Apparatus for the generation of gaseous formaldehyde from formaldehyde polymer

Claim 1

IN AN APPARATUS FOR GENERATING GASEOUS FORMALDEHYDE FROM A FORMALDEHYDE POLYMER COMPRISING A. ONE OR MORE MIXING TANKS FOR PREPARING A DISPERSION OF THE FORMALDEHYDE OLYMER IN A LIQUID CARRIER, B. A FEED TANK FOR RECEIVING THE DISPERSION FROM THE MXING TANK AND FEEDING THE DISPERSION TO THE EVAPORATOR SET FORTH BELOW, C. AN EVAPORATOR FOR HEATING THE DISPERSION AT THE TEMPERATURE OF FORMALDEHYDE GAS GENERATION, AND D. A COOLER FOR COOLING THE LIQUID CARRIER DISCHRGED FROM THE EVAPORATOR, THE IMPROVEMENT WHICH COMPRISES: SAID FOUR MEMBERS (A), (B), (C) AND (D) ARE CONNECTED IN SERIES IN THAT ORDER, SAID MIXING TANK (A) BEING CONNECTED TO A MEANS FOR FEEDING YHE FORMALDEHYDE POLYMER AS FINELY DIVIDED PARTICLES TO SAID MIXING TANK (A), AND SAID EVAPORATOR (B) BEING PROVIDED AT THE UPPER PART THEREOF WITHIN AN INLET FEED MEANS COMPRISING AN OVERFLOW MEANS FOR MAKING THE DISPERSION FLOW INTO THE EVAPORATOR IN THE STATE OF OVERFLOW, SAID EVAPORATOR FURTHER HAVING A FORMALDEHYDE GAS DISCHARGE CONDUIT, LIQUID LEVEL CONTROL MEANS HAVING UPPER AND LOWER LIQUID LEVEL DETECTING PROBES, BOTH PROBES BEING DISPOSED BELOW SAID FORMALDEHYDE GAS DISCHARGE CONDUIT AND A LIQUID CARRIER DISCHARGE MEANS DISPOSED BELOW SAID LOWER PROBE, SAID LIQUID LEVEL CONTROL MEANS MAINTAINING THE FREE SURFACE OF THE LIQUID CARRIER COLLECTED AT THE BOTTOM OF THE EVAPORATOR AT A HEIGHT BETWEEN THE DETECTING PROBES BY DISCHARGING THE LIQUID CARRIER FROM THE BOTTOM OF THE EVAPORATOR IN RESPONSE TO A SIGNAL FROM THE LIQUID LEVEL CONTROL MEANS.

Claim 10

An apparatus for generating gaseous formaldehyde from a formaldehyde polymer, comprising: at least one mixing tank for preparing a dispersion of the formaldehyde polymer in a carrier liquid, a first conduit for discharging the dispersion from the mixing tank and a first control valve in said first conduit; a feed tank for receiving the dispersion from the first conduit, a first pair of upper and lower liquid level detecting probes in the feed tank, said probes being connected to control opening and closing of said first control valve to maintain the level of the dispersion in the feed tank between said first pair of probes, said feed tank having a second conduit for discharging the dispersion therefrom; an evaporator for receiving the dispersion from the second conduit, said evaporator having a feed nozzle at the upper end thereof and connected to said second conduit, said feed nozzle having an upwardly opening discharge opening so that the dispersion overflows from said discharge opening into said evaporator, said evaporator having means for heating the dispersion at the temperature of formaldehyde gas generation, said evaporator having a formaldehyde gas discharge conduit, a second pair of upper and lower liquid level detecting probes disposed below said formaldehyde gas discharge conduit and a carrier liquid discharge conduit disposed below said lower probe of said second pair of probes, said carrier liquid discharge conduit having a second control valve therein, said second pair of probes being connected to control opening and closing of said second control valve to continuously maintain the level of the carrier liquid in the evaporator between said second pair of probes; a cooler connected to the carrier liquid discharge conduit for cooling the carrier liquid discharged from the evaporator; and means connected to the cooler for feeding the cooled carrier liquid to said mixing tank.

Claim 11

An apparatus for generating gaseous formaldehyde from a formaldehyde polymer, comprising: at least one mixing tank for preparing a dispersion of the formaldehyde polymer in a carrier liquid, a first conduit for discharging the dispersion from the mixing tank and a first control valve in said first conduit; a feed tank for receiving the dispersion from the first conduit, a first pair of upper and lower liquid level detecting probes in the feed tank, said probes being connected to control opening and closing of said first control valve to maintain the level of the dispersion in the feed tank between said first pair of probes, said feed tank having a second conduit for discharging the dispersion therefrom; an evaporator for receiving the dispersion from the second conduit, said evaporator having a feed nozzle at the upper end thereof and connected to said second conduit, said feed nozzle having an upwardly opening discharge opening so that the dispersion overflows from said discharge opening into said evaporator, said evaporator having means for heating the dispersion at the temperature of formaldehyde gas generation, said evaporator having a formaldehyde gas discharge conduit, a second pair of upper and lower liquid level detecting probes disposed below said formaldehyde gas discharge conduit and a carrier liquid discharge conduit disposed below said lower probe of said second pair of probes, said carrier liquid discharge conduit having a second control valve therein, said second pair of probes being connected to control opening and closing of said second control valve to continuously maintain the level of the carrier liquid in the evaporator between said second pair of probes; a cooler connected to the carrier liquid discharge conduit for cooling the carrier liquid discharged from the evaporator; and means connected to the cooler for feeding the cooled carrier liquid to said mixing tank.