# Gas-Liquid RO — Restriction Orifice Calcs

> Restriction Orifice Calcs (iPhone/iPad app by Bjarne Berge.)

- Source: https://appshunter.io/ios/app/gas-liquid-ro/id1374664837 (this page in markdown: same URL + `.md`)
- Developer: [Bjarne Berge](https://appshunter.io/developer/1209858941)
- Category: Productivity, Utilities
- Price: $0.99 (on sale, was $6.99)
- Age rating: 17+
- Requires: iOS 15.6 · 1 MB
- Languages: American English
- Released: 2018-04-23
- Data updated: 2026-06-01
- User reviews in markdown: https://appshunter.io/ios/app/gas-liquid-ro/id1374664837/reviews.md

## What is Gas?

Gas-Liquid RO calculates gas and liquid restriction orifice sizes and flowrates based on R. W. Miller's "Flow Measurement Engineering Handbook".  
For gases this means that sonic velocity (critical flow) exists at the orifice throat, and further decrease in the downstream pressure will not increase the mass flow rate.  
For liquids, choked flow occurs when the orifice decreases the downstream pressure to below the liquid vapor pressure, at that point the liquid will partially flash into bubbles of vapor.  If vapor pressure is less than downstream pressure (non-choked flow), the pressure drop is calculated based on empirical equations used for control valves.

## Chart rankings

- #186 in Top Paid · Productivity (US App Store)


## Version history (last 5 releases)

### 5.0 — 2026-01-26

Updated with Xcode 26.
Bug fixes.

### 3.2 — 2022-03-08

Updated to IOS 15.

### 3.1 — 2021-02-12

Upgraded to latest IOS-version
Added 'Share' button to enable sharing, saving, printing of results
Changed color-scheme to work in Dark Mode
Updated layout and fonts to work better with iPads (better layout/larger fonts)

### 2.0 — 2019-05-19

Updated version includes liquid calculations (Crude Oil, Water, Methanol, MEG, DEG and TEG) in addition to gases (Natural Gas, Nitrogen and Air).
Bug fixes.

### 1.0 — 2018-04-20

No release notes.

## More apps by Bjarne Berge

- [Gas-Liquid Leak](https://appshunter.io/ios/app/gas-liquid-leak/id1209858942)
- [AGA-3 Orifice](https://appshunter.io/ios/app/aga-3-orifice/id1350504597)
- [ISO-5167](https://appshunter.io/ios/app/iso-5167/id1356345079)
- [Line-Fit](https://appshunter.io/ios/app/line-fit/id1448053643)
- [Curve-Fit](https://appshunter.io/ios/app/curve-fit/id1450077815)

All apps by Bjarne Berge: https://appshunter.io/developer/1209858941

## Related topics

[bjarne berge](https://appshunter.io/ios/topics/bjarne-berge)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-01.*