Humboldt State University ® Department of Chemistry

Robert A. Paselk Scientific Instrument Museum

 
From : Braun-Knecht-Heiman Co., Catalog No. 40 Laboratory Instruments Apparatus Supplies, Braun-Knecht-Heiman Co. (1940) pp. 31-3.
 
Courtesy of the VWR Scientific Corporation
 

LABORATORY BALANCES

CHRISTIAN BECKER ANALYTICAL BALANCES

MODERN industry demands modern equipment. A little calculation shows that the average chemist spends a significant part his working time at the Balance. Chemists are frequently seen in the laboratory waiting for their turn at a Balance, holding up important work to make a necessary weighing. The necessity, therefore, of a rapid, convenient and accurate Balance is evident.
 
Recognition of the importance of the Balance is given in the following listings, which include a Balance for practically every purpose. In most cases, the Balance is offered both in the conventional rider type and in the Chainomatic type. Particular attention is directed to the Chainomatic Balance, the use of which gives many days extra working time in the course of a year.
 
The Chainomatic Balance has the usual construction of Analytical Balances except that all weighings from 1/10 mg. to 100 mg. are made by adding or decreasing weight on the beam by means of a perfected chain. The length of chain supported by the beam is increased or decreased, thereby changing the weight carried by the beam, by rotating the crank at the right side of the case.
 
 
This can be done while the beam is swinging and the case closed, resulting in an enormous saving of time when compared with the handling of small weights and riders and the opening and closing of the glass door. Direct readings are made from the graduated dial or column and vernier.
 
Dial-Reading Chainomatic
 
The Dial-Reading Chainomatic Balance makes use of a revolving graduated dial to lengthen or shorten the effective length of the chain. The chain is attached to the revolving dial while the vernier remains stationary. The dial is revolved by means of the crank at the right of the case. All readings are made at eye level, reducing parallax to a minimum. Graduated dial and vernier read from 1/10 mg. to 100 mg.
 
 
Column Chainomatic
 
The Column Chainomatic Balance makes use of a graduated vertical column and vernier. The chain is attached to a hook on the vernier. The vernier moves up and down the graduated column when the crank is rotated. Graduated column and vernier read from 1/10 mg. to 100 mg.
 
Movable Index or "Auto Dex"
(Patented)
In adjusting the equilibrium of an analytical balance, it is customary to do so by means of the adjusting nut at the end of the beam. This necessitates raising and lowering the front sash several times and is liable to introduce an error owing to the warmth of the hand when handling the beam. With a Becker Balance equipped with a movable Index (Auto-Dex), controlled by a thumb wheel at the left front of the balance case, a slight turn of the thumb wheel moves the index plate to left or right as necessary until the indicator is coincident with Zero. This method saves time, eliminates the necessity of touching the adjusting nut, and greatly increases the life of the agate edges.
 
Beam Arrest (Releasing Mechanism)
The beam arrest arms and the beam being pivoted about a common axis, the supporting points of the arrest arms move through the same arc as the supporting points of the beam so that contact between edge and bearing always remains the same, thus reaching the acme of balance construction, the shifting of the end bearings with the consequent dulling of the agate edges being completely eliminated.
 
Advantages of Magnetic Damper
Becker Analytical Balances, both Rider and Chainomatic, can be supplied with built-in Magnetic Damper. The particular advantages of the Magnetic Damper are:
 
1. Brings indicator (pointer) to rest almost immediately.
 
2. Does not affect the sensitivity of the balance.
 
3. Unnecessary to calculate the rest point by the swing method.
 
4. Greater rapidity in weighing. Some operators estimate a saving of approximately 50% in time.
5. The magnet can be lifted instantly from the metal plate, permitting the balance to be used without any damping action if so desired.
 
Equilibrium Adjuster for Column Chainomatic Balances
(Patented)
This device makes use of the chain to obtain equilibrium without using the adjusting nut at the end beam. With the 0 of the vernier and the 0 of the graduated column coincident, the vernier hook carrying the chain can be made to move up or down by means thumbscrew on the top (outside) of the case, until equilibrium is obtained. This can be done while the beam is swinging and the case closed, resulting in a great of time and saving the agate edges.
 
Equilibrium Adjuster for Dial Reading Chainomatic Balances
(Patented)
The balance is brought to perfect equilibrium quickly by means of the crank at the right of the case. The zero of the vernier is then made coincident with the the dial. The vernier movement is controlled by a small knob at the right of, and near the top of the case. This is done quickly while the beam is swinging and the case closed, resulting in a great saving of time, and saving the agate knife edges.
 
Equilibrium Adjuster for Analytical Rider Balances
(Patented)
This device, which is standard equipment on all Becker Analytical Rider Balances, makes use of a chain to obtain equilibrium without using the adjusting nut at the end of the beam. The hook carrying the chain can be made to move up or down by means of the thumb screw on the top (outside) of the case, until equilibrium is obtained. This is done while the beam is swinging and the case closed, resulting in a great saving of time, and saving the agate edges.


 

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Last modified 22 July 2000