Pumps motive

Once the chemical is measured (metered) to prepare the proper strength solution, a motive pump can be used to move it to the point of application. Motive pumps may be metering pumps but not always. Simple centrifugal pumps (or other types) can be used to provide satisfactory pressure and flow to deliver the solution to the application point. It is necessary to use care when selecting these pumps to ensure the materials are compatible with the diluted chemical being transported. 

The collection of particles larger than 1—2 p.m in Hquid ejector venturis has been discussed (285). High pressure water induces the flow of gas, but power costs for Hquid pumping can be high because motive efficiency of jet ejectors is usually less than 10%. Improvements (286) to Hquid injectors allow capture of submicrometer particles by using a superheated hot (200°C) water jet at pressures of 6,900—27,600 kPa (1000—4000 psi) which flashes as it issues from the nozzle. For 99% coUection, hot water rate varies from 0.4 kg/1000 m for 1-p.m particles to 0.6 kg/1000 m for 0.3-p.m particles. 

Jet Pumps. A jet pump is a clever way of using a high pressure motive fluid and a venturi to aspire a low pressure fluid to an intermediate pressure level. 

Condensa.te Recovery Pumps. The condensate recovery pump is a unique design that utilizes a motive steam or an air supply to move condensate. It can be appHed to capacities up to 23,000 kg/h (50,000 lb /h), providing valuable recovery of condensate or other Hquids, which otherwise would be wasted. 

Transfer of Momentum Deceleration of one fluid (motivating fluid) in order to transfer its momentum to a second fluid (pumped fluid) is a principle commonly used in the handhng of corrosive materials, in pumping from inaccessible depths, or for evacuation. Jets and eductors are in this categoiy. 

Motivation Unit tests require a substantial investment in time and resources to complete successfully. This is the case whether the test is a straightforward analysis of pump performance or a complex analysis of an integrated reactor and separation train. The uncertainties in the measurements, the likelihood that different underlying problems lead to the same symptoms, and the multiple interpretations of unit performance are barriers against accurate understanding of the unit operation. The goal of any unit test should be to maximize the success (i.e., to describe accurately unit performance) while minimizing the resources necessary to arrive at the description and the subsequent recommendations. The number of measurements and the number of trials should be selected so that they are minimized. 

The ejector is widely used as a vacuum pump, where it is staged when required to achieve deeper vacuum levels. If the motive fluid pressure is sufficiently high, the ejector can compress gas to a slightly positive pressure. Ejectors are used both as subsonic and supersonic devices. The design must incorporate the appropriate nozzle and diffuser compatible with the gas velocity. The ejector is one of the ( to liquid carryover in the suction gas. 

The above expression ean be solved by a trial and error ealeulation, whereby the following key assumptions are applied (1) the flow is turbulent, i.e., Re s 2,100, and (2) motive power is supplied by a prime mover sueh as a pump or a eompressor. To make this expression easier to use, the terms are rearranged in the following maimer ... 

If still greater force is required, a positive pressure in excess of atmospheric can be applied to the suspension by a pump. This motive force may be in the form of compressed air introduced in a montejus, or the suspension may be directly forced through a pump acting against the filter medium (as in the case of a filter press), or centrifugal force may be used to drive the suspension through a filter medium as is done in screen centrifuges. 

Photosynthetic electron transport, which pumps into the thylakoid lumen, can occur in two modes, both of which lead to the establishment of a transmembrane proton-motive force. Thus, both modes are coupled to ATP synthesis and are considered alternative mechanisms of photophosphorylation even though they are distinguished by differences in their electron transfer pathways. The two modes are cyclic and noncyclic photophosphorylation. 

Pumping and Lifting Liquids Using steam as the motive fluid... 

Steam jet syphons Steam jet slurry heater Single-stage vacuum pumps Using air as the motive fluid Air jet exhausters Using liquid as the motive fluid Water jet eductors... 

Convection is classified according to the motivating flow. When the flow takes place because of density variations caused by temperature gradients, the motion is called natural convection. When it is caused by an external agency such as a pump or a fan the process is called forced convection. 

Although not widely used for gears, oil-mist lubrication is nevertheless worth mentioning here. It is a total loss technique in which the oil is supplied in the form of fine droplets carried by compressed air. Two virtues are that the lubricant can be carried long distances through pipes without severe frictional losses, and that no oil pumps are needed since the motive power is provided by factory compressed-air lines. However, unless such systems are totally enclosed, the exhaust can create a build-up of oil-mist in the atmosphere. In order to maintain good standards of industrial hygiene, it is recommended that... 

Currently, five different molecular classes of mdr efflux pumps are known [5], While pumps of the the ATP-binding cassette (ABC) transporter superfamily are driven by ATP hydrolysis, the other four superfamilies called resistance-nodulation-division (RND), major facilitator superfamily (MFS), multidrug and toxic compound extrusion (MATE), and small multidrag resistance transporter (SMR) are driven by the proton-motive force across the cytoplasmic membrane. Usually a single pump protein is located within the cytoplasmic membrane. However, the RND-type pumps which are restricted to Gram-negative bacteria consist of two additional components, a periplasmic membrane fusion protein (MFP) which connects the efflux pump to an outer... 

The piston pump can be directly driven by steam, in which case the piston rod is common to both the pump and the steam engine. Alternatively, an electric motor or an internal combustion engine may supply the motive power through a crankshaft because the load is very uneven, a heavy flywheel should then be fitted and a regulator in the steam supply may often provide a convenient form of speed control. 

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