Proper Sizing of a Micro-Bulk Vessel.

For the benefit of space, I’m going to keep this simple. A good “rule of thumb” for Distributors to follow in sizing a vessel, is that a vessel should be sized so it is filled every three-four weeks. A careful review of your Customer’s consumption requirements (current and future), site considerations, and product availability will be essential information. Selecting the optimum size cryogenic storage vessel for your application need not be a difficult task.

First of all, what are the consumption requirements? Most importantly, what are the monthly usage requirements in cubic feet? If the customer is upgrading their current storage supply, they can simply review their current monthly consumption reports. This will tell their usage on a monthly basis. A review of future growth opportunities, as well as seasonal changes should also be included in your calculations. If the anticipated demand is projected to increase or change, you can adjust the storage capacity to better suit those requirements.

Today, there are many choices. You can find a cryogenic storage vessel that will allow you to maximize your operation. Once you have determined your customer’s monthly usage, look at the capacity of each vessel below and select the vessel that best covers your needs for a 3-4 week period.

Micro Bulk Capacity in Cu. Ft.

For example, if my customer is using a laser system and they consume 40,000 cu. Ft. of nitrogen a month, I would install a 3000-liter vessel. This will provide product at the recommended pressure and flow rate, plus give them plenty of cushion in case they need to run the Laser more than normal. However, if their usage is above 90,000 cu., a 3000-liter vessel would be too small requiring a fill at least twice a month. If this is the case. the correct vessel choice would be a 6000 liter. Roughly ¾ of the vessel's capacity. A size 2000 liter would also work, but would also be too small and not provide any cushion if product supply were to be interrupted or demand ramps up.  

What pressure, flow rate, and purity will you require? This information will be critical in designing the vaporization (flow rate), regulation (pressure), and filtration (purity) for the system.

Site Survey – Selecting the optimum location to install the vessel is the key to success. Typically, a site survey should be conducted to determine the acceptability of each potential install site. We recommend working with your product supplier on the evaluation.  Pay close attention to utilities: avoid overhead wires, piping, flammable storage, chemical/corrosives outdoor vents, doorways, and other points of access.   For best results, the micro bulk vessel should be installed in a secure area as close as possible to the tool. We recommend a fenced area with room for an external vaporizer and regulation. The Fill point/connectors should be located in an easily accessible area. Keep in mind, you will need to provide access for large trucks to enter and depart easily at any time of the day.

Product availability – When initially setting up the system, you will want to coordinate with your product supplier on topics such as Delivery information, monthly Use, bulk connections, site access instruction, and equipment compatibility. You want to ensure that your product supplier can fill your micro bulk without any issues.

Depending on your location, product supply, and delivery could be affected by several other factors: Weather, traffic, road conditions, product shortages, and equipment problems to name a few. During the middle of winter, it is much more difficult to coordinate all of these variables. If you are in a remote location, you might want to consider having a backup source of supply.

Vaporization –

The Arctic Fox 6000L micro bulk has an “on-board” vaporizer that will deliver up to 3550 SCFH of Nitrogen at 500 PSI. This is typically adequate for most Lasers, however, newer lasers are requiring higher flow rates (5500+ SCFH). This typically requires a standalone vaporizer, so allow extra space for the upgrade in the future.

As you can see there are many variables to consider when selecting a micro-bulk. However, with accurate consumption information, proper site preparation, and co-ordination with your Cryogenic Supplier you will be able to install the optimum vessel for your Customer’s requirements