General Information

Serial #

16751

Part Number

1

Total Parts

1

AKA

N/A

Patents

N/A

General Description

synthetic casing, dial dasing, sliding door, controls and parts/ metal front plate, back, handle, parts/ rubber? feet

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

30.1 cm

Width

22.0 cm

Height

29.5 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Metrology

Category

Mass/weight

Sub-Category

N/A

Manufacturer

AKA

Cahn

Country

United States of America

State/Province

California

City

Paramount

Context

Country

Canada

State/Province

Unknown

Period

circa 1967+

Canada

An example of a European made balance used as a standard by a Canadian calibration service, GJS Mass Measurement owned by George Mihailov. George Mihailov worked at Industry Canada. In 1992 he left in order to start GJS Mass Measurement Inc. He ran the business out of his home. The business compared the accuracy of masses to secondary mass standards. Rather than sending their mass standards to the National Research Council Canada to be compared to Canada's primary mass standards, companies could use GJS Mass Measurement's calibration services. The uncertainty introduced by comparing to a secondary standard rather than a primary standard was not large enough to pose a problem. The equipment used in the business was often acquired through Crown Assets. This equipment was transferred to Fisher Scientific when it purchased the company. The motivation to purchase the company was that clients had been requesting that their balances be calibrated and, in purchasing the company, Fisher could provide a service. The purchase was also beneficial to GJS since it now had a much larger pool of clients. The sale took place in August 1999. At first GJS Mass Measurement continued to use its name and was a division of Fisher Scientific. Now it is simply Mass Metrology of Fisher Scientific, part of Thermo Fisher Scientific. This collection of balances (2006.0061 - 2007.0064) serves to tell the story of a small company which was started to fill a need and then was bought out by a much larger company when they too recognized the same need. Fisher Scientific metrology has a CLAS (Calibration Laboratory Assessment Service) certificate. The CLAS program is part of the Institute for National Measurement Standards, NRC. Fisher's working standards are calibrated in relation to their reference kilograms, which in turn are calibrated by NRC against the national reference kilogram. This gives indirect traceability, which can be done for the NIST reference kilogram too.

Function

A precision mass measuring device used by a calibration service to verify the accuracy of mass standards

Technical

To accurately determine the mass of a quantity of substance, the reading made by a balance must be made as accurate as possible. Having a balance calibrated measures its accuracy. The balance is made to a certain level of precision but this is useless if the balance is not accurate. This balance and its companions were used in calibration procedures. They were kept in the lab and the customers' calibration weights would travel to and from the lab. The thing that distinguishes the balances is their capacities, which would determine the size of weight they were able to accommodate. Cahn electrobalances were designed for use in gravimetric analysis in the micro and ultra-micro ranges. The sample is balanced by torque produced by a current in a coil within a magnetic field. The torque produced is exactly proportional to the current. The coil current is adjusted until the electromagnetic torque exactly balances the sample; the coil voltage is accurately by the precision potentiometer (Ref. 2). This Cahn electrobalance has a direct-reading digital readout weight dial in place of the standard ten turn dial, as illustrated in the 1971 Canlab catalogue (Ref. 2) as an option for Cahn gram electrobalances. The gram electrobalance was used to weigh analytical and production samples of up to one gram; small samples to an accuracy of 1/10 microgram (0.0001 mg).

Area Notes

Unknown

Details

Markings

raised metallic lettering on front plate reads 'MODEL G CAHN INSTRUMENT COMPANY PARMOUNT CALIFORNIA, U.S.A.' with functions for controls/ black lettering on instruction plate reads 'CAHN GRAM ELECTROBALANCE (R)/ with condensed operating instructions/ label on front reads 'Distributed and Serviced by/ FISHER SCIENTIFIC'/ plate on top for range switch is calibrated for 0 to 1g and 100 and is marked '16751'/ black printed label on front reads 'Cahn/ 16751'/ label on back reads 'MADE UNDER ONE OR MORE/ OF THE FOLLOWING PATENTS:/ U.S. 3,224,517 RE 26100/ UK 978,214'/ calibration label on top reads in part 'BALANCE CALIBRATION STATUS', 'Calibrated November 1, 1999' and 'G/S Mass Measurement/ A DIVISION OF FISHER SCIENTIFIC LIMITED'/ label on side reads 'OUT/ OF/ SERVICE'/

Missing

N/A

Finish

blue synthetic and painted metal casing/ black synthetic knobs and sial casing/colourless transparent door and dial casing window/ brushed metal plate with printed instructions/ black synthetic and grey painted metal controls/ red push button/ grey power cord

Decoration

N/A