur-face, leaving areas not covered thereby, the divided S areas communlcating with each other electrically and local perforations o~ the resistive film beiNg pro-vided in the areas not covered by the resistive layer.
An adhesive may be used for this purpose which sticks only to plastered surfaces ~nd ceramic surfaces, but not, or not well, to a polyester surface, bçcause the resistive film is perforated locally, e.g. punched through and attached to the side of the ceramic body facing away from the visible side thereof by means of the adhesive which is exposed in the perforated areas or pervades them at least partially. When a ceramic shaped body of such a design is stuck to a plastered layer, etc., by aid of a conventional adhesive as used for sticking ceramic shaped bodies to wall surfaces, etc., the adhesion takes place via the adhesive which is ex-posed in the perforatiohs or emerges therefrom, so that the ceramic shaped body is attached to the base intended to receive it in a manner which is only local but is suf-ficient if the perforation pattern is correctly dimensioned.
It is particularly advantageous to provide the electrically resistive coating ln the form of a resistive glaze. This glaze i5 applied to the shaped body after it is haked, and fixed by baking the shaped body once again. A glaze must be selected whose melting point is not higher than 750C.
Glazes with higher melting points have proved to be un suitable.
It is already disclosed in DE-A 19 24 202 to provide an electrically conductive glaze on the visible side of ceramic shaped bodies , but this glaze only serves the _ 7 _ purpose of removing static electricity, i.e. it is so highly resistive that it i5 not suitable for heating purposes.
A further possibility consists in designing the adhesive for fixing the ceramic shaped body to the carrier base, as an electrical resistor itself. It is then possible to use two different types of adhesive, the adhesive ad-jacent to the shaped body being made of electrically re-sistive material while the adhesive lying against thebase is an electrically insulating adhesive. The adhe-sives exhibit substantially the same thermal expansion properties and chemical compatibility, so that it is particularly simple to attach the electrically resistive ceramic shaped body in this manner.
The material for the electrically conductive resistive layex may be one which, when sub~ected to electric cur-rent, exhibits a temperature response such thatthe current absorption of the material decreases greatly as the tem-perature rises.
It is stated in DE-A 33 25 204 in connection with the use of semiconductors as a conductive material for a heating element, that semiconductors in particular ex-hibit a desirable negative temperature coefficient, but this is opposed by the statements in Rompp according to which the conductivity of semiconductors usually increases greatly as the temperature rises.
The contacting of the electrically resistive coating takes place expediently by means of contacting elements arranged symmetrically on the electrically resistive layer. Thus, the contacting elements may be arranged on square or rectangular tiles, for example, along two edges of the tile facing away from one another, in the form of con~ac~l~g band~ th~ tlle ls a c~r~mle ha~iAg a ~lie~ struc~ure on ~he bac~, ~he contack~ng ele~ent3 are exped~ently arranged i~ ~h~ cha~ lo cated at the edges ~acing away ~o~ each other betw~en 5 . th~ rldges limiting thes~ channels.
, It~ls possible sn the basis of:an embadiment the ~r.
~e~tion to finely adjus~ the resistance values o~ elec-tically resisti~e layers ln such space heating elements to desired values subs2~uently as well.
; This is effected ~n accordance with this ~mbodim~nt by reducing the layer t~ickness of khe resisti~e layer or heatins the resistive layer ln order to ~ncrease lts 15 resistance value.
~o increa3e the resistance value of the resistive layer, the layer thickness of the resistive layer can be reduced by sandblas'cing, electroerosion, brushing off, etc., or else the resistive layer i~
heated from the outside, for example by subjecting it to flames or radiation. It is also possible to conduct electric current of considerably yreater power than during normal operation through the resi-qtive layer. ~his alters the struc~ure of the resi~tive layer in such a wa~ that its resistance value is increased.
The invention will be bet~er understood with reference to the drawings in which:
Figure 1 is a rear view o~ a preferred embodiment o~ a space heating element according to the pre~ent invention in the form a tile having an electrically resistive layer and contacting elements;
Figure 2 is a cross-section of an al~ernative embodi~ent of a space heating element according to the present invention in the form o~ a tile having a relief structure on the back;
3 i9 a ~oe view of an embodiraent of a c~ra~c hea~ g elem~n ln the ~orm o~ a til~ and ha~ing an electrically re~istive ~llm applied thereto . Figure 4 i a partial sectlonal view of khe embodiment o~ the ceramic heating element 3hown in Fiyure 3, at an enlarged scale and Figure 5 is a cross-sec~ional view of a ~eramic tile with a resistive layer shown schema~ically to illu~ra~e a technique for changing the resistance o~ ~he resistive layer.
In Fig. 1 number 1 refers to a space heating ele~nt in general, here in the for~ of a tile, an ~lectrically resis~ive layer being located on its bacX 2. Numbers 3 and 4 re~
fer to contacting elements which are stuck ~o the elec-trically resistive layer or attached thereto in another manner. Numbers S and 6 re~er to the current supply lines.
Fig. 2 shows a cross-section of a space heating element which exists here in the form of a tile with a relief structure on the back 21. This back 21 exhibi~s ridges 22 and grooves 23. On the back o~ this tile, i.el on the side on which the ridges and grooves a~e located, an electrically conductive adhesive 24 is provided, for exa~ple. A conductor 27 is provided in a groove 26 adjacent to edge 25 of the tile. Adhesive 24 is of course an electrically resistive adhesive, l.e. a material which is conducti~re but conducts so poorly that the electrical energy conducted thereinto ls converted into thermal enersy.
In Fig. 3 number 31 refers to a ~e heating el~t in gen~x~, which, as shown in Fig. 4, exhibits a tile 41, an ad-hesi~e layer 42 and a resistive film 43. ~he resistive filn consists o~ a polyester cover layer 46 con~ected ~ -- 10 --- via adhesive layer 42 to the side 45 facing away from the visible slde 44 of tile 41, further of graphite and/or carbon black intermediate layers 43a, 43b, 43c as re-sistive layers each provided at the edge with supply lines and removal lines in the fc rm of copper bands 32 to 37 with current supply lines 38 (Fig. 3), and fi-nally of a polyester bottom layer 48 which is stuck to the supporting surface 49, e.g. plastered walling, via an adhesive layer 50. Resistive film 43 contains three webs 43a, 43b, 43c of resistive layer material in the embodiment shown, but may of course also have a greater structure.
Between webs 43a and 43b, and 43b and 43c there are areas 51 and 52 (Fig. 3) in which no resisti~e layer material is present. However, web 43a borders on area 51 via conduction band 36. Similarly, web 43c borders on area 52 via conduction band 33 while web 43b borders on each side on areas 51 and 52 via conduction bands 34 and 35. In areas 51 and 52, in which layers 46 and 48 are superjacent, there are perforations 53 through which the adhesive extends out of the layer and communi-cates with the adhesive from layer 50 on supporting sur-face 49. The individual conduction bands may be intercon-nected in any manner one chooses. The single tile 31 may also be replaced by three subtiles each assigned accordingly to webs 43a, 43b and 43c.
The possible design of the conductive intermediate layer or resistive layer in a form in which its area is divided up leaving areas not covered thereby, may involve, for example, a meander-shaped arrangement of the resistive layer or a division there-of into several sublayers in the form of bands, surface elements, etc., which extend across the surface but are electrically connected to each other or are to be con-nected to each other subsequently. The seleetion of the eorresponding pattern depends on the local data and/or the teehnical requirements.
In Fig. 5 number 91 indicates a ceramic tile on which a resistive layer 92 is provided. The thickness in whieh this resistive coating 92 is applied is reduced using a suitable means, e.g. sandblasting, electro-erosion, brushing off, etc. In the embodiment shown this is effected using a brush 93 which rotates, for example, so that the thickness of application is re-dueed to the desired thickness as indicated in area 94. This also reduces the conductivity of this layer, i.e. the surfaee resistance inereases. In this manner fine adjustment of the resistance value of layer 92 is possible.
Elements serving the purpose of space heating are generally provided in the form of ribbed or panel radiators below window openings so that the air of the room which hey heat rises above the window openings, thereby producing a curtain of wann air in front of the window opening. In the case of radiators set up against walls as well, there is a movement of air from the floor to the ceiling of the room being heated, whereby the heat radiated by the radiator into the room plays only a small part.
Conventional radiant elements proper which are provided in rooms have a radiating area which is very limited locally,and work at high temperatures.
The prior art further includes floor heating, by which heating coils containing a liquid heat transfer medium, or else electric heating conductors, are provided in the floor pavement or beneath the uppermost floor covering.
Floor heating is relatlvely troublesome and expensive to install, however, and requires relatively complicated control means.
There thus exists a need to form elements of design for the periphery of the room itself in such a way that they can perform singly, in groups or in the form of the en-,' ~
_ 2 tire Deriphery of ~he room or a substantial part t~ereof,~he functlon of heating the room or a part o~ the room periphery to be heated or kept warm.
¦ S Examples of such elements of design for the periphery of rooms are ceramic shaped bodies such as tiles, w~ich ac~
as floor or wall lining ~iles for designing ~he walls or the floor or ceiling of private rooms, stores and offices, but also of sanitary rooms, gymnasiums and indoor swim-ming pools. Such ceramic shaped bodies may also be shaped bricks for lining swimming pools, etc.
.. ..
A ~hlet issued by Canespa KG, 3005 Hemmingen-Westerfeld, Gutenbergstrasse 13, in 1975 already reveals a wireless heating system called "Canespa Therm" (trade mark), in which a heating varnish layer is provided as an electrically resistive coating on the back of shaped bodies, in fact of ceramic tiles. This heating varnish layer is covered by a polyurethane foam body. This system did not find wide acceptance, however, since there was repeatedly overheating locally, resulting in harmful complications which even led to danger for persons and objects.
The prior art also includes an electrical space heating device according to DE-A 14 40 971, comprising a carrier with a large smooth surface and a thin hea~ing conductor extending across ~his surface and adhering directly there-to. The earrier consists of an earthenware or vitreous fused silica tile. This tile is provided on its side facing away from the visible side with a thin, adhesive, imetallic heat conducting coating extending across the surface and formed by precipitating a chemical solution, or bears on this side an adhesive heat conducting coating consisting of a very thin aluminum layer.
~t is necessary in the case of such a space heating de-vice to provide spacing means between the tile and the ~ 3 --ca~ie~ fac:e which hears it, whlch ~n ~u~ o~
a take-up for ~he alr o~ the roam beh~d the ~pac2 heat-lng de~rice wit:h all the dlsadv~ntages descr~bed abo~7e whlch ha~re already been observed in the case o~ othe~
5 space heatir~g devices. Further;n~re, the metallic re-s~sti~re layers used have a relatively low resistance value and re~ e high electrical pow~r ko obtain a suf icient ther~aal yield .
10 DE-A 19 ~4 202 an~ the non prepublished DE-A 33 Z5 204 disclose a s~Leet-liX~ el ectrical heating ap~aratus haYing a sheet~ ce carrier which takes up a heating element, in whic~ the heating element is ~or~ed as a thin layer of elec~rically conductive material wh' ch 1; is applied to one surface of the carrie-. Even if the elec~_ically c~ncu~ti~e material consists wholly or partially of s~iconductor material, as described in DE-A 33 25 204, no success can be achleved therewith because the laye-s cannot ~e produce~ in a reproducible Z0 manner with r~s?ec~ to their elect~ical r~sistance when made of such material. The heating a?paratus therefore exhibit heatin~ ca?acities which diffe_ from piece to piece.
25 The invention is directed to the problem of providing a space heating element which supplies a high thermal yield while re~uiring little elec rical power, is capable of being used as an element of design for the periphery of the room and may be installed in such a manner that no channels are formed which ~ight force air currents to circulate in the room to be heated, but is also reproducible at will, i.e. exhibits the desired heating capacit~ from piece to piece.
- 3a -~
In accordance with the present invention there is provided a space heating elerr,ent comprising a ceramic shaped body which is provided on one side with an electrically resistive layer made of a material comprising non-metallic particles which have a large specific area, which are sufficiently electrically conductive, and which do not substantially alter their electrical conductivity at the higher temperatures of operation of the element, wherein the electrically resistive layer is provided on the side facing away from the visible side of the shaped ceramic body and that the particles are embedded in a carrier substance which is not electrically conductive, or is only poorly electrically conductive, so that the resistive layer exhibits uniform electrical and thermal conductivity.
Also in accordance with the invention there is provided an electrical space heating element comprising:
a ceramic tile body having a visible side and an opposite side which faces away from said visible side;
a polyester cover layer;
an adhesive bonding said polyester cover layer to said opposite side of said ceramic tile body;
a non-metallic electrically resistive layer disposed along the surface of said cover layer which faces away from said visible side of said ceramic tile body, said non-metallic electrically resistive layer being divided into at least two spatially separated areas, each of said spatially separated areas being separated from each other spatially separated area adjacent thereto by a separation space;
low resistance contacting means electrically contacting each of said at least two spatially separated areas in at least two different spatially separated locations; and a polyester bottom layer disposed over said cover layer and enclosing said electrically resistive layer therebetween, said bottom and said cover layers having a plurality of perforations provided therethrough along each of said separation spaces.
- 3b -Further in accordance with the invention there is provided an electrical space heatiny element coMprising:
a ceramic tile bo~y having a visible side which faces the space to be heated and an opposite side which faces away from the space to be heated;
an electrically resistive glaze applied to said opposite side, said electrically resistive glaze being embedded with non-metallic electrically conductive particles such that the electrieal resistance of said electrically resistive glaze is substantially constant as a function of its temperature; and low resistance contacting means for electrically contacting said electrically resistive glaze in at least two spatially separated areas.
Further in accordance with the invention there is provided an electrical space heating element comprising:
a ceramic tile body having a visible side which faces a space to be heated and an opposite side which faces away from the space to be heated;
an electrically resistive adhesive applied to said opposite side of said ceramic tile body, said electrically resistive adhesive having non-metallic electrically conductive particles embedded therein to give it a predetermined resistance value; and means for making electrical contact with said eleetrieally resistive adhesive along opposite ends of said eeramie tile body.
~ 4 w . .
The non-metallic particles whlch have a large speciflc area, are electrically conductive and do not substan tially alter their electrical conductivity at higher temperaturesO are preferably made of graphite and S carbon black, or mixtures thereof.
According to the present invention it is possible to provide a space heating element in the form of a radiant element a multiplicity of which may be used to cover an entire wall, ceiling or floor area, for example, the thermal radiation being even or divided up as desired. The heating can be achieved without significant circulation of the air in the room, and an even feeling of well-being can be achieved in the room at a substantially lower room temperature, which leads to a i5 considerable energy saving.
.
Since the heating elements are exactly reproducible with regard to their heating capacity, they can be - 20 produced in predetermined heating capacity classes.
Thus, any desired distribution of the thermal radiation from the lined surface is possible.
Any local faults in the electrically resistive coating have no material effect on the heating capacity. At most, there is a slight local reduction in the heating capacity, but no complete interruption thereof, and there is no local overheating.
The electrically resistive coating may consist of a layer made of non-ageing synthetic resin with an electrically conductive admixture such as an admixture of pure graphite, and have a construction such that the layer exhibits a resistance value which is necessary in accord-ance with the required electrical power. The resistancevalue may be set to values of a few Q up to several kn, B~3 which is effected by altering the percentage of the electrically conductive admixture of the resistive coating and/or altering the layer thickness. The layer thickness is usually between 10 and 50 ~.
In the case of a tile which is 100 cm x 100 cm, the the electrical power consumption is approx. 100 W, for example; in the case of a 60 x 60 tile it is approx. 30 W.
The term "non-ageing" refers in the case of the inven-tively selected layer to stability under continuous stress up to approx. 100C.
In an alternative embodiment of the invention, the electrically resistive coating consists of an electrical-ly resistive film comprising a polyester cover layer, a conductive intermediate layer provided with supply lines and removal lines, e.g. a graphite and/or carbon black layer,as a resistive layer, and a bottom layer of poly-ester. Such resistive films are known per se. Thesupply lines and removal lines leading to the resistive layer are generally designed in the form of copper bands.
However, the problem of using such resistive films in connection with the solution to the problem on which the invention is based is that polyester layers adhere poorly to the resistive layer so that it is not assured with sufficient certainty that the shaped body, e.g. a ceramic tile, provided on the side facing away from the visible side with such a resistive film, will adhere to the place of attachment, even if an adhesive is used which adheres, for example, to plastered walling and the back of the shaped body and to the polyester layers.
On the other hand, the use of polyester is recommended as the material for the cover and bottom layers, because polyester is very non-ageing. The problem which occurs when polyester material is used for the cover and bottom - lay~rs of the resistive film may be solved, howéver, l~
the resistive layex, in accordance with a modified em-bodiment of the invention, is divided up across its sur-face, leaving areas not covered thereby, the divided S areas communlcating with each other electrically and local perforations o~ the resistive film beiNg pro-vided in the areas not covered by the resistive layer.
An adhesive may be used for this purpose which sticks only to plastered surfaces ~nd ceramic surfaces, but not, or not well, to a polyester surface, bçcause the resistive film is perforated locally, e.g. punched through and attached to the side of the ceramic body facing away from the visible side thereof by means of the adhesive which is exposed in the perforated areas or pervades them at least partially. When a ceramic shaped body of such a design is stuck to a plastered layer, etc., by aid of a conventional adhesive as used for sticking ceramic shaped bodies to wall surfaces, etc., the adhesion takes place via the adhesive which is ex-posed in the perforatiohs or emerges therefrom, so that the ceramic shaped body is attached to the base intended to receive it in a manner which is only local but is suf-ficient if the perforation pattern is correctly dimensioned.
It is particularly advantageous to provide the electrically resistive coating ln the form of a resistive glaze. This glaze i5 applied to the shaped body after it is haked, and fixed by baking the shaped body once again. A glaze must be selected whose melting point is not higher than 750C.
Glazes with higher melting points have proved to be un suitable.
It is already disclosed in DE-A 19 24 202 to provide an electrically conductive glaze on the visible side of ceramic shaped bodies , but this glaze only serves the _ 7 _ purpose of removing static electricity, i.e. it is so highly resistive that it i5 not suitable for heating purposes.
A further possibility consists in designing the adhesive for fixing the ceramic shaped body to the carrier base, as an electrical resistor itself. It is then possible to use two different types of adhesive, the adhesive ad-jacent to the shaped body being made of electrically re-sistive material while the adhesive lying against thebase is an electrically insulating adhesive. The adhe-sives exhibit substantially the same thermal expansion properties and chemical compatibility, so that it is particularly simple to attach the electrically resistive ceramic shaped body in this manner.
The material for the electrically conductive resistive layex may be one which, when sub~ected to electric cur-rent, exhibits a temperature response such thatthe current absorption of the material decreases greatly as the tem-perature rises.
It is stated in DE-A 33 25 204 in connection with the use of semiconductors as a conductive material for a heating element, that semiconductors in particular ex-hibit a desirable negative temperature coefficient, but this is opposed by the statements in Rompp according to which the conductivity of semiconductors usually increases greatly as the temperature rises.
The contacting of the electrically resistive coating takes place expediently by means of contacting elements arranged symmetrically on the electrically resistive layer. Thus, the contacting elements may be arranged on square or rectangular tiles, for example, along two edges of the tile facing away from one another, in the form of con~ac~l~g band~ th~ tlle ls a c~r~mle ha~iAg a ~lie~ struc~ure on ~he bac~, ~he contack~ng ele~ent3 are exped~ently arranged i~ ~h~ cha~ lo cated at the edges ~acing away ~o~ each other betw~en 5 . th~ rldges limiting thes~ channels.
, It~ls possible sn the basis of:an embadiment the ~r.
~e~tion to finely adjus~ the resistance values o~ elec-tically resisti~e layers ln such space heating elements to desired values subs2~uently as well.
; This is effected ~n accordance with this ~mbodim~nt by reducing the layer t~ickness of khe resisti~e layer or heatins the resistive layer ln order to ~ncrease lts 15 resistance value.
~o increa3e the resistance value of the resistive layer, the layer thickness of the resistive layer can be reduced by sandblas'cing, electroerosion, brushing off, etc., or else the resistive layer i~
heated from the outside, for example by subjecting it to flames or radiation. It is also possible to conduct electric current of considerably yreater power than during normal operation through the resi-qtive layer. ~his alters the struc~ure of the resi~tive layer in such a wa~ that its resistance value is increased.
The invention will be bet~er understood with reference to the drawings in which:
Figure 1 is a rear view o~ a preferred embodiment o~ a space heating element according to the pre~ent invention in the form a tile having an electrically resistive layer and contacting elements;
Figure 2 is a cross-section of an al~ernative embodi~ent of a space heating element according to the present invention in the form o~ a tile having a relief structure on the back;
3 i9 a ~oe view of an embodiraent of a c~ra~c hea~ g elem~n ln the ~orm o~ a til~ and ha~ing an electrically re~istive ~llm applied thereto . Figure 4 i a partial sectlonal view of khe embodiment o~ the ceramic heating element 3hown in Fiyure 3, at an enlarged scale and Figure 5 is a cross-sec~ional view of a ~eramic tile with a resistive layer shown schema~ically to illu~ra~e a technique for changing the resistance o~ ~he resistive layer.
In Fig. 1 number 1 refers to a space heating ele~nt in general, here in the for~ of a tile, an ~lectrically resis~ive layer being located on its bacX 2. Numbers 3 and 4 re~
fer to contacting elements which are stuck ~o the elec-trically resistive layer or attached thereto in another manner. Numbers S and 6 re~er to the current supply lines.
Fig. 2 shows a cross-section of a space heating element which exists here in the form of a tile with a relief structure on the back 21. This back 21 exhibi~s ridges 22 and grooves 23. On the back o~ this tile, i.el on the side on which the ridges and grooves a~e located, an electrically conductive adhesive 24 is provided, for exa~ple. A conductor 27 is provided in a groove 26 adjacent to edge 25 of the tile. Adhesive 24 is of course an electrically resistive adhesive, l.e. a material which is conducti~re but conducts so poorly that the electrical energy conducted thereinto ls converted into thermal enersy.
In Fig. 3 number 31 refers to a ~e heating el~t in gen~x~, which, as shown in Fig. 4, exhibits a tile 41, an ad-hesi~e layer 42 and a resistive film 43. ~he resistive filn consists o~ a polyester cover layer 46 con~ected ~ -- 10 --- via adhesive layer 42 to the side 45 facing away from the visible slde 44 of tile 41, further of graphite and/or carbon black intermediate layers 43a, 43b, 43c as re-sistive layers each provided at the edge with supply lines and removal lines in the fc rm of copper bands 32 to 37 with current supply lines 38 (Fig. 3), and fi-nally of a polyester bottom layer 48 which is stuck to the supporting surface 49, e.g. plastered walling, via an adhesive layer 50. Resistive film 43 contains three webs 43a, 43b, 43c of resistive layer material in the embodiment shown, but may of course also have a greater structure.
Between webs 43a and 43b, and 43b and 43c there are areas 51 and 52 (Fig. 3) in which no resisti~e layer material is present. However, web 43a borders on area 51 via conduction band 36. Similarly, web 43c borders on area 52 via conduction band 33 while web 43b borders on each side on areas 51 and 52 via conduction bands 34 and 35. In areas 51 and 52, in which layers 46 and 48 are superjacent, there are perforations 53 through which the adhesive extends out of the layer and communi-cates with the adhesive from layer 50 on supporting sur-face 49. The individual conduction bands may be intercon-nected in any manner one chooses. The single tile 31 may also be replaced by three subtiles each assigned accordingly to webs 43a, 43b and 43c.
The possible design of the conductive intermediate layer or resistive layer in a form in which its area is divided up leaving areas not covered thereby, may involve, for example, a meander-shaped arrangement of the resistive layer or a division there-of into several sublayers in the form of bands, surface elements, etc., which extend across the surface but are electrically connected to each other or are to be con-nected to each other subsequently. The seleetion of the eorresponding pattern depends on the local data and/or the teehnical requirements.
In Fig. 5 number 91 indicates a ceramic tile on which a resistive layer 92 is provided. The thickness in whieh this resistive coating 92 is applied is reduced using a suitable means, e.g. sandblasting, electro-erosion, brushing off, etc. In the embodiment shown this is effected using a brush 93 which rotates, for example, so that the thickness of application is re-dueed to the desired thickness as indicated in area 94. This also reduces the conductivity of this layer, i.e. the surfaee resistance inereases. In this manner fine adjustment of the resistance value of layer 92 is possible.
Claims (19)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A space heating element comprising a ceramic shaped body which is provided on one side with an electrically resistive layer made of a material comprising non-metallic particles which have a large specific area, which are sufficiently electrically conductive, and which do not substantially alter their electrical conductivity at the higher temperatures of operation of the element, wherein the electrically resistive layer is provided on the side facing away from the visible side of the shaped ceramic body and that the particles are embedded in a carrier substance which is not electrically conductive, or is only poorly electrically conductive, so that the resistive layer exhibits uniform electrical and thermal conductivity.
2. A space heating element as claimed in claim 1, wherein the non-metallic particles are selected from graphite and carbon black.
3. A space heating element as claimed in claim 1, wherein the electrically resistive layer consists of an electrically resistive film which is stuck to the side of the ceramic shaped body facing away from the visible side thereof, which film comprises a polyester cover layer, an intermediate resistive layer provided with electric power supply lines, and a polyester bottom layer, the resistive film being attached to the side of the ceramic shaped body facing away from the visible side thereof by an adhesive which sticks both to a ceramic surface and to a polyester surface.
4. A space heating element as claimed in claim 2, wherein the electrically resistive layer consists of an electrically resistive film which is stuck to the side of the ceramic shaped body facing away from the visible side thereof, which film comprises a polyester cover layer, an intermediate resistive layer provided with electric power supply lines, and a polyester bottom layer, the resistive film being attached to the side of the ceramic shaped body facing away from the visible side thereof by an adhesive which sticks both to a ceramic surface and to a polyester surface.
5. A space heating element as claimed in claim 3, wherein the area of the intermediate resistive layer is divided up within the resistive film leaving areas not covered thereby, the divided areas communicating electrically with each other, and local perforations of the resistive film being provided in the areas not covered by the intermediate resistive layer.
6. A space heating element as claimed in claim 1, wherein the electrically resistive layer comprises an electrically resistive glaze whose melting point is not higher than 750°
Celsius.
Celsius.
7. A space heating element as claimed in claim 1, wherein the electrically resistive coating comprises an electrically resistive adhesive.
8. A space heating element as claimed in claim 7, wherein the electrically resistive adhesive is covered by an electrically insulating adhesive.
9. A space heating element as claimed in any one of claims 1 to 3, wherein the electrically resistive layer is provided with conductive contacting elements, the conductive contacting elements substantially consisting of the basic material of the resistive layer in which particles with higher electrical conductivity are provided, or in which a higher concentration of the conductive particles present are embedded, in order to increase the electrical conductivity.
10. A space heating element as claimed in any one of claims 1 to 3, wherein the distribution of the conductive particles in the resistive layer is such that there are provided local areas of denser distribution.
11. An electrical space heating element comprising:
a ceramic tile body having a visible side and an opposite side which faces away from said visible side;
a polyester cover layer;
an adhesive bonding said polyester cover layer to said opposite side of said ceramic tile body;
a non-metallic electrically resistive layer disposed along the surface of said cover layer which faces away from said visible side of said ceramic tile body, said non-metallic electrically resistive layer being divided into at least two spatially separated areas, each of said spatially separated areas being separated from each other spatially separated area adjacent thereto by a separation space;
low resistance contacting means electrically contacting each of said at least two spatially separated areas in at least two different spatially separated locations; and a polyester bottom layer disposed over said cover layer and enclosing said electrically resistive layer therebetween, said bottom and said cover layers having a plurality of perforations provided therethrough along each of said separation spaces.
a ceramic tile body having a visible side and an opposite side which faces away from said visible side;
a polyester cover layer;
an adhesive bonding said polyester cover layer to said opposite side of said ceramic tile body;
a non-metallic electrically resistive layer disposed along the surface of said cover layer which faces away from said visible side of said ceramic tile body, said non-metallic electrically resistive layer being divided into at least two spatially separated areas, each of said spatially separated areas being separated from each other spatially separated area adjacent thereto by a separation space;
low resistance contacting means electrically contacting each of said at least two spatially separated areas in at least two different spatially separated locations; and a polyester bottom layer disposed over said cover layer and enclosing said electrically resistive layer therebetween, said bottom and said cover layers having a plurality of perforations provided therethrough along each of said separation spaces.
12. The space heating element of Claim 11 wherein the resistance of said electrically resistive layer is substantially constant as a function of temperature.
13. The space heating element of Claim 12 wherein the material of said electrically resistive layer is selected from the group consisting of graphite and carbon black.
14. An electrical space heating element comprising:
a ceramic tile body having a visible side which faces the space to be heated and an opposite side which faces away from the space to be heated;
an electrically resistive glaze applied to said opposite side, said electrically resistive glaze being embedded with non-metallic electrically conductive particles such that the electrical resistance of said electrically resistive glaze is substantially constant as a function of its temperature; and low resistance contacting means for electrically contacting said electrically resistive glaze in at least two spatially separated areas.
a ceramic tile body having a visible side which faces the space to be heated and an opposite side which faces away from the space to be heated;
an electrically resistive glaze applied to said opposite side, said electrically resistive glaze being embedded with non-metallic electrically conductive particles such that the electrical resistance of said electrically resistive glaze is substantially constant as a function of its temperature; and low resistance contacting means for electrically contacting said electrically resistive glaze in at least two spatially separated areas.
15. The space heating element of Claim 14 wherein said electrically resistive glaze is applied to the ceramic tile body in the form of at least one rectangle and wherein said low resistance contacting means is a pair of copper bands disposed along two opposing edges of said at least one rectangle.
16. The space heating element of Claim 14 wherein the material of said non-metallic electrically conductive particles is selected from the group comprising graphite and carbon black.
17. The space heating element of Claim 14 wherein said electrically resistive glaze has a melting point not greater than 750°C.
18. An electrical space heating element comprising:
a ceramic tile body having a visible side which faces a space to be heated and an opposite side which faces away from the space to be heated;
an electrically resistive adhesive applied to said opposite side of said ceramic tile body, said electrically resistive adhesive having non-metallic electrically conductive particles embedded therein to give it a predetermined resistance value; and means for making electrical contact with said electrically resistive adhesive along opposite ends of said ceramic tile body.
a ceramic tile body having a visible side which faces a space to be heated and an opposite side which faces away from the space to be heated;
an electrically resistive adhesive applied to said opposite side of said ceramic tile body, said electrically resistive adhesive having non-metallic electrically conductive particles embedded therein to give it a predetermined resistance value; and means for making electrical contact with said electrically resistive adhesive along opposite ends of said ceramic tile body.
19. The space heating element of Claim 18 wherein the material of said non-metallic electrically conductive particles is selected from the group consisting of graphite and carbon black.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3407444.9 | 1984-02-29 | ||
| DE3407444 | 1984-02-29 | ||
| DEP3433667.2 | 1984-09-13 | ||
| DE19843433667 DE3433667A1 (en) | 1984-02-29 | 1984-09-13 | Ceramic moulding with electrical resistance coating bonded to back - with uniform electrical and thermal conductivity, useful for heating room, swimming pool etc. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1256480A true CA1256480A (en) | 1989-06-27 |
Family
ID=25818952
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000475428A Expired CA1256480A (en) | 1984-02-29 | 1985-02-28 | Space heating element comprising a ceramic shaped body provided with an electrically resistive coating bonded thereto |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0158091B1 (en) |
| JP (1) | JPS60258891A (en) |
| CA (1) | CA1256480A (en) |
| DK (1) | DK162004C (en) |
| FI (1) | FI83582C (en) |
| NO (1) | NO850814L (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU603082B2 (en) * | 1986-02-03 | 1990-11-08 | Buchtal Gesellschaft Mit Beschrankter Haftung | A covering for wall, ceiling or floor linings |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU1436597A (en) * | 1995-10-17 | 1997-05-07 | Magnus Kluge | Electrical resistance heating for air conditioning in dwellings and buildings |
| IT1396655B1 (en) * | 2009-02-13 | 2012-12-14 | Montanari | FLOOR CELL HEATING SYSTEM. |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5120043Y2 (en) * | 1971-06-30 | 1976-05-26 | ||
| DE2151626B2 (en) * | 1971-10-16 | 1975-10-23 | Reuter Maschinen- Und Werkzeugbau Gmbh, 2844 Lemfoerde | Process for the production of a rigid surface heating element which can be heated by electricity |
| CA1014429A (en) * | 1972-12-20 | 1977-07-26 | Seinosuke Horiki | Calorific device |
| JPS5034768A (en) * | 1973-08-01 | 1975-04-03 | ||
| US3878362A (en) * | 1974-02-15 | 1975-04-15 | Du Pont | Electric heater having laminated structure |
| DE2535622A1 (en) * | 1975-08-09 | 1977-02-17 | Terracom Ets | Flat surface electrical heating element - consisting of aggregate of conducting particles held between insulating layers |
| JPS5353954U (en) * | 1976-10-08 | 1978-05-09 | ||
| JPS5543751A (en) * | 1978-09-21 | 1980-03-27 | Tokyo Shibaura Electric Co | Plane heating element |
| JPS5568078A (en) * | 1978-11-16 | 1980-05-22 | Nippon Soken | Heating element |
| FR2490056A1 (en) * | 1980-09-05 | 1982-03-12 | Bonato Mario | Electrically powered heating panel - uses medium resistivity material on heat and electrically insulating base with electric insulator covering to provide uniform heat |
| JPS57113576A (en) * | 1980-12-30 | 1982-07-15 | Matsushita Electric Works Ltd | Panel heater |
| DE3311051A1 (en) * | 1983-03-25 | 1984-09-27 | Siemens AG, 1000 Berlin und 8000 München | TAPE FLEXIBLE HEATING ELEMENT CONSTRUCTED FROM ELECTRICALLY CONDUCTIVE PORCELAIN FROM PTC MATERIAL AND AN ORGANIC INSULATING PLASTIC AS BINDING AGENT, AND METHOD FOR PRODUCING THE FLEXIBLE HEATING ELEMENT |
-
1985
- 1985-02-28 EP EP19850102230 patent/EP0158091B1/en not_active Expired
- 1985-02-28 NO NO850814A patent/NO850814L/en unknown
- 1985-02-28 CA CA000475428A patent/CA1256480A/en not_active Expired
- 1985-02-28 DK DK93785A patent/DK162004C/en not_active IP Right Cessation
- 1985-02-28 JP JP4026985A patent/JPS60258891A/en active Pending
- 1985-02-28 FI FI850821A patent/FI83582C/en not_active IP Right Cessation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU603082B2 (en) * | 1986-02-03 | 1990-11-08 | Buchtal Gesellschaft Mit Beschrankter Haftung | A covering for wall, ceiling or floor linings |
Also Published As
| Publication number | Publication date |
|---|---|
| FI83582C (en) | 1991-07-25 |
| DK162004B (en) | 1991-09-02 |
| FI850821L (en) | 1985-08-30 |
| DK93785A (en) | 1985-08-30 |
| DK93785D0 (en) | 1985-02-28 |
| DK162004C (en) | 1992-02-10 |
| JPS60258891A (en) | 1985-12-20 |
| EP0158091A1 (en) | 1985-10-16 |
| EP0158091B1 (en) | 1989-03-29 |
| FI83582B (en) | 1991-04-15 |
| FI850821A0 (en) | 1985-02-28 |
| NO850814L (en) | 1985-08-30 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |