The Stroboflow, An Oscilloscope for Hydraulics.--The Stroboflow, for reproducing desired rates of flow in liquids, comprises a precision-made turbine, mounted on stainless steel pivots in Graphitar bearings between transparent panes, and allowed to rotate, practically floating in synchronism with the liquid.
The rotational speed of the turbine is used as a measure of the quantity of liquid flowing. Since there is a straight-line relationship between the speed of the rotor and the quantity of the liquid, and since the Stroboflow provides a very precise means of determining rotor speed, these two factors are combined in this instrument and constitute a highly accurate method of flow-rate indication.
โข The rotor's speed is determined from the stroboscopic effect of light viewed through an aperture in the turbine disc. The number of virtual images so obtained is a measure of the rotational speed, which in turn is directly proportional to rate of flow. The Stroboscope is calibrated in terms of stationary patterns of these images. Once a predetermined pattern is established, indicating a desired rate of flow, any deviation however minute from this rate of fow, will cause the pattern to precess.
One of the outstanding features of Stroboflow operation is the means by which the range is extended without sacrifice in the degree of accuracy. This is accomplished by a simple change of jets, interchangeable in any Stroboflow without change in calibration. Five standard jets, supplied with each instrument and for which each instrument is calibrated, provide forty different rates of flow in one instrument.
Since the rate of flow, the speed of the rotor, and the jet characteristic are all in direct, linear relationship over the entire range of the instrument, it is practicable to adapt several, separate Stroboflows to indicate different rates of flow while exhibiting identical patterns. This simplifies monitoring of flow rates in processes requiring coordinated multiple flows.
R. H. O.
Rocket Motor Test Stafion.--A test station which will static-test rocket propulsion motors up to 50,000-lb. thrust, equivalent to 500,000 hp., has been constructed near Schenectady.
This test station, the first of its kind, has been in operation for over a year, contributing invaluable data for basic rocket-motor design and fuel development.
The test station has three heavily-constructed steel-re-inforced concrete rocket-motor static-test pits. Each pit is set into the forward slope of a small hill, and earth is mounded around its sides.
Three covered stairways lead down into the interior of the test pit, which is divided into four rooms; control room, motor room, and two reactant rooms. Three-foot steel-re-inforced concrete walls separate the motor room from the rest of the structure, while all other walls and the roof are 2 ft. in thickness. Heavy steel doors seal off each room when tests are in progress. I83