Siphon

3 Key excerpts on "Siphon"

• 

  eBook - ePub

  Pumps and Hydraulics, Part 1 (of 2)

  • N. (Nehemiah) Hawkins(Author)
  • 2018(Publication Date)
  • Perlego

    (Publisher)

  THE SYPHON.

  The Syphon is a bent pipe or tube with legs of unequal length, used for drawing liquid out of a vessel by causing it to rise in the tube over the rim or top. For this purpose the shorter leg is inserted in the liquid, and the air is exhausted by being drawn through the longer leg. The liquid then rises by the pressure of the atmosphere and fills the tube and the flow begins from the lower end.

  The general method of use is to fill the tube in the first place with the liquid, and then, stopping the mouth of the longer leg, to insert the shorter leg in the vessel; upon removal of the stop, the liquid will immediately begin to run. The flow depends upon the difference in vertical height of the two columns of the liquids, measured respectively from the bend of the tube, to the level of the water in the vessel and to the open end of the tube. The flow ceases as soon as, by the lowering of the level in the vessel, these columns become of equal height or when this level descends to the end of the shorter leg.

  The atmospheric pressure is essential to the support of the column of liquid from the vessel up to the top of the bend of the tube, and this height is consequently limited; at sea height the maximum height is a little less than 34 feet for water, but this varies according to the density of the fluid .

  Figs 54 55 56 57 58 59

  Syphons are necessary in numerous manipulations of the laboratory , and modern researches in chemistry have given rise to several beautiful devices for charging them, and also for interrupting and renewing their action. When corrosive liquids or those of high temperatures are to be transferred by syphons, it is often inconvenient, and sometimes dangerous to put them in operation by the lungs. Moreover cocks and valves of metal are acted on by acids, and in some cases would affect or destroy the properties of the fluids themselves.

  Fig. 54 shows how hot or corrosive liquids may be drawn off from a wide mouthed bottle or jar. The short leg of a syphon is inserted through the cork, and also a small tube, through which the operator blows, and by the pressure of his breath forces the liquid through the syphon.

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  eBook - ePub

  Hydraulics of Spillways and Energy Dissipators

  • Rajnikant M. Khatsuria(Author)
  • 2004(Publication Date)
  • CRC Press

    (Publisher)

  The two most commonly used are the step or deflector (Fig. 3) and the baby Siphon (Fig. 4). Figure 3 Siphon with step. Figure 4 Siphon with a baby Siphon. In a volute Siphon, (Ganesh Iyer 1950) shown in Figure 2, the lip of the funnel is kept at FRL and a number of volutes (like the blades of pumps or turbines) are placed on the funnel to induce a spiral motion of water passing along them. When the water rises above FRL, it spills, over the circumference of the lip of the funnel and flows along the volutes with a spiral motion, forming a vortex in the vertical pipe. This induces a strong suction pool creating a powerful vacuum, which sets the Siphon in action. To stop the Siphonic action, air is let in through small pipes taking off from the crown of the dome with their inlet opened at FRL. 7.4 HYDRAULIC DESIGN CONSIDERATIONS The following characteristics are relevant in the hydraulic design of Siphon spillways: Discharging capacity Priming depth Regulating flow Stabilizing function Effect of waves in the reservoir Cavitation Vibration 7.5 DISCHARGING CAPACITY The flow in the throat section of a saddle Siphon can be idealised as a free vortex, so that R = V 1 R 1 = V 2 R 2 = constant (1) where V = Velocity of flow R = Radius Subscript irefers to quantities at the crest and subscript 2 refers to the crown of the Siphon. V = V 1 R 1 R (2) Referring to Figure 1, discharge through an elemental area dA formed by a strip dR and throat width b. is Q A = V 1 R 1 R d A = V 1 R 1 R b d R (2a) and hence Q = ∫ R 1 R 2 V 1 R 1 R b d R = V 1 R 1 b ∫ R 1 R 2 d R R = V 1 R 1 b [ ln R 2 R 1 ] (3) Since, the maximum value of V 1 is 12. m/s, Q max = 1 2 R 1 b [ ln R 2 R 1 ] (4) and the average velocity will be V a = Q A = 1 2 R 1 b (R 2 - R 1) b [ ln R 2 R 1 ] = 1 2 R 1 (R 2 - R 1) [ ln R 2 R 1 ] (5) This velocity should be the same at all sections along the Siphon barrel unless there is expansion or contraction of the section

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  eBook - ePub

  Functionality, Advancements and Industrial Applications of Heat Pipes

  • Bahman Zohuri(Author)
  • 2020(Publication Date)
  • Academic Press

    (Publisher)

  Chapter 7

  Thermodynamic analysis of thermosyphon

  Abstract

  Thermosyphons are devices with high thermal conductivity that can transfer high quantities of heat. In its most simple form, a thermosyphon is a hollow evacuated metal pipe, charged by a pre-determined amount of an appropriate working fluid. It can be divided into three main sections: evaporator, where the heat is delivered to the device, an adiabatic section (which can or cannot exist) and a condenser, where the heat is released. The working fluid located in the evaporator evaporates and, by means of pressure gradients, go toward the condenser region, where it condenses, returning to the evaporator by means of gravity. Complicated mathematical expressions and numerical schemes are helpful but sometimes may mask the real physics from a design engineer's point of view. Usually it is not desirable or necessary to get into such detail for most applications. Therefore, a simple and understandable engineering method for analysis of thermosyphon performance becomes attractive in practice. This chapter provides a different view into the physics behind thermosyphon performance, based on thermodynamics.

  Keywords

  Thermodynamics; Thermosyphon; High temperature thermosyphons; Device manufacturing

  1. 7.1 Introduction 
  2. 7.2 General model (vertical thermosyphon) and flooding 
  3. 7.3 Two-phase thermosyphon thermodynamic analysis with spiral heat exchanger 
  4. 7.4 Summary 
  5. References 

  7.1. Introduction

  With the world energy crisis, where petroleum become more expensive and scarcer, where hydroelectric resources are exhausting and where new technologies that enable the use of Solar and Eolic (Wind) energies are not economically viable, the importance of procedures to improve the energetic efficiency of industrial processes is growing, leading to the development of new solutions. High temperature streams (above 600

   

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