Apparatus and method for controlling moisture in the manufacture of glass fiber insulation

Abstract

Apparatus, systems and methods for monitoring and controlling the amount of moisture introduced into the forming hood area in the manufacture of mineral fiber insulation products. Moisture from coolant liquids, binder dispersions and binder diluents are all introduced deliberately into a forming hood; ambient moisture and water from combustion are additional sources. A series of global variable control valves, one for each fluid system; as well as individual variable control valves for each fiberizing unit are provided with associated meters. Sensors monitor fibrous pack conditions and ambient conditions and provide inputs to the valve control system. A specific 3-ring liquid dispensing system is also disclosed.

1 . A method of making a fibrous product comprising;
 attenuating molten material into fibers at a plurality of fiberizing units associated with a conveyor moving in a machine direction, and directing the fibers toward the conveyor to form a fibrous pack;   spraying the fibers with at least one liquid selected from a coolant liquid, a binder diluent, a dispersion of curable binder and mixtures thereof;   curing the binder in the pack;   measuring at least one pack property before or after curing to obtain a feedback measurement, said pack property selected from (a) the thickness of the uncured pack, (b) uniformity of the uncured pack thickness, (c) the thickness of the cured pack, (d) uniformity of the cured pack thickness, (e) the uniformity of the moisture distribution in the uncured pack, (f) uniformity of vertical pack density in the uncured pack, (g) uniformity of vertical pack density in the cured pack, and (h) degree of cure in the cured pack; and   controlling the flow rate of at least one liquid sprayed at at least one fiberizing unit in response to the feedback measurement.   
     
     
         2 . The method of  claim 1  wherein the step of controlling the flow rate of at least one liquid comprises controlling the flow of coolant liquid. 
     
     
         3 . The method of  claim 2  wherein the step of controlling the flow of coolant liquid includes adjusting the coolant liquid flow to at least one fiberizing unit differently from the flow to at least one other fiberizing unit. 
     
     
         4 . The method of  claim 1  wherein the step of controlling the flow rate of at least one liquid comprises controlling the flow of binder diluent. 
     
     
         5 . The method of  claim 4  wherein the step of controlling the flow of binder diluent includes adjusting the binder diluent flow to at least one fiberizing unit differently from the flow to at least one other fiberizing unit. 
     
     
         6 . The method of  claim 1  wherein the feedback measurement is compared to a target to decide if a flow rate should be adjusted upward or downward. 
     
     
         7 . The method of  claim 1  wherein the feedback measurement is the thickness of the uncured pack. 
     
     
         8 . The method of  claim 7  wherein flow of a liquid is adjusted upward if a pack thickness feedback measurement is less than a target. 
     
     
         9 . The method of  claim 7  wherein flow of a liquid is adjusted downward if a pack thickness feedback measurement is more than a target. 
     
     
         10 . The method of  claim 1  wherein the feedback measurement is the degree of cure of the cured pack. 
     
     
         11 . The method of  claim 1  wherein the feedback measurement is provided continuously during a manufacturing run and the step of controlling the flow rate of at least one liquid is repeated continuously. 
     
     
         12 . The method of  claim 1  wherein the feedback measurement is provided at time increments during a manufacturing run and the step of controlling the flow rate of at least one liquid is repeated at each time increment. 
     
     
         13 . The method of  claim 1  wherein the at least one pack property measured as a feedback measurement is selected from: the thickness of the uncured pack; the uniformity of the moisture distribution in the uncured pack; the thickness of the cured pack; and the degree of cure in the cured pack. 
     
     
         14 . A manufacturing system for making a fibrous product, said system comprising;
 a plurality of fiberizing units associated with a conveyor movable in a machine direction, each fiberizing unit including: (a) a fiberizer adapted to form fibers from a source of molten material; (b) a blower for directing the fibers toward the conveyor to form a fibrous pack; and (c) a liquid dispensing system for spraying the fibers with a liquid selected from a coolant liquid, a binder diluent, a dispersion of curable binder and mixtures thereof;   a sensor for measuring at least one pack property before or after curing to obtain a feedback measurement, said pack property selected from (a) the thickness of the uncured pack, (b) uniformity of the uncured pack thickness, (c) the thickness of the cured pack, (d) uniformity of the cured pack thickness, (e) the uniformity of the moisture distribution in the uncured pack, (f) uniformity of vertical pack density in the uncured pack, (g) uniformity of vertical pack density in the cured pack, and (h) degree of cure in the cured pack;   an oven downstream from the fiberizing units for curing the binder in the pack; and   a fluid control system for varying the rate of at least one liquid delivered at at least one fiberizing unit in response to a signal correlating to said feedback measurement.   
     
     
         15 . The manufacturing system of  claim 14  further comprising a comparator to compare the feedback measurement to a stored target value and to generate a signal in response to the comparison. 
     
     
         16 . The manufacturing system of  claim 15  wherein the comparator generates a signal conveying the magnitude and direction of deviation from the target. 
     
     
         17 . The manufacturing system of  claim 14  wherein the fluid control system further comprises a plurality of control valves for independently setting the flow rate of coolant liquid delivered to the coolant dispensing system of each of the fiberizing units. 
     
     
         18 . The manufacturing system of  claim 17  further comprising a plurality of meters for monitoring the independent flow rate of coolant liquid to each of the plurality of fiberizing units. 
     
     
         19 . The manufacturing system of  claim 14  wherein the fluid control system further comprises a plurality of control valves for independently setting the flow rate of binder diluent delivered to an optional binder diluent system of each of the fiberizing units. 
     
     
         20 . The manufacturing system of  claim 19  further comprising a plurality of meters for monitoring the independent flow rate of binder diluent to each of the plurality of fiberizing units. 
     
     
         21 . A process for making a fibrous product comprising:
 attenuating a molten material into fibers at a plurality of fiberizing units associated with a conveyor moving in a machine direction,   directing the fibers toward the conveyor to form a fibrous pack, spraying the fibers with at least one liquid selected from a coolant liquid, a binder diluent, a dispersion of curable binder and mixtures thereof, and   curing the fibrous pack;   wherein the flow rate of at least one liquid sprayed onto the fibers is controlled to achieve liquid flow at or near the optimal level on an S-curve obtained for that product by plotting the ramp height against liquid flow.   
     
     
         22 . The process of  claim 21 , wherein the optimal level is above an inflection points where the first derivative reaches a maximum. 
     
     
         23 . The process of  claim 21 , wherein the optimal level is between the point where a second derivative exhibits a minimum and where it approaches zero again at higher flow. 
     
     
         24 . The process of  claim 21 , wherein the flow rate of coolant liquid sprayed onto the fibers is controlled to achieve liquid flow at or near the optimal level on an S-curve obtained for that product by plotting the ramp height against coolant liquid flow.