PRODUCTION
pressure apparatus. When air pressure is used in transferring liquids from carboys, the rubber stoppers or other closure d e vices must fit perfectly in the carboy neck. Some materials attack and harden rubber so that the periodic replacement of stoppers is required. Also there is t h e problem that carboy necks may vary in Carboy pump developed by research workers at Dow Chemical Co. offers size. Thi. use of air pressure to remove advantages over conventional methods of transferring corrosive liquids liquids from carboys necessitates the re PROBLEM common to chemical lab issed i n pumping a large variety of sol lease of air from the carboy at the end of oratories is the transfer of liquids from vents, acids, alkalies, and liquid organic the pumping operation. With materials glass carboys to reagent bottles, reactors, materials from rubber, glass, and metal such as ammonium hydroxide and hydro containers. As yet, no pump breakage has and other apparatus. A large variety of chloric acid, t h e discharged vapors are tippers, lifters, dippers, siphons, and been reported. highly corrosive and are discharged i n The apparatus has a pumping capacity pumps have been used for this purpose considerable volume, particularly if t h e ever since the advent of the carboy. o f approximately one gallon per minute carboy is almost empty. Then, too, it is Another approach to the problem has been when used with water. One stroke is re general practice to release the air pressure recommended by H. W. Moll of D o w quired to start the liquid flowing from the by slipping off the hose that connects the Chemical's organic research laboratory, pump, and six to seven strokes are needed air source and the glass tube leading into which has developed a glass pump for the per quart of liquid. T h e density of the the carboy. This presents a safety hazard safe and practical handling of corrosive liquid has no effect because the pump by increasing the possibility of glass tube liquids. T h e unit has been fabricated in operates on the positive displacement breakage. These various drawbacks are the company's glass blowing department principle. However, viscosity does in eliminated b y the use of the n e w carboy pump. under the direction of J. E . Ritzer. fluence the pumping rate, more viscous Carboys and bottles are generally used materials requiring a slower pump stroke Because the pump provides exceptional in transporting and storing liquid chemi rate. operating ease in the filling of containers cals that cannot be handled suitably in The operating principle of this pump directly from stock carboys, the laboratory any material other than glass. A satisfac offers advantages over t h e widely used personnel at Dow's organic research lab tory carboy-emptying mechanism should technique of applying pressure to a car oratory have done away with all of their be so designed that the liquid only comes boy b y way of a rubber bulb or other air old one-gallon laboratory storage bottles. in contact with glass or a material that is equally as resistant to corrosion. This con dition is satisfied by the glass carboy pump STOP FOR BOTTOM shown in the accompanying illustrations. Of STROKE PUT ONE • TO»» Of STROKE Liquid i s drawn into the pump on the upward stroke and discharged from the spout on the downward stroke. T h e clear ances, checks, and spout sizes have been designed t o minimize the possibility of { O O CAGE liquid being sprayed from the top by careless pumping. Drain ports have been located in such a manner that the unit is virtually dripless after pumping. Holdup is reduced to a minimum. The pump may b e constructed b y or dinary glass blowing techniques at a cost of about $ 2 5 a unit. The diameter of the Below. Assembled pump mounted on standard pump's Teflon piston is about 0.003 inch L - J O o GAGE GLASS Mo IS CUM RUBBER STOPPER| smaller than the inside diameter of the carboy is used principally WITH A TEFLON in filling 500-ml. a n d RING UNDERNEATH pump casing. The piston is slipped over MJ 100O-ml. reagent bottles -TEFLON RMG. SEE DETAIL the end of the plunger and is held in place f O O STO PYREX (SELECT FOR BORe by the rod cage which, in turn, is welded . το FIT UNIFORMITY) OVER { G A G E to the end of the plunger. T h e square -V» GLASS TUBE IS CHECK VALVES DETAIL OF PLUNGER TURN TO PISTON check valve housing design prevents side FIT FOR Γ Ο 0. STO. PVREX movement of the bail check and conse TUBE S-fOEEP GROOVES quent housing breakage. T h e spherical ALL AROUND TO GIVE 6 FLEXIBLE joint of the spout not only reduces break PISTON SECTIONS age but permits the interchange of various 0ETAIL OF TEFLON PLUNGER RING spout lengths. Apparatus of this type has been in con Drawing indicates structural tinuous use at the Dow Chemical Co. for details of glass carboy pump over a year and a half. It has been em capable of delivering approxi ployed in pumping 28% ammonium hy mately o n e gallon a minute droxide, 32'/, hydrochloric acid, 10 and 98% sulfuric acid, glacial acetic acid, dilute and 70*% nitric acid, and 10 and 30% sodium hydroxide. The pumps have at all tinu*s bren left in the carboys ex cept when il has been necessary to replace empty carbovs. As a result, the contam ination of pun* reagents has been prac tically eliminated. These nuits are finding increased appli cation In semi plant areas, where they are
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