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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