Method and apparatus for viscous processing

Claim 2

Method according to claim 2, wherein said dry bulb temperature is measured near the point where the processing composition is applied to the web.

Claim 3

Method according to claim 1 wherein the humidifying liquid is an aqueous solution containing a dissolved substance at a concentration lower than the value at which the said solution is in equilibrium with the relative humidity in the proCessing zone at the required wet bulb temperature.

Claim 4

Method according to claim 1, wherein the circulation of the atmosphere through the humidifying and processing zone occurs in a closed circuit.

Claim 5

Method according to claim 5, wherein ambient air is introduced into the closed circuit between the processing zone and the humidifying zone, in order to maintain an overpressure in the circuit.

Claim 6

Method according to claim 1, wherein the wet bulb temperature of the atmosphere in the processing zone is about 1 to 5* C. lower than the temperature of the processing composition as it is applied to the web.

Claim 7

Web-processing apparatus of the type wherein the processing composition is applied in a thin layer onto a continuously advancing web, and wherein said web and said applied processing composition remain for a predetermined period in a processing chamber, comprising means for maintaining the atmosphere in said processing chamber at a substantially constant wet bulb temperature, comprising: a humidifier for introducing an excess of water in an atmosphere so that the atmosphere comes substantially into equilibrium with the water vapor pressure, first heater means for heating said water which is fed to said humidifier to a temperature so that the wet bulb temperature of the humidified atmosphere is lower than that required in the processing chamber, a sink for collecting the excess of water from the humidifier and pump means for pumping the water from said sink through said first heater means to said humidifier, second heater means for increasing the temperature of the humidified atmosphere, and blower means for circulating said humidified and heated atmosphere through the processing chamber and then back again to said humidifier.

Claim 8

An apparatus according to claim 8, wherein water supply and air supply means are provided for compensating losses of humidified atmosphere.

Claim 9

Apparatus according to claim 8, wherein the humidifying and the heating of the atmosphere occur in a chamber separate from the processing chamber.

Claim 10

Apparatus according to claim 8, wherein said blower means circulates the air in a direction opposite to the direction according to which water is sprayed into the air.

Claim 11

Apparatus according to claim 8, wherein said first heater means is thermostatically controlled by sensing means measuring the temperature of the water collected in the sink.

Claim 12

Apparatus according to claim 8, wherein said second heater means is controlled by sensing means measuring the dry bulb temperature in the processing chamber.

Claim 13

Apparatus according to statement 13, wherein said sensing means is located near the area where the processing composition is applied to the web.

Claim 14

Apparatus according to claim 8, wherein a continuous overpressure is maintained in the processing chamber.

Claim 15

Apparatus according to claim 8, wherein the thermostatic control of the second heater means is arranged to obtain in the processing chamber a wet bulb temperature which is by 1 to 5* C. lower than the temperature of the developing composition which is applied to the web.