Method for preventing pack-out in pumping system

Abstract

A method for preventing pack-out in a system for pumping hybrid hot-melt material comprises monitoring activity of a pump that pumps hybrid hot-melt material, shutting off a heater that melts pumped hybrid hot-melt material at an inactivity threshold level, and relieving pump pressure.

1 . A method for preventing pack-out in a system for pumping hybrid material, the method comprising:
 monitoring activity of a pump that pumps hybrid material;   shutting off a heater that melts pumped hybrid material at an inactivity threshold level; and   relieving pump pressure.   
     
     
         2 . The method of  claim 1  and further comprising:
 solidifying the hybrid material in the heater before relieving pump pressure. 
 
     
     
         3 . The method of  claim 1  wherein relieving pump pressure comprises routing pressurized hybrid material from a pump outlet to a pump inlet. 
     
     
         4 . The method of  claim 1  wherein relieving pump pressure comprises opening a relief valve. 
     
     
         5 . The method of  claim 1  and further comprising:
 powering off a motor that drives the pump at the inactivity threshold level. 
 
     
     
         6 . The method of  claim 1  wherein the inactivity threshold comprises a period of time for which the pump undergoes no movement. 
     
     
         7 . The method of  claim 1  and further comprising:
 reducing heat output of the heater at an idle threshold level before shutting off the heater at the inactivity threshold. 
 
     
     
         8 . The method of  claim 7  wherein the inactivity threshold comprises a period of time longer than a period of time comprising the idle threshold. 
     
     
         9 . The method of  claim 1  and further comprising:
 reactivating the system. 
 
     
     
         10 . The method of  claim 9  wherein reactivating the system comprises:
 pressurizing the pump; and 
 activating the heater. 
 
     
     
         11 . The method of  claim 10  wherein pressurizing the pump comprises:
 closing a pump relief; and 
 powering a pump motor. 
 
     
     
         12 . The method of  claim 9  wherein reactivating the system comprises:
 automatically reactivating the system. 
 
     
     
         13 . The method of  claim 1  wherein monitoring activity of the pump comprises determining a position of a pump shaft or determining a position of a dispenser lever. 
     
     
         14 . A material pumping system comprising:
 a pump that pumps material, the pump having an inlet and an outlet;   a heater that receives pumped material from the outlet;   a dispenser that receives heated pumped material from the heater; and   electronics that monitors activity of the pump and is configured to reduce output of the heater and pump at threshold levels of inactivity.   
     
     
         15 . The material pumping system of  claim 14  wherein the heater is coupled to the dispenser and is spaced from the pump outlet by a hose. 
     
     
         16 . The material pumping system of  claim 14  and further comprising:
 a position sensor coupled to the pump and in electronic communication with the electronics. 
 
     
     
         17 . The material pumping system of  claim 14  and further comprising:
 a relief valve positioned in a return line fluidly coupling the inlet with the outlet and in electronic communication with the electronics. 
 
     
     
         18 . The material pumping system of  claim 17  and further comprising:
 a material hopper connected to the return line between the pump inlet and pump outlet. 
 
     
     
         19 . The material pumping system of  claim 14  and further comprising:
 a motor configured to drive the pump. 
 
     
     
         20 . The material pumping system of  claim 14  wherein:
 the electronics are configured to shut-off the heater and pump after detecting that the pump has been inactive for a first period of time. 
 
     
     
         21 . The material pumping system of  claim 20  wherein:
 the electronics are configured to reduce output of the heater after detecting that the pump has been inactive for a second period of time less than first period of time. 
 
     
     
         22 . A method for preventing pack-out in a system for pumping hybrid hot-melt material, the method comprising:
 pumping hybrid hot-melt material with a pump;   heating the hybrid hot-melt material with a heater;   detecting activity of the pump;   determining a first period of inactivity;   reducing heat output of the heater; and   depressurizing the pump.   
     
     
         23 . The method of  claim 22  wherein reducing heat output of the heater comprises powering off the heater. 
     
     
         24 . The method of  claim 23  wherein depressurizing the pump comprises turning off a pump motor. 
     
     
         25 . The method of  claim 24  wherein depressurizing the pump further comprises opening a pressure relieve valve fluidly coupled to an outlet of the pump.