Piping traverse

Several recovery scenarios were considered for remediation. Initially, construction of a narrow, permeable trench parallel to the canal appeared to be an appropriate interception system. The construction technique considered was use of a specially designed deep trenching unit. This type of trench would have included a tile drain leading to a single two-pump recovery well. However, a review of the subsurface site plans and interviews with long-term employees determined that an unknown number of buried pipes traverse the area intended for the trench construction. Disruption of refining operations and safety considerations resulted in rejection of this option. 

Traversing for Mean Velocity Mean velocity in a duct can be obtained by dividing the cross section into a number of equal areas, finding the local velocity at a representative point in each, and averaging the results. In the case of rectangular passages, the cross section is usually divided into small squares or rectangles and the velocity is found at the center of each. In circular pipes, the cross section is divided into several equal annular areas as shown in Fig. 10-7. Read-... 

Once these traverse points have been determined, velocity measurements are made to determine gas flow. The stack-gas velocity is usually determined by means of a pitot tube and differential-pressure gauge. When velocities are very low (less than 3 m/s [10 ft/s]) and when great accuracy is not required, an anemometer may be used. For gases moving in small pipes at relatively high velocities or pressures, orifice-disk meters or venturi meters may be used. These are valuable as continuous or permanent measuring devices. 

When the veloeity pressure is more than 5% of the pressure rise, it should be determined by a pitot-tube traverse of two stations. For each station, the traverse consists of 10 readings at positions representing equal areas of the pipe cross section, as shown in Figure 20-2. The average velocity pressure Py is given by... 

Figure 20-2. Traverse points in pipe. (Power Test Code 10, Compressors and Exhausters, American Society of Mechanicai Engineers, 1965.)...

Velocity traverse techniques must be used when, due to the configuration in piping, nozzles, or orifice plates, etc., cannot be used. 

LOCA, is presented in Table 3.4.5-1. In preparing the event tree, reference to the reactor s design determines the effect of the failure of the various systems. Following the pipe break, the system should scram (Figure 3.4.5-2, node 1). If scram is successful, the line following the node goes up. Successful initial steam condensation (node 2 up) protects the containment from initial overpressure. Continuing success in these events traverses the upper line of the event tree to state 1 core cooled. Any failures cause a traversal of other paths in the evL-nl tree. 

The concrete block walls of the cell housing the generator tube and associated components are 1.7 meters thick. The facility also includes a Kaman Nuclear dual-axis rotator assembly for simultaneous transfer and irradiation of reference and unknown sample, and a dual Na iodide (Nal) scintillation detector system designed for simultaneous counting of activated samples. Automatic transfer of samples between load station to the rotator assembly in front of the target, and back to the count station, is accomplished pneumatically by means of two 1.2cm (i.d.) polyethylene tubes which loop down at both ends of the system and pass underneath the concrete shielding thru a pipe duct. Total one-way traverse distance for the samples is approx 9 meters. In performing quantitative analysis for a particular element by neutron activation, the usual approach is to compare the count rates of an unknown sample with that of a reference standard of known compn irradiated under identical conditions... 

Soil samples were collected along a traverse over the Honerat kimberlite and extended off the kimberlite approximately 75 m SE and 225 m NW from the pipe s centre (Fig. 1). Although it is common practice to collect samples from upper B-horizon soil (Levinson 1980 Bajc 1998 Mann et al. 2005) our samples were collected from C-horizon soil because GAGI samplers were placed at a depth of 60 cm (well below the B horizon). Within 8 hours of sampling, a portion of each soil sample was mixed with Milli-Q water (1 1) to create a slurry. The values of pH and oxidation-reduction potential (ORP) were determined in each slurry. Ammonia acetate leach of the soil samples were performed at Acme Analytical Laboratories, Vancouver, where 20 ml of ammonium acetate was mixed with 1 g soil sample and elements were determined by inductively coupled plasma-mass spectrometry. The GAGI samplers installed at Unknown were placed in piezometers and submerged in water at a depth of approximately 1 m below ground surface. 

The water which thus traverses the scrubber, and becomes partly saturated with tar, ammoniacsl matter, and naphtha, flows off from the base by a pipe into a tank, net exhibited in tha drawing, but which may be designated by z, Fig. 40. After passing through the first scrubbers,... 

Solution. The transverse diffusion rate is controlled by the relatively slow crystal diffusion rate because the diffusing atoms must traverse the patches of perfect crystal between the dislocation pipes. Therefore, when the dislocations are discretely spaced, a good approximation is the simple result... 

To liquefy air, it is compressed by a pump to a pressure of 150 atmospheres 5 it then traverses a coil of copper pipe,... 

Henri de Pitot invented the Pitot tube in 1732. It is a small, open-ended tube that is inserted into the process pipe with its open end facing into the flow. The differential between the total pressure on this open impact port and the static pipeline pressure is measured as an indication of the flow. The Pitot tubes provide a low-cost measurement with negligible pressure loss and can also be inserted into the process pipes while the system is under pressure (wet- or hot-tapping). They are also used for temporary measurements and for the determination of velocity profiles by traversing pipes and ducts. 

Transit-time flowmeters measure the time taken for an ultrasonic energy pulse to traverse a pipe section both with and against the flow of the liquid within the pipe (Figure 3.97). The flow rate is the difference in transit times. Transit-time flowmeters are widely used in water treatment and chemical plant applications. This type of ultrasonic meter is considerably more expensive than the Doppler version, but it offers better accuracy. Unlike the Doppler meter, it is usable only on relatively clean fluid applications. Its advantages... 

The manufacturer shall perform all fabrication and welding in accordance with an established written procedure. The first production pipe shall be sectioned and tested. Included in the testing shall be the normal physical property and nondestructive testing as well as a microhardness traverse across the weld and heat-affected zone (HAZ). The hardness shall not exceed 280 HV1Q at any location. Test results from previous production runs of these grades may be considered to fulfill this requirement if the chemical composition and wetding procedure used are substantially the same as proposed for this order. 

The major part of the gas enters the vessel at the top and flows down as shell cooling gas. It then passes through the feed-effluent heat exchanger and flows upwards through a central pipe to the first catalyst bed, which is traversed from the inside to the outside. After the effluent from the first bed has been quenched with cooler recycle gas, it enters the second bed and passes through it in the inward direction. The cold gas enters through the bottom of the vessel and is mixed with the inlet gas to the first bed for temperature control. 

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