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Introduction
This guide is intended as an overview of the operation of the SRM compressor and includes instructions for use of the main and backup Haskris Chill Water system. For in depth operational instructions, see the Cryomech Compressor vendor manual and the Haskris Water Chiller vendor manuals.
The Superconducting Rock Magnetometer (SRM) uses a cyro-compressor to keep a small amount of Helium compressed in order to reach superconducting temperatures. The compressor is water cooled.
The complete Cryomech 2800 He compressor manual can be found here >>> PT405-RM CP2850 Installation_ Operation_ and Maintenance Manual.pdf
Chill Water Sources
The SRM Cryomech 2800 (Figure 1a) chilled input line and warm water return line are directly plumbed the water cooled Haskris (Figure 1b- the white unit at the forward end of the paleomagnetics lab) through a set of three way valves. This unit is in turn cooled by the ship's chill-water. In the event that the ship’s chill water fails or is shut down for maintenance or for repair, a backup water cooling system is in place. The backup system is a Haskris Air Cooled Water Chiller system (Figure 1c). The Haskris is also plumbed to the compressor via the set of three way valves. Switching between these systems requires that the user turn the three way valves (explained below in detail).
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| Figure 1a: Cryomech 2800 Series Compressor for SRM. The compressor is located at the aft end of the paleomagnetics lab just behind the load end of the SRM track. | Figure 1b: Main Haskris Water Chiller (water cooled). This unit is located at the forward end of the paleomagnetics lab and requires ship chill-water. | Figure 1c: Backup Haskris Water Chiller (air cooled). This unit is located at the forward end of the Core lab under the Forward Description Table. Since the unit is air cooled, it will generate heat in the lab space. |
Monitoring the System
To monitor the status of the compressor, use the CryoWATCH program (Figure 2a) which is available on the SRM computer. The compressor is connected to the SRM PC via an RS232 cable. The application displays the status of the compressor and logs these values to a text file (Figure 2b). The communications setup should be the default baud rate of 115200 and a slave address of 16, and the com port may need to be adjusted. When first logging in or restarting the computer, open IMS before opening Cryowatch, otherwise IMS will have trouble with some of its COMs (this problem can be fixed by updating the "CRYOMECH" VISA-Alias in the Cryowatch program).
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| Figure 2a: CryoWATCH Panel Desktop Icon | Figure 2b: CryoWATCH window. User may monitor water temperatures and oil temperatures after changing the chill water supply. |
The user may set the Logging File Path and the log period (in seconds) as they see fit. The right hand side of the virtual panel with logging displays the temperatures for the water in, water out, Helium gas, and the oil temperature. The arrow at the boundary between the red and blue bars indicates the current temperature. The upper-most black bar indicates the maximum temperature seen and the lower-most black blue bar marks the minimum temperature seen. This panel also displays the amps that the motor is using and the current high and low pressure of the helium lines. Acceptable temperature and pressure ranges are given in Table 1. The additional tabs available allow the user to view graphs of the temperatures, pressures, and other parameters over time. This is useful when adjusting the water flow rate. Caution: The Panel tab will allow the user to turn the compressor on and off.
| Table 1: Acceptable temperature and pressure ranges for Cryomech 2800 Series Compressor | |||||||||||||||
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| *Since the Cryomech water temperature is now set by Haskris units for both the main and backup system, these temperature windows are much tighter and the new limits need to be determined and set in the Cryowatch program. |
Alternatively: If CryoWATCH is unavailable, the Cryomech Virtual Panel with Logging panel is available. This can be found on the SRM desktop at C:\Users\daq\Desktop\cryomech\Cryomech\virt_panel. Set the com port number correctly, designate a file path, and the compressor data will be logged.
Trouble Shooting
If you notice the SRM area is unusually quiet and/or an audible beep is coming from the compressor, check the front panel of the compressor (Figure 3). It will display the fault that has caused the compressor to shut down. Check the Cryomech Compressor user guide for error messages and how to handle each.
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| Figure 3: SRM Cryomech Compressor. The red box indicates the display which shows the error messages. |
Switching Chill Water Systems
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Figure 4a: Diagram of the main Haskris and plumbing with its valves set correctly. | Figure 4b: Diagram of the backup Haskris and plumbing with its valves set correctly. |
The ship’s chill water may be shut down for routine maintenance or repair. In this situation, the crew should notify the technical staff prior to the shutdown. This will allow a technician to switch to the backup Haskris system before the chill water is shut down, preventing the compressor from shutting down and allowing the SRM system to continue working uninterrupted.
The backup system should be ready to put in to service at anytime. In order to ensure this, both systems should be cleaned and purged at the end of every exepdition as described below.
If the ship’s chill water system shuts down unexpectedly, the main Haskris will no longer be able cooled, and the cooling water delivered to the Haskris will begin to warm up. Cryowatch's alarms trigger when this water in (to the Cryomech) exceeds 70°F, though no audible warning is set up. (Since main and backup systems deliver nearly constant water temperature, can we set up and audible alarm? Either on the computer? Or the an oil temperature alert on the Cryomech and not just the shut down alert at 120°F.) kdjafkldsjfl;kasjdflfadf
the compressor will shut off, beep audibly, and signal a “low flow” error on the front console of the compressor. You have approximately 10 minutes from the time the compressor shuts off to the time when the SRM warms above 7 K and loses the trapped field.
From ship’s chill water to Haskris water chiller supply:
1) Open the Haskris water tank cover to monitor the water level. (Figure A8).
The Haskris is filled with tap water or ship’s chill water. If you open the tank and the surface of the water is growing biologic experiments, it is best to empty the tank with a wet vacuum and refill the Haskris water tank before starting the system. If the ship’s chill water is still on, the tank can be filled by opening the outlet 3 way valve and allowing the water returning from the compressor to flow into the Haskris for a short period of time. If the ship’s chill water is off, fill the Haskris tank with clean, drinkable water (Not Deionized water!) via a bucket. ROUTINE MAINTENANCE -> At the end of every expedition, remove the water, clean and replace with drinkable water.
Figure 8: Haskris Water Chiller with water tank open. Water surface should be clean. Do not pump dirty water through the Haskris.
The blue box indicates the power switch for the Haskris. The orange box indicates the water temperature set temperature and actual temperature as well as the Haskris controls.
2) Turn on the Haskris power using the switch on the front of the Haskris (Figure 8). Wait 10 seconds. The Haskris is a closed loop system and can be started before the water supply is diverted as long as there is water in the Haskris tank. If the water level drops significantly, add more water to the tank before opening the valves.
3) Use the up and down arrows to set the desired water temperature for the water leaving the Haskris (Figure 8). The water temperature should be set at 65 degrees F or above. Remember, the goal is to keep the compressor oil temperature as close to 90 degrees F as possible.
4) Locate the black 3 way valves at the forward end of the paleomagnetics lab (Figure 9). When the ship’s chill water is used to supply cold water to the SRM compressor, the valves should point toward the chill water lines (white arrows pointed toward the right when facing aft) (Figure 10).
Figure 9: Three Way Valve controls for the compressor cooling water. By rotating these valves the user may switch
from ship's chill water to the Haskris Water Chiller or vice versa. Arrows on hoses indicate direction of water flow.
Figure 10: Valve positions when using ship’s chill water for cooling the SRM compressor.
5) Turn both valves 180 degrees. This can be done simultaneously or one at a time. This step should be done quickly to avoid completely draining the Haskris water tank or overfilling the tank. Make sure the valves are turned the full 180 degrees.
When the Haskris water chiller is used to supply cold water to the SRM compressor, the valves should point toward the Haskris water lines (to the left when looking aft) (Figure 11).
Figure 11: Valve handles after being turned to Haskris mode. Note that the white arrows point toward the Haskris Water Chiller hoses.
6) Once the valves are turned, monitor the compressor vitals using the CryoWATCH software on the SRM computer. Monitor the water temperatures and oil temperatures on the right hand side of the screen.
To switch back to ship’s chill water from the Haskris, turn the valves back to the original position (Figure 10). Turn off the Haskris and monitor the oil temperature in the CryoWATCH software.
Archive Versions:
- CryomechCompressorandHaskrisWaterChiller_exp378.pdf: PDF version of this wiki page as of 2020-02-24