System and method of surfactant dosing

Abstract

A system and method of processing laundry by the determination of surface tension in a dynamic environment for surfactant concentration in industrial laundry applications. The dosage system is able to control the surfactant concentration for a recycle wash tank and preferentially the washer tank using surface tension measurements, temperature control, and correlation to the percentage of active matter based on a full dose of a commercial surfactant for the wash runs. The dosage system preferably uses a surface tensiometer able to monitor surfactant levels and to constantly dose surfactant for use in subsequent washes.

We claim:  
     
         1 . A system of surfactant dosing for maintaining a set point of surfactant level in a laundry application comprising: 
 a washer tank;    a recycle wash tank connected to the washer tank;    a dispenser; and    a tensiometer wherein: 
 the tensiometer is capable of measuring the surfactant level in the recycle wash tank;  
 the tensiometer is capable of comparing the surfactant level to the set point; and  
 the tensiometer is capable of sending signals to the dispenser.  
   
     
     
         2 . The system of  claim 1  wherein the dispenser is capable of pumping surfactant to the recycle wash tank.  
     
     
         3 . The system of  claim 1  wherein the dispenser is capable of pumping surfactant to the washer tank.  
     
     
         4 . The system of  claim 1  further comprising a converter disposed between the tensiometer and the dispenser capable of configuring and forwarding signals to the dispenser.  
     
     
         5 . The system of  claim 1  further comprising a controller disposed between the tensiometer and the dispenser wherein: 
 the controller is capable of monitoring the surfactant level; and  
 the controller is capable of activating the dispenser.  
 
     
     
         6 . The system of  claim 5  wherein the controller comprises a programmable logic controller and a signal-conditioning transmitter.  
     
     
         7 . The system of  claim 6  wherein the programmable logic controller is capable of using ladder logic to compare the signals to a constant.  
     
     
         8 . The system of  claim 1  further comprising a programmable logic controller and wherein the tensiometer comprises: 
 a keypad; and  
 at least one digital output;  
 wherein the digital output from the tensiometer is capable of activating the programmable logic controller.  
 
     
     
         9 . The system of  claim 1  further comprising: 
 a dump chest connected to the washer tank;  
 a lint screen or a lint trap connected to the dump chest; and  
 a separatory filter connected the lint screen or lint trap and connected to the recycle wash tank;  
 wherein the recycle wash tank comprises a sampling chamber such that the tensiometer is capable measuring the surfactant level of the recycle wash tank via the sampling chamber.  
 
     
     
         10 . The system of  claim 2  wherein the dispenser is capable of dosing a calculated percentage of a stroke length of the dispenser.  
     
     
         11 . A method of surfactant dosing for maintaining a set point of surfactant level in a laundry application that comprises the steps of: 
 (a) measuring the surfactant level by using a tensiometer is capable measuring the surfactant level;    (b) comparing the surfactant level to the set point;    (c) pumping surfactant if the surfactant level is lower than that the set point.    
     
     
         12 . The method of  claim 11  wherein Step (a) is accomplished by measuring the surfactant level in a recycle wash tank, wherein the recycle wash tank is connected to a washer tank.  
     
     
         13 . The method of  claim 12  wherein Step (c) is accomplished by pumping surfactant into the recycle wash tank.  
     
     
         14 . The method of  claim 12  wherein Step (c) is accomplished by pumping surfactant into the washer tank.  
     
     
         15 . The method of  claim 11  wherein Step (b) further comprises the steps of: 
 producing signals with the tensiometer;  
 converter the signals from the tensiometer; and  
 delivering the converted signals to a dispenser capable of performing Step (c).  
 
     
     
         16 . The method of  claim 11  which further comprises the step of using a controller connected to the tensiometer to accomplish Step (b).  
     
     
         17 . The method of  claim 16  wherein the controller comprises a programmable logic controller.  
     
     
         18 . The method of  claim 17  which further comprises the step of using ladder logic to compare the signals to a constant.  
     
     
         19 . The method of  claim 11  which further comprises correlating a percentage of active matter to the measured surfactant level from Step (a).  
     
     
         20 . The method of  claim 17  which further comprises the step of constructing a curve of the correlation of percentage of active matter to the measured surfactant level measurements.  
     
     
         21 . The method of  claim 11  which further comprises the step of adjusting surface tension using electronic algorithms to deliver an adjusted dosage.  
     
     
         22 . The method of  claim 21  which further comprises the steps of: 
 developing a correlation curve of active matter to surface tension; and  
 metering the dosage as a percentage of a stroke length.  
 
     
     
         23 . A system of surfactant dosing for maintaining a set point of surfactant level in a laundry application comprising: 
 a washer tank;    a dump chest connected to the washer tank;    a lint screen or a lint trap connected to the dump chest;    a separatory filter connected to the lint screen or lint trap;    a recycle wash tank connected to the separatory filter and connected to the washer tank;    a sampling chamber connected to the recycle wash tank;    a tensiometer wherein the tensiometer comprises measuring probes disposed in the sampling chamber; and    a dispenser capable of pumping surfactant to the recycle wash tank;    wherein the tensiometer is capable measuring the surfactant level and comparing the surfactant level to the set point; and    wherein the tensiometer is capable of sending signals to the dispenser.    
     
     
         24 . The system of  claim 23  further comprising a converter connected to the tensiometer and the dispenser wherein the converter is capable of converting signals from the tensiometer and sending the converted signals to the dispenser.  
     
     
         25 . The system of  claim 23  further comprising a programmable logic controller.