PREFACE
SAFETY
The same applies when there is a suspicion that the integrity or function of the container is not working normally. Good safety practices dictate that the contents of a damaged or suspicious container should be carefully emptied as soon as possible. Additionally, a damaged or suspect container should not be refilled unless the unit has been repaired and recertified.
As a rule of thumb, when a container is suspected of abnormal operation or has sustained actual damage, good safety practices must be followed. In the event of known or suspected canister vacuum problems (even if an extraordinary circumstance such as those mentioned above has not occurred), do not continue to use the unit. Both the worker and the "buddy" should be equipped with self-contained breathing apparatus.
Carbon dioxide is a compound formed by the combination of carbon and oxygen atoms in a 1:2 ratio expressed by the chemical symbol CO2. Depending on the temperature and pressure to which it is subjected, carbon dioxide can exist in the form of a solid, a liquid or a gas.
INTRODUCTION
Transport and placement of the tank must be carried out in accordance with the rope instructions provided in the table. All operations are performed entirely by control valves located on the underside of the tank. For this reason, the tank must be thoroughly purged with the appropriate gas before filling.
Pressure building systems remove liquid from the bottom of the tank and vaporize it into a gas by adding heat. The heated gas then returns to the top of the vessel, where it raises the pressure in the tank. The pressurization system will increase the pressure in the tank to maintain the correct operating conditions for the tank.
In a direct gas application where the tank pressure is reduced by withdrawing gas from the top of the tank. An optional cooling coil can be built into the vessel, which recondenses the gas at the top of the tank and reduces the pressure, when used with a mechanical cooling system.
INSTALLATION
Connect to the lifting eye on the top of the tank and on the leg as shown in the rigging illustration. Disconnect any chains, straps or shipping supports that may have been used to hold the tank to the bed of the truck. Raise the tank only a few inches and check that there are no additional connections between the tank and the trailer.
Remove the tank from the trailer and place it on the pad or designated holding area while the pad is being built. With the storage raised just a few inches from the floor of the cargo container, slide the tank horizontally off the bottom of the cargo container. Lift the tank and place it on the pad or designated holding area while the pad is being built.
The receiving inspection is one of the most important procedures in the life of the tank and must be carried out thoroughly and conscientiously. Examine the 5g impactograph located on the inside of the tank legs attached to the tank head. If the carbon dioxide storage tank is to be installed at the user site, the following should be considered prior to installation.
The most important considerations when choosing a location for the VS-CO2 are the soil stability of the location, accessibility for maintenance and proximity to the liquid delivery point. Because many fluid supply hoses are at least 15 feet long, the container should be no more than 10 feet from the possible access point to the cabinet. If the tank is to be located outdoors, the location selected shall be such that the container and associated equipment (if any) will not be beneath or exposed by the failure of electrical lines, flammable or combustible liquid lines, or combustible gas lines.
If the tank is located indoors, the building must be non-combustible, adequately ventilated and used exclusively for gas storage. Installation of a carbon dioxide storage tank should be supervised by personnel familiar with the tank's construction and intended use. After installation, all field-raised piping and tank connection points should be tested at maximum operating pressure to check for leaks.
OPERATIONS
Close all valves except the pressure builder inlet and outlet valves (HCV-3 and HCV-11), if pressure builder is installed, and liquid phase (high) and gas phase (low) valves (HCV-10 and HCV-8). NOTE: When a solenoid valve is used to control the pressure building circuit, it must be energized. Open the leveling valve (HCV-9) to prevent damage to the meter before closing valves (HCV-8 and HCV-10).
NOTE: Careful checking for moisture in the phase lines will ensure smooth operation of the liquid level gauge. Reconnect the liquid level gauge (LI-1) and open the liquid level control valves (HCV-8 and HCV-10), then close the balancing valve (HCV-9). After cleaning the tank, but before filling, check that the following valves are open or closed as shown.
Pressure Building Inlet Valve (HCV-3) Pressure Building Outlet Valve Closed (HCV-11) Liquid Phase (High) Shutoff Valve (HCV-10) Open. Verify that the supply unit contains the correct product to be transferred and that the supply unit and tank fill assembly are for CO2 service. Verify that all valves except the high liquid phase (HCV-10) and the low gas phase (HCV-8) are closed.
Pressure building inlet valve (HCV-3) Pressure building outlet valve open (HCV-11) Liquid phase (high) valve open (HCV-10) open. The tank operating pressure should never be vented below 165 psig (11.6 Kg/cm2) while the liquid is in the vessel to prevent the liquid CO2 temperature from falling below the vessel's minimum design temperature. A vessel that is in service must be refilled using the bottom fill and vapor return valves (HCV-1 and HCV-4).
Verify that the contents of the feed unit are the correct product to be transferred. Verify that all valves except liquid phase (high) (HCV-10) and gas phase (low) (HCV-8) are closed. Verify that all valves except liquid phase high valve (HCV-10), gas phase low valve (HCV-8) are closed.
MAINTENANCE
By emptying all or most of the liquid from the tank, as any product left in the tank is lost during the cleaning procedure. Bulk CO2 tank contents should be reduced to approximately 500 pounds or less as any remaining product is discharged or lost during the cleaning and flushing procedure. Reduce bulk CO2 tank pressure to about 150 PSI below the transport pump capacity to ensure powerful flow into the tank.
Do not depressurize the bulk CO2 tank below 165 PSI to maintain the tank temperature above –30 degrees F. Continue to monitor the tank pressure and if the pressure drops below 165 PSI close the bottom fill valve (HCV-1) and allow the pressure to build to an acceptable level before proceeding. Discharging liquid CO2 into the atmosphere can produce high-velocity dry ice particles that must be directed away from people or anything else that could be harmed in the process.
If the tank is used in areas with extremely hot or cold climates, inspection intervals should be shortened. If any of the above conditions occur, remove the unit from service as soon as possible and contact the factory for advice on drum vacuum testing. CAUTION: Before removing or adjusting the tank pressure gauge or liquid level gauge, ensure that the liquid phase meter valve (HCV-10) and the gas phase meter valve (HCV-8) are closed.
The required repair procedures, as listed in the Troubleshooting column, can be found in the Repairs section of this section. Remove all liquid and depressurize the container if necessary before replacing any component(s) exposed to pressure or liquid CO2. Always reassemble parts in the reverse order of disassembly.
Release the pressure in the tank by slowly opening the vapor recovery valve (HCV-4) until the venting stops and the gauge (PI-1) reads 0 psig. The safety valve opens and releases gas to protect the tank from overpressure. Do not use the VS-C02 again until all leaks have been repaired and the tank has been retested.
SPARE PARTS LISTS
ILLUSTRATIONS
