Purgers and Non-condensables “What are they and why should I care?” Refrigerating Specialties Division Parker Hannifin Corporation July 2004

Non-Condensables AirAir Breakdown of oil/lubricantsBreakdown of oil/lubricants Breakdown of refrigerantBreakdown of refrigerant Refrigerant impuritiesRefrigerant impurities

Why Worry? Non-condensables cause:Non-condensables cause: Higher pressures which in turn… Increase compressor power costs Increase wear & tear on equipment Increase leaks Reduce system efficiency

How? Non-condensables get in a system via:Non-condensables get in a system via: Inadequate system evacuation before chargingInadequate system evacuation before charging Opening system for repair and/or maintenanceOpening system for repair and/or maintenance System leaks (especially less than 0 psig)System leaks (especially less than 0 psig) Refrigerant impuritiesRefrigerant impurities Breakdown of refrigerant or lubricating oilsBreakdown of refrigerant or lubricating oils

Managing Non-condensables (NC’s) Manual purgingManual purging Automatic purgingAutomatic purging

Manual purging is expensive & troublesome.Manual purging is expensive & troublesome. Too much refrigerant gas gets lost to atmosphere.Too much refrigerant gas gets lost to atmosphere. Manual purging also :Manual purging also : Takes time and manpower.Takes time and manpower. Cannot completely eliminate air.Cannot completely eliminate air. Refrigerant gas escapes.Refrigerant gas escapes. Might not comply with local legislationMight not comply with local legislation Easily neglected until air in the systems causes problemsEasily neglected until air in the systems causes problems Manual Purging

Automatic Purger Automatic Purgers automatically remove non-condensable’s like air, which reduce the efficiency of the refrigeration system. Automatic Purgers automatically remove non-condensable’s like air, which reduce the efficiency of the refrigeration system. It eliminates the problems of manual purging listed on the previous page. It eliminates the problems of manual purging listed on the previous page.

Automatic Purger Capable of handling several “Purge Points”Capable of handling several “Purge Points” Most common purge points:Most common purge points: Condenser drainCondenser drain Pilot ReceiversPilot Receivers Thermosyphon ReceiversThermosyphon Receivers High Pressure ReceiversHigh Pressure Receivers “Liquid Drain Header” highest point“Liquid Drain Header” highest point “Equalizing Lines” high point“Equalizing Lines” high point Generally, quiet (low velocity), high side areasGenerally, quiet (low velocity), high side areas

Purger Functions Device to condense the condensables (refrigerant) out of C & NC mix (foul gas) Device to condense the condensables (refrigerant) out of C & NC mix (foul gas) Separation and collection point for non- condensables Separation and collection point for non- condensables Removal system (bubbler) Removal system (bubbler) Controller Controller

Parker’s “Rapid Purger”

Rapid-Purger Key Component Function LIQUID MAKE-UP SOLENOID “Heat Exchanger” Condenses refrigerant gas in the foul gas mixture “Heat Exchanger” Condenses refrigerant gas in the foul gas mixture “Vapor Vent Float” accumulates non-condensables & separates liquid refrigerant “Vapor Vent Float” accumulates non-condensables & separates liquid refrigerant “Pressure Switch” detects non- condensables in Vapor Vent Float “Pressure Switch” detects non- condensables in Vapor Vent Float “Temperature Controller” ensures adequate HX temp. prior to purging “Temperature Controller” ensures adequate HX temp. prior to purging “Foul Gas Vent Solenoid” Opens when pressure in Vapor Vent Float reaches Pressure Switch Set-point “Foul Gas Vent Solenoid” Opens when pressure in Vapor Vent Float reaches Pressure Switch Set-point “Water Bubbler” Absorb Residual Ammonia in Non-condensables “Water Bubbler” Absorb Residual Ammonia in Non-condensables “Liquid Drainer” removes liquid from the Foul Gas supply to the Purger “Liquid Drainer” removes liquid from the Foul Gas supply to the Purger “Pressure Check Valve” Maintains a 30# (L.T.) 50# (H.T.) differential between shell side & tube side “Pressure Check Valve” Maintains a 30# (L.T.) 50# (H.T.) differential between shell side & tube side “LL” float switch controls heat exchanger (HX) liquid level “LL” float switch controls heat exchanger (HX) liquid level “Liquid Make-up Solenoid” Works in conjunction with LL to maintain proper refrig level in HX “Liquid Make-up Solenoid” Works in conjunction with LL to maintain proper refrig level in HX “A2A” used to control HX temp (L.T. only) “A2A” used to control HX temp (L.T. only)

The Rapid Purge Cycle (Pre Purge Check List) Before the Rapid Purger is ready for service, all of the piping and electrical connections must be properly made Before the Rapid Purger is ready for service, all of the piping and electrical connections must be properly made The Rapid Purger must also be active in the system. This means liquid refrigerant must be at the controlled level and temperature in the Heat Exchanger The Rapid Purger must also be active in the system. This means liquid refrigerant must be at the controlled level and temperature in the Heat Exchanger (Low Temp. Only) (Low Temp. Only) Temp/pressure is controlled by an A2A installed in the suction line from the Heat Exchanger to the house suction Temp/pressure is controlled by an A2A installed in the suction line from the Heat Exchanger to the house suction

The Rapid Purge Cycle (Pre Purge Check List) Liquid Make Up to the Heat Exchanger is controlled by the LL float switch. As refrigerant boils off in the Heat Exchanger, the level in the LL tank will drop. This will trip the Float Switch, closing the “Normally Closed” contacts and energizing the S6N in the Liquid Supply Line (circled in red) Liquid Make Up to the Heat Exchanger is controlled by the LL float switch. As refrigerant boils off in the Heat Exchanger, the level in the LL tank will drop. This will trip the Float Switch, closing the “Normally Closed” contacts and energizing the S6N in the Liquid Supply Line (circled in red) As the level in the Heat Exchanger and the LL tank rise, the Float Switch will trip, opening the “Normally Closed” contacts and de- energizing the S6N As the level in the Heat Exchanger and the LL tank rise, the Float Switch will trip, opening the “Normally Closed” contacts and de- energizing the S6N Liquid Supply Line Float Switch

Purge Cycle  The Purge cycle begins when either:  a Central Management System  the R/S Rapid Purger Microprocessor  or the R/S Mini Micro selects one of the pre-programmed purge points  At that time, the Purge Solenoid will be Energized allowing Gas to flow to the Purger Foul Gas Inlet Purge Point Solenoids Liquid

Purge Cycle With hand valve #1 open, Foul gas will flow through the “Liquid Drainer”. With hand valve #1 open, Foul gas will flow through the “Liquid Drainer”. Any liquid ammonia will be separated and returned to the plant suction via the drain line Any liquid ammonia will be separated and returned to the plant suction via the drain line 1/2” Globe Hand Valve #1 Purge Line Drain Line to House Suction

Purge Cycle Gas will flow through Disc Strainer #1, CK4A #1 and Orifice #1 into the Heat Exchanger Gas will flow through Disc Strainer #1, CK4A #1 and Orifice #1 into the Heat Exchanger

Purge Cycle Refrigerant in the Foul Gas entering the Heat Exchanger will condense immediately Refrigerant in the Foul Gas entering the Heat Exchanger will condense immediately

Purge Cycle Condensed Refrigerant (liquid) then rises into the Vapor Vent Float Condensed Refrigerant (liquid) then rises into the Vapor Vent Float As the liquid rises, it blocks an orifice (circled in red) allowing pressure to build (due to continued flow of high pressure foul gas entering the HX) As the liquid rises, it blocks an orifice (circled in red) allowing pressure to build (due to continued flow of high pressure foul gas entering the HX) Float Orifice

Purge Cycle Once the pressure exceeds the Pressure Check Valve. (30#Low Temp or 50#High Temp) Once the pressure exceeds the Pressure Check Valve. (30#Low Temp or 50#High Temp) The differential between the shell side & tube side of the HX The differential between the shell side & tube side of the HX The refrigerant then flows through the Pressure Check Valve and orifice # 4, into the “pure liquid” supply, through the tube side of the HX (refrigeration side) and returned to the system The refrigerant then flows through the Pressure Check Valve and orifice # 4, into the “pure liquid” supply, through the tube side of the HX (refrigeration side) and returned to the system

Purge Cycle As the refrigerant level drops, the float (1) will fall, opening the Vapor Vent Float orifice up to the (2) S6N Vent Solenoid. As the refrigerant level drops, the float (1) will fall, opening the Vapor Vent Float orifice up to the (2) S6N Vent Solenoid. Non-condensables will continue to accumulate, producing an elevated pressure Non-condensables will continue to accumulate, producing an elevated pressure 1 2

Purge Cycle Once the pressure (1) of the Non-condensables exceeds the set-point of the Pressure Switch, the (2) S6N Vent Solenoid and the (3) Water Supply Solenoid to the “Water Bubbler” will open Once the pressure (1) of the Non-condensables exceeds the set-point of the Pressure Switch, the (2) S6N Vent Solenoid and the (3) Water Supply Solenoid to the “Water Bubbler” will open Foul Gas Vent Line 1 2 3

Purge Cycle Note: Note: As an additional safeguard, a Temperature Controller and Sensor (circled in red) is wired in series with the Pressure Switch (circled in blue). This prevents venting of non-condensed ammonia to the Water Bubbler before the Heat Exchanger reaches temperature Temperature Controller Sensor Foul Gas Vent Line Pressure Switch

Purge Cycle Non-condensables will then flow through the S6N, CK4A #3, Orifice #3 and the vent line into the Water Bubbler to absorb any residual ammonia Non-condensables will then flow through the S6N, CK4A #3, Orifice #3 and the vent line into the Water Bubbler to absorb any residual ammonia

Purge Cycle As the water in the Bubbler rises, it will overflow the drain tube and exit the drain line As the water in the Bubbler rises, it will overflow the drain tube and exit the drain line

Purge Cycle Once the vent line pressure drops below the Pressure Switch set point, the Vent Solenoid and the Water Supply Solenoid will close Once the vent line pressure drops below the Pressure Switch set point, the Vent Solenoid and the Water Supply Solenoid will close This ends the Purge Cycle. This ends the Purge Cycle.

High Efficiency Heat Exchanger with 2.6 S.F. of condensing surface. Installation at lowest plant suction not req for effectiveness High Efficiency Heat Exchanger with 2.6 S.F. of condensing surface. Installation at lowest plant suction not req for effectiveness Stainless Steel Air Tight Insulated Enclosure Stainless Steel Air Tight Insulated Enclosure Easy to Service Easy to Service Stainless Steel Piping and Components Stainless Steel Piping and Components 2 Microprocessor Controller Options 2 Microprocessor Controller Options F e a t u r e s

F e a t u r e s “Mini Micro” “Mini Micro” 1 to 8 Purge Points 1 to 8 Purge Points Meter for logging Combined Purge Duration Meter for logging Combined Purge Duration “Full Microprocessor” “Full Microprocessor” Up to 48 Purge Points! Up to 48 Purge Points! System Status Screen. LCD Display and Keypad Control for Input and System Monitoring System Status Screen. LCD Display and Keypad Control for Input and System Monitoring Auto Detect System Auto Detect System Password Access Password Access Remote Alarm Option Remote Alarm Option NEMA 4 Enclosure NEMA 4 Enclosure Opt. Cond. Control & Remote Monitoring. Opt. Cond. Control & Remote Monitoring.

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