HEATED ROLLER

Abstract: A hollow roller or drying cylinder (2) to be rotated and to be heated as a consequence of burning fuel gas within the drying cylinder so that web material such as paper or textile material is subjected to drying heat on coming into contact with an outer surface of the cylinder (2). The cylinder (2) comprises a cylindrical heat conducting wall (4) of metal. A ribbon burner (24) for burning fuel gas supplied thereto (mixed with combustion air) through pipes (20, 22) is mounted inside the cylinder (2) and has a burner slot (26) facing towards and adjacent to an inner surface (28) of the cylinder (4). An acoustic baffle (64) to absorb sounds generated by the combustion of the fuel gas is mounted behind the burner (24) at an opposite side of the axis of rotation of the cylinder (2) to the side on which the burner is disposed. The baffle (64), which extends longitudinally of the drying cylinder (2), can comprise porous layers (66, 68) of ceramic fibres.

Description: Heated Roller This invention concerns a roller which is heated by burning fuel gas inside it. The fuel gas may be natural gas . The heated rollers concerned may be used in the treatment of materials. For example, they may be rotatable, heated drying cylinders; the material to be dried being brought into contact with an outer surface of the drying cylinders. Such material may be in web form, and may be a paper material or a textile material. The material to be dried can pass around a said heated roller to contact the heated outer surface of the roller over an arc of contact ; the outer surface being heated by conduction through a wall of the roller from the interior of the roller where the gas is burned. A problem associated with heating a hollow roller by the combustion inside it of fuel gas is the noise which accompanies the combustion. Acoustic waves are set up, these can be reflected within the roller which may also resonate, and the general reverberation creates a noise which can be unpleasant and disturbing to listen to, interfere with communication by speech, and exceed permitted limits. An object of the invention is to provide a roller to be heated internally by burning fuel gas therein in which the aforesaid noise problem can be mitigated. According to the invention there is provided a hollow roller to be heated as a consequence of burning fuel gas internally of the roller, said roller comprising a heat conducting roller wall extending about an axis to describe said roller having an outer surface formed by an outer surface of the wall, fuel gas burner means disposed within the interior of the roller to direct against an inner surface of the roller wall hot products of combustion resultant from burning the fuel gas, baffle means for absorbing sound being disposed internally of said roller, and said baffle means being disposed behind said burner means when a direction in which gas flames extend from the burner means is taken as a forwards direction. The baffle means may extend longitudinally of the roller. Preferably the baffle means extends substantially from one end of the roller to the other. The baffle means may have at least one side or edge disposed adjacent to said inner surface of the roller wall. The baffle means may comprise heat resistant fibrous material. That material may be fibrous ceramic material . The baffle means may be in the form of a panel arrangement . That panel arrangement may be disposed substantially as a chord to a circular internal cross-section of the roller. Or the panel arrangement may have a curved cross-sectional shape. Or the panel arrangement may comprise at least two component parts inclined one to the other at an angle of less than 180°. The baffle means may be disposed wholly or partly to one side of an axis of rotation of the roller, and the burner means may be disposed on the opposite side of said axis. The roller may be a rotatable drying cylinder for drying web material coming into contact with the external surface of the cylinder. The web material may be treated in web treatment apparatus comprising the said drying cylinder. The web material may be paper or textile material. The invention will now be further described, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic view, partly in section on line I- I in Fig. 2 of a first embodiment of a heated roller formed according to the invention; Fig. 2 is a diagrammatic section on line II-II in Fig. 1 ; Fig. 3 is a sectional view of a fragment of the baffle means used in Fig. 1, but shown on a larger scale than in Fig. 1; Fig. 4 is a front view of the burner means used in Fig. 1 ; Fig. 5 is a front view of alternative burner means which can be used in Fig. 1; Fig. 6 is a diagrammatic section comparable with Fig. 2 of a modification of the heated roller in Fig. 1; Fig. 7 is a diagrammatic section comparable with Fig. 2 of another modification of the heated roller in Fig. 1; Fig. 8 is a diagrammatic section comparable with fig. 2 of a further modification of the heated roller in Fig. 2 ; Fig. 9 is a view of an air supply pipe used in the rollers in Figs. 1,6 and 8 ; Fig. 10 is a view of an alternative air supply pipe for use in the rollers in Figs. 1,6 and 8; Fig. 11 is a diagrammatic view, partly in section, of yet another modification of the heater roller in Fig. 1 ; Fig. 12 is a diagrammatic view, partly in section on line XII-XII of Fig. 13 of a second embodiment of a heater roller formed according to the invention; Fig. 13 is a diagrammatic end view, along the direction of arrow XIII in Fig. 12, of said second embodiment, with parts absent; Fig. 14 is a diagrammatic view of an exhaust pipe used in the roller in Fig. 12; Fig. 15 is a diagrammatic view, partly in section on line XV-XV in Fig. 17, of a third embodiment of heated rollerformed according to the invention; Fig. 16 is a diagrammatic view, partly in section on line XVI-XVI in Fig. 17, of the roller in Fig. 15; Fig. 17 is a diagrammatic section on line XVII -XVII in Fig. 15; Fig. 18 is a sectional view of a fragment of the baffle means used in the embodiment in Fig. 15, but shown on a larger scale than in Fig. 15; Fig. 19 is an elevation of an outer tube or sleeve of an exhaust arrangement used in the embodiment in Fig. 15; Fig. 20 is an elevation of a fragment of an inner tube used in conjunction with the outer tube of Fig. 19 in the exhaust arrangement of Fig. 15, and Fig. 21 shows, partly in section and partly exploded, a fragment of the exhuast arrangmeent for Fig. 15 in which the tubes in Figs. 19 and 20 have been assembled; Fig. 22 is a diagrammatic view partly in section of a modification of the heated roller in Fig. 17, and Fig. 23 shows diagrammatically a modified arrangement of burner means for a heated roller formed according to the invention. In the drawings like reference numerals identify like or comparable parts. Figs . 1 to 4 show a heated roller 2 in the form of a rotatable drying cylinder which may be rotatably driven and can form part of a web material treatment machine, for example a drying machine, in which the web material is passed around the cylinder or otherwise comes into contact with an outer surface of the rotating cylinder for heat from that outer surface to dry the web. The web may be paper or textile material. In one example the cylinder 4 may be more than a metre in diameter and several metres in length. The cylinder 2 is formed with a cylindrical wall 4 of heat conducting material, for example a metal, which may be a steel having annular end faces from which two hollow trunnions 6 and 8 extend. A pair of durable ceramic annuli 10 and 12 is provided to line and surround each trunnion to provide heat insulation to protect anti-friction bearings 14 in which the cylinder 2 rotates. The bearings 14 are each mounted in a respective support 16 or 18 forming part of the web drying machine. A stationary fuel gas feed pipe 20 enters the cylinder 2 through the trunnion 6 and is disposed longitudinally close to the axis of rotation of the cylinder. Short pipes 22 extend from pipe 20 to an elongate, stationary burner 24. The burner 24 can be, for example, a ribbon burner having an elongate gas outlet orifice or slot 26 facing towards and adjacent to an inner surface 28 of the cylinder wall 4. The burner 24 extends longitudinally for substantially the length of the cylinder 2 so that the gas flame strip is applied to the cylinder wall substantially along the length of that wall. As represented in Fig. 4, the burner slot 26 contains in known manner corrugated strip material 30. Another form of ribbon burner is shown at 24A in Fig. 5 in which there is a plurality of spaced slots 26A along the burner length. With this burner 24A too, gas flame is applied to the inner surface of the cylinder 2 substantially along the length thereof. The feed pipe 20 receives its supply of fuel gas from a supply pipe 32 via valve means 34 which controls not only the supply of fuel gas to the pipe 20 but also the amount of combustion air which is mixed with the fuel gas in the feed pipe 20. This combustion air is supplied via a branch pipe 36 from air supply pipe 38 supplied by air blower 40. Air supply pipe 38 supplies air to a stationary air feed pipe 44 via valve means 42 controlling the amount of air to the pipe 44. The air feed pipe 44 enters the cylinder 2 through the trunnion 6 and is substantially co-axial with the axis of rotation of the cylinder. In Fig. 1 the air feed pipe terminates in an open end 46 about mid- ay along the length of cylinder 2. The feed pipes 20 and 44 are secured together and are supported in position to hold the burner 24 stationary in position by sturdy supports 48 and 50, the former being attached to both feed pipes and the latter to a closed end 52 of the gas feed pipe 20. In another example, the burner 24 or 24A herein can be a radiant panel burner which may comprise metal fibre . An open end of trunnion 8 fits into an open end of a flue pipe 54 leading to flue gases extractor means 56 (Fig. 11) , an annular gas seal 58 allowing rotation of the trunnion being provided therebetween and the flue pipe. The free end of trunnion 6 is sealed in gas tight manner by a partition 60 which is a sealing fit on feed pipes 20,44 and carries a peripheral seal 62 between the partition and the trunnion 6 which can rotate relatively to seal 62. The extractor means 56 may be an extractor fan or an eductor . An acoustic baffle 64 is provided in the form of a panel which, in Fig. 1, is of a generally rectangular shape. The baffle 64 comprises a pair of porous boards 66 and 68 formed of resin bonded ceramic fibres secured by means of bolts 70 and nuts 72 to opposite sides of a support plate or web 74 of a heat resistant metal, for example stainless steel, formed with an array of openings 76 through the support web. The ceramic fibre boards can be of known kind and may be capable of withstanding temperatures up to 1400°C and each may be 25 to 38mm thick. Some of the bolts 70 and nuts 72 are used to secure plates 78 to the baffle. These plates are mounted on struts 80 secured to the feed pipe 44 or the feed pipe 20 which thus hold the baffle 64 in position. Which, as shown in Fig. 2, is in a chord-like disposition to the circular cross-section of the inner surface 28 of the cylinder wall 4. Top and bottom sides 82 and 84 of the baffle 64 are adjacent to but spaced from the inner surface 28 of the cylinder. Also as can be seen in Figs. 1 and 2 the baffle 64 is on one side of the axis of drying cylinder 2 and the burner 24 is on the opposite side. The gas flame from the burner 24 or 24A attaches to the inner surface 28 of the cylinder 2 for a considerable circumferential arc. This gives a high driving force heat transfer to the cylinder wall 4 for the burner and results in high heat flux being imparted to the cylinder 2. The flame attachment ensures high uniform heat transfer rates over a considerable circumferential arc of the inner surface 28 of the cylinder. High heat transfer rates imparted to the cylinder wall 4 result in a considerable increase in thermal efficiency of the system. The air introduced at pressure into the cylinder 2 through the feed pipe 44 is cooling air. It can keep the burner 24 cool and can improve control of the temperature within the cylinder 2. The flow rate of the air can be varied by operation of the air control valve means 42 to achieve these effects. It is believed that the air flow also assists in reducing noise levels generated within the cylinder 2. In an emergency shutdown, such as when there is a break in the web material being dried the supply of cooling air from pipe 44 can protect the cylinder 2 from overheating particularly, for example, if control means are provided to cut off the fuel gas supply but continue the supply of cooling air. The baffle 64 can absorb acoustic waves set up due to the combustion of the fuel gas within the cylinder 2. The baffle can absorb sound waves reflected off the inner surface 28 of the cylinder and resonant frequencies. The baffle 64 becomes heated and can radiate heat onto the cylinder wall 4 thereby increasing the thermal efficiency of the system. In Fig. 1 the air feed pipe 44 may be modified by being extended as indicated by the dotted line portion 86 to be an air feed pipe of the kind shown at 44A in Fig. 9 having closed end 88 and a through slot 90 in its wall to extend substantially along the length of the interior of the cylinder 2. In Fig. 10 the air feed pipe 44A has a row of shorter, spaced slots 90A instead of the continuous longer slot 90. Fig. 6 shows the cylinder 2 in Fig. 1 modified by using the air feed pipe 44A in which the slot 90 faces towards the baffle 64 and away from the burner 24. In Fig. 7 the air feed pipe 44B is similar to the pipe 44A except that feed pipe 44B has two slots 90 or two rows of slots 90A facing along diverging directions in the general direction of the burner 24 and away from the baffle 64. In Fig. 8, the baffle 64 has a curved shape which can be substantially concentric with the cylinder 2 with an outermost curved face 91 of the baffle adjacent to but spaced from the inner surface 28 of the cylinder wall 4. The flue pipe 54, in the modification in Fig. 11, emerges from a plenum or chamber 92 fitting over the whole of the end of the cylinder 2 provided with the trunnion 8, so that the support 18 extends through the chamber wall which has a circular opening at one end defined by a flange 94 spaced by a small annular gap from an outer surface 96 of the cylinder wall 4. That gap may be occupied by a seal permitting the cylinder 4 to rotate. Besides the passage through the trunnion 8, an end wall of the cylinder 2 can have appertures 98 therethrough. The embodiment of the drying cylinder 2 in Figs. 12 to 14 has a cylindrical wall 4 closed at one end by a circular plate 100 bolted thereto and mounting a trunnion 102. At its other end the cylinder wall 4 has an internal annular rib 104 serving as a runner to rotate about a bearing comprising a stationary frame or spider 106 rotatably mounting three bearing rollers or wheels 108 supporting the end of the cylinder 2 at the rib 104 which runs on the bearing wheels. The gas feed pipe 20 is supported by the spider 106 and branches into two pipes 22 supporting the burner 24 and supplying a mixture of combustion air and fuel gas thereto. A flue pipe 54 also supported by the spider 106 is connected to extractor means, for example an eductor or extractor fan (not shown) , and supports a flue manifold 110 extending along substantially the length of the cylinder 2 adjacent to its inner surface 28. Facing that inner surface 28 is a row of elongate inlet openings 112 through the flue manifold wall. Between the flue manifold 110 and the burner 24 is the baffle 64 mounted on and supported by the fuel gas feed pipe 20. In Fig. 12 the baffle 54 is clamped to the pipe 20 by U-bolts 114. The baffle 64 is again in chord-like disposition in relation to the internal circular cross-section of the cylinder 2 but is nearer to the axis of rotation of the cylinder than in the embodiment in Fig. 1. The pipes 20 and 54 pass through a stationary cover plate 115 which fits fairly closely on them and close to the rib 104 to prevent flames emerging through the spider 106. The use of the spider 106 with bearing wheels as a support for one end of the cylinder 2 means that when the spider is dismantled there is quite a large opening in the end of the cylinder to allow relatively easy insertion or removal of the baffle 64, burner 24 and exhaust manifold 110 so these may be retrofitted to an existing cylinder 4 having an internal rib 104. Under normal or preferred operation, products of combustion in Fig. 12 are exhausted through the manifold 110 by the extractor means, thus maintaining a negative pressure which can be slight and ensuring that air leaks into the cylinder 2 rather than combustion products leaking out. If desired each manifold inlet 112 may be of a variable or different size from the others to enable a more uniform extraction of combustion products along the length of the cylinder, i.e. the combustion products are extracted at substantially the same rate at different points along the cylinder length. This is to encourage a more even heating of the cylinder wall 4 along its length. The embodiment constituting the drying cylinder 2 in Figs. 15 to 21 has the end plate 100 mounting the trunnion 102 secured to one end of the cylindrical wall 4 and another end plate 116 mounting the hollow runnion 6 secured to the other end of the cylindrical wall. The stationary feed pipe 20 supplying the fuel gas and combustion air mixture to the burner 24 supports the burner, and the pipe 20 is itself supported by support means (not shown) beyond the free end of the trunnion 6 through which the pipe so passes. The stationary flue pipe 54 also passes through the trunnion 6 and supports at one end an exhaust manifold 118 within the cylinder 2 and extending substantially the length of the cylinder. Within the trunnion 6 and cylinder 2 the flue pipe 54 and manifold 118 are substantially co-axial with the axis of rotation of the cylinder. Beyond the free end of the trunnion 6 the flue pipe 54 is supported by support means (not shown) . This flue pipe comprises a pipe portion 120 including the flue gases extractor means 56 and a thermal break and draught regulator arrangement 122, an elbow pipe 124 feeding the arrangement 122 and bolted through pipe flanges 126 and 128 (using nuts 130 and bolts 132 shown in Fig. 21) to a cylindrical connecting sleeve 134, a cylindrical manifold sleeve 136 of the manifold 118, the sleeves 134,136 being bolted together at their connecting flanges 138,140, and a cylindrical regulator tube 142 disposed internally of and co-axially with the sleeves 134,136 in a snug but rotatable fit therein. The exhaust manifold 118 has through inlet openings 144 (represented in Fig. 21 by the solid dark shading) leading into the manifold interior. These inlet openings 144 are formed by the combined effect of circular apertures 146 disposed in a row through the wall of the manifold sleeve 136 (which has a closed end 148) and a slot 150 (Fig. 20) through the wall of the regulator tube 142 which has a closed end 152. Aforesaid apertures 146 are each of substantially the same size and substantially equally spaced apart. The slot 150 extends lonitudinally of the regulator tube 142 and has a somewhat slender triangular shape which widens towards the closed end 152, in any event the slot 150 being wider adjacent the closed end 152 than the portion of slot remote from the closed end. Thus by positioning the regulator tube 142 inside the manifold sleeve 136 and rotating the regulator tube 142 about its axis the slot 150 can be brought into varying amounts of coincidence with the apertures 146 and accordingly create inlet openings 144 of varying sizes. Not only can the inlet openings 144 vary in size one from another along the row of openings but the size of a particular inlet opening 144 can also be varied. The nature of the slot 150 and the size and positioning of the apertures 146 ensures that the inlet openings 144 to the right hand end of the manifold 118 in Fig. 21 are larger than the inlet openings to the left hand end, and the largest inlet opening is at the extreme right hand end of the row of inlet openings and the smallest at the extreme left of the row. When inlet openings 144 of the desired size are obtained by adjusting the position of the regulator tube 142 it is then held in that position by an end flange 154 on the regulator tube being clamped between the flanges 126,128. The slot 150 may have other shapes when desired. The apertures 144 in the manifold sleeve 136 are disposed in substantially the same diametral plan, with respect to the cylinder 2, as the burner 24 but the apertures face in the opposite direction to the burner outlet 26. The baffle 64 comprises two baffle panels 64A and 64B each formed of the bonded ceramic fibre boards 66 and 68 secured to opposite sides of the support web 74 (see Fig. 18) which may be of a mesh or a reticulate structure formed of heat resistant metal, for example stainless steel wire. An edging strip 156 (Fig. 18) of heat resistant metal can be mounted along the peripheral sides of each baffle panel 64A, 64B and can be connected to the web 74. The baffle panels 64A, 64B are mounted on support brackets 158 which are clamped around the manifold sleeve using clamping bolts 160 and nuts 162 to hold the baffle panels in place. As can be seen in Fig. 17 at the side of the baffle 64 facing away from the ribbon burner 26 the included angle between the panels 64A, 64B is less than 180°. It is believed that the comparative closeness of opposite sides 82 and 84 of the baffle 64 in Fig. 17 to the inner surface of the cylinder wall 4 in Fig. 17 improves heat distribution along that inner surface along the length of the cylinder 2. Also heat distribution is improved because of the different sizes of the manifold inlets 144. With regard to Figs. 15 and 21, because the action of the extractor means 56 is closest to the left hand end of the exhaust manifold 118 the pressure difference between the interior of the cylinder 2 and the interior of the exhaust manifold decreases as one moves along the manifold interior from left to right in Fig. 21. Thus by progressively increasing the size of the iniets 144 from left to right the rate at which flue gases are drawn into each inlet 144 can be substantially the same from one inlet to another. Because flue gases are leaving the cylinder 2 at substantially the same rate at substantially equally spaced apart points along the length of the cylinder the chances are improved of a more even heat distribution along the inner surface 28 of the cylinder wall for one end of the cylinder to the other. A seal partition 164 about which trunnion 6 can rotate is provided to obstruct emergence of flames from the cylinder 2. In Fig. 22 the drying cylinder 2 rotates in direction A. The baffle 64 comprises the two baffle panels 64A and 64B having an included angle therebetween which is greater than 90° and less than 180 and is on the same side of the baffle as the burner 24. Without the baffle 64, a substantial boundary layer of colder gases would form next to the inner surface 28 of the cylinder 2 upstream (with respect to rotation direction A) of the cylinder. The momentum of this boundary layer can be sufficient to deflect the burner flame when the boundary layer arrives thereat and can reduce heat transfer, and may even blow out the flame. At B in Fig. 1, the edge of the baffle 64 adjacent to the inner surface 28 can have the effect of scrubbing off the boundary layer gases away from the inner surface and to some extent direct them towards the exhaust manifold 118. An upstream edge of baffle 64 in the embodiments in Figs. 1 to 19 can also have a similar scrubbing off effect . In Fig. 23 the burner 24 has a long central section 24B and end sections 24C and 24D cranked over at 172 or 170 to face the inner surfaces of end walls (or end closure plates e.g. 100 and 116 in Figs. 12, 15 and 16) of the cylinder. Fuel gas is supplied as indicated by arrow C through a control valve 174 to a venturi pump 176 supplied with combustion air by fan or blower 178. Two further control valves 180 and 182 are provided. When valve 180 is closed and valve ia7 is open, a mixture of fuel gas and combustion air is supplied to all the burner sections 24B, 24C and 24D and flames from the cranked parts 170 and 172 can heat the end of the cylinder walls. On the other hand if cooling of the end walls is required, valve 182 is closed and valve 180 is opened to enable the burner portions 24C and 24D to emit only air. When both valves 180 and 182 are closed, only the burner section 24B can heat the cylinder.

Claims: CLAIMS 1. A hollow roller to be heated as a consequence of burning fuel gas internally of the roller, said roller comprising a heat conducting roller wall extending about an axis to describe said roller having an outer surface formed by an outer surface of the wall, fuel gas burner means disposed within the interior of the roller to direct against an inner surface of the roller wall hot products of combustion resultant from burning the fuel gas, baffle means for absorbing sound being disposed internally of said roller, and said baffle means being disposed behind said burner means when a direction in which gas flames extend from the burner means is taken as a forward direction. 2. A roller as claimed in Claim 1, in which said baffle means extends longitudinally of the roller. 3 - A r °H r as claimed in Claim 2, in which said baffle means extends substantially from one end of the roller to the other end. 4 • A r °Her as claimed in any one preceding claim, in which said baffle means has sides disposed adjacent to an inner surface of the roller wall. 5* A r °Her as claimed in any one preceding claim, in which said burner means extends longitudinally of the roller. 6. A roller as claimed in any one preceding claim, in which the burner means is a ribbon burner. 7. A roller as claimed in any one of Claims 1 to 5 , in which the burner means is a radiant panel burner . 8. A roller as claimed in any one preceding claim, in which the baffle means comprises heat resistant fibrous material. 9. A roller as claimed in Claim 8, in which said fibrous material is a fibrous ceramic material. 10. A roller as claimed in Claim 8 or in Claim 9, in which the baffle means comprises at least one layer or board of resin bonded said fibrous material. 11. A roller as claimed in Claim 8, in which said baffle means comprises layers of said fibrous material mounted on opposite sides of a support between at least two of said layers. 12. A roller as claimed in Claim 11, in which said support is a metal web with openings therethrough. 13. A roller as claimed in any one preceding claim, in which the baffle means is in the form of at least one panel. 14. A roller as claimed in any one of Claims 1 to 12, in which the baffle means is in the form of a panel arrangement . 15. A roller as claimed in Claim 14, in which, in cross-section transverse to the axis of the roller, the said inner surface of the roller describes a circle about said axis, and said panel arrangement is disposed substantially as a chord to said circle. 16. A roller as claimed in Claim 14, in which the panel arrangement has a curved cross-sectional shape . 17. A roller as claimed in Claim 14, in which said panel arrangement comprises at least two component parts inclined one to another at an angle of less than 180 . 18. A roller as claimed in Claim 17, in which said angle is at a side of the panel arrangement remote from said burner means . 19. A roller as claimed in Claim 17, in which said angle is at the same side of the panel arrangement as the burner means . 20. A roller as claimed in any one of Claims 1 to 17, in which said baffle means is disposed at least in part to one side of the axis of rotation of the roller. 21. A roller as claimed in Claim 20, in which the baffle means is disposed on one side of the axis and the burner means is disposed on the opposite side of said axis . 22. A roller as claimed in any one preceding claim, further comprising means to introduce air under pressure into the interior of the roller separately from any gaseous substance introduced by said burner means . 23. A roller as claimed in Claim 22, in which said air is cooling air. 24. A roller as claimed in any one preceding Claim, further comprising flue means through which gases can leave the interior of the roller. 25. A roller as claimed in Claim 24, in which said flue means comprises driven flue gas extractor means . 26. A roller as claimed in Claim 24 or in Claim 25, in which said flue means comprises a tube arrangement disposed inside the roller, and said tube arrangement having a plurality of flue gas inlet openings therein leading into the interior of the tube from the interior of the roller. 27. A roller as claimed in Claim 26, in which at least one said of said inlet openings is of a different size to at least one other said inlet opening. 28. A roller as claimed in Claim 26, in which the size of each of two or more of said inlet openings is variable. 29. A roller as claimed in any one preceding claim, in which the burner means has a main portion and an end portion and means being arranged to supply both said portions with a mixture of fuel gas and combustion air, or to supply the main portion with fuel gas and combustion air whilst supplying the end portion with air to cool an end part of the roller. 30. A roller as claimed in Claim 29, in which the supply of any gaseous medium to said end portion of the burner means is interruptable . 31. A roller as claimed in any one preceding claim, said roller being a rotatable drying cylinder for drying web material coming into contact with a periphery of the cylinder. 32. A web material treatment apparatus comprising a drying cylinder as claimed in Claim 31. 33. A roller as claimed in Claim 31 or apparatus as claimed in Claim 32, in which the web material is paper. 34. A roller as claimed in Claim 31 or apparatus as claimed in Claim 32, in which the web material is textile material. 35. A hollow roller to be heated as a consequence of burning fuel gas internally of the roller, said roller being substantially as hereinbefore described with reference to Figs . 1 to 4, or Figs. 1 to 3 and Fig. 5, or Figs. 1 to 4 and Fig. 9, or Figs. 1 to 4 and Fig. 10, or Figs. 1 to 3 and Figs. 5 and 9, or Figs 1 to 3 and Figs. 5 and 10, or Fig. 6 or Fig. 7, or Figs. 8 and 9, or Figs. 8 and 10, or Figs. 1 to 4 and 11, or Figs. 1 to 4, 9 and 11, or Figs. 12 to 14, or Figs. 15 to 21 of the accompanying drawings, or to said Figs. 15 to 21 modified according to Fig. 22 of the accompanying drawings, or a roller as claimed hereinbefore in this claim in which the burner means 24 or 24A is substantially as hereinbefore described with reference to Fig. 23 of the accompanying drawings.

Inventors: BAKER MARTYN CAREY, SIDHU BALDIP SINGH, SOMERVELL THOMAS RICHARD, BAKER, MARTYN, CAREY, SIDHU, BALDIP, SINGH, SOMERVELL, THOMAS, RICHARD
Applicants: BAKER MARTYN CAREY, BRITISH GAS PLC, SIDHU BALDIP SINGH, SOMERVELL THOMAS RICHARD, BAKER, MARTYN, CAREY, BG PLC, SIDHU, BALDIP, SINGH, SOMERVELL, THOMAS, RICHARD
Application year: 1999
Main classification: D21F5
IPC codes: D21F5