Liquid Pump

When arriving at the performance of a pump, it is customary to calculate its power output, which is the product of (1) the total dynamic head and (2) the mass of liquid pumped in a given time. In SI units power is expressed in kilowatts horsepower is the conventional unit used in the United States. 

Centrifugal blowers or turbines usually cannot generate enough pressure difference to overcome the added resistance of the recycle pipes. In addition, some components may condense out in the cooler, especially with high-boiling materials or at high pressures. These must be recycled by a liquid pump through an evaporator. This in turn makes them approach a steady-state slowly. ... 

Calculate the outbreathing rate (for a combination of liquid pump-in and thermal breathing). 

HOPC uses a column packed with porous materials that have a pore diameter close to a dimension of the solvated polymer to separate. A concentrated solution of the polymer is injected into the solvent-imbibed column by a high-pressure liquid pump until the polymer is detected at the column outlet. The injection is then switched to the pure solvent, and the eluent is fractionated. A schematic of an HOPC system is illustrated in Fig. 23.1. A large volume injection of a concentrated solution makes HOPC different from conventional SEC. 

Simple single cylinder per cylinder of liquid pump uses more steam than compound. 

The slip of a pump is fraction or percent loss of capacity relative to theoretical. Slip is (1 — Cvoi), w here e oi is the volumetric efficiency. Volumetric efficiency is the actual liquid pumped (usually considered water) relative to that which should theoretically be pumped based on piston displacement. 

Materials of construction for this type of unit are usually modular cast iron rotors on steel shafts and cast iron casings or bodies. For special requirements in corrosive situations that cannot be remedied by changing the seal liquid, pumps can be furnished in Type 316 stainless steel or other alloys (expensive). 

Relief Yalve normally selected for liquid relief service such as hydraulic systems, fire and liquid pumps, marine services, liquefied gases, and other total liquid applications. The valve characteristically opens on overpressure to relieve its rated capacity, and then reseats. 

Sparks, C. R, andj. C. Wachel, Pulsations in Liquid Pumps and Piping Systems, Proceedings of the Fifth Turbomachinery Symposium, ASME. 

Pumps are a mechanical device that forces a fluid to move from one position to another. Usually a pump refers to the mechanical means to move incompressible (or nearly incompressible) fluid or liquid. Pumps are our earliest machine and are to this day one of our most numerous mechanical devices. 

Air or gas compressors are very similar in design and operation to liquid pumps discussed earlier. The air and gas compressor is a mover of compressed fluids the pumps are movers of basically incompressible fluids (i.e., liquids). 

In a compressor, like a liquid pump, the real volume flowrate is smaller than the displacement volume. This is due to several factors. These are ... 

Pressure gauges should always be fitted on the discharge side of liquid pumps, to check performance and give warning of a possible drop in flow resulting from dirty strainers. Manometer pressure gauges are required across air filters (see Chapter 2 7). 

It may be noted that energy will be required for compressing the air to the injection pressure which must exceed the upstream pressure in the pipeline. The conditions under which power-saving is achieved have been examined by DZIUB1NSKI(25j. who has shown that the relative efficiency of the liquid pump and the air compressor are critically important factors. 

Prassure Regulator Pressure Geuge Liquid pump J MFC... 

Absorbent yco2,f [-] Liquid pump Blower Vacuum ptimp Separation Total Separation and Liquefaction... 

Figure4.62 Experimental set-up for liquid/liquid experiments (a) reservoir for the substrate in n-heptane (b) water reservoir (c, d) high-pressure liquid pumps (e) HPLC injection valve with sample loop for catalyst injection (f) micro mixer ...

Figure 5.28 Schematic of the experimental set-up. Water/ethylene glycol/SDS reservoir (a) high-pressure liquid pumps (b) catalyst/ substrate HPLC injection valve with 200 pi sample loop (c) hydrogen supply, equipped with mass flow controller (d) micro mixer (e) heating jacket (f) tubular glass or quartz reactor (g) back-pressure regulator (h) [64],...

Following are some examples of passive safety systems to reduce the likelihood of explosions in storage units. The use of baffles in a high-pressure storage vessel can cool the tank wall above the liquid surface via liquid pumped around by vapor bubbles, extending the time for fire fighting. Fire resistant tank insulation is also effective in delaying a BLEVE. 

A typical emergency scrubber system consists of a scrubbing column (often filled with packing), recirculating liquid pumps, solvent cooler, and in some cases (where the entering effluent gas/vapor is at a low pressure) exhaust blowers (see Fig. 23-57). Redundant equipment and instrumentation is usually provided to ensure reliable scrubber operation at all times. 

The optimal plant operation can be determined by minimizing the total cost function, including steam costs, with respect to P (liquid pumping costs are negligible)... 

The suction head hs decreases and the discharge head hd increases with increasing liquid flow rate because of the increasing value of the friction head loss terms hfs and hfd. Thus the total head Ah which the pump is required to impart to the flowing liquid increases with the liquid pumping rate. 

Why is it that no ordinary liquid pump can be used as the pump in an HPLC system ... 

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