Laboratory metering pump

Peristaltic pumps [Fig. 7.12(h)] move the liquid by squeezing a tube behind it with a rotor. Primarily they are used as metering pumps at low capacities and pressures in corrosive and sanitary services when resistant flexible tubes such as those of teflon can be used, and in laboratories. 

The sand used as porous media was purchased from AGSCO Corp., Peterson, NJ. The transducer used for the measurements of pressure drop across the porous medium was supplied by (Validyne DP-15), Validyne Engineering Corporation, Northridge, CA. The recorder was obtained from (Heath/Schlumberger 225), Heath Company, Benton Harbor, MI. The water was pumped using Cheminert Metering Pump (Model EMP-2), Laboratory Data Control, Riviera Beach, FL. 

Plunger pumps have proved satisfactory for lai er plants with continuous operation. Metering pump heads of glass with PTFE bellows were already mentioned in chap. 5.1.3.1 (Fig. 143) [88]. Circulation pumps made of glass are put to a variety of uses for a capacity range up to 20 m /h and lifts up to 15 ra (Fig. 402). Metering pumps which may also be employed for the automatic mixing of various liquid streams (Fig. 403) in laboratory and pilot plant distillation [85] are manufactured by... 

Positive displacement meters—direct volumetric totalizers—are often used in laboratories for calibration. The principle is based on delivering a discrete volume of fluid in aliquots. In fact, water wheels and shadoofs could be considered as positive displacement meters. Pumps may also be considered as meters. 

Sand, used as a porous medium, was supplied by AGS CO Corp., Paterson, New Jersey, U.S.A., whereas the Berea sandstones were supplied by Cleveland Quarry, Cleveland, OH, U.S.A.. The size distribution for the sand used was 40-150 micron with average particle size of 95 micron. The sandstone cores were cast in Hysol Tooling Compound (Hi-Co Associates, Orlando, FL) inside PVC pipes. The sandpacks had permeabilities of about 2.5 darcy and porosities of 40%, whereas Berea sandstones had permeabilities of about 275 millidarcy cind porosities of 18%. The transducer used for the measurements of pressure across the porous medium was from Validyne Engineering Corp., Northrddge, CA, U.S.A.. The recorder was a Heath/Schlumberger Model 225, Heath Co., Benton Harbor, MI, U.S.A.. The water was pumped using a Cheminert metering pump Model EMP-2, Laboratory Data Control, Riviera Beach, FL, U.S.A.. 

The liquid chromatograph was laboratory assembled from commercially available components. The solvent delivery system consisted of a Metering Pumps Ltd. (London, Great Britain) liquid pump, type HM. Pulse damping was effected by the combination of a Bourdon type pressure gauge and a coiled length (25 m x 0.25 mm ID) of stainless steel capillary tubing. The electrochemical flow-cell was connected directly to the HPLC column. 

The disadvantages of this method ate the need for a torque meter, longer total length of the pumping unit, and greater susceptibiUty to misalignment and vibrations. This method is used only at a manufacturer s test faciUties or research laboratories. It is not used in the field. 

The main aspect of the job of the top floor person is to pump solvents or oil to various reactors and blenders. Instructions are issued on a job-card or by phone. The instructions are entered in a log book (which is kept by the top floor worker) and on a record card which has to be returned to the laboratory at the end of the shift. To prepare for pumping, protective clothing must be worn. After the required amoimt of solvent is set on the meter, the worker has to connect the meter and the pipeline with a hose and then open the valve on the pipeline (see Figure 7.10). Before starting the pump, the blender valve... 

Analyses were done on a Dionex Model 14 Ion Chromatograph (IC), equipped with a Waters WISP 7 autosampler, Linear recorder, and interfaced with a Hewlett-Packard 3354 Laboratory Automated System. The principal components of the IC, shown in Figure 2, are (A) eluent reservoir, (B) pump, (C) injection valve, (D) separator column, (E) suppressor column, (F) conductivity cell, and (G) conductance meter with a recorder (integrator). 

If the pressure at the gas-meter is too low to meet all the demands made on the supply it may be necessary to install a gas booster. This is simply a pump which raises the pressure above that provided by the gas works. The installation of a gas booster can seriously affect the gas supply to other users on the same main pipeline, and raise the pressure in adjoining laboratories to undesirable levels, it is therefore essential to consult the local gasworks engineer before such an expensive programme is undertaken. 

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