Venturi inlet

Figure 5. Venturi inlet steam temperature-time profile. Commercial...

Run 907-1A was a month-long adipic acid-enhanced limestone run with forced oxidation, designed to demonstrate operational reliability with respect to scaling and plugging and to demonstrate the removal enhancement capability of the adipic acid additive. This run was controlled at a nominal limestone stoichiometry of 1.7 (compared to 1.4 for the base case run, Run 901-1A) and 1,500 ppm adipic acid in the spray tower. Venturi inlet pH was controlled at a minimum of 4.5 by the occasional addition of limestone to the venturi loop. 

Premix duct based on a lean premixed prevaporised (LPP) concept with a venturi configuration, which has been optimized in order to obtain a good velocity profile at the inlet to the catalytic section. Fuel is injected upstream of the venturi minimum section with injectors angled relative to the airflow. Mixing is achieved with an inlet radial/axial turbulence generator in the venturi inlet. 

Dupeyrat, G., Rowe, B.R., Fahey, D.W., Albritton, D.L. (1982) Diagnostic stndies of venturi inlets for flow reactors. International Journal of Mass Spectrometry and Ion Processes, 44,1-18. 

Fig. 83 A schematic diagram of a PTR-MS instrument showing the hollow cathode (HC) ion source, the source drift region (SD), the Venturi inlet (VI) and the drift tube...

The vapor bulb was streamlined to minimize turbulence at the Venturi inlet the volume of the bulb was kept small (1.3 cm ) for good time response and, again, to minimize turbulence. About 100 mg of hydrous ferric oxide catalyst were contained within the bulb to insure essentially complete para conversion of the hydrogen in the bulb. 

The system of differential thermocouples, 59 in all, is composed of one 36-gauge gold—cobalt lead and an appropriate number of 36-gauge copper leads, each of which passes through a rubber compression-type seal at the top of the tank. A reference junction for the entire series of thermocouples is attached to a small parahydrogen-filled vapor bulb located below the Venturi inlet reference temperature information, therefore, is derived from bulb pressure data... 

Figure 8.6 Schematic diagrams for the ICP/SIFT (top) and Elan 6100DRC (bottom) instruments. In the ICP/SIFT instrument ions are produced in a plasma source and sampled by a standard atmosphere-vacuum interface (see text). The ion of interest is mass-selected in Q1, after which it is passed to the flow tube via a Venturi inlet. The flow tube is kept at a constant pressure of 0.35 Torr. Thermalized ions react with a neutral admitted at the reagent inlet as they flow downstream (to the right). Product ions are mass analyzed by Q2. In the Elan 6100DRC, ions are produced and sampled as above but are then reacted in a bandpass quadrupole reaction cell (DRC). Unreacted ions and product ions are detected by the mass analyzer quadrupole.

Figure 3.10 Schematic cross section of an ion source and drift tube from the laboratory of one of the authors. Here the drift tube is constructed from a single block of Teflon and the metal electrodes are located in slots on the outside of the drift tube. A Venturi inlet was employed to introduce the analyte gas into the drift tube. HC refers to the hollow cathode discharge region...

Flow Nozzles. A flow nozzle is a constriction having an eUiptical or nearly eUiptical inlet section that blends into a cylindrical throat section as shown in Figure 8. Nozzle pressure differential is normally measured between taps located 1 pipe diameter upstream and 0.5 pipe diameters downstream of the nozzle inlet face. A nozzle has the approximate discharge coefficient of an equivalent venturi and the pressure drop of an equivalent orifice plate although venturi nozzles, which add a diffuser cone to proprietary nozzle shapes, are available to provide better pressure recovery. 

Example 3 Venturi Flowmeter An incompressible fluid flows through the venturi flowmeter in Fig. 6-7. An equation is needed to relate the flow rate Q to the pressure drop measured by the manometer. This problem can he solved using the mechanical energy balance. In a well-made venturi, viscous losses are neghgihle, the pressure drop is entirely the result of acceleration into the throat, and the flow rate predicted neglecting losses is quite accurate. The inlet area is A and the throat area is a. 

Flow Nozzles A simple form of flow nozzle is shown in Fig. 10-17. It consists essentially of a short cylinder with a flared approach section. The approach cross section is preferably elliptical in shape but may be conical. Recommended contours for long-radius flow nozzles are given in ASME PTC, op. cit., p. 13. In general, the length of the straight portion of the throat is about one-h f throat diameter, the upstream pressure tap is located about one pipe diameter from the nozzle inlet face, and the downstream pressure tap about one-half pipe diameter from the inlet face. For subsonic flow, the pressures at points 2 and 3 will be practically identical. If a conical inlet is preferred, the inlet and throat geometry specified for a Herschel-type venturi meter can be used, omitting the expansion section. 

See Benedict, loc. cit., for a general equation for pressure loss for nozzles installed in pipes or with plenum inlets. Nozzles show higher loss than venturis. Permanent pressure loss for laminar flow depends on the Reynolds number in addition to p. For details, see Alvi, Sri-dharan, and Lakshamana Rao, J. Fluids Eng., 100, 299-307 (1978). 

FIG. 17-60 Reverse-pulse fahric filter (a) filter cylinders (h) wire retainers (c) collars (d) tube sheet (e) venturi nozzle (f) nozzle or orifice (g) solenoid valve (h) timer (/) air manifold (k) collector housing (/) inlet (m) hopper (n) airlock (o) iipperplenum, (Mikropul Division, US. Filter Coip.)... 

Preconditioning for Particulates Heavy particulate loading of the inlet gas with dust, grease, oils, or other aerosols can be very dam-aging to the pore structure of the filter bed, resulting in an eventual pressure-drop increase. Oils and heavy metals that are deposited on the filter bed can be poisonous to the microorganisms that live within the biofilm. Particulate APC equipment such as fabric filters and venturi scrubbers are generally adequate for this level of particulate removal. 

When the pollutant loading is exeeptionally high or consists of relatively large particles (> 2 /tm), venturi scrubbers or spray chambers may be used to reduce the load on the ESP. Much larger particles (> 10 /tm) are controlled with mechanical collectors such as cyclones. Gas conditioning equipment to reduce both inlet concentration and gas temperature is occasionally used as part of the original design of wet ESPs (AWMA, 1992 Flynn, 1999). 

Saug-luft, /. vacuum, suction inlet air. -luft-anlage, /. vacuum equipment or plant, -liifter, m. exhauster, -luftkessel, m. vacuum vessel, -maschine, /. exhauster aspirator, -messer, m. vacuometer. -nkpfchen, n. suction cup. -papier, n. absorbent paper, -pipette, /. suction pipet(te). -pumpe, /. suction pump, -raum, m. suction chamber, -rohr, n., -rohre,/. suction tube or pipe, sucking pip siphon Venturi tube, -rdhrehen,... 

RINLCT INLCT cone INLCT RINS iNLer seLL INLET PLARE INLeT NOZZLE VENTURI... 

---