Submersible transducer for ultrasonic cleaning

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CURRENT TOPICS

ensembles and from the Swarthmore Symphony Orchestra. All of this first-hand participation close to the material realities became distilled into his philosophical works; he was in continual demand as lecturer in this realm. Many are the organizations throughout the world which will suffer by his passing. In particular, the JOURNAL OF THE

FRANKLIN

INSTITUTE

owes

Dr. Swann a debt of gratitude for the faithful performance of his duties as an Associate Editor from 1923 until his death. He also served The Franklin Institute Laboratories for Research and Development as Senior Adviser-an activity to which he gave himself unstintingly. The Franklin Institute mourns the loss of this great colleague and friend. Submersible Transducer for Ultrasonic Cleaning.--A new submersible transducer which permits the adaption of any tank for ultrasonic cleaning has been announced by the Dynasonics Corporation of Syosset, N. Y. Conversion is made by simply placing the new device in the tank with no physical connection to the tank itself. Made of lead-zirconate which can handle high temperatures, the transducer is encased in a gasketed stainless steel housing and is available initially in a 250-watt rectangular size 7 X 8 in. It is effective in activating an area approximately twice that of the unit, thus the 250-watt unit is effective in activating up to a 5-gal. tank. When activated by the firm's recently introduced line of "Scatterblast" generators, the device may be used in multiples without the need for tedious matching of the additional transducers due to the generator sweep frequency operation. One advantage of the new transducer is that it makes it possible for the user to make a replacement with a spare unit in the few seconds re-

IJ. F. I.

quired to lift one out of the tank and trot another in. Once out of the tank the nnit may be repaired by removing the gasketed cover and reassembling. While a general "rule of thumb" calls for 100 watts per gallon of tank capacity, the manufacturer points out that the effective cavitation area of any ultrasonic cleaning device is in a specific area of the transducer and is increased or decreased by the density and surface tension of the solvent used. It is recommended that the installation be tailored to both the cleaning agent and the devices to be cleaned. It is expected the new device will be in demand by machine and plating shops, metal and machinery cleaning services, the automotive industry and for degreasing. Ultrareliable Tubes for Communications Satellites.--New ultrareliable "lighthouse" tubes for Project Advent communications satellites are being custom-built by General Electric to operate continuously for three years. Engineers at the company's Receiving Tube Department are taking extraordinary measures in the design and fabrication of the planar triodes to insure they will last for 25,000 hours in space. The work is being done under contract with the U. S. Army Signal Corps. The contract requires G.E. to supply the new tubes for use in tests and eventually in the operative transponders of the Project Advent synchronous satellite system. The Advent application calls for a number of the tubes in each of the system's satellites. The transponder in each satellite will be multi-channel. A feature of the tube which makes it appear unusual is its heat sink, a ring of oxygen-free high-conductivity copper. Lighthouse tubes designed for operation in the earth's atmosphere can use standard fin-type radiators for convection cooling, but for operation in