Drying and gas or vapor contact with solids – Material treated by electromagnetic energy – Infrared energy
Patent
1993-10-19
1995-08-15
Gromada, Denise L.
Drying and gas or vapor contact with solids
Material treated by electromagnetic energy
Infrared energy
34273, 34420, 34 68, F26B 334
Patent
active
054408210
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method of treating a continuous material web, particularly a paper web, according to the preamble to patent claim 1. Also, the invention relates to a device designed to carry out the method according to patent claim 1, which device is defined in more detail in the first device claim.
When paper materials are dried, a continuous paper web is run past one or several arrays of infrared heat elements. These elements comprise infrared lamps, mounted in reflector frameworks and separated from the paper web by means of glass plates in order to reduce the fire hazard and protect the lamps. Thus, the lamps must then be cooled and also the glass plates and the holders of the latter, because very high temperatures are reached. In order to obtain such a cooling, the area behind the reflector frameworks and their sheets as well as the glass holders is usually pressurized and the cooling air which is used is allowed through a system of cavities to flow past all the parts which are to be cooled and finally to leave the heat elements and flow against the paper web, from which the air is sucked and possibly reused in the drying process.
As to the above-mentioned conventional infrared heat elements the cooling air flows out usually through lines of holes or not aerodynamicly designed gaps across the web, which means that the cooling air is diffused very quickly close to the holes and reaches the paper web with a comparatively low speed. The speed usually is so low, that the boundary layer of humid air along the paper web surface and following it is not completely broken through. Consequently, the cooling air which flows against the paper web does not have a sufficient drying action, and thus several infrared heat elements are needed and/or an increased radiation intensity and amount of supplied energy. Also, when hole patterns are used, they may not cover the paper web evenly in the perpendicular direction, a streak effect and consequently an uneven drying effect being obtained. Also, the holes and the gaps respectively cannot be adjusted and thus, the cooling air supply cannot be adjusted afterwards. The manufacturing and/or assembly costs can also be troublesome in conventional plants.
WO-A-87/005644 relates to an air-float drier, particularly for paper webs, a number of units including ventilation and infrared heat radiation devices being mounted on alternately opposite sides of a web which is to be dried. By means of the ventilation equipment air jets are directed substantially parallel to the web and the humid boundary layer of which consequently is not substantially influenced by the air jets, the main task of which is to bring about a pressurization in front of the infrared heat radiation equipment in order to bend the web away from said equipment and support or stretch it in this way. As is realized, the entire drying device is very bulky and expensive as regards its manufacturing, assembly and operation, its energy consumption being very large. One of the drawbacks of the device as to its drying effect is also that the ventilation air, which is supplied against the paper web, is not allowed to pass through the infrared heat radiation equipment to become heated there to an elevated and consequently drying-efficient temperature but is circulated around said equipment, whereas the air which passes through said equipment is removed through cavities 23 and 31 to be recirculated within the plant. The dimensions of the units are large and consequently the drying units of the entire assembly are very bulky, and how the ventilation air is taken care of is not discussed.
SE-B-404 213 relates to a device for drying a moving material web without a heat radiation equipment, the ventilation air being ejected against the material web through a screen of holes, which have different fimensions. It is true that the air is ejected perpendicularly to the web surface, a continuous air-float effect being obtained, but the air stream unresiliently hits the boundary layer on the material web without bein
REFERENCES:
patent: 3623235 (1971-11-01), Smith, Jr.
patent: 4586268 (1986-05-01), Fleissner
patent: 4783908 (1988-11-01), Pabst
patent: 4882852 (1989-11-01), Kautto
patent: 5216820 (1993-06-01), Green et al.
patent: 5317127 (1994-05-01), Brewster, Jr. et al.
Gromada Denise L.
Infrarodteknik AB
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