Full Details

Name and Model Number Kellog Equilibrium Flash Calculator
Country of Origin USA
Date of Manufacture  
Front Scales I-VII, f(M,K) =M
Back Scales  
Scale Length 10 ins
Type of Rule Slide Chart
Construction Cardboard, plastic cursor
Area of Use Chemical
Comment This is a specialized calculator, which allows process engineers perform equilibrium flash calculations.
MW Kellogg is now KBR, and has a history in developments related to the oil and gas industry industry.
Rarity RR
Donor Collection of Wayne Harrison
Match Number 406
(Click Picture for Details)

In conjunction with our 'donors' we assign a rarity rating to each item, based on the system devised by Herman van Herwijnen
(1929 - 2004), renowned Dutch collector, author, and creator of Herman's Archive, a collection of 5,000 slide rule images on CD.
• RR = Rare - 1 of 25 collectors has one; it may take a year to find an example in the marketplace.
• RRR = Very Rare - only a few known to collectors; may be several years before it comes up for sale.
• RRRR = Extremely Rare - a museum piece; unlikely that an example will come up for sale.