Flow bypassing

Main system relief valves are generally installed between the pump or pressure source and the first system isolation valve. The valve must be large enough to allow the full output of the hydraulic pump to be delivered back to the reservoir. This design feature, called a full-flow bypass, is essential for all hydraulic systems. The location... 

The emergency isolation devices should be arranged so that they can be fully function tested without affecting the process operation. This entails that a frill flow bypass should be installed at each emergency isolation valve. These bypass installations should be locked closed when not in service for functional testing the ESDV. 

Regardless of the arrangement of the HPRT train, a full-flow bypass valve with modulation capability must be installed. Common control of the modulating bypass valve and the HPRT inlet control valve is normally achieved by means of a spht-level arrangement (see Figure E-1). 

Ultrasound, particularly Doppler ultrasound, provides an indication of blood flow through the liver and whether that flow is reversed. This is another way of identifying whether first-pass metabolism is likely to be affected by collateral blood flow bypassing the liver. The scan may also show whether the liver is large and inflamed (hepatitis) or small and knobbly (cirrhosis). 

As shown in Fig. 3-9, flow over the packing surface between junctions is assumed to be laminar. At each junction a fraction, q, of the flow enters the perfectly mixed regions, corresponding to the static holdup region, while the remainder of the flow bypasses the mixing. The probability of an element of fluid being mixed at each junction is taken as q. Michell and Furzer66 derived the expression for the mean residence time for the liquid as... 

Recycle is feedback from downstream to upstream in the materials flow bypassing one or more units. Bypassing is feedforward bypassing one or more units. 

Using the conservation law for mass, express the process outlet flow in terms of the process inlet flow. Also express the flow bypassing the process in terms of the upstream and process inlet flows ... 

The following systems represent differing combinations of ideal plug-flow, mixing, dead space, flow recycle and flow bypass. 

Surround the gel with plastic film to prevent a short circuit (i.e., flow bypassing the gel producing uneven or no transfer) and place wet nitrocellulose membrane over the gel. Place one edge of the membrane just over the edge of the sample wells and carefully proceed downward. Do not move back once the membrane has touched the gel, particularly for blots with substantial amounts of target DNA. The membrane should not overhang the gel and no air bubbles should be trapped. 

Millipore Corporation, XX8140000) consisted of a membrane holder (Pellicon), a 4 gallon per minute rotary vane pump (Procon) and the membranes themselves. The filters were either 0.45 micron micro-porous (Durapore) or 100,000 NMWL ultrafiltration membranes. All tubing and connections were 1/2 inch. A manifold flow bypass was attached to the pump so fluid could be introduced into the filtration system without a sudden surge of pressure buildup (Bulletin AB822, Millipore Corporation). In all cases, 5 square feet of membrane were used. 

Run Vacuum (in. Hg) H2 Flow Bubbler (cc./min.) H2 Flow Bypass (cc./min.) Current Peak (ma.) Voltage Peak (volts)... 

In-line banks of high-finned tubes are not usually used in air-cooled heat-transfer equipment because the preferential flow path between the fin tips of adjacent tubes allows flow bypassing and reduces the apparent heat-transfer coefficient. This effect tends to disappear in the deeper tube banks used in convection sections of fired heaters. 

FIGURE 12.7-6 Adsorption using a closed-loop regeneration, Flow bypasses the healer during cooling. 

The fluid flow rate is uniformly distributed through the exchanger on each fluid side in each pass. No flow maldistribution, flow stratification, flow bypassing, or flow leakages occur in any stream. The flow condition is characterized by the bulk (or mean) velocity at any cross section. 

Targeting the alveolar region appears more feasible, since -20% of particles <3 pm that are inhaled at low flows bypass the nasopharynx and deposit in that region during nose breathing. 

An optimum H2/CO ratio in the methanol syngas can in all cases be ensured by a single-stage CO shift conversion unit. However, it will often be more cost-effective to convert only part of the clean gas to CO contents around 3-4 vol. %, while the remaining gas flow bypasses this section (and perhaps also the downstream CO2 scrubber). 

Shunt perfusion (i.e., flow bypassing exchange vessels)... 

The HPCS system can operate independently of normal auxiliary AC power, plant service air, or the emergency cooling water system. Operation of the system is automatically initiated from independent redundant signals indicating low reactor vessel water level or high pressure in the primary containment. The system also provides for remote-manual startup, operation, and shutdown. A testable check valve in the discharge line prevents backflow from the reactor pressure vessel when the reactor vessel pressure exceeds the HPCS system pressure such as may occur during initial activation of the system. A low flow bypass system is placed into operation until pump head exceeds the nuclear system pressure and permits flow into the reactor vessel. 

In bioanalytical practice the channel systems and tubular electrodes seem to be more useful. Such equipment can be easily attached to a reaction vessel (e.g., fermentation kettle) like a through-flow (bypass) tubing. A general computational approach [73] to the simulation of current-time transients was applied to double-potential step chronoam-perometry at a single-channel electrode. 

Operation of a pump with the discharge shut off forces all the frictional heat into a small volmne of liquid and can raise its temperature to dangerous levels. Note that provision of a minimmn-flow bypass around the pump may not prevent this situation if the fluid is returned directly to the suction of the pump. 

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