Talk:Turndown ratio

Could someone please show how one would mathematically go between these different turndown ratios instead of just showing some numbers? It would give more insight on how turndown is used.

For example (as already stated in the article):

The turndown for an orifice meter could be 3:1, with a nominal flow of 200 km3/day. Your max measureable flow is 300 km3/day and min is 100 km3/day.

In the next example a turbine meter has a turndown of 10:1

How do you find 60 km3/day to 600 km3/day mathematically in this example? Is this rounded in any way? The mid point (or nominal flow) for this turndown is 330 km3/day. How would one you relate the first nominal flow, where the turndown is 3:1, to this second nominal flow with a turndown of 10:1?

What I’m trying to say is that there must be an equation to go through these different turndown ratios, and it would be nice if it was stated.

Turndown Ratio

Turndown ratio is the ratio of maximum Flow to Minimum flow. Suppose maximum Flow Qmax=100 kg/hr and minimum Flow Qmin=25 kg/hr then the turndown ratio = (Qmax/Qmin)(100/25)=4. —Preceding unsigned comment added by 122.248.16.2 (talk) 07:31, 21 July 2010 (UTC)

I wonder if "rotary displacement meter" should be either a:

- rotameter but rotameter's work on the principle of variable area and not displacement. or a

- Positive_displacement_meter S243a (talk) 14:06, 18 April 2012 (UTC)

merge with Turndown ratio (boilers)
I believe the two articles should merge. The reason is because the term does not apply to boilers only, and also it does not apply to flow measurement and control only. It applies to any plant variable control system.--212.54.198.90 (talk) 10:31, 8 June 2012 (UTC)

By: M.M.L., PhD, Brownswerk Marine Inc. — Preceding unsigned comment added by 216.252.70.138 (talk) 15:57, 14 June 2012 (UTC) From: ASHRAE Handbook, HVAC system and equipment, 2012, p.13.4 "The turndown ratio for a source (Any device that can be used to heat or cool water under controlled condition can be a source)is different from that specified for a control valve. Turndown for a valve is comparable with valve rangeability. Whereas rangeability is the relationship of the maximum controllable flow to the minimum controllable flow based on testing, turndown is the relationship of the valve's normal maximum flow to minimum controllable flow. The turndown ratio of a source is defined as: Turndown ratio = 100 * Minimum Capacity / Design Capacity." — Preceding unsigned comment added by 216.252.70.138 (talk) 15:55, 14 June 2012 (UTC)

Copyright Violation
Most of this article is copied from https://sites.google.com/site/measurementsystems3/announcements. If somebody feels like removing the infringing content and leaving behind something that justifies an article, be my guest. Frankly, I think this entry is functioning as little more than a definition and don't regard a complete deletion for copyright violations as a bad thing. I will post it to the copyright vio list at the end of the week.VmZH88AZQnCjhT40 (talk) 23:43, 15 July 2013 (UTC)