Sumitomo SRDK Series User manual

He-Compressor and Cold-Head Service
The AMI magnet (6T) in Osujilab is cryo-cooled by continuous Helium supply by a Sumitomo Compressor
operating at a pressure of ~2.2 MPa. The superconductor in the magnet is cryo-cooled by a cold-head
(Sumitomo Inc.) attached to the magnet. Continuous Helium supply is necessary to maintain the
superconductivity in the system. There are two flux lines (supply and return), 6m long connecting the
He-compressor and the cold-head. The flux lines, cold-head and the compressor have self-locks to
isolate them to avoid contamination. When flux lines are disassembled from the cold-head or He-
compressor the locks will automatically be locked. When the pressure in the He-compressor goes below
1.6 MPa, the compressor should be re-filled with Helium (UHP-300, 99.999% purity). Please follow the
instructions before start refilling the He-compressor. If the He-compressor or flux lines are
contaminated, the pressure reading in the He-compressor will drop (usually it will be zero), also when
the He-gas leaks out of the system. Once the system is contaminated, it is advised to get in touch with
Sumitomo Inc. to do a cleaning service.
Figure1: (a) Zero pressure reading due to contamination of the system. In this case the He-gas was escaped through
accidently loosened screws (b). During operation the pressure reading is about 2-2.2 MPa. However, when the He-
compressor or is switched off, the pressure reading is non-zero (~1.6MPa). If the compressor pressure reads zero, it
would not re-start.
Chilled-water supply is connected to the He-compressor to dissipate the heat from the return supply.
When the temperature of the chilled-water supply rises, the He-compressor might shuts down
automatically, and subsequently the magnet temperature will rise. Sometimes, the main power-supply
switch at the back panel will turn off by itself. Then it has to be turned back on as shown in Figure 2.
Most often, switching OFF the drive switch and turning back ON will resume the He-compressor.

Figure2: (a) The main power switch is at the back-panel of the compressor is turned off. To turn it on, rotate the
black switch by 90 deg (ref Figure 6). (b) Front panel switch and the operating hours of the He-compressor.
40088.7h are elapsed as shown in the front panel reading. The maximum operating hours of the instrument
without maintenance is 30,000h. After that the regular service of the He-compressor is recommended-especially
adsorber has to be replaced.
There are two ways to do service on He-compressor and cold-head servicing if the Cold-head or the He-compressor
is contaminated or needs a service. If the compressor/cold-head parts are performing well and only if the parts are
exposed to air, Sumitomo can do an onsite service. Also they can do the adsorber replacement. However if the
motor capsule needs a replacement, then most likely the instrument has to go to the Sumitomo Chicago facility for
service (but check with Roy Roub if they can replace the capsule also by an onsite service). Sumitomo can send a
reconditioned and qualified end/displacer assembly upon request (contact Roy Roub for pricing). Prior
to reconnecting flux lines and the He-compressor, make sure those parts are clean and not
contaminated and also filled with Helium gas (99.999% purity). Please check the price quote prior to
sending the parts to Sumitomo and making an onsite service (onsite service is pricy but faster).
Note: If the cold head or flux line is contaminated (or exposed to air) as judged by the pressure
reading at the He-compressor, the compressor should not be switched on. Contact Roy Roub at
Sumitomo Inc. to proceed further with the repair/service. The cold-head can be removed from the
magnet and can be send out for repair (special care should be taken to release the excess He-gas
residing inside the cold-head prior to unscrewing the 4 screws as shown in the Figure3, for that
appropriate fittings should be used-contact Roy Roub to buy the fittings and couplings.

Figure3: (a) In order to pull the cold head unit out of the magnet, 4 hex screws (OUTER ONES)
should be removed as shown in the cartoon. The cold-head should be taken out very slowly (b). Before
disassembling the cold-head, the He-flux lines should be disconnected, and the excess gas should be vent using
appropriate couplings, one by one, first for the supply line and then the return line.
Once the cold-head is carefully removed from the magnet, it has to be kept in a holder/shield provided
by the Sumitomo and keep it safely. The old cold head should be sending back to Sumitomo.
Figure 4: (a) A top view of magnet (helium chamber) after removing the cold head (c) New replacement coldhead,
already cleaned by the Sumitomo. The coldhead can be taken out from the casing by unscrewing the 4 large hex-
screws (same screws are being used to attach to the magnet). When we request exchange of cold head in the
future, we will receive the same fully tested coldhead with attachments from Sumitomo. When it is taken out we
need to purge it with He-gas. Also the inner portion (a) of the magnet also should be purged for some time with
low pressure He-gas before assembling the cold-head to the magnet. (c) The refurbished cold-head sent by
Sumitomo will be filled with He-gas, therefore it has to be vent before start connecting to the magnet (Youngwoo
please confirm this step-I am confused why it was not directly connected, then we did not need to re-purge the gas
again? Confirm it with Roy, may be?).

Figure 5: (a) The magnet chamber was cleaned with Kim wipe (ethanol) and then subsequently purging with He-gas
prior to attaching the cold-head. (b) Disassembling the refurbished cold-head from the casing by unscrewing the 4
hex screws.
After connecting cold-head to the magnet, it has to be purged with He-gas prior to re-connecting the flux lines-
otherwise the flux lines and the He-compressor will be contaminated.
Figure 6: (a) The He-compressor is powered off. (b) The main power is turned back on. For purging the cold head
without connecting the flux-lines, the cold-head drive should be turned on (c): however in the image it is off). Cold-
head drive switch should be turned off after reconnecting the flux lines and the He-compressor in the normal
operational mode.

Figure 7: (a) For purging the cold-head, the gas inlet from helium gas cylinder (not from helium compressor) should
be connected to supply inlet of the cold-head using appropriate fittings (gas connector). Outlet was kept opened
using gas connector. The fuse and the main power switch to the He-compressor should be kept in the ON position
(b).
Figure 8: (a) After making all connections from the He-tank to the supply line and keeping the return open, and
keeping the pressure around 10 Psi (for few min) and then to about 100 Psi as shown in (b), the cold-head has to be

purged. Before starting the automatic purging using the He-compressor, the compressor main power switch and
the drive switch should be kept ON.
After purging the cold-head from the He-cylinder using He-compressor settings for about 20min, the return valve
can be closed. Close the He-tank, and the supply inlet. Now the Cold-head is ready to be connected to the He-flux
lines. First, connect the flux lines to the He-compressor and then to the cold-head. Make sure that the main power
switch and the front panel switch of the compressor are turned off prior to re-connecting the flux lines. Then turn
off the cold-head drive switch. Now the He-compressor is ready to operate. Switch on the front panel power
switch, then the compressor will start operating. Initially the pressure reading will be around 2.6 MPa, but it will
reduce slowly to 2.2 MPa over about 24h of operation.
SERVICE DETAILS OF THE COLD-HEAD AND THE HE-COMPRESSOR
Serial #
Contact details of the IL, Sumitomo Inc. (SHI Cryogenics):
He-compressor service:
● Sumitomo (SHI) Cryogenics of America, Inc. ●1500-C Higgins Road, ●Elk Grove Village, ● IL 60007
PH # 847-290-5801 / Fax# [phone]
Personal Contact: "Skica, Aya" <[email protected]>
The weight of the He-compressor is about 100 pounds and the wooden crate has about 250 Pounds. Therefore we need
to contact Fed Ex-freight service for shipping.
Cold-head service:
● Sumitomo Cryogenics of America Inc. ●1833 Vultee Street ● Allentown, PA 18103
● Tel: [phone] ● Fax: [phone] ● www.shicryogenics.com
Personal Contact: "Raub, Roy" <[email protected]>
He-CSW-71 compressor service: ("Skica, Aya" <[email protected]om>): Tasks and prices
1. Preventative maintenance: $2,000 (includes oil change, replacement of minor electrical
components, and sheet metal, if required.)
2. Absorber replacement: costs additional $1,500. (The absorber needs a replacement:
Sumitomo advices to do it since compressor is already been passed 40,000h. (max. usage of
absorber is 30,000h), otherwise the oil will be contaminated soon, cause motor to
malfunction..
3. If the motor capsule, heat exchanger, oil separator, or control board require replacement
there is additional cost.
He-compressor Model# CSW-71C, S/N: 47C07087D
Cold head: Model# RDK-408D2, S/N: AJD 07016

4. Gasline service: $300 each. Includes gas cleanup, leak check, and replace Aeroquip
fittings.
5. Wooden crates: $300
6. Shipping invoice (empty wooden crates to us and the shipping the instruments back to us)
will be send to us separately. We will use our credit card to pay for the shipping from here
to their Chicago facility.
The compressor performance will be fully tested prior to sending us.
Cold head service: ("Raub, Roy" <[e-mail]>): Tasks and Prices
1. Basic Fee for quantity 1 coldhead (RDK-408/415) $8,700.00
2. Labor (1 day per engineer) Included
3. Travel & Living Expenses: Billed at actual
Tasks:
1. Removal of the expired/worn parts of the coldhead.
a. The warm housing and parts contained within which includes valves disc, valve stem, scotch
yoke, guide bushings, all orings.
b. The 1st and 2nd stage displacer assembly.
2. Solvent clean and inspect the cylinder assembly.
3. Install a new oring on warm flange.
4. Install a completely reconditioned and qualified warm end/displacer assembly consisting of
the parts listed in 1a. & b. above.
5. Reassemble the coldhead.
6. Perform a gas cleanup on the coldhead.
7. Reconnect gaslines.
8. Leak check all disturbed joints and final testing of the He-compressor
UHP 300 Grade 5 helium gas cylinder (purity 99.999%) from Airgas should be provided for the
service.

Gas Lines
Technical Manual
Sumitomo (SHI) Cryogenics of America, Inc.
1833 Vultee Street
Allentown, PA 18103-4783
U.S.A.
Revision G: December 2011 261320A

TABLE OF CONTENTS
i
Page
DESCRIPTION .......................................................................................................................1
SPECIFICATIONS..................................................................................................................3
Minimum Bend Radius ......................................................................................................3
Pressure and Temperature Ratings...................................................................................3
Identification Labels...........................................................................................................3
Installation Tools ...............................................................................................................4
MAINTENANCE .....................................................................................................................5
Disconnect Gas Lines .......................................................................................................5
From the Compressor ..................................................................................................5
From the Cold Head .....................................................................................................6
Leak Check .......................................................................................................................6
Gas Line Repair ................................................................................................................7
Venting..............................................................................................................................7
Repair Self-Sealing Couplings...........................................................................................8
Replace the Gasket Seal..............................................................................................8
Repair or Replace a Coupling.......................................................................................9
Charge Pressure Verification........................................................................................... 10
Gas Cleanup and Recharging ......................................................................................... 11
PARTS ................................................................................................................................. 13
Ordering.......................................................................................................................... 13
Parts Identification and Numbers..................................................................................... 13
ILLUSTRATIONS
Figure 1 Typical Helically Corrugated Gas Line Construction .........................................1
Figure 2 Break Gas Line Connection from Compressor..................................................6
Figure 3 Disconnect Gas Line from Compressor ............................................................6
Figure 4 Break Gas Line Connection from Cold Head ....................................................6
Figure 5 Disconnect Gas Line from Cold Head...............................................................6
Figure 6 Aeroquip Male Coupling Parts ..........................................................................8
Figure 7 Remove Coupling from Gas Line......................................................................9
Figure 8 Aeroquip Female Coupling Parts ......................................................................9
Figure 9 Parts Identification .......................................................................................... 13
SJM P/N261320A

ii
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DESCRIPTION
1
Gas lines are needed to connect compressors to cold heads (expanders) to complete the
system. Gas lines are constructed from helically corrugated stainless steel tubing covered with
metal braid or from soft copper tubing. All gas lines are equipped with Aeroquip self-sealing
couplings and are furnished cleaned, charged with helium gas and leak checked.
Each cryogenic system includes interconnecting gas lines to carry helium gas refrigerant to and
from the components. A gas line carries high-pressure gas from the compressor to the cold
head and another gas line returns lower pressure gas to the compressor.
Flexible gas lines simplify installation. The self-sealing couplings maintain the gas charge and
purity by minimizing gas loss when connections are being made or broken and by preventing
the entrance of contaminants. Dust plugs protect the coupling threads from damage and also
help to maintain cleanliness.
Figure 1 Typical Helically Corrugated Gas Line Construction

2
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SPECIFICATIONS
3
Minimum Bend Radius
Gas Line Type Diameter
mm (inches)
Minimum bend radius
mm (inches)
Helically corrugated
stainless steel
19 (3/4) I.D. 230 (9)
Helically corrugated
stainless steel
13 (1/2) I.D. 180 (7)
Copper tubing using a tube
bender
17 (5/8) O.D. 57 (2 ¼)
Copper tubing without
using a tube bender
17 (5/8) O.D. 460 (18)
Pressure and Temperature Ratings
Pressure and Temperature
Ratings
Stainless Steel and Copper
Design pressure, max. 2760 kPa (400 psig)
Operating pressure, max. 2410 kPa (350 psig)
Charge pressure, max. 1860 kPa (270 psig)
Operating temperature, max. 49º C (120º F)
Operating temperature, min. 4º C (40º F)
Identification Labels
Labels on the gas lines identify their function in the system as follows:
SUPPLY (color coded red) Helium gas supply to the cold head from the
compressor.
RETURN (color coded green) Helium gas return from the cold head to the
compressor.
Separate labels are furnished by SCAI with standard gas lines for the customer to attach to the
gas lines. See the Installation section in the System manual.

Specifications
4
Installation Tools
Properly sized open-end wrenches are needed to install and remove gas lines. SCAI can
furnish (optional) one each:
Wrench, 1" open end x 3/4" open end
Wrench, 1 1/8" open end x 5/8" open end
Wrench, 1 3/16" open end x 1 3/16" ratchet
P/N SK30017C3
P/N SK30017C2
P/N SK30017C1
For MRI systems with an RF shield, gas feedthroughs may be furnished for gas line installation through
the shield. Special wrenches may be required to fit the feedthroughs.

MAINTENANCE
5
Disconnect Gas Lines
AVOID INJURY. Extreme cold can cause frostbite. When handling system
components, be careful not to touch any frosted parts.
AVOID INJURY. Disconnect gas lines only when the compressor is stopped.
Disconnecting the cold head while it is cold can create excessively high internal
pressure as the gas warms. Material failure and uncontrolled pressure release
can cause injury.
AVOID INJURY. Use two wrenches when disconnecting a gas line coupling to
avoid loosening the compressor’s or cold head’s coupling. Gas pressure can
project the coupling with enough force to cause injury.
AVOID GAS LEAKS. Keep the gas line couplings aligned when making or
breaking a coupling connection. Leaks can occur due to the weight of the gas
line or due to a sharp bend near the connection. Crimping from repeated
bending and repositioning can cause damage to gas lines.
PREVENT EQUIPMENT DAMAGE. Do not use a clamp over hose section of
flex gas line.
Disconnect from the Compressor
Tools required: Open-end wrenches
1. Always use two wrenches. Use one wrench to hold the compressor coupling. Use the
second wrench on the gas line coupling nut to break the connection. See Figure 2.
2. After breaking the connection, hold the coupling adapter with one wrench. Remove the gas
line coupling from the compressor coupling with the second wrench. See Figure 3.
3. Screw a dust cap finger tight on to the compressor coupling.

Maintenance
6
Figure 2 Break Gas Line Connection Figure 3 Disconnect Gas Line
from Compressor from Compressor
Disconnect from the Cold Head
Tools required: Open-end wrenches
1. Always use two wrenches. Use one wrench to hold the cold head coupling. Use the second
wrench on the gas line coupling nut to break the connection. See Figure 4.
2. After breaking the connection, hold the coupling adapter with one wrench. Remove the gas
line coupling from the cold head coupling with the second wrench. See Figure 5.
3. Screw a dust cap finger tight on to the cold head coupling.
Figure 4 Break Gas Line Figure 5 Disconnect Gas Line
Connection from Cold Head from Cold Head
Leak Check
Leakage of helium gas is the only likely problem to originate on a gas line. Use of a helium
mass spectrometer leak detector is recommended. If no mass spectrometer is available, a
liquid leak detector solution may be used on the coupling joints.
With the gas lines connected to the compressor and to the cold head, leak check the connected
coupling joints.

Maintenance
7
The flat gasket in the face of the male coupling seals the joint. A leak at this gasket seal can be
detected only when a gas line is connected. A leak here can be caused by:
•the coupling not fully tightened
•a worn, damaged or missing gasket seal
•dirt on or under the gasket seal
•dirt on the female coupling’s mating surface
•damaged parts on either coupling which prevent proper mating or sealing
Gas Line Repair
Leaks in the helically corrugated metal tubing cannot be repaired. Discard the damaged gas
line and install a new one.
Leaks at welded joints require special skills to repair. Consult an SCAI Service Center.
Leaks at the self-sealing couplings can be repaired by replacing worn or damaged parts.
Vent the gas line before beginning to disassemble it except when replacing a gasket seal.
When couplings are frequently disconnected and reconnected, it is important to wipe the
mating parts (threads and faces) with a clean, lint-free tissue or cloth.
Venting
Tools required: Adapter fitting with valve, 8M Aeroquip, P/N SK8217A2.
Open-end wrenches
NOTE
Adapter fittings are available as optional accessories from SCAI.
1. Disconnect the gas line from the system. Install a dust cap on each of the male couplings of
the compressor and cold head, or on the RF feedthroughs, if used in the system.
2. Be sure the valve on adapter fitting SK8217A2 is closed. If only one coupling on the gas
line is to be repaired, install the adapter fitting on the good coupling. Use two wrenches.
3. Slowly open the valve on the adapter fitting to vent the entire charge of helium gas.
4. Close the adapter fitting’s valve. Do not remove the adapter fitting. It will be used for gas
cleanup and recharging.
NOTE
Gas cleanup and recharging of the gas line are always required if a coupling
has been repaired. Instead of venting the gas line to atmospheric pressure,
some operators prefer to connect an adapter fitting and a charge line to the
coupling not being repaired, to purge the gas line with helium during repair. Set
the helium gas regulator at 35 kPa (5 psig) or less to prevent air from entering
the gas line and contaminating it.

Maintenance
8
Repair Self-sealing Couplings
AVOID INJURY. Always vent a gas charged component before beginning to
disassemble its couplings. Gas pressure can launch a loose coupling with
enough force to cause personal injury.
PRESERVE YOUR WARRANTY. Modification to equipment without the consent
of the manufacturer will void the warranty.
Damaged threads, leaking seals or a leaking valve assembly may require replacement of
coupling parts or replacement of the complete coupling half.
Replace the Gasket Seal
Tool required: Needle or a narrow, flat blade screwdriver
Cotton swabs
Isopropyl alcohol
From repeated connecting and disconnecting the coupling, the gasket face seal just inside the
face of a male coupling may begin to leak and require replacement. The gasket seal is replaced
while the gas line is disconnected.
1. Carefully pierce or pry the old gasket face seal and pull it from its recessed ring in the body
of the coupling. Discard the face seal. See Figure 6.
2. Using isopropyl alcohol on a clean, cotton swab, carefully remove any remaining adhesive
from the coupling’s recess. Avoid getting alcohol on the face of the poppet.
3. Dry the recessed surface with a clean, lint free cloth.
4. Do not apply any adhesive. Press a new gasket seal into the recessed ring.
Figure 6 Aeroquip Male Coupling Parts

Maintenance
9
Repair or Replace a Coupling
Tools required: Open-end wrenches
This procedure applies to both male and female couplings on gas lines, compressor and cold
head.
1. Vent the charged component using the venting procedure in this manual or in the
Maintenance section of the appropriate manual.
2. If the coupling to be repaired has the venting adapter fitting attached, remove the adapter
fitting. Use two wrenches.
3. Use two wrenches to disconnect the coupling body from the adapter. Hold the adapter with
one wrench. Remove the coupling body with the other wrench. See Figure 7.
4. Push the valve assembly from the coupling body. It is not fastened. Examine all parts and
replace any that are damaged or replace the entire coupling half. See Figures 6 or 8.
Figure 7 Remove Coupling from Gas Line
Figure 8 Aeroquip Female Coupling Parts
5. Remove the O-ring from the gas line adapter.
6. Wipe the O-ring groove to be sure it is clean. Lightly coat a new O-ring with vacuum grease.
Install the O-ring in the gas line adapter.
7. Wipe the valve assembly with a clean, lint-free cloth. Insert the valve assembly into the
coupling body from the rear.