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Cryomech LNP-10 Standard Operating Procedures Orfeo Colebatch 13 October 2016 Table of Contents: Startup…………………………………………………………………………………………………………………………..2 Shutdown………………………………………………………………………………………………………………………5 Daily checklist..……………..…………………………………………...…………………………………………………6 Maintenance Schedule…………………….…………………….………………………………………..……………7 Specifications……………………………………………………………………………………………………………..…8 Below is an abbreviated Standard Operating Procedure for the Cryomech LNP-10 Liquid Nitrogen Generation plant. This is simply a cut down version of the Cryomech LNP-10 and Quincy QR-25 manuals, for a more complete description please see the above manuals. Important: When the LNP-10 compressors are running you will need to keep the pump room door open to keep temperatures within operating range. The LNP-10 can operate between 7-38 °C. Important: When extracting LN2 from the Cryomech Dewar to fill the Norhof Dewar keep doors to the pump room and lab exterior door open. Nitrogen gas will displace oxygen in the small pump room and the risk of asphyxiation will increase. 1. Startup Note if the dewar is empty you’ll need to purge it with dry nitrogren for 1 hour. If you’ve left the dewar disconnected with Liquid Nitrogen (LN2) inside and the dewar is pressurized (~10 PSIG) then you can partially skip this step. 1. Start Air Dryer a. Close air compressor outlet b. Start dryer and operate for 5 minutes without airflow. Confirm drain hose is inside bottle 2. Air compressor pre-start checklist a. Remove any tools/blockages from pulley & motors. b. Check lubricant levels between Low and High mark. Replace lubricant if contaminated. c. Check pulley alignment is straight and pulley free of nicks and tears. d. Check Pulley tension is between 6.2-8.1 lbs (6.1” diameter motor pulley) when compressed 0.22” (14” span length x 1/64). e. Manually rotate pulley to check there are no mechanical interference f. Check that belt guard is in place and that additional bolt squashing cage is not becoming loose. 3. Start air compressor a. Close air compressor outlet valve b. Jog the air compressor power to check for correct rotation of pulley c. Power on air compressor d. Monitor compressor for excessive noise or vibration. Stop air compressor if either exists and troubleshoot via compressor manual. e. Check system pressure gradually reaches 110 PSIG f. Check manual pressure relief valves on Quincy QR-25 are working g. Drain air compressor of any liquid by opening valve on the bottom of the tank. 4. Purge Filter Bank a. If Liquid Nitrogen exists in the Dewar and the Dewar is pressurized (i.e. dry of moisture) and the Dewar Nitrogen Flex Line is disconnected from the Filter Bank you can purge the Filter bank for 15 minutes. Otherwise proceed to 5. Purge Dewar. b. Slowly open air compressor outlet to pressurize air dryer and filter bank. c. Check for air/nitrogen leaks from the copper tubing and filter bank by squirting Snoop around the join between the copper tubing and Swagelok fitting. Take care not to get any water on the electrical outlets but using a rag as you squirt. d. Check pressure on the filter bank regulator is 85 PSIG. Regulate if it isn’t. e. Purge filter bank for 15 minutes, check that you feel O2 coming out of the O2 vent of the filter bank outside the building. f. Connect Nitrogen Flex line from Dewar into Filter bank. g. Confirm the Dewar pressure increases slowly to 7 PSIG, regulate in small steps if it isn’t (the regulator has a lot of Hysteresis). 5. Purge Dewar a. Skip this step if 4.a) was satisfied (Dewar contains LN2). If Dewar is empty (contains moisture) proceed with this step b. Confirm Nitrogen flex line is connected between Dewar and Filter bank c. Thread purging plug onto Dewar extraction line by hand d. Confirm extraction line is closed e. Slowly open air compressor outlet to pressurize air dryer and filter bank. f. Check for air/nitrogen leaks from the copper tubing and filter bank by squirting Snoop around the join between the copper tubing and Swagelok fitting. Take care not to get any water on the electrical outlets but using a rag as you squirt. g. Check pressure on the filter bank regulator is 85 PSIG. Regulate if it isn’t. h. Check the Dewar pressure increases slowly to 7 PSIG, regulate in small steps if it isn’t (the regulator has a lot of Hysteresis). i. Purge Dewar by opening Dewar extraction line valve. You should feel a flow of gas coming out of the extraction hose. j. Purge in this state for 1 hour with the door to the pump room open. The O2 alarm may trigger. k. Close extraction line l. Remove purge plug. 6. Start Helium Compressor a. Check Low pressure and High Pressure gauges. In a static (off) state they should be 210 PSIG (Low) and 205 PSIG (High). b. Confirm Dewar cord is connected to both Helium Compressor and Dewar c. Make sure Electrical Protection Device is connected to Helium Compressor. d. Make sure all Aeroquip couplings are securely fastened and helium flex lines are oriented correctly (Low to Low and High to High between the Dewar Cold head and Helium compressor) e. Check the dedicated circuit breaker on the Helium compressor is on f. Make sure air dryer is running g. Check Dewar Pressure as 7 PSIG h. Check Filter Bank pressure is 85 PSIG i. Check Automatic Drain Valve (ADV) is operating by pressing manual override switch. Check ADV gives dry air after the 2nd manual override. j. Power on the Helium Compressors circuit breaker. k. The Electrical Protection device should show a yellow light (Power supplied to Electrical Protection device) and green light (LNP-10 has power supplied). If a red light is present then the Electrical Protection device is in a Fault condition. Do not try to operate the Helium compressor. l. Start the Helium Compressor by pressing the green button on the front panel, there may be a 1 minute delay before it turns on. m. IMMEDIATELY check the Low and High pressure gauges on the Helium compressor. They should have a 200 PSIG pressure differential. Low typically measured 70-80 PSIG and High should read 280-285 PSIG. If there is NOT and immediate pressure differential turn off the system. n. Confirm the helium flex lines are correctly orientated. Check the high pressure ports are connected between the Helium compressor and Dewar cold head. Do the same for the Low Pressure ports. 7. Monitor Helium Compressor for normal operation a. Helium compressor should emit a rhythmic squeak or chirp 144 times per minute b. A temperature differential should exist between Aeroquip lines between the Helium compressor and cold head. The High pressure Aeroquip should be at room temperature while the Low pressure line is much warmer after a few minutes. c. The Dewar pressure will drop to 3 PSIG when the Dewar is cooled. d. The black needle on the Dewar LN2 level should not jump around, if it does this is a sign moisture is in the system and the system should be purged. e. The red STANDBY light will illuminate on the dewar once the dewar is full. i. If the system is not running and the dewar standby light is not on there is a malfunction in the system. f. The Dewar pressure relief valve will open at 10 PSIG and frost may accumulate here. i. If the Dewar pressure is greater than 15 PSIG disconnect nitrogen flex line from the low pressure regulator and relieve pressure through bleed valve. Note that pressures greater than 25 PSIG will destroy Dewar pressure gauge. g. Log the amount of time the air compressor remains off. Excessively long “off” periods can be an indication the cold head needs a service. h. Log the items in Daily Checklist daily. Drain the air compressor of water daily. 2. Shutdown We plan to leave the Dewar with Liquid Nitrogen inside the Dewar which will keep the Dewar dry while the LN2 boils off. Attention needs to be paid to check that the Dewar Pressure is not rising above the 10-12 PSIG of the pressure relief valve. Important: If you are shutting the system down with LN2 in the dewar you must disconnect the Nitrogen flex line from the Filter bank. If you fail to do so moisture will leak into the Helium compressor and destroy the CP820 module when you power the system on. If you’ve left the Nitrogen flex line connected to the dewar with the power off to the compressor(s) you’ll need to purge the dewar of moisture. 1. Power off Helium Compressor a. Press power switch on Helium Compressor b. Switch off front panel mounted circuit breaker on Helium compressor c. Switch off dedicated circuit breaker to Helium compressor. 2. Power off Air compressor a. Switch off dedicated circuit breaker for Air Compressor. b. Close air compressor outlet c. Drain air compressor of air and water 3. Disconnect Nitrogen flex line from Filter bank a. Disconnect Nitrogen flex line from filter bank but leave it connected to Dewar. 4. Monitor pressure on Dewar and confirm pressure relief valves are keeping pressure at 1012 PSIG. 5. Power off Air Dryer a. Wait 5 minutes after powering off air compressor and disconnecting pressure and then power off air dryer 3. Daily Checklist Air Compressor Drain Air compressor daily Check Oil level Check oil pressure Filter Bank Filter bank pressure Check water filter indicator (green clean, yellow, red change) Activate manual over ride on automatic drain valve and check line is dry after second activation Visually check sight glass of carbon filter and after filter for signs of moisture Open drain valve on bottom of carbon filter Dewar Check dewar pressure – value should be 3-7 PSIG (operating) , 10-12 PSIG when system is off (static). o If pressures greater than 15 PSIG disconnect nitrogen flex line and open dewar bleed valve Helium Compressor Record Low and High pressure gauges on He compressor Dryer Confirm Power switch on Confirm Dew point indicator is in green zone Check condensate line is draining; empty bottle if level of water is too high. 4. Maintenance Schedule Helium Compressor Periodically check fins of heat exchanger inside LNP-10 side panel and blow dust off. Do this with power to the Helium compressor off. Replace adsorber every 15000 hours (CP800) Filter Bank Replace filter elements every 4 months Air Compressor Weekly /40 hours o Check pressure relief valves are working o Clean cooling surfaces of intercooler o Check for air leaks o Impact coolant for contamination and change if necessary o Clean or replace air intake filter, check frequency increases in humid environments Monthly/160 hours o Check belt tension 3 months/500 hours o Change oil (non Quin-Cip oil) and filter elements o Torque pulley clamp screws or jamnut 6 months/1000 hours o When Quin-Cip lubricant is used oil change can be every 6 months/1000 hours o Inspect compressor valves for leakage and/or carbon build-up. The oil sump strainer screen inside the crankcase of pressure lubricated models should be thoroughly cleaned with a safety solvent during every oil change. If excessive sludge build-up exists inside the crank case, clean the inside of the crankcase as well as the screen. Never use a flammable or toxic solvent for cleaning. Always use a safety solvent and follow the directions provided. 12 months/2000 hours o Inspect the pressure switch diaphragm and contacts. Inspect the contact points in the motor/starter. 5. Specifications Below is a copy of the specifications of the LNP-10. These can be handy for identifying components or specifications/requirements. Section 5 Specifications 5.1-N Specifications Section 5: Specifications 5.1 Intended use of equipment The liquid nitrogen plant is used to produce and store liquid nitrogen. Current clients include research laboratories and universities as well as agricultural facilities. 5.2 Technical specifications Following are the detailed technical specifications for the liquid nitrogen plant. CAUTION Operation of the liquid nitrogen plant in any situation that does not meet the specifications in this section will void the warranty. If you plan to operate the system outside any of the specified conditions, contact Cryomech. 5.2.1 Weights and dimensions Parameter Value Dewar Weight Empty Full Dewar Dimensions (Outside Diameter x H) Dewar Capacity Helium Compressor Package Weight Air-Cooled Water-Cooled Helium Compressor Package Dimensions (L x W x H) Air-Cooled Water-Cooled N2 Generator/Filter Bank Panel Weight N2 Generator/Filter Bank Panel Dimensions (L x W x H) Air Compressor Weight Air Compressor Dimensions (L x W x H) 105 lb 167 lb 48 kg 76 kg 18 ¼ x 32 in 46 x 81 cm 9 gal 35 liters 144 lb 135 lb 65 kg 61 kg 19 x 22 x 22 in 18 x 18 x 22 in 49 x 56 x 56 cm 46 x 46 x 56 cm 59 lb 27 kg 42 x 7 x 29 in 107 x 18 x 74 cm 249 lb 43 x 22 x 39 in 113 kg 109 x 56 x 99 cm 5.2.2 Helium compressor cooling water specifications Parameter Cooling Water: minimum flow @ maximum temperature Maximum Inlet Pressure Alkalinity Calcium Carbonate Value See Figure 5-1 110 PSIG 5.8 < pH < 8.0 Concentration < 80 PPM 5-1 7.6 bar 5.8 < pH < 8.0 Concentration < 80 PPM Specifications Water Flow Rate (LPM) 2.0 2.5 3.0 3.5 4.0 4.5 0 Water Inlet Temperature ( F) 1 80 28 2 0 1.5 24 75 70 20 65 16 60 55 12 50 1 CP810 / CP819 / CP820 45 2 CP830 8 40 Water Inlet Temperature ( C) 1.0 85 4 35 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 Water Flow Rate (GPM) Figure 5-1: Cooling water requirement* Water Pressure Drop (bar) 0.2 0.4 0.6 0.8 1.0 Water Flow Rate (GPM) 1.6 1.2 1 1.4 1.6 2 6 1.4 5 1.2 4 1.0 0.8 3 1 0.6 2 0.4 CP810 / CP819 / CP820 2 CP830 Water Flow Rate (LPM) 0.0 1.8 1 0.2 0 2 4 6 8 10 12 14 16 18 20 22 24 Water Pressure Drop (PSI) Figure 5-2: Cooling water pressure drop* * When using a 50-50% mixture of ethylene glycol and water increase the flow rate 10%. Pressure drop values will increase 40%. 5-2 Specifications 5.2.3 Helium compressor electrical specifications Parameter Nominal voltage Operating voltage range Frequency Phase Water Cooled Input Power Maximum: Steady state: Current Air Cooled Input Power Maximum: Steady state: Current Mains supply voltage fluctuations 208/230 Volt 60 Hz Model 200 Volt 50 Hz Model 208/230 VAC 200 VAC 208 - 230 VAC 200 VAC 60 Hz 1 50 Hz 1 2.2 kW 1.9 kW 2.0 kW 11 A 1.7 kW 9.5 A 2.4 kW 2.1 kW 2.2 kW 11.5 A 1.9 kW 10.5 A Up to ± 10% of the nominal voltage Up to ± 10% of the nominal voltage 5.2.4 Helium compressor fuse specification System Voltage Transformer Fuse* Fuse Rating 200 VAC 208/230 VAC 150 VA Primary 1.5 A *Fuse is 13/32” x 1-1/2”, Type CC time delay fuses, rated for 600V. 30Oct08 5-3 Specifications 5.2.5 Air compressor electrical specifications Parameter Nominal voltage Operating voltage range Frequency Phase Horse Power Current Dedicated circuit breaker Mains supply voltage fluctuations 230 Volt 60 Hz Model 230 Volt 50 Hz Model 230 VAC 230 VAC 207 - 253 VAC 207 - 253 VAC 60 Hz 1 50 Hz 1 2 2 12 A 8.9 A 15 A 15 A Up to ± 10% of the nominal voltage Up to ± 10% of the nominal voltage 5.2.6 Operating parameters Parameter Ambient temperature range* System helium pressure Acceptable location Maximum altitude for use Environment Installation Maximum relative humidity Maximum sound level (air cooled) Maximum sound level (water cooled) Value 45 to 100 °F 7 to 38 °C 200 ± 5 PSIG @ 60 Hz (13.8 ± .34 bar @ 60 Hz) Indoors only 6560 ft Pollution Degree 2 13.8 ± .34 bar @ 50 Hz (200 ± 5 PSIG @ 50 Hz) Indoors only 2000 m Pollution Degree 2 Category II 80% for T< 88°F Decreasing linearly to 50% at 104°F. Category II 80% for T< 31°C Decreasing linearly to 50% at 40°C. 76 dBA at 1 meter 76 dBA at 1 meter 70 dBA at 1 meter 70 dBA at 1 meter *The helium compressor package is designed to operate in an ambient temperature range from 45°F to 100°F (7 to 38°C). If the temperature is below 45°F, the increased viscosity of the oil could prevent start-up and/or cause poor lubrication. Operation above 100°F will cause overheating and subsequent problems. If a unit must be subjected to either extreme, Cryomech must be consulted. 5.2.7 Safety Devices A number of safety switches and valves are located inside the compressor package and on the cold head. They operate automatically to protect the compressor package and cold head from developing extreme conditions that can damage them. Most of them are totally transparent to the user. The ones you need to know about are described below. 5-4 Specifications High-Pressure Atmospheric Relief Valve The compressor package high-pressure atmospheric relief valve is set at 335 ± 5 PSIG (23 ± .34 bar). At pressures above 335 PSIG (23 bar) the relief valve will open automatically and relieve pressure to the atmosphere. External Motor Overload Switch An external motor overload switch, located on the compressor module, protects the system by sensing excessive current draw and temperature. This switch automatically resets itself after the compressor module cools to an acceptable level. Cold Head High Pressure Relief Valve The cold head high-pressure atmospheric relief valve is set at 425 ± 5 PSIG (29.3 ± .34 bar). At pressures above 425 PSIG (29.3 bar) the valve will open automatically and relieve pressure to the atmosphere. 5-5 Specifications 5.3 Description of the helium compressor Power Switch Hour Meter Low Pressure Gauge Low Pressure Aeroquip Dewar Cord Connector High Pressure Gauge High Pressure Aeroquip Circuit Breaker Service Valve Cooling Water Inlet Connection Cooling Water Outlet Connection Service Access Temperature Switch Reset Pressure Switch Reset Power Cord Figure 5-3: Front panel of a water cooled compressor package 5-6 Specifications Power Switch Hour Meter Service Valve Service Access Low Pressure Gauge Circuit Breaker Low Pressure Aeroquip High Pressure Gauge Dewar Cord Connector High Pressure Aeroquip Temperature Switch Reset Power Cord Pressure Switch Reset Figure 5-4: Front panel of an air cooled compressor package 5-7 Specifications 5.3.1 Front panel interfaces This section describes the function of all operator interfaces on the front panel of the CP800 Series Compressor Package, including switches and valves. It also describes the functions of all connectors, electrical cords and gauges on the front panel. Low-Pressure Aeroquip® The low-pressure helium flex line (not shown) fastens to the low-pressure Aeroquip® that returns helium gas from the cold head to the compressor package. Low-Pressure Gauge The low pressure gauge displays the pressure of the helium gas that is being returned to the compressor package. When the compressor package is off and the complete system is at room temperature, the gauge should read the pressure specified in Section 5.2. High-Pressure Aeroquip® The high-pressure helium flex line (not shown) attaches to the high-pressure Aeroquip® that supplies compressed helium gas from the compressor package to the cold head. High-Pressure Gauge The high-pressure gauge displays the pressure of the compressed helium gas that is transported from the compressor package. When the compressor package is off and the complete system is at room temperature, the gauge should read the pressure specified in Section 5.2. Hour Meter The hour meter is an elapsed time indicator located on the front panel near the power switch. The hour meter is used to keep track of times for routine servicing and part replacement, which are determined by the number of hours of active use. Power Switch The lighted, push button, power switch activates (starts) the entire system. Dewar Cord Connector The dewar cord attaches to the dewar cord connectors on the compressor and the dewar. The dewar cord provides power from the compressor package to the level indicator/switch and cold head motor. Circuit Breaker The front panel-mounted circuit breaker provides over-current protection for the cryorefrigerator and functions as a main power disconnect. Service Valve The service valve is the valve used to regulate the amount of helium being added to or released from the system. Service Access The service access is used in conjunction with the service valve for adding helium to or releasing helium from the system. 5-8 Specifications Cooling Water Inlet Connection The cooling water inlet connection provides water to the compressor package from your facility to cool the compressor package during operation. The connector thread size is 1/4 FPT (1/4” Female National Pipe Thread). The water must meet the specifications provided in the Cooling Water Specifications table in Section 5.2. Cooling Water Outlet Connection The cooling water outlet connection carries heated water away from the compressor package after the water has been heated by cooling the compressor package during operation. The connector thread size is 1/4 FPT (1/4” Female National Pipe Thread). Pressure Switch Reset (Low Pressure) The compressor package has a low-pressure shutdown switch that is set at 35 ± 5 PSIG (2.4 ± .34 bar). The pressure switch manual reset button is located on the bottom of the front panel as shown in Figure 5-3 or 5-4. Temperature Switch Reset (High Temperature) The high temperature shutdown switch is set at 120°F (49°C) for water cooled units and 130°F (54°C) for air cooled units. The high temperature manual reset button is located on the bottom of the front panel as shown in Figure 5-3 or 5-4. The temperature switch cannot be reset until the sensor has cooled by approximately 15°F (8.5°C). Power Cord The power cord supplies power from the wall to the entire system. 5-9 Specifications 5.4 Description of the dewar The dewar is a stainless steel, vacuum jacketed container built for the purpose of storing liquid nitrogen with minimal boil off. The dewar is sealed from the atmosphere so that only nitrogen flowing from the nitrogen generator can enter it. Attached to the dewar are the cold head, low pressure regulator, level indicator/switch, pressure relief valves, burst disk, bleed valve and extraction line. Pressure Gauge N2 Inlet Coupling Low Pressure Regulator Dewar Extraction Line Valve Cold Head Level Indicator/Switch Bleed Valve Standby Light Pressure Relief Valve Primary Dewar Cord Receptacle Burst Disc Pressure Relief ValveSecondary Extraction Line Figure 5-5: Front view of the dewar (representative model) Figure 5-6: Rear view of the dewar (representative model) Cold Head The cold head is attached to the top of the dewar with four bolts. An O-ring, located between the dewar flange and the cold head, seals the nitrogen gas inside the dewar. Low Pressure Regulator A low pressure regulator is attached to the top of the dewar. The regulator is set to maintain a pressure inside the dewar of 3-7 PSI (0.2-0.5 bar) above atmospheric pressure. Pressure Gauge The pressure gauge attached to the low pressure regulator displays the gaseous nitrogen pressure inside the dewar. 5-10 Specifications N2 Inlet Coupling The quick connect coupling attached to the regulator is the inlet port for the gaseous nitrogen. The flexible, stainless steel nitrogen line (not shown) attaches to the N2 inlet coupling. Level Indicator/Switch The level indicator/switch monitors and regulates the amount of liquid nitrogen in the dewar. The level indicator/switch is preset to shut down the system when the dewar is full. The user can set the liquid nitrogen level, at which the system will automatically restart. Standby Light The standby light will illuminate when the level indicator/switch has shut the system down. Dewar Cord Receptacle Power is supplied to the level indicator/switch by the dewar cord that connects to the dewar cord receptacle on the dewar and the helium compressor package. The liquid nitrogen plant will not operate unless the dewar cord is connected to the dewar and the helium compressor. Bleed Valve The bleed valve is used to release the pressure inside the dewar. Pressure Relief Valves The primary pressure relief valve will begin to open when the pressure inside the dewar is approximately 10 PSIG. A secondary 15 PSIG pressure relief valve will activate if the primary relief valve fails to open. Burst Disc The burst disk is an additional safety feature that protects the dewar if both relief valves fail. The burst disk activates at approximately 50 PSIG. Extraction Line Liquid nitrogen is extracted from the dewar by opening the extraction line valve attached to the vacuum jacketed extraction line. The extraction line connects to an internal tube that extends to the bottom of the dewar. The positive pressure inside the dewar pushes the liquid nitrogen out of the dewar. 5-11 Specifications 5.5 Description of the N2 generator/filter bank panel The N2 (nitrogen) generator/filter bank panel consists of a pressure regulator, a series of compressed air filters, a dehumidifier, and a N2 generator, all attached to a wall mountable panel. The compressed air filters are necessary to remove particulates, moisture and oil from the compressed air supply before it enters the nitrogen generator. The optional dehumidifier removes vaporous moisture from the compressed air stream before entering the carbon filter. The N2 generator produces 98% pure nitrogen gas from the compressed air supply. After Filter Carbon Filter Dehumidifier Coalescing Filter Wall Mountable Panel Water Filter Pressure Gauge N2 Outlet Coupling Needle Valve N2 Generator Compressed Air Inlet Port N2 Generator Vent High Pressure Regulator Check Valve Sight Glass (typical) Manual Drain Valve Automatic Drain Valve (ADV) Figure 5-7: N2 generator/ filter bank panel (representative model) High Pressure Regulator The high pressure regulator is preset and locked at 85 PSIG (5.9 bar). This compressed air pressure setting is required for optimal performance of the N2 generator. Pressure Gauge The pressure gauge, attached to the high pressure regulator, indicates the compressed air pressure in the filter bank. Needle Valve (optional) A needle valve, attached to the inlet of the high pressure regulator, is supplied if the system is fitted with the optional dehumidifier. The needle valve protects the dehumidifier from rapid pressurization that may rupture it. 5-12 Specifications Compressed Air Inlet Port The compressed air inlet port is a 3/8” compression fitting attached to the needle valve, if supplied, or the high pressure regulator. The compressed air inlet supply connects to this fitting. Water Filter The water filter removes condensed moisture and particulate matter from the compressed air supply. The trapped moisture drips to the bottom of the filter bowl and is expelled through the automatic drain valve. The filter is fitted with a visual indicator to monitor the condition of the filter element. The filter element is replaceable. Coalescing Filter The coalescing filter is designed to remove oil from the compressed air supply. It is also capable of removing small amounts of condensed moisture. The trapped oil and moisture drips to the bottom of the filter bowl, passes through the check valve and is expelled through the automatic drain valve. The filter element is replaceable. Automatic Drain Valve The automatic drain valve (ADV) expels the moisture and oil collected in the water and coalescing filter bowls. The drain valve is controlled by an electronic timer that allows the user to set the frequency and duration of the valve’s opening. Dehumidifier (optional) The dehumidifier is designed to remove water vapor from the compressed air before it enters the carbon filter. The dehumidifier consists of bundles of hollow membrane fibers, each permeable only to water vapor. As the compressed air passes through the center of these fibers, water vapor permeates through the walls of the fiber, and dry air exits from the other end of the fiber. The dehumidifier maintains a constant “sweep” flow to carry water vapor laden air away from the end of the membrane module. This sweep flow will result in a constant “hiss” of air from the inlet end of the dehumidifier. Carbon Filter The carbon filter contains an activated carbon element to further eliminate any hydrocarbon contaminants in aerosol form from the compressed air supply. The filter is not designed to remove moisture. The filter element is replaceable. Manual Drain Valve The carbon filter is equipped with a manual drain valve to check for any condensed moisture that may have accumulated in the filter bowl. Any evidence of moisture indicates a problem with either the compressed air supply or the preceding filters. Sight Glass Each filter is fitted with a sight glass to monitor any accumulation of moisture in the filter bowl. After Filter The afterfilter catches any carbon dust that may migrate from the carbon filter and damage the N2 generator. The filter is not designed to remove moisture. The filter element is replaceable. 5-13 Specifications N2 (Nitrogen) Generator The N2 generator uses membrane technology to produce 98% pure nitrogen gas from compressed air. Nitrogen passes through the membrane while the other constituents of air are separated out and returned to the atmosphere through the nitrogen generator’s vent. The nitrogen generator can withstand water vapor in the compressed air supply; however liquid water, oil, and carbon dust will destroy it. N2 Outlet Coupling The quick connect coupling attached to the N2 generator is the outlet port for the gaseous nitrogen. The flexible, stainless steel nitrogen line (not shown) attaches to the N2 outlet coupling. 5-14 Specifications 5.6 Description of the air compressor The standard air compressor, if supplied by Cryomech, is a two stage, pressure lubricated compressor with a horizontal receiving tank. The air compressor supplies the N2 generator/filter bank panel with the required compressed air flow rate and pressure necessary to produce 98% pure nitrogen gas. Inlet Air Filter Oil Pressure Gauge Belt Guard Electric Motor Oil Filter Motor Overload Reset Button Receiver/Tank Pressure Gauge Pressure Switch Compressed Air Outlet Valve Power Cord Compressed Air Outlet Port Receiver/Tank Drain Valve Figure 5-8: Air compressor (representative model) Power Cord The power cord supplies power from the wall to the electric motor. Pressure Switch The pressure switch automatically starts and stops the air compressor to maintain the required air pressure supplied to the N2 generator/filter bank panel. The pressure switch is preset and does not require adjustment. Motor Overload Reset Button The motor overload reset button is used to restart the air compressor if the motor overload trips. The motor overload is preset and does not require adjustment. 5-15 Specifications Inlet Air Filter The inlet air filter removes dust and particulates from the ambient air before it enters the air compressor’s compression chamber. The filter element is replaceable. Oil Pressure Gauge The oil pressure gauge displays the pressure in the air compressor’s oil lubrication circuit. Oil Filter The oil filter traps contaminants in the air compressor’s lubrication oil. The filter is replaceable. Not all compressors are fitted with oil filters. Receiver/Tank Pressure Gauge The receiver/tank pressure gauge displays the compressed air outlet pressure. Compressed Air Outlet Valve The compressed air outlet valve, when open, allows the compressed air to exit the receiver/tank. Compressed Air Outlet Port The compressed air outlet port is a 3/8” compression fitting that is used to connect the air compressor to the high pressure regulator on the N2 generator/filter bank panel. The connection is made with the copper tubing supplied with the air compressor. Receiver/Tank Drain Valve The receiver/tank drain valve is used to drain moisture collected in the receiver. 5-16 Specifications 5.7 Description of the refrigerated air dryer (option) The optional refrigerated air dryer removes moisture from the compressed air stream before it enters the N2 generator/filter bank panel. The dryer operates automatically and requires periodic maintenance. The manufacturer’s user manual is included with the dryer. Power Switch Dewpoint Indicator Condensate Drain Line Figure 5-9: Refrigerated air dryer – front view Inlet Air Port Power Cord Outlet Air Port Figure 5-10: Refrigerated air dryer – rear view Power Switch The power switch will start and stop the dryer. The power switch is equipped with a light that will illuminate when the switch is on. 5-17 Specifications Dewpoint Indicator The dewpoint indicator provides a visual indicator of the compressed air’s dew point. Condensate Drain Line The condensate drain line is a plastic tube that carries away the moisture removed from the compressed air. Inlet Air Port The inlet air port is a 3/8” compression fitting that is used to connect to the outlet port of the air compressor. The connection is made with the copper tubing supplied with the air compressor. Outlet Air Port The outlet air port is a 3/8” compression fitting that is used to connect to the inlet port of the N2 generator/filter bank panel. The connection is made with the copper tubing supplied with the dryer. Power Cord The power cord supplies electrical power from the wall to the dryer. 5-18 Specifications 5.8 Description of the electrical protection device (option) The optional electrical protection device (EPD) monitors the supply voltage for phase loss as well as for overvoltage and undervoltage conditions. If one of the fault conditions occurs, the EPD disconnects the power to the entire system. The EPD is housed in a wall mountable electrical enclosure. The enclosure is fitted with an input power cord and three indicator lights to display the status of the device. Yellow Indicator Light Green Indicator Light Red Indicator Light Enclosure Power Cord Fuse Block Fuse Cover with Indicator Light Monitoring Relay Figure 5-11: Electrical protection device Yellow Indicator Light The yellow light indicates that power has been supplied to the electrical protection device. Green Indicator Light The green light indicates that the LNP is being supplied with power. Red Indicator Light The red light indicates that the protection device is in a fault condition. Power Cord The power cord is fitted with a 5 pin connector that attaches to a mating receptacle located on the front panel of the helium compressor package. Monitoring Relay The monitoring relay ensures that the voltage supply to the helium compressor is within its acceptable limits. If a fault condition occurs the output relay is de-energized, shutting down the LNP. See the next section for detailed information of the monitoring relay. 5-19 Specifications Fuse Block The fuse block is fitted with two fuses to protect the monitoring relay. Fuse Cover with Indicator Light A fuse cover with indicator light is fitted over each fuse. The indicator lights are illuminated only when a fuse is blown. Two spare fuses are shipped with the system inside the enclosure. 5.8.1 Description of the monitoring relay The monitoring relay ensures that the voltage supply to the helium compressor is within its acceptable limits. If a fault condition occurs the output relay is de-energized, shutting down the LNP. The monitoring relay has been preset at the factory and requires no adjustment. The monitoring relay uses five LED’s to indicate its status. When a fault condition occurs, it triggers an internal timer that monitors the fault condition for 5 seconds. If the fault condition is still present after the 5 second interval, the monitoring relay shuts down the LNP. When the monitoring relay trips, the green indicator light on the EPD will turn off and the red indicator light will illuminate. In addition, the fault condition is indicated by an LED on the monitoring relay. When the fault condition is corrected, the monitoring relay will close and restart the LNP immediately. The EPD’s red indicator light will turn off and the green indicator light will illuminate. If a power outage occurs, the system will restart automatically when the power returns and the one minute time delay built into the LNP has elapsed. Overvoltage Indicator (>U) Relay Indicator (R) Undervoltage Indicator (<U) Power Indicator (U) Phase Loss Indicator (P) Figure 5-12: Monitoring relay in normal operation mode 5-20 Specifications Power Indicator (U) The power indicator is a green LED. It illuminates whenever the monitoring relay is supplied with power. Relay Indicator (R) The relay indicator is a green LED. It illuminates when the monitoring relay is closed and power is being supplied to the LNP. When a fault condition occurs, the relay opens and the LED is not illuminated. Overvoltage Indicator (>U) The overvoltage indicator is a red LED. It illuminates when an overvoltage condition occurs. Undervoltage Indicator (<U) The undervoltage indicator is a red LED. It illuminates when an undervoltage condition occurs. Phase Loss Indicator (P) The phase loss indicator is a red LED. It illuminates when a phase loss condition occurs. Relay Indicator (R) Undervoltage Indicator (<U) Power Indicator (U) Figure 5-13: Monitoring relay in undervoltage fault condition When in a fault condition, the Relay Indicator (R) LED is not illuminated and the LED corresponding to the fault condition is illuminated. The Power Indicator (U) LED remains illuminated throughout the fault condition. Specifications