Flow indicators

Fig. 11. Flow control system (11). FIC = flow indicator controller.

Density Gauges These are used to measure the density or suspended solids content of the feed and underflow streams. Gamma radiation devices are the most commonly used for automatic control, but ultrasonic devices are effective in the lower range of slurry density. Marcy pulp density scales are an effective manually operated device. A solids mass flow indication is usually obtained by combining a density gauge output with the output from a flowmeter. 

The shaft seal (see subsection Shaft Seals ) generally is a close-clearance labyrinth-type seal. It is desirable that there be available a suitable pressurized buffer gas for injection into the intermediate point in the seal, such gas to be available at an absolute pressure well above the highest shaft pressure to be sealed. Then the seal-gas system may consist of only a filter, a flow-indicating device, and a throttle... 

Internal surfaces were moderately tuberculated (Fig. 3.14). Extremely thick, hard magnetite shells capped large internal cavities (Fig. 3.9). Pipe cross-sectional area was reduced by at least 30% in some places. Tubercles were aligned with flow, indicating that growth occurred during service. No failure occurred, and deepest metal loss was only 0.093 in. (0.033 cm) from the nominal pipe wall thickness of 0.225 in. (0.572 cm). 

Vent system Test system back pressure before use inoperable, Flow indication or pressure drop indication or clogged. ACGIH 1986 CCPS G-3 CCPS G-22 CCPS G-23 CCPS G-29... 

Flow Low mass flow indicated. Mass flow error. Transmitter zero shift. Measurement is high. Measurement error. Liquid droplets in gas. Static pressure change in gas. Free water in fluid. Pulsation in flow. Non-standard pipe runs. Install demister upstream heat gas upstream of sensor. Add pressure recording pen. Mount transmitter above taps. Add process pulsation damper. Estimate limits of error. 

A flow indicator on each pass with a low flow alarm. 

The explosion occurred because key instruments were not kept in working order. The flow indicator and low flow alarm (FIA) were out of order. They often were, and the operators had found that the plant could be operated without them. If there is no flow, they thought, J2 will have stopped, and this will stop Jl. 

More effort might have been made to keep the flow indicator alarm in working order. 

Flow indicator ditTerenlial type locally mounted... 

Figure 5.10.3, Vessels—level control on outlet. Legend FIC, flow indicator controller LG, level gauge LIC, level indicator controller LAWL, level alarm for water level, M, motor.

Abnormal Formation Pressure Detection from Kicks. The kicks, or flow of formation fluids into the borehole, are the ultimate indication that the well has encountered an overpressured zone. Kick detection during drilling usually is achieved by use of a pit-volume indicator and/or a flow indicator. The usual pit-volume alert is 10 barrels drilling fluid volume increase. A differential mud flow indicator can also be used to detect kicks more quickly. 

Rail tank cars have bottom outlets terminating in a quick-acting coupling, and are designed for pump off-loading only. A flow indicator should be inserted between the terminal outlet and the fill line. Flexible connections for steam and oil lines should be provided for the maximum number of cars that will be discharged simultaneously. 

If the unit pressure balance indicates that either the pressure gain in the standpipes is inadequate or the delta P across the slide valves is erratic, standpipe aeration and instrumentation should be examined. Redesigning the aeration systems or replacing the standpipes can gain valuable pressure drop. Proper instrumentation can include independent aeration flow to each tap, flow indicators/controllers on each, and differential pressure indicators between the taps. 

Figure 7.10 Schematic representation of the apparatus for measuring osmotic pressure. The flow of solvent through the semipermeable membrane is followed by observing the movement of the meniscus of the flow indicator. The osmotic pressure II is the pressure that must be applied to the solution to prevent the flow.

A satisfactory way to accomplish the introduction of chlorine with minimal loss of the gas is to seal the reaction flask with a two-holed stopper equipped with a gas-inlet tube reaching just above the surface of the reaction mixture and an exit tube connected to a U-tube filled with mineral oil which is used as a gas-flow indicator. Chlorine is then introduced from the cylinder through a safety trap at such a rate as to maintain a small positive pressure in the reaction flask. 

Failure of water pressure can spell disaster in laboratories where some operations, such as distillations, are dependent on water. Ideally, an audible alarm would indicate the lack of water pressure. Laboratory supply houses sell water flow indicators that can be placed in series with the water line to equipment. When water is flowing, a brightly colored ball in a clear tube will move or a small propeller will turn. These can be observed from a considerable distance by watchful laboratory personnel. 

ICH, intracranial hemorrhage TIMI, Thrombolysis in Myocardial Blood Flow (TIMI-3 blood flow indicates complete perfusion of the infracted artery). (Reprinted from Spinier SA, de Den us S. Acute Coronary Syndromes. In DiPiro JT, Talbert RL, Yee CC, et al, (eds.) Pharmacotherapy A Pathophysiologic Approach. 6th ed. New York McGraw-Hill 2005 303, with permission.)... 

Glycerol was to be ethoxylated at 115-125°C in a circulating reaction system with separate reactor, heat exchanger and catalyst units. The valve at the base of the reactor was still closed, but an inoperative flow indicator failed to indicate absence of circulation and a total of 3 tonnes of the oxide, plus glycerol, was charged to the reactor. Upon subsequent opening of the valve, the reaction mixture passed through the heater, now at 200° C, and a runaway reaction developed, the reactor burst and an explosion followed. 

The fact that lower risks occur in areas with high river flow indicates that the dilution factor once pharmaceuticals enter river waters can efficiently mitigate possible environmental hazards, while in areas where effluent wastewaters represent a big percentage of the receiving river water flow hazards to aquatic organisms may increase. 

None No flow - chlorine to chlorination loop No/low level in chlorine drum. Pressure reducing valve fails closed. No chlorine flow to tower basin. Low chlorine concentration in tower basin. Local pressure indication on chlorine injection line. Local flow indication on chlorine injection line (rotameter). 6 ... 

Pronk, A., Bobrowsky, P., Parkhill, M. 1989. An interpretation of late Quaternary glacial flow indicators in the Baie des Chaleurs region, northern New Brunswick. Geographie Physique et Quaternaire, 43, 179-90. 

Ice-flow indicators indicate the area was influenced primarily by the Laurentide Ice Sheet flowing to the WSW during the last Wisconsinan glaciation. Pebble lithology data show that surface till composition reflects local provenance of the underlying... 

A graph of the flows indicates no recycle streams exist, but the system cannot... 

To appreciate that charge flow indicates that one material is formed simultaneously at the expense of another. Since such materials are generally in solution, coulometry is a means of following concentration changes. 

The ratio of the rotational flows indicated that the diameter of the extruder is not a factor for the deviation shown in Fig. 7.16. That is, for this channel with a small H/Wthe simplified analysis produces less than a 10% error when compared to the exact numerical solution. Thus, the rotational flow rate can be calculated quite reliably using the simple generalized Newtonian method at these conditions. 

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