physics

Hampson–Linde cycle

Hampson–Linde cycle is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hampson–Linde cycle rather than just read about it. In short: The Hampson–Linde cycle is a process for the liquefaction of gases, especially for air separation. William Hampson and Carl von Linde independently filed for patents of the cycle in 1895: Hampson on 23 May 1895 and Linde on 5 June 1895.

Key takeaways

Hampson–Linde cycle belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Hampson–Linde cycle to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Hampson–Linde cycle from memory before moving on to harder problems.

Reference excerpt

The Hampson–Linde cycle is a process for the liquefaction of gases, especially for air separation. William Hampson and Carl von Linde independently filed for patents of the cycle in 1895: Hampson on 23 May 1895 and Linde on 5 June 1895. The Hampson–Linde cycle introduced regenerative cooling, a positive-feedback cooling system. The heat exchanger arrangement permits an absolute temperature difference (e.g. 0.27 °C/atm J–T cooling for air) to go beyond a single stage of cooling and can reach the low temperatures required to liquefy "fixed" gases. The Hampson–Linde cycle differs from the Siemens cycle only in the expansion step. Whereas the Siemens cycle has the gas do external work to reduce its temperature, the Hampson–Linde cycle relies solely on the Joule–Thomson effect; this has the advantage that the cold side of the cooling apparatus needs no moving parts.

The cycle

The cooling cycle proceeds in several steps:

The gas is compressed, which adds external energy into the gas, to give it what is needed for running through the cycle. Linde's US patent gives an example with the low side pressure of 25 standard atmospheres (370 psi; 25 bar) and high side pressure of 75 standard atmospheres (1,100 psi; 76 bar). The high pressure gas is then cooled by immersing the gas in a cooler environment; the gas loses some of its energy (heat). Linde's patent example gives an example of brine at 10°C. The high pressure gas is further cooled with a countercurrent heat exchanger; the cooler gas leaving the last stage cools the gas going to the last stage. The gas is further cooled by passing the gas through a Joule–Thomson orifice (expansion valve); the gas is now at the lower pressure. The low pressure gas is now at its coolest in the current cycle. Some of the gas condenses and becomes output product. The low pressure gas is directed back to the countercurrent heat exchanger to cool the warmer, incoming, high-pressure gas. After leaving the countercurrent heat exchanger, the gas is warmer than it was at its coldest, but cooler than it started out at step 1. The gas is sent back to the compressor, mixed with warm incoming makeup gas (to replace condensed product), and returned to the compressor to make another trip through the cycle (and become still colder). In each cycle the net cooling is more than the heat added at the beginning of the cycle. As the gas passes more cycles and becomes cooler, reaching lower temperatures at the expansion valve becomes more difficult.

References

Further reading Timmerhaus, Klaus D.; Reed, Richard Palmer (2007). Cryogenic Engineering: Fifty Years of Progress. Springer. p. 8. ISBN 978-0-387-46896-9. Almqvist, Ebbe (2003). History of industrial gases. Springer Science & Business Media. p. 160. ISBN 978-0-306-47277-0. Maytal, B. -Z. (2006). "Maximizing production rates of the Linde–Hampson machine". Cryogenics. 46 (1): 49–85. Bibcode:2006Cryo...46...49M. doi:10.1016/j.cryogenics.2005.11.004.

Illustrations

Worked examples

Example 1 — a first encounter with Hampson–Linde cycle

Start with the simplest possible case. Write down what Hampson–Linde cycle claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hampson–Linde cycle before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hampson–Linde cycle ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hampson–Linde cycle

In research: Hampson–Linde cycle appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Hampson–Linde cycle in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Hampson–Linde cycle is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1895 in Germany, 1895 in science, Cryogenics, so understanding it makes those chapters shorter.
In everyday life: Look for Hampson–Linde cycle outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Hampson–Linde cycle in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hampson–Linde cycle means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Hampson–Linde cycle out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hampson–Linde cycle in simple terms?

Why does Hampson–Linde cycle matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hampson–Linde cycle?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hampson–Linde cycle.