Talk:Zippe-type centrifuge

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Untitled[edit]

  1. The speed of sound is not measured in revolutions per second
  2. If it runs in a vacuum then the speed of sound is meaningless anyway

Neutrality?[edit]

Too much hate of USSR detected. I realize that US intelligence works hard to demonize USSR but this article exceeds the reasonable limits. It is next to impossible to force scientists to work. The fact that German scientists get ahead of their colleagues in USA means that USSR created great working environment for German researchers. For comparison, according to Wikipedia http://en.wikipedia.org/wiki/Wernher_von_Braun von Braun had a "US army career", although he was effectively a forced labor (hence, US felt behind in the space race). Similarly, Germany or USSR "annex and invade", while UK or US "join territory to commonwealth" or "bring democracy". Nice use of Newspeak. Great job, Airstip 1.

Correction[edit]

Jeff Knaggs 12:07, 1 Jan 2005 (UTC)

You are correct, I removed it. Edward 12:24, 2005 Jan 1 (UTC)

A washing machine is a centrifuge, that's why it was used as a comparison. A hard disk isn't a centrifuge. Edward 13:32, 2005 Jan 2 (UTC)

Yeah - only thought of that after submitting the hard disk change. You can change it back if you want. I just felt that more people online would be able to relate to hard disk speed than to washing machine speed.. AndrewH 15:07, 2 Jan 2005 (UTC)

"If we assume a rotor diameter of 20cm (actual rotor diameter is likely to be less), this corresponds to a linear speed of greater than 2 Mach (1 Mach = 340m/s). For comparison, automatic washing machines operate at only about 12 to 25 revolutions per second during the spin cycle."

This isn't a helpful comparison at all. In order for this to be meaningful, the comparison should be expressed in the same terms. The rotor and washing machine should either both be expressed in RPMs or in meters per second. Winick88 (talk) —Preceding undated comment added 05:51, 30 November 2010 (UTC).[reply]

A gas centrifuge runs around 80,000-100,000 RPM, vs 800-1000 RPM for a washing machine (during the spin cycle only). The linear speed can be obtained by using the formula linear_velocity=radius X angular_velocity or linear_velocity(cm/sec) = radius (cm) X RPM X 2.65 X 1e-3

In terms of angular velocity, the gas centrifuge is about 100 times faster. In terms of the linear velocity at the edge, it is only about 30 times faster.chami 09:08, 24 July 2011 (UTC) — Preceding unsigned comment added by Ck.mitra (talk • contribs)

The forces inside of one of these things are equivalent to how many gees? --Juuitchan?

I did some basic calculations and came up with around two million times the acceleration of gravity! Maybe someone can double-check this. Anyway, assuming 1500 revolutions per second and a radius of about 0.2 meters (they're actually quite small, from what I've found), plug that into a = v^2/r = (2*pi*r*revs)^2/r = 1.8e7_m/s^2. The acceleration of gravity is about 9.8_m/s^2, which gives the final result of about 1.8e6 Gs. HorsePunchKid 16:01, 2005 Apr 20 (UTC)

What is the difference between the Zippe type and other gas centrifuges? (Maybe need a merge)[edit]

What is the difference between the Zippe type and other gas centrifuges? (Maybe this article needs to be merged into the gas centrifuge article?) Lchiarav 06:30, 28 November 2005 (UTC)[reply]

My recollection from the sources is that magnetic bearings and use of a vacuum were his major innovations, together with fine engineering. This extlink tells more. I'm not pro-merger, but there could be more clarification. I do wonder if Gas centrifuge should be more generic, rather than just about uranium isotope separation. - Rwendland 10:48, 29 November 2005 (UTC)[reply]

Magnetic bearings perhaps; I cannot verify. But using vacuum to reduce friction is common in all ultracentrifuges. I believe it is the tweaking the designs. The resonance is also a problem that was taken care (??) Ck.mitra (talk) 14:24, 5 January 2010 (UTC)[reply]

When a gas is centrifuged, at high speed the pressure at the walls is high and the pressure at the axis is low. Compare the atmosphere, the pressure at the surface is high and the pressure at higher altitudes decrease logarithmically. A temperature gradient also contributes to the enrichment process. Taking the preceding analogy, we have a difference of temperature on the land and the sea surface, which gives rise to a air flow but the moisture (lighter fraction) rises to the top. In addition, there is another force called coriolis force (responsible for storms, cyclones, tornadoes etc) which cannot be neglected (in fact this is an important aspect in the whole isotope enrichment).

The ideal place for input stock to be introduced is somewhere in the middle (of the axis of the centrifuge) close to the axis. The light fraction should be taken off from the top (of the axis of the centrifuge) somewhere in the middle (medium pressure region). Similarly the heavy fraction should be taken off near the bottom (of the axis) closer to the periphery. The amounts are withdrawn depending on some steady state formula.

It is not correct to state "The lighter U-235 collects in the center".

The gas centrifuge is a basic engineering problem. The article lacks these attributes. The bearings and the acoustic resonance aspects are not clearly dealt. Ck.mitra (talk) 17:39, 9 April 2010 (UTC)[reply]

Washing machines operate at 15 RPS?[edit]

I find it extremely doubtful that a washing machine rotates 15 times every second. Where is this factoid sourced from? Perhaps it would be prudent to qualify that with something along the lines of "during the spin cycle". 24.118.114.210 17:56, 13 April 2006 (UTC)[reply]

The New York Times says:
A washing machine on spin cycle is a centrifuge, its whirl creating artificial gravity that separates water (heavy) from clothes (light).
A good washing machine spins about 15 revolutions per second.
Edward 18:18, 13 April 2006 (UTC)[reply]

A washing machine on a fast speed ("1000 RPM") is about 15 RPS- during the spin cycle. However, clothes are heavy and water is light. No proof needed: most clothes sink in water. Cotton and most synthetics have a density of around 1.2 (approx value; depends on the processing).

Basic idea of centrifugation is not applicable in a simple washing machine during the spin cycle. Everything is pressed on the perforated wall and water is basically squeezed out by the centrifugal force. It is more like filtering rather than sedimenting... —Preceding unsigned comment added by Ck.mitra (talk • contribs) 07:43, 27 July 2008 (UTC)[reply]

What is the actual cost of a centrifuge?[edit]

== How many in a series fo centrifuges are needed for the two levels of enrichments? ==about 1000-10000: can be improved with feedback. If performance is poor, then you need more.Ck.mitra (talk) 08:18, 27 July 2008 (UTC) --Falazar 13:39, 27 October 2006 (UTC)[reply]

Selveral hundred Hz?[edit]

The article states: The AC motors which drive the centrifuge require higher than normal frequency AC, and the several hundred Hertz AC is detectable by other countries SIGINT ELINT. This sounds wrong. "Several hundred Hz" is not a very high frequency, particularly for a centrifuge that itself spins in the kilohertz range. If "several hundred thousand Hz" is meant, it is easier to believe that it will radiate detectably, but still difficult to see how such an emission could be identified as a centrifuge in operation with any certainty (for example, the horizontal sync of high-end computer monitors will have their low harmonics in this range). Anybody know what is actually intended to be said here? Henning Makholm 22:21, 12 December 2006 (UTC)[reply]

Even if it would be identifiable, it would be easy to shield it by a faraday cage.Errorneous 15:00, 18 July 2007 (UTC)[reply]

You will need 1-5 KHz high power sources. Not really high frequency and causes no significant problems. You start with the lower frequencies to start the centrifuge. These are low frequency that can inject back into the power lines. These low frequencies are relatively messy to shield. Basically the chamber will act as a huge antenna with megawatts of power ... But they are in the range of lower audio frequencies.Ck.mitra (talk) 08:18, 27 July 2008 (UTC)[reply]

washing machine analogy[edit]

loved it. Decora (talk) 12:22, 6 October 2009 (UTC)[reply]

Poor Reference[edit]

Ref #2 was linked to a BLOG.[1] This is not good. Blogs are not reliable sources. The blog itself referred to a Washington Post article so I wonder why that was not used as the reference? The reference also had no date, source or title(like 1. below), Very Un-encyclopaedic! I have linked to the Washington Post article, which does not mention the bit about fingerprints being enough to unbalance the cetrifuge, though it is possible. [2]

  1. ^ [1]
  2. ^ Linzer, Dafna & Moore, Molly (April 28, 2006) U.N. Agency Finds Iran Noncompliant Washington Post

Forgot this!—220.101.28.25 (talk) 13:42, 12 February 2010 (UTC)[reply]

I do not believe the "fingerprint" story. However, UF6 is quite corrosive and fingerprints can induce corrosion. Extensive corrosion can lead to catastrophic failure. This is particularly likely if the rotor is made of aluminum.Ck.mitra (talk) 15:55, 13 April 2010 (UTC)[reply]

Seal between rotor and static comonents[edit]

Does anybody know how the centrifuge is sealed at the top to prevent UF6 from escaping into the vacuum outside the rotor?. I'd imagine at 90000 RPM friction would be a no-no , so how is it done? Does it simply rely on the high RPM generating a low pressure near the axis and then pump out any UF6 that escapes, or is there some more ingenious design? 95.109.104.4 (talk) 18:49, 25 October 2010 (UTC)[reply]

When the centrifuge is at full speed, the pressure gradient created is sufficient to have practically vacuum near the axis. Dolorpiedo (talk) 09:35, 22 January 2023 (UTC)[reply]

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Scientists? What scientists?[edit]

"After the scientists were released from Soviet captivity in 1956..." The article makes no previous mention of scientists. Who were they? Why were they in captivity? What were the circumstances of their release? 79.73.150.27 (talk) 02:28, 11 August 2016 (UTC)[reply]

How to avoid shock waves?[edit]

The UF6 hits the scoops collecting the enriched and depleted fractions at much above sonic speed. Supersonic shock waves, propagating in the gas, would propbably destroy any separation. The scoop for the heavier fraction is behind a perforated baffle, which probably prevents propagation of the shock waves. But the other scoop is everywhere drawn without baffle; it is intended to slow down gas rotation locally, hence reduce the radial pressure gradient and thus induce the countercurrent. Does anybody know, how shock waves are avoided there? Maybe they use a modified (perhaps only short) baffle? Dolorpiedo (talk) 10:12, 22 January 2023 (UTC)[reply]

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