Liquid Nitrogen Dosing Tips & Best Practices
As a brewer or coffee roaster, you are a master of your craft. You want to share your creation beyond the borders of your pub and coffee house. This makes canning or bottling inevitable. In doing so, it may become necessary to incorporate the use of a LN2 (Liquid Nitrogen) Doser.
什么是液氮剂量？它是真空绝缘，开放式大气，不锈钢储层，机械设计，用于管理LN2的两相流，并配有一个由PLC控制的致动阀，以提供编程和精确的液氮滴。听起来像一口？是的，但它是通过设计冷却TM值, no pun intended.
- 安全。这应该是你的第一个问题。当德aling with liquid nitrogen, you will be working with a cryogenic liquid at negative (-)320 degrees Fahrenheit which will cause frost bite on prolonged skin contact. Appropriate PPE or Personal Protective Equipment such as cryogenic gloves, safety glasses and face shield must be worn especially when setting up the system to start LN2 dosing. Once everything is all set up, and you’re not going to the touch the LN2 supply, there’s really no need to wear the cryogenic gloves as you won’t be in contact with extreme cold surfaces. However, definitely keep wearing safety glasses, not just for the LN2 doser, because it’s a smart, safe practice when operating a packaging line. Another safety concern is asphyxiation. At negative (-)320 degrees Fahrenheit, liquid nitrogen will be boiling, vaporizing to gas and expanding, which can cause asphyxiation in confined spaces. In the filling area, make sure oxygen (O2) monitors are in place and there is adequate air exchange. Provide Sub-contained Breathing Apparatus at the entrance if the filling room is a confined space. At the very least, ensure personal O2 monitors are worn by the operators. One should never compromise on safety especially with nitrogen gas as it is colorless so there is no way of visually detecting.
- Define what you need to achieve. What is it you are after? Your specific need defines the approach to successfully integrate LN2 dosing to your process. The following offers good advise on how best to achieve them:
- PRESERVATION. Shelf life extension through TPO reduction is achieved when oxygen in the head space of the can or bottle is diluted with large quantities of gas nitrogen molecules. Before we get into the details, let’s define TPO first. For TPO, the following formula applies:
TPO = DO + HSO
注意：溶解的氧气（DO）水平不同。啤酒或其他饮料中的DO水平是饮料从BRITE罐，输送，泵和填料拾取的O2的函数的函数。液氮给药仅影响顶部空间中的氧气的减少，从给剪液器或翻盖的最终密封点。因此，为了最小化O2拾取，必须采取其他方法，例如填充线路提供商推荐的其他内容中的氮气，输送和灌装过程。LN2给药的适当方式是实现顶部空间氧还原的方法是什么？一个必须在接缝剂或盖板的上游进一步剂量以允许液氮沸腾并在饮料的顶部膨胀。您还必须使用从外部元件的LN2保护开放容器，这可能会吹掉我们试图进入的N2气体。简单的Flexi-Glass在输送机上笼罩，其中开放式集装箱在装备器之间传播，帮助很多含有氮气分子。在上游进一步给药基本上为您提供了允许液氮沸腾和膨胀的时间。如果你没有装饰容器旅行的空间怎么办，让LN2煮沸？ This is when you use SoftDose™ Technology nozzles which facilitate the delivery of the liquid nitrogen dose in a spray pattern. This increases the surface area of the LN2 dose to accomplish quicker vaporization rates.
- 加压。凭借压力，罐子是施加的，允许更薄的容器壁和材料节省成本。特别是对于咖啡和其他非碳酸饮料，液氮给药是为了加压罐并允许其通过缝合器。为了达到罐中的压力，在最终密封件之前必须存在足够的液氮，允许LN2在接缝中煮沸，以构建所需的压力。只是小心不要放过太多的液氮来避免过度压力。通常，为了达到压力，必须将LN2更靠近缝合器。必须在每个罐中具有一致的填充高度或体积，以实现恒定的压力，因为该限定具有一致的顶空体积。如果您的顶空卷变化，则每个都会变化。变化填充高度的主要原因是填充阀和饮料溅出罐的错误校准。采取必要措施来避免和管理这些原因发生。 Equally essential to achieve constant pressure when you have constant fill height is to have the same quantity of liquid nitrogen inside each can at the time of seaming. Refer to the tips listed under Preservation to keep the N2 in the can. However, you have to understand the operation of your canning line. Most inline canning systems employ the use of multiple fill valves and one seamer. For this operation, a batch of 4 to 12 cans are filled at the same time traveling all together down the conveyor towards the seamer where each can is seamed one at a time. If all of the cans have been dosed with the same volume of LN2 then each and every can in the sequence will have less and less pressure as they wait their turn to be seamed. This is because the liquid nitrogen is continuously boiling and you are losing to evaporation. A solution for this is to administer incrementally increasing dose volumes of LN2 in each can in a cycle to compensate for the wait time. The end result is to have the same quantity of liquid nitrogen inside each can at the time of seaming. Some in-line canning systems have indexing wheels or worm gears that spaces the cans apart to achieve constant time from the LN2 dose to seaming. If this is the case then you must dose the same quantity of liquid nitrogen each time. Another scenario is the rotary canning lines. One important aspect to consider are line speed changes as it affects the timing from dosing liquid nitrogen to seaming. When you dose the same quantity of LN2 each time, and the line slows down, your final can pressures will be lower. Conversely, if the line speeds up, your final can pressures will be higher. Here is where a doser with Speed Compensation ability becomes essential, commonly known as Speed Compensation feature, it adjusts the dose volume upon detection of line speed changes. This is carried out by setting up speed sensors tied in with the time of release of the liquid nitrogen dose, managed by algorithms in the doser’s PLC. For this section on Pressurization, we focused on aluminum cans. However, the same considerations also apply to aluminum bottles, PET bottles, PET cans, and other packaging types which need internal pressure from liquid nitrogen dosing.
- 完美的倒™与氮化作用。工艺啤酒s like to tell their story with their product. To reach more customers they use cans, and with a can, the discerning consumer expects the perfect pour with a nice cascade and fine bubbles. Beyond the preservation, consumers also seek that perfect pour experience they get from the tap in a can. The dosing of liquid nitrogen can help, and it’s necessary for both widget and non-widget cans. Nitrogenation is what gives the consumer the same great taste and mouth appeal from a can which they traditionally get from a product poured out of the tap. How is the “perfect pour” achieved? Let’s consider a Milk Stout beer. With the can popped open, the nitrogen is released. The beer is poured and you will see the CO2 foaming action. As the bubbles rise to the top, the cascade is formed…that is a “perfect pour”! Carbon Dioxide (CO2) is part of the perfect pour, and it’s enhanced by liquid nitrogen dosing. Here is the science behind the perfect pour. With pressurized nitrogen gas in the headspace of a closed beer, the CO2 in the beer stays dissolved. The partial pressure of the nitrogen prevents the CO2 bubbles from forming. When the can is opened that nitrogen gas pressure escapes, and the CO2 can now bubble to the surface of the beer. This creates the much sought-after beer cascade or the “perfect pour”. The foamy cascade comes from the bubbling CO2 and proteins from the barley. Some of those proteins have “hydrophobicity”. This is like being allergic to water. As the CO2 bubble races for the surface, these proteins hitch a ride and bind to the bubble to avoid the water. The bubble bulks up, resulting in the cascading foam. Different proteins create different foam characteristics. Some coat the bubbles. Others make the bubbles more rigid or sticky. It all comes down to the qualities of the barley. Beer connoisseurs say a beer tastes better with a creamy cascade, partly due to the smooth texture, but also from the aromas which are pulled out of the beer as the bubbles percolate to the top. Depending on your specific objective or objectives, read further along and we will define best practices to optimize your LN2 doser.
- Optimize your Liquid Nitrogen Doser selection. The addition of any equipment to your canning or bottling line is a good investment to achieve a variety of new product offerings. Just like any investment, it’s in your best interest to optimize it. A good understanding of the following will help achieve this:
- 电源：110-240 VAC，50/60Hz，110 W
- Care for your Liquid Nitrogen Doser. Now that you have your LN2 dosing system figured out, here are things to recognize and consider for long-term use and a trouble-free operation:
- Purging: Moisture does not go well with liquid nitrogen. At negative (-)320 degrees Fahrenheit, moisture will instantly freeze in contact with LN2. Using GN2 is critical when purging. Anything other than GN2 may result in adding more moisture into the dosing system which may lead to ice formation, and ultimately blockages preventing the system from functioning properly. Purging with warm or hot GN2 is always preferable to cold GN2. Results are seen quicker as hot GN2 can vaporize moisture. Make it a standard operating procedure to always purge prior to starting up the system. NOTE: All cryogenic equipment such as the Liquid Nitrogen Doser requires purging to get rid of moisture from the environment.
We hope sharing this knowledge supports your decision to get started with liquid nitrogen dosing. Clearly, there is more to share and cover beyond this article.
Please visit our websites to download any of our educational webinars and literature: www.ChartDosers.com and/or www.DitchTheWidget.com
Until next time!!!