Solar-powered waste compactor, method of powering a waste compactor, and hydraulic unit therefor

Abstract

A hydraulic power device usable to power a compactor ram of a waste compactor is provided. The hydraulic power device includes a pump assembly having first and second pumps for providing pressurized hydraulic fluid to at least one hydraulic cylinder and piston assembly associated with the compactor ram. A battery is provided for storing energy and for providing energy to the pump assembly. A solar panel converts solar energy and charges the battery. A pump control unit simultaneously operates the pumps when an operating pressure of the pump assembly is less than a predetermined threshold and operates only the first pump when the operating pressure of the pump assembly is greater than the predetermined threshold.

1 - 21 . (canceled) 
     
     
         22 . A method of powering a compactor ram of a waste compactor, comprising:
 operating a pump assembly including a first pump and a second pump to pressurize a hydraulic cylinder during a duty cycle, the hydraulic cylinder having a piston assembly associated with moving a compactor ram and wherein said operating of the pump assembly comprises a first stage in which said operating of the pump assembly provides an initial fluid output from the pump assembly and a second stage in which said operating of the pump assembly provides an alternate fluid output from the pump assembly.   
     
     
         23 . The method of  claim 22 , wherein the first stage of the duty cycle comprises simultaneously operating both pumps, and the second stage of the duty cycle comprises operating the first pump but not the second pump. 
     
     
         24 . The method of  claim 22 , wherein the initial fluid output is provided when an operating pressure of the pump assembly is less than a predetermined threshold value and the alternative fluid output is provided when the operating pressure of the pump assembly is greater than the predetermined threshold. 
     
     
         25 . The method of  claim 24 , further comprising setting the predetermined threshold value so that during about 80% of the duty cycle the operating pressure does not exceed the predetermined threshold. 
     
     
         26 . The method of  claim 24 , further comprising measuring the operating pressure with a pressure switch. 
     
     
         27 . The method of  claim 26 , wherein said measuring comprises continuously monitoring the operating pressure while the pump assembly is operated. 
     
     
         28 . The method of  claim 22 , wherein the pump assembly is powered by a battery and the battery is charged by solar power. 
     
     
         29 . The method of  claim 28 , further comprising switching between solar power and a backup power source based on the voltage of the battery. 
     
     
         30 . The method of  claim 29 , further comprising switching from the first solar power source to the second power source to charge the battery when sunlight is inadequate to charge the battery. 
     
     
         31 . The method of  claim 30 , further comprising stabilizing voltage provided from the battery to the pump assembly within a predetermined range. 
     
     
         32 . A method of powering a compactor ram of a waste compactor, comprising:
 operating a pump assembly comprising a first pump and a second pump to pressurize a hydraulic cylinder during a duty cycle, the hydraulic cylinder having a piston assembly associated with moving a compactor ram; and   monitoring an operating pressure of the pump assembly,   wherein said operating a pump assembly comprises providing an initial fluid output from the pump assembly when the operating pressure is below a predetermined threshold and providing an alternate fluid output from the pump assembly when the operating pressure is greater than or equal to the predetermined threshold.   
     
     
         33 . The method of  claim 32 , wherein providing the initial fluid output comprises simultaneously operating both pumps, and providing the alternate fluid output comprises operating the first pump but not the second pump. 
     
     
         34 . The method of  claim 33 , wherein said operating of the pump assembly comprises extending the compactor ram until the predetermined pressure threshold is reached then turning off the second pump and continuing to operate the first pump until a maximum pressure is reached, then retracting the compactor ram. 
     
     
         35 . The method of  claim 34 , further comprising setting the predetermined threshold value so that during about 80% of the duty cycle the operating pressure does not exceed the predetermined threshold. 
     
     
         36 . The method of  claim 32 , wherein said monitoring is performed by a pressure switch. 
     
     
         37 . The method of  claim 36 , wherein the operating pressure is continuously monitored while the pump assembly is operated. 
     
     
         38 . A method of powering a compactor ram of a waste compactor, comprising:
 operating a pump assembly comprising a programmable logic controller, a first pump and a second pump to pressurize a hydraulic cylinder during a duty cycle, the hydraulic cylinder having a piston assembly associated with moving a compactor ram; and   monitoring an operating pressure of the pump assembly,   wherein the programmable logic controller directs the pump assembly to provide an initial fluid output when the operating pressure is below a predetermined threshold and provide an alternate fluid output when the operating pressure is greater than or equal to the predetermined threshold.   
     
     
         39 . The method of  claim 38 , wherein the programmable logic controller receives a signal from a pressure switch when the operating pressure crosses the predetermined threshold. 
     
     
         40 . The method of  claim 38 , wherein providing the initial fluid output comprises simultaneously operating both pumps, and providing the alternate fluid output comprises operating the first pump but not the second pump. 
     
     
         41 . The method of  claim 40 , wherein the pump assembly is powered by a battery and the programmable logic controller switches between solar power and a backup power source based on the voltage of a battery.