A New Shaking Device for the Chemical Laboratory

Posted By Richard Jefferson on 02 December 2014

Posted in The Vintage Machinery Almanac

This article was originally published in Electrochemical and Metallurgical Industry Publication of July 1907. Information within this article is therefore correct as of 1907. The publication of this material aims to provide historical insight on the subject and its place in industry.

The alchemist of old failed in his search for the philosopher's stone, whose contact with the baser metals was to transmute them into the desired gold and silver. Nor has the later day chemist, for obvious reasons, found this magic pebble, but he has found the secret of changing the baser oxides into the equivalent of gold and silver. And when we compare the laboratories of the present day with those of the ancients, with their meagre supply of crude reagents, and whose apparatus included only forge-like furnaces and retorts, we cannot but marvel at their persistency in the face of such difficulties and the wonderful results they obtained.

In those days the laboratory was more like a forge shop, now it is approaching more and more to the mechanical, with its automatic samplers, grinders and stirring machines doing the manual labor, leaving the operator free for the more delicate manipulations. In the present day equipment to keep pace with the ever-increasing demands of the mills and furnaces, one is called upon to use every facility whereby quickness and accuracy may work together towards the accomplishment of the best results.

Among the various pieces of apparatus going to make up the equipment of the modern laboratory it is the purpose of this article to describe the latest appliance, in the shape of a laboratory shaking device. It was designed and is particularly adapted for the purpose of hastening the precipitation of phosphorus by the well known and almost exclusively used molybdic acid method. But is equally useful where agitation is desired in a flask for either dissolving or precipitating. It consists of a frame supporting a vertical shaft, which is revolved by a 6-inch pulley wheel. The upper part of the shaft is bent slightly from the perpendicular. Encircling the bent portion of the shaft is a hub, which in turn supports a flat disc on which the flasks to be shaken are attached. The hub and disc are prevented from turning, when the shaft is revolved, by suitable teeth on the underside of the hub, meshing into corresponding teeth on the top of the supporting frame.

The laboratory shaker can be best likened to the simultaneous pitching and tossing of the deck of a ship in a tumultuous sea. With each revolution of the shaft a wave travels around the flask or flasks, and by increasing or diminishing the number of revolutions the intensity of the wave movement is controlled.

To obtain the maximum agitation and still retain the solutions in the flasks, without corking, from 100 to 140 r. p. m. has been found very satisfactory. The disc is made to hold six flasks, any one of which can be placed in or removed from the machine in a fraction of a second. The gripping device is movable, up or down, enabling it to be quickly adjusted to hold any size flask from a 6 to 24-ounce.

Heat can be applied to the apparatus if desired by means of a circular burner, but it has been found that by adding the hot liquid to the flask, or heating the contents of the flask before placing it in the machine, the same end is obtained.

Advantages being that during the time of shaking the operator can be doing other more profitable work, with the assurance that aside from being relieved from the fatigue of the operation the machine is not shirking the job, resulting in false analysis, while with the machine the reverse is the case, it is always allowed to do its full quota of work. Then under its constant conditions, in phosphorus precipitation for instance, a precipitate of like crystallization is always obtained, aiding materially its estimation by judging its bulk, as is the practice in most busy open-hearth steel works laboratories.

Too much cannot be said in praise of the laboratory shaker, its simplicity, ease of operation, quietness and the readiness with which the flasks can be placed in and removed from the apparatus, and the fact that the flasks do not need to be corked with the trouble that entails, will commend it to anyone. Application has been made and the claims granted for a patent covering the ideas embodied in this machine.

Image Credit: SMU Central University Library