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Hydrogen Properties for Energy Research (HYPER) Laboratory Cool. Fuel.

Cryogenic Seals using Indium

Finding a way to seal small, mobile molecules such as hydrogen and helium at cryogenic temperatures can be quite difficult. Most common seals break down at such cold temperatures, and even a tiny leak path can be catastrophic when working with flammable gasses and temperatures that can freeze the oxygen right out of the air. Luckily, we have wonder element 49: Indium. High purity indium has a lower melting point, and hardness than lead, making it malleable enough to be an effective sealing material. In addition, at high purities, indium readily pressure welds to itself, and bonds to other metals, glass, and ceramics.

In the … » More …

Cleaning Helium Compressors

The helium compressor that drives a cryocooler has to effectively reject the heat it’s removing from the helium stream to prevent itself from overheating, and keep the cryocooler cooling efficiently. In most cases, this means running a heat exchanger with a cooled water loop to keep everything cool. This can be very effective when you’re running high purity, clean water through the heat exchanger, but dirty, rusty, or impure water can reduce performance and foul the heat exchanger tubes. In the lab, we use a cooling loop independent from the building water paired with a water filter to help keep water as clean as possible … » More …

Making a Cryogenic-compatible O-ring seal

One issue that I ran up against while re-designing CHEF for my thesis research was the connection point on the hydrogen liquefaction tanks. I decided to use VCR connectors because of their reliability at vacuum and low temperatures, this meant that a VCR connection directly to the tank would be easiest for design and build. As all VCR connections, off the shelf, are made of stainless steel, and the liquefier tanks were made from Aluminum (because of thermal concerns), welding a connector directly on was not an option. NPT connections were another possibility, but ultimately not chosen for fear of leakage at low temperatures. Luckily, … » More …

DI water change for cryo-cooler cooling loop

Follow these steps to change the DI water in the cryo-cooler cooling loop every 6 months, and the filter every 12 months. Remember: a happy cryo-cooler means a happy researcher!

To change the water:

Open drain valve to allow water to drain into floor drain. Use a hose to make sure that water flows down drain. (warning: make sure water goes ONLY into a drain or water damage to lower rooms may occur)

Allow line to drain till water is no longer continuously flowing (pump may be turned on to ensure all water is vacated)

Close drain valve
Change water filter … » More …

Compressed Gas Bottle Safety

Compressed gas bottle safety is important! Follow these simple rules to ensure your gas bottle stays a container – not a rocket.

Bottles should be chained at all times to prevent them from tipping over.
Steel caps need to be on bottles when not in use – especially for transportation.
Transport gas bottles on bottle carts.
Always use pressure relief devices when attaching high pressure bottles to systems.
Ensure lines are depressurized and bottle valve is shut before disconnecting the bottle from a system – even when the bottle is “empty”.
Flammable gas bottles should always be grounded before … » More …

Musings of a Cryogenicist: Day 5 – Vacuum Gauges (everything you wanted to know and more!)

In my last post I talked about the 3 main types of Vacuum gauges available for use. They were:

Force measuring (105 – 10-2 Pa)
Heat transfer (10 – 10-2 Pa)
Electrical charge transfer (ionization) (100 – 10-9 Pa)

I also talked about how I have a FRG-700 Inverted Magnetron Pirani Gauge currently connected to my Cryostat chamber. Well now I want to look at each of these types of vacuum gauges in a little more depth giving the general method of vacuum measurement for each. Understanding how each of these work at a basic level and their limitations can be … » More …

Musings of a Cryogenicist: Day 4 – What’s in a Vacuum?

So what IS in a vacuum? Nothing? Something? Everything?! Well first we need to define what a vacuum is. In day to day life we consider any gas that has less pressure than its surroundings to be in a state of ‘vacuum.’ That doesn’t mean that it has NOTHING in it, it just really means it has less in it. So what’s a good practical example of this? A vacuum cleaner: it produces an area of lower pressure than the surrounding atmosphere giving it the ‘sucking’ capabilities that we use to clear an area of dirt or dust. Now I assume that most people know … » More …

Musings of a Cryogenicist: Day 3 – Interior Components

Alright, so you have a test chamber, you have a vacuum pump (I’ll get more in depth into in a future post), and you have a cryocooler. Now what? Well now we get down to the nitty gritty, now it’s all about designing the experiment itself. First you need to figure out what kind of measurements you need, and what other peripherals are necessary. In my case, so far I have figured that I need thermocouples for temperature measurements and fiber optical cable rated at cryogenic temperatures for my Raman Spectroscopy measurements. I also need some wires to run to my heater so that I … » More …

Musings of a new Cryogenecists: Day 2 – The test chamber

The test chamber may not be the most technically challenging or complicated part of the cryo-design, but it is arguably the most important. Without it, you have no chamber to pull a vacuum on, no enclosed boundaries for your cryocooler to take energy from, and nothing to mount your experiment to. Luckily I am inheriting an already functioning test chamber from Jake Fisher. As I noted in the first post, you must balance time, cost, and ease of design. This means that while I could design a completely new test chamber that fit the specifications for my experiment exactly, … » More …