With Cryomed cryosaunas, you have two options for liquid nitrogen storage and feed – non-pressurized Dewar containers or larger pressurized cryogenic tanks. In most cases, they are not interchangeable. Therefore, before buying a cryosauna, it is crucial to choose the type most suitable for your needs.
What is a Dewar?
A cryo Dewar is a two-walled vacuum flask capable of keeping a relatively constant temperature of a cryogenic liquid over a long period. Design-wise, Dewars are big thermos bottles with loose-fitting caps.
Cryogenic Dewars are a good fit for cryotherapy centers with low to moderate customer flow. As a rule, Cryomed’s open-top cryosaunas come with two 35-liter non-pressurized tanks or, optionally, with two 50-liter tanks. If you expect more than ten cryo-goers daily, you might want to opt for pressurized cryogenic liquid cylinders.
What is a cryogenic storage cylinder?
A liquid nitrogen cylinder is a pressurized vacuum-jacketed tank. It features valves for refilling and withdrawing liquid nitrogen, a pressure release valve and a pressure indicator for safety. In addition, a cylinder is fitted with a float level gauge to control the liquid nitrogen consumption.
Cryogenic Dewars vs. pressurized cryogenic storage tanks
Though both tanks serve the same purpose, non-pressurized Dewars and pressurized liquid nitrogen cylinders differ from each other in:
Non-pressurized Dewar tanks are smaller and easier to handle. In Cryomed Pro or Cryomed Basic, a cryo Dewar is rolled into the cryosauna. In smaller models, like Cryomed One or Cryomed Mini, a Dewar sits next to the device. When not in use, Dewars can be stored in a utility room.
A pressurized cryo cylinder always stays outside a cryosauna. In smaller premises, a tank can sit in another room or even outside the building. The cryotherapy machine and the tank are linked by a standard two-meter cryogenic hose. However, Cryomed’s team can always find a suitable solution for your location, so feel free to reach out.
A 35-liter Dewar container weighs 17 kg when empty and comes with a wheeled platform, making it easy to move. In some countries, you can put it in your car and get it refilled at your supplier’s. However, in the majority of cases, such tanks get refilled at your place from a specialized truck.
Pressurized tanks are heavier and more large-sized. They are always refilled or replaced with a full tank at your place. Make sure to consult your supplier about any restrictions linked to your location in advance. If your business is on the 3rd floor in an old high-rise building without a heavy-duty elevator, Dewars may be a safer bet.
Pressurized tanks have a higher evaporation rate than non-pressurized cryo Dewars. In addition, nitrogen gets lost along the hose and on the junctions between the valve and the hose and between the tank and the hose. However, with a high customer flow, this loss is negligible.
For reference, pressurized tanks evaporate 2 to 5% of their capacity, depending on the manufacturer. Non-pressurized Dewars used by Cryomed evaporate 0.5% of their capacity.
Liquid nitrogen cylinders are expensive. Their price tag can easily reach up to several thousand euros, depending on their capacity and manufacturer. That’s why many cryopreneurs prefer renting cryo cylinders from local nitrogen suppliers.
A Dewar costs between 1,000 EUR and 1,500 EUR. Depending on your customer flow and nitrogen supply terms, you might need to buy more Dewars in addition to the two tanks you get together with a cryosauna.
Number of sessions
As nitrogen consumption affects the number of sessions you can get out of your cryogenic container and, eventually, the session cost, there are a couple of things to bear in mind.
Consumption of liquid nitrogen in cryogenic tanks depends on:
- The session time (1.5 to 3 minutes).
- The session temperature (for a first-timer, the operator can choose -110℃; for a veteran user, -150℃).
- The evaporation rate from liquid nitrogen tanks. The higher the room temperature, the more nitrogen you lose daily.
That is why the number of sessions you can get from one cryogenic container is tentative.
Standard non-pressurized Dewar tanks have a 35-liter capacity, sufficient for one cooling and up to 8 treatment sessions. It is a good choice if you expect up to ten customers per day or buy a cryosauna for home use.
Pressurized tanks vary in capacity from 100 to 5,000 liters, but the most usual option is 240 liters. Out of a 240-liter tank, you can have some 60 sessions.
A cryogenic liquid cylinder is a convenient and cost-effective option that does not require frequent refills. It is most suitable for businesses with high customer flow, like a gym, a spa, or a clinic.
How to choose between a Dewar and a nitrogen tank?
Now that you are clued in on the two types of cryogenic vessels, let’s see how to make the best choice.
- The expected number of daily sessions is decisive. The higher the customer flow, the more nitrogen you need. In this case, pressurized nitrogen tanks are a more convenient option. Cryogenic Dewars are suitable for cryopreneurs with up to 10 customers a day.
- Access to your cryotherapy treatment room is the second most important factor. With stairs or high floors with no elevator Dewars are a more viable solution. A flight of two or three stairs can be covered with a board you can roll the tank over, but anything higher makes the delivery of a pressurized tank impossible.
- Another factor to consider is the rental and delivery fee for cryogenic liquid cylinders in your area. Situations may be different.
- A supplier may refuse to sell small batches or refill non-pressurized tanks, so you will have to rent bulk cryogenic containers, notwithstanding the low customer flow in your cryo center.
- A supplier may be located too far and, therefore, charge high delivery fees. In this case, it may be cheaper to rent a cryo cylinder, which does not require frequent refills.
That’s why it is crucial to find a local liquid nitrogen supplier and clarify their pricing and supply terms before you buy a cryosauna.
- Legal regulations in your country may restrict the use of large-volume cryo cylinders. For example, Italy and Switzerland require a powerful supply-and-exhaust ventilation system in the cryotherapy treatment premises, which may cost over 10,000 EUR to install. This forces the majority of cryopreneurs to opt for a Dewar-based cryosauna instead.