Pressure glass tubes

The pressure glass tube was to be filled with a 5 ml MEK/4.75 water mixture, since according to the International Critical Tables, this mixture has an LCST of about —16°C. About 0.4 ml of vinyl acetate (VA) was to be incorporated into the mixture. The actual sequence used was the addition of 5 ml MEK into the pressurized glass tube followed by the 0.4 ml VA, and then finally injecting in the 4.75 ml water which resulted in a cloudy mixture. Then, the glass tube was sealed using the Teflon ... 

Fig. 2.2.6 Pressure (10 atm maximum pressure) glass tube reactor used to obtain catastrophic release of reaction exotherm from self-polymerization of vinyl acetate in MEK/water mixtures...

The metal clamp holding the pressurized glass tube was damaged. The plastic on the clamp was charred completely. The metal part was deformed quite severely due to melting, and phase separated the copper from the alloy. 

Fig. 2.2.7 Remnants of the glass tube reactor FRRPP experiment showing deformed metal clamp showing the reddish phase separated inner part (center), carbonized plastic samples in bottles, partially charred Teflon cap (left center), syringe remains (lower left side), and pressurized glass tube container with carbonized material (right side)...

Toward the above goal, in a large number of preliminary experiments we initially attempted the VDF polymerization at moderate temperatures (25-60 C) in low pressure glass tubes via conventional LRP methods (e.g., Cu-ATRP [53], nittoxides, RAFT, Cp2TiCl [54,55]). However, all polymerizations were unsuccessful, most likely due to the inability of the particular systems to generate radicals reactive enough to add to VDF, or to reactivate the PVDF-Y chain ends at or around rt, or due to PVDF vs. catalyst solvent incompatibility [54], Indeed, while, for example. 

Variable-Area Flow Meters. In variable-head flow meters, the pressure differential varies with flow rate across a constant restriction. In variable-area meters, the differential is maintained constant and the restriction area allowed to change in proportion to the flow rate. A variable-area meter is thus essentially a form of variable orifice. In its most common form, a variable-area meter consists of a tapered tube mounted vertically and containing a float that is free to move in the tube. When flow is introduced into the small diameter bottom end, the float rises to a point of dynamic equiHbrium at which the pressure differential across the float balances the weight of the float less its buoyancy. The shape and weight of the float, the relative diameters of tube and float, and the variation of the tube diameter with elevation all determine the performance characteristics of the meter for a specific set of fluid conditions. A ball float in a conical constant-taper glass tube is the most common design it is widely used in the measurement of low flow rates at essentially constant viscosity. The flow rate is normally deterrnined visually by float position relative to an etched scale on the side of the tube. Such a meter is simple and inexpensive but, with care in manufacture and caHbration, can provide rea dings accurate to within several percent of full-scale flow for either Hquid or gas. 

H is placed at the highest available level (Note 5) and connected with the tubes 7, 7, and K in such a manner as to secure a pressure of liquid sufficient to more than balance the steam pressure (Note 6). E and F are specially constructed condensers of unusual length (160 cm. and 85 cm., respectively) and bore (40 mm.) made from large glass tubing and rubber stoppers (Note 7). I he top of condenser E is connected to a good draft chamber. 

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