US 4,756,091 A · Hybrid high-velocity heated air/infra-red drying oven

Abstract

A hybrid oven for drying a coating on a continuous web is disclosed, including a chamber, a plenum for collecting and delivering heated air at high velocity adjacent said chamber, a plurality of air impingement nozzles interconnecting said plenum and said chamber and directing heating air from the plenum to the web being dried, and one or more controllable infra-red heaters disposed between said air nozzles including at least one infra-red element, a sensor for providing a control signal relative to temperature and controller means for controlling power to the infra-red element. The sensor senses that the infra-red element is operating at less than a predetermined temperature and is providing less than a required infra-red output, whereby the controller provides a higher voltage until the predetermined infra-red output is reached.

Claims14

Dependent claims

A hybrid oven for the drying of a coating on a continuous web comprising, in combination:

a chamber;
plenum means for collecting and delivering heated air at high velocity adjacent said chamber;
a plurality of air impingement nozzle interconnecting said plenum means and said chamber;
directing heating air from the plenum means to the coated continuous web being dried;
said air nozzles being disposed at predetermined intervals about the chamber;
one or more controllable infra-red heaters medially disposed between said air nozzles, comprising, in turn;
at least one infra-red element normally operable within a given voltage range;
thermocouple means for providing a control signal relative to the element temperature, said thermocouple means embedded within the outer sheating of said infra-red element;
and,
infra-red controller means for increasing and decreasing power to said infra-red element, said infra-red controller means capable of providing voltages at levels substantially higher than the upper limit of the rated voltage range for said infra-red element;
whereby, upon said thermal sensor means sensing that said infra-red element is operating at least than the predetermined temperature and is providing less than required infra-red output, the infra-red controller means can provide higher voltages until the predetermined infra-red output is reached.

8 more elements

In infra-red heater with a temperature controller for a hybrid oven utilizing both high velocity air and infra-red sources comprising:

an infra-red element normally operable within a given voltage range;
thermocouple means for monitoring the temperature of said source, said thermocouple means embedded the outer sheathing of said infra-red element;
and,
temperature control means for cooperative functional relationship with said temperature sensor means, said temperature control means capable of providing voltages at levels substantially higher than said given normal range increasing power to said infra-red element upon decreasing sensed temperature and decreasing power to said infra-red source upon increasing sensed temperature;
whereby, upon convected air impinging on and cooling said infra-red element, the temperature control, the element temperature control means provides higher voltages until the required output is reached.

2 more elements

A method of drying a continuous web having a solvent-laden coating thereon by utilizing a a hybrid drying chamber having a gas heater for supplying heated high-velocity air and an adjustable infra-red source, element sensor means for detecting element temperature;

infra-red source control means for increasing and decreasing supply voltage to said infra-red source;
chamber sensor means for detecting chamber temperature;
gas-inflow control means for increasing and decreasing the gas supply to said gas heater;
and, programmable controller means for storing drying parameters, for receiving sensed temperatures and for replicating drying contitions;
said method comprising the steps of:
(a) conveying said continuous web through said drying chamber;
(b) impinging said heated high velocity air onto said continuous web;
(c) simultaneously with step b., exposing said continuous web to radiation from said adjustable infra-red source at a predetermined element temperature;
(d) cooling the infra-red source by impingment of deflected high velocity air with solvent migrating from the said continuous web;
(e) adjusting the infra-red source to maintain said predetermined element temperature;
1. sensing said element temperature;
2. programming the power levels to the infra-red source to predetermine element temperature;
3. upon sensing temperature deviation from predetermined element temperature, automatically overriding the programmed adjustment and driving the infra-red source at power levels to correct said deviation;
(f) continuously throttling the gas heater to maintain air impingement temperature at a constant level;
1. sensing said chamber temperature;
2. programming the gas supply to the gas heater to predetermine impingement air temperature;
and
3. upon sensing temperature deviation from predetermined chamber temperature, automatically overriding the programmed adjustment and throttling the gas supply to maintain chamber temperature.

15 more elements

Dependencies are inferred from the claim text.

Hybrid high-velocity heated air/infra-red drying oven

Life of this patent

Hybrid high-velocity heated air/infra-red drying oven

Life of this patent

Abstract

Claims14