Pumping systems Propeller pumps

By changing the role of the piezoelecttic crystal from regulating drop formation to propelling drops, the need for high pressure ink-pumping systems, drop charging and deflection systems, and waste ink plumbing systems were eliminated. 

The heart, a four-chambered muscular pump has as its primary purpose the propelling of blood throughout the cardiovascular system. The left ventricle is the principal pumping chamber and is therefore the largest of the four chambers in terms of muscle mass. The efficiency of the heart as a pump can be assessed by measuring cardiac output, left ventricular pressure, and the amount of work requHed to accomplish any requHed amount of pumping. 

Axial-Flow (Propeller) Pumps (Fig. 10-44) These pumps are essentiahy very-high-capacity low-head units. Normally they are designed for flows in excess of 450 mVh (2000 gal/min) against heads of 15 m (50 ft) or less. They are used to great advantage in closed-loop circulation systems in which the pump casing becomes merely an elbow in the line. A common installation is for calandria circulation. A charac teristic cui ve of an axial-flow pump is given in Fig. 10-45. 

Cavitation erosion With increasing ship speeds, the development of high-speed hydraulic equipment, and the variety of modem fluid-flow applications to which metal materials are being subjected, the problem of cavitation erosion becomes ever more important. Erosion may occur in either internal-flow systems, such as piping, pumps, and turbines, or in external ones like ships propellers (36). 

Use well-designed, specialized polymer dissolution systems wherever possible (such as those from the U.S. Filter, Inc. subsidiary, Strandco ), especially for emulsion polymers, rather than simple dissolving tanks and mixers with propeller-type impellers. This prevents undissolved lumps of polymer (fish-eyes) and the breakdown of polymer chains. Always install a strainer to prevent possible pump clogging. 

In a solid-propellant rocket motor, the propellant is contained within the wall of the combustion chamber, as shown in Fig. 1. This contrasts with liquid systems, where both the fuel and oxidizing components are stored in tanks external to the combustion chamber and are pumped or pressure-fed to the combustor. In hybrid systems, one component, usually the fuel, is contained in the combustion chamber, while the other component is fed to the chamber from a separate storage tank, as in liquid systems. The solid-propellant motor also has an ignition system located at one end to initiate operation of the rocket. The supersonic nozzle affects the conversion of... 

Whenever corrosion resistance results from the formation of layers of insoluble corrosion products on the metallic surface, the effect of high velocity may be to prevent their normal formation, to remove them after they have been formed, and/or to preclude their reformation. All metals that are protected by a film are sensitive to what is referred to as its critical velocity i.e., the velocity at which those conditions occur is referred to as the critical velocity of that chemistry/temperature/veloc-ity environmental corrosion mechanism. When the critical velocity of that specific system is exceeded, that effect allows corrosion to proceed unhindered. This occurs frequently in small-diameter tubes or pipes through which corrosive liquids may be circulated at high velocities (e.g., condenser and evaporator tubes), in the vicinity of bends in pipelines, and on propellers, agitators, and centrifugal pumps. Similar effects are associated with cavitation and mechanical erosion. 

The human heart begins pumping approximately 3 weeks after conception and must continue this activity without interruption all day, every day, for an entire lifetime. In a typical individual, this means the heart pumps over 100,000 times per day and propels about 2000 gallons of blood through almost 65,000 miles of blood vessels. This function of the heart will be discussed here as well as in the following chapter on cardiac output. The function of the blood vessels will be considered in the chapter on the circulatory system. 

Lymphatic capillaries join together to form larger lymphatic vessels that have valves within them to ensure the one-way flow of lymph. The lymph is moved along by two mechanisms. Automatic, rhythmic waves of contraction of the smooth muscle in the walls of these vessels are the primary mechanism by which lymph is propelled through the system. Second, the contraction of skeletal muscles causes compression of lymphatic vessels. As in the veins, this pumping action of the surrounding skeletal muscles contributes to movement of the lymph. Ultimately, the lymph is returned to the blood when it empties into the subclavian and jugular veins near the heart. 

Figure 6 Schematic diagrams of atypical high-pressure SF-CL systems based on special mixing modes (a) system based on conventional propelling and stopping syringe and (b) system based on liquid chromatographic (LC) pumps and stopping the flow before the mixer (M). V, six-ports valve. (Adapted from Refs. 33 and 34.)...

It is usually understood that a rocket motor is that part of the propulsion system in which the propellants are transformed into the exhaust jet, while a rocket engine is the entire system, ie, the rocket motor, the proplnt containers, pumps, etc. In conventional solid proplnt rockets, the motor and the engine happen to be the same piece of apparatus, but this is not so in liq proplnt rockets... 

Neutralization of the sulfonic acid and building up with sodium sulfate and tetrasodium pyrophosphate (TSPP) is accomplished in two batch reactors (5 hr cycle) operated alternately. The sodium sulfate is pumped in solution with its transfer pump from the sodium sulfate system (which can be represented by a block). The TSPP is supplied as a solid and is fed by means of a Rcdler conveyor which discharges into a weigh hopper running on a track above the two reactors. Each reactor is agitated with a propeller and a turbine blade in a single shaft. 

The key part of the system is the multiport valve, which interconnects the different parts and solutions used by the system. The common port is connected to a reversible pump with the retention coil placed in between. The pump is connected to the carrier solution reservoir. The common port can access any of the other ports, which lead to sample, standard solutions or reagents, mixing chamber and sensor array, by electrical rotation of the valve. Since the system is bidirectional, volumes can not only be propelled directly to the detector, but also be injected into the retention coil, therefore merging accurate aliquots of different solutions. In order to assure proper mixing of the solutions not only via diffusion... 

A propelling system This is a peristaltic pump used to propel fluids along continuous segmented systems—flexible plastic tubing is squeezed by a series of rollers, which starts the flow of the enclosed liquids as a result. These systems can work with several streams, and the flow rate is determined by the internal diameter of the tube and the pump rotation speed. 

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