Drying and gas or vapor contact with solids – Apparatus – With means to treat gas or vapor
Patent
1991-02-28
1992-11-03
Bennet, Henry A.
Drying and gas or vapor contact with solids
Apparatus
With means to treat gas or vapor
34 1W, 34 4, 34 18, 34155, F26B 332
Patent
active
051597632
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a drying element for use in a printer as well as to a drying unit composed of drying elements of this type.
A drying element according to the preamble of claim 1 is known from U.S. Pat. No. 2,683,939. In the latter, the rod-shaped heating element is a conventional heating rod, which is located inside the heating tube and is in direct contact with the blown air to be heated. An arrangement of this type is suitable for heating the blown air, if there is no need to transmit a high thermal output to the blown air. With the very high conveying speeds of the printed products, one requires large quantities of very hot blown air, in order that the printed products can be dried reliably on the short path before reaching the next printing station.
Whereas hot air drying elements are preferred for drying water varnishes, such as are used in particular as a clear varnish over the printing inks, in order to give the surface of the finished products a lustre, infra-red radiation drying elements are preferably used for drying conventional offset inks and for drying oil varnishes.
It was also already proposed (see EP-A-0080448), to use a combined radiation/hot air drying element for drying printed products. In the drying element described in EP-A-0080448, a plurality of blower ducts following each other in the conveying direction is defined by a wall folded in a zig-zag manner, whereof the points facing the conveying path are provided with blown air discharge openings, whereas infra-red radiators are located in the gaps between the undulations. The radiation emitted by the latter partly directly reaches the surface of the printed products, partly it serves for heating the wall having zig-zag undulations and receiving the blown air on the rear side.
A combined drying element of this type is suitable for use with those printing inks which respond both to radiation drying as well as hot air drying. However, if one wished to carry out exclusively hot air drying or radiation drying with a drying element of this type, as would be advantageous for certain applications, this is not possible.
Furthermore, ultraviolet radiation drying elements are used for special varnishes and printing inks, which contain pre-polymerised synthetic materials. Not solely on account of the installation of very powerful UV radiators, but also of radiation protection and of the extraction of the ozone produced by the UV-rays, UV drying requires extensive special measures, so that correspondingly equipped printers will always be used to capacity in conjunction with ultraviolet drying.
On the other hand, in the case of infra-red drying and hot air drying, a change-over would often be appropriate, if other printing supports are to be processed on a given machine. However, this change-over presently fails in that infra-red driers and blown air driers have a different space requirement: the drying of the printed products may be brought about in a very compact space with infra-red drying; on the contrary, conventional blown air driers require a great deal of space. air in large quantities, so that a blown air drying unit constructed therewith has a compact construction so that a conventional infra-red drier can be exchanged simply therefor.
This object is achieved according to the invention by a drying element described hereafter.
In the drying element according to the invention, a rod-shaped infra-red radiator is used to produce a high heat output in a very compact space. The transfer of this heat output to the blown air first of all takes place by absorption on a heating tube extending parallel to the infrared radiator. The blown air to be heated is passed through the latter. The heating tube is in turn arranged upstream of the blower duct, which delivers the heated air.
On the one hand, one thus has an effective, intensive transfer of heat between the infra-red radiator and the heating tube, which could not be achieved by blowing the air directly past the infra-red radiator. Since the entire heating of the blown air is terminated
REFERENCES:
patent: 2683939 (1954-07-01), Meltzer
patent: 3178831 (1965-04-01), Howlett
patent: 3720002 (1973-03-01), Martin
patent: 3894343 (1975-07-01), Pray et al.
patent: 4727655 (1988-03-01), Jacobi, Jr.
patent: 4854052 (1989-08-01), Korpela
patent: 4981433 (1991-01-01), Matsumoto et al.
Bennet Henry A.
Gromada Denise L. F.
Philpitt Fred
LandOfFree
Drying elements does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Drying elements, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Drying elements will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2043363