Abstract: Polymers of relatively high bulk density are produced at a satisfactory rate by polymerization carried out as a gas phase polymerization, in which the monomers are contacted with the catalyst composition in the substantial absence of a liquid non-polymerizable diluent. Comparison of polymerization in liquid phase and in gas phase polymerization shows that when for both polymerizations the temperature is lowered to achieve the same increase in molecular weight, the gas phase polymerization shows a considerably smaller loss of reaction rate and bulk density. It has further been found that when polymers of the same molecular weights are prepared in both gas phase and liquid phase polymerizations, the rate at which the polymers are produced is higher in the case of the gas phase polymerizations, and, in addition, the gas phase prepared polymers have higher bulk densities.

Abstract: A fluid mass flow meter that responds rapidly to changes in the rate of flow of a fluid and that is insensitive to variations in ambient temperature. The flow meter has a thermal clamp that clamps the sensor tube adjacent the extremities of a sensor disposed along the tube; a frequency compensating amplifier that, in cooperation with the thermal clamp, increases the frequency response of the meter; and an offset null bias circuit that, in combination with a bridge balancing potentiometer, corrects for the effects of variations in ambient temperature.

Abstract: A solenoid which has a coil, a ferromagnetic core extending completely through the center of the coil and a ferromagnetic upper pole formed integrally with the core at the lower end of the coil. The upper pole having a diameter larger than the diameter of the core but smaller than the outer diameter of the coil. A plunger mounted for movement towards and away from the upper pole. The plunger is operably connected to a mass flow control valve and spring biased towards a closed position away from the upper pole. The plunger has a diameter greater than its length and a set of concentric cylindrical ridges extending downwardly to interleave with a corresponding set of upwardly extending concentric cylindrical ridges on a lower pole. An outer, square ferromagnetic casing completes the magnetic circuit by extending from the upper end of the core to the outer surface of the lower pole. The interleaving ridges provide a large surface area for transfer of magnetic flux from the lower pole to the plunger.

Abstract: There is shown and described a mass flow measuring system for measuring the flow rate of a fluid in a sensing tube over a wide ambient temperature range and with low sensitivity to attitude change. The improvement is directed to the insulating material which is used with the system and the means for producing an isothermal plane around the system.