Apparatus and method of backflow prevention

Abstract

A backflow preventer apparatus comprising an inline solenoid valve configured to shut when de-energized, disposed between a closed system desired to be evacuated and a vacuum pump, wherein the inline solenoid valve and vacuum pump share a common source of electrical power.

What is claimed is: 
     
         1 . An apparatus for preventing backflow during the evacuation of a refrigeration system, comprising:
 a vacuum pump having a suction connection end and a discharge end configured to discharge to an atmosphere;   a solenoid valve having a solenoid valve end and a solenoid electrical end, wherein the solenoid valve end is operably connected to the suction connection end of the vacuum pump and is operably connected by a first hose to a refrigeration system desired to be evacuated, and wherein the solenoid valve is normally shut and energized open when electrical power is supplied to the solenoid electrical end; and   an electrical power source operably connected to the vacuum pump and solenoid electrical end, wherein a loss of electrical power at the electrical power source or an interruption of electrical power to the vacuum pump and solenoid electrical end thereby results in the shutting of the solenoid valve and securing of the vacuum pump thereby preventing backflow from the atmosphere and the vacuum pump into the refrigeration system.   
     
     
         2 . The apparatus of  claim 1 , wherein the first hose is connected to the refrigeration system via a service port. 
     
     
         3 . The apparatus of  claim 2 , further comprising an alarm operably connected to the electrical power source and configured to alarm during a loss or interruption of electrical power to the solenoid electrical end and vacuum pump. 
     
     
         4 . The apparatus of  claim 3 , further comprising a switch disposed between the electrical power source and the vacuum pump, wherein the switch is configured to open on loss of electrical power and requires manual action to shut thereby preventing inadvertent re-starting of the vacuum pump. 
     
     
         5 . A backflow preventer apparatus, comprising:
 a vacuum pump having a suction connection end and a discharge end;   a solenoid valve having a solenoid valve end and a solenoid electrical end, wherein the solenoid valve end is operably connected to the suction connection end of the vacuum pump, and wherein the solenoid valve is normally shut and energized open when electrical power is supplied to the solenoid electrical end;   at least one electrical power source operably connected to the vacuum pump and solenoid electrical end;   a relay configured to selectably interrupt electrical power to the solenoid electrical end, wherein the relay is responsive to an operating condition of the vacuum pump; and   a first hose operably connecting the solenoid valve end to a refrigeration system wherein when the solenoid valve is closed, backflow from the refrigeration system is prevented.   
     
     
         6 . The backflow preventer apparatus of  claim 5 , wherein the at least one electrical power source is a single electrical power source common to the solenoid valve and vacuum pump. 
     
     
         7 . The backflow preventer apparatus of  claim 6 , wherein the first hose is connected to the refrigeration system via a service port. 
     
     
         8 . The backflow preventer apparatus of  claim 7 , wherein the first hose is a 0.25 inch charging hose rated for 800 psi working pressure and 4,000 psi burst pressure. 
     
     
         9 . The backflow preventer apparatus of  claim 7 , wherein the relay is responsive to a loss of electrical power to the vacuum pump to thereby interrupt electrical power to the solenoid electrical end. 
     
     
         10 . The backflow preventer apparatus of  claim 9  wherein the relay is configured to interrupt electrical power to the solenoid electrical end before all power is lost to the vacuum pump. 
     
     
         11 . The backflow preventer apparatus of  claim 7 , wherein the relay is responsive to a suction pressure of the vacuum pump failing to meet a predetermined threshold. 
     
     
         12 . The backflow preventer apparatus of  claim 7 , wherein the relay is responsive to a differential pressure across the vacuum pump failing to meet a predetermined threshold. 
     
     
         13 . The backflow preventer apparatus of  claim 7 , further comprising a switch configured to open on loss of electrical power and requiring manual action to shut. 
     
     
         14 . The backflow preventer apparatus of  claim 5 , wherein the at least one electrical power source comprises two independent electrical power sources, with a first electrical power source supplying electrical power to the vacuum pump and a second electrical power source supplying electrical power to the solenoid electrical end. 
     
     
         15 . The backflow preventer apparatus of  claim 5 , wherein a pressure gage is attached at least at one of between the refrigeration system and the solenoid valve, on a service connection of the refrigeration system, or to the suction end or discharge end of the vacuum pump. 
     
     
         16 . The backflow preventer apparatus of  claim 5 , further comprising a differential pressure gage operably connected to measure pressure across at least one of the solenoid valve or the vacuum pump. 
     
     
         17 . The backflow preventer apparatus of  claim 5 , wherein the evacuation end of the vacuum pump discharges to at least one of an atmosphere or a storage device. 
     
     
         18 . A backflow preventer apparatus, comprising:
 a vacuum pump, having a first side of a mechanical end of a solenoid valve integrally connected to a suction manifold of the vacuum pump and an electrical end of the solenoid valve connected to an integrated electrical power source, wherein the integrated electrical power source supplies power to the vacuum pump and the electrical end of the solenoid valve, and wherein the solenoid valve is normally shut and energized open when electrical power is supplied to the solenoid electrical end;   a first pneumatic hose having a first end operably connected to a second side of the mechanical end of the solenoid valve and a second end operably connected to a service port of a refrigeration system;   a switch, connected between the integrated electrical power source and the vacuum pump and the solenoid valve, configured to open on a loss of power and require manual shutting following restoration of power.   
     
     
         19 . The backflow preventer apparatus of  claim 18 , further comprising a differential pressure gage operably connected to measure pressure across the integrally connected mechanical end of the solenoid valve and the vacuum pump. 
     
     
         20 . The backflow preventer apparatus of  claim 18 , wherein the vacuum pump further comprises an evacuation end which discharges to at least one of an atmosphere or a storage device.