Metering Pumps liquid pump

Some polymer systems use liquid polymer. Then the polymer powder feeder would be replaced by a very small metering pump. This pump would need calibration for monitoring, as a flow meter is impracticable here. 

Liquid Eeeders. Liquid feeders employ positive-displacement metering pumps for adding aqueous solutions of sodium or calcium hypochlorite. The feed solutions are typically stored in polyethylene tanks of various capacities up to about 0.19 m (50 gal). 

Liquid-Solid Mixtures Liptak [Chem. Eng., 74(4), 151-158 (1967)] discusses a variety of techniques that can be used for the measurement of sohds-in-liquid suspensions or slurries. These include metering pumps, weigh tanks, magnetic flowmeter, ultrasonic flowmeter, gyroscope flowmeter, etc. 

Overfill drum due Calibrate weighing devices and maintain equip-to operator error ment in good working order or valve failure,. metering pumps can lead to opera- tor exposure, slip- fill operation with weighing device pery floors, spread of flammable liquids. CCPS G-3 CCPS G-15 CCPS G-22 CCPS G-29... 

At the time of the solvent methanol experiments a metering pump was used. In some experiments the pulsating action of the pump can be disturbing, so a high-pressure syringe-type pump can be used. Since mass flow controllers are available now, the combination of a gas-pressurized feed tank on an electronic scale for liquid level indication and a mass flow controller seems to be a good choice. Both the feed tank and separator can be heated or cooled. In the case of the solvent methanol experiments. 

Maximum operating pressure, 33 Diaphragm metering pump, 214 DIERS, final reports, 523 Discharge coefficients, liquid flow, Q, chart, 118... 

Liquid polyhydric alcohol from supply tank 11 via valved line 12 is fed through metering pump 13 in predetermined proportions via line 14 to tubular reactor 15. Simultaneously, ni-... 

Mehta, R. R. 517,565 Melting of particles 410 MliRKbL, F. 766, 786 Metering pumps 320 Meters, liquid 266 Metre 3, 4... 

I. Reactor 3. pH meter 5. A-V meter 7. Thermocouple 9. Liquid metering pump... 

Liquid flowing into the chromium treatment module [T-21] is monitored by a pH instrument that controls a feed pump to add the required amount of sulfuric acid from a storage tank. The sulfuric acid is needed to lower the pH to 2.0 to 2.5 for the desired reduction reaction to occur. An ORP instrument controls the injection rate of sodium metabisulfite solution from a metering pump to reduce hexavalent chromium (Cr6+) to the trivalent state (Cr3+). 

Another efficiency which is important for positive displacement pumps is the volumetric efficiency. This is the delivered capacity per cycle as a percentage of the true displacement per cycle. If no slip occurs, the volumetric efficiency of the pump is 100 per cent. For zero pressure difference across the pump, there is no slip and the delivered capacity is the true displacement. The volumetric efficiency of a pump is reduced by the presence of entrained air or gas in the pumped liquid. It is important to know the volumetric efficiency of a positive displacement pump when it is to be used for metering. 

Methanol or dimethyl ether feeds were fed from an ISCO positive-displacement pump. Liquid products were collected in a room-temperature trap and gaseous products were analyzed by on-line gas chromatography and volumes measured by a wet-test meter. The catalyst could be regenerated in-situ by switching to a nitrogen/air mixture. 

The mixed acid (72), brought to the nitration house by means of a centrifugal pump, is fed into the nitrator via a metering pump. The flow of the two reacting liquids is maintained in the correct proportion by means of speed controller. 

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. 

As far as maintenance is concerned, the pump motors must be lubricated periodically, and the pump must not be operated without liquid in it. The inlet piping must be designed to prevent cavitation. A metering pump should be calibrated not only before it is first used, but also periodically during its operation. The calibration should duplicate fluid properties, suction and discharge pressures, and inlet and outlet piping configuration. 

The feed pump was a positive-displacement, piston-type metering pump. All liquid transfer lines in the system were traced with electric resistance heaters which allowed us to process heavy SRC solutions. 

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